检索结果-南通市图书馆

Energy-Based Prediction of Low Cycle Fatigue Life of High-Strength Structural Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第10期19卷 47-53页

作者： LUO Yun-rong1,2. HUANG Chong-xiang1, GUO Yi2. WANG Qing-yuan1 (1. college of Architecture and Environment, sichuan university,{2., sichuan, China 2. college of Mechanical engineering, sichuan university of Science and engineering, Zigong 643000, sichuan, China) college of Architecture lind Environment Sichuan University Chengdu Sichuan China college of Mechanical engineering Sichuan University of Science and Engineering Zigong Sichuan China

Energy-based models for predicting the low-cycle fatigue life of high-strength structural steels are presented. The models are based on energy dissipation during average of cycles, cycles to crack propagation and total cycles to failure. Plastic strain energy per cycle was determined and found as an important characteristic for initiation and propagation of fatigue cracks for high-strength structural steels. Fatigue strain-life curves were generated using plastic energy dissipation per cycle (loop area) and compared with the Coffin-Manson relation. Low cycle fatigue life was found similar from both methods. The material showed Masing-type behavior. The cyclic hysterisis energy per cycle was calculated from cyclic stress-strain parameters. The fracture surfaces of the fatigue samples were characterized by scanning electron microscope and the fracture mechanisms were discussed.

关键词： low cycle fatigue high-strength steel energy-based model fatigue life

Studies on the analytical potential energy function of diatomic molecular ion XY^+ using variational method

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2004年第2期47卷 154-164页

作者： LIU Guoyue1,3, SUN Weiguo1,2.& FENG Hao1 1. Institute of Physics, sichuan university, chengdu 61.065, China {2., sichuan university, chengdu 61.065, China 3. Mianyang Teacher抯 college, Mianyang 62.000, China Correspondence should be addressed to Sun Weiguo (e-mail: weiguosun@*** or guoyueliu@ ***) Institute of Physics Sichuan University Chengdu China Mianyang Teacher's college Mianyang China college of chemical {2. Sichuan University Chengdu China

A new analytical potential energy function for diatomic molecular ion XY+ is proposed based on the energy consistent method (ECM). The Coulomb potential included in the new ionic potential contains multipole corrections, converges quickly and is variationally, changeable. The new potential and the ECM are applied to variationally studying the potential energies of eight electronic states of several diatomic molecular ions: the A2. state of CO+, the X2. g + state of Li 2.+ , the X2. g + state of He 2.+ , the 12.u state of Na 2.+ , the A2.u state of N 2.+ , the X1∑+ state of KrH+, the X2.+ state of SiO+ and the A2. state of SO+ ion. The present results agree excellently with the experiment-based Rydberg-Klein-Rees (RKR) potentials, and are superior to the commonly used Huxley-Murrell-Sorbie (HMS) analytical potentials, and are better in some cases than some quantum mechanicalab initio potentials in the ionic asymptotic and dissociation regions.

关键词： potential energy, diatomic ion, electronic state, variational method.

Encapsulation of inorganic particles by dispersion polymerization through ultrasonic irradiation

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2005年第6期48卷 545-552页

作者： ZHANG Kai1,2. FU Qiang1, HUANG Yuhong2.& ZHOU Dehui2.1. college of Polymer Science and engineering,{2., chengdu 61.065, China 2. Institute of Structure Mechanics, China Academy of engineering Physics, Mianyang 62.900, China college of Polymer Science and engineering Sichuan University Chengdu China Institute of Structure Mechanics China Academy of Engineering Physics Mianyang China

The nano-silica/polystyrene composite particles were prepared and characterized according to the following steps. First, the nano-silica particles were pretreated with surfactants under ultrasonic field. Second, the dispersion polymerization of styrene in a water/ethanol (1/6, weight ratio) medium, with poly(N-vinyl pyrrolidone) (PVP) as stabilizer and 2.2.-azobisizobu- tyronitrile (AIBN) as initiator in the presence of nano-silica particles was initiated with N2.purging through ultrasonic irradiation by taking its advantages of multieffect, i.e. dispersion, crushing, activation, and initiation. Finally, the polymerization kinetics characteristics were studied, and the encapsulation of composite particles was investigated with optical microscope, SEM, TEM, FTIR, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).

关键词： composite particle, dispersion polymerization, ultrasonic irradiation.

Silylated and acetylated β-cyclodextrins for gas chromatographic stationary phases

在线全文

学校读者我要写书评

暂无评论

Journal of Central South university of Technology 2001年第4期8卷 239-243页

作者： TANG Ke wen 1,2.,YI Jian ming 2.ZHOU Chun shan 1,ZHONG Shi an 1 (1. college of Chemistry and chemical {2., Central South university, Changsha 410083, China 2. college of Chemistry and chemical {2., Yueyang Normal university college of Chemistry and chemical {2. Central South University Changsha China college of Chemistry and chemical {2. Yueyang Normal University Yueyang China

Two new chiral stationary phases, 2.3 di O acetyl 6 O trimethylsilyl β cyclodextrin (DATBCD) and 2.6 di O trimethylsilyl 3 O acetyl β cyclodextrin(DTABCD), were synthesized, their structures were identified by means of infrared and NMR spectra. Capillary columns were coated with the two stationary phases by dynamic method. The chromatographic properties, and enantiomers separation, such as ketone, esters, alcohols and olefines, were investigated on the silylated and acetylated β cyclodextrin stationary phases. The experimental results show that the silylated and acetylated β cyclodextrins are suitable to be used as capillary gas chromatographic stationary phases, the relative polarity of DATBCD and DTABCD stationary phases is respectively 4143 and 392., the column efficiencies are respectively 3084 and 4198, and DATBCD is of stronger enantioselectivity than DTABCD, capacity factor of the first eluted enantiomer ( k 1) and separation factor(α)of α phenylethanol on DATBCD stationary phase are respectively 8.2. and 1.019.

关键词： capillary gas chromatography silylated and acetylated β-cyclodextrins enantiomeric separation

A Series Piezoelectric Quartz Crystal Response Kinetics for *** Growth in the Presence of Cu(Ⅱ)

在线全文

学校读者我要写书评

暂无评论

Journal of Central South university 2000年第1期12卷 15-19页

作者： CHAI Li yuan 1,2.,WEI Wan zhi 2.YAO Shou zhuo 2.1. Department of Metallurgical Science and engineering, Central South university of Technology, Changsha 410083, China 2. {2. of Chemistry and chemical engineering, Hunan university, Changsha Department of Metallurgical Science and engineering Central South University of Technology Changsha China college of Chemistry and chemical {2. Hunan University Changsha China

The kinetics on the growth of *** in the presence of Cu(Ⅱ) was studied using of series piezoelectric quartz crystal (SPQC). Arsenic ion inhibits the growth of *** , which is consistent with the previous results by other measuring methods. This further demonstrates that the SPQC can monitor the chemical activity of *** growth. Cupric ion accelerates the growth of *** . The mechanism was discussed, i. e., copper promotes the protein enzyme of *** , rusticyanin, to form over the range of cupric ion concentration studied. The reaction order of cupric ion in accelerating the bacterial growth is 0.067. The growth of *** is dependent on temperature, the apparent reaction activation energy decreases from 2..56 kJ/mol to 18.32.kJ/mol because of the addition of 10 mg/L Cu(Ⅱ) to the bacterial growth solution of pH 2.0 at initial inoculum of 10%.

关键词： series piezoelectric quartz crystal T.ferrooxidans growth kinetics sigmoid curve cupric ion

Accurate studies on the full vibrational energy spectra and molecular dissociation energies for some electronic states of N_(2.molecule

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2005年第4期48卷 385-398页

作者： REN Weiyi1,2. SUN Weiguo1, HOU Shilin3 & FENG Hao4 1. Institute of Physics, college of chemical {2., sichuan university, chengdu 61.065, China 2. Institute of Theoretical Physics, Xihua Normal university, Nanchong 637002. China 3. Department of Physics, China Oceanography university, Qingdao 2.6003, China 4. college of Physics, sichuan university, chengdu 61.065, China Institute of Physics College of Chemical Engineering Sichuan University Chengdu China Institute of Theoretical Physics Xihua Normal University Nanchong China Department of Physics China Oceanography University Qingdao China college of Physics Sichuan University Chengdu China

It is usually very difficult to directly obtain molecular dissociation energy De and all accurate high-lying vibrational energies for most diatomic electronic states using modern experimental techniques or quantum theories, and it is also very difficult to give accurate analytical expression for diatomic molecular dissociation energy. This study proposes a new analytical formula for obtaining accurate molecular dissociation energy based on the LeRoy and Bernstein’s energy expression in dissociation limit. A set of full vibrational energy spectra for some electronic states of N2.molecule are studied using the algebraic method (AM) suggested recently, and the corresponding accurate molecular dissociation energies are evaluated using the proposed new formula and high-lying AM vibrational energies. The results show that the AM spectra and the new theoretical dissociation energies agree excellently with experimental data, and thereby providing a new physical approach to generating accurate dissociation energies for electronic states of diatomic molecules.

关键词： vibrational energy, dissociation energy, nitrogen molecule, algebraic method.

Theoretical study on the hydrolysis mechanism of N,N-dimethyl-N′-(2.,3′-dideoxy-3′-thiacytidine)formamidine

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2008年第10期51卷 911-917页

作者： ZHANG Chang1 & XUE Ying2. 1 college of Chemistry and Environment Protection engineering, Southwest {2. for Nationalities, chengdu 610041, China 2.college of Chemistry, sichuan university, chengdu 610064, China college of Chemistry and Environment Protection engineering Southwest University for Nationalities Chengdu China college of Chemistry Sichuan University Chengdu China

The hydrolysis mechanisms of N,N-dimethyl-N′-(2.,3′-dideoxy-3′-thiacytidine)formamidine (FA-3TC) in the gas phase and in aqueous solution were studied by use of the density functional theory B3LYP/6-31+G(d, p) method. Two possible reaction pathways in the title reaction were considered. In one pathway water attacks the C=N double bond first (path A) while in the other water attacks the C—N single bond first (path B). The calculated results indicate that the first step in both pathways is the rate-limiting process and path A is more favorable than path B in the gas phase. The effect of solvent water on the title reaction was assessed at the B3LYP/6-31+G(d, p) level of theory based on the po-larizable continuum model (CPCM). In water the first mechanism (path A) is also favored.

关键词： N N-dimethyl-N′-(2. 3′-dideoxy-3′-thiacytidine)formamidine hydrolysis solvent effect B3LYP polarizable continuum model

Optimization of thermomechanical processes in Cu-Cr-Zr lead frame alloy using neural networks and genetic algorithms

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2005年第5期48卷 510-520页

作者： SU Juanhua1,2. LIU Ping2. DONG Qiming2.& LI Hejun1 1. college of Materials Science and engineering, Northwestern Polytechnical {2., Xi’an 710072. China 2. college of Materials Science and engineering, Henan {2. of Science and Technology, Luoyang 471003, China college of Materials Science and engineering Northwestern Polytechnical University Xi’an China college of Materials Science and engineering Henan University of Science and Technology Luoyang China

The thermomechanical treatment process is effective in enhancing the properties of the lead frame copper alloy. In this study, an optimal pattern of the thermomechanical processes for Cu-Cr-Zr was investegated using an intelligent control technique consisting of neural networks and genetic algorithms. The input parameters of the artificial neural network (ANN) are the reduction ratio of cold rolling, aging temperature and aging time. The outputs of the ANN model are the two most important properties of hardness and conductivity. Based on the successfully trained ANN model, genetic algorithms (GA) are used to optimize the input parameters of the model and select perfect combinations of thermomechanical processing parameters and properties. The good generalization performance and optimized results of the integrated model are achieved.

关键词： Cu-Cr-Zr alloy, thermomechanical processing optimization, artificial neural network, genetic algorithms.

One approach to calculating the solvent reorganization energy of intramolecular electron transfer

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2003年第1期48卷 35-38页

作者： FU Kexiang1,2. LI Xiangyuan1, ZHU Quan1 & LU Shenzhuang1 1. college of chemical {2., sichuan university, chengdu 61.065, China 2. college of Physics, sichuan university, chengdu 610064, China Correspondence should be addressed to Li Xiangyuan (e-mail: xyli@***) college of chemical {2. Sichuan University Chengdu 610065 China college of Physics Sichuan University Chengdu 610064 China

On the basis of the electromagnetic field theory and the spherical cavity approximation, the expressions ofGibbs free energies under equilibrium and non-equilibrium solvation conditions are obtained by solving the electrostatic potential equations with boundary conditions. The surface charges produced by the orientational polarization of equi-librium solvation are taken fixed in the case of non-equilibrium situation, for the slow-response of the orientational polarization to electron transfer of the solvent molecules. Anew expression of solvent reorganization energy has beenobtained and this method is applied to the electron transfer systems, NO+/NO, NO2./NO2. and NO2./NO. The solvent reorganization energies have been evaluated.

关键词：分子内电子传递溶剂重排能定向极化自由能电子极化计算方法