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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 {3. for Quantum Information, Tsinghua university, beijing 100084, china Department of Materials Science and Engineering, beijing normal university, beijing 100875, china testing and analytical {3., 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.

The study of two-color excitation upconversion of Pr(0.5)Yb(3.:ZBLAN

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Science china(Physics,Mechanics & Astronomy) 2006年第2期49卷 169-177页

作者： CHEN Xiaobo1 & SONG Zengfu2 1. Applied Optics beijing Area Major Laboratory, Analysis and testing center,{3., beijing 100875, china 2. Peking university, Physics School, beijing 100871, china Applied Optics beijing Area Major Laboratory Analysis testing center Beijing Normal University Beijing 100875 China Physics School Peking University Beijing 100871 China

The excited state absorption upconversion of Pr(0.5)Yb(3.:ZBLAN glass material, under two-color excitation of the 960 nm semiconductor laser and the Xe lamp light simultaneously, is reported in this article. It was found that the upconversion emission spectra of 480.1, 519.0, 601.9 and 63..8 nm coincide with the common emission spectra. Meanwhile, the upconversion-excitation spectrum has three obvious peaks under two-color excitation, and they respectively correspond to the 856.0 nm upconversion ex-citation transition [1G4(Pr3.)→1I6(Pr3.) and 1G4(Pr3.)→3.1(Pr3.)], the 789.0 nm upconver-sion excitation transition 1G4(Pr3.)→3.2(Pr3.), and the 803.7 nm upconversion excitation transition 3.6(Pr3.)→1D2(Pr3.). The upconversion excitation transition 1G4(Pr3.)→1I6(Pr3.) is strong because its oscillator strength f = 23.040×10?6 is large, which results in a large peak appearing in the upconversion excitation spectrum. That is just the new interesting two-color excitation upconversion luminescence phenomenon of Pr(0.5)Yb(3.:ZBLAN induced by one laser and one continuous normal light simultaneously.

关键词： upconversion volumetric three-dimensional display two-color excitation.

From the Green's Function in Tight-Binding Representation to Interatomic Many-body Potentials

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Journal of Materials Science & Technology 1999年第4期15卷 315-319页

作者： Shaojun LIU(Department of physics, beijing normal university, beijing 100875, china)Xiaobo WEI(Department of Physics, Liuzhou College of Education, Liuzhou 545005, china)Zhaodou CHEN Jun CAI and Benkun MA(Department of Physics, beijing normal university, beijing normal Univ Dept Phys Beijing 100875 Peoples R China Liuzhou Coll Educ Dept Phys Liuzhou 545005 Peoples R China

In this paper, we deduce the analytical form of many-body interatomic potentials based on the Green's function in tight-binding representation. The many-body potentials are expressed as the functions of the hopping integrals which are the physical origin of cohesion of atoms. For thesimple case of s-valent system, the inversion of the many-body potentials are discussed in detail by using the lattice inversion method.

关键词： Rev Li Chen From the Green’s Function in Tight-Binding Representation to Interatomic Many-body Potentials body

Mechanisms of invasive population establishment and spread of pinewood nematodes in china

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Science china(Life Sciences) 2009年第6期52卷 587-594页

作者： XIE BingYan1,CHENG XinYue2,SHI Juan3.ZHANG QingWen4,DAI ShuMing1,CHENG Fei Xue2 & LUO YouQing3.1 Institute of Vegetables and Flowers,Chinese Academy of Agricultural Sciences,beijing 100081,china 2 beijing normal university,beijing 100875,china 3.beijing Forestry university,beijing 100083.china 4 Chinese Agricultural university,beijing 100094,china 1. Institute of Vegetables and Flowers Chinese Academy of Agricultural Sciences Beijing 100081 China 2. beijing normal university Beijing 100875 China 3. beijing Forestry university Beijing 100083 China 4. Chinese Agricultural university Beijing 100094 China

This paper summarizes the results of our study of the pinewood nematode(Bursaphelenchus xylophi-lus).By population genetic analysis,it was determined that there was no genetic bottle caused by the founder effect and genetic drift in the Chinese invasive *** invasions with large amounts of nematodes from different sources led to rich genetic diversity in the invasive *** high genetic diversity in the invasive process may be one of the genetic mechanisms in its successful *** testing interspecies competition,it was shown that,with high fecundity and a strong competitive ability,*** outcompeted the native species *** in the natural ecosystem during the invasion *** displacement may be one of the ecological mechanisms of ***'s *** addition,an unequal interspecific hybridization with intro-gress was in favor of the invasive species which also accelerated the replacement of *** by *** structures,functions and evolutions of a few important genes that are closely related to the ecological adaptation of pinewood nematodes were studied to explore the molecular mechanism of its ecological ***,the resistance and resilience mechanism of the pine ecosystem invaded by pinewood nematodes was also *** results of these studies uncovered a portion of the genetic and ecological mechanisms of PWN's successful invasion and laid a foundation for further study to obtain a comprehensive interpretation of the mechanisms of the nematode *** results also provided a scientific basis for effectively controlling the occurrence and spread of pine wilt disease which is caused by *** aspects requiring further investigation are considered.

关键词： pinewood nematode bioinvasion genetic diversity ecological adaptation resistance resilience

Approach to synthesis of novel chiral 3.chloro-2(5H)- furanone and its application in asymmetric reactions

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Chinese Science Bulletin 2000年第8期45卷 711-716页

作者： HUANG Hui & CHEN Qinghua1. Department of Chemistry, Tonghua Teacher’s College, Tonghua 13.002, china 2. Department of Chemistry, beijing normal university, beijing 100875, china Department of Chemistry Tonghua Teacher’s College Tonghua China Department of Chemistry Beijing Normal University Beijing China

The synthetic method of the novel chiral synthon, 5-/-menthyloxy-3.chloro-2-(5H)-furanone 5a and its application in asymmetric reactions were investigated. 5a is easily obtained in highly optical purity, and acts as a stable acceptor of Michael addition with oxygen nucleophiles in tandem double Michael addition / internal nucieophilic substitution to offer the spiro-cyclopropane derivative containing four stereogenic centers 8, which it is difficult to obtain by routine methods. The synthetic methods for 5a and 8 are reported in detail and the new compounds are identified on the basis of their analytical data and spectroscopic data, such as UV, IR, H NMR,13.C NMR, MS and elementary analysis. The absolute configuration of the interesting spiro-cyclopropanes, spiro [1-chloro-4-(/-menthyloxy)-5-oxo-6-oxa-biscyclo[3.1.0]hexane-2,3.(4’-/-menthyloxy-5’-/-menthyloxy- butyrolactone)] 8 was established by X-ray crystallography. This result can provide important synthetic strategy in synthesis of some complex

关键词： new chiral synthon. 5-l-menthyloxy-3.chloro-2-(5H)-furanone absolute configuration spiro-cyclopropane derivative containing multiple chiral centers.

Theorems for testing Local Activity of CNN and Application to Cardiac Purkinje Equations

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International Journal of Minerals,Metallurgy and Materials 2000年第2期14卷 139-146页

作者： Lequan Min(Applied Science School, university of Science and Technology beijing, beijing 100083. {3.) Applied Science School University of Science and Technology Beijing Beijing 100083 China

The theorems for testing the local in one-port cellular neural/inear network (CNN) cells with four local state variables are presented. Using the theorems computes the bifurcation diagrams of the cardiac Purkinje fiber (CPE) equations Which describethe long-lasting action and pace-maker potentials of the Purkinje fiber of the heart. The computer simulation shows that periodic trajectories or convergent trajectories of the CPF Equations can be foun if the cormsponing cell Parameters are located in a positive domainbut nearby edge of chaos. In particular a heart with approximate normal frequency of heartbeat but non-normal electrocardiogram maysuddenly stop by slightly perturbing the parameters of the corresponding CPF Equations when the Paramders are located nearby the edge of chaos in the bifurcation diagrams. This research seems to interpret reasonbly the phenomena that patients with cardiac diseases might suddenly die without warning.

关键词： cellular neural network local activity cardiac Purkinje fiber heartbeat

A Novel Electrochemical Oxygen Sensor for Determination of Ultra-low Oxygen Contents in Molten Metal

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Journal of university of Science and Technology beijing 2001年第2期8卷 137-140页

作者： Jialin Sun, Congjin Jin, Liansheng Li, Yanruo Hong (National Laboratory on Solid Electrolytes and Metallurgical testing Techniques, university of Science and Technology beijing, beijing 100083. china) Univ Sci & Technol beijing Natl Lab Solid Electrolytes & Met Testing Tech Beijing 100083 Peoples R China

A novel electrochemical oxygen sensor has been developed by using La beta -Al2O3.as solid electrolyte and Cr+Cr2O3.as reference electrode. The sensor not only can be used as normal oxygen sensor but also as an ultra-low oxygen sensor. Especially, it is very sensitive to measure ultra-low oxygen in molten metal. For estimating the accuracy of La beta -Al2O3.oxygen sensor, two series of oxygen activities in molten iron at different oxygen contents and different temperature were measured by both La beta -Al2O3.oxygen sensor and ZrO2 oxygen sensor. The theoretical values of oxygen activities in molten iron (3.3.%C, in mass fraction) at 1723. and 1745K were also evaluated for comparing the measuring results of two sensors. At last, the error of measurement for La beta -Al2O3.oxygen sensor was discussed too.

关键词： chemical sensor oxygen sensor ultra-low oxygen sensor La beta-Al2O3 solid electrolyte

Theoretical analysis of transcranial Hall-effect stimulation based on passive cable model

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Chinese Physics B 2015年第12期24卷 373-378页

作者：袁毅李小俚 Institute of Electrical Engineering Yanshan University State Key Laboratory of Cognitive Neuroscience and Learning & IDG Mc Govern Institute for Brain Research Beijing Normal University center for Collaboration and Innovation in Brain and Learning Sciences Beijing Normal University

Transcranial Hall-effect stimulation（THS） is a new stimulation method in which an ultrasonic wave in a static magnetic field generates an electric field in an area of interest such as in the brain to modulate neuronal activities. However, the biophysical basis of simulating the neurons remains unknown. To address this problem, we perform a theoretical analysis based on a passive cable model to investigate the THS mechanism of neurons. Nerve tissues are conductive; an ultrasonic wave can move ions embedded in the tissue in a static magnetic field to generate an electric field（due to Lorentz force）.In this study, a simulation model for an ultrasonically induced electric field in a static magnetic field is derived. Then,based on the passive cable model, the analytical solution for the voltage distribution in a nerve tissue is determined. The simulation results showthat THS can generate a voltage to stimulate neurons. Because the THS method possesses a higher spatial resolution and a deeper penetration depth, it shows promise as a tool for treating or rehabilitating neuropsychiatric disorders.

关键词： Hall-effect stimulation passive cable model neurons

Evaluation of Surface Cracks Using Magnetic Flux Leakagetesting

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Journal of Materials Science & Technology 2002年第4期18卷 319-321页

作者： Luming LI, Songling HUANG, Peng ZHENG and Keren SHINUT center, Mechanical Engineering Department, Tsinghua university, beijing 100084, {3. NDT Cent. Mech. Eng. Dept. Tsinghua Univ. Beijing 100084 China

The magnetic field distribution characteristics of surface cracks with various widths are discussed based on finite element (FEM) results. The crack depth was 0.20 mm, the width range was from 0.02 to 1.00 mm. The results showed that crack width and lift-off (the distance between surface and sensor) will influence signals. Discussed in this paper is the influence of various lift-off parameters on the peak to peak values of the normal component in magnetic flux leakage testing. The effects can be applied to evaluate surface breaking cracks of different widths and depths. An idea is presented to smooth narrow, sharp crack tips using alternating current (AC) field magnetization.

关键词： Magnetic flux leakage testing (MFL) Slot width Finite element method (FKM)