A Study of the Effect ofLead Oxide on Structural and Elastic Properties of Recycled Silica Gel Glassby Ultrasonic and FTIR Technique
The purpose of this work is to study structural and elastic properties of recycledsilica gel glass (RSG) by ultrasonic and FTIR techniques. The 10CaO – xPbO – (90–x) RSG glass systems (where x = 20, 25, 30, 35, 40 and 45 mol%) were prepared by using melt-quenching method. Densities of the glass samples were measured using Archimedes’ principle with n-hexane as the immersion liquid. The longitudinal and shear ultrasonic velocities in the samples were measured at room temperature and at 4 MHz frequency using a pulse echo technique. The obtain results showed that changes in elastic properties of the glass samples depended on the concentration of PbO. Therefore the presence of PbO resuled in the destruction of the glass network and subsequent formation of non-briding oxygen (NBO). Moreover, these results can also be supported by FTIR technique.
Elastic Properties of Recycled Soda-lime Glasses Doped with Copper(I)oxide(Cu2O) Studied by Ultrasonic Technique and Fourier Transform Infrared Spectroscopy
The purpose of this work was to study the elastic moduli and structural properties of recycledwindow glass using ultrasonic technique andFourier transform infrared spectroscopy. The glass systemof 90Recycled window glass – 10Na2O – xCu2O (where x is0.001, 0.01, 0.1 and 1.0 mol%) were prepared by melt quenching technique at the melting temperature of 1250°C for 4 h and annealing temperature of 500°C for 2 h. Then, densities of glass sample with varying the Cu2O dopant were measured. The longitudinal and shear velocities were measured by using ultrasonictechnique at 4 MHz frequency at room temperature. Next thevalue ofdensities and the ultrasonic velocities data of glasssampleswere used tocalculate the elastic properties such as longitudinal modulus, shear modulus, bulk modulus, Young’s modulus, Poisson's ratio and micro-hardness as well as physical properties such as acoustic impedance, softening temperature and Debye temperature. Finally, Fourier transform infrared spectroscopy was measured in wave number range 400 - 2000 cm-1 to study structure of the glass samples. The results indicated that the ultrasonic velocity, elastic moduli, Poisson’s ratio, micro-hardness, acoustic impedance, softening temperature and Debye temperature depended on the concentration of Cu2O dopant and could be confirmed by Fourier transform infrared spectroscopy results.
Study and Development of Electromagnetic Induction Laboratory
The study and development of electromagnetic induction laboratory have three main parts; induction voltage measurement, magnetic field measurement and the speed controls of the coils loop. The measurement and controller were performed with Raspberry Pi board. The result showed the induction wire loops speed controls was 0.002-0.007 meters per second by controlling a DC motor. The magnetic field measurement can be measured in the range of 0-170 mT. The average of magnetic field of the apparatus which has 2, 3 and 4 pairs of the cylinder magnets were 13.0±0.9, 18.7±1.2 and 25.8±1.0 mT respectively. The average of induction voltage of the coils loop width of 2, 2.8 and 4 centimeter with maximum magnetic field and maximum moving speed were 39.33±0.35, 55.44±0.51 and 77.37±0.97 µV respectively.
After Eric Mazur has proposed interactive teaching method in large class university environment namely peer instruction, ithas become favored in general because the instruction helped students got more understanding in physics. The basis of peer instruction is the classroom respond system (CRS) by using a set of multiple choice questions relates to concepts which is called ConcepTest®. Initial students used flash cards which have got the letters A, B, C and D. However, the problem for using lettered sheets is that a lecturer has to spend 2 – 3 minutes on each quiz for counting a number of students’ answers. For each counting,a lecturer gets only the holistic view of a poll on students’ answers which clarifies the result – how many students choose on A, B, C and D before and after peer discussions. By using it, class time is limited, and it has been used for counting a number of students’ answers. It means peer instruction can use about 10 – 15 percentage of classroom time for this purpose. Later, the CRS called Clicker has been developed to be able to record and display the answers immediately. The clickers cost about THB 28,748 (For 32 pieces). If the class has 50 – 60 students, it will cost about THB 57,496. At present, there is a free application which is called Plickers developed by Nolan Amy. The Plickers can be used as Clickers, but it doesn’t require devices except smartphone. The Plickers can be used up to 63 students with working with sheets of QR-code paper and only one smartphone with internet signal. Therefore, the Plickers can be widespread to any schools.
Microscopical characteristics of medicinal plants, Minusops elengi L.
and Madhuca thorelii (Dubard) H.J.Lam,
based on bark, wood and flower
Microscopical characteristic study of two medicinal plants, Minusops elengi and Madhuca thorelii based on bark, wood and flower was investigated. The objective was to provide microscopical data of the standard database specify for Thai Herbal Pharmacopoeia. The research was carried out between August 2018 and September 2019. Plant materials were surveyed and collected in Ubon Ratchathani and Srisaket provinces. Transverse section of bark, wood and all floral parts was performed and stained with 1% Safranin O in water. Anatomical features were observed by a light microscopy. The results revealed that important characteristics of both species are (1) presence of rectangular cork cells in periderm, (2) presence of laticifer in bark, (3) diffuse– porous wood, (4) presence of trichomes at sepal, (5) presence of secretory cells in petal, (6) presence of one vascular bundle in filament, (7) anthers 4-celled and (8) 3-4 colporate pollen. These characteristic evidences are useful for the standard database of Thai Herbal Pharmacopoeia.
Comparative Study of PHITS and FLUKA for Cosmic Radiation Shielding Evaluations of Low Density and Small Atomic Mass Number Materials
The two well-known Monte Carlo transport codes called FLUKA and PHITS have been used for comparing the cosmic radiation shielding properties of various low density and small mass number materials that are used for spacecraft constructing materials or components. The work is focused on the evaluation of shielding efficiency of the materials exposed to a known Solar Particle Event sources. Then we compared their effectiveness with aluminum which is the main primary metal used in spacecraft by employing FLUKA and PHITS programs. The shielding materials are liquid hydrogen, water, polyethylene and aluminum. The shielding efficiency of materials is evaluated by comparing the amount of dose absorbed by the water. The absorption doses obtaining from each material are compared with the aluminum. The efficiency comparison is made by fixing the area density of a shielding material. We found that liquid hydrogen, polyethylene and water all outperform the aluminum for Solar Particle Event Shielding. We also found that FLUKA and PHITS are alternate codes that will be produced a very similar computational results for these circumstances.
การประชุมวิชาการระดับชาติด้านวิทยาศาสตร์สุขภาพ ครั้งที่ 1 (The1st National Conference on Health Sciences Research and Innovation: Knowledge Transformation towards Thailand 4.0)
การประชุมวิชาการระดับชาติด้านวิทยาศาสตร์สุขภาพ ครั้งที่ 1 (The1st National Conference on Health Sciences Research and Innovation: Knowledge Transformation towards Thailand 4.0
The purpose of this research is designed and constructed of a small vacuum furnace. A cylindrical graphite was chosen as the material of the furnace, the cylinder aluminium and copper sheets were employed to prevent the heat radiation that transfers from the furnace to the chamber wall. A rotary pump used, the pressure of graphite furnace can be pumped up to 30 mTorr and heated up to 700 °C driving by wire and the temperature of the chamber wall is relatively remained too low. In addition, heat loss obtained from the graphite furnace by conduction, convection, and radiation were analyzed. The dominating heat loss was found to be caused by the blackbody radiation, which can thus be used to estimate the relationship between graphite furnace temperature and the drive power needed. The cylindrical graphite furnace has an inner diameter of 44 mm, the outer diameter of 60 mm and 45 mm in height, the 355.5 W of power is needed to drive the furnace to 700 °C.
The investigation of high school student's energy concept by
using analogies
Alternative energy tends to be more widespread in Thailand because the advanced technology, enhance the potential of equipment which becomes more economically rather than setting in laboratory likes in the past. For this reason students should understand profoundly about the characteristic of energy before they learned about alternative energy. To help students get more comprehension about the characteristic of energy, we need to investigate the idea about energy. There are three main reasons for the investigation (1) to know how students use analogy to describe characteristic of energy (2) to find out the most frequent characteristic that student used (3) to classify analogies for energy by using category of misconceptions which helped us to group students if there were any vague content in students’ explanation. Students were given a task to write their analogies after doing the STEM activity (Bungee Jump) in class. The answers were categorized into four terms of scientific contexts: energy can be accounted, can change forms, can be lost and can be transferred.
Developing dye sensitized solar cells with polymer electrolytes
We have fabricated dye sensitized solar cells and improved their efficiency. The working electrodes were made of Al-doped and Cu-doped TiO2 nanotubes by anodization process. We also prepared 2 polymers: the poly acrylonitrile-co-styrene and polyethylene oxide to compare efficiency of these polymer electrolytes. X-ray diffraction (XRD) was used to study the microstructure of the titania nanotubes, scanning electron microscopy (SEM) was used to study structural morphology, and UV-visible spectroscopy optical property was employed to determine the optical property. The effect of Al-doping and Cu-doping on the efficiency of the solar cells was investigated. The conversion efficiencies of poly (acrylonitrileco-styrene), Poly(ethylene oxide), Al-doped TiO2 and Cu-doped TiO2 were 0.184, 0.121, 0.008 and 0.169 respectively for irradiation of 800 W/m2 .
Developing students' learning achievement and experimental skills on buoyancy and the involvement of Newton's third law through experimental sets
The purposes of this research were: to construct packages of operations on buoyancy and the involvement of Newton’s third law, to enhance achievement score of students on buoyancy and the involvement of Newton’s third law , to enhance experimental skills on buoyancy and the involvement of Newton’s third law and to evaluate students’ attitude towards the packages of operations on buoyancy and the involvement of Newton’s third law using inquiry method. The samples were 42 grade 11 students in academic year 2016 at Hatyaiwittayalai School, Hatyai, Songkhla. The research method was one group pretestposttest design. The research tools consisted of experimental set on buoyancy and the involvement of Newton’s third law, the learning achievement test on buoyancy and the involvement of Newton’s third law and the students’ attitude questionnaires. The experimental skills of most students was in a good level . The satisfaction of most students was in a good level. The research showed the learning achievement after instruction higher than that before instruction using experimental set at the significant level of 0.05 and the class average normalized gain is in the medium gain.
Development of the Concept of Energy Conservation using Simple Experiments for Grade 10 Students
The purpose of this research was to develop students’ concept of and retention rate in relation to energy conservation. Activities included simple and easy experiments that considered energy transformation from potential to kinetic energy. The participants were 30 purposively selected grade 10 students in the second semester of the 2016 academic year. The research tools consisted of learning lesson plans and a learning achievement test. Results showed that the experiments worked well and were appropriate as learning activities. The students’ achievement scores significantly increased at the statistical level of .05, the students’ retention rates were at a high level, and learning behaviour was at a good level. These simple experiments allowed students to learn to demonstrate to their peers and encouraged them to use familiar models to explain phenomena in daily life.
Performance of ZnO-doped recycled window glass as a thermoluminescence dosimeter
Thermoluminescence properties of Thai commercial window glass provided by Guardian Industries Corporation (denoted as WG) were studied. WG was doped with varying concentrations of ZnO. The composition of glass is 90WG-10Na2O-xZnO (where x = 0.000, 0.001, 0.010, 0.100, 1.000 mol%). Glass samples were recycled by using melt quenching technique and cut into the dimensions of 6×6×1 mm3 . After irradiated glass samples with X-ray at photon energy 160 keV in absorb dose rang 0-14 mGy, the glow curve structure, TL sensitivity, linearity and minimum detectable dose were investigated.
Selected Screen for Engaging Students in Projectile Motion
Connecting physics concepts to activities that are interesting to students or what they encounter in everyday life will help students build a strong foundation. When there is an interesting activity for the student, it will result in the student responding, engaging, and enthusiasm in learning. Learning activities that are based on what students are interested in and regularly experience will enable students to understand the long and memorable experience. Both of these will enhance the student's learning experience. One of the activities that can be described in this research used the learning activity through movies, which is the application of the basic motion projectile for students to understand the characteristics of such movement. It also aims to further develop critical thinking skills of learners.
Learning Particle Physics with DIY Play Dough Model
The scientists once believed an atom was the smallest particle, nothing was smaller than this tiny particle. Later, they discovered an atom which consists of protons, neutrons and electrons, and they believed that these particles cannot be broken into the smaller particles. According to advanced technology, the scientists have discovered these particles are consisted of a smaller particles. The new particles are called quarks leptons and bosons which we called fundamental particle. Atomic structure cannot be observed directly, so it is complicated for studying these particles. To help the students get more understanding of its properties, so the researcher develops the learning pattern of fundamental particles from Play Dough Model for high school to graduate students. Four step of learning are 1) to introduces the concept of the fundamental particles discovery 2) to play the Happy Families game by using fundamental particles cards 3) to design and make their particle in a way that reflects its properties 4) to represents their particles from Play Dough Model. After doing activities, the students had more conceptual understanding and better memorability on fundamental particles. In addition, the students gained collaborative working experience among their friends also.
Atomistic tight-binding calculations of near infrared emitting CdxHg1-xTe nanocrystals
I present the structural and optical calculations for CdxHg1xTe zinc-blende nanocrystals with the experimentally synthesized Cd compositions (x) in the framework of atomistic tight-binding model (TB) and configuration interaction description (CI). This atomistic tight-binding model incorporates the sp3 s ⁄ orbital and the first neighbouring interaction, in addition to the non-linear dependence of compositions on the band gaps the bowing factor is involved into this model through the extended virtual crystal approximation (VCA). The information of DOS highlights that the contribution of the conduction and valence bands is subjected by cation and anion atoms, respectively. The improvement of the optical band gaps in CdxHg1xTe nanocrystals is presented with the increasing Cd compositions. The optical band gaps can be used to tune their optical properties across a technologically useful range from 688 nm to 2755 nm which can be implemented for the near infrared emitting devices. In addition, the enhancement of the optical property is reported with the increasing Cd contents. With the increasing Cd compositions, the atomistic electron-hole Coulomb interaction is mainly increased, whereas the atomistic electron-hole exchange interaction is reduced. The Stokes shift and fine structure splitting are progressively reduced with the increasing compositions and diameters. The application of fine structure splitting is utilized to implement as a source of entangled photon pairs in the quantum information. Finally, the comprehensive computations of alloy CdxHg1xTe nanocrystals effectively determine the composition- and sizedependent structural and optical properties which render these nanocrystals promising candidates as the near infrared emitting devices and optical amplifiers
Influence of ionic radius modifying oxides on the elastic properties of glasses using ultrasonic techniques and FTIR spectroscopy
We prepared a new series of glasses by melting a mixture of recycled window glass and different metal oxides. We investigated the effects of the modifying ionic radius on elastic moduli, Poisson's ratio and fractal bond connectivity. The Debye temperature, softening temperature and latent heat of melting were measured. The bond compression model was compared with the experimental values. The structural properties were determined using FTIR spectroscopy. The results show that ionic radius has significant effects on the structural properties. The results of Poisson's ratio and fractal bond connectivity reveal that the ionic radius of modifiers could be used for the prediction of the structural properties of glass samples.
เชิดศักดิ์ บุตรจอมชัย
Q3
นานาชาติ
วันที่ตีพิมพ์
2017-10-01
ชื่อวารสาร
Physics and Chemistry of Glasses - European Journal of Glass Science and Technology Part B
r-GO/MWCNTs Nanocomposite Film as Electrode Material for Supercapacitor
We synthesized a reduced graphene oxide (r-GO) multi-walled carbon nanotube (MWCNTs) nanocomposite film via layer by layer (LBL) assembly. This structure was prepared by vacuum filtration and heat-treated at a low temperature of 500°C. The morphology of the sample was determined by field emission electron spectroscopy (FE-SEM). The structural detail and the chemical analysis were characterized by using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The cyclic voltammetry (CV) curve of r-GO/MWCNTs nanocomposite appeared nearly rectangular in shape. The current density (A/g) was gradually increased by increasing the scan rate of the voltage, as high as a scan rate of 500 mVs-1 . At a current density of 10 mAg-1 , the specific capacitance of the nanocomposite, estimated by galvanostatic (GA) charge/discharge measurement, is 150 Fg-1 . These nanocomposites can be developed for supercapacitor electrodes.
Theoretical simulation of exciton and biexciton of ZnTe/ZnS type-I and ZnTe/ZnSe type-II core/shell nanocrystals
In the present study the atomistic tight-binding theory and configuration interaction description are used to simulate the exciton and biexciton of ZnTe/ZnS type-I and ZnTe/ZnSe type-II core/shell nanocrystals. The control and tunability of the exciton and biexciton are properly engineered by the type of the band profiles and thickness of the growth shell. In particular, the exciton energies, biexciton energies, interacted coulomb integrals, exciton binding energies, biexciton binding energies, negative exciton binding energies and positive exciton binding energies are entirely sensitive to the type and dimension of the coated shells. The energies of the exciton and biexciton are reduced with the increasing growth shell thickness. In addition, the exciton and biexciton energies of ZnTe/ZnS type-I core/shell nanocrystals are greater than those of ZnTe/ZnSe type-II core/shell nanocrystals. This insight is important for a theoretical understanding and practical control by band alignments and sizes in the growth shells in order to assess the potential of particular core/shell nanocrystal structures for single exciton lasing application.
วรศักดิ์ สุขบท
Q3
นานาชาติ
วันที่ตีพิมพ์
2017-08-01
ชื่อวารสาร
MAEJO INTERNATIONAL JOURNAL OF SCIENCE AND TECHNOLOGY
Atomistic tight-binding theory in 2D colloidal CdSe zinc-blende
nanoplatelets
Using atomistic tight-binding theory in conjunction with the configuration interaction description, I investigate the structural and optical properties of colloidal CdSe zinc-blende nanoplatelets. I highlight that the new class of CdSe zinc-blende nanoplatelets has strong thickness and lateral size dependence on the natural properties. In an effort to theoretically demonstrate the dependent atomistic behaviors, the single-particle spectra, orbital occupation, optical band gaps, electron–hole wave function overlaps, oscillation strengths, ground-state Coulomb energies and Stokes shift are realized under different lateral (lx ) and vertical (lz) sizes. The electronic structures and optical properties of CdSe zinc-blende nanoplatelets are monotonically dependent on the lateral sizes, while those of CdSe zinc-blende nanoplatelets are nonmonotonically sensitive to the vertical sizes. This atomistic prediction will contribute to the understanding of physical behaviors in colloidal CdSe zinc-blende nanoplatelets and will deliver some significant data for experimental study which can be produced by inexpensive means.
Optical transitions of native defects in single-walled carbon nanotubes: Time-dependent density functional theory study
Optical transitions of a pristine (8,0) single-walled carbon nanotube (SWCNT) and the (8,0) SWCNT containing three types of defects were calculated based on electronic structures obtained using the density functional theory (DFT) corrected by the van der Waals (vdW) interactions. The photon absorption energies (PAE) of the pristine (8,0) SWCNT and defected (8,0) SWCNTs were calculated using time-dependent density functional theory (TDDFT). We found that all three defects studied, namely, single vacancy, diatom vacancy, and Stone-Wales, have characteristic PAEs lower than the PAE of the pristine SWCNT. The calculated PAE could be used to identify native defects in semiconducting (8,0) SWCNT.
Theoretical study of ethanol interaction with pristine and P-doped single-walled carbon nanotubes
Feasible interactions between metallic single-walled carbon nanotubes (CNT) and ethanol gases were carried out using theory of first principles based on DFT. Also, the vdW correction and spin polarized were included in this account. The equilibrium position, adsorption energy, charge transfer and electronic band structure of ethanol rearranged inside and outside pristine also with P-doped nanotubes were calculated to estimate the responses of P-CNT. It was found that the ethanol preferred to absorb inside than outside the tube and revealed that ethanol fit suitably inside CNT at diameter of 8.19 Å. Conversely, larger size of nanotubes diameter than 13.63 Å, the ethanol equivalently forms both inside and outside carbon nanotubes. The investigations on electronic properties have been shown that ethanol performed as electron-withdrawing group because of hydroxyl group attached with ethyl group. Then, the electron in CNT moves toward the adsorbate thereby enhancing its conductivity. Furthermore, doping an impurity, Phosphorus, on the surface improved the absorption and the characteristic of all intermolecular interactions.
Play dough circuits: A tangible and friendly medium for understanding physics
Students consider that physics is difficult because of its abstract nature and the involvement of mathematics. One of the most difficult topics is a simple direct current circuit. Physics education research shows that students learn better when they construct their own understanding of scientific ideas within the framework of their existing knowledge. To accomplish this process, students must be motivated to engage with the content actively and be able to learn from that engagement. The purpose of this research was to compare the grade 6 students' understanding of the scientific concept of simple direct circuits before and after participating in a STEM activity that involved the building of circuits from play dough. Twenty questions from the Interpreting Resistive Electric Circuit Concepts Test were selected to evaluate students' reasoning regarding direct current resistive electric circuits. Findings revealed that the students' scores working with the different conditions after learning were significantly higher than they were before learning. However, analysis on learning progress showed that the group that had to create more works had higher normalized gain than the group that created less works. When the work was analysed with rubric criteria, it illustrated that more conditions caused more complexity and diversity to the work. In short, the condition or situation set to students affected work creation.
DIY small scale resonance tube for measuring the speed of sound in air
This research invented a small scale with no cost experimental set to determine the speed of sound in the air by resonance method. Equipment consisted of a bubble tea straw with label measuring scale, a full plastic water bottle and the n-Track Tuner (iOS) or Guitar Tuner (Android) application for generating sound waves. Sound waves were sent down a bubble tea straw filled with an air. The waves reflected back up the straw from a water surface and interfered with the waves traveling downward. By properly adjusting the water level, a resonance condition could be established. By knowing the frequency of the sound wave and the position of the water level for two different resonant lengths, the speed at which sound waves travel through the air was found. In this experiment, the frequency was specified 1, 500 Hz at 24.00 °C, 26.00 °C and 30.00 °C respectively. The sound speed which was calculated was 345.0, 347.0 and 349.0 m/s respectively. The standard value of sound speed at the same temperature was 345.4, 346.6 and 349.0 m/s respectively. The percent error value of the sound speed was calculated to compare with the standard value of sound speeds was 0.1%, 0.1% and 0.0% respectively. This an experiment was effective and could be efficiently used in educational physics. Moreover, it is easy to use, low cost, and portable. Students can also prepare the equipments themselves.
Motion Blitz: A new card game for assessing students' thinking level about physics
Critical thinking and problem-solving skills are crucial for the 21st century. Game-based learning (GBL) is a powerful teaching strategy for fostering these skills amongst students. GBL can reinforce knowledge and bridge the gap between what is learned by creating dynamic, fun, and exciting learning environments. This research developed a card game called "Motion Blitz" for teaching the physics concept of motion in one and two dimensions. Motion Blitz is a quick matching card game that consists of a deck of "Motion Cards" which picture motions in daily life and a selection of "Motion Symbols" displaying a path of motions: linear, projectile, circular, rotational, rolling, and simple harmonic motions. To play the game, one player starts by flipping over one of the "Motion Cards", then simultaneously everyone tries to figure out the proper "Motion Symbol" to grab. Figure it out and grab the right one to get the card/point. After playing, the teacher uses questions to stimulate student thinking and help students construct scientific knowledge. Finally, 12 questions according to Bloom's taxonomy are administrated to students. These questions are classified according to different cognitive levels ranging from low-level thinking (knowledge, comprehension) to high-level thinking (application, analysis, synthesis, and evaluation). Data analyses showed Motion Blitz's ability to elevate students' thinking level, over 90% of students scored well at a low level and 59% at a high level approximately. In addition, data indicated that students' thinking scores became lower at a higher level of thinking.
The projectile tube experiment for improving high-school physics conceptual understanding
This research aimed to design the simple apparatus to improve students' conceptual understanding in projectile motion. The projectile tube experiment was a simple apparatus that consisted of a one-meter PVC tube, a 1200-watt hair dryer, a hard sheet of paper, and a ping pong ball. The participants were 30 grade 10 students who were selected by non-random sampling in the second semester of the academic year 2018. The research tools consisted of learning lesson plans and a multiple-choice learning achievement test. The class activity was conducted by using the Interactive Lecture Demonstrations (ILDs) method with Tracker Video Analysis. The results showed that the experiment set worked perfectly and could be used for learning the projectile concept. The students' achievement score was significantly increased at a statistical level of .05 and the average of students' normalized gain was in a medium gain regime.
An Arduino board with ultrasonic sensor investigation of simple harmonic motion
An Arduino, one of the most popular microcontroller platforms, is widely used in teaching and learning STEM. It is really open source software and hardware, huge community, low cost boards and peripherals, and simple programming language. This research aims to develop an Arduino-based physics investigation of the simple harmonic motion (SHM) of mass on a spring. This rich cross curricular STEM activity integrates electronics, computer programming, physics, and mathematics in a way that is both experimentally exciting and intellectually rewarding. The experimental data are collected with the help of an HC-SR04 ultrasonic distance sensor and an Arduino Uno board. The data are then graphed and analysed using Microsoft Excel in real-time. The experiment data can be used to investigate Hooke's law. The elastic constant of the spring, k = 16.54 N/m, is very close to the value determined from the period of the SHM. This Arduino-based investigation of SHM can be helped the students to improve both their experimental and theoretical skills.
Study on electron and hole states in tilted quantum well structures
In this study, the energy states of electron and hole in GaxIn1-xNyAs1-y/GaAs tilted quantum well structure have been theoretically investigated. The content of x and y are 0.65 and 0.005 respectively. The energy states and wave functions have been calculated by solving the Schrödinger equation in real space. The well width of 2-10 nm, barrier width of 2-10 nm and tilted layer width of 1-3 nm are considered in this work. The results show that the electron and hole energies decrease with increasing the well width and tilted layer width. The wave functions are both symmetric (ground state) and anti-symmetric (the first excited state), and spread out as the well width increases. In addition, the barrier width of couple tilted quantum well structure has also been studied. It is found that the probability of finding electron and hole are equal in both wells and the wave function within barrier layer decreases with increasing the barrier width as well. The ground state energy increases and the first excited state energy decreases as the barrier increases. As a result, the two states tend to the same level when the barrier is more than 8 nm. This is because the wide barrier can decrease the interaction between two quantum wells and makes each quantum well acts as an isolated quantum well with no interaction between them.
Luminescent properties of calcium-alumino-silicate glasses (CaAlSi) doped with Sm2O3 and co-doped with Sm2O3 + Eu2O3 for LED glass applications
A new glass system of calcium-alumino-silicate doped with Sm2O3 and co-doped with Sm2O3 ± Eu2O3 was fabricated in order to improve the efficiency of the red emission for phosphor glass materials. The optical properties of the glass samples were studied by measurements using UV–vis absorption spectra and excitation energy. The results showed that 403 nm of photon energy is effective to elevate the electron in a ground state to an excited state. This photon energy was used to study the emission spectra and energy transfer. The luminescence intensity O/R ratio of the glass samples showed a stronger red shift colour with an increase in the dopants. Moreover, the quantum yield (QY) of the glass samples was measured, and the results showed that Eu2O3 can increase the QY by acting as activator. These results indicate that the glass samples are a good potential candidate for LED applications.
Effect of quantum well width on the electron and hole states in different single quantum well structures
In this study the electron and hole states in Al0.33Ga0.67As/GaAs single quantum well structures including squared QW, step QW and tilted QW, have been theoretically studied by solving the Schrodinger equation in real space. The energies and wave functions of electron and hole are calculated for different well widths. It is found that energy level of electron and hole decreases with increasing the well width. Adding step or tilted layers gives rise to the decrease of electron and hole energy levels. The ground state energy level in a tilted single quantum well structure is lower than that in a step single quantum well structure. It is also found that the energy of electron and hole ground states do not change as the width of step layer increase. This is because the ground state occupies in a lower well only. The wave functions are symmetric (ground state) and antisymmetric (the first excited state). The maximum of ground state wave function is at the central of the well and the probability of finding electron and hole in excited states are different in each region. The hole levels are lower than the electron levels due to the lower well depth and higher mass of hole compared to electron.
Electrical and sensitivity properties of ZnO/TiO2
heterojunction nanocomposites for ammonia gas sensor
The ZnO/TiO2 heterojunction nanocomposites were synthesized via a thermal process. The morphology of the samples showed TiO2 nanoparticles with rang of 50 – 100 nm in diameter and ZnO nanoparticles with size of upper than 100 nm. The XRD patterns of ZnO/TiO2 nanocomposites indicate ZnO, anatase, and rutile phases. The current - voltage characteristics of ZnO and TiO2 nanoparticles, and ZnO/TiO2 heterojunction nanocomposites show behaviour of ohmic contact materials. The material sensitivity was measured under an ammonia atmosphere for 200 seconds at room temperature. The results showed maximum response of ZnO/TiO2 nanoparticles with 27.30 for 200 seconds.
value='Synthesis of 6Chloro-7-arylaminoisoquinoline-5,8-dione and Its Derivatives as Cytostatic Compounds'
Our group has previously reported the synthesis of azanaphthoquinone annelated pyrrole derivatives which showed good inhibition on cervical carcinoma (HeLa Cell). In this work, we were interested on introducing sulfur atom into the core structure by condensation with thiosemicarbazide and thiourea to obtain the potential anticancer compounds. The synthetic pathway started from oxidation reaction of 5-hydroxyisoquinoline (5) to give 6,7- dichloro-isoquinoline-5,8-dione (6). The substitution of 6,7-dichloroisoquinoline-5,8-dione (6) with aniline and 1,4-phenylenediamine furnished the corresponding products 2a and 2b, respectively, in good yields. Condensation of thiourea and thiosemicarbazide into 2a and 2b yielded the corresponding 3a-b and 4a-b in good yields. The evaluation of cytotoxicity on human colon adenocarcinoma cells (HT-29 cells) and human heptatoadenocacinoma cells (HepG2 cells) showed that all synthesized compounds 2-4 exhibited good cytotoxicity. Introduction of sulfur atom into the core structure was found to enhance the cytotoxicity of the compounds. Compounds 2b, 3b and 4b bearing an amino (-NH2) group on the aromatic ring exhibited higher cytotoxicity in comparison to those with a hydrogen atom (compounds 2a, 3a and 4a). '
นิภาวรรณ พองพรหม
ยังไม่มีระดับ Quartile Scor
นานาชาติ
วันที่ตีพิมพ์
2019-02-07
ชื่อวารสาร
Proceedings of Pure and Applied Chemistry International Conference 2019 (PACCON 2019)
Study on gamma-ray shielding properties of lead tellurite glass systems using PHITS
The gamma-ray shielding properties, mass attenuation coefficient, mean free path and half value layer of lead tellurite glass systems were investigated in the photon energy range of 0.015–15 MeV using particle and heavy ion transport code system (PHITS) with the use of narrow beam transmission technique. The gamma shielding efficiency of studied glass systems was compared to that of standard concretes in terms of mean free path and half value layer. The obtained results show that PHITS is very capable for investigation of radiation shielding properties to good accuracy with maximum percentage differences of less than 2% comparing to the results by XCOM database. This will make a useful alternative technique for studying radiation parameters of other glasses, for which no experimental results are available.
Investigation of the radiation shielding capability of xPbO-(50-x)BaO-50B2O3 glass system using Geant4, Fluka, WinXCOM and comparison to the experiment data
In this study, mass attenuation coefficient (\(\mu _{\mathrm {m}}\)), transmission fractions (T), effective atomic numbers (\({\hbox {Z}}_{\mathrm {eff}}\)) and half-value layer (HVL) of the \({x}\hbox {PbO}\)–\((50-x)\hbox {BaO}\)–\(50 {\hbox {B}}_2 {\hbox {O}}_3\) (where \(x = 10, 20, 30, 40 \, \hbox {mol}\%\)) glass system have been determined from the Monte Carlo simulations carried out with Geant4 and Fluka simulation toolkits and WinXCOM database software. The calculated results were compared with the experimentally obtained \(\mu _{\mathrm {m}}\) values of the selected glass in order to validate the Geant4 model of HPGe detector and Fluka model of NaI(Tl) detectors. T, \({\hbox {Z}}_{\mathrm {eff}}\) and HVL shielding parameters of the studied glass system indicate that increase of PbO content from 10 to 40% results in a better shielding behaviour thanks to the high atomic number of lead.
Density-functional study of hydrazine doped single-walled carbon nanotubes as an n-type semiconductor
The theoretical study of hydrazine in the presence of moisture doped single-walled carbon nanotube (SWCNT) where the donor state (DS) occurred in the electronic band structure, which has previously been reported. Herein, We reveal that the density functional theory (DFT) studies of pure hydrazine formed the hydrogen bond network (HBN) on SWCNT, leading to the n-type behavior. DFT approaches including van der Waals corrections were carried out to understand the specific configuration of hydrazine, which causes the occurrence of the DS. The electronic band structures are classified according to three groups. First, is the impurity state below the maximum valence state (ISBMVS). Second, is the impurity state close to (below) the maximum valence state (ISCMVS), and third, is the DS. The reduced density gradient (RDG) approach and the Bader charge analysis were used to address a specific hydrazine molecule, which caused the DS to occur. The NMR chemical shifts and UV–Vis spectroscopic parameters can be used for comparison with experiments to confirm the theoretical models.
สิทธิพงษ์ โกมิล
Q2
นานาชาติ
วันที่ตีพิมพ์
2020-10-20
ชื่อวารสาร
Physica E: Low-dimensional Systems and Nanostructures
Theoretical Investigation of Electronic and Magnetic Optical Properties of CdS Doped and Co Doped with Transition Metals (Mn, Fe, and Cu): Spin Density Functional Theory
On the basis of spin density functional theory (DFT), the structural, electronic, and magnetic properties of cadmium sulfide (CdS) doped and co-doped with transition metals (TMs) is scrutinized. The TM doped and co-doped systems convince the structural, electronic, and magnetic alterations of CdS semiconductor. The total magnetization of the studied systems is mostly contributed by transition atoms and slightly by S atoms. For mono-doped CdS, the hybridization between the localized d orbitals of TM and the p orbitals of S produces the magnetism. For co-doped CdS, the magnetism is generated from the double-exchange mechanism, the p-d and d-d hybridizations. The p-d hybridization is more prominent than the d-d hybridization. (Cd, Cu)S, (Cd, Cu, Mn)S, and (Cd, Cu, Fe)S exhibit the half-metallic character worthwhile for the spintronic applications. Finally, CdS doped with suitable impurities is an interesting dilute magnetic semiconductor and can be a potential contender for spintronic applications.
Atomistic tight-binding theory of structural and optical properties in PbX (X 5 S, Se, and Te) nanocrystals
The computational tool integrating empirical tight binding and full configuration interaction method is utilized to study the structural and optical properties of spherical PbX (X 5 S, Se, and Te) nanocrystals under various diameters. The nanocrystal architecture plays an essential role in the control of the structural and optical properties. The appearance of the quantum confinement is caused by the reduction of the optical band gaps with the increasing diameters. By changing the chalcogenide types and diameters, the band gaps are modified, with their wavelengths from 380 to 2500 nm, technologically applying for the visible and near-infrared optical devices. The tight-binding band gaps agree well with previously published theoretical and experimental values. The atomistic electron–hole interactions are mainly influenced by the diameters and chalcogenide types. Using the Stokes shift and fine structure splitting, PbS nanocrystal with the immense size may be implemented as a source of entangled photon pairs and optical filter. Finally, the theoretical study reveals the distinctive properties of PbX (X 5 S, Se, and Te) nanocrystals by changing their architecture for applications in optoelectronic devices and microscopy.
Emergence of the half-metallic performance in transition-metal doped BAs semiconductor: a first-principles study
A spin density functional study of structural, electronic and magnetic properties of BAs semiconductor doped with different transition metals is reported. Cr is favourable to dope in BAs semiconductor. Transition metal dopants increase the lattice parameters and their volumes. The net magnetisation is mainly donated from transition metal, As and B, respectively. The computations remark that the transition metals introduce the d orbitals inside host band gap. The magnetism is formed by the hybridisation between d orbitals of transition metal and p orbitals of As, called p-d hybridisation. Fe and Cu doping in BAs semiconductor become metallic. The semiconductor to dilute magnetic semiconductor transformation by doping with Cr, Mn and Co is important for exploring the possibilities of the spintronic applications. Finally, this research offers the innovative perception into the nature of transition metals doping in BAs semiconductor at a quantitative level and envisages a new spintronic materials.
Tailoring doping effect in olivine-type NaMnPO4
: insights from density functional theory
On the basis of spin density functional theory, this paper comparatively investigates the electronic properties of NaMnPO4 doped with As, N and Sb using the generalized gradient approximation (GGA) with the functional parameterized by Perdew–Burke–Ernzerhof correction (PBE). Such doped ions significantly alter the lattice parameters and cell volumes. Density of states (DOS) demonstrates that the dopants introduce impurity states near the edge of the conduction bands. The band gaps are obviously reduced in the presence of the dopants, indicating the better electronic conductivity. According to Mulliken Population Analysis, the ionic character of Na-O bond is reduced by the dopants, leading to the flexible sodium diffusivity. Due to the calculations, Sb ion enhances more electronic conductivity and diffusion of NaMnPO4 in comparison with As and N atom. Finally, we expect that this work will be supportive to design these materials for rechargeable batteries based on sodium ion.
Tracking Cosmic-Ray Spectral Variation during 2007-2018 Using Neutron Monitor Time-Delay Measurements
The energy spectrum of Galactic cosmic-ray (GCR) ions at Earth varies with solar activity as these ions cross the heliosphere. Thus, this "solar modulation" of GCRs provides remote sensing of heliospheric conditions throughout the ~11 yr sunspot cycle and ~22 yr solar magnetic cycle. A neutron monitor (NM) is a stable ground-based detector that measures cosmic-ray rate variations above a geomagnetic or atmospheric cutoff rigidity with high precision (~0.1%) over such timescales. Furthermore, we developed electronics and analysis techniques to indicate variations in the cosmic-ray spectral index using neutron time-delay data from a single station. Here we study solar modulation using neutron time-delay histograms from two high-altitude NM stations: (1) the Princess Sirindhorn Neutron Monitor at Doi Inthanon, Thailand, with the world's highest vertical geomagnetic cutoff rigidity, 16.7 GV, from 2007 December to 2018 April; and (2) the South Pole NM, with an atmosphere-limited cutoff of ~1 GV, from 2013 December to 2018 April. From these histograms, we extract the leader fraction L, i.e., inverse neutron multiplicity, as a proxy of a GCR spectral index above the cutoff. After correction for pressure and precipitable water vapor variations, we find that L roughly correlates with the count rate but also exhibits hysteresis, implying a change in spectral shape after a solar magnetic polarity reversal. Spectral variations due to Forbush decreases, 27 day variations, and a ground-level enhancement are also indicated. These methods enhance the high-precision GCR spectral information from the worldwide NM network and extend it to higher rigidity.
In this study, six newly developed glass systems with nominal composition of 50B2O3 − 20BaCO3 – 30Li2O3 – xNiO where (x = 0, 0.01, 0.025, 0.05, 0.1 and 0.15 wt%) have been prepared by conventional melting method. Structure, physical, optical, gamma-ray and neutron shielding features for the prepared samples were investigated. The amorphous nature was tested by using X-ray diffraction measurements for each glass sample. Density and molar volume were calculated. UV–Vis spectra of the prepared samples were observed in the range of 190–1100 nm. Band gaps for indirect transition (EOpticalIndirect) and for direct transition (EOpticalDirect) decreased from 3.02 eV to 1.89 eV and from 3.27 to 2.91, respectively. Index of refraction (n) takes values between 2.38 and 2.74. The static dielectric constant () varies from 5.70 to 7.53, while the optical dielectric constant () varies from 4.70 to 6.53 for the proposed glasses. Mass attenuation coefficients () were generated by using PHITS code and WinXCOM program in the photon energy range of 0.015–15 MeV for all prepared samples. The results of PHITS code and WinXCOM program were observed in good agreement. The values were then used to compute the gamma shielding parameters like the effective atomic number (Zeff), mean free path (MFP), electron density (Neff), and half value layer (HVL) for the glasses involved. Additionally, neutron shielding capacity of these glasses was estimated by determining removal cross sections for the fast neutrons. It was found that radiation shielding features were evolved by adding NiO content in the present glasses. It can be concluded that our prepared glasses are superior shields and can be used in radiation shielding applications as compared with different international shielding materials.
Effect of heat treatment temperature on microstructure and luminescence properties of alkaline earth aluminosilicate glass-ceamics doped with Eu3+
Alkaline earth aluminosilicate single phase glass ceramics doped with rare earth (Eu3+) were successfully prepared, from the BaO-MgO-Al2O3-SiO3 glass system, by high temperature melt-quenching following by a heat treatment process to explore red phosphor materials for potential application in solid state lighting devices. It is experimentally verified that the BaAl2Si2O8 crystallites formed as a single crystalline phase after glass crystallization at temperature exceed 950o C. Participation of Eu3+ suppressed nucleation and growth rate of the BaAl2Si2O8 crystallites. Random distributions of approximately spherical shape crystallites are clearly seen in both glass ceramics with and without Eu3+ addition. PL spectra obtained from the glass ceramics with different treatment temperatures are not significantly different. Five distinguished emission peaks, located at 576, 589, 612, 649 and 701 nm, associating to transition emission between electronics states of the Eu3+ are identified. This provides strong red emission glass ceramic with the probable application as a red phosphor material.
Effect of substituted VIB transition metals on structural, electronic and magnetic properties of indium oxide: spin density functional calculations
The main raising propose in material science is to modify the structural, electronic, optical and magnetic properties. Here, the effect of substituted VIB transition metals in In2O3 semiconductor is analysed utilising the spin density functional theory with the generalised gradient approximation (GGA) by Perdew–Burke–Ernzerhof (PBE) formulation. W doping in In2O3 semiconductor is the most stable among all studied structures. All VIB transition metals transform semiconducting to metallic behaviour. The total magnetisations are mostly from the transition metal atom and marginally from I and O atom. The d orbitals of transition metals are predominantly dominated in the conduction bands. The VIB transition-metal dopants induce the red shift in the first peaks of the absorption spectra. The absorption coefficients are reduced when doping. Finally, the first quantitative theoretical prediction of In2O3 semiconductor doped with VIB transition metals is expected to a suitable contender for the new applications and still waits for the experimental authentications.
Structural and electronic properties of non-metal doping in Li2FePO4F compound: spin density functional theory
I comparatively determine the structural and electronic properties of Li2FePO4F compounds with F substituted by Cl, Br and I atom using the spin density functional theory with Perdew–Burke–Ernzerhof generalised gradient approximation (GGA + U). The lattice parameters and volumes are improved by the dopants because of the greater atomic radius in dopants. Non-metal doping in Li2FePO4F reduces the band gap. When doping, Li ion can mobile efficiently because of the reduced ionic character and increased Li-Dopant bond lengths. As the computations, Li2FePO4(F, I) material possesses the highest electronic conductivity among all compounds. Finally, this non-metal doping research provides the detailed information for understanding the enhancement mechanism and assists more broadly in the material design for the wider class of fluorophosphates cathodes in Li-ion rechargeable batteries.
Theoretical Investigation of Electronic and Magnetic Optical Properties of CdS Doped and Co Doped With Transition Metals (Mn, Fe, and Cu): Spin Density Functional Theory
On the basis of spin density functional theory (DFT), the structural, electronic, and magnetic properties of cadmium sulfide (CdS) doped and co-doped with transition metals (TMs) is scrutinized. The TM doped and co-doped systems convince the structural, electronic, and magnetic alterations of CdS semiconductor. The total magnetization of the studied systems is mostly contributed by transition atoms and slightly by S atoms. For mono-doped CdS, the hybridization between the localized d orbitals of TM and the p orbitals of S produces the magnetism. For co-doped CdS, the magnetism is generated from the double-exchange mechanism, the p-d and d-d hybridizations. The p-d hybridization is more prominent than the d-d hybridization. (Cd, Cu)S, (Cd, Cu, Mn)S, and (Cd, Cu, Fe)S exhibit the half-metallic character worthwhile for the spintronic applications. Finally, CdS doped with suitable impurities is an interesting dilute magnetic semiconductor and can be a potential contender for spintronic applications.
Investigation on elastic properties and radiation shielding of lead-recycled cathode ray tube glass system
The elastic and radiation shielding properties of lead-recycled cathode ray tube (CRT) glass were investigated in order to study the possible reduction in the use of toxic lead oxide glass by partial replacement using CRT glass waste. The elastic properties of lead-recycled glass were studied using the pulse-echo ultrasonic technique and it was found that the elastic properties varied with CRT content in the glass. This indicated the existence of some modifying cations in the CRT. The radiation shielding properties of the glass were also studied by means of the calculated mass attenuation coefficient, mean free path, and half-value layer using the WinXCom program. The addition of CRT glass was found to deteriorate the radiation shielding properties of lead glass. However, lead-recycled CRT glass still exhibited better radiation shielding properties than the conventional barite concrete. Therefore, lead-recycled CRT glass can be a potential candidate for radiation shielding applications.
Band offset determination of p-NiO/n-TiO2 heterojunctions for applications in high-performance UV photodetectors
Nickel oxide (NiO)-decorated titanium dioxide (TiO2) heterojunction photodetectors were prepared by two-step anodization. Surface scattering of NiO particles was successfully controlled by varying second-step anodizing voltage, with substantially less clustering of NiO particles on the TiO2 nanotubes (NTs) observed as the voltage increased. Fabricated photodetectors exhibited higher sensitivity to UV light as NiO surface dispersion increased. Electronic bandgap of TiO2 and that of NiO was determined as ~ 3.35 eV and ~ 3.80 eV, respectively. Introduction of NiO particles on well-ordered TiO2 NTs narrowed the bandgap of TiO2, and the difference between work functions of TiO2 and NiO produced sufficient built-in electric field to separate the electron–hole pairs. This led to an enhanced performance of NiO/TiO2 heterojunction photodetectors, which showed high values of responsivity (86 A/W), external quantum efficiency (292%), and detectivity (2.2 × 1010 Jones) under 365 nm UV light illumination. The valence and conduction band offsets at the interface of the NiO/TiO2 heterojunction were determined as ~ 1.54 eV and ~ 1.99 eV, respectively.
Feasibility study of recycled CRT glass on elastic and radiation shielding properties used as x-ray and gamma-ray shielding materials
Recycled glass derived from discarded cathode ray tubes (CRT) was used as a component for (70-x)CRT–30K2O–xBaO glass systems (where x = 0–20 mol%). Temperature dependence of ultrasonic wave velocities was carried out at 4 MHz frequency using pressure-controlled ultrasonic technique. It was found that the velocities decreased gradually as BaO content increased. However, sound velocities increased with increasing temperature. Then, both velocities were applied to estimate their elastic properties. Based on the obtained results, the elastic moduli and micro hardness of studied glasses increased with the amount of BaO and temperature, while their Poisson's ratio remained almost constant. Radiation shielding properties were investigated in terms of μm and HVL at photon energies of 74.23, 97.14, 122, 662, 1173, and 1332 keV by using narrow beam x-ray attenuation and transmission methods. Their theoretical values were also calculated by WinXCom program and compared with ferrite concrete. The results showed better radiation shielding properties for recycled CRT glass in comparison to ferrite concrete. Furthermore, the values obtained from the experiment in this study are in good agreement with the theoretical data.
Electronic structures and optical properties of doped CuInTe2 chalcopyrite materials: density functional calculations
The electronic structures and optical properties of CuInTe2 semiconductors doped with III impurities are comprehensively studied by the density functional theory within the exchange–correlation potential of Perdew–Burke–Ernzerhof generalised gradient approximation. The structural parameters are sensitive to the dopants. The doped CuInTe2 chalcopyrites remain direct band gap semiconductors with the reduced band gaps. In the presence of the impurities, the contributions from p states of dopants are additionally involved, responsible for the reduction of the band gaps. All doped samples display the optical anisotropies which can be applied in the second harmonic generation and optical parametric oscillator. The extension of the absorption range is achieved by substituting In atom with B, Al and Ga. Finally, this theoretical work establishes a broader understanding of the dopability of semiconductor sensitiser and recommends the electronic structures and optical properties for the solar cell applications.
Investigations on borate glasses within SBC-Bx system for gamma-ray shielding applications
This paper examines gamma-ray shielding properties of SBC-Bx glass system with the chemical composition of 40SiO2–10B2O3–xBaO–(45-x)CaO– yZnO– zMgO (where x = 0, 10, 20, 30, and 35 mol% and y = z = 6 mol%). Mass attenuation coefficient (μ/ρ) which is an essential parameter to study gamma-ray shielding properties was obtained in the photon energy range of 0.015–15 MeV using PHITS Monte Carlo code for the proposed glasses. The obtained results were compared with those calculated by WinXCOM program. Both the values of PHITS code and WinXCOM program were observed in very good agreement. The μ/ρ values were then used to derive mean free path (MFP), electron density (Neff), effective atomic number (Zeff), and half value layer (HVL) for all the glasses involved. Additionally, G-P method was employed to estimate exposure buildup factor (EBF) for each glass in the energy range of 0.015–15 MeV up to penetration depths of 40 mfp. The results reveal that gamma-ray shielding effectiveness of the SBC-Bx glasses evolves with increasing BaO content in the glass sample. Such that SBC-B35 glass has superior shielding capacity against gamma-rays among the studied glasses. Gamma-ray shielding properties of SBC-B35 glass were compared with different conventional shielding materials, commercial glasses, and newly developed HMO glasse. Therefore, the investigated glasses have potential uses in gamma shielding applications.
Enhanced bioactivity and antibacterial properties of anodized ZrO2 implant coatings via optimized nanoscale morphology and timed antibiotic release through PLGA overcoa
Surface modification of Zirconium (Zr) with Zirconia (ZrO2) nanotubes (NTs) was performed using a two-step electrochemical anodization to investigate the role of such a modified surface in apatite formation and the inhibition of bacterial growth on Zr implants. Pore size at the surface of the NT arrays was controlled, along with the NT length, by varying the 2nd-step anodizing time duration. Nearly four-fold changes in the pore size were achieved by varying the anodization at the second anodizing step. The apatite formation on the implant surfaces plays an important role in the osteointegration process, which can be greatly influenced by the morphology and crystalline structure of the surface. XRD analysis of the anodized surfaces identified a mixed phase of monoclinic and tetragonal ZrO2 NTs with the crystallite size decreasing with increased 2nd anodizing time duration. Surface roughness of the ZrO2 NTs decreased with an increase in anodizing time duration. The ZrO2 NTs with the largest pore sizes, and the smallest crystallite sizes (ZrO2-15 m) favoured the deposition of a Ca-rich compound on their surfaces following 24 days of soaking in SBF, and showed the highest apatite-forming ability among all studied samples. Antibacterial tests showed that the ZrO2-15 m sample exhibited antibacterial properties with 1log10 CFU/mL reduction of S. aureus and E. coli incubated in a buffer solution for 4 h. Loading the NT layer with antibacterial drug led to a complete inhibition of both bacterial species. The rate of drug release was slowed down by dip coating the drug loaded NTs in a PLGA solution. A higher number of dip-coating steps not only slowed down the release of the drug, it also led to a higher suppression of growth in both bacteria. Longer antibiotic exposure and optimized dosage of the drug released from ZrO2 NTs can therefore be managed by modifying the NT morphology and the number of PLGA dip-coating steps.
Tuning electronic structures and optical properties in CdSe/CdS Dot-in-rod colloidal nanostructures: Atomistic tight-binding theory
Using the atomistic tight-binding theory, in this study, the electronic structures and optical properties of CdSe/CdS dot-in-rod nanocrystals are modified by engineering the core and rod diameters. The ground electron states favor an s-like orbital, while the ground hole states are formed by light hole-like characteristics. The quantum confinement effect is attributed to the reduction in excitonic band gaps as the core and rod diameters increase. Changing the core and rod sizes produces excitonic band gaps across the visible light spectra. The highest oscillation strength, excitonic-binding energy, and dark-bright excitonic splitting are witnessed at a 3.0 nm CdSe core diameter. The oscillation strength, excitonic-binding energy, and dark-bright excitonic splitting decrease as the CdS rod diameters increase. This study highlights the importance of theoretically understanding and controlling the active materials’ structural parameters in optoelectronic technology.
First principles study in the electronic structures and optical properties of chalcogenide-doped AgInS2
The Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA) is adopted to simulate the electronic structures and optical properties of AgInS2 semiconductors with S substitution by chalcogenides. The chalcogenide-doped AgInS2 semiconductor can be synthesized at the normal conditions due to the formation energies. O and Se doping in AgInS2 remain the semiconductor with the narrow band gaps, while Te doping converts semiconductor to metal. In the presence of the impurities, the contributions from p states of chalcogenides are involved, accountable for the reduction of the band gaps. Using the reflectivity and absorption coefficients, the optical properties with extensive absorption range and low reflectivity are attained by incorporating AgInS2 semiconductors with chalcogenides. Finally, this theoretical work launches a broader understanding of the absorber materials and also predicts the natural properties as the alternative for the solar cell applications.
Enhanced bioactivity and antibacterial properties of anodized ZrO2 implant coatings via optimized nanoscale morphology and timed antibiotic release through PLGA overcoa
Atomistic effect of laterally and vertically growth shell on physical behaviours of CdSe/CdTe type-II core/crown and core/shell nanoplatelets: Tight-binding theory
Utilizing the atomistic tight-binding theory, the impact of the lateral and vertical potential confinement by the coated shell on the CdSe/CdTe core/crown and core/shell nanoplatelets (NPLs) is attained. The spatial charge separation and encapsulated shell have a noteworthy impact on the electronic structures and optical properties because of the type-II band profile. The reduced band gaps with the growing laterally and vertically passivated shell thicknesses are due to the quantum confinement phenomena. The optical band gaps adjusted across the visible light are achieved by the shell thickness change. The excitonic binding energies of CdSe/CdTe core/shell NPLs are larger than those of CdSe/CdTe core/crown NPLs. Thanks to the spatial charge separation, a shortening of the oscillation strengths is concomitant with an increase of the radiative lifetimes. Overall, this scientific research underlines the importance of the theoretical understanding and practical control by lateral and vertical confinement of heterostructure NPLs.
Achieving Bright Reddish-Orange Luminescence in CaSnO3 Ceramics through Doping Manipulation
The reddish-orange phosphors of rare-earth activator have attracted intense interest due to their applications in lighting and display devices, including plasma display panel, field emission display and white light diode. In this work, Eu-doped CaSnO3 phosphor materials were prepared and examined. Their X-ray diffraction patterns were used for lattice parameters calculations and show that there was no phase transformation in all doping conditions. XANES studies suggest the stabilization of Sn and Eu ions in 4+ and 3+ oxidation states in the prepared phosphors, respectively. A broad emission band, with a major peak at 614 nm upon excitation wavelength of 395 nm, was observed in the range of 550 to 730 nm at room temperature due to 5D0 → 7FJ transition of Eu3+ ions. The luminescent spectra of the samples showed the intense light emission in the red-orange light region.
Tunable electronic, optical and magnetic characteristics in Mn-doped inverted type-I ZnSe/CdSe core/shell nanocrystals: Atomistic tight-binding model
Employing the atomistic tight-binding theory and sp-d exchange interaction, Mn-doped ZnSe cores encapsulated by a CdSe thin and thick shell are examined as the functional of the applied magnetic fields. The spin-degenerate states are broken in the applied fields because of the sp-d exchange interaction. The electronic, optical and magnetic characteristics of Mn-doped inverted type-I ZnSe/CdSe core/shell nanocrystals are sensitive with the applied magnetic fields caused by the sp-d exchange interaction, while those depend on the shell thickness on account of the quantum confinement phenomena. The optical properties are enhanced in Mn-doped ZnSe/CdSe@Thick core/shell nanocrystals inside the high magnetic fields. For the validation, the calculated Zeeman splitting energies agree well with the experimental data. Overall, these determined materials combine the advantages of nanocrystals and magnetic ions, thus opening alternative opportunities for a wide-ranging applications in the forthcoming.
Tuning electronic structures and optical properties in CdSe/CdS Dot-in-rod colloidal nanostructures: Atomistic tight-binding theory
Using the atomistic tight-binding theory, in this study, the electronic structures and optical properties of CdSe/CdS dot-in-rod nanocrystals are modified by engineering the core and rod diameters. The ground electron states favor an s-like orbital, while the ground hole states are formed by light hole-like characteristics. The quantum confinement effect is attributed to the reduction in excitonic band gaps as the core and rod diameters increase. Changing the core and rod sizes produces excitonic band gaps across the visible light spectra. The highest oscillation strength, excitonic-binding energy, and dark-bright excitonic splitting are witnessed at a 3.0 nm CdSe core diameter. The oscillation strength, excitonic-binding energy, and dark-bright excitonic splitting decrease as the CdS rod diameters increase. This study highlights the importance of theoretically understanding and controlling the active materials’ structural parameters in optoelectronic technology.
Atomistic tight-binding investigations of Mn-doped ZnSe nanocrystal: Electronic, optical and magnetic characteristics
Using the atomistic tight-binding theory with sp-d exchange interaction, the electronic, optical and magnetic properties of Mn-doped ZnSe nanocrystals as a function of magnetic fields and diameters are attained. The magnetic field splits the spin-degenerate states because of the sp-d exchange interaction. The minor reduction of optical band gaps is realized with the increasing magnetic fields. The optical band gaps are significantly decreased with the increasing diameters due to the quantum confinement effect. With the increasing magnetic fields, Zeeman splittings are improved but g-factor values are reduced. The g-factor values are promoted with the increasing diameters. The calculated Zeeman splitting and exciton g-factor value reveal a good agreement with the experimental records. The magnetic field divides the optical spectra into two σ+ and σ− circularly polarized components. Overall, this study will assist the fundamental understanding of the magnetically-doped semiconductor nanocrystals which is valuable for spintronic applications.
A Comparative Study on the Parameter Identification of an Equivalent Circuit Model for an Li-ion Battery Based on Different Discharge Tests
An effective model of battery performance is important for battery management systems to control the state of battery and cell balancing. The second-order equivalent circuit model of a lithium-ion battery is studied in the present paper. The identification methods that include the multiple linear regression (MLR), exponential curve fitting (ECF) and Simulink design optimization tool (SDOT), were used to determine the model parameters. The aim of this paper is to compare the validity of the three proposed algorithms, which vary in complexity. The open circuit voltage was measured based on the pulse discharge test. The voltage response was collected for every 10% SOC in the interval between 0–100% SOC. The battery voltages calculated from the estimated parameters under the constant current discharge test and dynamic discharge tests for electric vehicles (ISO and WLTP) were compared to the experimental data. The mean absolute error and root mean square error were calculated to analyze the accuracy of the three proposed estimators. Overall, SDOT provides the best fit with high accuracy, but requires a heavy computation burden. The accuracy of the three methods under the constant current discharge test is high compared to other experiments, due to the nonlinear behavior at a low SOC. For the ISO and WLTP dynamic tests, the errors of MLR are close to that of SDOT, but have less computing time. Therefore, MLR is probably more suitable for EV use than SDOT.
Modulation of electronic and magnetic properties of MoX2 (X = S and Se) monolayer via mono- and co-transition metal dopants: Spin density functional theory
Using the spin density functional theory with Hubbard term (DFT + U) to account for exchange and correlation electronic effect, we study the electronic and magnetic properties of transition metal mono- and co-doped MoX2 (X = S and Se) monolayers. The electronic structures and magnetic properties of these monolayers are effectively modulated by the embedded transition metal atoms. The formation of the magnetism is caused by the double exchange mechanism, namely p-d and d-d hybridization. V, Cr and Co are the most energetically preferable substitutional dopants for these monolayers because of the lowest formation energies. Mn, Fe and Co doped-MoX2 (X = S and Se) and (Mo, Co, Co) Se2 monolayers are reflected as the half-metal behaviour with a perfect (100%) spin polarization at the Fermi level. Finally, the doped transition-metal dichalcogenide monolayers exhibiting the half metallic properties are hopefully proposed for the benefit of two-dimensional spintronic devices.
Influence of the rf power and oxygen content on structural, electrical, and optical properties of V2O5 thin films prepared via reactive radio frequency sputtering
Magnetoimpedance Biosensors and Real-Time Healthcare Monitors: Progress, Opportunities, and Challenges
A small DC magnetic field can induce an enormous response in the impedance of a soft magnetic conductor in various forms of wire, ribbon, and thin film. Also known as the giant magnetoimpedance (GMI) effect, this phenomenon forms the basis for the development of high-performance magnetic biosensors with magnetic field sensitivity down to the picoTesla regime at room temperature. Over the past decade, some state-of-the-art prototypes have become available for trial tests due to continuous efforts to improve the sensitivity of GMI biosensors for the ultrasensitive detection of biological entities and biomagnetic field detection of human activities through the use of magnetic nanoparticles as biomarkers. In this review, we highlight recent advances in the development of GMI biosensors and review medical devices for applications in biomedical diagnostics and healthcare monitoring, including real-time monitoring of respiratory motion in COVID-19 patients at various stages. We also discuss exciting research opportunities and existing challenges that will stimulate further study into ultrasensitive magnetic biosensors and healthcare monitors based on the GMI effect.
Cosmic Radiation Exposure of Aircraft Crew under the Impact of Geomagnetic Vertical Cutoff Rigidity: Case Study of International Flights from Suvarnabhumi Airport, Thailand
Inhibition of Mycobacterium tuberculosis InhA by 3-nitropropanoic acid
3-Nitropropanoic acid (3NP), a bioactive fungal natural product, was previously demonstrated to inhibit growth of Mycobacterium tuberculosis. Here we demonstrate that 3NP inhibits the 2-trans-enoyl-acyl carrier protein reductase (InhA) from Mycobacterium tuberculosis with an IC50 value of 71 μM, and present the crystal structure of the ternary InhA-NAD+-3NP complex. The complex contains the InhA substrate-binding loop in an ordered, open conformation with Tyr158, a catalytically important residue whose orientation defines different InhA substrate/inhibitor complex conformations, in the “out” position. 3NP occupies a hydrophobic binding site adjacent to the NAD+ cofactor and close to that utilized by the diphenyl ether triclosan, but binds predominantly via electrostatic and water-mediated hydrogen-bonding interactions with the protein backbone and NAD+ cofactor. The identified mode of 3NP binding provides opportunities to improve inhibitory activity toward InhA.
Structural and electronic properties of LiMnO2 doped with transition metals: A first-principles study
A spin density functional calculations of structural and electronic properties of LiMnO2 doped with several transition metals (Sc, V and Tc) are reported. The physical properties of LiMnO2 material are sensitive with the transition-metal dopants. Transition metal dopants enhance the lattice parameters and volumes, thus increasing the Li diffusion channel. The computations underscore that d orbitals of transition metals are located around the Fermi level. V doping in LiMnO2 demonstrates the enhancement in the electronic conductivity due to the volumetric expansion. Finally, these results deliver a valuable information for the transitionmetal doped LiMnO2 cathode materials to improve the performance of lithium batteries.
Extended Cosmic Ray Decreases with Strong Anisotropy after Passage of Interplanetary Shocks
The passage of an interplanetary shock and/or interplanetary coronal mass ejection often causes a rapid decrease in the Galactic cosmic-ray (GCR) flux, known as a Forbush decrease, followed by a recovery of the flux over some days. These local effects are of short duration and strongly rigidity dependent, with higher-rigidity particles exhibiting much weaker effects. In contrast, we present data for two events in which the cosmic-ray flux gradually decreased for about 1 week after shock passage, then recovering over the following week, with the highest anisotropy levels observed throughout Solar Cycle 24. These extended decreases have a weak rigidity dependence and are much more prominent in observations at higher cutoff rigidity, where the initial Forbush decrease is not clearly detected and other variations are generally weak, as we demonstrate using data from the Princess Sirindhorn Neutron Monitor at Doi Inthanon, Thailand with a cutoff rigidity of about 17 GV. We propose that these extended decrease events were initiated upon the passage of an interplanetary shock that inhibited the inflow of GCRs along the interplanetary magnetic field, possibly due to magnetic mirroring at the shock. We also discuss the general behavior of GCR anisotropy as observed at this high cutoff rigidity.
Dynamical Behavior of Two Interacting Double Quantum Dots in 2D Materials for Feasibility of Controlled-NOT Operation
Two interacting double quantum dots (DQDs) can be suitable candidates for operation in the applications of quantum information processing and computation. In this work, DQDs are modeled by the heterostructure of two-dimensional (2D) MoS2 having 1T-phase embedded in 2H-phase with the aim to investigate the feasibility of controlled-NOT (CNOT) gate operation with the Coulomb interaction. The Hamiltonian of the system is constructed by two models, namely the 2D electronic potential model and the (Formula presented.) matrix model whose matrix elements are computed from the approximated two-level systems interaction. The dynamics of states are carried out by the Crank–Nicolson method in the potential model and by the fourth order Runge–Kutta method in the matrix model. Model parameters are analyzed to optimize the CNOT operation feasibility and fidelity, and investigate the behaviors of DQDs in different regimes. Results from both models are in excellent agreement, indicating that the constructed matrix model can be used to simulate dynamical behaviors of two interacting DQDs with lower computational resources. For CNOT operation, the two DQD systems with the Coulomb interaction are feasible, though optimization of engineering parameters is needed to achieve optimal fidelity.
Modulation of electronic and magnetic properties of MoX2 (X = S and Se) monolayer via mono- and co-transition metal dopants: Spin density functional theory
Using the spin density functional theory with Hubbard term (DFT + U) to account for exchange and correlation electronic effect, we study the electronic and magnetic properties of transition metal mono- and co-doped MoX2 (X = S and Se) monolayers. The electronic structures and magnetic properties of these monolayers are effectively modulated by the embedded transition metal atoms. The formation of the magnetism is caused by the double exchange mechanism, namely p-d and d-d hybridization. V, Cr and Co are the most energetically preferable substitutional dopants for these monolayers because of the lowest formation energies. Mn, Fe and Co doped-MoX2 (X = S and Se) and (Mo, Co, Co) Se2 monolayers are reflected as the half-metal behaviour with a perfect (100%) spin polarization at the Fermi level. Finally, the doped transition-metal dichalcogenide monolayers exhibiting the half metallic properties are hopefully proposed for the benefit of two-dimensional spintronic devices.
Electronic and magnetic properties of MoTe2monolayer doped with single and double transition metals: Spin density functional theory
The spin density functional computations are exploited to determine the electronic and magnetic properties of MoTe2 monolayer doped with single and double transition metal atoms (V, Cr, Mn, Fe and Co). These properties are sensitive with the types and numbers of the doping transition metals. The semiconductors with narrow band gaps are shown in Cr and Co single-doped MoTe2 monolayer. V and Mn single-doped MoTe2 monolayer are metal. Fe single-doped MoTe2 monolayer reveals the half-metallic behaviours with a 100% spin polarization. V and Co provide the first-two lowest formation energies and are used for the co-doping studies. MoTe2 monolayers simultaneously doped with two Co are characterized as half metal, while the others are metal. The p-d and d-d hybridization around the Fermi level introduce the magnetism, called double exchange mechanism.
Electronic structures and optical characteristics of CdSbulk/CdSe nanoshells and CdSbulk/CdSe/CdS quantum-well nanoshells: Atomistic tight-binding computations
The nanoshell architectures demonstrate the unique characteristics for the promising optical gain medium and lasing applications; this is investigated here using the atomistic tight-binding model. The electronic and optical characteristics of CdSbulk/CdSe nanoshells and CdSbulk/CdSe/CdS quantum-well nanoshells with experimentally synthesized structures are determined. The atomistic signatures are sensitive with nanoshell architectures and thickness of CdSe layer. The optical band gaps become narrow with the increasing CdSe layer thicknesses due to the large quantum-confinement volume. The optical band gaps of the tight-binding theory are in the excellent consistency with the experimental observation. Encapsulating CdSe layers on CdSbulk/CdSe nanoshells mainly promote the optical properties. The electron-hole pair is comfortably generated in CdSbulk/CdSe/CdS quantum-well nanoshells with large CdSe layers. The enhancement of stokes shift and radiative lifetimes is informed with the increasing CdSe layer thicknesses. The stokes shift and radiative lifetimes of CdSbulk/CdSe/CdS quantum-well nanoshells are greater than those of CdSbulk/CdSe nanoshells.
Portable multispectral fluorometer for determination of formalin in food samples using nitrogen-doped carbon dots as the fluorescence probe
In this work, we developed a portable multispectral fluorometer for determining formalin (FA). We used nitrogen-doped carbon dots (N-CDs) as the fluorescence probe, based on right-angle fluorescence spectrometry with twin excitation high-power light emitting diode sources. The multispectral spectroscopy sensor was used as a detector for fluorescence intensity. The fluorescence intensity values were displayed from 0 to 65535 a.u. The FA determination results show a linear relationship in the FA concentration range of 10-75 mg L−1 with r2 = 0.9908. The limit of detection (LOD) was 2.09 mg L−1 (calculated from 3SDblank/slope (n = 3)). In addition, the percentage of relative errors compared with the standard method and standard instrument shows less than 10 percent. The performance of a portable multispectral fluorometer in actual samples exhibited no significant difference compared to the validation instrument results. Therefore, the development of a portable multispectral fluorometer can be used as a fluorometer, and the measurement performance is comparable to a standard fluorescence spectrometer.
Technical Assessment of Reusing Retired Electric Vehicle Lithium-Ion Batteries in Thailand
A rapid growth in electric vehicles has led to a massive number of retired batteries in the transportation sector after 8–10 years of use. However, retired batteries retain over 60% of their original capacity and can be employed in less demanding electric vehicles or stationary energy storage systems. As a result, the management of end-of-life electric vehicles has received increased attention globally over the last decade due to their environmental and economic benefits. This work presents knowledge and technology for retired electric vehicle batteries that are applicable to the Thai context, with a particular focus on a case study of a retired lithium-ion battery from the Nissan X-Trail Hybrid car. The disassembled battery modules are designed for remanufacturing in small electric vehicles and repurposing in energy storage systems. The retired batteries were tested in a laboratory under high C-rate conditions (10C, 20C, and 30C) to examine the limitations of the batteries’ ability to deliver high current to electric vehicles during the driving operation. In addition, the electric motorcycle conversion has also been studied by converting the gasoline engine to an electric battery system. Finally, the prototypes were tested both in the laboratory and in real-world use. The findings of this study will serve as a guideline for the sorting and assessment of retired lithium-ion batteries from electric vehicles, as well as demonstrate the technical feasibility of reusing retired batteries in Thailand.
Theoretical study on structural, electronic, transport and thermoelectric properties of Si/Ge doped graphene
First-principles simulations are used in this study to show the structural, electronic, transport, and thermoelectric features of silicon and germanium-doped monolayer graphene. We employed a supercell of 2 × 2 × 1 graphene that contains 8 C atoms. One C atom was substituted by Si/Ge at a doping concentration of 12.5 %. The results obtained show that the band gap of pure graphene may be effectively opened and converted into a direct bandgap semiconductor material by replacing the C atom with Si/Ge atoms. Phonon dispersion provides a representation of the dynamical stability of all three structures. Graphene's thermal conductivity is also decreased when heteroatoms are added. Additionally, the Seebeck coefficient, the power factor, the electrical conductivity, and the figure of merit of pure, silicon, and germanium-doped graphene were investigated. This study offers a theoretical basis for using a heteroatom-doping process to improve the performance of graphene's electronic, transport, and thermoelectric characteristics.
Response function and photon interaction of LaBr3:Ce and BGO scintillation detectors by Monte Carlo simulation
This work aims to investigate the response function and photon interaction of the LaBr3:Ce and BGO scintillation detectors using the FLUKA Monte Carlo simulation software. To improve the realism of detectors, the DETGEB card was used to activate the gaussian energy broadening (GEB) function. The GEB parameters of both detectors were obtained by fitting a nonlinear curve to the relation between FWHM and gamma-ray energy. The energy resolution (R), peak-to-Compton ratio (PCR), peak-to-total ratio (PTR), and full-energy peak efficiency (FEPE) of both detectors were investigated by simulation and experiment at different gamma-ray energy obtained from 133Ba, 137Cs, and 60Co sources. The simulated spectra of those radioisotopes were found to agree with the actual spectra. The results found that the R, PCR, and FEPE values of the LaBr3:Ce and BGO detectors tend to decrease as energy increases. Moreover, the total atomic cross-section (��,�), effective atomic number (Zeff) and effective electron density (Neff) of both crystals was investigated by FLUKA and compared with the XCOM theoretical program covering an energy range of 15 keV to 15 MeV. The simulated results of the ��,�, Zeff, and Neff are in excellent agreement with the theoretical ones. The GEB parameters obtained from this study will improve the simulation performance of LaBr3:Ce and BGO detectors in investigating the gamma-ray response and shielding properties of materials.
Development of lectin-based lateral flow assay for fucosylated alpha-fetoprotein
Fucosylated alpha-fetoprotein (AFP-L3) is a more specific and sensitive biomarker for early diagnosis of hepatocellular carcinoma (HCC) than only the alpha-fetoprotein (AFP) level. Rapid and simple detection of AFP-L3 level greatly facilitates the early detection as well as the treatment of HCC, resulting in the reduction of mortality. Here, we developed a rapid and sensitive lateral flow assay (LFA) using lectin Lens culinaris agglutinin (LCA), which has a specific affinity to AFP-L3 fraction of AFP, as a biorecognition element for determination of the fucosylation of AFP. The assay is based on a sandwich format performed on a lateral flow test strip. LCA was immobilized on the membrane as a test line (T). Quantitative detection of AFP-L3 was achieved by measuring the green color intensity of captured gold nanoparticle conjugates on the T and control line (C) utilizing an in-house test strip reader. The calculated absorbance obtained by the green color intensity signals proportionally increased with AFP concentrations. The developed lectin-based LFA provided a detection limit of 0.8 ng/mL for AFP with a linear range between 1.5 and 160.0 ng/mL within an assay time of 10 min. Recoveries between 74.5% and 113.2% with relative standard deviations of 5.2%-8.7% for measuring spiked human serum were also achieved. The results reveal that the proposed assay offers a rapid, sensitive, and specific method, which is useful for development in point-of-care testing for early detection and treatment of HCC.
A first-principles study of structural, electronic and transport properties of aluminium and phosphorus-doped graphene
First-principles simulations are utilised for computing the structural, electronic, and transport characteristics of pure graphene and graphene doped with aluminium and phosphorus. The results demonstrate that by substituting Al and P atoms for carbon atoms in graphene, the material's band gap may be effectively opened. When Al or P atom replaces a carbon atom, a notable band gap value of 1.49 eV or 0.40 eV has been detected. Additionally, the thermal conductivity, Seebeck coefficient, carrier concentration, power factor, electrical conductivity, and dimensionless figure of merit of pure graphene, aluminium and phosphorus-doped graphene are examined. Our study presents the theoretical basis for using a doping mechanism with heteroatoms to improve graphene's electronic and transport properties. Al/P doped graphene has the potential to significantly improve thermoelectric efficiency due to its electronic properties and low thermal conductivity.
Determination of X-ray and gamma-ray shielding capabilities of recycled glass derived from deteriorated silica gel
We determined the radiation shielding properties for 10CaO–xPbO–(90-x) deteriorated silica gel (DSG) glass system (x = 20, 25, 30, 35, 40, and 45 mol.%). The mass attenuation coefficient (MAC) has been estimated at photon energies of 74.23, 97.12, 122, 662, 1173, and 1332 keV using a narrow beam X-ray attenuation and transmission experiment, the XCOM program, and a PHITS simulation. The obtained MAC values were applied to estimate the half value layer (HVL), mean free path (MFP), effective atomic number, and effective electron density. Results show that the MAC value of the studied glasses ranges between 0.0549 and 1.4415 cm2/g, increases with the amount of PbO, and decreases with increasing photon energy. The HVL and MFP values decrease with increasing PbO content and increase with increasing photon energy. The recycled glass, with the addition of PbO content (20–45 mol.%), exhibited excellent radiation shielding capabilities compared to standard barite and ferrite concretes and some glass systems. Moreover, the experimental radiation shielding parameters agree with the XCOM and PHITS values. This study suggests that this new waste-recycled glass is an effective and cost-saving candidate for X-ray and gamma-ray shielding applications.
Effect of dual Nitrogen doping on the electronic, thermodynamic, transport and thermoelectric properties of graphene
Electronic, thermodynamic, transport, and thermoelectric properties of pristine graphene (C8) and graphene doped with dual nitrogen (N) atoms in three different configurations were theoretically studied. All three configurations display a direct band gap and are n-type semiconductors. Notably, at room temperature, N3-doped graphene has a greater Seebeck coefficient (S) than C8, although N1 and N2 have lower S values. Furthermore, the power factor (PF) for all three structures rapidly increases, especially at high temperatures, with C8's PF decreasing at 300 K. For N1, N2, and N3, the electronic thermal conductivity ( follows the Wiedemann-Franz rule, increasing with increasing temperature. Due to N defect-induced heat transfer scattering, lattice thermal conductivity ( diminishes exponentially with temperature. The figure of merit (ZT) for N3 doping peaks at 550 K, outperforming N1 and N2 by a large margin (103-106 times) and then drops at higher temperatures due to electronic thermal conductivity impacts.
Numerical investigation on performance improvement of CuO/TiO2 heterojunctions for applications in sunlight-driven photodetectors and photocatalysts
The performance improvement of CuO/TiO2 heterojunctions was investigated to contribute to the understanding of factors influencing the performance of the heterojunctions and their potential applications in sunlight-driven photodetectors and photocatalysts. By using optimal parameters (TiO2 (CuO)’s thickness of 5 µm (60 nm), acceptor (donor) doping concentration of 1017 cm−3 (1018 cm−3), required interface defect of 1013 cm−3, and under AM 1.5G illumination at 27 °C and 0 V bias voltage, the device achieved a photocurrent density of 13 mA/cm2, a photoresponsivity of 3.25 A/W, a detectivity of 1.8 × 1014 Jones, and effectiveness across UVA and visible light. At temperatures approaching 300 °C, the CuO/TiO2 device maintained its high photoresponsivity and efficiency, indicating its suitability for applications in high-temperature environments, such as hydrogen production through photocatalysis. The results suggest that the devices have the potential to be utilized in sunlight-driven optoelectronic and photocatalyst industries, offering cost-effectiveness and high efficiency.
