Pub Date : 2016-12-31DOI: 10.1080/23311940.2016.1262725
N. Korneev
A perturbation theory for weakly distorted regular cavity which has classical ray trajectories lying on invariant tori, is constructed to a higher perturbation order, than for the general case. This is possible because of a special structure of semi-classical eigenvalues for integrable Hamiltonians. The perturbation magnitude here has an order of a characteristic wavelength of a mode instead of usual wavelength square. The results are expressed in solutions of the Hill equation. The set includes modes localized along stable periodic ray trajectories; scar modes, corresponding to unstable periodic trajectories; weakly distorted modes of regular cavity, and intermediate cases. The application of the method to square, circular and elliptical cavities is outlined.
{"title":"Perturbation approximation for higher modes in nearly regular two-dimensional cavities","authors":"N. Korneev","doi":"10.1080/23311940.2016.1262725","DOIUrl":"https://doi.org/10.1080/23311940.2016.1262725","url":null,"abstract":"A perturbation theory for weakly distorted regular cavity which has classical ray trajectories lying on invariant tori, is constructed to a higher perturbation order, than for the general case. This is possible because of a special structure of semi-classical eigenvalues for integrable Hamiltonians. The perturbation magnitude here has an order of a characteristic wavelength of a mode instead of usual wavelength square. The results are expressed in solutions of the Hill equation. The set includes modes localized along stable periodic ray trajectories; scar modes, corresponding to unstable periodic trajectories; weakly distorted modes of regular cavity, and intermediate cases. The application of the method to square, circular and elliptical cavities is outlined.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2016.1262725","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60084777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-12-31DOI: 10.1080/23311940.2016.1240886
H. Bulut, S. S. Atas, H. Baskonus
Abstract In this manuscript, we consider the Bernoulli sub-equation function method for obtaining new exponential prototype structures to the Cahn–Allen mathematical model. We obtained new results using this technique. We plotted two- and three-dimensional surfaces of the results using Wolfram Mathematica 9. At the end of this manuscript, we submitted a conclusion in a comprehensive manner.
{"title":"Some novel exponential function structures to the Cahn–Allen equation","authors":"H. Bulut, S. S. Atas, H. Baskonus","doi":"10.1080/23311940.2016.1240886","DOIUrl":"https://doi.org/10.1080/23311940.2016.1240886","url":null,"abstract":"Abstract In this manuscript, we consider the Bernoulli sub-equation function method for obtaining new exponential prototype structures to the Cahn–Allen mathematical model. We obtained new results using this technique. We plotted two- and three-dimensional surfaces of the results using Wolfram Mathematica 9. At the end of this manuscript, we submitted a conclusion in a comprehensive manner.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2016.1240886","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60085152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-12-31DOI: 10.1080/23311940.2016.1236510
P. Dawar, N. S. Raghava, A. De
Abstract In this paper, design and analysis of U–T-shaped metamaterial antenna have been presented. It shows negative permittivity and permeability characteristics. The metamaterial array is embedded inside the substrate of rectangular microstrip patch antenna. Upon incorporation, directivity increases by 24% and gain increases by 18%. Results were compared with equivalent circuit analysis of patch antenna and are well in coherence with FEM (finite-element method)-based Ansoft HFSS (high-frequency structure simulator) simulation with around 1% error. Using fractal metamaterial antenna of first and second order iterative mathematics, antenna is miniaturized by 58 and 75% along with improvement in bandwidth.
{"title":"High gain, directive and miniaturized metamaterial C-band antenna","authors":"P. Dawar, N. S. Raghava, A. De","doi":"10.1080/23311940.2016.1236510","DOIUrl":"https://doi.org/10.1080/23311940.2016.1236510","url":null,"abstract":"Abstract In this paper, design and analysis of U–T-shaped metamaterial antenna have been presented. It shows negative permittivity and permeability characteristics. The metamaterial array is embedded inside the substrate of rectangular microstrip patch antenna. Upon incorporation, directivity increases by 24% and gain increases by 18%. Results were compared with equivalent circuit analysis of patch antenna and are well in coherence with FEM (finite-element method)-based Ansoft HFSS (high-frequency structure simulator) simulation with around 1% error. Using fractal metamaterial antenna of first and second order iterative mathematics, antenna is miniaturized by 58 and 75% along with improvement in bandwidth.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2016.1236510","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60085144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-12-31DOI: 10.1080/23311940.2016.1254859
Y. Hafez, E. Awad
Abstract Radon migration from deep soil to the earth’s surface is investigated numerically using a developed Finite Element numerical model. The objectives of this study are: to predict the radon profile variation with the soil depth, the radon diffusion coefficients in multi-layer soils, the surface radon concentrations, and the soil–air radon fluxes. The flexibility of the Finite Element Method allows for accommodating varying diffusion coefficients in multi-layer soils and expressing convective-type boundary conditions. The convective-type boundary condition assumes that the surface radon flux is proportional to the difference between the radon concentration in the ambient air and the radon concentration at the soil surface. Radon concentration profiles with depth were collected from several geophysical locations such as Greece, Germany, South Africa, and Jordan. The numerical results show that the multi-layer profile of radon in natural soils is more descriptive than the one-layer one used traditionally, where each layer has its own diffusion coefficient. The effective diffusion coefficient, D, shows variation with the soil depth and its value differs from one geophysical location to another. A constant soil–air interface transfer coefficient is calculated and the soil–air radon flux is accordingly estimated. In addition, the surface radon concentrations at the soil–air interface are calculated from the model and compared against extrapolated field data.
{"title":"Finite element modeling of radon distribution in natural soils of different geophysical regions","authors":"Y. Hafez, E. Awad","doi":"10.1080/23311940.2016.1254859","DOIUrl":"https://doi.org/10.1080/23311940.2016.1254859","url":null,"abstract":"Abstract Radon migration from deep soil to the earth’s surface is investigated numerically using a developed Finite Element numerical model. The objectives of this study are: to predict the radon profile variation with the soil depth, the radon diffusion coefficients in multi-layer soils, the surface radon concentrations, and the soil–air radon fluxes. The flexibility of the Finite Element Method allows for accommodating varying diffusion coefficients in multi-layer soils and expressing convective-type boundary conditions. The convective-type boundary condition assumes that the surface radon flux is proportional to the difference between the radon concentration in the ambient air and the radon concentration at the soil surface. Radon concentration profiles with depth were collected from several geophysical locations such as Greece, Germany, South Africa, and Jordan. The numerical results show that the multi-layer profile of radon in natural soils is more descriptive than the one-layer one used traditionally, where each layer has its own diffusion coefficient. The effective diffusion coefficient, D, shows variation with the soil depth and its value differs from one geophysical location to another. A constant soil–air interface transfer coefficient is calculated and the soil–air radon flux is accordingly estimated. In addition, the surface radon concentrations at the soil–air interface are calculated from the model and compared against extrapolated field data.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2016.1254859","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60084721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-12-31DOI: 10.1080/23311940.2016.1262572
P. B. Nalle, S. S. Deshmukh, R. Dorik, K. M. Jadhav
Abstract The ultrasonic velocity (U), density (ρ), and viscosity (η) of an ethanolic extract of drug Piper nigrum with MgCl2 (metal ions) have been measured as a function of the number of moles n = (0.7009, 1.4018, 2.1027, 2.8036 and 3.5045) at 303.15, 308.15, 313.15 and 318.15 K temperature. Various thermoacoustic and their excess values such as adiabatic compressibilities (β), intermolecular free lengths (Lf), excess adiabatic compressibility (βE), excess intermolecular free length () have been computed using values of ultrasonic velocity (U), density (ρ), and viscosity (η). The excess values of ultrasonic velocity, specific acoustic impedance are positive, whereas isentropic compressibility and intermolecular free lengths are negative over the entire composition range of MgCl2 + P. nigrum which indicates the presence of specific interactions between unlike molecules. Molecular association is reflected by ultrasonic investigation. This may be interpreted due to the of complex formation. The chemical interaction may involve the association due to the solute–solvent and ion–solvent interaction and due to the formation of charge-transfer complexes, which is useful to understand the mechanism of their metabolism in living systems. The results obtained from these studies are helpful for pharmacological applications of drugs, transport of drugs across biological membranes.
摘要在303.15、308.15、313.15和318.15 K温度下，测定了含MgCl2(金属离子)的黑胡椒醇提物的超声速度(U)、密度(ρ)和粘度(η)与摩尔数n =(0.7009、1.4018、2.1027、2.8036和3.5045)的关系。利用超声速度(U)、密度(ρ)和粘度(η)的值，计算了各种热声及其超值，如绝热压缩系数(β)、分子间自由长度(Lf)、超绝热压缩系数(β e)、超分子间自由长度()。在MgCl2 + P. nigrum的整个组成范围内，超声速度、比声阻抗的超值为正，而等熵压缩率和分子间自由长度为负，表明不同分子之间存在特定的相互作用。分子结合是通过超声检查来反映的。这可以解释为复杂的地层。化学相互作用可能包括溶质-溶剂和离子-溶剂相互作用以及电荷转移配合物的形成，这有助于了解它们在生命系统中的代谢机制。这些研究结果有助于药物的药理应用和药物跨生物膜的转运。
{"title":"Effect of drug Piper nigrum on magnesium chloride at varying concentration and temperature through ultrasonic method: A thermoacoustic study","authors":"P. B. Nalle, S. S. Deshmukh, R. Dorik, K. M. Jadhav","doi":"10.1080/23311940.2016.1262572","DOIUrl":"https://doi.org/10.1080/23311940.2016.1262572","url":null,"abstract":"Abstract The ultrasonic velocity (U), density (ρ), and viscosity (η) of an ethanolic extract of drug Piper nigrum with MgCl2 (metal ions) have been measured as a function of the number of moles n = (0.7009, 1.4018, 2.1027, 2.8036 and 3.5045) at 303.15, 308.15, 313.15 and 318.15 K temperature. Various thermoacoustic and their excess values such as adiabatic compressibilities (β), intermolecular free lengths (Lf), excess adiabatic compressibility (βE), excess intermolecular free length () have been computed using values of ultrasonic velocity (U), density (ρ), and viscosity (η). The excess values of ultrasonic velocity, specific acoustic impedance are positive, whereas isentropic compressibility and intermolecular free lengths are negative over the entire composition range of MgCl2 + P. nigrum which indicates the presence of specific interactions between unlike molecules. Molecular association is reflected by ultrasonic investigation. This may be interpreted due to the of complex formation. The chemical interaction may involve the association due to the solute–solvent and ion–solvent interaction and due to the formation of charge-transfer complexes, which is useful to understand the mechanism of their metabolism in living systems. The results obtained from these studies are helpful for pharmacological applications of drugs, transport of drugs across biological membranes.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2016.1262572","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60084757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract A series of trivalent europium-doped M3SiO5 (M = Sr, Ca and Mg) phosphors were synthesized using sol–gel process at 950°C. Samples were further reheated at high temperature to study the effect of reheating on crystal structure and optical characteristics. X-ray diffraction measurement of these materials was carried out to know the crystal structure. Diffraction pattern showed monoclinic structure having space group Cm for Ca3SiO5 materials. However, tetragonal phase with space group P4/ncc was observed for Sr3SiO5 materials. Mg3SiO5 material show mixed diffraction peaks at 950 and 1,150°C. Transmission electron microscopic analysis was used to estimate the particle size of silicates. Photoluminescence emission spectra were recorded to check the luminescence properties of prepared materials. These phosphors exhibited a strong orange-red light under excitation at 395 nm. The prepared phosphors exhibited most intense peak in 610–620 nm region due to the 5D0→7F2 transition of europium (III) ion available in lattice. To overcome the deficiency of red silicates, M3SiO5 materials were explored and they might be integrated with ultraviolet LEDs to generate light which may be suitable for display applications.
{"title":"Optical characteristics of sol-gel derived M3SiO5:Eu3+ (M = Sr, Ca and Mg) nanophosphors for display device technology","authors":"Devender Singh, Suman Sheoran, Shri Bhagwan, Sonika Kadyan","doi":"10.1080/23311940.2016.1262573","DOIUrl":"https://doi.org/10.1080/23311940.2016.1262573","url":null,"abstract":"Abstract A series of trivalent europium-doped M3SiO5 (M = Sr, Ca and Mg) phosphors were synthesized using sol–gel process at 950°C. Samples were further reheated at high temperature to study the effect of reheating on crystal structure and optical characteristics. X-ray diffraction measurement of these materials was carried out to know the crystal structure. Diffraction pattern showed monoclinic structure having space group Cm for Ca3SiO5 materials. However, tetragonal phase with space group P4/ncc was observed for Sr3SiO5 materials. Mg3SiO5 material show mixed diffraction peaks at 950 and 1,150°C. Transmission electron microscopic analysis was used to estimate the particle size of silicates. Photoluminescence emission spectra were recorded to check the luminescence properties of prepared materials. These phosphors exhibited a strong orange-red light under excitation at 395 nm. The prepared phosphors exhibited most intense peak in 610–620 nm region due to the 5D0→7F2 transition of europium (III) ion available in lattice. To overcome the deficiency of red silicates, M3SiO5 materials were explored and they might be integrated with ultraviolet LEDs to generate light which may be suitable for display applications.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2016.1262573","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60084768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-12-31DOI: 10.1080/23311940.2016.1265779
U. Chowdhury, M. A. Rahman, M. A. Rahman, M. Bhuiyan
Abstract Using the plane-wave ultrasoft pseudo-potential technique, which is based on the first-principle density functional theory with generalized gradient approximation, the structural, elastic, electronic, and optical properties of FeSe are investigated. The calculated structural parameters show a good agreement with the experimental and other theoretical results. The optimized lattice parameters, independent elastic constants (C11, C12, C13, C33, C44, and C66), bulk modulus B, compressibility K, shear modulus G, and Poisson’s ratio ν, as well as the band structures, total and atom projected densities of states, and finally the optical properties of FeSe have been evaluated and discussed. The band structure and density of states show that this phase has metallic behavior and the major contribution comes from Fe-3d states. Further, the first time investigated optical functions reveal that the reflectivity is high in the IR-UV region up to 19.5 eV, showing this to be promising coating material.
{"title":"Ab-initio study on structural, elastic, electronic and optical properties of iron-based superconductor","authors":"U. Chowdhury, M. A. Rahman, M. A. Rahman, M. Bhuiyan","doi":"10.1080/23311940.2016.1265779","DOIUrl":"https://doi.org/10.1080/23311940.2016.1265779","url":null,"abstract":"Abstract Using the plane-wave ultrasoft pseudo-potential technique, which is based on the first-principle density functional theory with generalized gradient approximation, the structural, elastic, electronic, and optical properties of FeSe are investigated. The calculated structural parameters show a good agreement with the experimental and other theoretical results. The optimized lattice parameters, independent elastic constants (C11, C12, C13, C33, C44, and C66), bulk modulus B, compressibility K, shear modulus G, and Poisson’s ratio ν, as well as the band structures, total and atom projected densities of states, and finally the optical properties of FeSe have been evaluated and discussed. The band structure and density of states show that this phase has metallic behavior and the major contribution comes from Fe-3d states. Further, the first time investigated optical functions reveal that the reflectivity is high in the IR-UV region up to 19.5 eV, showing this to be promising coating material.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2016.1265779","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60084814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-12-31DOI: 10.1080/23311940.2016.1249542
K. Vieira
Within hours of the first data release of the Gaia space astrometry mission, a paper in the arXiv repository appeared with results based on it. “First Gaia local group dynamics: Magellanic Clouds proper motion and rotation” by van der Marel and Sahlmann (http://arxiv.org/abs/1609.04395) simply reveals how eager astronomers are to explore and exploit the exquisite parallaxes and proper motions promised by this ESA space mission. The Gaia era has started.
在盖亚太空天体测量任务的第一次数据发布的几个小时内，arXiv存储库中出现了一篇基于它的结果的论文。van der Marel和Sahlmann的“第一个盖亚本地群体动力学:麦哲伦云的固有运动和旋转”(http://arxiv.org/abs/1609.04395)简单地揭示了天文学家是多么渴望探索和利用ESA太空任务所承诺的精致视差和固有运动。盖亚时代已经开始。
{"title":"The Gaia era has started","authors":"K. Vieira","doi":"10.1080/23311940.2016.1249542","DOIUrl":"https://doi.org/10.1080/23311940.2016.1249542","url":null,"abstract":"Within hours of the first data release of the Gaia space astrometry mission, a paper in the arXiv repository appeared with results based on it. “First Gaia local group dynamics: Magellanic Clouds proper motion and rotation” by van der Marel and Sahlmann (http://arxiv.org/abs/1609.04395) simply reveals how eager astronomers are to explore and exploit the exquisite parallaxes and proper motions promised by this ESA space mission. The Gaia era has started.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2016.1249542","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60084716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-12-31DOI: 10.1080/23311940.2016.1247486
A. Suriani, A. Dalila, A. Mohamed, M. S. Rosmi, M. Mamat, M. F. Malek, M. Ahmad, N. Hashim, I. Isa, T. Soga, M. Tanemura
Abstract High-quality vertically aligned carbon nanotubes (VACNTs) were synthesised using ferrocene-chicken oil mixture utilising a thermal chemical vapour deposition (TCVD) method. Reaction parameters including vaporisation temperature, catalyst concentration and synthesis time were examined for the first time to investigate their influence on the growth of VACNTs. Analysis via field emission scanning electron microscopy and micro-Raman spectroscopy revealed that the growth rate, diameter and crystallinity of VACNTs depend on the varied synthesis parameters. Vaporisation temperature of 570°C, catalyst concentration of 5.33 wt% and synthesis time of 60 min were considered as optimum parameters for the production of VACNTs from waste chicken fat. These parameters are able to produce VACNTs with small diameters in the range of 15–30 nm and good quality (ID/IG ~ 0.39 and purity ~76%) which were comparable to those synthesised using conventional carbon precursor. The low turn on and threshold fields of VACNTs synthesised using optimum parameters indicated that the VACNTs synthesised using waste chicken fat are good candidate for field electron emitter. The result of this study therefore can be used to optimise the growth and production of VACNTs from waste chicken fat in a large scale for field emission application.
{"title":"Parametric study of waste chicken fat catalytic chemical vapour deposition for controlled synthesis of vertically aligned carbon nanotubes","authors":"A. Suriani, A. Dalila, A. Mohamed, M. S. Rosmi, M. Mamat, M. F. Malek, M. Ahmad, N. Hashim, I. Isa, T. Soga, M. Tanemura","doi":"10.1080/23311940.2016.1247486","DOIUrl":"https://doi.org/10.1080/23311940.2016.1247486","url":null,"abstract":"Abstract High-quality vertically aligned carbon nanotubes (VACNTs) were synthesised using ferrocene-chicken oil mixture utilising a thermal chemical vapour deposition (TCVD) method. Reaction parameters including vaporisation temperature, catalyst concentration and synthesis time were examined for the first time to investigate their influence on the growth of VACNTs. Analysis via field emission scanning electron microscopy and micro-Raman spectroscopy revealed that the growth rate, diameter and crystallinity of VACNTs depend on the varied synthesis parameters. Vaporisation temperature of 570°C, catalyst concentration of 5.33 wt% and synthesis time of 60 min were considered as optimum parameters for the production of VACNTs from waste chicken fat. These parameters are able to produce VACNTs with small diameters in the range of 15–30 nm and good quality (ID/IG ~ 0.39 and purity ~76%) which were comparable to those synthesised using conventional carbon precursor. The low turn on and threshold fields of VACNTs synthesised using optimum parameters indicated that the VACNTs synthesised using waste chicken fat are good candidate for field electron emitter. The result of this study therefore can be used to optimise the growth and production of VACNTs from waste chicken fat in a large scale for field emission application.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2016.1247486","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60084705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-12-23DOI: 10.1080/23311940.2016.1265778
Md. Tofajjol Hossen Bhuiyan, M. A. Rahman, Md Atikur Rahman, R. Sultana, M. R. Mostafa., Asmaul Husna Tania, M. R. Sarker
Abstract High-quality cobalt vanadate crystals have been synthesized by solid-state reaction route. Structure and morphology of the synthesized powders were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) spectroscopy. The XRD patterns revealed that the as prepared materials are of high crystallinity and high quality. The SEM images showed that the crystalline CoV2O6 material is very uniform and well separated, with particle (of) area ~252 μm. The electronic and optical properties were investigated by impedance analyzer and UV–visible spectrophotometer. Temperature-dependent electrical resistivity was measured using four-probe technique. The crystalline CoV2O6 material is a semiconductor and its activation energy is 0.05 eV.
{"title":"Synthesis and characterization of high-quality cobalt vanadate crystals and their applications in lithium-ion batteries","authors":"Md. Tofajjol Hossen Bhuiyan, M. A. Rahman, Md Atikur Rahman, R. Sultana, M. R. Mostafa., Asmaul Husna Tania, M. R. Sarker","doi":"10.1080/23311940.2016.1265778","DOIUrl":"https://doi.org/10.1080/23311940.2016.1265778","url":null,"abstract":"Abstract High-quality cobalt vanadate crystals have been synthesized by solid-state reaction route. Structure and morphology of the synthesized powders were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) spectroscopy. The XRD patterns revealed that the as prepared materials are of high crystallinity and high quality. The SEM images showed that the crystalline CoV2O6 material is very uniform and well separated, with particle (of) area ~252 μm. The electronic and optical properties were investigated by impedance analyzer and UV–visible spectrophotometer. Temperature-dependent electrical resistivity was measured using four-probe technique. The crystalline CoV2O6 material is a semiconductor and its activation energy is 0.05 eV.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2016.1265778","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60084810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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