检索结果-南通市图书馆

Dynamic damage and stress-strain relations of ultra-high performance cementitious composites subjected to repeated impact

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2010年第6期53卷 1520-1525页

作者： LAI JianZhong1 & SUN Wei2.1 Department of Materials science and Engineering,nanjing {2. of science and Technology,nanjing 2.0094,china 2.College of Materials science and Engineering,southeast university,nanjing 2.1189,china 1. Department of Materials science and Engineering Nanjing University of Science and Technology Nanjing 210094 China2. College of Materials Science and Engineering Southeast University Nanjing 211189 China

Ultra-high performance cementitious composites (UHPCC) were prepared by replacing 60% of cement with ultra-fine industrial waste *** dynamic damage and compressive stress-strain relations of UHPCC were studied using split Hopkinson pressure bar (SHPB).The damage of UHPCC subjected to repeated impact was measured by the ultrasonic pulse velocity *** show that the dynamic damage of UHPCC increases linearly with impact times and the abilities of repeated impact resistance of UHPCC are improved with increasing fiber volume *** stress waves on impact were recorded and the average stress,strain and strain rate of UHPCC were calculated based on the wave propagation *** effects of strain rate,fibers volume fraction and impact times on the stress-strain relations of UHPCC were *** show that the peak stress and elastic modulus decrease while the strain rate and peak strain increase gradually with increasing impact times.

关键词： ultra-high performance cementitious composites (UHPCC) split Hopkinson pressure bar (SHPB) repeated impact damage stress-strain

Effect of Excipients on Stability and Structure of rhCuZn-SOD Encapsulated in PLGA Microspheres

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2004年第3期20卷 323-327页

作者： LIU Ling 1,2.,GE Yu 1 and YUAN Qin-sheng 1 1. State Key Laboratory of Bioreactor Engineering and Institute of Biochemistry,East china university of {2. and Technology,Shanghai 2.02.7,P. R. china 2. Public Health School,nanjing medical university,nanjing 2.002.,P. R. china E china Univ Sci & Technol State Key Lab Bioreactor Engn Shanghai 200237 Peoples R China E china Univ Sci & Technol Inst Biochem Shanghai 200237 Peoples R China nanjing Med Univ Sch Publ Hlth Nanjing 210029 Peoples R China

When a protein is encapsulated into poly( DL -lactide-co-glycolide)(PLGA) microspheres by means of the double-emulsion method,the harsh microspheres formation process including ultrasonification,exposure to an organic solvent and a polymer may cause the denaturation of the protein. In this study,we investigated the enzymatic activity change and the effect of the excipients on the stability of recombinant human Cu,Zn-superoxide dismutase(rhCu,Zn-SOD) during the emulsification. The specific activity recovery was found to be concentration dependent and the excipients involved such as PEG 600 and Tween 2.,and trehalose were shown to increase the stability of rhCu,Zn-SOD. The protein structural integrity within the microspheres was analyzed by FTIR. The structure of rhCu,Zn-SOD within PLGA microspheres containing trehalose was found to be similar to that of the native solid state,whereas the protein encapsulated during the preparation in the absence of any excipient changed due to the possible hydrophobic interaction with the polymer. The results suggest that a rational stability strategy for protein to be encapsulated into microspheres should aim at different processes.

关键词： Poly( DL -lactide-co-glycolide)(PLGA) microsphere Recombinant human Cu Zn-superoxide dismutase(rhCu Zn-SOD) Fourier transform infrared(FTIR) spectroscopy Protein stability Excipient

MMSE relay precoding schemes based on quantization error compensation for multi-relay system

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2010年第12期53卷 2548-2556页

作者： LI Ting 1,2.& YANG LuXi 2.1 College of Communication and Information Engineering,nanjing university of Posts and Telecommunications,nanjing 2.0003,china 2.School of Information science and Engineering,southeast university,nanjing 2.0096,china 1. College of Communication and Information Engineering Nanjing University of Posts and Telecommunications Nanjing 210003 China2. School of Information Science and Engineering Southeast University Nanjing 210096 China

In order to deal with the performance degradation resulting from the quantization error,this paper introduces the statistics of Grassmannian codebook's quantization error into relay precoding design for multirelay *** on the two-step MMSE optimization algorithm for relay precoding and receiver equalizing with full feedback under QoS requirements,we first propose a limited feedback two-step MMSE optimization scheme for relay precoding and receiver equalizing with quantization error compensation,and then we propose a limited feedback joint MMSE optimization scheme for relay precoding and receiver equalizing with quantization error compensation subject to a global power constraint at the output of *** results show that the proposed joint MMSE optimization scheme with quantization error compensation has a much lower bit-error rate than the two-step MMSE optimization scheme with quantization error compensation and the joint MMSE optimization scheme without quantization error compensation.

关键词： multi-relay precoding limited feedback minimum mean square error

Study on the thermal stability and electrical properties of the high-k dielectrics (ZrO_2. _x(SiO_2._(1-x)

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Technological sciences) 2009年第8期52卷 2222-2226页

作者： Lü ShiCheng1,2. YIN Jiang1,2. XIA YiDong2.3, GAO LiGang2.3 & LIU ZhiGuo2.3 1 Department of Physics, nanjing university, nanjing 2.0093, china 2.National Laboratory of Solid Sate Microstructures, nanjing university, nanjing 2.0093, china 3 Department of Materials science and Engineering, nanjing university, nanjing 2.0093, china 1. Department of Physics Nanjing University Nanjing 210093 China 2. National Laboratory of Solid Sate Microstructures Nanjing University Nanjing 210093 China 3. Department of Materials science and Engineering Nanjing University Nanjing 210093 China

(ZrO2.x(SiO2.1-x (Zr-Si-O) films with different compositions were deposited on p-Si(100) substrates by using pulsed laser deposition technique. X-ray photoelectron spectra (XPS) showed that these films remained amorphous after annealing at 800℃ with RTA process in N2.for 60 s. The XPS spectra indi- cated that Zr-Si-O films with x=0.5 suffered no obvious phase separation after annealing at 800℃, and no interface layer was formed between Zr-Si-O film and Si substrate. While Zr-Si-O films with x >0.5 suffered phase separation to precipitate ZrO2.after annealing under the same condition, and SiO2.was formed at the interface. To get a good interface between Zr-Si-O films and Si substrate, Zr-Si-O films with bi-layer structure (ZrO2.0.7(SiO2.0.3/(ZrO2.0.5(SiO2.0.5/Si was deposited. The electrical properties showed that the bi-layer Zr-Si-O film is of the lowest equivalent oxide thickness and good interface with Si substrate.

关键词： high-k dielectric film pulsed laser deposition pseudo ternary alloy

Dynamic Mechanical Behaviour of Ultra-high Performance Fiber Reinforced Concretes

在线全文

学校读者我要写书评

暂无评论

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 science & 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

Study on impurity desorption induced by femtosecond pulse laser based on a stochastic process model

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2006年第1期49卷 78-88页

作者： CHI Yinsheng1, LIN Xiaohui1, ZHUANG Ping1 & CHEN Yunfei1,2.1. Department of Mechanical Engineering, southeast university, nanjing 2.0096, {2. 2. Key Laboratory of MEMS of {2. Educational Ministry, southeast university, nanjing 2.0096, {2. Department of Mechanical Engineering Southeast University Nanjing 210096 China Key Laboratory of MEMS of china Educational Ministry Southeast University Nanjing 210096 China

With the advantages on non-equilibrium heating and desorption induced by electronic transition, the femtosecond pulse laser introduces a new way for solving the problem of impurity pollution adsorbed on a solid thin film in micro-electro-mechanical systems (MEMS). A model based on stochastic processes was established for stimulated desorption induced by the femtosecond pulse laser to interpret the interaction of the opti-cally excited hot electrons with the adsorbed molecules in a metal substrate. Numerical simulation results reveal a time-dependent desorption probability of adsorbed molecules and indicate that how key parameters of femtosecond pulse laser, such as incident laser energy flux, pulse duration, and wavelength of pulse, have a great effect on the desorption probability.

关键词： desorption, femtosecond pulse laser, stochastic process.

Restrictive mechanism of flow control among non-cooperative Internet users

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2011年第1期54卷 12-22页

作者： TAO Jun1,2.ZHONG Xiao1,2.& LU YiFei1,2.1Key Laboratory of Computer Network and Information Integration,southeast university, Ministry of Education,nanjing 2.0096,{2. 2.chool of Computer science and Engineering,southeast university,nanjing 2.0096,{2. 1. Key Laboratory of Computer Network and Information Integration Southeast University Ministry of Education Nanjing 210096 China2. School of Computer Science and Engineering Southeast University Nanjing 210096 China

The flow and congestion control methods based on one-shot game model with non-cooperative game theory can explain the non-cooperative behavior of Internet ***,the low effciency of equilibrium solutions affects their *** the behavior of flow and congestion control based on infinitely repeated game models is addressed;the repeated and infinitely repeated flow and congestion control game model is presented; the existence and optimization of the Nash equilibrium point are proved;the discount factor in repeated game is discussed;the punishment and threat strategy to users'misbehavior is studied in N-users infinitely flow control game;the punishment restrictive method of users'behavior is designed in infinitely and finitely games;finally,a flow control algorithm based on repeated game,FCAR,is provided based on the conclusions of repeated game *** results of experiment and simulation show that FCAR algorithm could regularize and restrict users' misbehavior *** algorithm can also make non-cooperative Internet users achieve cooperation in order to optimize the utility of the whole flow and congestion control system.

关键词： Nash equilibrium utility infinitely and finitely repeated game flow and congestion control

Cross-linked Polyethylenimine as Potential DNA Vector for Gene Delivery with High Efficiency and Low Cytotoxicity

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2006年第11期38卷 780-787页

作者： Wei DONG~(1,2. Guang-Hui JIN~1 Shu-Feng LI~(1,3) Qi-Ming SUN~1 Ding-Yuan MA~1 Zi-Chun HUA~1 1 State Key Laboratory of Pharmaceutical Biotechnology,College of Life science,nanjing {2.,nanjing 2.0093,china 2.School of Chemical Engineering nanjing {2. of science and Technology,nanjing 2.0094,china 3 College of basic medical science,southeast university,nanjing 2.0009,china StateKeyLaboratoryofPharmaceuticalBiotechnology CollegeofLifeScienceNanjingUniversityNanjing210093China SchoolofChemicalEngineering NanjingUniversityofScienceandTechnologyNanjing210094China

Polyethylenimine (PEI) has been known as an efficient gene carrier with the highest cationiccharge *** transfection efficiency of PEI,along with its cytotoxicity,strongly depends on itsmolecular *** enhance its gene delivery efficiency and minimize cytotoxicity,we have synthesizedsmall cross-linked PEI with biodegradable linkages and evaluated their transfection efficiencies in *** study,branched PEI with a molecular weight of 800 Da was cross-linked by small diacrylate[1,4-butanediol diacrylate or ethyleneglycol dimethacrylate (EGDMA)] for 2.6 *** efficiencies of thecross-linked PEI in in vitro transfection of plasmid DNA containing enhanced green fluorescent protein(EGFP) reporter gene were assessed in melanoma B 16F10 cell line and other cell *** cytometrywas used to quantify the cellular entry efficiency of plasmid and the transgene expression *** of the cross-linked PEI in these cells were evaluated by MTT ***-PEI 800-4h,atypical cross-linked PEI reported here,mediated a more efficient expression of reporter gene than thecommercially available 2.-kDa branched PEI control,and resulted in a 9-fold increase in gene deliveryin B16F10 cells and a 16-fold increase in 2.3T cells,while no cytotoxicity was found at the optimizedcondition for gene ***,the transfection activity of polyplexes was preserved in thepresence of serum proteins.

关键词： polyethylenimine gene delivery cytotoxicity B16F10 2.3T cell line

SrGa_2._4∶Ce blue TFEL in new structure

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese science Bulletin 1998年第7期43卷 603-605页

作者： XU Chunxiang+1, LOU Zhidong+2. XU Zheng+3 and XU Xurong+31. National Laboratory of Molecular and Biomolecular Electronics, southeast university, nanjing 2.0096, {2. 2. Department of Applied Physics, Tianjin university, Tianjin 300031, {2. 3. Institu National Laboratory of Molecular and Biomolecular Electronics Southeast University Nanjina China Department of Applied Physics Tianjin University Tianjin China Institute of Photoelectronic Technology Northern Jiaotong University Beijing China

SrGa-2.-4∶Ce blue TFEL device with a novel structure was prepared by electron beam evaporation. The dielectric constant of insulator layer in this structure is far less than that in the conventional structure, so the hot-electrons can be accelerated in SiO-2.layers. The stable TFEL with good chromaticity was achieved and the basic characteristics were investigated.

关键词： SrGa-2.-4∶Ce bule TFEL low dielectric constant insulator layer.