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Scalable and Identifier/Locator-Splitting Routing Protocol for Mobile Ad Hoc Networks

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china Communications 2012年第1期9卷 102-110页

作者： Wang Haiquan Chen Meng Hu Junshun Xia Chunhe beijing key laboratory of Network technology Beihang University Beijing 100191 P. R. China School of Computer Science and Engineering Beihang University Beijing 100191 P. R. China state key laboratory of virtual reality technology and System Beihang University Beijing 100191 P. R. China School of So ware Beihang University Beijing 100191 P. R. China

In the traditional Intemet Protocol （IP） architecture, there is an overload of IP sermntic problems. Existing solutions focused mainly on the infrastructure for the fixed network, and there is a lack of support for Mobile Ad Hoc Networks （MANETs）. To improve scalability, a routing protocol for MANETs is presented based on a locator named Tree-structure Locator Distance Vector （TLDV）. The hard core of this routing method is the identifier/locator split by the Distributed Hash Table （DHT） method, which provides a scalable routing service. The node locator indicates its relative location in the network and should be updated whenever topology changes, kocator space ks organized as a tree-structure, and the basic routing operation of the TLDV protocol is presented. TLDV protocol is compared to some classical routing protocols for MANETs on the NS2 platform Results show that TLDV has better scalability. key words：

关键词： MANETs multi-hop routing identifi- er/locator split distributed hash tables

Effect of welding speed on the material flow patterns in friction stir welding of AZ31 magnesium alloy

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Rare Metals 2007年第2期26卷 158-162页

作者： ZHANG Hua wu Huiqiang Huang Jihua LIN Sanbao wu Lin Materials Science and Engineering School University of Science and Technology Beijing Beijing 100083 China beijing Institute of Astronautical systems Engineering Beijing 100076 China state key Lab of Advanced Welding Production technology Harbin Institute of Technology Harbin 150001 China

The clear zigzag-line pattern on transverse cross sections can be used to explain the formation mechanism of the weld nugget when friction stir welded AZ31 magnesium alloy without any other insert material is used as mark. It provides a simple and useful method to research the joining mechanism of friction stir welding. The rotation speed is kept at 1000 r/min and the welding speed changes from 120 mm/min to 600 mm/min. The macrostructure on the transverse cross section was divided into several parts by faying surface. The results show that the shape and formation procedure of the weld nugget change with the welding speed. There are two main material flows in the weld nugget： one is from the advancing side and the other is from the retreating side. A simple model on the weld nugget formation of FSW is presented in this article.

关键词： AZ31 magnesium alloy friction stir welding faying surface materials flow formation model

Identification of yak lactate dehydrogenase B gene variants by gene cloning

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Science china(Life Sciences) 2008年第5期51卷 430-434页

作者： ZHENG YuCai1, ZHAO XingBo2, zhou Jing1, PIAO Ying1, JIN SuYu1, HE QingHua1, HONG Jian1, LI Ning2 & wu ChangXin2 1 College of Life Science and technology, Southwest university for Nationalities, Chengdu 610041, china 2 state key laboratory for Agrobiotechnology and Ministry of Agriculture key laboratory of Animal Genetics and Breeding, College of Animal Science and technology, china Agricultural university, beijing 100094, china College of Life Science technology Southwest University for Nationalities Chengdu 610041 China state key laboratory for Agrobiotechnology Ministry of Agriculture key laboratory of Animal Genetics Breeding College of Animal Science technology China Agricultural University Beijing 100094 China

Native polyacrylamide gel electrophoresis showed that two types of lactate dehydrogenase (LDH) existed in yaks. Based on the electrophoresis characteristics of LDH isoenzymes, yak LDH variants were speculated to be the gene mutation on H subunit encoded by B gene. According to the mobility in electrophoresis, the fast-band LDH type was named LDH-Hf and the slow-band LDH type LDH-Hs. In order to reveal the gene alteration in yak LDH variants, total RNA was extracted from heart tissues of yaks with different LDH variants, and cDNAs of the two variants were reverse transcripted. Two variants of B genes were cloned by RT-PCR. Sequence analysis revealed that four nucleotides differed between LDH-Bf and LDH-Bs, which resulted in two amino acids alteration. By Deepview software analysis of the conformation of yak LDH1 variants and H subunit, these four nucleotides altered two amino acids that generated new hydrogen bonds to change the hydrogen bonds network, and further caused subtle conformational changes between the two LDH variants.

关键词： yak lactate dehydrogenase genetic variants gene cloning molecular modeling

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卫星在轨运行视景仿真中的真实感实现

系统仿真学报 2009年第S1期21卷 87-90,94页

作者：王成雷小永戴树岭北京航空航天大学虚拟现实技术与系统国家重点实验室北京100191 北京航空航天大学自动化科学与电气工程学院自动控制系北京100191

针对卫星系统设计与研制对视景仿真中真实感的需要,提出了几种视觉真实感实现的方法,采用NormalMap,CubeMap和粒子系统等技术实现卫星表面的锡纸效果、金属质感和发动机喷管的火焰效果,采用Billboard,RibbonTrail和纹理动画等技术实现... 详细信息

针对卫星系统设计与研制对视景仿真中真实感的需要,提出了几种视觉真实感实现的方法,采用NormalMap,CubeMap和粒子系统等技术实现卫星表面的锡纸效果、金属质感和发动机喷管的火焰效果,采用Billboard,RibbonTrail和纹理动画等技术实现卫星轨道、轨迹、红外扫描和爆炸效果,采用Skybox,Lensfare等技术实现由地球、太阳、大气层和星空组成的太空背景。仿真结果显示这几种方法取得了良好的真实感。

关键词：卫星视景仿真法向量贴图环境贴图公告板丝带轨迹天空盒透镜光照

Quantitative analysis of soil pores under natural vegetation successions on the Loess Plateau

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Science china Earth Sciences 2010年第4期53卷 617-625页

作者： ZHAO Shiwei1,ZHAO YongGang1,2 & wu JinShui3 1 state key laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation,Northwest Agriculture & Forestry university,Yangling 712100,china 2 Graduate university of Chinese Academy of Sciences,beijing 100049,china 3 Institute of Subtropical Agriculture,Chinese Academy of Sciences,Changsha 410125,china 1. state key laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation Northwest Agriculture & Forestry University Yangling 712100 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Institute of Subtropical Agriculture Chinese Academy of Sciences Changsha 410125 China

Soil pore is a key attribute of the soil structure that affects soil reservoir under natural vegetation recovery on the Loess *** study is to quantitatively analyze soil pore parameters,measured with Computed Tomography(CT) at 15-57 mm depths under five different vegetation succession stages using a concept of substituting "space" for "time" in the Ziwuling Forest Region of the Loess *** results showed that the soil pore parameters,such as pore number,porosity,circularity,and fractal dimension,increased significantly under the natural vegetation successions and varied with the pattern climax community stage>pioneering arbor community stage>scrub community stage>herbaceous community stage>abandoned farmland stage,indicating that natural vegetation recovery could remarkably improve soil pore *** the vegetation succession,this positive effect will be strengthened gradually,which means that the soil pore parameters may appear to be best at the climax community *** organic matter content increased linearly with the soil pore parameters(P<0.001).Increased organic matter accumulation was one of the major reasons for the changes in soil pore characteristics in natural vegetation succession.

关键词： Computed Tomography Loess Plateau natural vegetation succession soil pore soil organic matter

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基于增强现实的遥现系统研究

系统仿真学报 2009年第S1期21卷 222-226页

作者：张炯雷小永戴树岭陈娜北京航空航天大学虚拟现实技术与系统国家重点实验室北京100191 北京航空航天大学自动化科学与电气工程学院自动控制系北京100191

传统遥现技术大多利用视频采集传输系统,让用户产生远端临场感,但因为缺少深度信息,很难产生较高的沉浸感,实用价值不高。利用虚拟现实中的增强现实理论,通过双路视频,获取远端场景的深度信息,并将目标对象从视频中提取出来与虚拟场景... 详细信息

传统遥现技术大多利用视频采集传输系统,让用户产生远端临场感,但因为缺少深度信息,很难产生较高的沉浸感,实用价值不高。利用虚拟现实中的增强现实理论,通过双路视频,获取远端场景的深度信息,并将目标对象从视频中提取出来与虚拟场景相结合,搭建一个新型的增强遥现原型系统。系统构建于internet的环境中,重点解决了双路网络视频同步传输,立体视觉深度提取,虚实场景融合三个问题,获得了良好的沉浸感。最后本文以虚拟会议室为研究对象,验证该系统的可行性。

关键词：增强现实遥现立体视觉同步传输

Formation mechanism of carbonate cemented zones adjacent to the top overpressured surface in the central Junggar Basin,NW china

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Science china Earth Sciences 2010年第4期53卷 529-540页

作者： YANG Zhi1,2,ZOU CaiNeng1,3,HE Sheng2,LI QiYan1,HE ZhiLiang3,wu HengZhi5,CAO Feng1,MENG XianLong4,WANG FuRong2 & XIAO Qilin21 state key laboratory of EOR,Research Institute of Petroleum Exploration & Development,Petrochina,beijing 100083,china 2 key laboratory of Tectonics and Petroleum Resources of Ministry of Education,china university of Geosciences,wuhan 430074,china 3 state key laboratory of EOR,Research Institute of Petroleum Exploration & Development,Petrochina,beijing 100083,china 4 Research Institute of Petroleum Exploration and Production,SINOPEC,beijing 100083,china 5 Southwest Branch Company,SINOPEC,Chengdu 610051,china 1. state key laboratory of EOR Research Institute of Petroleum Exploration & Development PetroChina Beijing 100083 China2. Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education China University of Geosciences Wuhan 430074 China3. State Key Laboratory of EOR Research Institute of Petroleum Exploration & Development Petrochina Beijing 100083 China5. Southwest Branch Company SINOPEC Chengdu 610051 China4. Research Institute of Petroleum Exploration and Production SINOPEC Beijing 100083 China

Carbonate cemented zones are normally adjacent to the top overpressured surface in the central Junggar Basin,NW *** carbon and oxygen isotopic compositions and petrological investigations of carbonate cements in the carbonate cemented zones indicate that:(1) carbonate cements are composed dominantly of ferrocalcite,ferroan dolomite,and ankerite;(2) carbonate cements are formed under a high temperature circumstance in the subsurface,and organic fluid migration has an important effect on the formation of them;and(3) carbon and oxygen ions in the carbonate cements migrate from the underlying overpressured *** suggests that the occurrence of carbonate cemented zones in this region results from multiple phases of organic fluid expulsion out of the overpressure compartment through geological *** study provides a plausible mechanism of the formation of carbonate cemented zones adjacent to the top overpressured surface in the clastic sedimentary basins,and has an important implication for understanding the internal correlation between the formation of carbonate cemented zones adjacent to top overpressured surface and geofluids expulsion out of overpressured system.

关键词： carbonate cemented zones formation mechanism stable carbon and oxygen isotopic top overpressured surface central Junggar Basin coal-bearing strata

Manipulating guest-responsive spin transition to achieve switchable fluorescence in a Hofmann-type framework

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Science china Chemistry 2024年第10期67卷 3339-3346页

作者： Xue-Ru wu Shu-Qi wu Zhi-Kun Liu Ming-Xing Chen Jun Tao Osamu Sato Hui-zhong Kou Engineering Research Center of Advanced Rare Earth Materials(Ministry of Education) Department of ChemistryTsinghua UniversityBeijing 100084China Institute for Materials Chemistry and Engineering&IRCCS Kyushu University744 MotookaNishi-kuFukuoka 819-0395Japan key laboratory of Cluster Science of Ministry of Education School of Chemistry and Chemical EngineeringLiangxiang CampusBeijing Institute of TechnologyBeijing 102488China Analytical Instrumentation Center College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

The change of fluorescence emission manipulated by spin state transition attracts considerable attention owing to its potential applications in magneto-optical switching ***,we report two two-dimensional(2D)Hofmann-type spin crossover(SCO)metal-organic frameworks(MOFs)[Fe^(Ⅱ)(PNI)_(2){Ag^(Ⅰ)(CN)_(2)}_(2)]·CHCl_(3)(3Ag·CHCl_(3))and[FeⅡ(PNI)_(2){AuⅠ(CN)_(2)}_(2)]·CHCl_(3)(3Au·CHCl_(3))based on the fluorescent ligand N-(4-pyridylmethyl)-1,8-naphthalimide(PNI).Both complexes exhibit interesting SCO behaviors switched by guest solvent molecules,namely three-step transitions for the solvated complexes and complete onestep hysteretic SCO for the desolvated ones,verified by temperature-dependent magnetic susceptibility measurements,Mossbauer spectra,structural analyses,and differential scanning calorimetry ***,temperature-dependent fluorescence spectra exhibit double peaks(monomer and excimer emission)with both emission peaks change consistent with the change in SCO properties during the solvent molecule *** this study,we integrated guest-responsive SCO behavior into MOFs to manipulate the multistability of spin state and fluorescence switching,providing a rational strategy for the development of stimuli-responsive multifunctional materials.

关键词： spin crossover fluorescence multifunctional materials metal-organic frameworks Hofmann-type

Effects of cooling rates on the mechanical properties of a Ti-based bulk metallic glass

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Science china(Physics,Mechanics & Astronomy) 2010年第3期53卷 394-398页

作者： XIAO YueHua, wu Yuan, LIU ZhiYuan, wu HongHui & Lü ZhaoPing state key laboratory for Advanced Metals and Materials, university of Science and technology beijing, beijing 100083, china 1. state key laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

Mechanical properties of the glassy specimens fabricated at different cooling rates with a composition of Ti40Zr25Cu12Ni3Be20 were systematically investigated. It was confirmed that faster cooling rates caused not only a larger amount of frozen-in free volume but also a higher glass transition temperature in the bulk glassy alloy. Increase in the free volume was found to favor plastic deformation and then to give rise to larger compressive plasticity, whilst the rise in the glass transition temperature seemed to be closely related to the higher yield strength. Moreover, the increase of yield strength and plasticity induced by fast cooling rates may also be associated with the residual stress generated during the fabrication process. Our results suggest that the deformation behavior of bulk metallic glasses is sensitive to various factors and influences from the other factors should be excluded as far as cooling-rate effects on bulk metallic glasses are considered.

关键词： bulk metallic glasses mechanical properties cooling-rate effects residual stress