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Effects of chitosan/collagen substrates on the behavior of rat neural stem cells

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Science china(Life Sciences) 2010年第2期53卷 215-222页

作者： YANG ZhaoYang1,MO LinHong2,DUAN HongMei2 & Li XiaoGuang1,2 1 school of Biological Science and medical engineering,Beihang university,beijing 100191,china 2 beijing institute for Neuroscience,Capital medical university,beijing 100069,china school of Biological Science and medical engineering Beihang University Beijing China beijing institute for Neuroscience Capital Medical University Beijing China

Spinal cord and brain injuries usually lead to cavity *** transplantation by combining stem cells and tissue engineering scaffolds has the potential to fill the cavities and replace the lost neural *** chitosan and collagen have their unique *** this study,the effects of chitosan and collagen on the behavior of rat neural stem cells (at the neurosphere level) were tested in vitro in terms of cytotoxicity and supporting ability for stem cell survival,proliferation and *** the serum-free condition,both chitosan membranes and collagen gels had low cytotoxicity to *** is,cells migrated from neurospheres,and processes extended out from these neurospheres and the differentiated *** with the above two materials,chitosan-collagen membranes were more suitable for the co-culture with rat neural stem cells,because,except for low cytotoxicity and supporting ability for the cell survival,in this group,a large number of cells were observed to migrate out from neurospheres,and the differentiating percentage from neurospheres into neurons was significantly *** modification of chitosan-collagen membranes may shed light on in vivo nerve regeneration by transplanting neural stem cells.

关键词： chitosan collagen neural stem cells biocompatibility differentiation

A generalized mean shift tracking algorithm

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Science china(Information Sciences) 2011年第11期54卷 2373-2385页

作者： CHEN JianJun 1,4,ZHANG SuoFei 1,AN GuoCheng 2 & WU ZhenYang 1,31 school of Information Science and engineering,Southeast university,Nanjing 210096,china 2 Intelligence engineering Lab,institute of Software Chinese Academy of Sciences,beijing 100190,china 3 Key Laboratory of Underwater Acoustic Signal Processing of Ministry of Education,Southeast university,Nanjing 210096,china 4 Nanjing research institute of Electronic Technology,Nanjing 210013,china school of Information Science and engineering Southeast University Nanjing China Nanjing research institute of Electronic Technology Nanjing China Intelligence engineering Lab Institute of Software Chinese Academy of Sciences Beijing China Key Laboratory of Underwater Acoustic Signal Processing of Ministry of Education Southeast University Nanjing China

CAMSHIFT algorithm and Comaniciu/Meer algorithm are two fundamental frameworks of mean shift procedure for video target *** paper generalizes the two well-known mean shift tracking algorithms,originally due to Bradski and Comaniciu/Meer.A new general similarity function which defines the distance between the target model and target candidate is employed to calculate the pixel weights and the target *** target size is iteratively estimated and updated based on the zeroth order moment of the pixel *** we prove that both the CAMSHIFT algorithm and the Comaniciu/Meer algorithm can be included in the generalized mean shift tracking *** tracking performances of three mean shift algorithms in the unified framework are shown and compared in the experimental results.

关键词： mean shift CAMSHIFT video target tracking similarity measure

The precipitation strengthening behavior of Cu-rich phase in Nb contained advanced Fe-Cr-Ni type austenitic heat resistant steel for USC power plant application

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Progress in Natural Science:Materials International 2012年第3期22卷 175-185页

作者： Cheng-yu Chi a, Hong-yao Yu b, Jian-xin Dong b, Wen-qing Liu c, Shi-chang Cheng d, Zheng-dong Liu d, Xi-shan Xie b a school of Metallurgical and Ecological engineering, university of Science & Technology beijing, beijing 100083, china b school of Materials Science and engineering, university of Science & Technology beijing, beijing 100083, china c Instrumental Analysis & research Center, Shanghai university, Shanghai 200444, china d Central Iron and Steel research institute, beijing 100081, china school of Metallurgical and Ecological engineering University of Science & Technology Beijing Beijing 100083 China school of Materials Science and engineering University of Science & Technology Beijing Beijing 100083 China Instrumental Analysis & research Center Shanghai University Shanghai 200444 China Central Iron and Steel research institute Beijing 100081 China

Copper has been used as a strengthening element in newly developed Fe-Cr-Ni type austenitic heat resistant steel for inducing Cu-rich phase precipitation to meet high temperature strength requirement for 600 ℃ Ultra Super-Critical (USC) coal fired power plants for many years. However, the precipitation behavior and strengthening mechanism of Cu-rich phase in these advanced austenitic heat resistant steels is still unclear. In order to understand the precipitation strengthening behavior of Cu-rich phase and to promote high strength austenitic heat resistant steel development, 18 Cr9 NiCuNb steel which is a Cu-added Nb contained advanced Fe-Cr-Ni type austenitic heat resistant steel has been selected for this study to be aged at 650 ℃ till to 10,000 h. Micro-hardness and room temperature tensile test were conducted after long-time aging. SEM, TEM, HRTEM and three dimensional atom probe (3DAP) technology accompanying with thermodynamic calculation have been used to investigate the Cu-rich phase precipitation behavior during 650 ℃ aging. The experimental results showed that Cu atoms can quickly concentrate in clusters at very early precipitation stage to form the fine nano-size Cu-rich "segregation areas" within less than 1 h at 650 ℃. With increasing aging time at 650 ℃ Cu atoms continuously concentrate to Cu-rich segregation areas (clusters) and simultaneously other kinds of atoms such as Fe, Cr and Ni diffuse away from Cu-rich segregation areas to austenitic matrix, and finally to complete the transformation from Cu-rich segregation areas to Cu-rich phase. However, there is only Cu atoms concentration but not crystallographic transformation from early stage of Cu-rich clusters forming to the final Cu-rich phase formation. Even the Cu atom becomes the main composed element after 500 h aging at 650 ℃ the Cu-rich phase still keeps coherent relationship with austenitic matrix. According the experimental results in this study, Cu-rich phase precipitation sequence which st

关键词： USC power plant Austenitic heat resistant steel Microstructure Cu-rich phase TEM 3DAP

Study on Transformation of CaO-Al_2O_3-SiO_2-MgO System Inclusions in ZG06Cr13Ni4Mo Stainless Steel

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Journal of Iron and Steel research International 2011年第S2期18卷 341-346页

作者： LIU Jian-hui1,3, DONG Han1,3, ZHU Rong2, LI Shi-qi2 (1. institute for Structural Materials,Central Iron and Steel research institute, beijing 100081,china 2. school of Metallurgical and Ecological engineering,university of Science and Technology beijing, beijing 100083,china 3. National engineering research Center of Advanced Steel Technology, beijing 100081,china) Cent Iron & Steel Res Inst Inst Struct Mat Beijing 100081 Peoples R China Natl Engn Res Ctr Adv Steel Technol Beijing 100081 Peoples R China Univ Sci & Technol beijing Sch Met & Ecol Engn Beijing 100083 Peoples R China

This paper aims at generally studying on the inclusions of ZGG06Cr13Ni4Mo ultra-low carbon stainless steel used for large scale hydraulic turbine sets. On the basis of analysis the industrial test samples, thermodynamic software FactSage is used to study inclusions transformation process in CaO-SiO2-Al2O3-MgO system while stainless steel is been smelting. The results illustrate the inclusions melting points and plasticity variation law. The reasonable inclusions plasticity controlling area is found out in low melting point. The melting point is up to 1280℃ While MgO weight concentration is 10% in CaO-SiO2-Al2O3-MgO system, SiO2, Al2O3 and CaO in inclusions are in weight concentration range of 50-70%, 10-20% and 10-40%, respectively. For purpose of gaining low melting point inclusions, silicon alumina radio in deoxidant should be controlled between 2-5 for ultra-low carbon stainless steel refining in industry.

关键词： ZG06Cr13Ni4Mo stainless steel low melting point inclusion thermodynamic calculation

Numerical simulation of profile control by clay particles after polymer flooding

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Petroleum Science 2010年第4期7卷 509-514页

作者： Feng Qihong Shi Shubin Wang Sen Zheng Lu school of Petroleum engineering China University of Petroleum Qingdao Shandong 266555 China school of Petroleum engineering China University of Petroleum Beijing 102249 China Shengli Oil Production research institute SINOPEC Dongying Shandong 257000 China Bozhong Operation Company CNOOC Tianjin 300452 China

A three-dimensional,two-phase,five-component mathematical model has been developed to describe flow characteristics of clay particles and flocs in the profile control process,in which the clay particle suspension is injected into the formation to react with residual *** model considers the reaction of clay particles with residual polymer,apparent viscosity of the mixture,retention of clay particles and flocs,as well as the decline in porosity and permeability caused by the retention of clay particles and flocs.A finite difference method is used to discretize the equation for each component in the *** Runge-Kutta method is used to solve the polymer flow equation,and operator splitting algorithms are used to split the flow equation for clay particles into a hyperbolic equation for convection and a parabolic equation for diffusion,which effectively ensures excellent precision,high speed and good *** numerical simulation had been applied successfully in the 4-P1920 unit of the Lamadian Oilfield to forecast the blocking capacity of clay particle suspension and to optimize the injection parameters.

关键词： Clay particles flocs detention operator splitting algorithms numerical simulation

Unified solutions for stresses and displacements around circular tunnels using the Unified Strength Theory

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Science china(Technological Sciences) 2010年第6期53卷 1694-1699页

作者： ZHANG ChangGuang1,WANG JiangFeng2 & ZHAO JunHai3 1 Department of Geotechnical engineering,Tongji university,Shanghai 200092,china 2 North china institute of Water Conservancy and Hydroelectric Power,Zhengzhou 450011,china 3 school of Civil engineering,Chang’an university,Xi’an 710061,china Department of Geotechnical engineering Tongji University Shanghai China North china institute of Water Conservancy and Hydroelectric Power Zhengzhou China school of Civil engineering Chang’an University Xi’an China

The unified solutions are presented for stresses and displacements around a circular tunnel subjected to a hydrostatic stress *** rock mass is assumed to be elastic-brittle-plastic and governed by the Unified Strength *** displacements are obtained accounting for three different definitions for elastic strains and different Young's modulus in the plastic *** unified solutions obtained in this paper are especially versatile in reflecting the intermediate principal stress effect to different extents for different *** conventional solutions,based on the Mohr-Coulomb failure criterion and the Generalized Twin Shear Stress yield criterion,are special cases of the present unified *** new unified solutions can compare with those computed by the latest generalized Hoek-Brown failure *** results obtained demonstrate the importance of the intermediate principal stress influence for the stresses and displacements *** effects of different definitions for elastic strains and different Young's modulus in the plastic zone on the displacements are significant.

关键词： Unified Strength Theory intermediate principal stress different definitions for elastic strains different Young’s modulus

Modified HDDR Process for Producing Anisotropic NdFeB Powders

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Journal of university of Science and Technology beijing 2001年第2期8卷 111-114页

作者： Xubo Liu, Yue Ming, Yaofu Xiao, Qi Zeng, Zhengyi Zhang, Run Wang (Material Science and engineering school, university of Science and Technology beijing, beijing 100083, china) (beijing institute of Aeronautical Materials, beijing 100095, china) Material Sci. and engineering school University of Science and Technology Beijing 100083 China

The effect of HDDR (hydrogenation-decomposition-desorption-recombination process) treating conditions on magnetic anisotropy of Nd13FebalCo17B7Ga1Zr0.1 powders has been studied. It is found that increasing recombination temperature is effective for magnetic anisotropy formation, but at the cost of reducing the coercive force. The microstructure analysis (TEM) indicates that the NdFeB recombination nucleation takes place markedly during the transition range from decomposition stage to recombination stage, in which both temperature and H-2 pressure change sharply. In order to create a more stable treatment condition for recombination nucleation, a modified HDDR process is established in which the conventional continuous transition range is divided into several stages. The experimental results have proved that such a process can effectively enhance the remanence of the magnet powders with high certainty, while only cause a little reduction in coercivity.

关键词： HDDR anisotropy NdFeB

Towards a degradation-based mechanism for adaptive overload control

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Science china(Information Sciences) 2012年第12期55卷 2708-2722页

作者： WANG ZiYou 1,2,ZHOU MingHui 1,2 & MEI Hong 1,2 1 Software institute,school of Electronics engineering and Computer Science,peking university,beijing 100871,china 2 Key Laboratory of High Confidence Software Technologies(peking university),Ministry of Education,beijing 100871,china Software institute School of Electronics Engineering and Computer Science Peking University Beijing China Ministry of Education Key Laboratory of High Confidence Software Technologies (Peking University) Beijing China

Uncontrolled overload is one of the major causes of the system's decline in reliability and performance for web *** also harms the construction of trustworthy *** paper presents a degradationbased mechanism to adaptively control overload in complex,dynamic web *** our mechanism,the bottlenecks in the application's performance are determined by internally monitoring the performance and resource utilization state of the application,which is decomposed into a set of *** locating the bottlenecks,two decision algorithms are proposed to dynamically and adaptively generate proper degradation plans without *** degrading the service which consumes critical resources and has a low priority from the perspective of business logic,the application can keep providing key services even when overload *** implement a prototype and conduct a case study on a wiki *** also evaluate our approach and demonstrate its effectiveness in simulated overload *** handling overload,we make a breakthrough in building trustworthy software in an open,dynamic and rapidly changing environment.

关键词： overload service degradation resource monitoring performance management

cDNA Cloning of Two Novel T-superfamily Conotoxins from Conus leopardus

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Acta Biochimica et Biophysica Sinica 2006年第4期38卷 287-291页

作者： Wei-Hua CHEN~(1,2#) Yu-Hong HAN~(2,3#) Qi WANG~(2,3#) Xiao-Wei MIAO~(2,4) Ling OU~1 Xiao-Xia SHAO~2* 1 Bioengineering institute,East china university of Science and Technology,Shanghai 200237,china 2 institute of Protein research,Tongji university,Shanghai 200092,china 3 institute of Biochemistry and Cell Biology,Shanghai institute of Biochemical Sciences,Chinese Academy of Sciences,Shanghai 200031,china 4 Department of Biological engineering,school of Life Science,Shanghai university,Shanghai 200436,china Bioengineering institute East China University of Science and TechnologyShanghai 200237 China institute of Protein research Tongji UniversityShanghai 200092 China institute of Biochemistry and Cell Biology Shanghai Institute of Biochemical Sciences Chinese Academy of SciencesShanghai 200031 China Department of Biological engineering School of Life Science Shanghai UniversityShanghai 200436 China

The full-length cDNAs of two novel T-superfamily conotoxins,Lp5.1 and Lp5.2,were clonedfrom a vermivorous cone snail Conus leopardus using 3'/5'-rapid amplification of cDNA *** cDNA ofLp5.1 encodes a precursor of 65 residues,including a 22-residue signal peptide,a 28-residue propeptide anda 15-residue mature ***5.1 is processed at the common signal site -X-Arg- immediately before themature peptide *** the case of Lp5.2,the precursor includes a 25-residue signal peptide anda 43-residue sequence comprising the propeptide and mature peptide,which is probably cleaved to yield a29-residue propeptide and a 14-residue mature *** these two conotoxins share a similar signalsequence and a conserved disulfide pattern with the known T-superfamily,the pro-region and mature peptidesare of low identity,especially Lp5.2 with an identity as low as 10.7% compared with the reference *** elucidated cDNAs of these two toxins will facilitate a better understanding of the species distribution,the sequence diversity of T-superfamily conotoxins,the special gene structure and the evolution of thesepeptides.

关键词： Conus leopardus T-superfamily conotoxin cDNA cloning