检索结果-内蒙古大学图书馆

Electrical conductivity and dielectric study of zinc substituted tellurovanadate glass systems

Ceramics International 2025年

作者： Athokpam, sushma madolappa, shivanand Fernandes, Brian Jeevan Ram.s., K. Ram.s., K.P. mallikarjunaiah, K.J. Department of Physics M.S. Ramaiah University of Applied Sciences Bengaluru560058 India Department of Physics Indian Institute of Science Bengaluru560012 India

Impedance spectroscopy is a powerful tool in understanding the conduction mechanism in materials. In the present study, xZnO.(60−x)TeO2.40V2O5 (x = 20, 25, 30, 35, 40 mol%) glasses were synthesized using the conventional melt-quenching method. The effect of ZnO on the dielectric constant, electric modulus and complex impedance spectra was studied using impedance spectroscopy. This study permits us to understand the microscopic processes responsible for the electric response and the relaxation behaviour observed in the material. The present investigation was carried out over a wide frequency range (40 Hz−20 mHz) and various temperatures from 30 to 250 °C. The data obtained from the impedance analyzer in R-C mode were converted to the desired parameters using the standard relations. The Nyquist plot revealed two semicircles, indicating the contribution from the bulk and the glass/electrode interface. The observation of a depressed semicircle revealed the existence of a non-Debye-type relaxation process. The dc conductivity was found to decrease with an increase in ZnO from ∼10−3 s m−1 at 20TVZ to ∼10−5 s m−1 at 40TVZ. Relaxation tim.s.obtained from the frequency explicit plots of the imaginary part of the impedance (Z″) and electric modulus (m″) follows Arrhenius's law. The fluctuating behaviour of activation energy with ZnO concentration is attributed to the combined effect of ionic and electronic conduction mechanisms observed in the system. A comparison between dielectric loss (tan δ), Z″ and m″ inferred the presence of both long-range conductivity and dipole relaxation mechanisms in the present glass system. © 2025 Elsevier Ltd and Techna Group s.r.l.

关键词： Dielectric losses

来源：评论

学校读者我要写书评

暂无评论

Anomalous properties of spark plasma sintered boron nitride solids

引用

materials Today 2025年 86卷 42-51页

作者： Biswas, Abhijit serles, Peter Alvarez, Gustavo A. schimpf, Jesse Hache, michel Kong, Jonathan Demingos, Pedro Guerra Yuan, Bo Pieshkov, Tymofii s. Li, Chenxi Puthirath, Anand B. Gao, Bin Gray, Tia Zhang, Xiang murukeshan, Jishnu Vajtai, Robert Dai, Pengcheng singh, Chandra Veer Howe, Jane Zou, Yu martin, Lane W. Clancy, Jam.s.Patrick Tian, Zhiting Filleter, Tobin Ajayan, Pulickel m. Department of Materials Science and Nanoengineering Rice University HoustonTX77005 United States Department of Mechanical & Industrial Engineering University of Toronto 5 King's College Road TorontoM5S 3G8 Canada Sibley School of Mechanical and Aerospace Engineering Cornell University IthacaNY14853 United States Department of Materials Science and Engineering University of California Berkeley94720 United States Department of Materials Science and Engineering University of Toronto 184 College St TorontoM5S 3E4 Canada Department of Physics and Astronomy McMaster University HamiltonL8S 4M1 Canada Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Department of Physics and Astronomy Rice University HoustonTX77005 United States Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley94720 United States

Hexagonal boron nitride (h-BN) is a brittle ceramic with a layered structure, however, recent experiments have suggested that inter-layer structural engineering could be key to new structural and functional properties. Here we report the scalable bulk synthesis of high-density crystalline h-BN solids, by using high-temperature spark plasma sintering (sPs) of h-BN powders, which show high values of mechanical strength, ductility, dielectric constant, thermal conductivity, and exceptional neutron radiation shielding capability. Through exhaustive characterizations we reveal that sPs induces non-basal plane crystallinity, twisting of layers, and facilitates inter-grain fusion with a high degree of in-plane alignment across macroscale dimensions, resulting in near-theoretical density and improved properties. Our findings highlight the importance of material design, via new approaches such as layer twisting and interlayer interconnections, to create novel ceramics with properties that could go beyond their intrinsic limits. © 2025

关键词： Ductility

来源：评论

学校读者我要写书评

暂无评论

Characterisation of Hβ spectra from EXO 051910+3737.7 X-rays binaries

arXiv

引用

arXiv 2025年

作者： Nuchvanichakul, Pornisara Irawati, Puji Rittipruk, Pakakaew Gandhi, Poshak Knigge, Christian Charles, Phil Wannawichian, suwicha M.S. Program in Applied Physics Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai50200 Thailand Department of Physics and Astronomy University of Southampton Southampton United Kingdom National Astronomical Research Institute of Thailand Chiang Mai50180 Thailand Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai50200 Thailand

We investigate the spectral characteristics of the Be/X-ray binary system, EXO 051910+3737.7, in which Be/X-ray systems are the largest sub-class of high-m.s. X-ray binaries. spectroscopic observations are taken by the Thai National Telescope (TNT) with a medium-REsolution spectrograph (mREs) instrument for seven nights spanning from 2020 to 2021. Our primary focus is directed towards the analysis of two Balmer lines, namely Hα and Hβ, given that Be stars typically exhibit em.s.ion features in at least one of these hydrogen Balmer lines during certain phases. Our observations reveal split Balmer em.s.ion lines throughout the entire duration of our monitoring. Double Gaussian profiles were employed for line fitting to characterize these lines. The presence of double peaks in the Balmer lines indicates the presence of asymmetries within the circumstellar disc. We then analyze V/R variations and the changes in Hβ spectra. Our analysis of V/R variation which Violet (V) and Red (R) peak intensity components, revealed rapid fluctuations occurring within a single day, although determining the precise periodicity was constrained by instrumental limitations and the duration of observability. Furthermore, employing observed the wavelength differences (∆λ) in conjunction with typical Be star parameters allowed us to estimate the radius (rβ) of the Hβ emitting envelope. The average value was calculated to be 2.585r∗, with a standard deviation of 0.050r∗ © 2025, CC BY-NC-ND.

关键词： stars

来源：评论

学校读者我要写书评

暂无评论

Cu₂sns₃ nano-spheres as a potent therapeutic agents: exploring their antibacterial, antioxidant, and cytotoxic competencies

引用

Journal of Nanoparticle Research 2025年第2期27卷 1-21页

作者： Raval, Jolly B. Chaki, sunil H. Patel, sefali R. Vaidya, Yati H. Khimani, Ankurkumar J. Thakor, Parth Thakkar, Anjali B. Deshpande, milind P. P. G. Department of Physics Sardar Patel University Gujarat VallabhVidyanagar388120 India Department of Microbiology Shri A. N. Patel P. G. Institute of Science and Research Gujarat Anand388001 India Department of Physics Shri A. N. Patel P. G. Institute of Science and Research Gujarat Anand388001 India B. D. Patel Institute of Paramedical Sciences Charotar University of Science and Technology CHARUSAT Campus Gujarat Changa388421 India Department of Applied & Interdisciplinary Sciences CISST Sardar Patel University Gujarat Vallabh Vidyanagar388120 India P. G. Department of Biosciences Sardar Patel University Satellite Campus Bakrol-Vadtal Road Gujarat Bakrol388315 India Department of Applied Physics Faculty of Technology and Engineering The M.S. University of Baroda Gujarat Vadodara390002 India

Cu₂sns₃ (CTs) is potent substitute for conventional compounds due to adjustable bandgap, conductivity of p-type, adaptable morphology, easy to synthesize, and superior thermoelectric properties. In this work, the CTs nano-spheres are synthesized by hydrothermal technique. The synthesized CTs nano-spheres are employed for the antibacterial, antioxidant, and cytotoxic application. structural analysis by X-ray diffraction confirms cubic unit cell structure of CTs nano-spheres. The energy-dispersive X-ray analysis showed CTs nano-spheres to be copper-rich and tin-deficient. scanning electron microscopy images revealed nano-spheres with needle-like surface features. The CTs nano-spheres possess direct bandgap of 1.58 eV, confirmed by diffuse reflectance spectroscopy. The antibacterial activity shows 100% activity index with higher zone of inhibition in Listeria monocytogenes and staphylococcus aureus. The antioxidant activity of CTs nano-spheres determined using the DPPH assay showed IC50 value of 61.60 µg/ml stating moderate antioxidant efficiency. The in vitro cytotoxic analysis is carried out by employing A549 lung cancer cell lines. The in vivo and vitro cytotoxic analysis provided the potent cytotoxicity of CTs nano-spheres, as reflected in LC50 value of 40.40 µg/ml and IC50 value of 57.75 ± 2.34 μg/ml. The mechanistic evolution of CTs nano-spheres for their antibacterial activity is proposed in this work. The leaching behaviour of CTs nano-spheres revealed higher leaching of sn4+ ions than Cu+ ions, contributing to their strong antibacterial activity. The zeta potential of CTs nano-spheres is found to be − 30.70 mV, which showed less agglomeration of CTs nano-spheres, depicting an efficient antibacterial activity. The obtained results are rigorously analysed and supported with relevant data. © The Author(s), under exclusive licence to springer Nature B.V. 2025.

关键词： X ray diffraction analysis

来源：评论

学校读者我要写书评

暂无评论

THERmO-LUmINEsCENCE OF KBR-TL AROUND ROOm-TEmPERATURE

引用

JAPANEsE JOURNAL OF applied physics 1981年第6期20卷 1069-1072页

作者： JOsHI, RV CHAUDHARI, RT Applied Physics Department Faculty of Technology and Engineering M.S. University of Baroda

Thermal glow curves of KBr: Tl phosphors were investigated after irradiation with ultraviolet light or X-rays at room temperature. It was found that the specimens exhibited a single glow peak in the temperature range of 340–370 K, the position of the maximum of which depended on the history of the sample. Present work included the effects on the thermoluminescent characteristics of the phosphor when subjected to various thermal and/or mechanical treatments. It is proposed that the Tl+ ion-anion vacancy pair situated in the perfect region of the lattice is responsible for the peak at 370 K. shift in the peak position to lower temperature side is attributed to the Tl+ ion-anion vacancy pair in the distorted region of the lattice, the distortion being caused by the vacancy cluster in the neighbourhood of the pair.

关键词：

来源：评论

学校读者我要写书评

暂无评论

EFFECT OF BA-2+ AND CA-2+ ImPURITIEs ON THE THERmALLY sTImULATED LUmINEsCENCE OF sODIUm-CHLORIDE

引用

JOURNAL OF LUmINEsCENCE 1984年第DEC期31-2卷 142-144页

作者： JOsHI, RV JOsHI, TR mAHAJAN, OH KATHURIA, sP NEHATE, AK Applied Physics Department Faculty of Technology and Engineering M.S. University of Baroda Baroda-390 001 India

sodium Chloride specimens doped with Ba 2+ and Ca 2+ impurities were examined for their thermoluminescent behaviour after exposure to gamma radiation. Effect of variation in Ba concentration on NaCl:Ba for fixed irradiation dose (800R) and of change in the radiation dose on NaCl:Ca for fixed Ca concentration have been investigated.

关键词： sODIUm CHLORIDE

来源：评论

学校读者我要写书评

暂无评论

INVEsTIGATION OF ULTRAsONIC VELOCITY AND RELATED PARAmETERs IN LIQUID-CRYsTALLINE mIXTUREs

引用

mOLECULAR CRYsTALs AND LIQUID CRYsTALs 1980年第4期60卷 297-310页

作者： GEORGE, AK VORA, RA PADmINI, ARKL Applied Physics Department Faculty of Technology and Engineering M.S. University of Baroda Baroda 390 001 India. Applied Chemistry Department Faculty of Technology and Engineering M.S. University of Baroda Baroda 390 001 India.

Investigations of ultrasonic velocity, specific volume and related parameters were carried out in a mixture ofp-n-butoxybenzylidene-p-chloroaniline (BBCA) andp-anisal-p-toluidine (pApT) at eight different concentrations. BBCA exhibits polymorphism with two smectic phases, viz., smectic B and smectic A, whilepApT is non-m.s.morphic. All the mixtures studied were nematic, the m.s.morphism vanishes below 34.3 mole percent of BBCA. specific volume showed a large increase in the vicinity of the phase transition and the ultrasonic velocity showed an abrupt minimum near the transition. The adiabatic compressibility showed a maximum near the phase transition. It was found that the dip in ultrasonic velocity, change in specific volume and the jump in adiabatic compressibility at the transition decreases with increasing concentration of the non-m.s.morphic compound. The parameter, viz., molar sound velocity was also estimated. The coefficient of thermal expansion and adiabatic compressibility were also estimated and they were found to attain very high values near the phase transition. The experimental results are explained on the basis of de Gennes theory of pre-transitional effects generalized by Bendler. The critical exponents are estimated in the isotropic as well as in the nematic phases.

关键词： CRYsTALs, LIQUID

来源：评论

学校读者我要写书评

暂无评论

sTUDY OF THERmAL GLOW CURVEs OF KC1-BA EXPOsED TO DIFFERENT RADIATIONs

引用

JOURNAL OF LUmINEsCENCE 1988年第C期40-1卷 852-853页

作者： AKOLEKAR, ms JOsHI, TR JOsHI, RV PRAsAD, LHH DHAKE, KP Applied Physics Department Faculty of Technology and Engineering M.S. University of Baroda Baroda 390 001 India

Examination of the KC1: Ba glow curves after thermal pretreatment and exposure to different radiations sheds adequate light on the nature of the associated thermoluminescene centres.

关键词： POTAssIUm COmPOUNDs

来源：评论

学校读者我要写书评

暂无评论

TRIBOTHERmOLUmINEsCENCE IN NACL-CA (T) DOsImETRY mATERIAL

引用

JOURNAL OF LUmINEsCENCE 1988年第C期40-1卷 854-855页

作者： NEHATE, AK DHAKE, KP JOsHI, TR Applied Physics Department Faculty of Technology and Engineering M.S. University of Baroda Baroda 390 001 India

Previously reported NaC1: Ca dosimetry material is discussed for its spurious thermoluminescence. The spurious TL is shown to have no influence on UV dosimetry measurements.

关键词： sODIUm CHLORIDE

来源：评论

学校读者我要写书评

暂无评论

Experimental evidence for power-law wave number spectra of fractal tracer distributions in a complicated surface flow

引用

physics OF FLUIDs 1996年第9期8卷 2441-2446页

作者： sommerer, JC M.S. Eisenhower Research Center The Johns Hopkins University Applied Physics Laboratory Laurel Maryland 20723‐6099

Fractal tracer distributions, experimentally observed in surface flows, have previously been successfully modeled as the snapshot attractors of a random dynamical system. The accompanying paper by Namenson, Antonsen, and Ott [Phys. Fluids 8, 2426 (1996)] suggests that the wave number spectra of such snapshot attractors should exhibit power law dependence on wave number, where the power is given in terms of the correlation dimension of the fractal spatial pattern. Their theoretical and numerical results, while supporting the power-law result, also caution that the power law may be obscured in an experimental situation. This paper demonstrates that, with proper averaging, the predicted power-law scaling can be observed in a real experiment. (C) 1996 American Institute of physics.

关键词： DYNAmICAL sYsTEms CHAOTIC sYsTEms POWER sPECTRA INCOmPREssIBLE FLOW TRACER TECHNIQUEs FRACTALs sCALING LAWs ADVECTION

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：