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Granular Effect of Fly Ash Repairs Damage of Recycled Coarse Aggregate

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Journal of Shanghai Jiaotong university(science) 2008年第2期13卷 177-180页

作者：李九苏肖汉宁龚建清 College of materials science and {2. Hunan University changsha University of science & Technology Changsha 410076China

Repairing effect of fly ash （FA） on damage of recycled coarse aggregate was evaluated by characteristics of pores and cracks in the vicinity of interracial transition zone （ITZ）. The interracial structure between the virgin aggregate and the attached old mortar was investigated and compared with ITZ of recycled aggregate concrete in the presence of FA or ultra-fine FA（UFA） by means of scanning electron microscope （SEM）. Diameter and plumpness frequency distribution of pores as well as width of the old ITZ, length of contacting points and cracks density were analyzed. The SEM results reveal that the diameter of pores is decreases significantly but pores plumpness increases. A decreased ITZ width and cracks density as well as an increased bonding zone length can also been observed, which indicates that FA or UFA repairs damage of recycled coarse aggregate due to its granular effect.

关键词： pores structure characteristics of interfaciial transition zone fly ash repairing effect

1,2.环己二醇二缩水甘油醚合成反应过程模拟

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石油化工 2005年第1期34卷 46-50页

作者：袁剑民邓剑如湖南大学料学院湖南大学化工学院湖南长沙410082

在三氟化硼-乙醚催化作用下,1,2.环己二醇(CHD)与环氧氯丙烷(ECH)发生醚化反应,加碱闭环脱去氯化氢得到1,2.环己二醇二缩水甘油醚。在对此合成反应过程分析的基础上,通过合理的假设,运用数学模型的方法对反应过程进行了模拟计算,建立了... 详细信息

在三氟化硼-乙醚催化作用下,1,2.环己二醇(CHD)与环氧氯丙烷(ECH)发生醚化反应,加碱闭环脱去氯化氢得到1,2.环己二醇二缩水甘油醚。在对此合成反应过程分析的基础上,通过合理的假设,运用数学模型的方法对反应过程进行了模拟计算,建立了相应的数学模型。利用该模型可以从原料CHD,ECH和三氟化硼-乙醚的配比预测产物的环氧值。实验验证表明,该模型模拟计算得到的最高环氧值(0.607mol/100g)与实验值(0.595mol/100g)接近。

关键词： 1,2.环己二醇环氧氯丙烷环氧值数学模型 1,2.环己二醇二缩水甘油醚

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) 1. department of Applied Physics and Heat engineering Central South University 410083 Changsha China 2. 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

Dynamic Mechanical Behaviour of Ultra-high Performance Fiber Reinforced Concretes

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Journal of Wuhan University of Technology(materials science) 2008年第6期23卷 938-945页

作者：赖建中 department of materials {2. & engineering Nanjing University of Science & Technology

Ultra-high performance fiber reinforced concretes （UHPFRC） were prepared by replacing 60% of cement with ultra-fine industrial waste powder. The dynamic mechanical behaviour of UHPFRC with different fiber volume fraction was researched on repeated compressive impact in four kinds of impact modes through split Hopkinson pressure bar （SHPB）. The experimental results show that the peak stress and elastic modulus decrease and the strain rate and peak strain increase gradually with the increasing of impact times. The initial material damage increases and the peak stress of the specimen decreases from the second impact with the increasing of the initial incident wave. Standard strength on repeated impact is defined to compare the ability of resistance against repeated impact among different materials. The rate of reduction of standard strength is decreased by fiber reinforcement under repeated impact. The material damage is reduced and the ability of repeated impact resistance of UHPFRC is improved with the increasing of fiber volume fraction.

关键词： ultra-high performance fiber reinforced concretes split Hopkinson pressurebar dynamic repeated impact

Numerical study on the characteristics of flow field and wave propagation near submerged breakwater on slope

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Acta Oceanologica Sinica 2010年第1期29卷 88-99页

作者： CHEN Jie JIANG Changbo HU Shixiong HUANG Wenwei School of Hydraulic engineering Changsha University of Science ＆ Technology Changsha 410114 China hunan Province Key Laboratory of Water Sediment Sciences ＆ Flood Hazard Prevention Changsha 410114 China department of Geography East Stroudsburg University of Pennsylvania East Stroudsburg PA 18301 USA School of Foreign Languages Changsha University of Science ＆ Technology Changsha 410114 China

In this study, characteristics of flow field and wave propagation near submerged breakwater on a sloping bed are investigated with numerical model. The governing equations of the vertical two-dimensional model are Reynolds Averaged Navier Stokes equations. The Reynolds stress terms are closed by a nonlinear k - ε turbulence transportation model. The free surface is traced through the PILC-VOF method. The proposed numerical model is verified with experimental results. The numerical result shows that the wave profile may become more asymmetrical when wave propagates over breakwater. When wave crest propagates over breakwater, the anticlockwise vortex may generate. On the contrary, when wave hollow propagates over breakwater, the clockwise vortex may generate. Meanwhile, the influenced zone of vortex created by wave crest is larger than that created by wave hollow. All the maximum values of the turbulent kinetic energy, turbulent dissipation and eddy viscosity occur on the top of breakwater. Both the turbulent dissipation and eddy viscosity increase as the turbulent kinetic energy increases. Wave energy may rapidly decrease near the breakwater because turbulent dissipation increases and energy in lower harmonics is transferred into higher harmonics.

关键词： submerged breakwater characteristics of flow field PLIC-VOF method sloping bed

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 1. College of Information science and engineering Central South University 410083 Changsha China 2. department of Physics and Electronic engineering Jishou University 416000 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

Preparation, characterization, viscosity and thermal conductivity of CaCO_3 aqueous nanofluids

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science china(Technological sciences) 2010年第2期53卷 360-368页

作者： ZHU HaiTao1, LI ChangJiang2. WU DaXiong1, ZHANG CanYing1 & YIN YanSheng2.1 College of materials science and {2., Qingdao University of science and Technology, Qingdao 2.6042. china 2.department of materials, Ocean University of china, Qingdao 2.6003, china 1. College of materials science and {2. Qingdao University of Science and Technology Qingdao 266042 China2. Department of Materials Ocean University of China Qingdao 266003 China

CaCO3 aqueous nanofluids were prepared by dispensing aqueous CaCO3 paste into distilled water under ultrasonic vibration. The actual microstructures of the CaCO3 nanofluids with different particle volume fractions were characterized by freeze etching replication transmission electron microscopy (FERTEM). Thermal conductivity and rheological behavior of the nanofluids were measured by standard analyzers. The results show that CaCO3 paste as raw material for nanofluids is advantageous to reducing aggregation of primary nanoparticles. The effective viscosities and effective thermal conductivities of the CaCO3 nanofluids are related to the aggregates of nanoparticles and can be well predicted by the modified Krieger & Dougherty formula and the modified Hamilton & Crosser model, respectively.

关键词： CaCO3 nanofluid thermal conductivity viscosity microstructure

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 1. College of Mechatronics engineering and Automation National University of Defense Technology Changsha 410073 China2. College of Aerospace and Material Engineering National University of Defense Technology Changsha 410073 China3. School of Surveying and Spatial Information System University of New South Wales Sydney NSW 2052 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

A new navigation approach of terrain contour matching based on 3-D terrain reconstruction from onboard image sequence

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science china(Technological sciences) 2010年第5期53卷 1176-1183页

作者： LI LiChun1,2.YU QiFeng2.SHANG Yang2.YUAN Yun2.LU HongWei3 & LIU XiaoLin4 1 Beijing Aerospace Control Center,Beijing 100094,china 2.College of Aerospace and material {2.,National University of Defense Technology,changsha 410073,china 3 Equipment Research Institute of PLA’s Second Artillery,Beijing 100085,china 4 College of Mechatronic {2. and Automation,National University of Defense Technology,changsha 410073,china 1. Beijing Aerospace Control Center Beijing 100094 China2. College of Aerospace and Material Engineering National University of Defense Technology Changsha 410073 China3. Equipment Research Institute of PLA’s Second Artillery Beijing 100085 China4. College of Mechatronic Engineering and Automation National University of Defense Technology Changsha 410073 China

This article presents a passive navigation method of terrain contour matching by reconstructing the 3-D terrain from the image sequence(acquired by the onboard camera).To achieve automation and simultaneity of the image sequence processing for navigation,a correspondence registration method based on control points tracking is proposed which tracks the sparse control points through the whole image sequence and uses them as correspondence in the relation geometry ***,a key frame selection method based on the images overlapping ratio and intersecting angles is explored,thereafter the requirement for the camera system configuration is *** proposed method also includes an optimal local homography estimating algorithm according to the control points,which helps correctly predict points to be matched and their speed ***,the real-time 3-D terrain of the trajectory thus reconstructed is matched with the referenced terrain map,and the result of which provides navigating *** digital simulation experiment and the real image based experiment have verified the proposed method.

关键词： terrain contour matching vision-based navigation 3-D reconstruction control points key frame registration optimal local homography