cBodanov emrs2012
•
1 like•319 views
This study systematically analyzed the effect of local ordering of B-cations (Zr and Ti) on the electronic, optical, and piezoelectric properties of PbZrxTi1-xO3 (PZT) using density functional theory calculations. The most stable structure found was a tetragonal phase with P4mm symmetry. Other stable phases included a polar orthorhombic phase and a non-polar triclinic phase. Analysis showed that different arrangements of B-cations led to variations in the electronic structure, polarization, and piezoelectric response of the materials. In particular, large piezoelectric coefficients e15 and e33 were associated with specific planar and axial arrangements of
Report
Share
Report
Share
Download to read offline
Recommended
Lv3520212024
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Indium Doped Zinc Oxide Thin Films: Effect on Structural, Optical and Electri...
This document summarizes research on indium-doped zinc oxide thin films deposited using spray pyrolysis. Key findings include:
1) XRD analysis showed the films were polycrystalline and doping led to a decrease in average grain size and a reorientation of crystal planes.
2) Optical band gap increased from 3.06 eV to 3.6 eV with doping due to the Burstein-Moss effect. Transmittance remained above 80% in the visible region.
3) Electrical resistivity decreased from 45.07 Ω-cm in undoped films to a minimum of 0.1 Ω-cm with doping, increasing conductivity. The highest figure of merit
Optical and Impedance Spectroscopy Study of ZnS Nanoparticles
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
Dielectric, Electric and Thermal Behavior of La3+ doped Co-Zn Nanoferrite
Dielectric, Electric and Thermal properties of rare earth La3+ material doped in Co0.5Zn0.5 Lax Fe(2- x)O4 (where x=0.025, 0.050, 0.075, 0.100, 0.125) reaction nanocrystalline ferrites were synthesized by sol-gel auto combustion method. The electric, dielectric constant and Thermal properties were investigated. The dielectric constants and dielectric loss of the samples was observed between the 100Hz and 5 MHz. The resistivities of the prepared samples were measured from 0 Volt to 550 Volts at the constant temperature 2000C using the Two Probe method. The Thermal properties were characterized by Thermo Gravimetric and Differential Thermal Analysis (TGDTA).
M McCarthy ALD2016
This document summarizes research into depositing electron transport layers (ETLs) for perovskite solar cells using atomic layer deposition (ALD) at low temperatures. TiO2 and SnO2 were deposited as ETLs using thermal ALD at 185°C with and without a plasma pre-clean treatment. XRD analysis found the films were amorphous. XPS showed doping TiO2 with Al2O3 did not change the Ti oxidation state. A plasma pre-clean improved conductivity for TiO2 and SnO2. Wetting of the perovskite layer differed between ETLs, with O2 plasma SnO2 displaying the best wettability despite not having the highest conductivity. Further
Al03402180221
The document studies the dielectric properties of irradiated and non-irradiated muga silk fibers in the presence of oxygen at elevated temperatures. It finds that the dielectric constant and loss are significantly higher for both raw and irradiated fibers in oxygen compared to air, and an additional peak arises in the dielectric constant-temperature curve in oxygen. Specifically, at 323K the dielectric constant is 4.96 and dielectric loss is 0.1 for irradiated fiber in oxygen, compared to 2.31 and 0.231 respectively in air. For non-irradiated fiber, the values are 67.49 and 1.9 in oxygen versus 4.96 and 0.496 in air. The presence of oxygen decreases degradation
Fabrication of semiconductor materials by using electrospinning
The document discusses electrospinning techniques for fabricating semiconductor nanofibers. It begins with an introduction to semiconductors and electrospinning. It then explains how electrospinning parameters like solution concentration and applied voltage affect fiber morphology. Different electrospinning setups and collection methods are also reviewed. Examples are given of using electrospinning to produce gallium nitride and zinc oxide nanofibers for applications in transistors, photodetectors, and other devices. In conclusion, electrospinning provides a simple way to fabricate high quality semiconductor nanofibers for various applications.
Ab Initio Study of the Electronic and Phonon Band Structure Of the Mixed Vale...
This document summarizes an ab initio study of the electronic band structure and phonon dispersion of silver oxide (AgO) using density functional theory calculations. The LDA+U method predicted AgO to be a semimetal, while the Hartree-Fock calculation predicted a semiconductor with an indirect bandgap of 1.53 eV, consistent with experiments. Phonon calculations showed small splitting between longitudinal and transverse optical modes for higher oxygen vibrations, explaining why Raman spectroscopy could not observe these modes. The study provides insights into the electronic properties and vibrational behavior of the mixed valence silver oxide.
Recommended
Lv3520212024
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Indium Doped Zinc Oxide Thin Films: Effect on Structural, Optical and Electri...
This document summarizes research on indium-doped zinc oxide thin films deposited using spray pyrolysis. Key findings include:
1) XRD analysis showed the films were polycrystalline and doping led to a decrease in average grain size and a reorientation of crystal planes.
2) Optical band gap increased from 3.06 eV to 3.6 eV with doping due to the Burstein-Moss effect. Transmittance remained above 80% in the visible region.
3) Electrical resistivity decreased from 45.07 Ω-cm in undoped films to a minimum of 0.1 Ω-cm with doping, increasing conductivity. The highest figure of merit
Optical and Impedance Spectroscopy Study of ZnS Nanoparticles
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
Dielectric, Electric and Thermal Behavior of La3+ doped Co-Zn Nanoferrite
Dielectric, Electric and Thermal properties of rare earth La3+ material doped in Co0.5Zn0.5 Lax Fe(2- x)O4 (where x=0.025, 0.050, 0.075, 0.100, 0.125) reaction nanocrystalline ferrites were synthesized by sol-gel auto combustion method. The electric, dielectric constant and Thermal properties were investigated. The dielectric constants and dielectric loss of the samples was observed between the 100Hz and 5 MHz. The resistivities of the prepared samples were measured from 0 Volt to 550 Volts at the constant temperature 2000C using the Two Probe method. The Thermal properties were characterized by Thermo Gravimetric and Differential Thermal Analysis (TGDTA).
M McCarthy ALD2016
This document summarizes research into depositing electron transport layers (ETLs) for perovskite solar cells using atomic layer deposition (ALD) at low temperatures. TiO2 and SnO2 were deposited as ETLs using thermal ALD at 185°C with and without a plasma pre-clean treatment. XRD analysis found the films were amorphous. XPS showed doping TiO2 with Al2O3 did not change the Ti oxidation state. A plasma pre-clean improved conductivity for TiO2 and SnO2. Wetting of the perovskite layer differed between ETLs, with O2 plasma SnO2 displaying the best wettability despite not having the highest conductivity. Further
Al03402180221
The document studies the dielectric properties of irradiated and non-irradiated muga silk fibers in the presence of oxygen at elevated temperatures. It finds that the dielectric constant and loss are significantly higher for both raw and irradiated fibers in oxygen compared to air, and an additional peak arises in the dielectric constant-temperature curve in oxygen. Specifically, at 323K the dielectric constant is 4.96 and dielectric loss is 0.1 for irradiated fiber in oxygen, compared to 2.31 and 0.231 respectively in air. For non-irradiated fiber, the values are 67.49 and 1.9 in oxygen versus 4.96 and 0.496 in air. The presence of oxygen decreases degradation
Fabrication of semiconductor materials by using electrospinning
The document discusses electrospinning techniques for fabricating semiconductor nanofibers. It begins with an introduction to semiconductors and electrospinning. It then explains how electrospinning parameters like solution concentration and applied voltage affect fiber morphology. Different electrospinning setups and collection methods are also reviewed. Examples are given of using electrospinning to produce gallium nitride and zinc oxide nanofibers for applications in transistors, photodetectors, and other devices. In conclusion, electrospinning provides a simple way to fabricate high quality semiconductor nanofibers for various applications.
Ab Initio Study of the Electronic and Phonon Band Structure Of the Mixed Vale...
This document summarizes an ab initio study of the electronic band structure and phonon dispersion of silver oxide (AgO) using density functional theory calculations. The LDA+U method predicted AgO to be a semimetal, while the Hartree-Fock calculation predicted a semiconductor with an indirect bandgap of 1.53 eV, consistent with experiments. Phonon calculations showed small splitting between longitudinal and transverse optical modes for higher oxygen vibrations, explaining why Raman spectroscopy could not observe these modes. The study provides insights into the electronic properties and vibrational behavior of the mixed valence silver oxide.
APS march meeting 2015
This document summarizes an ARPES and SPE-LEEM study on supported, suspended, and twisted bilayer MoS2. The study directly measures the MoS2 band structure using SPE-LEEM to study the band gap transition and role of interlayer coupling in monolayer, bilayer, and twisted bilayer MoS2. It also studies the substrate effect by examining suspended MoS2. Preliminary results on effective mass and spin-orbit splitting are also presented.
synthesis of doped chromium oxide nanoparticles
The document summarizes a research paper on the size-dependent optical properties of zinc-doped chromium oxide (Cr2O3) nanoparticles. It includes an introduction, methods used to prepare and analyze the nanoparticles, results of the analysis showing decreasing band gap and changing refractive index with decreasing particle size, and conclusions about the nanoparticles exhibiting quantum confinement effects and potential applications in solar cells and optoelectronic devices.
Graphene presentation
Graphene is a two-dimensional material made of a single layer of carbon atoms arranged in a honeycomb lattice. It was awarded the 2010 Nobel Prize in Physics. Graphene has highly desirable properties such as high conductivity, strength, and thinness. Unlike silicon, electrons in graphene behave like massless particles and can flow freely without an energy barrier. This gives graphene potential to revolutionize electronics by allowing much faster and more efficient devices.
Research issues in graphene field effect transistor
This document discusses research issues in graphene field effect transistors (GFETs). GFETs use graphene as the channel material rather than silicon. Graphene has several advantageous properties like high electron mobility and ambipolar conduction. However, graphene lacks a bandgap which prevents it from being used as a semiconductor. Several methods have been proposed to induce a bandgap like using graphene nanoribbons or bilayer graphene with an electric field. Optimizing GFET performance further requires increasing carrier mobility and decreasing contact resistance between graphene and metal electrodes. Addressing these issues could enable using GFETs in applications like radio frequency amplifiers and mixers.
Seminar ppt
This document summarizes a seminar on magnetic nanocomposites. It discusses how nanocomposites have particles mixed at the nanoscale, including magnetic nanocomposites containing ferromagnetic particles. The history of magnetic nanocomposites is reviewed, from early amorphous alloys to developments in the 1980s-1990s of alloys like FINEMET, NANOPERM, and HITPERM. Recent developments discussed include core-shell nanoparticles, colloidal crystals, mesoporous nanocomposites, and functional polymers. Applications mentioned are using magnetic fields to destroy tumor cells, transformers, and DC-DC power converters. Challenges remaining are controlled synthesis, understanding mechanisms, cost, toxicity
Hebatalrahman nanotreatment
The document describes a laser indirect exposure method for treating nanomaterials. The method involves dipping powder materials in a transparent plastic to allow laser beams to pass through without being absorbed by the plastic. This indirectly exposes the powder to laser irradiation, which improves the mechanical properties of the materials. After exposure, an organic solvent is used to separate the treated nanomaterials from the dissolved plastic. Testing showed that laser treatment led to changes in Raman spectra and increased hardness of the treated materials. The method improves properties through laser energy absorption without causing economic losses or pollution.
Power Genertaion using Nanofiber
This document discusses using nanofibers to generate power from tires. Piezoelectric nanofibers like PZT-5A and PVDF could be embedded in tires to convert the mechanical energy from tire deformation into electrical energy. When stress is applied to these nanofibers due to tire movement or changes in pressure, a charge is produced through the piezoelectric effect. It is estimated these nanofibers could achieve a 25% energy conversion efficiency and generate several milliwatts of power. The document also notes that sensors may be needed to avoid resonance issues from the natural frequencies of the materials not matching tire frequencies.
Semiconductor Nanomaterials
This document discusses semiconductor nanomaterials and their applications in energy and the environment. It begins by defining semiconductors and discussing how their properties change at the nanoscale due to quantum effects. Common semiconductor materials include silicon, which is used in most electronics, as well as gallium arsenide and others. The document then covers topics such as doping to create n-type and p-type semiconductors, direct and indirect bandgaps, recombination processes, and quantum structures including quantum wells, wires and dots. Nanocrystals were first discovered in the 1980s and exhibit size-dependent optical properties due to quantum confinement effects.
B0460612
This document reports on the synthesis and characterization of copper indium disulfide (CuInS2) nanoparticles. CuInS2 nanoparticles were prepared by a solid state melt growth process under vacuum. X-ray diffraction analysis confirmed the formation of a chalcopyrite crystal structure in the as-prepared sample. Field emission scanning electron microscopy images showed an increase in nanoparticle size after annealing the sample at 200°C. Energy dispersive X-ray analysis demonstrated that the elemental composition of copper, indium, and sulfur was maintained close to the intended stoichiometric ratio.
EFFECT OF ULTRAVIOLET RADIATION ON STRUCTURAL PROPERTIES OF NANOWIRES
Copper nanowires were prepared through electrochemical template synthesis using Nucleopore polycarbonate membranes having nominal pore sizes of 800nm and 15nm diameter. The 800nm and 15nm nanowires thus grown were viewed under SEM and TEM respectively, while their FCC crystallographic structure was confirmed through X-ray and electron diffraction patterns. The X-ray diffraction peaks indicated strong texturing for (200). The texturing was found to reduce significantly upon exposure to ultraviolet radiation.
Electrospinning of nanofibers 2
The document discusses nanofibers and their production via electrospinning. It defines nanofibers as fibers with diameters less than 1000 nm and notes their small size compared to human hair. The document then explains the electrospinning process, where a high voltage draws thin fibers from a liquid source. Key aspects reviewed include the Taylor cone formation, bending instability that reduces fiber diameters, and parameters that impact electrospinning. Finally, it outlines early nanofiber production at UPLB involving various polymers like PCL, PVC and PLGA.
IRJET- The Ab Initio Study of Electronic and Optical Properties of CH3NH3ZnI3...
This document summarizes an ab initio study of the electronic and optical properties of the perovskite solar cell material CH3NH3ZnI3. Key findings include:
1) CH3NH3ZnI3 has a direct bandgap of 0.34 eV, which is significantly smaller than the 1.53 eV bandgap of the commonly used CH3NH3PbI3 material.
2) X-ray diffraction data analysis showed that CH3NH3ZnI3 retains the original cuboctahedral crystal structure of CH3NH3PbI3.
3) Optical property calculations predicted CH3NH3ZnI3 would absorb electromagnetic radiation in the far UV region and
Dielectric properties of Ni-Al nano ferrites synthesized by citrate gel method
Ni–Al ferrite with composition of NiAlxFe2-xO4 (x=0.2, 0.4 0.6, and 0.8, ) were prepared by citrate gel method. The Dielectric Properties for all the samples were investigated at room temperature as a function of frequency. The Dielectric constant shows dispersion in the lower frequency region and remains almost constant at higher frequencies. The frequency dependence of dielectric loss tangent (tanδ) is found to be abnormal, giving a peak at certain frequency for mixed Ni-Al ferrites. A qualitative explanation is given for the composition and frequency dependence of the dielectric loss tangent.
Study of doped chromiun oxide nanoparticle
This document outlines a study on the synthesis and characterization of doped Cr2O3 nanoparticles. It will investigate doping Cr2O3 nanoparticles with elements like Fe, ZnO, and Co using microwave synthesis and sol-gel methods. Characterization of the structural, electrical, and optical properties of the doped nanoparticles will be conducted using techniques like XRD, SEM, and FTIR. The study aims to better understand how doping affects the properties of Cr2O3 nanoparticles compared to the bulk material. A timeline is provided outlining the literature review, experimental work, characterization, drafting and final submission over a 5 month period.
Jean ISDRS 2007
1. The document discusses metal-molecule-GaAs devices using self-assembled monolayers of redox-active molecules.
2. Three molecules - octadecanethiol, a ligand, and a ruthenium complex - were deposited on GaAs and tested.
3. Current-voltage measurements showed higher current densities in the molecular devices compared to a control metal-semiconductor device, and thermionic and thermionic-field emission models were found to fit the data.
Graphene ppt
The document discusses graphene, a one-atom thick sheet of carbon atoms arranged in a honeycomb lattice. Graphene was discovered in 2003 when researchers found thin flakes of it on scotch tape. It has remarkable mechanical, thermal, electrical, and optical properties such as being very strong yet flexible, highly conductive, and nearly transparent. These properties give graphene potential applications in areas like integrated circuits, water purification, gas sensors, transistors, solar cells, and flexible displays. However, widespread use of graphene is limited by challenges in production costs, quality control, and the lack of a bandgap.
Synthesis & Heating Mechanisms of Magnetic Nanoparticles in Hyperthermia Trea...
This document summarizes research on synthesizing magnetic nanoparticles for use in hyperthermia cancer treatment. It discusses two samples of magnesium ferrite nanoparticles synthesized via co-precipitation at different temperatures and concentrations. Characterization with XRD and VSM showed the samples had hexagonal structure and increasing magnetization with higher sintering temperature. In hyperthermia experiments, both samples saw increased temperature over time with applied alternating magnetic fields, with better results at higher frequencies above 500 kHz needed to effectively treat cancer.
Fabrication and electrical characteristic of quaternary ultrathin hf tiero th...
This document describes the fabrication and electrical characterization of quaternary ultrathin HfTiErO thin films grown by RF sputtering for MOS devices. HfTiErO thin films with different Ti and Er contents were deposited on silicon substrates. The films were annealed at 500°C and 700°C. Atomic force microscopy showed the surface roughness decreased with annealing. X-ray photoelectron spectroscopy analysis showed the chemical compositions. MOS capacitors were fabricated and capacitance-voltage measurements showed the annealed films at 500°C had improved electrical properties like higher dielectric constant. The HfTiErO film with composition HfTi6Er4O annealed at 500°C achieved the best electrical performance of the
Global-13
The document summarizes research on modeling the temperature dependence of the inverse dielectric susceptibility in KDP-type crystals. The authors used a four-particle cluster model Hamiltonian with third- and fourth-order phonon anharmonic interaction terms. They derived expressions for the renormalized soft mode frequency and inverse dielectric susceptibility using the double-time temperature dependent Green's function method. By fitting model parameters, they evaluated the temperature dependence of the soft mode frequency and inverse dielectric susceptibility for KDP crystals in the paraelectric phase. Their theoretical results agreed well with experimental data from other studies.
Vortex Polarization Instabilities in PbTiO3 Nanowires
This document discusses polarization instabilities in PbTiO3 nanowires based on density functional theory computations. The key findings are:
1) Vortex or non-rectilinear polarization states are found to be the equilibrium polarization configuration in TiO2-terminated PbTiO3 nanowires above a critical size of 1.6 nm.
2) Four possible switchable polarization states are identified for PbTiO3 nanowires: clockwise/counter-clockwise vortex and positive/negative axial polarization.
3) The instability towards vortex polarization is associated with imaginary zone-center phonon eigenvectors, analogous to a soft optical phonon mode driving the ferroelectric transition in the bulk.
Polarization, strain induced phase transitions and dielectric response in ult...
Ultrathin PbTiO3 nanowires can have switchable straight or vortex polarization configurations depending on their termination and strain. PbO termination and tensile strain favor straight polarization while TiO2 termination and compressive strain favor vortex polarization. The static and optical dielectric permittivity is significantly enhanced along the axial direction but reduced in other directions due to depolarizing fields. Nanowires with vortex polarization are expected to have particularly large dielectric permittivity.
Electric properties
Simple description with polarisation curves and applications of dielectrics, paraelectrics and ferroelectrics.
More Related Content
What's hot
APS march meeting 2015
This document summarizes an ARPES and SPE-LEEM study on supported, suspended, and twisted bilayer MoS2. The study directly measures the MoS2 band structure using SPE-LEEM to study the band gap transition and role of interlayer coupling in monolayer, bilayer, and twisted bilayer MoS2. It also studies the substrate effect by examining suspended MoS2. Preliminary results on effective mass and spin-orbit splitting are also presented.
synthesis of doped chromium oxide nanoparticles
The document summarizes a research paper on the size-dependent optical properties of zinc-doped chromium oxide (Cr2O3) nanoparticles. It includes an introduction, methods used to prepare and analyze the nanoparticles, results of the analysis showing decreasing band gap and changing refractive index with decreasing particle size, and conclusions about the nanoparticles exhibiting quantum confinement effects and potential applications in solar cells and optoelectronic devices.
Graphene presentation
Graphene is a two-dimensional material made of a single layer of carbon atoms arranged in a honeycomb lattice. It was awarded the 2010 Nobel Prize in Physics. Graphene has highly desirable properties such as high conductivity, strength, and thinness. Unlike silicon, electrons in graphene behave like massless particles and can flow freely without an energy barrier. This gives graphene potential to revolutionize electronics by allowing much faster and more efficient devices.
Research issues in graphene field effect transistor
This document discusses research issues in graphene field effect transistors (GFETs). GFETs use graphene as the channel material rather than silicon. Graphene has several advantageous properties like high electron mobility and ambipolar conduction. However, graphene lacks a bandgap which prevents it from being used as a semiconductor. Several methods have been proposed to induce a bandgap like using graphene nanoribbons or bilayer graphene with an electric field. Optimizing GFET performance further requires increasing carrier mobility and decreasing contact resistance between graphene and metal electrodes. Addressing these issues could enable using GFETs in applications like radio frequency amplifiers and mixers.
Seminar ppt
This document summarizes a seminar on magnetic nanocomposites. It discusses how nanocomposites have particles mixed at the nanoscale, including magnetic nanocomposites containing ferromagnetic particles. The history of magnetic nanocomposites is reviewed, from early amorphous alloys to developments in the 1980s-1990s of alloys like FINEMET, NANOPERM, and HITPERM. Recent developments discussed include core-shell nanoparticles, colloidal crystals, mesoporous nanocomposites, and functional polymers. Applications mentioned are using magnetic fields to destroy tumor cells, transformers, and DC-DC power converters. Challenges remaining are controlled synthesis, understanding mechanisms, cost, toxicity
Hebatalrahman nanotreatment
The document describes a laser indirect exposure method for treating nanomaterials. The method involves dipping powder materials in a transparent plastic to allow laser beams to pass through without being absorbed by the plastic. This indirectly exposes the powder to laser irradiation, which improves the mechanical properties of the materials. After exposure, an organic solvent is used to separate the treated nanomaterials from the dissolved plastic. Testing showed that laser treatment led to changes in Raman spectra and increased hardness of the treated materials. The method improves properties through laser energy absorption without causing economic losses or pollution.
Power Genertaion using Nanofiber
This document discusses using nanofibers to generate power from tires. Piezoelectric nanofibers like PZT-5A and PVDF could be embedded in tires to convert the mechanical energy from tire deformation into electrical energy. When stress is applied to these nanofibers due to tire movement or changes in pressure, a charge is produced through the piezoelectric effect. It is estimated these nanofibers could achieve a 25% energy conversion efficiency and generate several milliwatts of power. The document also notes that sensors may be needed to avoid resonance issues from the natural frequencies of the materials not matching tire frequencies.
Semiconductor Nanomaterials
This document discusses semiconductor nanomaterials and their applications in energy and the environment. It begins by defining semiconductors and discussing how their properties change at the nanoscale due to quantum effects. Common semiconductor materials include silicon, which is used in most electronics, as well as gallium arsenide and others. The document then covers topics such as doping to create n-type and p-type semiconductors, direct and indirect bandgaps, recombination processes, and quantum structures including quantum wells, wires and dots. Nanocrystals were first discovered in the 1980s and exhibit size-dependent optical properties due to quantum confinement effects.
B0460612
This document reports on the synthesis and characterization of copper indium disulfide (CuInS2) nanoparticles. CuInS2 nanoparticles were prepared by a solid state melt growth process under vacuum. X-ray diffraction analysis confirmed the formation of a chalcopyrite crystal structure in the as-prepared sample. Field emission scanning electron microscopy images showed an increase in nanoparticle size after annealing the sample at 200°C. Energy dispersive X-ray analysis demonstrated that the elemental composition of copper, indium, and sulfur was maintained close to the intended stoichiometric ratio.
EFFECT OF ULTRAVIOLET RADIATION ON STRUCTURAL PROPERTIES OF NANOWIRES
Copper nanowires were prepared through electrochemical template synthesis using Nucleopore polycarbonate membranes having nominal pore sizes of 800nm and 15nm diameter. The 800nm and 15nm nanowires thus grown were viewed under SEM and TEM respectively, while their FCC crystallographic structure was confirmed through X-ray and electron diffraction patterns. The X-ray diffraction peaks indicated strong texturing for (200). The texturing was found to reduce significantly upon exposure to ultraviolet radiation.
Electrospinning of nanofibers 2
The document discusses nanofibers and their production via electrospinning. It defines nanofibers as fibers with diameters less than 1000 nm and notes their small size compared to human hair. The document then explains the electrospinning process, where a high voltage draws thin fibers from a liquid source. Key aspects reviewed include the Taylor cone formation, bending instability that reduces fiber diameters, and parameters that impact electrospinning. Finally, it outlines early nanofiber production at UPLB involving various polymers like PCL, PVC and PLGA.
IRJET- The Ab Initio Study of Electronic and Optical Properties of CH3NH3ZnI3...
This document summarizes an ab initio study of the electronic and optical properties of the perovskite solar cell material CH3NH3ZnI3. Key findings include:
1) CH3NH3ZnI3 has a direct bandgap of 0.34 eV, which is significantly smaller than the 1.53 eV bandgap of the commonly used CH3NH3PbI3 material.
2) X-ray diffraction data analysis showed that CH3NH3ZnI3 retains the original cuboctahedral crystal structure of CH3NH3PbI3.
3) Optical property calculations predicted CH3NH3ZnI3 would absorb electromagnetic radiation in the far UV region and
Dielectric properties of Ni-Al nano ferrites synthesized by citrate gel method
Ni–Al ferrite with composition of NiAlxFe2-xO4 (x=0.2, 0.4 0.6, and 0.8, ) were prepared by citrate gel method. The Dielectric Properties for all the samples were investigated at room temperature as a function of frequency. The Dielectric constant shows dispersion in the lower frequency region and remains almost constant at higher frequencies. The frequency dependence of dielectric loss tangent (tanδ) is found to be abnormal, giving a peak at certain frequency for mixed Ni-Al ferrites. A qualitative explanation is given for the composition and frequency dependence of the dielectric loss tangent.
Study of doped chromiun oxide nanoparticle
This document outlines a study on the synthesis and characterization of doped Cr2O3 nanoparticles. It will investigate doping Cr2O3 nanoparticles with elements like Fe, ZnO, and Co using microwave synthesis and sol-gel methods. Characterization of the structural, electrical, and optical properties of the doped nanoparticles will be conducted using techniques like XRD, SEM, and FTIR. The study aims to better understand how doping affects the properties of Cr2O3 nanoparticles compared to the bulk material. A timeline is provided outlining the literature review, experimental work, characterization, drafting and final submission over a 5 month period.
Jean ISDRS 2007
1. The document discusses metal-molecule-GaAs devices using self-assembled monolayers of redox-active molecules.
2. Three molecules - octadecanethiol, a ligand, and a ruthenium complex - were deposited on GaAs and tested.
3. Current-voltage measurements showed higher current densities in the molecular devices compared to a control metal-semiconductor device, and thermionic and thermionic-field emission models were found to fit the data.
Graphene ppt
The document discusses graphene, a one-atom thick sheet of carbon atoms arranged in a honeycomb lattice. Graphene was discovered in 2003 when researchers found thin flakes of it on scotch tape. It has remarkable mechanical, thermal, electrical, and optical properties such as being very strong yet flexible, highly conductive, and nearly transparent. These properties give graphene potential applications in areas like integrated circuits, water purification, gas sensors, transistors, solar cells, and flexible displays. However, widespread use of graphene is limited by challenges in production costs, quality control, and the lack of a bandgap.
Synthesis & Heating Mechanisms of Magnetic Nanoparticles in Hyperthermia Trea...
This document summarizes research on synthesizing magnetic nanoparticles for use in hyperthermia cancer treatment. It discusses two samples of magnesium ferrite nanoparticles synthesized via co-precipitation at different temperatures and concentrations. Characterization with XRD and VSM showed the samples had hexagonal structure and increasing magnetization with higher sintering temperature. In hyperthermia experiments, both samples saw increased temperature over time with applied alternating magnetic fields, with better results at higher frequencies above 500 kHz needed to effectively treat cancer.
Fabrication and electrical characteristic of quaternary ultrathin hf tiero th...
This document describes the fabrication and electrical characterization of quaternary ultrathin HfTiErO thin films grown by RF sputtering for MOS devices. HfTiErO thin films with different Ti and Er contents were deposited on silicon substrates. The films were annealed at 500°C and 700°C. Atomic force microscopy showed the surface roughness decreased with annealing. X-ray photoelectron spectroscopy analysis showed the chemical compositions. MOS capacitors were fabricated and capacitance-voltage measurements showed the annealed films at 500°C had improved electrical properties like higher dielectric constant. The HfTiErO film with composition HfTi6Er4O annealed at 500°C achieved the best electrical performance of the
What's hot (18)
Research issues in graphene field effect transistor
Research issues in graphene field effect transistor
EFFECT OF ULTRAVIOLET RADIATION ON STRUCTURAL PROPERTIES OF NANOWIRES
EFFECT OF ULTRAVIOLET RADIATION ON STRUCTURAL PROPERTIES OF NANOWIRES
IRJET- The Ab Initio Study of Electronic and Optical Properties of CH3NH3ZnI3...
IRJET- The Ab Initio Study of Electronic and Optical Properties of CH3NH3ZnI3...
Dielectric properties of Ni-Al nano ferrites synthesized by citrate gel method
Dielectric properties of Ni-Al nano ferrites synthesized by citrate gel method
Synthesis & Heating Mechanisms of Magnetic Nanoparticles in Hyperthermia Trea...
Synthesis & Heating Mechanisms of Magnetic Nanoparticles in Hyperthermia Trea...
Fabrication and electrical characteristic of quaternary ultrathin hf tiero th...
Fabrication and electrical characteristic of quaternary ultrathin hf tiero th...
Viewers also liked
Global-13
The document summarizes research on modeling the temperature dependence of the inverse dielectric susceptibility in KDP-type crystals. The authors used a four-particle cluster model Hamiltonian with third- and fourth-order phonon anharmonic interaction terms. They derived expressions for the renormalized soft mode frequency and inverse dielectric susceptibility using the double-time temperature dependent Green's function method. By fitting model parameters, they evaluated the temperature dependence of the soft mode frequency and inverse dielectric susceptibility for KDP crystals in the paraelectric phase. Their theoretical results agreed well with experimental data from other studies.
Vortex Polarization Instabilities in PbTiO3 Nanowires
This document discusses polarization instabilities in PbTiO3 nanowires based on density functional theory computations. The key findings are:
1) Vortex or non-rectilinear polarization states are found to be the equilibrium polarization configuration in TiO2-terminated PbTiO3 nanowires above a critical size of 1.6 nm.
2) Four possible switchable polarization states are identified for PbTiO3 nanowires: clockwise/counter-clockwise vortex and positive/negative axial polarization.
3) The instability towards vortex polarization is associated with imaginary zone-center phonon eigenvectors, analogous to a soft optical phonon mode driving the ferroelectric transition in the bulk.
Polarization, strain induced phase transitions and dielectric response in ult...
Ultrathin PbTiO3 nanowires can have switchable straight or vortex polarization configurations depending on their termination and strain. PbO termination and tensile strain favor straight polarization while TiO2 termination and compressive strain favor vortex polarization. The static and optical dielectric permittivity is significantly enhanced along the axial direction but reduced in other directions due to depolarizing fields. Nanowires with vortex polarization are expected to have particularly large dielectric permittivity.
Electric properties
Simple description with polarisation curves and applications of dielectrics, paraelectrics and ferroelectrics.
The End of Growth- Preparing for a new normal
The document discusses how economic growth as currently defined cannot continue indefinitely due to finite resources and environmental limits. It outlines how factors both within and external to the financial system, such as declining EROI for energy sources, peak oil, and resource depletion, signal the end of economic growth as we have known it. The text advocates for reforming economic theories away from a growth-based model to an ecological economics framework that incorporates environmental impacts. It also presents strategies for communities to pursue such as transition initiatives, local currencies, and developing resilience and sustainability.
Materials and their properties presentation
This document discusses materials and their properties. It defines materials as physical substances used to make things and lists some main categories including metals, plastics, ceramics, glass and fibers. It then discusses properties of materials as descriptions of their characteristics like hardness, strength, flexibility. Examples are given of materials around us and properties are listed. Metals are highlighted as one main group of materials that are shiny, strong, good conductors and usually opaque, with examples like aluminum and copper.
The 2015 Millennial Majority Workforce: Study Results
Millennials will be the largest generation in the U.S. workforce as of 2015. Yet businesses have a difficult time hiring members of this youngest professional generation. Disjoints abound as the nation’s workforce shifts -- millions of jobs remain unfilled while many millennials struggle to build careers. This study reveals changes in how we work, generational differences, and the critical role millennials play for businesses as we move forward.
Viewers also liked (7)
Vortex Polarization Instabilities in PbTiO3 Nanowires
Vortex Polarization Instabilities in PbTiO3 Nanowires
Polarization, strain induced phase transitions and dielectric response in ult...
Polarization, strain induced phase transitions and dielectric response in ult...
The 2015 Millennial Majority Workforce: Study Results
The 2015 Millennial Majority Workforce: Study Results
Similar to cBodanov emrs2012
Study of Structural and Dielectric properties of BaTiO3 Doped with Mg-Cu-Zn F...
The magnetoelectric (ME) composites having the general formula, (x) Mg0.25Cu0.25Zn0.5Fe2O4 + (1-x) BaTiO3 (x=15%, 30%, 45%) were synthesized by sintering mixtures of highly ferroelectric BaTiO3 and highly magnetostrictive magnetic component Mg0.25Cu0.25Zn0.5Fe2O4. The presence of constituent phases of ferrite, ferroelectric and their composites were confirmed by X-ray diffraction (XRD) studies. Surface morphology of the samples has been investigated using Field Emission Scanning Electron Microscope (FESEM), which revealed uniform mixing of two phases. The variations in dielectric constant and dissipation factor as a function of frequency from 100 Hz to 1 MHz were measured in a Hioki LCR Hi-Tester. The dielectric constant and dielectric loss were found to decrease rapidly in the low frequency region and became almost constant in the high frequency region. The electrical conductivity deduced from the measured dielectric parameters has been analyzed and found that the conduction mechanism in these composites is in conformity with small polaron hopping model.
Electronic structure of strongly correlated materials Part III V.Anisimov
This document discusses results from DFT+DMFT calculations on various strongly correlated materials. It summarizes calculations showing a strongly correlated metal state in SrVO3 with a lower Hubbard band, a Mott insulator transition in V2O3 accompanied by a small structural change, and heavy fermion behavior in Li2VO4 without f-electrons. It also discusses calculations of the charge transfer insulator NiO, pressure-induced transitions in MnO and Fe2O3, correlated covalent insulators FeSi and FeSb2, superconductivity in LaOFeAs, Jahn-Teller distortions and orbital ordering in KCuF3, and f-electron localization in cerium. The document
1 s2.0-s0022369702003566-main
This document summarizes an experimental study comparing electron momentum spectroscopy (EMS) measurements of the electronic band structures of beryllium (Be) and beryllium oxide (BeO) to tight-binding calculations. EMS directly measures band dispersions and intensities with high resolution. Be and BeO provide benchmark systems due to their low atomic number and ability to form thin films, reducing multiple scattering. EMS data is compared to calculations using density functional theory (DFT) with reasonable agreement found. Some discrepancies remain, such as DFT underestimating the bandgap and bandwidths of BeO.
Burakh 040816
Himmetoglu presents research on modeling polarons and their effects in complex oxide materials like YTiO3 using first-principles calculations. Small polarons form when holes become self-trapped due to strong electron-phonon coupling, leading to localized distortions around the hole. Calculations find two stable configurations for a single hole - a small polaron state and a delocalized hole state. The transition between these states is attributed to the 0.6eV onset seen in optical absorption measurements, rather than representing the fundamental band gap. Accounting for small polaron formation reconciles theoretical predictions of band gaps around 2eV with experimental observations.
Structural and magnetic properties on F-doped LiVO2 with two-dimensional tria...
The layered oxide LiVO2 recently has received more attention due to its interesting structural and magnetic behaviors involving the two-dimensional magnetic frustration in these systems. We synthesized a series of F-doped LiVO2 samples, and reported the F-doping effect on the structure and transition temperature Tt. The samples LiVO2-xFx (x=0, 0.1, 0.2 and 0.3) were characterized by X-ray diffraction, scanning electron microscope (SEM), differential scanning calorimetry (DSC), magnetic susceptibility and specific heat measurement. The structural analysis shows that with increasing x, the ratio of lattice parameter c/a increasing, i.e. in the a-b plane the lattice is compressed while in the c-axis direction the lattice expands. The DSC measurements show that a first-order phase transition happens at around 500 K, and the thermal hysteresis around phase transition temperature Tt increases with increasing x. Substitution of O with F ions results in a change of two dimensional characteristics and the distortion of the VO6 block in structure, which significantly influence the magnetic ordering transition temperature Tt.
Development of highly accurate pseudopotential method and its application to ...
The document describes the development of a highly accurate pseudopotential method and its application to calculations of silicene grown on a ZrB2 surface. Key points:
1. A novel pseudopotential method called MBK is developed that can replicate scattering characteristics over a broad energy range, improving upon existing pseudopotentials.
2. Calculations show buckled silicene can stably grow on a ZrB2 surface with strong interaction between the silicene and ZrB2.
3. Band structure calculations match well with experimental data and show orbital splitting from the Dirac cone in silicene due to interactions with the ZrB2 surface.
Presentation on Properties investigation of perovskite
Pressure-dependent physical properties of cubic SrBO3 (B = Cr, Fe) perovskites investigated by density functional theory (DFT)
Laksman2014-Cysteine
This study examines dissociation pathways in the dication of the amino acid cysteine after site-selective core ionization of the O 1s, N 1s, C 1s, and S 2p orbitals. A photoelectron-ion-ion coincidence experiment was performed. Several dissociation channels were identified, some showing strong site-selective dependence attributed to a combination of nuclear motion in the core-ionized state and Auger processes populating different electronic states in the dication. Fragmentation patterns were analyzed at each core ionization level to determine dissociation pathways and kinetic energy release partitioning between fragments through regression slope analysis.
Ferro2016
The document summarizes research on the electrocaloric effect in ferroelectric nanowires compared to bulk materials. Key findings include:
1) The maximum electrocaloric response is reduced in nanowires compared to bulk, due to decreased spontaneous polarization and dielectric constant from reduced correlation length.
2) In polydomain nanowires, both the BaTiO3 and KNbO3 nanowires lose their electrocaloric properties, as the electric field is not well aligned with polarization in each domain.
3) The largest electrocaloric response occurs near phase transition temperatures where crystal structure changes and entropy is maximized, as shown in simulations of the electrocaloric temperature change.
Reflectance and photoluminescence characterization of BexZn1
This document summarizes research on the optical properties of BexZn1-xTe thin films grown by molecular beam epitaxy. Reflectance and photoluminescence measurements were performed on the epilayers as a function of BeTe content and temperature. An increase in emission line broadening was observed with higher BeTe content, which is attributed to alloy disorder. Temperature-dependent reflectance data showed a reduction in the variation of band gap energy with increasing BeTe content. This effect is proposed to be due to lattice hardening from BeTe decreasing the lattice contribution to the temperature dependence.
Atomic data and spectral models for lowly ionized iron-peak species
This document discusses the need for reliable atomic data and spectral models for lowly ionized iron-peak species like Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu. Current models are inaccurate, with predicted line intensities disagreeing with observations by factors of several. The goals of the project are to compute new atomic data, construct improved spectral and opacity models, and implement the models in photoionization codes. The document outlines challenges in modeling these ions and describes ongoing work using relativistic R-matrix methods to calculate improved collision strengths and photoionization cross sections.
Effect of calcination on the electrical properties and quantum confinement of...
Effect of calcination on the electrical properties and quantum confinement of...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and TechnologyEffect of calcination on the electrical properties and quantum confinement of...
Abstract Fe2O3 nanoparticles have been prepared by a simple solvothermal method using a domestic microwave oven. X-ray powder diffraction measurement indicates the amorphous nature of the as-prepared sample. Calcined samples were obtained by annealing the as-prepared sample at different temperatures, viz. 400, 500, 600 and 700oC. Transmission electron microscopic images indicate that all the five samples are spherical in shape. AC electrical measurements were carried out on pelletized samples by the parallel plate capacitor method at various temperatures ranging from 40-130oC and frequencies ranging from 100 Hz -1 MHz. Results indicate low AC electrical conductivities and consequently show the occurrence of nano confined states. The exciton Bohr radii obtained from the dielectric constant values at 40oC temperature and 1 kHz frequency are 41.8, 54.8, 55.3, 56.3 and 27.0 respectively for the as-prepared sample and samples calcined at 400, 500, 600 and 700oC which indicate a strong quantum confinement effect. The impedance spectra observed exhibit non-ideal behavior. Keywords: Semiconductors, Magnetic materials, Nanoparticles, Electrical properties
Energy band structure and electrical conductivity mechanisms of metals and se...
Solid-state physics; energy band structure; electrical conductivity; semiconductors; extrinsic semiconductors; intrinsic semiconductors; in-depth analysis.
Capitalizing multiferroic properties of BiFeO3 for spintronics
This document summarizes research on the multiferroic material bismuth ferrite (BiFeO3). Key points:
- BiFeO3 was successfully synthesized using an auto-combustion technique and characterized using various methods.
- X-ray diffraction confirmed the material has a rhombohedral perovskite crystal structure. Magnetic measurements showed antiferromagnetic behavior.
- Dielectric measurements found an anomaly near the Neel temperature, indicating magnetoelectric coupling between the electric and magnetic orders.
- The material showed potential for applications in spintronics due to exhibiting both ferroelectricity and antiferromagnetism at room temperature.
Synopsis : Bismuth Sodium Titanate ( A lead free Ferroelectric Material
Synopsis : Bismuth Sodium Titanate ( A lead free Ferroelectric MaterialNational Tsing Hua University
This document summarizes a thesis submitted for a Master's degree in nano-optoelectronics. The thesis focuses on synthesizing and characterizing bismuth sodium titanate (BNT), a lead-free ferroelectric material. BNT is studied as an alternative to lead zirconate titanate (PZT), which is widely used but toxic. The thesis will synthesize BNT using solid-state and sol-gel methods, characterize its structure and properties, and compare the results. Characterization tools like XRD, SEM, and dielectric measurements will be used. If successful, BNT could replace PZT in applications like sensors and actuators while avoiding lead's toxicity issues.Bg31399402
This document compares the optical properties of PZT(65/35) and PLZT(96/4/65/35) ceramics in the rhombohedral phase using density functional theory calculations. The key findings are:
1) PLZT has a higher density of states above the Fermi level compared to PZT due to the presence of localized La-4f states.
2) PLZT has more plasma oscillation roots in its dielectric function spectrum compared to PZT, indicating stronger plasma oscillations.
3) The refractive index and birefringence of PLZT are higher than PZT, showing PLZT has better optical properties for applications like lasers.
Presentation@HITMS
This document summarizes a PhD candidate's research on using first principles calculations to study the electronic and magnetic properties of iron, chromium, and their binary alloys FeCr and FeCr3. The candidate uses the TB-LMTO-ASA method to calculate properties like minimum energy, density of states, band structure, and charge density. Results show the elemental metals have 9 bands along symmetry axes, while the alloys have 18 and 36 bands respectively. Contributions to magnetic moments from s and p orbitals are small, with d-orbitals being the major contributor near the Fermi level. The research provides insights into these materials' electronic structures at an atomic scale.
Study of highly broadening Photonic band gaps extension in one-dimensional Me...
This document discusses the theoretical study of enhancing the reflectance spectra of one-dimensional metallo-organic multilayer photonic structures. It examines structures composed of alternating thin layers of silver and the organic material N,N'-bis-(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine. The transfer matrix method is used to calculate the reflectance spectra for different configurations of layer thicknesses and incident angles of light. Tuning of the photonic band gap is observed by varying the thickness of either the metal or organic layers. Broadening and shifting of the band edges from ultraviolet to visible and infrared regions occurs due to the optical absorption properties of both the
cry
Crystal field theory was proposed in the 1950s to describe the bonding in ionic crystals and metal complexes. It uses an electrostatic model to explain how ligands interact with the d-orbitals of a central metal ion. This interaction splits the degeneracy of the d-orbitals into lower-energy orbitals (t2g) and higher-energy orbitals (eg). The crystal field splitting energy is determined by factors like the ligand type, metal oxidation state, and complex geometry. Crystal field theory can be used to determine properties of complexes such as color, magnetism, and spinel structures. It provides explanations for phenomena like Jahn-Teller distortions but has limitations and cannot fully describe covalent bonding.
Similar to cBodanov emrs2012 (20)
Study of Structural and Dielectric properties of BaTiO3 Doped with Mg-Cu-Zn F...
Study of Structural and Dielectric properties of BaTiO3 Doped with Mg-Cu-Zn F...
Electronic structure of strongly correlated materials Part III V.Anisimov
Electronic structure of strongly correlated materials Part III V.Anisimov
Structural and magnetic properties on F-doped LiVO2 with two-dimensional tria...
Structural and magnetic properties on F-doped LiVO2 with two-dimensional tria...
Development of highly accurate pseudopotential method and its application to ...
Development of highly accurate pseudopotential method and its application to ...
Presentation on Properties investigation of perovskite
Presentation on Properties investigation of perovskite
Reflectance and photoluminescence characterization of BexZn1
Reflectance and photoluminescence characterization of BexZn1
Atomic data and spectral models for lowly ionized iron-peak species
Atomic data and spectral models for lowly ionized iron-peak species
Effect of calcination on the electrical properties and quantum confinement of...
Effect of calcination on the electrical properties and quantum confinement of...
Effect of calcination on the electrical properties and quantum confinement of...
Effect of calcination on the electrical properties and quantum confinement of...
Energy band structure and electrical conductivity mechanisms of metals and se...
Energy band structure and electrical conductivity mechanisms of metals and se...
Capitalizing multiferroic properties of BiFeO3 for spintronics
Capitalizing multiferroic properties of BiFeO3 for spintronics
Synopsis : Bismuth Sodium Titanate ( A lead free Ferroelectric Material
Synopsis : Bismuth Sodium Titanate ( A lead free Ferroelectric Material
Study of highly broadening Photonic band gaps extension in one-dimensional Me...
Study of highly broadening Photonic band gaps extension in one-dimensional Me...
More from bpnv38
Phys rev.186.276 alig
The absorption spectrum of cerium-doped calcium fluoride (CaF2:Ce2+) was observed at several temperatures. At low temperatures, the spectrum consists of transitions from the ground state to levels of the 4f configuration. A crystal field calculation shows that in CaF2's strong crystal field, the ground state of Ce2+ is a T2 level of the 4f5d configuration rather than the 4f configuration of the free ion. Measurements of the Zeeman effect confirm the T2 character of the ground state. The calculated energies and intensities of transitions from the ground state to 4f levels agree well with the observed optical absorption spectrum, especially in the near-infrared region.
Mysovsky rpc2006
Theoretical modelling of photoconversion and aggregation of oxygen centres in calcium fluoride
1) Theoretical calculations using B3LYP functional and large quantum clusters provide quantitative agreement with experimental hyperfine couplings for F centers within 15% error and predict optical transition energies for F centers and oxygen-vacancy dipoles within 0.1 eV of experiment.
2) Calculations show O- ions should have an optical absorption band around 7 eV, though this has not been observed experimentally.
3) Possible recombination channels are discussed for oxygen-vacancy dipoles that were photodissociated, including tunnelling processes and migration/separation of defects.
Popov eurodim2014
This document summarizes a first-principles study of the electronic structure of Ce3+ centers in alkaline-earth fluorides including spin-orbit and scalar relativistic effects. The study used an embedded quantum cluster approach to model Ce3+ centers in CaF2 and SrF2 with and without interstitial fluorine ions. Calculations of 4f-5d optical transitions using CASPT2 and including spin-orbit coupling showed good agreement with experimental absorption spectra. Jahn-Teller relaxation was found to induce asymmetry in cubic Ce3+ centers, improving the match to measured spectra. The developed approach allows sophisticated quantum chemistry methods to be applied to defect systems in solids.
Mysovsky scint2009
This study examines new excitonic luminescence bands in CaF2 and SrF2 crystals using ab initio calculations. Calculations show self-trapping of electrons is possible and energetically favorable in these crystals, forming a trigonal symmetric defect with hyperfine properties distinct from known defects. Self-trapped electrons may be precursors to an unknown excitonic configuration responsible for the new higher-energy luminescence bands observed, which do not depend on impurity concentration unlike main bands. On-center self-trapped excitons were also calculated but found to be unstable and not match the energy of the new bands.
Ieee m-2012
This summary provides the key details from the document in 3 sentences:
This article discusses ab initio calculations of absorption spectra for alkaline earth fluoride crystals doped with cerium or praseodymium ions. The calculations examine cubic and tetragonal defect centers and determine crystal field splitting of energy levels. The results are consistent with experimental data and identify that band C in the absorption spectra corresponds to transitions of rare earth ions in tetragonal centers.
More from bpnv38 (6)
Recently uploaded
ANAMOLOUS SECONDARY GROWTH IN DICOT ROOTS.pptx
Abnormal or anomalous secondary growth in plants. It defines secondary growth as an increase in plant girth due to vascular cambium or cork cambium. Anomalous secondary growth does not follow the normal pattern of a single vascular cambium producing xylem internally and phloem externally.
Sharlene Leurig - Enabling Onsite Water Use with Net Zero Water
Sharlene Leurig - Enabling Onsite Water Use with Net Zero WaterTexas Alliance of Groundwater Districts
Presented at June 6-7 Texas Alliance of Groundwater Districts Business MeetingApplied Science: Thermodynamics, Laws & Methodology.pdf
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
BREEDING METHODS FOR DISEASE RESISTANCE.pptx
Plant breeding for disease resistance is a strategy to reduce crop losses caused by disease. Plants have an innate immune system that allows them to recognize pathogens and provide resistance. However, breeding for long-lasting resistance often involves combining multiple resistance genes
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/Shallowest Oil Discovery of Turkiye.pptx
The Petroleum System of the Çukurova Field - the Shallowest Oil Discovery of Türkiye, Adana
3D Hybrid PIC simulation of the plasma expansion (ISSS-14)
3D Particle-In-Cell (PIC) algorithm,
Plasma expansion in the dipole magnetic field.
ESR spectroscopy in liquid food and beverages.pptx
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
Cytokines and their role in immune regulation.pptx
This presentation covers the content and information on "Cytokines " and their role in immune regulation .
Phenomics assisted breeding in crop improvement
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...
Travis Hills of Minnesota developed a method to convert waste into high-value dry fertilizer, significantly enriching soil quality. By providing farmers with a valuable resource derived from waste, Travis Hills helps enhance farm profitability while promoting environmental stewardship. Travis Hills' sustainable practices lead to cost savings and increased revenue for farmers by improving resource efficiency and reducing waste.
Equivariant neural networks and representation theory
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
bordetella pertussis.................................ppt
Bordettela is a gram negative cocobacilli spread by air born drop let
8.Isolation of pure cultures and preservation of cultures.pdf
Isolation of pure culture, its various method.
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
Recently uploaded (20)
Sharlene Leurig - Enabling Onsite Water Use with Net Zero Water
Sharlene Leurig - Enabling Onsite Water Use with Net Zero Water
Applied Science: Thermodynamics, Laws & Methodology.pdf
Applied Science: Thermodynamics, Laws & Methodology.pdf
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...
3D Hybrid PIC simulation of the plasma expansion (ISSS-14)
3D Hybrid PIC simulation of the plasma expansion (ISSS-14)
ESR spectroscopy in liquid food and beverages.pptx
ESR spectroscopy in liquid food and beverages.pptx
Cytokines and their role in immune regulation.pptx
Cytokines and their role in immune regulation.pptx
mô tả các thí nghiệm về đánh giá tác động dòng khí hóa sau đốt
mô tả các thí nghiệm về đánh giá tác động dòng khí hóa sau đốt
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...
Equivariant neural networks and representation theory
Equivariant neural networks and representation theory
bordetella pertussis.................................ppt
bordetella pertussis.................................ppt
8.Isolation of pure cultures and preservation of cultures.pdf
8.Isolation of pure cultures and preservation of cultures.pdf
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...
cBodanov emrs2012
- 1. The effect of mutual arrangement of B- cations on electronic, optical and piezoelectric properties of strained PbZrxTi1-xO3 (PZT) Alexander Bogdanov1,2, Anna Kimmel3,4 1. A.P. Vinogradov Institute of Geochemistry SB RAS, Irkutsk, RUSSIA 2. Irkutsk State Technical University, Irkutsk, RUSSIA 3. National Physical Laboratory, Teddington, TW11 0LW, UK 4. University College London, Gower St., WC1E 6BT, UK
- 2. INTRODUCTION PZT is solid solution perovskite A(BB’)O3. The material demonstrates excellent piezoelectric properties and is widely used in ferro- and piezo- applications. Macroscopic phase and macroscopic properties of PZT depend on the ratio of B- cations (i.e. x) and their mutual arrangement. In this work we study the correlation of local arrangement of B-cations with macroscopic phase, piezoelectric and optical properties of PZT
- 3. METHODS We conduct calculations of non-defect PbZrxTi1-xO3 phases at x=0.5 with different mutual arrangements of Zr and Ti cations. B-cation disorder: specific placing of Zr and Ti in B-cation sites of 40-atoms PZT cell. Methods: DFT, GGA with PBE and Wu-Cohen functionals. Optical, Ferro- and Piezoelectric properties: Linear Response theory and Density Functional Perturbation Theory. Simulation of Strain: relaxation of c-axis with constrained a and b axes. 21 43 5
- 4. STRUCTURAL PARAMETERS 21 43 5 Lattice tetra tetra triclin tetra rhomb Group P4mm P4mm Cm Cm P1 a, Å 3.99 3.98 4.10 3.99 4.04 c, Å 4.20 4.26 4.00 4.22 4.04 |P|, C/m2 0.60 0.82 0.70 0.70 0.55 Energy, eV +0.07 +0.00 +0.04 +0.05 +0.02 Lattice tetra tetra tetra cubic tricl Group P4/mmm P4/mmm C2/m C2/m P-1 a, Å 4.05 4.01 4.04 4.03 4.03 c, Å 4.01 4.05 4.01 4.03 3.99 Energy, eV +0.23 +0.20 +0.19 +0.21 +0.05 FERROELECTRIC STATES PARAELECTRIC STATES
- 5. OPTICAL AND ELECTRONIC STRUCTURE PROPERTIES We have found a strong intermixing of Zr and Ti d-states in our structures which can give optical applications while PZT is doped by non-isovalent cations Optical band gap Eg~3.5 eV (from optical spectra) does not show significant dependence on Zr/Ti arrangement, in agreement with experimental results for thin films[*] * M.P. Moret, M.A.C. Devillers, K. Wörhoff, P.K. Larsen, Journal of Applied Physics 92, 468 (2002). Top of VB: oxygen 2p-states Bottom of CB: Ti, Zr d-states HOMO, #5 (FE) LUMO, #5 (FE)
- 6. 1 2 3 4 5 PIEZOELECTRIC PROPERTIES e15 10.65 3.66 0.37 7.46 0.49 e31 0.27 0.37 -2.00 0.37 -0.35 e33 4.11 3.94 7.07 4.17 8.45 ε11 488.23 126.56 56.87 375.40 79.59 ε33 13.77 13.94 136.53 14.47 79.93 |P| 0.60 0.82 0.70 0.70 0.55 Pdirection [001] [001] [552] [001] [111] tetra tetra triclin tetra rhomb Piezoelectric coefficients, C/m2 Static dielectric permittivity Spontaneous polarization, C/m2 Exp: e33=11.9 Cm2 Low temperature, pylycrystal Zr/Ti 50:50 * Exp: |P|=0.75 Cm2 single domain crystal ** * Z. Q. Zhuang, M. J. Haun, S. J. Jang, and L. E. Cross, 6th IEEE International Symposium on the Applications of Ferroelectrics, 1986, p. 394. 21 43 5
- 7. ORIGIN OF PIEZOELECTRIC RESPONSE e15 High polarization at xy plane occurs due to Ti plane is less stressed than Zr one. This is due to Zr/Ti size ratio and Ti “free volume” at applied σ5 shear strain. 1 Shear strain σ5 P e15=10.65 Cm2 Main factor – freedom to move Ti in xy plane 4 e15=7.46 Cm2
- 8. 5/27/2014 ORIGIN OF PIEZOELECTRIC RESPONSE e33 B O d Force Force OO No. dZr-O, Å dTi-O, Å e33, Cm2 1 1.97 1.77 4.11 2 1.98 1.75 3.94 3 2.04 1.91 7.07 4 1.95 1.79 4.17 5 2.02 1.89 8.45 Highest responses correspond to shortest distances between B-cation and overlying oxygen atom. Under mechanical stress B-cation shifts from the centre of octahedra the more the less it was shifted initially. Main factor – distance between B-cation and overlying oxygen atom (along z-axis)s
- 9. Response to strain of Ps and eij of tetragonal structures #2 and #4
- 10. Summary • We studied systematically electronic, optical, piezoelectric response of PZT to local ordering of B-cations. Tetragonal structure #2 (P4mm) was found to be most stable among found phases, characterized by highest polarization. We also found isoenergetic polar #4 (Cm) and non-polar #5 (P-1) phases. • Analysis of electronic properties demonstrate dependence of electronic structure on B-cations mutual arrangement, we found strong intermixing of Ti and Zr d-states for #5. • We found that structure #1, #4 give large e15 coefficients, which is due to plane- to-plane arrangement of B-cations. • The large e33 piezo-coefficient in #3, #5 is due to the small shift of B-cations from centre of oxygen octahedra along c-axis (low P along c). • The analysis of polarization and piezo-coefficients with respect to strain showed that the gradients of piezo-coefficients strong depend on the B-cations mutual arrangement.
- 11. 5/27/2014 Acknowledgements We are thankful to Markus Gain (National Physical Laboratory) and Andrew Mysovsky (Irkutsk State Technical University) for important advices and quite useful discussions. The calculations were performed by HPC facilities of Legion (UK), Fock (Irkutsk, RUSSIA).