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Preparation and characterization of composites of ferroelectric and nanoscale metal particles

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Chinese Science Bulletin 1995年第23期40卷 2017-2021页

作者：周济李龙土桂治轮张孝文 Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

Recently, composites of dielectric matrices and diffused phase of metal particles. colloids or clusters are of great interest for their optical, electrical and magnetic properties and potential applicatios. Many novel physical phenomena, such as optical nonlinearity, were observed and studied in these materials. However, up to now, almost all the work on this class of materials is limited in the Systems of metal colloids in some

关键词： composites of ferroelectric nanoscale metal particles.

In Situ Investigation of the Phase Transition at the Surface of Thermoelectric PbTe with van der Waals Control

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Research 2022年第3期2022卷 247-252页

作者： Feng Cheng Ao Li Siliang Wang Yangjian Lin Pengfei Nan Shuai Wang Ningyan Cheng Yang Yue Binghui Ge Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education Institutes of Physical Science and Information TechnologyAnhui UniversityHefei 230601China

The structure of thermoelectric materials largely determines the thermoelectric characteristics.Hence,a better understanding of the details of the structural transformation process/conditions can open doors for new applications.In this study,the structural transformation of PbTe(a typical thermoelectric material)is studied at the atomic scale,and both nucleation and growth are analyzed.We found that the phase transition mainly occurs at the surface of the material,and it is mainly determined by the surface energy and the degree of freedom the atoms have.After exposure to an electron beam and high temperature,highdensity crystal-nuclei appear on the surface,which continue to grow into large particles.The particle formation is consistent with the known oriented-attachment growth mode.In addition,the geometric structure changes during the transformation process.The growth of nanoparticles.is largely determined by the van der Waals force,due to which adjacent particles.gradually move closer.During this movement,as the relative position of the particles.changes,the direction of the interaction force changes too,which causes the particles.to rotate by a certain angle.

关键词： particles. PbTe Transition

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奇异金属中的超导性

Science Bulletin 2023年第9期68卷 851-853页

作者：吴颉 Ivan Bozovic Key Laboratory for Quantum Materials of Zhejiang Province School of ScienceWestlake UniversityHangzhou 310024China Brookhaven National Laboratory Upton NY 11973-5000USA Department of Chemistry Yale UniversityNew Haven CT 06520USA

In a gas of charged particles.with the density n,mass m,and charge e,the electrical conductivityσis given by the Drude formula:σ=ne^(2)/mΓ,whereΓis the scattering rate.Standard metals are well described by Landau... 详细信息

关键词： particles. 超导性 Fermi

重离子碰撞中矢量介子的整体自旋排列及其强相互作用场解释

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Science Bulletin 2023年第9期68卷 874-877页

作者：陈金辉梁作堂马余刚王群 Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China Key Laboratory of Particle Physics and Particle Irradiation(MOE) Institute of Frontier and Interdisciplinary ScienceShandong UniversityQingdao 266237China Peng Huanwu Center for Fundamental Theory and Department of Modern Physics University of Science and Technology of ChinaHefei 230026China

particles.and fields are two fundamental forms of matter in our natural world.particles.are excitations or quanta of their corresponding fields,which are characterized by quantum numbers such as mass,charge,spin,and parity.Photons,for example,are quanta of electromagnetic fields that mediate electromagnetic forces among charged particles.

关键词： particles. 重离子碰撞矢量介子

Off-axis optical levitation and transverse spinning of metallic microparticles

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Photonics Research 2021年第11期9卷 2144-2151页

作者： YANSHENG LIANG SHAOHUI YAN ZHAOJUN WANG BAOLI YAO MING LEI MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter Shaanxi Province Key Laboratory of Quantum Information and Quantum Optoelectronic DevicesSchool of PhysicsXi’an Jiaotong UniversityXi’an 710049China State Key Laboratory of Transient Optics and Photonics Xi'an Institute of Optics and Precision MechanicsChinese Academy of SciencesXi'an 710119China

Optical manipulation of metallic microparticles.remains a significant challenge because of the strong scattering forces arising from the high extinction coefficient of the particles.This paper reports a new mechanism for stable confinement of metallic microparticles.using a tightly focused linearly polarized Gaussian beam.Theoretical and experimental results demonstrate that metallic microparticles.can be captured off the optical axis in such a beam.Meanwhile,the three-dimensionally confined particles.are observed spinning transversely as a response to the asymmetric force field.The off-axis levitation and transverse spinning of metallic microparticles.may provide a new way for effective manipulation of metallic microparticles.

关键词： particles. field. metallic

Experimental and Simulation Study on Shielding Performance of Developed Hydrogenous Composites

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Space(Science & Technology) 2022年第1期2022卷 16-26页

作者： Minghui Cai Tao Yang Hongwei Li Haixia Yang Jianwei Han National Space Science Center Chinese Academy of SciencesBeijing 100190China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China Institute of Chemistry Chinese Academy of SciencesBeijing 100190China

Space radiation has been well-known as the main health hazard to crews involved in manned space explorations.Two kinds of hydrogenous-rich composites are developed through compressing molding under high-temperature processing techniques for shielding space radiation.Beams of 80~400 MeV/n ^(12)C of the Heavy Ion Research Facility in Lanzhou are used to test the shielding properties of the new composites.Experimental results show that the composite with more hydrogen content has higher shielding ability for 80 and 400 MeV/n ^(12)C particles.Meanwhile,the addition of boron has no obvious effect on improving the shielding performance of the composite.Monte Carlo radiation transport codes were used to assess the shielding performance of composite in real space radiation.The simulation results show that hydrogenous-rich composite has significant advantage in space radiation shielding compared with traditional aluminum.

关键词： composite particles. composites

A New Estimate for the Dispersion Velocity of Galactic Dark Matter particles

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Chinese Physics Letters 1998年第8期15卷 617-619页

作者：朱宗宏吴江华张元仲 Institute of Theoretical Physics Chinese Academy of SciencesBeijing 100080 Department of Astronomy Beijing Normal UniversityBeijing 100875

An independent method is proposed to estimate the dispersion velocity of galactic dark matter particles.This method is based on the observed quasar-galaxy association samples that are caused by gravitational lensing.All resulting dispersion velocities are much higher than-220km·s^(-1),a value expected from the virial theorem,which shows that the conventional assumption of virialization may be invalid in the halo regions of galaxies.

关键词： particles. dispersion Dispersion

Tunneling Time of particles.Through a Potential Barrier

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Chinese Physics Letters 2000年第12期17卷 902-904页

作者：李春芳王奇 CCAST(World Laboratory) P.O.Box 8730Beijing 100080 Department of Physics Shanghai UniversityShanghai 200436(mailing address)

A new tunneling time is proposed by introducing the transfer speed of energy carried by tunneling particles. This speed is similar to the energy transfer speed in electromagnetism, and with the tunneling time, the well-known superluminality may be avoided. The low energy limit, the critical limit, and the opaque limit are considered, which are physically meaningful. Comparisons with dwell time and Biittiker and Landauer’s semiclassical time are also made.

关键词： particles. tunneling limit

Influence of the Size Distribution of particles.on the Viscous Property of an Electrorheological Fluid

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Chinese Physics Letters 1997年第2期14卷 151-154页

作者：王作维林志方陶瑞宝 T.D.Lee Physics Laboratory and Department of Physics Fudan UniversityShanghai 200433

The influence of the size distribution of particles.on the viscous property of an electrorheological fluid has been investigated by the molecular dynamic simulation method.The shear stress of the fluid is found to decrease with the increase of the variance σ^(2) of the Gaussian distribution of the particle size,and then reach a steady value whenσis larger than 0.5.This phenomenon is attributed to the influence of the particle size distribution on the dynamic structural evolution in the fluid as well as the strength of the different chain-like structures formed by the particles.

关键词： particles. method. distribution