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Effect of trace Zn,P and Mg additions on microstructure and mechanical properties of Nb-Si-Ti alloys

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Progress in Natural Science:Materials International 2011年第2期21卷 139-145页

作者： Mei-ling WU,Shu-suo LI,Li-wu JIANG,Sheng-kai GONG,Ya-fang HAN school of Materials Science and Engineering,beihang university,beijing 100191,China school of Materials Science and Engineering Beihang University Beijing 100191 China

The effects of Zn,P and Mg additions on the microstructure and mechanical properties of Nb-22Ti-3.i alloys were studied. The phases of Nbss and Nb3.i presented in Nb-22Ti-3.i(AC1),Nb-22Ti-3.i-0.2Zn(AC2) and Nb-22Ti-3.i-0.2Mg alloys(AC3.. The Nb-22Ti-3.i-0.2P(AC4) alloy consisted of Nbss,Nb3.i network and eutectic cell of Nbss/α-*** the addition of Zn,the Nb3.i network was broken and the volume fraction of Nbss increased from 92%to 96%.The values of fracture toughness of the alloy AC2 at ambient temperature increased from 22,58 MPa·m1/2to 26.41 MPa·m1/*** values of compressive strength for the Zn-added alloy at ambient temperature and 1 250℃increased from 1 525.10 MPa to 1 652.44 MPa,and from 268.52 MPa to 284.18 MPa,*** with the alloy AC1,the addition of P promoted the formation ofα-Nb5Si phase but the values of fracture toughness and compressive strength of alloy at room temperature and 1 250℃*** contrast,the addition of Mg improved the compressive strength at ambient temperature and 1250℃from 1 525.10 MPa to 1 618.08 MPa and from 268.52 MPa to 3.8.28 MPa,*** relationship between the microstructure and the mechanical properties was discussed.

关键词： Nb-Si-Ti alloy Zn addition P Mg microstructure mechanical property

A New Scheme and Microstructural Model for 3. Full 5-directional Braided Composites

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Chinese Journal of Aeronautics 2010年第1期23卷 61-67页

作者： Zhang Fan,Liu Zhenguo,Wu Zhe,Tao Guoquan school of Aeronautic Science and Engineering,beijing university of Aeronautics and Astronautics,{3.,China [a] school of Aeronautic Science Engineering Beijing University of Aeronautics Astronautics Beijing 100191 China

Three-dimensional（3.D）braided composites are a kind of advanced ones and are used in the aeronautical and astronautical fields more widely. The advantages, usages, shortages and disadvantages of 3. braided composites are analyzed, and the possible approach of improving the properties of the materials is presented, that is, a new type of 3. full 5-directional braided composites is developed. The methods of making this type of preform are proposed. It is pointed out that the four-step braiding which is the most possible to realize industrialized production almost has no effect on the composites＇ properties. By analyzing the simulation model,the advantages of the material compared with the 3. 4-directional and 5-directional materials are presented. Finally, a microstructural model is analyzed to lay the foundation for the future theoretical analysis of these composites.

关键词： 3. braided fabrics four-step braiding 3. full 5-directional braided composites preform microstructure

Study on NDVI-T_s space by combining LAI and evapotranspiration

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Science China Earth Sciences 2006年第7期49卷 747-754页

作者： HAN Lijuan1,2,3. WANG Pengxin4, YANG Hua1,2,3. LIU Shaomin1,2,3.& WANG Jindi1,2,3.1. Research Center for Remote Sensing and GIS, school of Geography, beijing Normal university, beijing 100875, China 2. State Key Laboratory of Remote Sensing Science, beijing 100875, China 3. beijing Key Laboratory for Remote Sensing of Environment and Digital Cities, beijing 100875, China 4. Department of Information Management, College of Information and Electronic Engineering, China Agricultural university, beijing 100083. China 1. Research Center for Remote Sensing and GIS School of Geography Beijing Normal University Beijing 100875 China 2. State Key Laboratory of Remote Sensing Science Beijing 100875 China 3. beijing Key Laboratory for Remote Sensing of Environment and Digital Cities Beijing 100875 China 4. Department of Information Management College of Information and Electronic Engineering China Agricultural University Beijing 100083 China

This paper focuses on interpreting the different spatial relationships between NDVI and Ts, a triangular or a trapezoid, and on analyzing transformation conditions, the physical and ecological meanings of the vegetation index-surface temperature space as well. Further, we use the Tempera-ture-Vegetation Dryness Index (TVDI) to explain the existent meaning of a triangular space after NDVI reaches its saturated state by employing the relationships between NDVI, LAI and evapotranspiration. The specific relations between NDVI and Ts are useful for describing, validating and updating land surface models.

关键词： NDVI, land surface temperature, evapotranspiration, leave area index.

Threshold quantum secure direct communication without entanglement

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Science China(Physics,Mechanics & Astronomy) 2008年第2期51卷 176-183页

作者： YANG YuGuang1,3.& WEN QiaoYan2 1 College of Computer Science and Technology, beijing university of Technology, beijing 100022, China 2 {3. of Science, beijing university of Posts and Telecommunications, beijing 100876, China 3.State Key Laboratory of Information Security (Graduate {3. of Chinese Academy of Sciences), beijing 100049, China 1. College of Computer Science and Technology Beijing University of Technology Beijing 100022 China 3. State Key Laboratory of Information Security (Graduate school of Chinese Academy of Sciences) Beijing 100049 China 2. school of Science Beijing University of Posts and Telecommunications Beijing 100876 China

For the first time, a threshold quantum secure direct communication (TQSDC) scheme is presented. Similar to the classical Shamir's secret sharing scheme, the sender makes n shares, S1, …, Sn of secret key K and each receiver keeps a share secretly. If the sender wants to send a secret message M to the receivers, he en-codes the information of K and M on a single photon sequence and sends it to one of the receivers. According to the secret shares, the t receivers sequentially per-form the corresponding unitary operations on the single photon sequence and ob-tain the secret message M. The shared shares may be reusable if it can be judged that there is no eavesdropper in line. We discuss that our protocol is feasible with current technology.

关键词： quantum secure direct communication threshold secure direct communication quantum secret sharing

Quick image-processing method of UAV without control points data in earthquake disaster area

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中国有色金属学会会刊：英文版 2011年第S3期21卷 523-528页

作者： LI Chang-chun1, ZHANG Guang-sheng1, LEI Tian-jie2, 3. GONG A-du2, 3.1. school of Surveying & Land Information Engineering, Henan Polytechnic university, Jiaozuo 454000, China 2. Key Laboratory of Environmental Change and Natural Disaster, Ministry of Education, beijing Normal university, beijing 100875, China 3. Ministry of Civil Affairs/Ministry of Education of China Academy of Disaster Reduction and Emergency Management, beijing Normal university, beijing 100875, China [a] school of Surveying & Land Information Engineering Henan Polytechnic University Jiaozuo 454000 China [b] Key Laboratory of Environmental Change and Natural Disaster Ministry of Education Beijing Normal University Beijing 100875 China [c] Ministry of Civil Affairs/Ministry of Education of China Academy of Disaster Reduction and Emergency Management Beijing Normal University Beijing 100875 China

The methods of unmanned aerial vehicles images splicing rapidly and rectifying without control points data, only using auxiliary data recorded by unmanned aerial vehicle (UAV) system, were researched. Two algorithms were proposed, including UAV images auto- splicing rapidly after image blocking and UAV images rectifying based on pseudo center points of auxiliary data. When SIFT algorithm for UAV images splicing is applied, the accuracy is very high, but the efficiency is very low. The splicing efficiency is improved greatly based on SIFT algorithm after image blocking. The results show that rectifying accuracy is very high and has no visual dislocation when pseudo center points of auxiliary data is applied.

关键词： unmanned aerial vehicles SIFT algorithm blocking quickly splicing rectification

Some basic concepts and problems on the petrogenesis of intra-plate ocean island basalts

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Chinese Science Bulletin 2009年第22期54卷 4148-4160页

作者： NIU Yaoling1,2,3.1 Department of Earth Sciences, Durham university, Durham DH1 3.E, UK 2 school of Earth Sciences and Resources, China university of Geosciences, {3. 100083. China 3.school of Earth and Space Sciences, Peking university, {3. 100871, China Department of Earth Sciences Durham University Durham DH1 3LE UK school of Earth Sciences and Resources China University of Geosciences Beijing 100083 China school of Earth and Space Sciences Peking University Beijing 100871 China

Basaltic magmatism that builds intra-plate ocean islands is often considered to be genetically associated with "hotspots" or "mantle plumes". While there have been many discussions on why ocean island basalts (OIB) are geochemically highly enriched as an integral part of the mantle plume hypothesis, our current understanding on the origin of OIB source material remains unsatisfactory, and some prevailing ideas need revision. One of the most popular views states that OIB source material is recycled oceanic crust (ROC). Among many problems with the ROC model, the ocean crust is simply too depleted (e.g., [La/Sm]PM > 1) OIB. Another popular view states that the enriched component of OIB comes from recycled continental crust (RCC, i.e.; terrigenous sediments). While both CC and OIB are enriched in many incompatible elements (e.g., both have [La/Sm]PM >>1), the CC has characteristic enrichment in Pb and deletion in Nb, Ta, P and Ti. Such signature is too strong to be eliminated such that CC is unsuitable as source material for OIB. Plate tectonics and mantle circulation permit the presence of ROC and RCC materials in mantle source regions of basalts, but they must be volumetrically insignificant in contributing to basalt magmatism. The observation that OIB are not only enriched in incompatible elements, but also enriched in the progressively more incompatible elements indicates that the enriched component of OIB is of magmatic origin and most likely associated with low-degree melt metasomatism. H2O and CO2 rich incipient melt may form in the seismic low velocity zone (LVZ). This melt will rise because of buoyancy and concentrate into a melt rich layer atop the LVZ to metasomatize the growing lithosphere, forming the metasomatic vein lithologies. Erupted OIB melts may have three components: (1) fertile OIB source material from depth that is dominant, (2) the melt layer, and (3. assimilation of the metasomatic

关键词：岩石成因论海洋 OIB 矿物学

Displacement residual based DDM matching algorithm

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Science China(Information Sciences) 2012年第9期55卷 2090-2101页

作者： ZHANG Lin 1,2,ZHOU Zhong 1,2,LIU Lin 1,2 & WU Wei 1,2 1 State Key Laboratory of Virtual Reality Technology and Systems,beihang university,beijing 100191,China 2 school of Computer Science and Engineering,beihang university,beijing 100191,China 1. State Key Laboratory of Virtual Reality Technology and Systems Beihang University Beijing 100191 China2. School of Computer Science and Engineering Beihang University Beijing 100191 China

High level architecture(HLA) is the prevailing standard for modeling and *** data distribution management(DDM) service of HLA is defined for reducing the delivery of irrelevant *** key in DDM implementation is the region overlap computation,*** matching between update and subscription *** algorithms usually make a compromise between region fidelity and network *** paper takes both the matching algorithm efficiency and bandwidth cost into *** main contributions are:1) illustrating the relationship between region changes and overlap changes,as helps reduce the number of region matching and then improves the total matching efficiency;2) classifying region updates into two types of data expression,snapshot and *** network traffic will be reduced by transmitting only residual data instead of full region representations ***,a region matching algorithm called displacement residual-based DDM matching(DRBM) is proposed in the *** analysis,algorithm implementation and experiment evaluation are *** results show that DRBM provides better matching performance and significant network payload reductions especially when there is a large number of changing regions.

关键词： distributed simulation high level architecture data distribution management region snapshot region residual

Optimal reactions for the synthesis of superheavy nucleus ^(270)Hs

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Science China(Physics,Mechanics & Astronomy) 2006年第6期49卷 641-648页

作者： LIU Zuhua1,3.& BAO Jingdong1,2 1. Key Laboratory of Beam Technology and Material Modification of Ministry of Education, beijing Normal university, beijing 100875, China 2. Physics Department, beijing Normal university, beijing 100875, China 3. China Institute of Atomic Energy, beijing 102413. China Key Laboratory of Beam Technology Material Modification of Ministry of Education Beijing Normal University Beijing 100875 China Physics Department Beijing Normal University Beijing 100875 China China Institute of Atomic Energy Beijing 102413 China

The superheavy nucleus 270Hs is expected to be a “double-magic” deformed nucleus. We have calculated its cross sections of evaporation residue for the reactions 248Cm(26Mg,4n)270Hs, 244Pu(3.Si,4n)270Hs, 23.U(3.S,4n)270Hs and 226Ra(48Ca,4n)270Hs using a two-parameter Smoluchowski equation. It is found from our results that 226Ra(48Ca,4n)270Hs and 23.U(3.S,4n)270Hs are two optimal reactions for the synthesis of the superheavy nucleus 270Hs due to their large negative Q-values.

关键词： diffused fusion barrier,Smoluchowski equation,superheavy nuclei.

A new DNA algorithm to solve graph coloring problem

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Progress in Natural Science:Materials International 2007年第6期17卷 733-738页

作者： Jiang Xingpeng1, Li Yin2, Meng Ya3.and Meng Dazhi2(1. National Laboratory of Pattern Recognition,Institute of Automation, Chinese Academy of Sciences, beijing 100080, China 2. College of Applied Sciences, beijing university of Technology, beijing 100022, China 3. school of Science, beijing Institute of Technology, beijing 100081, China) National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100080 China College of Applied Sciences Beijing University of Technology Beijing 100022 China school of Science Beijing Institute of Technology Beijing 100081 China

Using a small quantity of DNA molecules and little experimental time to solve complex problems successfully is a goal of DNA computing. Some NP-hard problems have been solved by DNA computing with lower time complexity than conventional computing. However, this advantage often brings higher space complexity and needs a large number of DNA encoding molecules. One example is graph coloring problem. Current DNA algorithms need exponentially increasing DNA encoding strands with the growing of problem size. Here we propose a new DNA algorithm of graph coloring problem based on the proof of four-color theorem. This algorithm has good properties of needing a relatively small number of operations in polynomial time and needing a small number of DNA encoding molecules (we need only 6R DNA encoding molecules if the number of regions in a graph is R).

关键词： DNA computing NP-hard problem graph coloring problem.