检索结果-南通市图书馆

Fold-Hopf bifurcation in a simplified four-neuron BAM (bidirectional associative memory) neural network with two delays

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2010年第3期53卷 633-644页

作者： GE JuHong & XU Jian school of Aerospace Engineering and Applied Mechanics,tongji university,shanghai 200092,china 1. school of Aerospace Engineering and Applied Mechanics Tongji University Shanghai 200092 China

The bidirectional associative memory (BAM) neural network with four neurons and two delays is considered in the present paper.A linear stability analysis for the trivial equilibrium is firstly employed to provide a possible critical point at which a zero and a pair of pure imaginary eigenvalues occur in the corresponding characteristic equation.A fold-Hopf bifurcation is proved to happen at this critical point by the nonlinear *** coupling strength and the delay are considered as bifurcation parameters to investigate the dynamical behaviors derived from the fold-Hopf *** dynamical behaviours are qualitatively classified in the neighbourhood of the fold-Hopf bifurcation point by using the center manifold reduction (CMR) together with the normal *** bifurcating periodic solutions are expressed analytically in an approximate *** validity of the results is shown by their consistency with the numerical simulation.

关键词： codimension-two bifurcation time delay solution classification unfolding centre manifold

The protection effect of β-CD on DNA damage induced by ultrafine TiO_2

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2007年第2期50卷 272-275页

作者： ZHU RongRong,WANG ShiLong,SUN XiaoYu,ZHANG Rui & YAO SiDe school of life Science and Technology,tongji university,shanghai 200092,china 1. school of life Science and Technology Tongji University Shanghai 200092 China

Under the photocatalysis of 365 nm ultraviolet radiation,ultrafine TiO2 caused the oxidative damage of Teasy plasmid DNA. The damage was determined by gel-electrophoresis. Then,a different dose of β-CD was added to the reaction,and the damage was restrained. The rate of damage restraining reached 97% when the mass of β-CD was 4 times as that of TiO2. Through UV scan and IR spectroscopy,it was found that the Ti-O of ultrafine TiO2 was bound with -OH of β-CD cavum and the -OH on the surface of ultrafine TiO2 disappeared,so the formation of ?OH was controlled. The ultrafine TiO2 has been widely used,but it was determined to be carcinogenic by some research. The protection effect of β-CD to DNA in the molecular level takes a new look on the surface modification of nano particles to decrease the toxic effect.

关键词： β-CD ultrafine TiO2 plasmid DNA oxide damage bond reaction damage restrain

Explicit Analytical Solutions for the Shearingand Radial Stresses in Curved Beams

在线全文

学校读者我要写书评

暂无评论

Communications in Nonlinear Science and Numerical Simulation 1999年第2期4卷 151-156页

作者： Aiming YU+ Xiangrong LI+++ (tongji university, shanghai 200092, china)++ (shanghai university, shanghai 200072, china) tongji university Shanghai 200092 China shanghai university Shanghai 200072 China

The shearing stresses in curved beams can be solved explicitly from anintegral equation, which is obtained by differentiation & integral manipulations. Twonovel formulae for shearing & radial stresses are also presented in the paper. The resultsof an example reveal that the shearing & radial stresses arrive at their maximum valuesslightly below the centroid of the section.

关键词： curved beam shearing stress radial stress integral equation

Impact and mechanism of TiO_2 nanoparticles on DNA synthesis in vitro

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 Chemistry 2008年第4期51卷 367-372页

作者： LI ShiQiang, ZHU Hong, ZHU RongRong, SUN XiaoYu, YAO SiDe & WANG ShiLong school of life Science and Technology, tongji university, shanghai 200092, china 1. school of life Science and Technology Tongji University Shanghai 200092 China

The impact of TiO2 nanoparticles on DNA synthesis in vitro in the dark and the molecular mechanism of such impact were studied. The impact of TiO2 nanoparticles on DNA synthesis was investigated by adding TiO2 nanoparticles in different sizes and at various concentrations into the polymerase chain reaction (PCR) system. TiO2 nanoparticles were premixed with the DNA polymerase, the primer or the template, respectively and then the supernatant and the precipitation of each mixture were added into the PCR system separately to observe the impact on DNA synthesis. Sequentially the interaction be- tween TiO2 nanoparticles and the DNA polymerase, the primer or the template was further analyzed by using UV-visible spectroscopy and polyacrylamide gel electrophoresis (PAGE). The results suggest that TiO2 nanoparticles inhibit DNA synthesis in the PCR system in the dark more severely than mi- croscale TiO2 particles at the equivalent concentration and the inhibition effect of TiO2 nanoparticles is concentration dependent. The molecular mechanism of such inhibition is that in the dark, TiO2 nanoparticles interact with the DNA polymerase through physical adsorption while TiO2 nanoparticles do with the primer or the template in a chemical adsorption manner. The disfunction levels of the bio-molecules under the impact of TiO2 nanoparticles are in the following order: the primer > the tem- plate > the DNA polymerase.

关键词： TiO2 nanoparticles PCR DNA synthesis molecular mechanism

STABILITY OF IMPULSIVE LINEAR HYBRID SYSTEMS WITH TIME DELAY

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2010年第4期23卷 738-747页

作者： Yu ZHANG·Jitao SUN Department of Mathematics,tongji university,shanghai 200092,china. JitaoSUN Department of Mathematics Tongji University

This paper investigates the stability of impulsive linear hybrid systems with time *** a number of delay-independent/delay-dependent stability criteria are obtained by using Lyapunovfunctions or Lyapunov *** examples ... 详细信息

关键词： Impulsive linear hybrid system Lyapunov function Lyapunov functional time delay.

The contribution of cis-regulatory elements to head-to-head gene pairs' co-expression pattern

在线全文

学校读者我要写书评

暂无评论

Science china(life sciences) 2009年第1期52卷 74-79页

作者： HAO Pei1,2,YU Yao2,3,ZHANG XiaoYan4,TU Kang2,FAN HaiWei2 & ZHONG Yang1 1 school of life sciences,Fudan university,shanghai 200433,china 2 Bioinformatics Center,Key Lab of Systems Biology,shanghai Institutes for Biological sciences,Chinese Academy of sciences,shanghai 200031,china 3 shanghai Center for Bioinformation Technology,shanghai 200235,china 4.school of life sciences,tongji university,shanghai 200092,china 1. school of life sciences Fudan University Shanghai 200433 China 2. Bioinformatics Center Key Lab of Systems Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai 200031 China 3. shanghai Center for Bioinformation Technology Shanghai 200235 China 4. school of life sciences Tongji University Shanghai 200092 China

Transcription regulation is one of the most critical pipelines in biological process,in which cis-elements play the role as gene expression *** attempt to deduce the principles underlying the co-expression of "head-to-head" gene pairs by analyzing activities or behaviors of the shared cis-elements.A network component analysis was performed to estimate the impact of cis-elements on gene promoters and their activities under different *** discoveries reveal how biological system uses those regulatory elements to control the expression pattern of "head-to-head" gene pairs and the whole transcription regulation system.

关键词： transcription regulation cis-elements "head-to-head" gene pairs

Dependence of binaural loudness summation on interaural level difference and frequency for pure tones

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2010年第5期53卷 834-841页

作者： ZHANG Jie & MAO DongXing Institute of Acoustics,tongji university,shanghai 200092,china 1. Institute of Acoustics Tongji University Shanghai 200092 China

Most of the existing loudness models are based on the diotic listening hypothesis,though human beings always hear in dichotic listening *** this situation,the arithmetic mean of loudness at both ears is usually taken as the approximate value of overall perceived loudness,unaffected by the interaural level difference(ILD).The present work investigated the overall perceived loudness for pure tones in dichotic listening conditions through a subjective *** experimental procedures and systematic errors were investigated to prove the accuracy of the subjective *** results showed that fluctuation was insignificant in the low frequency range,while apparent fluctuation of overall loudness could be observed at a high *** overall loudness deviated from the arithmetic mean value as the ILD became larger.A revised model for overall loudness in dichotic listening conditions was *** proposed model and experiment are consistent.

关键词： dichotic listening subjective experiment interaural level difference overall perceived loudness loudness model

NUMERICAL ANALYSIS OF THE 3-D FLOW FIELD OF PRESSURE ATOMIZERS WITH V-SHAPED CUT AT ORIFICE

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2011年第2期23卷 187-192页

作者： ZHOU Hua school of Aerospace Engineering and Applied Mechanics Tongji University Shanghai 200092 China

Axisymmetric liquid jets have been studied extensively for more than one century, while non-axisymmetric jets are also very common in engineering applications but attract less concern. Based on Eulerian fluid-fluid model in Fluent software, this article analysizes the 3-D flow fields of pressure atomizers with V-shaped cut at orifice, which will result in a non-axisymmetric liquid jet. Flow rate analysis and jet structure analysis are carried out, the results show that the flow rate can be formulated by adding a correction coefficient to the formula of inviscid axisymmetric jets in atomization regime, when the Weber number is low enough to make the flow fall out of atomization regime, and the jet structure together with the flow rate formula will change. Analysis shows that the evolution of the spray and therefore the structure of the liquid jet are affected much by relative velocity and the local volume fraction of liquid phase.

关键词： flow rate fraction distribution gas-liquid interference non-axisymmetric liquid jet pressure atomizer

Flexural and Impact Resistance of FRC/Bamboo Laminate

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2002年第4期18卷 369-371页

作者： Wu YAOState Key Laboratory of Concrete Materials Research, tongji university, shanghai 200092, china Lab. of Concrete Mat. Res. Tongji Univ. Shanghai 200092 China

The flexural and impact resistance of a newly developed FRC/bamboo laminate have been investigated. The laminate considered in this study was combined with reformed bamboo plate and extruded fiber reinforced cementitious (FRC) sheet. Innovated from the raw bamboo, reformed bamboo showed high tensile strength and high strength to weight ratio. It can not only remarkably strengthen the FRC sheet but also reduce the total weight of the laminate. Flexural and impact load, broken energy, deflection and duration were measured. Test results showed that the flexural strength value for the laminate can be improved to greater than 90 MPa, while the impact resistance is increased more than 10 times for the laminate when compared with the FRC sheet only.

关键词： Flexural strength Impact FRC/bamboo composite