检索结果-南通市图书馆

Direct visualization of laser-driven dynamic fragmentation in tin by in situ x-ray diffraction

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Matter and Radiation at Extremes 2024年第5期9卷 109-114页

作者： Jing Yang Xinxin Wang Liang Xu Qiannan Wang Yi Sun Jiangtao Li Lin Zhang Yinghua Li Yuying Yu Pei Wang Qiang Wu Jianbo Hu laboratory for Shock Wave and Detonation physics Institute of Fluid PhysicsChina Academy of Engineering PhysicsMianyang 621900China laboratory of Computational physics Institute of Applied Physics and Computational MathematicsBeijing 100094China

We present a novel method for investigating laser-driven dynamic fragmentation in tin using in situ X-ray *** experimental results demonstrate the feasibility of the method for simultaneously identifying the phase and temperature of fragments through analysis of the diffraction ***,we observe a deviation from the widely accepted isentropic release assumption,with the temperature of the fragments being found to be more than 100 K higher than expected,owing to the release of plastic work during dynamic *** findings are further verified through extensive large-scale molecular dynamics simulations,in which strain energies are found to be transferred into thermal energies during the nucleation and growth of voids,leading to an increase in *** findings thus provide crucial insights into the impact-driven dynamic fragmentation phenomenon and reveal the significant influence of plastic work on material response during shock release.

关键词： dynamic release diffraction

Recent advances in protein conformation sampling by combining machine learning with molecular simulation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese physics B 2024年第3期33卷 80-87页

作者：唐一鸣杨中元姚逸飞周运谈圆王子超潘瞳熊瑞孙俊力韦广红 Department of physics State Key Laboratory of Surface Physicsand Key Laboratory for Computational Physical Sciences (Ministry of Education)Shanghai 200438China

The rapid advancement and broad application of machine learning(ML)have driven a groundbreaking revolution in computational *** of the most cutting-edge and important applications of ML is its integration with molecular simulations to improve the sampling efficiency of the vast conformational space of large *** review focuses on recent studies that utilize ML-based techniques in the exploration of protein conformational *** first highlight the recent development of ML-aided enhanced sampling methods,including heuristic algorithms and neural networks that are designed to refine the selection of reaction coordinates for the construction of bias potential,or facilitate the exploration of the unsampled region of the energy ***,we review the development of autoencoder based methods that combine molecular simulations and deep learning to expand the search for protein ***,we discuss the cutting-edge methodologies for the one-shot generation of protein conformations with precise Boltzmann ***,this review demonstrates the promising potential of machine learning in revolutionizing our insight into the complex conformational ensembles of proteins.

关键词： machine learning molecular simulation protein conformational space enhanced sampling

维普期刊数据库

A polarized^(3)He system based on metastability-exchange optical pumping

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2024年第7期67卷 72-81页

作者： Yuting Wang Liangyong Wu Kaiyuan Zhang Mei Peng Siyu Chen Haiyang Yan State Key laboratory of Nuclear physics and Technology School of PhysicsPeking UniversityBeijing 100871China Institute of Nuclear physics and Chemistry China Academy of Engineering PhysicsMianyang 621900China Key laboratory of Nuclear physics and Ion-beam Application(MOE) Fudan UniversityShanghai 200433China Key laboratory of Neutron physics Institute of Nuclear Physics and ChemistryChina Academy of Engineering PhysicsMianyang 621900China

Hyperpolarized^(3)He nuclei have emerged as a significantly important approach in quantum precision measurement techniques,with extensive applications in fundamental physics,magnetometry,metrology,and *** this study,we report on the design and implementation of a^(3)He polarization system at the China Mianyang Research Reactor(CMRR),utilizing the metastabilityexchange optical pumping(MEOP)*** employed a Merritt coil system consisting of four square coils to furnish a uniform holding *** deployed a 2 W fiber laser to pump the metastable^(3)He atoms and conducted free induction decay(FID)detection of the polarized^(3)He nuclei using both pickup coil and optical *** the optical method,we used a50 m W linearly polarized distributed Bragg reflector(DBR)laser as the *** applied transverse light absorption polarimetry to measure the absolute nuclear polarization of the ground-state^(3)*** have developed cell fabrication capabilities at the CMRR,and cells at various pressures ranging from 100 to 1000 Pa have been fabricated and *** a typical borosilicate cell with 100 Pa pressure,the absolute polarization is measured as Pn≈70%,and the transverse relaxation time is estimated as T2≈0.5 ***,we constructed a few aluminosilicate cells,each carefully filled with pure^(3)He at a pressure of 100 ***,we conducted a comprehensive evaluation of their performance in the context of MEOP.

关键词： metastability exchange optical pumping polarized^(3)He magnetic resonance

维普期刊数据库

Facile synthesis of samarium and cerium doped double perovskite cobaltite with enhanced dielectric response

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第7期42卷 1317-1327,I0005页

作者： Yasir Abbas M.Kamran M.Anis-ur-Rehman Applied Thermal physics laboratory Department of PhysicsCOMSATS University IslamabadIslamabad 45550Pakistan

The investigation of Sm-Ce doping on structure,conduction,and dielectric response of Bi_(2)Ca_(2-2x)Sm_(x)CexCoO_(6)(x=0.000,0.025,0.050,0.075)(BCSCCO)are *** the specimens were synthesized by a facile synthesis technique named the co-precipitation route.X-ray diffraction(XRD)reveals that BCSCCO crystallizes into one phase with space group P21/*** crystallite size,dislocation density,lattice parameters,lattice strain,unit cell volume,and bulk density were determined using XRD *** structural properties of Bi_(2)Ca_(2)CoO_(6)were examined using calculations based on the density functional *** and experimental values discrepancy is less than 1%.A scanning electron microscope was used for performing a microstructural *** SEM images demonstrate the homogeneous distribution of grains with a range of sizes(0.054-0.090μm).The alternating current(ac)conductivity,dielectric permittivity,and tangent loss were also studied as a function of frequency(20 Hz-3 MHz)at different temperatures(100-500℃).All synthesized samples were examined using non-linear Debye's function to determine their spreading factor and relaxation *** specimen with the lowest crystallite size(∼23 nm)exhibits a high dielectric permittivity(∼3.80×10^(6)).The conduction mechanism was examined in the studied samples with the use of Jonscher's power *** power law indicates that the BCSCCO(x=0.000,0.025)follows correlated barrier hopping,whereas the x=0.050 and 0.075 compositions follow non-overlapping polaron *** studied specimen Bi_(2)Ca_(1.9)0Sm_(0.05)0Ce_(0.05)_(0)CoO_(6)with the highest density(∼5.65 g/cm^(3))displays a high electrical conductivity(∼46.1 S/cm).These findings correspond to those published for ceramics made from calcium cobaltite using solid-state reactions(5.0-26.0 S/cm).

关键词： Bismuth calcium samarium cerium cobaltite (BCSCCO) Spreading factor Conduction mechanism Rare earths

维普期刊数据库

Microwave-Assisted Confining Growth and Liquid Exfoliation of sp^(3)-Hybrid Carbon Nitride Nano/Micro-Crystals

在线全文

学校读者我要写书评

暂无评论

Energy & Environmental Materials 2024年第6期7卷 399-408页

作者： Chenglong Shen Qing Lou Kaikai Liu Guangsong Zheng Runwei Song Jinhao Zang Xigui Yang Xing Li Lin Dong Chongxin Shan Henan Key laboratory of Diamond Optoelectronic Materials and Devices Key Laboratory of Material PhysicsMinistry of EducationSchool of Physics and Laboratory of Zhongyuan LightZhengzhou UniversityZhengzhou 450052China

As one promising carbon-based material,sp^(3)-hybrid carbon nitride has been predicted with various novel physicochemical ***,the synthesis of sp^(3)-hybrid carbon nitride is still limited by the nanaoscale,low crystallinity,complex source,and expensive ***,we have presented a facile approach to the sp^(3)-hybrid carbon nitride nano/micro-crystals with microwave-assisted confining growth and liquid ***,the carbon nitride nano/micro-crystals can spontaneously emerge and grow in the microwave-assisted polymerization of citric acid and urea,and the liquid exfoliation can break the bulk disorder polymer to retrieve the highly crystalline carbon nitride nano/*** obtained carbon nitride nano/micro-crystals present superior blue light absorption strength and surprising photoluminescence quantum yields of 57.96%in ethanol and 18.05%in solid *** experimental characterizations and density functional theory calculations reveal that the interface-trapped localized exciton may contribute to the excellent intrinsic light emission capability of carbon nitride nano/micro-crystals and the interparticle staggered stacking will prevent the aggregation-caused-quenching ***,the carbon nitride nano/micro-crystals are demonstrated to be potentially useful as the phosphor medium in light-emitting-diode for interrupting blue light-induced eye *** work paves new light on the synthesis strategy of sp^(3)-hybrid carbon nitride materials and thus may push forward the development of multiple carbon nitride research.

关键词： confining growth density functional theory liquid exfoliation luminescence sp^(3)-hybrid carbon nitride

First-principles calculation on the electronic structures, phonon dynamics, and electrical conductivities of Pb_(10)(PO_(4))_(6O) and Pb_(9)Cu(PO_(4))_(6O) compounds

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2024年第6期173卷 218-224页

作者： L.Y.Hao E.G.Fu State Key laboratory of Nuclear physics and Technology Department of Technical PhysicsSchool of PhysicsPeking UniversityBeijing 100871China

Superconducting materials with high critical temperature have the potential to revolutionize many fields,including military,electronic communications,and power ***,scientists around the world have been tirelessly working with the ultimate goal of achieving high-temperature *** 2023,a preprint by Lee et *** South Korea claimed the discovery of ultra-high-temperature superconductivity with a critical temperature of up to 423 K in Cu-doped lead-apatite(LK-99)(arXiv:2307.12008,arXiv:2307.12037),which caused a worldwide sensation and ***,the electronic structures,phonon dynamics,and electrical conductivities of LK-99 and its parent compound lead-apatite have been calculated using first-principles *** results show that the lead-apatite compound and the LK-99 compound are insulator and half-metal *** flat band characteristic is consistent with previous *** electrical conductivity of the LK-99 compound shows two extreme points,and the electrical conductivity along the C-axis increases significantly after 400 *** phonon dispersion spectra of the compounds were investigated,demonstrating their dynamic instability.

关键词： Superconductivity LK-99 Lead-apatite First-principles calculation

Finely regulated luminescent Ag-In-Ga-S quantum dots with green-red dual emission toward white light-emitting diodes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Opto-Electronic Advances 2024年第9期7卷 54-63页

作者： Zhi Wu Leimeng Xu Jindi Wang Jizhong Song Key laboratory of Materials physics of Ministry of Education Laboratory of Zhongyuan LightSchool of PhysicsZhengzhou UniversityDaxue Road 75Zhengzhou 450052China

Ag-In-Ga-S(AIGS)quantum dots(QDs)have recently attracted great interests due to the outstanding optical properties and eco-friendly components,which are considered as an alternative replacement for toxic Pb-and Cd-based ***,enormous attention has been paid to how to narrow their broadband spectra,ignoring the application advantages of the broadband *** this work,the AIGS QDs with controllable broad green-red dual-emission are first reported,which is achieved through adjusting the size distribution of QDs by controlling the nucleation and growth of AIGS ***,the AIGS QDs exhibit broad dual-emission at green-and red-band evidenced by photoluminescence(PL)spectra,and the PL relative intensity and peak position can be finely ***,the dual-emission is the intrinsic characteristics from the difference in confinement effect of large particles and tiny particles confirmed by temperature-dependent PL ***,the AIGS QDs(the size consists of 17 nm and 3.7 nm)with 530 nm and 630 nm emission could successfully be synthesized at 220°*** combining the blue light-emitting diode(LED)chips and dual-emission AIGS QDs,the constructed white light-emitting devices(WLEDs)exhibit a continuous and broad spectrum like natural sunlight with the Commission Internationale de l’Eclairage(CIE)chromaticity coordinates of(0.33,0.31),a correlated color temperature(CCT)of 5425 K,color rendering index(CRI)of 90,and luminous efficacy of radiation(LER)of 129 lm/W,which indicates that the AIGS QDs have huge potential for lighting applications.

关键词： quantum dots Ag-In-Ga-S dual emission white light-emitting diodes

Rational design of diamond through microstructure engineering:From synthesis to applications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Carbon Energy 2024年第7期6卷 94-122页

作者： Yalun Ku Wentao Huang Xing Li Li Wan Kuikui Zhang Longbin Yan Ying Guo Shaobo Cheng Chongxin Shan Henan Key laboratory of Diamond Optoelectronic Materials and Devices Key Laboratory of Material PhysicsMinistry of EducationSchool of Physics and Laboratory of Zhongyuan LightZhengzhou UniversityZhengzhouChina Institute of Quantum Materials and physics Henan Academy of SciencesZhengzhouChina

Diamond possesses excellent thermal conductivity and tunable ***,the high-pressure,high-temperature,and chemical vapor deposition methods are the most promising strategies for the commercial-scale production of synthetic *** diamond has been extensively employed in jewelry and cutting/grinding tasks,the realization of its high-end applications through microstructure engineering has long been ***,we discuss the microstructures encountered in diamond and further concentrate on cutting-edge investigations utilizing electron microscopy techniques to illuminate the transition mechanism between graphite and diamond during the synthesis and device *** impacts of distinct microstructures on the electrical applications of diamond,especially the photoelectrical,electrical,and thermal properties,are *** recently reported elastic and plastic deformations revealed through in situ microscopy techniques are also ***,the limitations,perspectives,and corresponding solutions are proposed.

关键词： diamond in situ microscopy microstructures phase transition structure-property relationship

Ternary superhydrides for high-temperature superconductivity at low pressures

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2024年第7期11卷 12-14页

作者： Pengfei Shan Liang Ma Jinguang Cheng Beijing National laboratory for Condensed Matter physics and Institute of physics Chinese Academy of Sciences School of Physical Sciences University of Chinese Academy of Sciences Key laboratory of Materials physics Ministry of Education School of Physics and Microelectronics Zhengzhou University

The quest for room-temperature superconductivity(RTSC) has been a longstanding pursuit in physics since the discovery of superconductivity in *** to the conventional Bardeen-Cooper-Schrieffer theory, atomic metallic hydrogen holds great promise for achieving this goal due to its high Debye temperature and strong electron-phonon coupling.

关键词：