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Synthesis,field emission and microwave absorption of carbon nanotubes filled with ferromagnetic nanowires

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science china(Technological sciences) 2010年第6期53卷 1453-1459页

作者： LV RuiTao1,KANG FeiYu1,GU JiaLin1,WANG KunLin2 & WU DeHai2 1 laboratory of Advanced Materials,Department of Materials science and Engineering,tsinghua university,beijing 100084,china 2 Department of Mechanical Engineering,tsinghua university,beijing 100084,china laboratory of Advanced Materials Department of Materials Science and Engineering Tsinghua University Beijing China Department of Mechanical Engineering Tsinghua University Beijing China

Carbon nanotubes filled with ferromagnetic metal nanowires (M-CNTs) were synthesized by using chlorine-contained benzene (***) as *** wall thicknesses of M-CNTs synthesized by trichlorobenzene are much thinner than those by precursor without Cl (***).As-synthesized thin-walled M-CNTs exhibit remarkably enhanced field electron emission performance with a low turn-on field of 0.3 V/μm and better field-emission ***-absorption coatings were made by dispersing as-synthesized M-CNTs into epoxy resin *** is found that the reflection losses in S-band (2-4 GHz),C-band (4-8 GHz) and X-band (8-12 GHz) are enhanced in the order of FeCoNi-CNTs 2.35 kg/m2 when the coating thickness is 2.0 *** demonstrates that M-CNTs are promising to be used as lightweight and wide-band microwave absorbers.

关键词： carbon nanotubes ferromagnetic nanowires field emission microwave absorption

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 1Department of Computer science & technology, tsinghua university, beijing 100084, china 2Key laboratory for information System Security, Ministry of Education of china, beijing 100084, china 3School of Software, tsinghua university, beijing 100084, china 4Department of ECE, Portland State university, Portland, Oregon 97207, 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

Evidence for existence of a close association between CD14 and CXCR4 on monocytic cell line U937

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Progress in Natural science:Materials International 2007年第8期17卷 979-982页

作者： Yang Hengwen Lan Canhui Chen Yinghua~(**) (laboratory of Immunology,Department of Biology,tsinghua university Protein science laboratory of MOE,beijing 100084,china) laboratory of Immunology Department of Biology Tsinghua University Beijing 100084 China Protein science laboratory Beijing 100084 China

The surface expression of HIV-1 coreceptors (CXCR4 and CCR5) on monocytes can be regulated by the ligand of CD14,and the susceptibility of the cells to HIV-1 is then *** previous study found that monoclonal antibody against CD14 could dramatically inhibit CXCR4-mediated chemotaxis and cell-cell *** on these studies,we explored potential relationship between CD14 and CXCR4 on monocytic cell line *** cytometry analysis showed that anti-CXCR4 monoclonal antibody (mAb) 12G5 strongly inhibited binding of the FITC-conjugated anti-CD14 monoclonal antibodies (TUK4 and UCHM1) to U937,while another CX- CR4-specific mAb B-R24 did not show any effect on this *** the other hand,two anti-CD14 monoclonal antibodies (TUK4 and UCH-M1) obviously inhibited the binding of the PE-conjugated anti-CXCR4 mAb 12G5 to U937 but did not inhibit the binding of mAb 12G5 to CXCR4-transfected 3T3 cells (***4),which indicates that the blocking of mAb 12G5 binding to CXCR4 by CD14- specific mAbs is not involved in the possibility that CD14-specific mAbs directly bind to *** results suggested existence of a close association between CD14 and CXCR4 on monocytic cell line U937.

关键词： CD14 CXCR4 cross-inhibition

Cloning and characterization of 37 kDa laminin receptor precursor in pearl oyster,Pinctada fucata

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Progress in Natural science:Materials International 2008年第2期18卷 233-238页

作者： Yaopeng Fu a,Liping Xie a,b,,Rongqing Zhang a,b,a Institute of Marine Biotechnology,Department of Biological sciences and Biotechnology,tsinghua university,beijing 100084,china b Protein science laboratory of the Ministry of Education,tsinghua university,beijing 100084,china Institute of Marine Biotechnology Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China Protein science laboratory of the Ministry of Education Tsinghua University Beijing 100084 China

A 1063 bp cDNA clone encoding a putative 37 kDa laminin receptor precursor (37 kDa LRP) is isolated from the mantle tissue of pearl oyster,Pinctada fucata. The amino acid sequence predicted from the cDNA sequence is 301 residues long,with a calculated molec-ular mass of 33.5 kDa. RT-PCR analysis shows that 37 kDa LRP mRNA is especially highly expressed in the mantle while widely expressed in several tissues. In situ hybridization analysis reveals that 37 kDa LRP is expressed in the outer epithelial cells of the mantle edge,suggesting its involvement in cell proliferation and secretion in P. fucata. The identification and characterization of 37 kDa LRP in the pearl oyster will help us to further understand the signal transduction in the processes of mantle epithelial cell proliferation and tissue formation.

关键词： 37 kDa laminin receptor precursor Mantle epithelial cell Pearl oyster

Online multiple instance regression

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Chinese Physics B 2013年第9期22卷 656-661页

作者：王志岗赵增顺张长水 Department of Automation Tsinghua UniversityState Key Laboratory of Intelligent Technologie and SystemsTsinghua National Laboratory for Information Science and Technology College of information and Electrical Engineering Shandong University of Science and Technology School of Control science and Engineering Shandong University

The multiple instance regression problem has become a hot research topic recently. There are several approaches to the multiple instance regression problem, such as Salience, Citation KNN, and MI-ClusterRegress. All of these solutions work in batch mode during the training step. However, in practice, examples usually arrive in sequence. Therefore, the training step cannot be accomplished once. In this paper, an online multiple instance regression method ＂OnlineMIR＂ is proposed. OnlineMIR can not only predict the label of a new bag, but also update the current regression model with the latest arrived bag. The experimental results show that OnlineMIR achieves good performances on both synthetic and real data sets.

关键词： mutiple instance regression online learning

Gas kinetic algorithm for flows in Poiseuille-like microchannels using Boltzmann model equation

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science china(Physics,Mechanics & Astronomy) 2005年第4期48卷 496-512页

作者： LI Zhihui1,2, ZHANG Hanxin1 & FU Song2 ⒈ national laboratory for CFD, Hypervelocity Aerodynamics Institute,china Aerodynamics Research and Development Center,Mianyang 621000,china 2.Department of Engineering Mechanics,tsinghua university,beijing 100084,china national laboratory for CFD Hypervelocity Aerodynamics Institute China Aerodynamics Research and Development Center Mianyang China Department of Engineering Mechanics Tsinghua University Beijing China

The gas-kinetic unified algorithm using Boltzmann model equation have been extended and developed to solve the micro-scale gas flows in Poiseuille-like micro-channels from Micro-Electro-Mechanical Systems (MEMS). The numerical modeling of the gas kinetic boundary conditions suitable for micro-scale gas flows is presented. To test the present method, the classical Couette flows with various Knudsen numbers, the gas flows from short microchannels like plane Poiseuille and the pressure-driven gas flows in two-dimensional short microchannels have been simulated and compared with the approximate solutions of the Boltzmann equation, the related DSMC results, the modified N-S solutions with slip-flow boundary theory, the gas-kinetic BGK-Burnett solutions and the experimental data. The comparisons show that the present gas-kinetic numerical algorithm using the mesoscopic Boltzmann simplified velocity distribution function equation can effectively simulate and reveal the gas flows in microchannels. The numerical experience indicates that this method may be a powerful tool in the numerical simulation of micro-scale gas flows from MEMS.

关键词： Boltzmann model equation, discrete velocity ordinate method, finite-difference scheme, Couette flow, Poiseuille flow, gas flow in short-microchannel.

Orthogonally linear polarized lasers (I)——principle and devices

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Progress in Natural science:Materials International 2005年第7期15卷 586-595页

作者： ZHANG Shulian and XU Ting (State Key laboratory of Precision Measurement technology and Instruments, Department of Precision Instruments, tsinghua university, beijing 100084, china) State Key laboratory of Precision Measurement technology and Instruments Department of Precision Instruments Tsinghua University Beijing 100084 China

Two kinds of orthogonally polarized lasers, i. e. Zeeman dual-frequency lasers and four-frequency ring lasers (laser gyros) have been developed since the invention of lasers, in which circularly polarized lights oscillate. This paper summarizes recent progress of the study on orthogonally linear polarized lasers with the standing wave cavity. Firstly, the expression of producing orthogonally linear polarized lights in standing wave cavity, i. e. laser frequency splitting, is given. Almost all the birefringence effects made in laser cavity are used to produce orthogonally linear polarized lights. The effect includes quartz crystal birefringence effect, calcite birefringence effect, stress (photo-elastic) birefringence effect and electro-optical birefringence effect. Secondly, several physical phenomena of orthogonally linear polarized lasers are discovered such as aberrance of frequency splitting curves caused by optical activity of quartz crystal, order-passing of longitudinal modes with frequency splitting and strong modes competition. Finally, because the traditional Zeeman dual frequency laser cannot output frequency difference larger than 3 MHz, the approaches of obtaining larger frequency difference are studied. The sequential results, several kinds of orthogonally polarized lasers, are described, such as birefringence dual frequency lasers outputting a frequency difference from 40 MHz to hundreds of megahertz, birefringence-Zeeman dual frequency lasers outputting a frequency difference from 1 MHz to hundreds of megahertz, the LD pumped YAG birefringence dual frequency laser outputting frequency difference of several gigahertz, and the lasers whose longitudinal mode spacing is c/4L instead of c/2L .

关键词： orthogonally polarized laser dual frequency laser intra-cavity birefringence Zeeman effect photo-elastic birefringence electro-optical birefringence frequency splitting.

Optimizing write operation on replica in data grid

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science china(information sciences) 2011年第1期54卷 1-11页

作者： XU PengZhi,WU YongWei,HUANG XiaoMeng, YANG GuangWen & ZHENG WeiMin Department of Computer science and technology,tsinghua university,beijing 100084,china Department of Computer science and technology Tsinghua University Beijing China

Replication technique can improve access performance and data availability of data grid systems. So far,most related work on data replication in data grid systems focuses on read-only *** write operations have been widely used in practice,its optimization problem has not been suciently *** this paper,we show that write requests from users can be processed by a nearest site,regardless of the location of latest written *** policy of write nearby instead of write to the latest replica can improve the performance of write operations,while inconsistency is caused between multiple ***,we propose two metadata management algorithms to make sure that users can retrieve up-to-date datasets at any *** extend OptorSim to support the implementation and evaluation of our *** results of simulation show that our scheme achieves performance gains up to 3.3 compared with WriteMaster scheme.

关键词： replication data grid simulation access latency

All-optical NOR gate based on injection-locking effect in a semiconductor laser

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光电子快报：英文版 2008年第1期4卷 33-37页

作者： HAN Liu-yan, ZHANG Han-yi, and GUO Yi-li State Key laboratory on Integrated Optoelectronics, national laboratory for information science and technology, De- partment of Electronic Engineering, tsinghua university, beijing 100084, china State Key laboratory on Integrated Optoelectronics National Laboratory for Information Science and Technology Department of Electronic Engineering Tsinghua University Beijing China

A scheme for all-optical NOR logic gate is proposed based on injection-locking effect in a semiconductor laser. In this scheme, signal light injection into the laser will cause frequency shift of laser modes, as a result, the probe light into the laser can be switched between injection-locked and unlocked status, and its output power will be modulated. Theoretical analysis for this scheme is carried out by using a model to describe the dynamics of the injection-locked laser. By numerical simulation, the influence of laser bias current, laser length, injected signal power and signal frequency on the output performance of NOR logic gate is quantitatively analyzed.

关键词：半导体激光器注入锁相效应全光或非门光纤通信