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Effects of Si Content and the Addition Amount of Al-3B Master Alloy on the Solidification Structures of Hypoeutectic Al-Si Alloys

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Rare Metals 2001年第3期20卷 168-173页

作者： Donghui wang,Jianguo Li, Yankang Zheng, Bingzhe Bai department of materials science and engineering, tsinghua university, beijing 100084, china 清华大学北京 100084

Effects of Si content and the addition amount of Al-3B master alloy on the solidification structures of hypoeutectic Al-Si alloys were studied. The addition amounts of the master alloy were 0.2%, 0.4%, 0.7% and 1% (mass fraction, so as the follows), respectively. The Si content of Al-Si binary alloys investigated varied from 1% to 11%. The observation of macrostructures of non-refined samples showed that 3% Si constitutes a transition point at which the minimum grain size can be obtained. It was also found that Al-3B master alloy can shift the transition point towards a higher Si value when its addition amount increases, making this point appear at 4%, 5% and 6% Si as its addition amount increases up to 0.4%, 0.7% and 1%, respectively.

关键词： Al-3B master alloy hypoeutectic Al-Si alloy grain refinement

A Rationalization of Sympathetic Nucleation-Ledgewise Growth Theory of Bainite Transformation in Fe-C Alloys

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Journal of materials science & Technology 2001年第4期17卷 433-438页

作者： Zhigang YANG, Chi ZHANG, Hongsheng FANG, Jinbo YANG, Bingzhe BAI and Jiajun wang department of materials science and engineering, tsinghua university.beijing 100084, china Dept. of Mat. Sci. and Eng. Tsinghua Univ. Beijing 100084 China

Based on the classic diffusion controlled nucleation and goth theory, the sympathatic nucleation- ledgewise growth mechanism of bainite was studied theoretically for low carbon Fe-C alloys. The rationality of the occurrence of sympathetic nucleation on the terraces of ledges compating with lateral ledge growth and other sites nucleation was demonstrated by the present work quantita- tively The calculations indicated that low reaction temperatures and high carbon concentrations may favor the sympathetic nucleation, thus accounting for the formation of multilayer structures of bainite.

关键词： A Rationalization of Sympathetic Nucleation-Ledgewise Growth Theory of Bainite Transformation in Fe-C Alloys Fe

A normalized thoracic coordinate system for atlas mapping in 3D CT images

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Progress in Natural science:materials International 2008年第1期18卷 111-117页

作者： Hongkai wang,Jing Bai*,Yonghong Zhang department of Biomedical engineering,tsinghua university.beijing 100084,china department of Biomedical engineering Tsinghua University Beijing 100084 China

In this paper,a normalized thoracic coordinate system(NTCS)is defined for rapidly mapping the 4D thoracic organ atlas into indi- vidual CT volume *** coordinate system is defined based on the thoracic *** coordinate values are normalized by the size of the individual thorax so that this coordinate system is universal to different *** compensating the respiratory motion of the organs,a 4D dynamic torso atlas is introduced.A method for mapping this dynamic atlas into the individual image using the NTCS is also *** this method,the dynamic atlas was mapped into the clinical thoracic CT images and rough positions of the organs were found *** NTCS-based 4D atlas mapping method may provide a novel way for estimating the thoracic organ positions in low-resolution molecular imaging modalities,as well as in modern 4D medical images.

关键词： Atlas mapping Registration Segmentation Molecular imaging

A secure multi-party computation solution to intersection problems of sets and rectangles

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Progress in Natural science:materials International 2006年第5期16卷 538-545页

作者： LI Shundong, DAI Yiqi, wang Daoshun and LUO Ping (department of Computer science and Technology, beijing Normal university, beijing 100875, china department of Computer science and Technology, tsinghua university, beijing 100084, china) department of Computer science and Technology Beijing Normal University Beijing 100875 China department of Computer science and Technology Tsinghua University Beijing 100084 China

Secure multi-party computation (SMC) is a research focus in international cryptographic community. At present, there is no SMC solution to the intersection problem of sets. In this paper, we first propose a SMC solution to this problem. Applying Cantor encoding method to computational geometry problems, and based on the solution to set-intersection problem, we further propose solutions to points inclusion problem and intersection problem of rectangles and further prove their privacy-preserving property with widely accepted simulation paradigm. Compared with the known solutions, these new solutions are of less computational complexity and less communication complexity, and have obvious superiority in computational and communication complexity.

关键词： Cantor encoding secure multi-party computation set-intersection rectangle-intersection computational complexity.

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 < FeNi-CNTs< *** areal density of as-prepared coatings is only 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

Preparation of NiFe binary alloy nanocrystals for nonvolatile memory applications

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science china(Technological sciences) 2010年第9期53卷 2320-2322页

作者： wang Li,SUN HongFang,ZHOU HuiHua & ZHU Jing beijing National Center for Electron Microscopy Laboratory,department of materials science and engineering,tsinghua university.beijing 100084,china beijing National Center for Electron Microscopy Laboratory Department of Materials Science and Engineering Tsinghua University Beijing China

In this work,an idea which applies binary alloy nanocrystal floating gate to nonvolatile memory application was *** relationship between binary alloy’s work function and its composition was discussed theoretically.A nanocrystal floating gate structure with NiFe nanocrystals embedded in SiO2 dielectric layers was fabricated by magnetron *** micro-structure and composition deviation of the prepared NiFe nanocrystals were also investigated by TEM and EDS.

关键词： nanocrystal nonvolatile memory work function magnetron sputtering

Viscosity,thermal diffusivity and Prandtl number of nanoparticle suspensions

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Progress in Natural science:materials International 2004年第10期14卷 82-86页

作者： wang Buxuan ,ZHOU Leping and PENG Xiaofeng (Thermal engineering department,tsinghua university.beijing100084,china) Thermal Eng. Dept. Tsinghua Univ. Beijing 100084 China

Using our reported experimental data of effective thermal conductivity,specific heat capacity and viscosity for CuO nanoparticle suspensions,the corresponding thermal diffusivity and Prandtl number are *** the hard sphere model and consid-ering effects of particle clustering and surface adsorption,the increase of viscosity for nanoparticle suspension observed is *** is shown that the effective thermal conductivity will be strongly affected by the formation and correlated spatial distribution of nanoparticle clusters when compared to viscosity in hosting liquid.

关键词： nanoparticle suspension viscosity thermal diffusivity Prandtl number

Comparison of corrosion behavior of ZL104 alloy at as-cast and heat treatment states

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Rare Metals 2002年第3期21卷 224-228页

作者： wang Donghui, ZHENG Yankang, LI ianguo, and BAI Bingzhedepartment of materials science and engineering, tsinghua university, beijing 100084, china department of materials science and engineering Tsinghua University 北京 100084

The corrosion behavior of ZL104 alloy at different states (as-cast and heattreatment) in salt spray corrosion (SSC) was studied. The results show that the sample treated afterrefinement and modification has the least corrosive resistance compared with the sample bearingas-cast structure at the beginning of the corrosion. As the corrosion process continued, however,the trend reversed itself. After 44 h continuous corrosion, the corrosive rates of all samples tendto be stable. After experiments, the sample bearing as-cast structure had the most corrosiveproducts on the surface whereas the sample being refined and modified had the least products. TheFourier transformation infrared spectroscopy (FTIR) analyses of the corrosion products show thatthese products are composed of hydroxyl-containing substances.

关键词： ZL104 alloy modification salt spray corrosion (SSC)

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