Cogent Physics最新文献_第2页

Ab-initio study of C15-type Laves phase superconductor LaRu2 C15型Laves相超导体LaRu2的从头算研究

Cogent Physics Pub Date : 2017-01-01 DOI: 10.1080/23311940.2017.1360461

Md. Ibrahim Kholil, Md. Shahinur Islam, M. A. Rahman

{"title":"Ab-initio study of C15-type Laves phase superconductor LaRu2","authors":"Md. Ibrahim Kholil, Md. Shahinur Islam, M. A. Rahman","doi":"10.1080/23311940.2017.1360461","DOIUrl":"https://doi.org/10.1080/23311940.2017.1360461","url":null,"abstract":"Abstract Structural, elastic, electronic, optical, thermodynamic, and superconducting properties of the Laves phase superconductor LaRu2 with Tc ~ 1.63 K were investigated using the first-principles calculations for the first time. The corresponding evaluated structural parameters are in good agreement with the available theoretical values. The different elastic properties like as, elastic constants, bulk modulus B, shear modulus G, Young’s modulus E, and Poisson ratio ν were calculated using the Voigt–Reuss–Hill approximation. The ductility nature appears in both values of Cauchy pressure and Pugh’s ratio. The band structure and Cauchy pressure shows that the material behaves metallic nature. The calculated total density of state is 6.80 (electrons/eV) of LaRu2. The optical properties such as reflectivity, absorption spectrum, refractive index, dielectric function, conductivity, and energy loss spectrum are also calculated. The photoconductivity reveals the metallic nature of LaRu2 and absorption coefficient is good in the infrared region. The evaluated density and Debye temperature are 9.55 gm/cm3 and 110.51 K, respectively. In addition, the study of thermodynamic properties like as minimum thermal conductivity, melting temperature, and Dulong–Petit limit are 0.26 (Wm−1 K−1), 1,471.65 K, and 74.80 (J/mole K), respectively. Finally, the investigated electron-phonon coupling constant is 0.66 of LaRu2 superconductor.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2017.1360461","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42307780","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}

引用次数: 2

RT-TDDFT study of hole oscillations in B-DNA monomers and dimers B-DNA单体和二聚体空穴振荡的RT-TDDFT研究

Cogent Physics Pub Date : 2017-01-01 DOI: 10.1080/23311940.2017.1361077

M. Tassi, A. Morphis, K. Lambropoulos, C. Simserides

引用次数: 14

Near-zero thermal expansion in magnetically ordered state in dysprosium at high pressures and low temperatures 镝在高压和低温下磁有序态的近零热膨胀

Cogent Physics Pub Date : 2017-01-01 DOI: 10.1080/23311940.2017.1412107

Kevin M. Hope, G. Samudrala, Y. Vohra

引用次数: 3

Does Birkhoff’s theorem really hold? 伯克霍夫定理真的成立吗?

Cogent Physics Pub Date : 2017-01-01 DOI: 10.1080/23311940.2017.1357325

Wenbin Lin

引用次数: 0

Radioactivity in wild-growing mushrooms of the Calabria region, south of Italy 意大利南部卡拉布里亚地区野生蘑菇的放射性

Cogent Physics Pub Date : 2017-01-01 DOI: 10.1080/23311940.2017.1354957

F. Caridi, G. Belmusto

{"title":"Radioactivity in wild-growing mushrooms of the Calabria region, south of Italy","authors":"F. Caridi, G. Belmusto","doi":"10.1080/23311940.2017.1354957","DOIUrl":"https://doi.org/10.1080/23311940.2017.1354957","url":null,"abstract":"Abstract Wild-growing mushrooms are a complementary foodstuff, widely consumed as a delicacy, in Italy. They are considered excellent bioindicators of environmental pollution and the accumulation of radionuclides can pose a radiological hazard. 137Cs and 40K activity concentrations were measured through HPGe gamma-spectrometry in different mushroom species (Agaricus arvensis, Leccinum quercinum, Boletus aereus, Lactarius deliciosus, Boletus edulis, Macrolepiota konradii, Cantharellus lutescens) collected from four different sampling sites in the Calabria region, south of Italy. Experimental values were found to be in the range from (0.3 ± 0.1) Bq/kg f.m. (fresh mass) to (73.1 ± 4.6) Bq/kg f.m. for 137Cs and from (46.9 ± 10.7) Bq/kg f.m. to (161.3 ± 12.9) Bq/kg f.m. for 40K, respectively. All values were much lower than the specific activity limit set by the international legislation at 600 Bq/kg f.m. for 137Cs and at 1,258 Bq/kg f.m. for 40K, respectively. Experimental activity concentrations allowed us to determine the effective dose due to the ingestion of mushrooms by adult members of the population. It was found in the range from 0.25 to 1.35 μSv/y, much lower than the recommended level for the public (1 mSv/y). Data obtained in this article provide useful information on the environmental risk and can be further used for a radiological mapping of the studied area.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2017.1354957","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41573250","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}

引用次数: 3

Closed form solutions of complex wave equations via the modified simple equation method 用改进的简单方程法求解复杂波动方程的封闭形式

Cogent Physics Pub Date : 2017-01-01 DOI: 10.1080/23311940.2017.1312751

A. Hossain, M. Akbar, A. Wazwaz

引用次数: 23

Closed form wave solutions of two nonlinear evolution equations 两个非线性发展方程的闭型波解

Cogent Physics Pub Date : 2017-01-01 DOI: 10.1080/23311940.2017.1396948

A. Hossain, M. Akbar, M. Azad

引用次数: 6

Tailoring the electronic structure and optical properties of cadmium-doped zinc oxides nanosheet 定制镉掺杂氧化锌纳米片的电子结构和光学性能

Cogent Physics Pub Date : 2017-01-01 DOI: 10.1080/23311940.2017.1391734

Saleem Ayaz Khan, S. Azam, M. Kanoun, G. Murtaza, M. Rani, S. Goumri‐Said

{"title":"Tailoring the electronic structure and optical properties of cadmium-doped zinc oxides nanosheet","authors":"Saleem Ayaz Khan, S. Azam, M. Kanoun, G. Murtaza, M. Rani, S. Goumri‐Said","doi":"10.1080/23311940.2017.1391734","DOIUrl":"https://doi.org/10.1080/23311940.2017.1391734","url":null,"abstract":"Abstract Cd-doped ZnO nanosheet (ZnO NS) were investigated using a full-potential linearized augmented plane wave method within the generalized gradient approximation (GGA) to calculate the electronic structure and its optical response. The calculated band structures have shown that the Cd-doped ZnO NS is a direct band gap semiconductor at Γ with 1.50 eV band gap. The contribution of each atom/orbital were commented in light of total and partial densities of states. We also derived the optical constants (mainly the dielectric constants ε1(0) and ε2(0)), the absorption coefficient I(ω), refractive index n(ω), extinction coefficient k(ω), and energy-loss function L(ω). The spectrum of absorption coefficient has revealed to increase rapidly for photon energies higher than 2.5 eV. The absorption spectrum was found to be limited in energy region due to different contributions electronic transitions that occurred within ZnO NS and effect of Cd doping. Reducing the band gap of ZnO NS to low values is suitable process for light-emitting devices and solar cells applications.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2017.1391734","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48275393","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}

引用次数: 13

High-pressure structural parameters and equation of state of osmium to 207 GPa 锇到207GPa的高压结构参数和状态方程

Cogent Physics Pub Date : 2017-01-01 DOI: 10.1080/23311940.2017.1376899

Christopher S. Perreault, N. Velisavljevic, Y. Vohra

{"title":"High-pressure structural parameters and equation of state of osmium to 207 GPa","authors":"Christopher S. Perreault, N. Velisavljevic, Y. Vohra","doi":"10.1080/23311940.2017.1376899","DOIUrl":"https://doi.org/10.1080/23311940.2017.1376899","url":null,"abstract":"Abstract The most incompressible transition metal osmium (Os) has been studied under high pressure. There is significant interest in Os because of the structural anomalies attributed to topological transitions in the Fermi surface for valence electrons in the hexagonal close-packed phase. We report on measurements of structural parameters and equation of state on Os metal to a pressure of 207 GPa at ambient temperature using platinum as a pressure standard. We obtained angle-dispersive X-ray diffraction data at a synchrotron source with closely spaced pressure intervals to observe any discontinuities or anomalies in the axial c/a ratio at high pressures. Rietveld refinements of X-ray diffraction data show a slowly varying axial ratio (c/a) with a broad minimum at 75 GPa. Our data do not provide any evidence of anomalous behavior in the c/a ratio in Os at 25 or 150 GPa as have been reported in previous studies. Our experimental results are in agreement with theoretical calculations that do not predict any anomalous behavior in c/a ratio in Os under extreme conditions. We present an equation of state for Os to 207 GPa (V/V0 = 0.761) at ambient temperature and compare our results with the previously published data.","PeriodicalId":43050,"journal":{"name":"Cogent Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311940.2017.1376899","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44484218","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}

引用次数: 11

Electronic origin of melting T–P curves of alkali metals with negative slope and minimum 具有负斜率和最小值的碱金属熔化T–P曲线的电子起源

Cogent Physics Pub Date : 2017-01-01 DOI: 10.1080/23311940.2017.1327697

V. Degtyareva

引用次数: 1