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A first-principles study of dihydroazulene as a possible optical molecular switch

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Science china(physics,Mechanics & Astronomy) 2011年第3期Mechanics & Astronomy) .卷 437-441页

作者： XIA CaiJuan1, LIU DeSheng2.3 & LIU HanChen1 1 School of Science, Xi’an Polytechnic university, Xi’an 710048, china 2.School of {2., State Key Laboratory of Crystal Materials, Shandong university, Jinan 2.0100, china 3 department of {2., Jining university, Qufu 2.3155, china 1. School of Science Xi’an Polytechnic University Xi’an 710048 China2. School of Physics State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China3. Department of Physics Jining University Qufu 273155 China

By applying nonequilibrium Green's function formalism combined with first-principles density functional theory, we investigate the electronic transport properties of the dihydroazulene optical molecular switch. Three kinds of adsorption sites including the hollow, bridge and top sites are studied. The two forms of this molecule, namely the open form and the closed form, can reversibly switch from each other upon photoexcitation. Their transmission spectra are remarkably distinctive. Theoretical results show that the current of the closed form is always significantly larger than that of the open form for all three adsorption sites, which promises this system as possibly one of the good candidates for optical switches due to its unique advantage, and which may have some potential applications in the future molecular circuit.

关键词： molecular switch nonequilibrium Green’s function electronic transport density functional theory

Exact eigenstates for a class of models describing multiphoton processes in the presence of seven bosonic modes

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Science china(physics,Mechanics & Astronomy) 2004年第6期47卷 649-657页

作者： ZHAN Zhiming1,LI Weibin2.YOU Jun2.XIE Xiaotao2.& yang Wenxing2.1.State Key Laboratory of Laser Technology,Huazhong {2. of Science and Technology,Wuhan 430074,china 2.department of physics,Huazhong {2. of Science and Technology,Wuhan 430074,china 1. State Key Laboratory of Laser Technology Huazhong University of Science and Technology 430074 Wuhan China 2. department of physics Huazhong University of Science and Technology 430074 Wuhan China

We present the analytical expressions of eigenstates and eigenenergies by using a parameter λ without the assumption of Bethe anzatz for three kinds of seven-bosonic-mode mixing models. The parameter is shown to be determined by the roots of a simple polynomial. We also demonstrate the exact analytical expressions of eigenstates and energies without any unknown parameter.

关键词： spectra, eigenstate, eigenvalue.

Heat transfer in high density electronics packaging

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Journal of Central South university of Technology 2001年第4期8卷 278-282页

作者： ZHOU Jie min 1, yang Ying 1, DENG Sheng xiang 1, YI Zheng ming 1, WANG Xi tao 2. CHEN Liu 2. Johan Liu 2.(1.department of Applied {2. and Heat Engineering, Central South university, Changsha 410083, china 2.department of Production En 1. department of Applied physics and Heat Engineering Central South University 410083 Changsha China 2. department of Production Engineering Chalmers University of Technology SE-41296 G?teborg Sweden

In order to get an insight into the thermal characteristic and to evaluate the thermal reliability of the "System in Packaging"(SIP), a new solution of electronics packaging, a heat transfer model of SIP was developed to predict the heat dissipation capacity and to investigate the effect of different factors on the tempe rature distribution in the electronics. The affecting parameters under consideration include the thermophysical properties of the substrates, the coefficient of convection heat transfer, the thickness of the chip, and the density of power dissipation. ALGOR, a kind of finite element analysis software,was used to do the model simulation. Based on the simulation and analysis of the heat conduction and convection resistance, criteria for the thermal design were established and possible measurement for enhancing power dissipation was provided. The results show that the heat transfer model provides a new and effective way to the thermal design and thermal analysis of SIP and to the mechanical analysis for the further investigation of SIP.

关键词： electronics packaging thermal reliability heat transfer

The formation and stability of Si_(1-x)C_x alloys in Si implanted with carbon ions

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Chinese Science Bulletin 2001年第3期46卷 200-204页

作者： WANG Yinshu, LI jinmin, JIN Yunfan, WANG Yutian, SUN Guosheng & LIN Lanying1. department of {2., Beijing Normal university, Beijing 100875, china 2. Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, china 3. Institute of Modern {2., Chinese Academy of Sciences, Lanzhou 730000, china department of physics Beijing Normal University Beijing China Institute of Semiconductors Chinese Academy of Sciences Beijing China Institute of Modern physics Chinese Academy of Sciences Lanzhou China

Si1-xCx alloys of carbon (C) concentration between 0.6%-1.0% were grown in Si by ion implantation and high temperature annealing. The formation of Si1-xCx alloys under different ion doses and their stability during annealing were studied. If the implanted dose was less than that for amorphizing Si crystals, the implanted C atoms would like to combine with defects produced during implantation and it was difficult to form Si1-xCx alloys after being annealed at 850℃. With the increment of implanted C ion doses, the lattice damage increased and it was easier to form Si1-xCx alloys. But the lattice strain would become saturate and only part of implanted carbon atoms would occupy the substitutional positions to form Si1-xCx alloys as the implanted carbon dose increased to a certain degree. Once Si1-xCx alloys were formed, they were stable at 950℃, but part of their strain would release as the annealing temperature increased to 1 000℃. Stability of the alloys became worse with the increment of carbon

关键词： ion implantation Si1-xCx alloys stability of Si1-xCx alloys.

On SS-quasinormal subgroups and the structure of finite groups

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Science china Mathematics 2011年第3期54卷 449-456页

作者： WEI XianBiao1,2.& GUO XiuYun2. 1department of Mathematics and physics, Anhui Institute of Architecture and Industry, Hefei 2.002., {2. 2.0} of Mathematics, Shanghai university, Shanghai 2.0444, {2. 1. department of Mathematics and physics Anhui Institute of Architecture and Industry Hefei 230022 China2. Department of Mathematics Shanghai University Shanghai 200444 China

A subgroup H of a finite group G is said to be an SS-quasinormal subgroup of G if there is a subgroup B of G such that G = HB and H permutes with every Sylow subgroup of B. In this paper, we investigate the structure of a group under the assumption that every subgroup with order pm of a Sylow p-subgroup P of G is SS-quasinormal in G for a fixed positive integer m. Some interesting results related to the p-nilpotency and supersolvability of a finite group are obtained. For example, we prove that G is p-nilpotent if there is a subgroup D of P with 1 2.D| whenever p = 2.and |D| = 2.is SS-quasinormal in G, where p is the smallest prime dividing the order of G and P is a Sylow p-subgroup of G.

关键词： S-quasinormal subgroups SS-quasinormal subgroups p-nilpotent groups supersolvable groups

The size effect on transport properties of colossal magnetoresistance materials La_(0.67)Ca_(0.33)MnO_3

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Science china(physics,Mechanics & Astronomy) 2008年第3期51卷 251-257页

作者： LI PeiGang1,2.LEI Ming1,2.GUO YanFeng2.GUO Xi2.CHEN LeiMing2. TANG WeiHua1,2.SONG PengYun3 & CHEN JinPing3 1 department of physics,Center for Optoelectronics Materials and Devices,Zhejiang Sci-Tech {2.,Hangzhou 310018,china 2.National Laboratory for Condensed Matter physics,Institute of physics,Chinese Academy of Sciences,Beijing 100080,china 3 department of physics,Peking {2.,Beijing 100875,china 1. department of physics Center for Optoelectronics Materials and Devices Zhejiang Sci-Tech University Hangzhou 310018 China 2. National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China 3. department of physics Peking University Beijing 100875 China

High quality La0.67Ca0.33MnO3 (LCMO) film was deposited via a novel pulsed electron deposition technique on SrTiO3(100) single crystal substrate. The micro-bridge with different widths was fabricated by using electron beam lithography (EBL) technique and their transport properties were studied. For the micro-bridges with width of 2.and 1.5 μm,the insulator-to-metal transition temperature (TP) keeps un-changed compared with the film. For the micro-bridges with width of 1 μm,the TP shifts towards the lower temperature by 50 K. When the width decreases down to 500 nm,the insulator-to-metal transition disappears. The magnetoresistance be-havior of these micro-bridges was studied,and the results show that the low field magnetoresistance (LFMR) decreases and the high field magnetoresistances (HFMR) keep almost unchanged as the width of micro-bridge is reduced.

关键词： colossal magnetoresistance pulsed electron deposition electron beam lithography electrical transport properties

Two mode photon bunching effect as witness of quantum criticality in circuit QED

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Science china(physics,Mechanics & Astronomy) 2009年第12期52卷 1898-1905页

作者： AI Qing1,WANG YingDan2.LONG GuiLu1,3 & SUN ChangPu4 1 department of physics,Tsinghua {2.,Beijing 100084,china 2.department of physics,{2. of Basel,Klingelbergstrasse 82.4056 Basel,Switzerland 3 Tsinghua National Laboratory for Information Science and Technology,Beijing 100084,china 4 Institute of Theoretical physics,Chinese Academy of Sciences,Beijing 100080,china 1. department of physics Tsinghua University Beijing 100084 China 2. department of physics University of Basel Klingelbergstrasse 82 4056 Basel Switzerland 3. Tsinghua National Laboratory for Information Science and Technology Beijing 100084 China 4. Institute of Theoretical physics Chinese Academy of Sciences Beijing 100080 China

We suggest a scheme to probe critical phenomena at a quantum phase transition (QPT) using the quantum correlation of two photonic modes simultaneously coupled to a critical system. As an experimentally accessible physical implementation,a circuit QED system is formed by a capacitively coupled Josephson junction qubit array interacting with one superconducting transmission line resonator (TLR). It realizes an Ising chain in the transverse field (ICTF) which interacts with the two magnetic modes propagating in the TLR. We demonstrate that in the vicinity of criticality the originally independent fields tend to display photon bunching effects due to their interaction with the ICTF. Thus,the occurrence of the QPT is reflected by the quantum characteristics of the photonic fields.

关键词： quantum phase transition photon bunching circuit QED

Effect of Dy on Structure and Magnetic Properties of Dy_xFe_(60.5-x)Pt_(39.5) Alloys

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Journal of Wuhan university of Technology(Materials Science) 2010年第1期25卷 135-137页

作者：左卫群 department of Information of Materials Science and Engineering Guilin University of Electronic Technology

Effects of the content of Dy on structure and magnetic properties of DyxFe60.5-xPt39.5 alloys（x = 0, 0.5, 1.0, 1.5） were investigated. The results of XRD analysis proved that the phase-transitional temperature of DyxFe60.5-xPt39.5 alloys from disordered face-centered-cubic structure to ordered face-centered-tetragonal cubic structure decreases with the increase of the content of Dy（x）. Suitable content of Dy can improve the exchange coupling between soft magnetic phase and hard magnetic phase by refining grain size, while the remanence ratio and coercivity of the Fe60.5Pt39.5 alloy can be significantly improved by a small replacement of Fe by Dy, good magnetic properties were obtained in Dy0.5Fe60.0Pt39.5 alloys.

关键词： phase transformation degree of order grain size exchange coupling

Weak martingale Hardy spaces and weak atomic decompositions

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Science china Mathematics 2006年第7期49卷 912-921页

作者： HOU Youliang & REN Yanbo School of Mathematics and Statistics, Wuhan university, Wuhan 430072. china {2. of Mathematics & physics, henan university of Science and Technology, Luoyang 471003, china 1. School of Mathematics and Statistics Wuhan University Wuhan 430072 China 2. department of Mathematics & physics Henan University of Science and Technology Luoyang 471003 China

In this paper we define some weak martingale Hardy spaces and three kinds of weak atoms. They are the counterparts of martingale Hardy spaces and atoms in the classical martingale Hp-theory. And then three atomic decomposition theorems for martingales in weak martingale Hardy spaces are proved. With the help of the weak atomic decompositions of martingale, a sufficient condition for a sublinear operator defined on the weak martingale Hardy spaces to be bounded is given. Using the sufficient condition, we obtain a series of martingale inequalities with respect to the weak Lp-norm, the inequalities of weak (p ,p)-type and some continuous imbedding relationships between various weak martingale Hardy spaces. These inequalities are the weak versions of the basic inequalities in the classical martingale Hp-theory.

关键词： martingale, weak Hardy space, weak atom, atomic decomposition.