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Competent predicate abstraction in model checking

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Science china(Information Sciences) 2011年第2期54卷 258-267页

作者： LI Li1,2.3. SONG XiaoYu4, GU Ming2.3.& LUO XiangYu2.3.1{3. of Computer Science & Technology, tsinghua university, Beijing {2., china 2.ey Laboratory for Information System Security, Ministry of Education of china, Beijing {2., china 3.chool of Software, tsinghua university, Beijing {2., china 4{3. of ECE, Portland State university, Portland, Oregon 972.7, USA department of Computer Science & Technology Tsinghua University Beijing China Key Laboratory for Information System Security Ministry of Education of China Beijing China School of Software Tsinghua University Beijing China department of ECE Portland State University Portland USA

The paper presents a new approach to computing the abstract state and a maximum weight heuristic method for finding the shortest counter-example in verification of imperative programs. The strategy is incorporated in a verification system based on the counterexample-guided abstraction refinement method. The proposed method slashes both the size of the abstract state space and the number of invokes of a decision procedure. A number of benchmarks are employed to evaluate the effectiveness of the approach.

关键词： program model checking predicate abstraction weight heuristic

New evidence for lack of CMB power on large scales

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Science china(Physics,Mechanics & Astronomy) 2010年第3期53卷 567-570页

作者： LIU Hao1 & LI TiPei1,2.3.1 Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, china 2.{3. of Physics & Center for Astrophysics,{2., Beijing 100084, china 3.{3. of Engineering Physics & Center for Astrophysics,{2., Beijing 100084, china Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China department of Physics & Center for Astrophysics Tsinghua University Beijing China department of Engineering Physics & Center for Astrophysics Tsinghua University Beijing China

A digitalized temperature map is recovered from the first light sky survey image published by the Planck team, from which an angular power spectrum of the cosmic microwave background (CMB) is derived. The amplitudes of the low multipoles (low-l) measured from the preliminary Planck power spectrum are significantly lower than those reported by the WMAP team. Possible systematical effects are far from enough to explain the observed low-l differences.

关键词： cosmology cosmic microwave background data analysis

TEXTURE DETERMINATION OF THIN FILM ZrO_2.BY ELECTRON DIFFRACTION

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Acta Metallurgica Sinica(English Letters) 1993年第12期6卷 472-473页

作者： WANG Yinghua tsinghua university,Beijing,china {2. of Materials Science and Engineering,{3. university,Beijing 100084,china tsinghua Univ Beijing China

A method for semi-quantitative determination of thin film texture using electron diffrac- tion is *** texture state of a zirconia thin film with a cubic structure has been determined in this way and is presented as an... 详细信息

关键词： texture thin film electron diffraction ZrO_2

Luminescence of Eu^(2.) in Strontium Aluminum Oxide System with Long Decay Property

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Chinese Chemical Letters 1998年第4期9卷 401-402页

作者： Yong QIU and Hai Tao SUN(department of chemistry,{2., Beijing {3.) department of chemistry Tsinghua University Beijing 100084 China

A long decay luminescent powder based upon the strontium aluminum oxide system with Eu2. as the activator was produced. It was found that the variation of the molar ratio of Al to Sr leads to a change in emission colo... 详细信息

关键词： luminescence of Eu^(2.) strontium aluminum oxide emission

Analysis on cohesive crack opening displacement considering the strain softening effect

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Science china(Physics,Mechanics & Astronomy) 2006年第1期49卷 88-101页

作者： WANG Limin1, XU Shilang2.& ZHAO Xiqiang3.1. Mechanics department, Shandong university of Technology, Zibo 2.5049,{2. 2. Civil Engineering department, Dalian university of Technology, Dalian 11602.,{2. 3. Mathematics department, Ocean university of{2., Qingdao 2.6071,{2. Mechanics department Shandong University of Technology Zibo China Civil Engineering department Dalian University of Technology Dalian China Mathematics department Ocean University of China Qingdao China

In order to investigate the crack propagation in quasi-brittle materials like rock, ceramic and concrete, Hillerborg and his co-researchers abstracted the fracture process zone in front of a stress free crack in terms of a “fictitious crack zone”. On the fictitious crack zone, cohesive stresses distribute following a given softening relationship of stress vs. crack opening. Based on the polynomial or power series expression of cohesive crack opening displacement, the relationship of the cohesive stress vs. the crack opening displacement is established using elastic theory and integral equation, and some unknown physics variables are obtained using variation approach. The calculation results gained in this paper are close to the experimentally test ones.

关键词： cohesive crack, softening, dissipation work, variation approach.

Preparation of MWNTs/Al_2._3.composites and their mechanical and electrical properties

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Science china(Technological Sciences) 2005年第6期48卷 622-631页

作者： FAN Jinpeng1,2. ZHAO Daqing1,2. XU Zening1,2.& WU Minsheng1,2.1. department of Mechanical Engineering, tsinghua university, Beijing {2., china 2. Key Laboratory for Advanced Manufacturing by Materials Processing Technology, tsinghua university, Beijing {2., china department of Mechanical Engineering Tsinghua University Beijing China Key Laboratory for Advanced Manufacturing by Materials Processing Technology Tsinghua University Beijing China

The mechanical and electrical properties of MWNTs/Al2.3.composite prepared fabricated by hot pressing are investigated. The relation between properties and microstructure of composites is also discussed. With 4wt% MWNTs as reinforcement, the fracture toughness of composite obtained reaches 5.55 MPa·m1/2. which is 80% higher than that of pure Al2.3.obtained in the same conditions. The main toughening mechanism is CNTs’ pinning alumina grain boundaries, and the pullout of CNTs takes effect also. Through adding 2.t% MWNTs and altering the mix method, the fracture toughness of the composite obtained is 3.97 MPa·m1/2. Furthermore, the electrical resistivity is as low as 8.4×10?3.?·m, decreasing by 14 orders of magnitude compared with pure alumina ceramics. The function of CNTs in composite is related to the distribution state of CNTs in composite, and the distribution state of CNTs in matrix is dependent on preparation procedures.

关键词： MWNTs, alumina, composite, fracture toughness, electrical properties.

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

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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 {2.,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 {2.,china Key Laboratory For Quantum Information and Measurements Department of Physics 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 Key Laboratory for Atomic and Molecular Nanosciences Tsinghua University Beijing 100084 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 2.+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

Parameter estimation for whole-body kinetic model of FDG metabolism

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Progress in Natural Science:Materials International 2006年第11期16卷 1164-1170页

作者： CUI Yunfeng~1, BAI Jing~1**, CHEN Yingmao~2.and TIAN Jiahe~2.1. department of Biomedical Engineering,{3., Beijing {2., china 2. department of Nuclear Medicine, General Hospital of PLA, Beijing 100853. china) department of Biomedical Engineering Tsinghua University Beijing 100084 China department of Nuclear Medicine General Hospital of PLA Beijing 100853 China

Based on the radioactive tracer [ ~ 18 F]2.fluoro-2.deoxy-D-glucose （FDG）, positron emission tomography （PET）, and compartment model, the tracer kinetic study has become an important method to investigate the glucose metabolic kinetics in human body. In this work, the kinetic parameters of three-compartment and four-parameter model for the FDG metabolism in the tissues of myocardium, lung, liver, stomach, spleen, pancreas, and marrow were estimated through some dynamic FDG-PET experiments. Together with published brain and skeletal muscle parameters, a relatively complete whole-body model was presented. In the liver model, the dual blood supply from the hepatic artery and the portal vein to the liver was considered for parameter estimation, and the more accurate results were obtained using the dual-input rather than the single arterial-input. The established whole-body model provides the functional information of FDG metabolism in human body. It can be used to further investigate the glucose metabolism, and also be used for the simulation and visualization of FDG metabolic process in human body.

关键词： compartment model FDG PET parameter estimation.

SIMULATION　CALCULATION　FOR　CHEMICAL　SPECIATION　OF　LEAD　BY　FEEDBACK　NEURAL　NETWORK

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Chinese Chemical Letters 1996年第3期7卷 265-266页

作者： Hua MO Bo DENG(department of chemistry,{2., Beijing, {3..) department of chemistry Tsinghua University Beijing 100084

The chemical speciations of Ph2. in the aqueous solution can becalculated using a Feedback Neural Network. The effects of CO3.2.), random errorand temperature on the simulation results were discussed. The results show... 详细信息

关键词： LEAD OF SPECIATION FEEDBACK CALCULATION BY