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Effective permittivity and permeability of one-dimensional dielectric photonic crystal within a band gap

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Chinese physics B 2008年第7期17卷 2544-2552页

作者：郭继勇陈鸿李宏强张冶文 Pohl institute of solid state physics Tongji University

We take a finite dielectric photonic crystal as a homogeneous slab and have extracted the effective parameters. Our systematic study shows that the effective permittivity or permeability of dielectric photonic crystal is negative within a band gap region. This means that the band gap might act as ε-negative materials （ENMs） with ε 〈 0 and μ 〉 0, or μ-negative materials （MNMs） with ε 〉 0 and μ 〈 0. Moreover the effective parameters sensitively rely on size, surface termination, symmetry, etc. The effective parameters can be used to design full transmission tunnelling modes and amplify evanescent wave. Several cases are studied and the results show that dielectric photonic band gap can indeed mimic a single negative material （ENM or MNM） under some restrictions.

关键词： photonic crystal negative permittivity negative permeability

Simulation of water potential for the electronic structure of serine

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Chinese physics B 2009年第5期18卷 1968-1978页

作者：王兴荣郑浩平 Pohl institute of solid state physics Tongji University

First-principles, all-electron, ab initio calculations have been performed to construct an equivalent water potential for the electronic structure of serine （Ser） in solution. The calculation is composed of three steps. The first step is to search for the configuration of the Ser _ nH2O system with a minimum energy. The second step is to calculate the electronic structure of Ser with the water molecule potential via the self-consistent cluster-embedding method （SCCE）, based on the result obtained in the first step. The last step is to calculate the electronic structure of Set with the dipole potential after replacing the water molecules with dipoles. The results show that the occupied states of Ser are raised by about 0.017 Ry on average due to the effect of water. The water effect can be successfully simulated by using the dipole potential. The obtained equivalent potential can be applied directly to the electronic structure calculation of protein in solution by using the SCCE method.

关键词： serine electronic structure water self-consistent cluster-embedding calculation

Design and Analysis of Microstrip Multi-Channeled Filter Using Photonic Crystal Branchy Defect

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Journal of Rare Earths 2006年第z1期24卷 136-139页

作者： Li Yunhui Jiang Haitao He Li Li Hongqiang Zhang Yewen Chen Hong Pohl institute of solid state physics Tongji University Shanghai 200092 China Pohl Institute of Solid State Physics Tongji University Shanghai 200092 China Pohl Institute of Solid State Physics Tongji University Shanghai 200092 China Pohl Institute of Solid State Physics Tongji University Shanghai 200092 China Pohl Institute of Solid State Physics Tongji University Shanghai 200092 China Pohl Institute of Solid State Physics Tongji University Shanghai 200092 China

A multi-channeled filter based on branchy defect in a microstrip photonic crystal was proposed. By introducing a branchy structure across the defect region, multiple defect modes will appear inside the photonic gap, leading to the multi-channeled filtering phenomenon. In comparison with the conventional multi-channeled filters, the proposed structure is more compact and tunable as far as the device volume and fabrication are concerned. The microwave experiment results are found in agreement with simulation results.

关键词： photonic crystals defect mode multi-channeled filter

Einstein Probe discovery of EP240408a: A peculiar X-ray transient with an intermediate timescale

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Science China(physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 222-240页

作者： Wenda Zhang Weimin Yuan Zhixing Ling Yong Chen Nanda Rea Arne Rau Zhiming Cai Huaqing Cheng Francesco Coti Zelati Lixin Dai Jingwei Hu Shumei Jia Chichuan Jin Dongyue Li Paul O’Brien Rongfeng Shen Xinwen Shu Shengli Sun Xiaojin Sun Xiaofeng Wang Lei Yang Bing Zhang Chen Zhang Shuang-Nan Zhang Yonghe Zhang Jie An David Buckley Alexis Coleiro Bertrand Cordier Liming Dou Rob Eyles-Ferris Zhou Fan Hua Feng Shaoyu Fu Johan P.U.Fynbo Lluis Galbany Saurabh W.Jha Shuaiqing Jiang Albert Kong Erik Kuulkers Weihua Lei Wenxiong Li Bifang Liu Mingjun Liu Xing Liu Yuan Liu Zhu Liu Chandreyee Maitra Alessio Marino Itumeleng Monageng Kirpal Nandra Jeremy Sanders Roberto Soria Lian Tao Junfeng Wang Song Wang Tinggui Wang Zhongxiang Wang Qingwen Wu Xuefeng Wu Dong Xu Yanjun Xu Suijian Xue Yongquan Xue Zijian Zhang Zipei Zhu Hu Zou Congying Bao Fansheng Chen Houlei Chen Tianxiang Chen Wei Chen Yehai Chen Yifan Chen Chenzhou Cui Weiwei Cui Yanfeng Dai Dongwei Fan Ju Guan Dawei Han Dongjie Hou Haibo Hu Maohai Huang Jia Huo Zhenqing Jia Bowen Jiang Ge Jin Chengkui Li Junfei Li Longhui Li Maoshun Li Wei Li Zhengda Li Tianying Lian Congzhan Liu Heyang Liu Huaqiu Liu Fangjun Lu Laidan Luo Jia Ma Xuan Mao Haiwu Pan Xin Pan Liming Song Hui Sun Yunyin Tan Qingjun Tang Yihan Tao Hao Wang Juan Wang Lei Wang Wenxin Wang Yilong Wang Yusa Wang Qinyu Wu Haitao Xu Jingjing Xu Xinpeng Xu Yunfei Xu Zhao Xu Changbin Xue Yulong Xue Ailiang Yan Haonan Yang Xiongtao Yang Yanji Yang Juan Zhang Mo Zhang Wenjie Zhang Zhen Zhang Zhen Zhang Ziliang Zhang Donghua Zhao Haisheng Zhao Xiaofan Zhao Zijian Zhao Hongyan Zhou Yilin Zhou Yuxuan Zhu Zhencai Zhu National Astronomical Observatories Chinese Academy of Sciences School of Astronomy and Space Sciences University of Chinese Academy of Sciences Key Laboratory of Particle Astrophysics institute of High Energy physics Chinese Academy of Sciences institute of Space Sciences (ICE) CSIC Institut d’Estudis Espacials de Catalunya (IEEC) Max Planck institute for Extraterrestrial physics Innovation Academy for Microsatellites Chinese Academy of Sciences Department of physics University of Hong Kong School of physics and Astronomy University of Leicester School of physics and Astronomy Sun Yat-sen University Department of physics Anhui Normal University Shanghai institute of Technical physics Chinese Academy of Sciences physics Department Tsinghua University Nevada Center for Astrophysics University of Nevada Las Vegas Department of physics and Astronomy University of Nevada Las Vegas South African Astronomical Observatory Department of Astronomy University of Cape Town Department of physics University of the Free state Université Paris Cité CNRS Astroparticule et Cosmologie Université Paris Cité CEA Paris-Saclay IRFU/DAp-AIM Department of Astronomy Guangzhou University Cosmic Dawn Center (DAWN) Niels Bohr institute University of Copenhagen Department of physics and Astronomy Rutgers the state University of New Jersey institute for Cosmic Ray Research The University of Tokyo ESA/ESTEC Department of Astronomy School of physics Huazhong University of Science and Technology INAF-Osservatorio Astrofisico di Torino Sydney institute for Astronomy School of physics The University of Sydney Department of Astronomy Xiamen University institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Department of Astronomy University of Science and Technology School of Astronomy and Space Sciences University of Science and Technology of China institute of Deep Space Sciences Deep Space Exploration Laboratory Department of Astronomy School of physics and Astronomy Yunnan University Shanghai Astronomical Observatory Chi

We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe （EP） and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength *** new transient was first detected with Wide-field X-ray Telescope （WXT） on board EP on April 8th,2024,manifested in an intense yet brief X-ray flare lasting for *** flare reached a peak flux of 3.9×10-9erg cm-2s-1in 0.5-4 ke V,～300 times brighter than the underlying X-ray emission detected throughout the *** and more precise follow-up observations by EP/FXT,Swift and NICER confirmed the finding of this new *** X-ray spectrum is non-thermal in 0.5-10 ke V,with a power-law photon index varying *** X-ray light curve shows a plateau lasting for ～4 d,followed by a steep decay till becoming undetectable ～10 d after the initial *** on its temporal property and constraints from previous EP observations,an unusual timescale in the range of 7-23 d is found for EP240408a,which is intermediate between the commonly found fast and long-term *** counterparts have been found in optical and near-infrared,with the earliest observation at 17 h after the initial X-ray detection,suggestive of intrinsically weak emission in these *** demonstrate that the remarkable properties of EP240408a are inconsistent with any of the transient types known so far,by comparison with,in particular,jetted tidal disruption events,gamma-ray bursts,X-ray binaries and fast blue optical *** nature of EP240408a thus remains an *** suggest that EP240408a may represent a new type of transients with intermediate timescales of the order of～10 *** detection and follow-ups of more of such objects are essential for revealing their origin.

关键词： X-ray transients ${\bm~{Einstein~~Probe}}$

Influence of Dzyaloshinskii-Moriya and Kaplan-Shekhtman-Entinwohlman-Aharony superexchange interactions on ground state properties of the one-dimensional spin-Peilers model in open chain

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Chinese physics B 2010年第11期19卷 637-640页

作者：刘海莲黄仙山王治国石云龙 School of Mathematics and physics Anhui University of Technology institute of solid state physics Shanxi Datong University Pohl institute of solid state physics Tongji University

The effects of the Dzyaloshinskii Moriya （DM） and the Kaplan-Shekhtman-Entinwohlman-Aharony （KSEA） superexchange interactions on the ground state properties of the one-dimensional spin-Peilers system in open chain are studied by using the Lanczos numerical method. The study concentrates mainly on the influence of systemic dimerisation in open chain. The results show that systemic ground state energy density varies with dimerisation parameter 5 in different DM interactions, and there exists a special point 5c where the DM interaction has no influence on the systemic dimerisation, no matter whether the DM interaction is relative or irrelative to systemic dimerisation （η= 1 or η=0）. The KSEA interaction has no fixed special point, but the points of intersection are dense relatively in a certain numberical value range, and sparse in other numberical value ranges. So we can conclude that the antisymmetric anisotropy DM interaction differs from the symmetric anisotropy KSEA interaction, but they are analogous in the sense of the influence of systemic dimerisation in open chain.

关键词： dimerisation Dzyaloshinskii-Moriya interaction Kaplan-Shekhtman-Entinwohlman Aharony interaction open chain

Effects of nanosized metallic palladium loading and calcination on characteristics of composite silica

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中国有色金属学会会刊：英文版 2003年第6期13卷 1394-1400页

作者：吴玉程吴侠李广海张立德 Faculty of Materials science and Engineering institute of solid state physics

In order to investigate the effects of nanosized metallic palladium loading and calcination on the characteristics of composite silica, the silica was prepared by sol-gel technique, leading to an amorphous solid with mesoporosity, and the pore size distribution is narrow, centered at 35 nm. The composite silica was formed by impregnating palladium precursor into the porous network with sequel calcination in hydrogen. The results show that the nanosized palladium as guest phase in the composite silica is subjected to the mesoporous structure and calcination, resulting in the changes of optical adsorption that red-shifted to higher wavelength with the palladium loading and the heating temperature. The tailoring of the optical properties can be ascribed to the effect of the nanosized metal particles and interactions occurred between palladium and silica.

关键词：二氧化硅钯纳米材料复合材料煅烧加载

Spin-dependent thermoelectric transport through double quantum dots

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Chinese physics B 2012年第11期21卷 432-440页

作者：王强解海卿焦虎军李志坚聂一行 institute of Theoretical physics and Department of physics Shanxi University institute of solid state physics Shanxi Datong University

We study the thermoelectric transport through a double-quantum-dot system with spin-dependent interdot cou- pling and ferromagnetic electrodes by means of the non-equilibrium Green＇s function in the linear response regime. It is found that the thermoelectric coefficients are strongly dependent on the splitting of the interdot coupling, the relative magnetic configurations, and the spin polarization of leads. In particular, the thermoelectric efficiency can reach a considerable value in the parallel configuration when the effective interdot coupling and the tunnel coupling between the quantum dots and the leads for the spin-down electrons are small. Moreover, the thermoelectric efficiency increases with the intradot Coulomb interaction increasing and can reach very high values at appropriate temperatures. In the presence of the magnetic field, the spin accumulation in the leads strongly suppresses the thermoelectric efficiency, and a pure spin thermopower can be obtained.

关键词： thermoelectric effect double quantum dots spin effect

Electronic transport through a periodic array of quantum-dot rings

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Chinese physics B 2010年第4期19卷 381-387页

作者：薛海斌张瀚尹聂一行李志坚梁九卿 institute of Theoretical physics and Department of physics Shanxi University institute of solid state physics Shanxi Datong University

Using the tight-binding approximation and the transfer matrix method, this paper studies the electronic transport properties through a periodic array of quantum-dot （QD） rings threaded by a magnetic flux. It demonstrates that the even^odd parity of the QD number in a single ring and the number of the QD rings in the array play a crucial role in the electron transmission. For a single QD ring, the resonance and antiresonance transmission depend not only on the applied magnetic flux but also on the difference between the number of QDs on the two arms of the ring. For an array of QD rings, the transmission properties are related not only to the even-odd parity of the number No of QDs in the single ring but also to the even-odd parity of the ring number N in the array. When the incident electron energy is aligned with the site energy, for the array of N rings with No = odd the antiresonance transmission cannot occur but the resonance transmission may occur and the transmission spectrum has N resonance peaks （N - 1 resonance peaks） in a period for N = odd （for N = even）. For the array of N rings with No = even the transmission properties depend on the flux threading the ring and the QD number on one arm of the ring. These results may be helpful in designing QD devices.

关键词： quantum dots electronic transport antiresonance transmission resonance transmission

Surface Growth Kinetics and Directed Percolation in a Ballistic Deposition-Reaction Model

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Chinese physics Letters 1996年第6期13卷 451-454页

作者： WANG Wei National Laboratory of solid state Microstructure Institute of Solid State Physicsand Department of PhysicsNanjing UniversityNanjing 210093 Center of Advanced Science and Technology in solid state physics Nanjing 210093

The surface growth kinetics and directed percolation processes in a(2+1)-dimensional ballistic deposition-reaction model are studied in this *** the probability P increases a transition of the morphologic structure is... 详细信息

关键词： particles. Kinetics directed