检索结果-南通市图书馆

Complex variable method for plane elasticity of icosahedral quasicrystals and elliptic notch problem

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2008年第7期51卷 773-780页

作者： li lianHe1,2 & FAN TianYou1 1 department of physics, beijing Institute of Technology, beijing 100081, china 2 College of Mathematics Science, Inner Mongolia Normal university, Hohhot 010022, china department of physics Beijing Institute of Technology Beijing 100081 China College of Mathematics Science Inner Mongolia Normal University Hohhot 010022 China

The complex variable method for the plane elasticity theory of icosahedral quasicrystals is developed. Based on the general solution obtained previously, complex representations of stress and displacement components of phonon and phason fields in the quasicrystals are given. With the help of conformal transformation, an analytic solution for the elliptic notch problem of the material is presented. The solution of the Griffith crack problem can be observed as a special case of the results. The stress intensity factor and energy release rate of the crack are also obtained.

关键词： icosahedral quasicrystals plane elasticity elliptic notch complex variable method

Chemiluminescence behavior of sodium hydrogen carbonate in the potassium permanganate-hydrogen peroxide reaction

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2010年第8期53卷 1784-1792页

作者： CHEN Hui1,2,LU Chao1,li RuiBo1,GUO GuangSheng1 & liN Jin-Ming2 1State Key Laboratory of Chemical Resource Engineering beijing university of Chemical Technology,beijing 100029,china 2department of Chemistry,tsinghua university,beijing 100084,china 1. State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China2. Department of Chemistry Tsinghua University Beijing 100084 China

Chemiluminescence (CL) phenomenon of hydrogen peroxide with potassium permanganate in the presence of sodium hydrogen carbonate was *** of the surfactant on the CL system were *** surfactants could effectively increase the CL *** scavengers and organic reagents such as nitro blue tetrazolium chloride (NBT),cytochrome c,sodium azide,ascorbic acid,thiourea,tert-butanol and dimethyl sulphoxide were used to study the emitting *** emission spectrum was recorded and the results showed that the maximal emission wavelengths of NaHCO3-H2O2-KMnO4 system were 440 and 634 *** mechanism was discussed based on electron spin resonance (ESR) spectra,fluorescence spectra and UV-vis absorption *** addition of rhodamine B or uranine into this CL system enhanced the CL *** was due to part of the energy transfer from singlet oxygen and excited triplet dimers of two CO2 molecules to rhodamine B or *** CL could be induced by excited rhodamine B or uranine.

关键词： chemiluminescence potassium permanganate emitting species energy transfer

Reverse reconciliation for continuous variable quantum key distribution

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2010年第1期53卷 100-105页

作者： LU ZhiXin 1,2 , YU li 1,2 , li Kang 1,2 , liU BingCan 1,2,3 , liN JianGui 1,2 , JIAO RongZhen 1,2 & YANG BoJun 1,21 School of Science, beijing university of Posts and Telecommunications, beijing 100876, china 2 Key Laboratory of Information Photonics and Optical Communication, Ministry of Education, beijing university of Posts and Telecommunications, beijing 100876, china 3 department of Fundamental Courses, Academy of Armored Force Engineering, beijing 100072, china 1. School of Science Beijing University of Posts and Telecommunications Beijing 100876 China2. Key Laboratory of Information Photonics and Optical Communication Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China3. Department of Fundamental Courses Academy of Armored Force Engineering Beijing 100072 China

An efficient and practical post-processing technique based on reverse reconciliation for continuous variable quantum key distribution is proposed and simulated with low-density parity check (LDPC) codes. MultiLevel Coding/ MultiStage Decoding, which fully utilizes optimization technique such as vector quantization and iterative decoding and the optimal channel coding most close to the Shannon limit, was used to realize efficient reverse reconciliation algorithm. Simulation results showed that the proposed method can improve the secure key distribution rate to 2.2 kb/s and the coding efficiency to 0.89 over 20 km in single-mode optical fiber. Moreover, there still is room for much improvement.

关键词： quantum communication key distribution reverses reconciliation low-density parity check codes

Bifurcation timescales in power spectra of black hole binaries and ultraluminous X-ray sources

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2010年第S1期53卷 177-182页

作者： WANG TaiShan1 & li TiPei1,2 1 department of physics & Center for Astrophysics,tsinghua university,beijing 100084,china 2 Key Laboratory of Particle Astrophysics,Institute of High Energy physics,Chinese Academy of Sciences,beijing 100049,china tsinghua Univ Dept Phys Beijing 100084 Peoples R China tsinghua Univ Ctr Astrophys Beijing 100084 Peoples R China Chinese Acad Sci Inst High Energy Phys Key Lab Particle Astrophys Beijing 100049 Peoples R China

For black hole binaries(BHBs) and active galactic nuclei(AGNs),bifurcation timescales(BTs) Δtb exist,below which time-domain power is significantly higher than the corresponding Fourier ***-periodic oscillations(QPOs) are removed from the Fourier spectra of BHBs.A relationship between BT,black hole mass and bolometric luminosity is *** anti-correlation between BT and luminosity of Cyg X-1 is *** removing the QPOs,BTs are also obtained for two ultraluminous X-ray sources(ULXs),M82 X-1 and NGC5408 *** results support that they harbor intermediate mass black holes(IMBHs).

关键词： black hole binary ultraluminous X-ray source power spectral density data analysis

Implementation of a multiple round quantum dense coding using nuclear magnetic resonance

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2005年第6期48卷 706-715页

作者： ZHANG Jingfu1, XIE Jingyi2, WANG Chuan1, DENG Zhiwei3, LU Zhiheng4, & long guilu1,5 1. Key Laboratory For Quantum Information and Measurements of MOE, department of physics, tsinghua university, beijing 100084,china 2. department of Materials Science and Engineering, beijing Normal university, beijing 100875, china 3. Testing and Analytical Center, beijing Normal university, beijing 100875,china 4. department of physics, beijing Normal university, beijing 100875, china 5. Key Laboratory For atomic and Molecular Nanosciences, tsinghua university, beijing 100084,china 1. Key Laboratory For Quantum Information and Measurements of MOE Department of Physics Tsinghua University 100084 Beijing China 2. department of Materials science and Engineering Beijing Normal University 100875 Beijing China 3. Testing and Analytical Center Beijing Normal University 100875 Beijing China 4. department of physics Beijing Normal University 100875 Beijing China 5. Key Laboratory For Atomic and Molecular Nanosciences Tsinghua University 100084 Beijing China

A multiple round quantum dense coding scheme based on the quantum phase estimation algorithm is proposed and implemented in a three qubit nuclear magnetic resonance (NMR) quantum computer. Using an m + 1 qubit system, Bob can transmit one of 2m+1 messages to Alice, through manipulating only one qubit and exchanging it between Alice and Bob for m rounds. The information capacity is enhanced to m + 1 bits as compared to m bits in a classical scheme. The scheme has been demonstrated in NMR system, and the experimental results show a good agreement between theory and experiment.

关键词： quantum dense coding, multiple round, nuclear magnetic resorance

Suppression of Phase and Amplitude Damping Decoherence in a Three-Level Atom in A-Configuration Using Bang-Bang Controls

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical physics 2007年第7期48卷 71-74页

作者： WANG Yan-Hui liU Xiao-Shu long Gui-Lu1 Key Laboratory for Atomic and Molecular NanoSciences and department of physics,tsinghua university,beijing 100084,china2 tsinghua National Laboratory for Information Science and Technology,tsinghua university,beijing 100084,china Key Laboratory for Atomic and Molecular NanoSciences and department of physics Tsinghua University Beijing 100084 China tsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing 100084 China

In this paper,we present decoupling bang-bang operations for the suppression of general decoherence,bothamplitude and phase damping,in a three-level system in *** give a program to design a sequence ofperiodic twinbor... 详细信息

关键词： bang-bang operation general decoherence three-level system

Microstructures and characteristics of deep trap levels in ZnO varistors doped with Y_2O_3

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2009年第12期52卷 3668-3673页

作者： liU Jun 1 ,HU Jun 1 ,HE Jinliang 1 ,liN YuanHua 2 &long WangCheng 1 1State Key Laboratory of Power Systems,department of Electrical Engineering,tsinghua university,beijing 100084,china 2State Key Laboratory of New Ceramics and Fine Processing,department of Material Science and Engineering,tsinghua university, beijing 100084,china 1. State Key Laboratory of Power Systems Department of Electrical Engineering Tsinghua University Beijing 100084 China 2. State Key Laboratory of New Ceramics and Fine Processing Department of Material Science and Engineering Tsinghua University Beijing 100084 China

In this paper discussions on ZnO based varistor ceramics doped with different ratios of Y2O3 are *** on the phase and microstructures of the samples indicates that an additional phase is detected in the samples doped with Y2O3,and the average grain size of the specimens decreases from about 9.2μm to 4.5μm,with an increase in the addition of Y2O3 from 0 mol%to 3 mol%.The corresponding varistor’s voltage gradient markedly increases from 462 V/mm to 2340 V/mm,while the nonlinear coefficient decreases from 22.3 to 11.5,***,the characteristics of deep trap levels in these ZnO samples are investigated by measuring their dielectric *** trap energy level and capture cross section evaluated by relaxation peak of the Cole-Cole plot vary slightly as the addition of Y2O3 *** traps may be ascribed to the intrinsic defects of ZnO lattice.

关键词： ZnO varistors Y2O3 electrical properties deep trap levels

Testing local realism in P → VV decays

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2010年第5期53卷 870-875页

作者： li Junli1 & QIAO CongFeng1,2 1department of physics,Graduate university of Chinese Academy of Sciences,beijing 100049,china 2Theoretical physics Center for Science Facilities(TPCSF),Chinese Academy of Sciences,beijing 100049,china 1. department of physics Graduate University of Chinese Academy of Sciences Beijing 100049 China2. Theoretical Physics Center for Science Facilities (TPCSF) Chinese Academy of Sciences Beijing 100049 China

It was found that the vector meson pair from the pseudoscalar decays can form an entangled *** this work we give out detailed explanations on the polarization correlation of the two entangled vector *** is demonstrated that an experimental test of the Clauser-Horne inequality can be carried out through measuring the azimuthal distribution of four pseudoscalars in the cascade decay ηc→ VV →(PP)(PP),and the measurement of this process is feasible with the current running experiments in tau-charm ***,a brief discussion on the polarization correlation of the two vector mesons from B → VV decays is also presented.

关键词： nonlocality test high energy experiment meson decays

Building a next generation Internet with source address validation architecture

在线全文

学校读者我要写书评

暂无评论

Science in china(Series F) 2008年第11期51卷 1681-1691页

作者： WU JianPing1,3,REN Gang1,3 & li Xing2,3 1 department of Computer Science,tsinghua university,beijing 100084,china 2 department of Electronic Engineering,tsinghua university,beijing 100084,china 3 tsinghua National Laboratory for Information Science and Technology(TNlist) ,beijing 100084,china department of Computer Science Tsinghua University Beijing 100084 China department of Electronic Engineering Tsinghua University Beijing 100084 China tsinghua National Laboratory for Information Science and Technology (TNlist) Beijing 100084 China

The IP packet forwarding of current Internet is mainly destination based. In the forwarding process, the source IP address is not checked in most *** causes serious security, management and accounting problems. Based on the drastically increased IPv6 address space, a ＂source address validation architecture＂（SAVA） is proposed in this paper, which can guarantee that every packet received and forwarded holds an authenticated source IP address. The design goals of the architecture are lightweight, loose coupling, ＂multi-fence support＂ and incremental deployment. This paper discusses the design and implementation for the architecture, including inter-AS, intra-AS and local subnet. The performance and scalability of SAVA are described. This architecture is deployed into the CNGI-CERNET2 infrastructure a large-scale native IPv6 backbone network of the china Next Generation Internet project. We believe that the SAVA will help the transition to a new, more secure and dependable Internet.

关键词： IP source address validation network architecture network security