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Science china(Technological Sciences) 2009年第3期52卷 584-589页

作者： XU YePeng1 & ZHOU Ding2 1 School of Science, nanjing university of Science and technology, nanjing 210094, china 2 college of civil engineering, nanjing university of technology, nanjing 210009, china School of Science Nanjing University of Science and Technology Nanjing China college of civil engineering Nanjing University of Technology Nanjing China

This paper studies the bending of simple-supported rectangular plate on point supports, line supports and elastic foundation. On the basis of three-dimensional elasticity theory, the exact expressions of the displacement functions, which satisfy the governing differential equations and the simply supported boundary conditions at four edges of the plate, are analytically derived. The reaction forces of the in- termediate supports are regarded as the unknown external forces acting on the lower surface of the plate. The unknown coefficients are then determined by the boundary conditions on the upper and lower surfaces of the plate. Comparing the numerical results obtained from the proposed method to those obtained from Kirchhoff plate theory, Mindlin plate theory and those obtained from the commer- cial finite element software ANSYS, the high accuracy of the present method has been demonstrated.

关键词： rectangular plate point support line support elastic foundation displacement stress three-dimensional elasticity solution

Three-dimensional elasticity solution of simple-supported rectangular plate on point supports,line supports and elastic foundation

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中国科学:技术科学 2010年第3期 323-323页

This paper studies the bending of simple-supported rectangular plate on point supports,line supports and elastic *** the basis of three-dimensional elasticity theory,the exact expressions of the displacement functions,which satisfy the governing differential equations and the simply supported boundary conditions at four edges of the plate,are analytically *** reaction forces of the intermediate supports are regarded as the unknown external forces acting on the lower surface of the *** unknown coefficients are then determined by the boundary conditions on the upper and lower surfaces of the *** the numerical results obtained from the proposed method to those obtained from Kirchhoff plate theory,Mindlin plate theory and those obtained from the commercial finite element software ANSYS,the high accuracy of the present method has been demonstrated.

关键词： rectangular plate point support line support elastic foundation displacement stress three-dimensional elasticity solution

Modal parameter identification under non-stationary ambient excitation based on continuous time AR Model

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Science china(Technological Sciences) 2009年第10期52卷 3180-3187页

作者： DU XiuLi1,2 & WANG FengQuan1 1 college of civil engineering, Southeast university, nanjing 210096, china 2 School of Mathematical Sciences, nanjing Normal university, nanjing 210097, china college of civil engineering Southeast University Nanjing China School of Mathematical Sciences Nanjing Normal University Nanjing China

A new time-domain modal identification method of linear time-invariant system driven by the non-stationary Gaussian random excitation is introduced based on the continuous time AR model. The method can identify physical parameters of the system from response data. In order to identify the parameters of the system, the structural dynamic equation is first transformed into the continuous time AR model, and subsequently written into the forms of observation equation and state equation which is just a stochastic differential equation. Secondly, under the assumption that the uniformly modulated function is approximately equal to a constant matrix in a very short time period, the uniformly modulated function is identified piecewise. Then, we present the exact maximum likelihood estimators of parameters by virtue of the Girsanov theorem. Finally, the modal parameters are identified by eigenanalysis. Numerical results show that the method we introduce here not only has high precision and robustness, but also has very high computing efficiency. Therefore, it is suitable for real-time modal identification.

关键词： modal identification uniformly modulated function CAR model exact maximum likelihood estimator

Molecular group dynamics study on slip flow of thin fluid film based on the Hamaker hypotheses

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Science china(Technological Sciences) 2010年第7期53卷 1833-1838页

作者： ZHOU JianFeng, SHAO ChunLei & GU BoQin college of Mechanical and Power engineering, nanjing university of technology, nanjing 210009, china college of Mechanical and Power engineering Nanjing University of Technology Nanjing China

The thin fluid film was assumed to consist of a number of spherical fluid molecular groups and the attractive forces of molecular group pairs were calculated by the derived equation according to the three Hamaker homogeneous material hypotheses. Regarding each molecular group as a dynamics individual, the simulation method for the shearing motion of multilayer fluid molecular groups, which was initiated by two moving walls, was proposed based on the Verlet velocity iterative algorithm. The simulations reveal that the velocities of fluid molecular groups change about their respective mean velocities within a narrow range in steady state. It is also found that the velocity slips occur at the wall boundary and in a certain number of fluid film layers close to the wall. Because the dimension of molecular group and the number of group layers are not restricted, the hypothetical thickness of fluid film model can be enlarged from nanometer to micron by using the proposed simulation method.

关键词： Hamaker hypotheses molecular group velocity slip Lennard-Jones potential

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

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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 university,nanjing 210093,china 2 School of Chemical engineering nanjing university of Science and technology,nanjing 210094,china 3 college of Basic Medical Science,Southeast university,nanjing 210009,china State Key Laboratory of Pharmaceutical Biotechnology College of Life Science Nanjing UniversityNanjing 210093 China School of Chemical engineering Nanjing University of Science and TechnologyNanjing 210094 China college of Basic Medical Science Southeast UniversityNanjing 210009 China

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 25-kDa branched PEI control,and resulted in a 9-fold increase in gene deliveryin B16F10 cells and a 16-fold increase in 293T 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 293T cell line

Statistical study of cement additives with and without chloride on performance modification of Portland cement

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Progress in Natural Science:Materials International 2011年第3期21卷 246-253页

作者： Hong HUANG,Xiao-dong SHEN State Key Laboratory of Materials-Oriented Chemical engineering,college of Material Science and engineering, nanjing university of technology,nanjing 210009,china State Key Laboratory of Materials-Oriented Chemical engineering College of Material Science and Engineering Nanjing University of Technology Nanjing 210009 China

The effectiveness of cement additives with and without chloride on the fluidity and the strength development of Portland cement was compared by using statistical full factorial *** experimental results show that the cement additive containing CaCl2and Ca(NO3)2can enhance early strength of cement ***,Ca(NO3)2is less effective than CaCl2even if it is combined with other organic chemicals such as alkanolamine and *** significant difference is found between CaCl2and Ca(NO3)2influencing the fluidity and 28 d strength of *** fluidity is determined by saccharide and its interaction with *** 28 d strength enhancement is determined by *** fluidity as well as the mechanical performance of treated cement can be significantly improved by combining Ca(NO3)2with TIPA and saccharide.

关键词： Portland cement cement additive accelerator type fluidity strength development full factorial design

Analysis of variance for testing method of cement in determination of strength

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Progress in Natural Science:Materials International 2011年第4期21卷 341-346页

The statistical tools such as descriptive statistics,full factorial design and analysis of source of variation were used to identify the potential factors that impact the validity of testing method for determining the strength of *** results showed that personal error impacted both accuracy and precision of test *** time associated with temperature fluctuation resulted in strength variation but did not impact the precision of test in all curing *** compactions did not impact the precision of test but resulted in the strength variation on 3 d and 28 d *** methods for the initial moist air curing significantly impacted the precision of testing method and resulted in the strength variation of cement on 1 d.

关键词： testing method of cement analysis of variance strength accuracy precision

Integrated intelligent control analysis on semi-active structures by using magnetorheological dampers

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Science china(Technological Sciences) 2008年第12期51卷 2270-2284页

作者： XU ZhaoDong1 & GUO YingQing2 1civil engineering college, Southeast university, nanjing 210096, china 2 Automation college, Southeast university, nanjing 210096, china civil engineering college Southeast University Nanjing China Automation college Southeast University Nanjing China

The control strategy is very important for semiactive control or active control systems. An integrated intelligent control strategy for building structures incorpo rated with magnetorheological (MR) dampers subjected to earthquake excitation is proposed. In this strategy, the time-delay problem is solved by a neural network and the control currents of the MR dampers are determined quickly by a fuzzy controller. Through a numerical example of a three-storey structure with one MR damper installed in the first floor, the seismic responses of the uncontrolled, the intelligently controlled, the passiveon controlled, and the passive-off controlled structures under different earthquake excitations are analyzed. Based on the numerical results, it can be found that the time domain and the frequency domain responses are reduced effectively when the MR damper is added in the structure, and the integrated intelligent control strategy has a better earthquake mitigation effect.

关键词： magnetorheological damper semi-active control intelligent

Mesoporous Si-MCM-48 membrane prepared by pore-filling method

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Science china(Technological Sciences) 2010年第4期53卷 1064-1068页

作者： XU DeKan & FAN YiQun State Key Laboratory of Materials-Oriented Chemical engineering,college of Chemistry and Chemical engineering,nanjing university of technology,nanjing 210009,china State Key Laboratory of Materials-Oriented Chemical engineering College of Chemistry and Chemical Engineering Nanjing University of Technology Nanjing China

Mesoporous MCM-48 membranes were prepared on asymmetric zirconia tubular support with an average pore size of 0.2 μm by hydrothermal *** support should be pretreated with H2O as a pore-filling substance to prevent the sol solution from infiltrating into the support *** SEM showed that the MCM-48 membrane was composed of tightly-connected spherical *** single gas N2 and H2 permeation experiments confirm that crack-free membrane could be prepared by pore-filling method.N2 permeance of MCM-48 membrane,synthesized by secondary growth,can reach 5.66×10-7 mol/Pa·s·m2,and the H2/N2 separation factor was 3.47 under trans-membrane pressure of 0.05 MPa.

关键词： MCM-48 mesoporous membrane pore-filling

Preparation of Exo-tetrahydrodicyclopentadiene Using SiW/Hβ Catalyst

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china Petroleum Processing & Petrochemical technology 2011年第3期13卷 41-46页

作者： Kang Zhuozhuo Wu Wenliang Zhou Zhiwei (college of Chemistry and Chemical engineering,nanjing university of technology,nanjing 210009) college of Chemistry and Chemical engineering Nanjing University of Technology Nanjing 210009 China

Exo-tetrahydrodicyclopentadiene (exo-TCD) is an important high-energy *** acid (SiW) immobilized on H-type β zeolite (Hβ) at room temperature were used to prepare the Hβ zeolite catalysts with different SiW *** performances of the catalysts were investigated during the preparation of exo-TCD via isomerization of endo-tetrahydrodicyclopentadiene (endo-TCD).The properties of catalysts were characterized by XRD,temperature pro-grammed desorption of ammonia (NH 3-TPD),FT-IR,and N 2-adsorption *** was highly dispersed on the surface of Hβ zeolite,and the 10% SiW/Hβ zeolite catalyst had the highest amount of weak acidity among all SiW/Hβ zeolite *** influence of different factors on isomerization reaction was *** a reaction temperature of 240 ℃,a n(cyclohexane) /n(endo-TCD) ratio of 10,a m(catalyst) /m(endo-TCD) ratio of 0.3,an initial pressure of 1.0 MPa,and a reaction time of 1.5 h in the presence of 10% SiW/Hβ catalyst calcined at 400 ℃,the conversion of endo-TCD reached up to 92.0%,with the yield of exo-TCD equating to 51.0%.

关键词：分子筛催化剂四氢制备异构化催化剂催化性能反应温度 TCD X射线衍射