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An improved network layer protocol based on mobile IPv6

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Journal of Central South University 2001年第4期8卷 263-267页

作者： WANG Jian xin 1,HUANG Guo sheng 2.CHEN Song qiao 1,CHEN Jian er 1 (1.College of Information science and engineering, Central South University, {2. 410083, china 2.department of Physics and Electronic engineering, Jishou University, Jisho College of Information science and engineering Central South University Changsha China department of Physics and Electronic engineering Jishou University Jishou China

The mobile IPv6 proposed by the IETF aims at providing mobility support on the next generation Internet. First, the authors described the basic principle of mobile IPv6 in brief and analyzed the advantages and disadvantages of it, presented a new idea of allocating a specific address space for mobile node (MN) and developed a new extension header and two ICMP message types for mobile IPv6. Lastly the authors proposed an optimization strategy for mobile IPv6 based on these extensions of protocol, which has the following advantages: 1) It is more convenient to manage the MNs because MN can be judged from its IP address; 2. When the correspondent node (CN) is not actively communicating with a MN, the MN and its home agent (HA) need not send Binding Update to the CN, and the CN need not send Binding Request to the MN. Only when the CN really wants to send a packet to the MN, will the CN voluntarily send a MN Discovery Request message to acquire the MN′s care of address. In this way,the transmission of Binding Update and Binding Request is greatly reduced, consequently the network overhead is also decreased; 3) While sending packets, the CN simply uses a MN Home Address Extension Header without using IPinIP encapsulation and routing header, which can reduce the redundant information in the packet and the message delay; 4) All the packets sent by the CN can be directly routed to the MN and the triangle routing can be completely avoided. By using these protocol extensions, the overhead of the network is greatly reduced and the network quality of services (QoS) is improved.

关键词： mobile IP home agent mobile node care of address binding

Determination of thermal conductivity of magnesium-alloys

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Journal of Central South University of Technology 2001年第1期8卷 60-63页

作者： ZHOU Jie min 1,YANG Ying 1,Magne Lamvik 2.WANG Gang 1 (1.department of Applied Physics and Heat engineering, Central South University, {2. 410083, china 2.Norwegian University of science and Technology) department of Applied Physics and Heat engineering Central South University Changsha China Norwegian University of science and Technology China

An indirect method, Angstroms method was adopted and an instrument was designed to determine the thermal conductivity of magnesium metal and alloys. Angstroms method is an axial periodic heat flow technique by which the thermal diffusivity can be measured directly. Then thermal conductivity can be obtained with relation to thermal diffusivity. Compared with the recommended data from the literature the fitted values of the thermal diffiusivity correspond with 3%, and the credible probability of the thermal conductivity in the range of 0 450 ℃ is about 95%. The method is applicable in the given temperature range.

关键词： angstroms method thermal conductivity thermal diffusivity magnesium alloy

Review on abort trajectory for manned lunar landing mission

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science china(Technological sciences) 2010年第10期53卷 2691-2698页

作者： XI XiaoNing1, HUANG WenDe2.& WANG Wei2.3 1 College of Mechatronics engineering and Automation, National University of Defense Technology, changsha 410073, {2. 2.College of Aerospace and material engineering, National University of Defense Technology, changsha 410073, {2. 3 School of Surveying and Spatial Information System, University of New South Wales, Sydney, NSW 2.52. Australia College of Mechatronics engineering and Automation National University of Defense Technology Changsha China College of Aerospace and material engineering National University of Defense Technology Changsha China School of Surveying and Spatial Information System University of New South Wales Sydney Australia

Abort trajectory is a passage that ensures the astronauts to return safely to the earth when an emergency occurs. Firstly,the essential elements of mission abort are analyzed entirely based on summarizing the existing studies. Then,abort trajectory requirement and rational selection for different flight phases of typical manned lunar mission are discussed specifically. Considering a trade-off between the two primary constrains of an abort,the return time of flight and energy requirement,a general optimizing method for mission abort is proposed. Finally,some suggestions are given for china’s future manned lunar landing mission.

关键词： manned lunar landing mission abort trajectory design free return trajectory

The Compatibility of Polycarboxylate-Type Superplasticizers with Cement

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Journal of Wuhan University of Technology(materials science) 2005年第3期20卷 95-98页

作者：李崇智 department of Civil engineering Beijing Institute of Civil Engineering and Architecture

Four polycarboxylate- type （ PC ） superplasticizers of different functional groups were used ; their dispersing and retaining behaviors were analyzed through ZETA potential measurement, mini-slump test of cement paste and performance test of concrete. The experimental results show that the dispersing and flow-retaining ability of PC was determined by two factors of anionic groups and nonionic groups ： the density of anionic groups - COO^- or - SO3^- acted on the electronic repulsive force. and the length and proportion of nonionic graft groups of PEO in PC chemical stracture affected the steric effect. The compatibility between PC superplasticizers and cement mainly depended on the type of PEO groups ; furtlwrmore, adding mineral powders is good to the compatibility for high performance concretes （ HPCs ）.

关键词： PC superplasticizers cement compatibility

Effect of bond length and radius on superconducting transition temperature for FeAs-based superconductors

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science china(Physics,Mechanics & Astronomy) 2010年第1期53卷 59-63页

作者： CHEN Ning 1 , LIU Yang 1 , JIA YaKui 1 , QU ShaoPeng 1 , ZHANG WanJie 1 & LI Yang 2.1 School of material science and {2., University of science and Technology Beijing, Beijing 100083, china 2.department of {2. science and materials, University of Puerto Rico at Mayaguez, Mayaguez PR 00681-9044, USA University of science and Technology Beijing School of Material Science and Engineering Beijing China (GRID:grid.69775.3a) (ISNI:***) University of Puerto Rico at Mayaguez Department of Engineering Science and Materials Mayaguez USA (GRID:grid.267044.3) (ISNI:0000 0004 0398 9176)

By comparing the data of lattice parameters of more than 50 new FeAs-based high temperature superconductors in two syetems, the effect of bondlength on superconducting transition temperature (T C ) was found that, for both FeAs superconductor systems with similar ionic radii of cation A, the bond length L As-A between Arsenic atom and its nearest neighbor cation at the A site is in an inverse proportion to T C , i.e. the larger the bond length L As-A , the lower the T C . In addition, we also found a noticeable effect of ionic radius on T C , in which deviation from the tendency line of bond length vs. T C decreases with the increasing ionic radius. Both bond length-T C and ionic radii-T C relations indicate that the interaction of cation A and As ion have significant effect on superconductivity. The analysis on the electronic structure indicates that there exists the proximity of the secondary-outer p-orbit of the cation A and the 4s orbit of the As ion, both in energy space and in real space. Some high frequency individual vibrating modes would be established through exchange coupling on their inner orbits. It is worth of mention that the superconducting condensation is influenced by the interaction between the cation A and the As atoms.

关键词： lattice constant FeAs-based superconductor superconducting transition temperature

Piezoelectric transmission spectroelectrochemistry with a normal piezoelectric quartz crystal as an optically-transparent electrode

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Chinese Journal of Chemistry 1994年第5期12卷 425-431页

作者： XIE, Qing-Ji PANG, Xiao-Yong NIE, Li-Hua YAO, Shou-Zhuo department of Chemistry and Chemical engineering, Hunan University, {2., Hunan 410082. china department of Chemistry and Chemical engineering Hunan University Changsha Hunan 410082 China

Piezoelectric transmission spectroelectrochemistry (PTSEC), i.e., the combination of electrochemistry and spectroelectrochemistry (SEC) with electrochemical quartz crystal microbalance (EQCM) technique is reported by using a normal piezoelectric quartz crystal (PQC) as an optically-transparent electrode (OTE). A theoretical relationship between the PQC response and the spectroelectrochemical response is derived and used to estimate the apparent molar absorptivity of the absorbing species deposited on the OTE on the PQC surface. The complex of copper with aspartic acid is used to test this new PQC-SEC technique. Results show that the combination of three such diverse techniques provides a very useful methodology for studying electrode processes and electrode surface characteristics in situ.

关键词： Piezoelectronic transimission spectroelectrochemistry optically-transparent electrode electrochemical quartz crystal microbalance copper aspartic acid.

Research on Cooling Effect with Coolant Groove Structure Parameters in Platelet Transpiration Cooled Nosetip

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Journal of Thermal science 2010年第5期19卷 438-444页

作者： RONG Yisheng and LIU Weiqiang College of Aerospace and material engineering,National Univ.of Defense Technology,{2. 410073,china College of Aerospace and material engineering National Univ. of Defense Technology Changsha China

A platelet transpiration cooled nosetip is considered as thermal protection system （TPS） to prevent hypersonic ve- hicle from the serious aerodynamic heating. Based on the one dimensional flow model, a distribution model of coolant is proposed for the temperature calculation. When Si = Sj （i, j=1,… 2.）, the first cooling effect parameter Pmax is proposed and its relationship with total mass flux and Sc0/Si is investigated. The result shows that Pmax increases while the total mass flux increases, and when the mass flux is fixed, Pmax increases rapidly at the be- ginning and then turns to a nearly stable value while Sc0/Si increases. Then under the precondition of cooling ef- fect, we fix Sc0/Si to insure there is enough space for the pipe. Numerical investigation shows the design of the nosetip makes the transpiration cooling extremely effective. In order to reduce the temperature difference on the nosetip, the second cooling effect parameter Pdiff is proposed and different Pdiff with different 0gi （i=1,..., 2.） are analyzed. According to the cases we design, Pdiff decreases while the upstream 0gi decreases or the down- stream 0gi increases. The best result among cases shows Pdiff is reduced by 15.1%.

关键词： platelet transpiration cooling nosetip thermal protection system aerodynamic heating

Electronic structures and properties of Ti, Zr and Hf metals

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Journal of Central South University of Technology 2001年第2期8卷 83-88页

作者： XIE You qing,PENG Kun,YANG Xin xin (department of materials {2. and engineering, Central South University, changsha 410083, china) department of materials {2. and engineering Central South University Changsha China

The electronic structures of pure Ti, Zr and Hf metals with hcp structure were determined by one atom (OA) theory. According to the electronic structures of these metals,their potential curves, cohesive energies, lattice constants, elasticities and the temperature dependence of linear thermal expansion coefficients were calculated. The electronic structures and characteristic properties of these metals with bcc and fcc structures and liquids were also studied. The results show that the electronic structures of Ti, Zr and Hf metals are respectively [Ar](3d n) 0.481 0 (3d c) 2.085 7 (4s c) 1.000 0 (4s f) 0.433 3 , [Kr](4d n) 0.396 8 (4d c) 2.142.8 (5s c) 1.2.2.0 (5s f) 0.198 4 , [Xe](5d n) 0.368 0 (5d c) 2.041 4 (6s c) 1.406 6 (6s f) 0.184 0 . It is explained why the pure Ti, Zr and Hf metals with hcp and bcc structures can exist naturally, while those with fcc structure can not.

关键词： electronic structure Ti Zr Hf lattice constant cohesive energy crystal structure

Estimation of wall parameters based on range profiles

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science china(Information sciences) 2011年第10期54卷 2178-2189页

作者： LI Xin 1 ,AN DaoXiang 1,HUANG XiaoTao 1 & PENG ShiRui 2.1 College of Electronic science and engineering,National Uniersity of Defense Technology,{2. 410073,china 2.department of Information Counter Measurement Airforce Radar Academy,Wuhan 430019,china College of Electronic science and engineering National University of Defense Technology

Compensation of wall effects is of main concern in SAR through-wall *** parameters are essential for the compensation,which are normally not known a priori.A model of SAR working in sidelooking strip mode for through-wall imaging is established,with the path of signal due to refraction taken into *** analyzing the echo configuration in time domain,a new procedure for estimating wall parameters using high range resolution profiles is *** extracting time delay of target counterpart,the thickness and permittivity of wall are figured out exactly by employing numerical equation method and intersecting of searching *** the estimated parameters,focused image of targets in a room is acquired after wall effects are compensated in imaging processing with back projection *** results verify the validity of the theoretical analysis and imaging algorithm.

关键词： synthetic aperture radar (SAR) range profiles parameters estimation wall compensation