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Parametric characteristic of the random vibration response of nonlinear systems

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Acta Mechanica Sinica 2013年第2期29卷 267-283页

作者： Xing-Jian dong Zhi-Ke Peng wen-Ming Zhang Guang Meng fu-Lei Chu State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Department of Precision Instruments Tsinghua University

Volterra series is a powerful mathematical tool for nonlinear system analysis,and there is a wide range of nonlinear engineering systems and structures that can be represented by a Volterra series *** the present study,the random vibration of nonlinear systems is investigated using Volterra *** expressions were derived for the calculation of the output power spectral density（PSD） and input-output cross-PSD for nonlinear systems subjected to Gaussian *** on these expressions,it was revealed that both the output PSD and the input-output crossPSD can be expressed as polynomial functions of the nonlinear characteristic parameters or the input *** studies were carried out to verify the theoretical analysis result and to demonstrate the effectiveness of the derived *** results reached in this study are of significance to the analysis and design of the nonlinear engineering systems and structures which can be represented by a Volterra series model.

关键词： Volterra series·Nonlinear system·Random vibration·Power spectrum density·Generalized frequency response functions

Effects of Cold Rolling Reduction on Retained Austenite Fraction and Mechanical Properties of High-Si TRIP Steel

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Journal of Iron and Steel Research International 2013年第5期20卷 50-56页

作者： fu Yong-tao LIU Jing SHI Jie CAO wen-quan dong Han Wuhan University of Science and Technology Research and Development Center WISCO National Engineering Research Center of Advanced Steel Technology Central Iron and Steel Research Institute

Transformation-induced plasticity-aided steel was rolled at room temperature to different thickness reductions （0, 4%, 10%, 20%, 40%, and 60%）. The mechanical properties, microstructure and austenite fractions of the rolled samples were measured by tensile test, electron back scattered diffraction （EBSD） and X-ray diffraction （XRD） for each rolling. The deformation behavior was studied based on the analysis of the mechanical properties and microstructure of steel after tensile deformation, aiming at understanding the effects of cold rolling reduction on the decay behavior of the austenite and the change of mechanical properties of the TRIP steels. It was found that increasing rolling reduction increases the yield stress gradually but decreases the total elongation significantly. It is very interesting that after 10% rolling reduction the yield stress is about 1 000 MPa but still with 20% total elongation, which gives an excellent combination of yield strength and ductility. Based on the XRD results, it was revealed that in both rolling and tension the austenite volume fraction monotonically decayed with the increase of rolling strain, but the decaying rate is faster in tension than in rolling, which may be ascribed to the higher temperature in rolled specimens than in the tensioned ones during deformation. Experimental results and theoretical reasoning indicate that the decreasing trend of austenite volume fraction with strain can be formulated by a unique equation.

关键词： TRIP steel cold rolling mechanical stability austenite fraction

Resolution enhancement in hydrophobic interaction chromatography via electrostatic interactions

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Chinese Chemical Letters 2013年第5期24卷 419-421页

作者： dong Gao fu-Chun Tan wen-Peng Wang Li-Li Wang Key Laboratory of Synthetic and Natural functional Molecular Chemistry of Ministry of Education Shaanxi Key Laboratory of Modern Separation ScienceInstitute of Modern Separation ScienceNorthwest University

In this work,a new type of hydrophobic stationary phase that provide electrostatic interactions with analytes was developed by bondingβ-phenylethylamine as a functional ligand to *** stationary phase can separate proteins with similar hydrophobicity that traditional hydrophobic resins *** egg white was separated to examine the *** results show that the introduced electrostatic interactions are an important factor for the resolution enhancement and the new resin could have important applications in separation and purification of biological macromolecules.

关键词： Hydrophobic interaction chromatography Electrostatic interaction Resolution Hen egg white

A Gradient Descent Method for Estimating the Markov Chain Choice Model

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Journal of the Operations Research Society of China 2023年第2期11卷 371-381页

作者： Lei fu dong-dong Ge School of Information Management and Engineering Shanghai University of Finance and EconomicsShanghai 200433China

In this paper,we propose a gradient descent method to estimate the parameters in a Markov chain choice ***,we derive closed-form formula for the gradient of the log-likelihood function and show the convergence of the *** experiments verify the efficiency of our approach by comparing with the expectation-maximization *** show that the similar result can be extended to a more general case that one does not have observation of the no-purchase data.

关键词： Markov chain choice model Parameter estimation Gradient descent method

Ring Clinal Variation in Morphology of the Green Odorous Frog(Odorrana margaretae)

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Asian Herpetological Research 2020年第2期11卷 108-114页

作者： Guannan wen Jinzhong fu Chengdu Institute of Biology Chinese Academy of SciencesChengdu 610041SichuanChina University of Chinese Academy of Sciences Beijing 100049China Department of Integrative Biology University of GuelphOntario NIG 2W1Canada

The green odorous frog(Odorrana margaretae)has an interesting ring-shaped divergence pattern around the Sichuan Basin and documenting its morphological variations is essential in understanding its evolutionary *** curvilinear models,we detected significant geographical clinal variations in morphological traits,particularly sizes,of female *** had significantly smaller sizes than females,and also had smaller variation ranges than *** major trend of morphological variations was clinal:populations from the west tended to have a larger size with wider head and longer posterior limbs than populations from the *** history,with an early extended isolation and two subsequent secondary contacts,may explain most of the geographical clinal variations of *** factors may also contribute in explaining the variance of morphology.

关键词： geographical clinal intraspecific variation morphology Odorrana margaretae

Recent Advances of Bismuth Oxychloride Photocatalytic Material: Property, Preparation, and Performance Enhancement

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Journal of Electronic Science and Technology 2020年第2期18卷 119-137页

作者： wen-wen Liu Ren-fu Peng College of Physical Science and Engineering Yichun UniversityYichun 336000

Due to its unique layered structure, bismuth oxychloride(BiOCl) has potential applications as a photocatalytic material in clean energy utilization and environmental purification. In recent years, researchers have carried out a lot of studies and made important progress for the preparation and performance enhancement of *** this review, the charge separation property of BiOCl was analyzed based on the crystal structure and electronic structure. Subsequently, the common preparation method of BiOCl was expounded, and the growth mechanism of BiOCl was introduced. furthermore, the strategies for modulating the photocatalytic performance of BiOCl via doping, vacancy creation, internal electric field tuning, co-catalysts modification, composites construction, and using sensitizers were summarized. Finally, in view of the current research status of the BiOCl photocatalytic material, some problems still need to be addressed including exploring the method of controlled synthesis of BiOCl exposed other high energy surfaces, developing advanced characterization methods to clarify the detailed transfer path of the photogenerated charge, and expanding the photocatalytic application range of BiOCl.

关键词： structure. summarized vacancy

Shape-dependent hydrogen generation performance of Pt Pd bimetallic co-catalyst coupled with C_(3)N_(4)photocatalyst

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Rare Metals 2021年第12期40卷 3554-3560页

作者： wen-wen Liu Jun Pan Ren-fu Peng College of Physical Science and Engineering Yichun UniversityYichun 336000China State Key Laboratory for Powder Metallurgy Central South UniversityChangsha 410083China

The shape-dependent performance of metal cocatalysts in photocatalysis has been one of the research focal points in recent *** this study,Pt Pd/C_(3)N_(4)hybrid structures were constructed to reveal the effect of the shape of the Pt Pd bimetallic co-catalyst on the performance of photocatalytic hydrogen *** Pd nanocubes(NCs)and nanotetrahedrons(NTs)were sequentially deposited in situ on the surface of C_(3)N_(4)nanosheets,establishing a strong contact interface to ensure the smooth transfer of photoinduced ***-visible(UV-Vis)diffuse reflectance spectroscopy and photoelectrochemical experiments revealed that the Pt Pd NCs/C_(3)N_(4)photocatalyst had comparable light absorption ability and equivalent carrier separation and transfer efficiency in comparison with the Pt Pd NTs/C_(3)N_(4)photocatalyst,which excluded the influence of these factors on shape-dependent *** photocatalytic hydrogen generation results indicate that the hydrogen generation rate of the Pt Pd NCs/C_(3)N_(4)photocatalyst is 1.33 times higher than that of the Pt Pd NTs/C_(3)N_(4)photocatalyst,demonstrating that the cubic Pt Pd bimetallic co-catalyst is more conducive to hydrogen generation compared to the tetrahedral Pt Pd bimetallic co-catalyst.

关键词： PtPd bimetallic co-catalyst C_(3)N_(4) Shape Hydrogen generation Photocatalyst

A Line Search SQP-type Method with Bi-object Strategy for Nonlinear Semidefinite Programming

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Acta Mathematicae Applicatae Sinica 2022年第2期38卷 388-409页

作者： wen-hao fu Zhong-wen CHEN School of Mathematical Sciences Suzhou University of Science and TechnologySuzhou 215009China School of Mathematical Sciences Soochow UniversitySuzhou 215006China

We propose a line search exact penalty method with bi-object strategy for nonlinear semidefinite *** each iteration,we solve a linear semidefinite programming to test whether the linearized constraints are consistent or *** search direction is generated by a piecewise quadratic-linear model of the exact penalty *** penalty parameter is only related to the information of the current iterate *** line search strategy is a penalty-free *** and local convergence are analyzed under suitable *** finally report some numerical experiments to illustrate the behavior of the algorithm on various degeneracy situations.

关键词： nonlinear semidefinite programming bi-object strategy global convergence rate of convergence

Lattice QCD Study of the σ Meson

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Chinese Physics Letters 2011年第8期28卷 43-46页

作者： fu Zi-wen Key Laboratory of Radiation Physics and Technology(Ministry of Education) Sichuan UniversityInstitute of Nuclear Science and TechnologySichuan UniversityChengdu 610064

We study theσmeson in 2+1 flavor full quantum chromodynamics(QCD)with sufficiently light u and d *** point−to-point correlator is measured for theσchannel in the“Asqtad”improved staggered fermion *** attention is paid to its disconnected diagram and bubble *** chiral extrapolation,we obtain theσmass with 706±53 MeV,which is close to the observedσmeson within error,and is heavier than theππ*** simulations are carried out with MILC 2+1 flavor gauge configurations at lattice spacing of a≈0.15 fm.

关键词： meson QCD gauge