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Dense coding scheme using superpositions of Bell-states and its NMR implementation

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Science china(Physics,Mechanics & Astronomy) 2005年第1期48卷 57-67页

作者： ZHANG Jingfu, XIE Jingyi, DENG Zhiwei & LU Zhiheng Key Laboratory for Quantum Information and Measurements, Department of Physics, Tsinghua University, beijing 100084, china Center for Quantum Information, Tsinghua University, beijing 100084, china Department of Materials Science and Engineering, beijing Normal University, beijing 100875, china Testing and Analytical Center, beijing Normal University, beijing 100875, china Department of Physics, beijing Normal University, beijing 100875, china 1. Key Laboratory for Quantum Information and Measurements Department of Physics Tsinghua University 100084 Beijing China 2. Center for Quantum Information Tsinghua University 100084 Beijing China 3. Department of Materials Science and Engineering Beijing Normal University 100875 Beijing China 4. Testing and Analytical Center Beijing Normal University 100875 Beijing China 5. Department of Physics Beijing Normal University 100875 Beijing China

Dense coding using superpositions of Bell-states is proposed. The generalized Grover's algorithm is used to prepare the initial entangled states, and the reverse process of the quantum algorithm is used to determine the entangled state in the decoding measurement. Compared with the previous schemes, the superpositions of two Bell-states are exploited. Our scheme is demonstrated using a nuclear magnetic resonance (NMR)quantum computer. The corresponding manipulations are obtained. Experimental results show a good agreement between theory and experiment. We also generalize the scheme to transmit eight messages by introducing an additional two-state system.

关键词： dense coding, superpositions of Bell-states, generalized Grover's algorithm, nuclear magnetic res-onance, quantum computer.

Full fermion-boson vertex function derived in terms of symmetry relations in Abelian gauge theory

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Science china(Physics,Mechanics & Astronomy) 2008年第9期51卷 1206-1213页

作者： HE HanXin china Institute of Atomic Energy, beijing 102413, china china Institute of Atomic Energy Beijing 102413 China

Nonperturbative studies such as confinement and dynamical chiral symmetry breaking need the nonperturbative interacting vertex functions. In this paper, an approach to determining the full fermion-boson vertex function in four-dimensional Abelian gauge theory is presented: this full vertex function is derived in terms of a set of normal (longitudinal) and transverse Ward-Takahashi relations for the fer-mion-boson (vector) and axial-vector vertices in the momentum space in the case of massless fermion. Such a derived fermion-boson vertex function should be sat-isfied both perturbatively and nonperturbatively. The fact that such a derived full fermion-boson vertex function to one-loop order holds indeed is proven and the nonperturbative form of this vertex is also under discussion.

关键词： symmetry Ward-Takahashi relations full fermion-boson vertex function

Challenges in the theoretical investigations of lipid membrane configurations

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Chinese Physics B 2013年第2期22卷 36-44页

作者：涂展春 Department of Physics Beijing Normal University Kavli Institute for Theoretical Physics china Chinese Academy of Sciences

We report some key results in the theoretical investigations of configurations of lipid membranes and present several challenges in this field,which involve（i）the exact solutions to the shape equation of lipid vesicles,（ii）the exact solutions to the governing equations of open lipid membranes,（iii）the neck condition of two-phase vesicles in the budding state,（iv） the nonlocal theory of membrane elasticity,and（v）the relationship between the symmetry and the magnitude of the free energy.

关键词： configuration lipid membrane

Calculating Models of Mass Action Concentrations for Fe-P and Cr-P Melts and Optimization of Their Thermodynamic Parameters

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International Journal of Minerals,Metallurgy and Materials 1999年第3期13卷 174-177页

作者： Jian Zhang(Metallurgy School, University of Science and Technology beijing, beijing 100083, china) Metallurgy School University of Science and Technology Beijing Beijing 100083 China

Based on the phase diagrams, reliable reference experimental data and the coexistence theory of metallic melts structure involving compound formation, calculating models of mass action concentrations for Fe-P and Cr-P melts have been formulated. At the same time, some of their thermodynamic parameters have been optimized. The calculated results not only agree well with the measuredvalues, but also obey the mass action law rigorously, this in turn shows that these models can reflect the structural characteristics of corresponding melts.

关键词： activity phase diagram coexistence theory mass action concentration

Calculating Models of Mass Action Concentrations for Ni-Mn and Co-Mn Melts and Optimization of Their Thermodynamic Parameters

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International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 246-250页

作者： Jian Zhang (Metallurgy School, University of Science and Technology beijing, beijing 100083, china) Metallurgy School University of Science and Technology Beijing Beijing 100083 China

According to phase diagrams, measured activities as well as the coexistence theory of motallic melts structure involving compound formation, the calculating models of mass action concentrations for Ni-Mn and Co-Mn melts are formulated and their thermodynamic parameters are optimized. As a result, the calculated mass action concentrations agree well with the corresponding measured activities, showing that these models can reflect the structural characteristics of both Ni-Mn and Co-Mn melts.

关键词： activity metallic melts coexistence theory mass action concentration

Dynamic information theory and information description of dynamic systems

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Science china(Physics,Mechanics & Astronomy) 2010年第4期53卷 607-627页

作者： XING XiuSan Department of Physics, beijing Institute of Technology, beijing 100081, china 1. Department of Physics Beijing Institute of Technology Beijing 100081 China

In this paper, we develop dynamic statistical information theory established by the author. Starting from the ideas that the state variable evolution equations of stochastic dynamic systems, classical and quantum nonequilibrium statistical physical systems and special electromagnetic field systems can be regarded as their information symbol evolution equations and the definitions of dynamic information and dynamic entropy, we derive the evolution equations of dynamic information and dynamic entropy that describe the evolution laws of dynamic information. These four kinds of evolution equations are of the same mathematical type. They show in unison when information transmits in coordinate space outside the systems that the time rate of change of dynamic information densities originates from their drift, diffusion and dissipation in state variable space inside the systems and coordinate space in the transmission processes, and that the time rate of change of dynamic entropy densities is caused by their drift, diffusion and production in state variable space inside the systems and coordinate space in the transmission processes. When space noise can be neglected, an information wave will appear. If we only consider the information change inside the systems, dynamic information evolution equations reduce to information equations corresponding to the dynamic equations which describe evolution laws of the above dynamic systems. This reveals that the evolution laws of respective dynamic systems can be described by information equations in a unified fashion. Hence, the evolution processes of these dynamic systems can be abstracted as the evolution processes of information. Furthermore, we present the formulas for information flow, information dissipation rate, and entropy production rate. We prove that the information production probably emerges in a dynamic system with internal attractive interaction between the elements, and derive a formula for this information production

关键词： dynamic information evolution equation informationization of dynamic equation information wave information flow and force information dissipation and production degradation and evolution

MECHANISMS AND PREDICTION OF FRACTURE TOUGHNESS ANISOTROPY OF HIGH STRENGTH Al ALLOYS

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Acta Metallurgica Sinica(English Letters) 1992年第5期5卷 324-329页

作者： LI Huanxi CHEN Changqi beijing University of Aeronautics and Astronautics,beijing,china beijing Univ of Aeronautics and Astronautics Beijing China

Contributions of weak grain boundary,cracking path deflection and grain boundary delamination to fracture toughness anisotropy of high strength Al alloys were evaluated based upon approaches of fracture mechanics in conjunction with physical cracking mechanisms. The predicted results are close to those experimentally determined in the literature and in this *** strong anisotropy of fracture toughness of high strength Al alloys is therefore attri- buted mainly to weak grain boundary cracking,cracking path deflection and grain boundary *** the methods of this work,short-transverse fracture toughness values of some semi-products can he estimated from in-plane toughness values and corresponding frac- ture characteristics when it is difficult to be determined experimentally.

关键词： Al alloy fracture toughness anisotropy

A NOTE ON THE CONSISTENCY OF LS ESTIMATES IN LINEAR MODELS

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Chinese Annals of Mathematics,Series B 2001年第4期22卷 471-474页

作者： CHEN XIRU The Graduate School at beijing, University of Science and Technology of china, beijing 100039, china. The Graduate School at beijing University of Science and Technology of China Beijing 100039 China

It is well known that when the random errors are iid. with finite variance, the week and the strong consiStency of LS estimate of multiple regression coefficients are equivalent. This note, by constructing a counter-example, shows that this equivalence no longer holds true in case that the random errors possess only the r-th moment with 1≤5 T ＜ 2.

关键词： Linear regression model Consistency LS estimate

MECHANISM FOR DIFFUSION OF BORON IN γ-Fe

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Acta Metallurgica Sinica(English Letters) 1992年第5期5卷 318-323页

作者： YU Zongsen CHEN Ning University of Science and Technology beijing,beijing,china beijing Univ of Science and Technology Beijing China

Mechanism for diffusion of B in γ-Fe is believed to be mainly by means of boron-vacancy complexes other than as interstitial atoms *** was made of calculation on the ba- sis of theoretical model proposed by the *** calculated diffusion coefficient of B in γ-Fe after this mechanism is consistent with the experimental *** addition,this is also supported by the non-equilibrium segregation phenomenon of B at grain boundaries of γ-Fe and the lattice constant measurement of Fe-B alloy.

关键词： boron vacancy diffusion non-equilibrium segregation γ-Fe