检索结果-南通市图书馆

An Improved F-Expansion Method and Its Application to Coupled Drinfel'd-SokolovWilson Equation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2008年第8期50卷 309-314页

作者： ZHAO xue-qin ZHI Hong-Yan Department of Mathematics Qufu Normal University Shandong Rizhao 276826 China Department of Applied Mathematics Dalian University of Technology Dalian 116024 China

With the aid of computerized symbolic computation, an improved F-expansion method is presented to uniformly construct more new exact doubly periodic solutions in terms of rational formal Jscobi elliptic function of nonlinear partial differential equations （NPDFs）. The coupled Drinfel＇d-Sokolov-Wilson equation is chosen to illustrate the method. As a result, we can successfully obtain abundant new doubly periodic solutions without calculating various Jacobi elliptic functions. In the limit cases, the rational solitary wave solutions and trigonometric function solutions are obtained as well.

关键词： Jacobi elliptic function doubly periodic solution rational solitary wave solution

Random Forest-Based Fatigue Reliability-Based Design Optimization for Aeroengine Structures

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2024年第7期140卷 665-684页

作者： xue-qin Li Lu-Kai Song School of Energy and Power Engineering Beihang UniversityBeijing100191China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityKowloonHong Kong999077China Research Institute of Aero-Engine Beihang UniversityBeijing100191China

Fatigue reliability-based design optimization of aeroengine structures involves multiple repeated calculations of reliability degree and large-scale calls of implicit high-nonlinearity limit state function,leading to the traditional direct Monte Claro and surrogate methods prone to unacceptable computing efficiency and *** this case,by fusing the random subspace strategy and weight allocation technology into bagging ensemble theory,a random forest(RF)model is presented to enhance the computing efficiency of reliability degree;moreover,by embedding the RF model into multilevel optimization model,an efficient RF-assisted fatigue reliability-based design optimization framework is *** the low-cycle fatigue reliability-based design optimization of aeroengine turbine disc as a case,the effectiveness of the presented framework is *** reliabilitybased design optimization results exhibit that the proposed framework holds high computing accuracy and computing *** current efforts shed a light on the theory/method development of reliability-based design optimization of complex engineering structures.

关键词： Random forest reliability-based design optimization ensemble learning machine learning

A New General Algebraic Method and Its Application to Shallow Long Wave Approximate Equations

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

Communications in Theoretical Physics 2007年第5X期48卷 781-786页

作者： ZHAO xue-qin ZHI Hong-Yan Department of Mathematics Qufu Normal University Rizhao 276826 China Department of Applied Mathematics Dalian University of Technology Dalian 116024 China

A new general algebraic method is presented to uniformly construct a series of exact solutions for nonlinear evolution equations （NLEEs）. For illustration, we apply the new method to shallow long wave approximate equations and successfully obtain abundant new exact solutions, which include rational solitary wave solutions and rational triangular periodic wave solutions. The method is straightforward and concise, and it can also be applied to other nonlinear evolution equations in mathematical physics.

关键词： new general algebraic method nonlinear evolution equations solitary wave solutions

Reversible hydrogels with tunable mechanical properties for optically controlling cell migration

在线全文

学校读者我要写书评

暂无评论

Nano Research 2018年第10期11卷 5556-5565页

作者： Xin Wu wenmao Huang wen-Hao Wu Bin xue Dongfang Xiang Ying Li Meng qin Fei Sun Wei Wang wen-Bin Zhang Yi Cao Collaborative Innovation Center of Advanced Microstructures National Laboratory of Solid State Microstructure and Department of Physics Nanjing University Nanjing 210093 China Key Laboratory of Polymer Chemistry & Physics of Ministry of Education Center for Soft Matter Science and Engineering College ot Chemistry and Molecular Engineering Peking University Beijing 100871 China Collaborative Innovation Center of Atmospheric Environment and Equipment Technology School of Environmental Science and Engineering Nanjing University olin formation Science & Technology Nanjing 210044 China Department of Chemical and Biomolecular Engineering Division of BioMedical Engineering and Center for Systems Biology & Human Health The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong China

Synthetic hydrogels are widely used as biomimetic in vitro model systems to understand how cells respond to complex microenvironments. The mechanical properties of hydrogels are deterministic for many cellular behaviors, including cell migration, spreading, and differentiation. However, it remains a major challenge to engineer hydrogels that recapture the dynamic mechanical properties of native extracellular matrices. Here, we provide a new hydrogel platform with spatiotemporally tunable mechanical properties to assay and define cellular behaviors under light. The change in the mechanical properties of the hydrogel is effected by a photo-induced switch of the cross-linker fluorescent protein, Dronpa145N, between the tetrameric and monomeric states, which causes minimal changes to the chemical properties of the hydrogel. The mechanical properties can be rapidly and reversibly tuned for multiple cycles using visible light, as confirmed by rheological measurements and atomic force microscopy- based nano-indentation. We further demonstrated real-time and reversible modulation of cell migration behaviors on the hydrogels through photo-induced stiffness switching, with minimal invasion to the cultured cells. Hydrogels with a programmable mechanical history and a spatially defined mechanical hierarchy might serve as an ideal model system to better understand complex cellular functions.

关键词： Dronpa photo-responsive hydrogel mechanical properties cell migration artificial extracellular matrix

Nano high-entropy oxide cathode with enhanced stability for direct borohydride fuel cells

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

Journal of Energy Chemistry 2025年第1期 309-316页

作者： Lei Zhang Lingfeng Kuang Lianke Zhang wen Chu Haiying qin Jing Zhang Junjing He Hualiang Ni Hongzhong Chi New Energy Materials Research Center College of Materials and Environmental Engineering Hangzhou Dianzi University School of Materials Science and Engineering Zhejiang University Key Laboratory of MEMS of Ministry of Education School of Integrated Circuits Southeast University

High-entropy materials have become high-activity electrocatalysis owing to their high-entropy effect and multiple active ***,we synthesize a series of carbon-supported nano high-entropy oxides（HEOs/C）,specifically （PtFeCoNiCu）O/C,using a carbothermal shock （CTS） method for application as a cathode catalyst in direct borohydride fuel cells （DBFCs）.The microstructure of the prepared catalysts was characterized by X-ray photoelectron spectroscopy,X-ray absorption fine structure,and transmission electron *** prepared （PtFeCoNiCu）O/C,with particle sizes ranging from 2 to 4 nm,demonstrates 3.94 transferred electrons towards the oxygen reduction reaction in an alkaline environment,resulting in a minimal H2O2yield of 2.6%.Additionally,it exhibits a Tafel slope of 61 mV dec-1,surpassing that of commercial Pt/C (82 mV dec-1).Furthermore,after 40,000 cycles of cyclic voltammetry（CV） testing,the half-wave potential of （PtFeCoNiCu）O/C shows a positive shift of 3 mV,with no notable decline in the limiting current *** （PtFeCoNiCu）O/C is used as a cathode catalyst in DBFCs,the DBFC achieves a maximum power density of 441 mW cm-2at 60°C and sustains a cell voltage of approximately 0.73 V after 52 h at 30°*** findings confirm that HEO/C is a promising cathode catalyst for DBFCs.

关键词：

New Family of 3-DOF UP-Equivalent Parallel Mechanisms with High Rotational Capability

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 Journal of Mechanical Engineering 2018年第1期31卷 66-77页

作者： Wei Ye qin-Chuan Li Xin-xue Chai Faculty of Mechanical Engineering and Automation Zhejiang Sci-Tech University

Parallel mechanisms(PMs) having the same motion characteristic with a UP kinematic chain(U denotes a universal joint, and P denotes a prismatic joint) are called UP-equivalent PMs. They can be used in many applications, such as machining and milling. However, the existing UP-equivalent PMs suffer from the disadvantages of strict assembly requirements and limited rotational capability. Type synthesis of UP-equivalent PMs with high rotational capability is *** special 2 R1 T motion is briefly discussed and the fact that the parallel module of the Exechon robot is not a UP-equivalent PM is disclosed. Using the Lie group theory, the kinematic bonds of limb chains and their mechanical generators are presented. Structural conditions for constructing such UP-equivalent PMs are proposed,which results in numerous new architectures of UP-equivalent PMs. The high rotational capability of the synthesized mechanisms is illustrated by an example. The advantages of no strict assembly requirements and high rotational capability of the newly developed PMs will facilitate their applications in the manufacturing industry.

关键词： Parallel mechanism Group theory Type synthesis High rotational capability

Topic hierarchy construction from heterogeneous evidence

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2016年第1期10卷 136-146页

作者： Han xue Bing qin Ting LIU Shen LIU School of Computer Science and Technology Harbin Institute of Technology Harbin 150001 China Harbin Engineering University Library Harbin Engineering University Harbin 150001 China

Existing studies on hierarchy construction mainly focus on text corpora and indiscriminately mix numerous top- ics, thus increasing the possibility of knowledge acquisition bottlenecks and misconceptions. To address these problems and provide a comprehensive and in-depth representation of domain specific topics, we propose a novel topic hierar- chy construction method with real-time update. This method combines heterogeneous evidence from multiple sources in- cluding folksonomy and encyclopedia, separately in both ini- tial topic hierarchy construction and topic hierarchy improve- ment. Results of comprehensive experiments indicate that the proposed method significantly outperforms state-of-the- art methods （t-test, p-value 〈 0.000 1）; recall has particularly improved by 20.4% to 38.7%.

关键词： hierarchy construction Chinese topic hierarchy,folksonomy heterogeneous evidence hierarchy update

The axisymmetric long-wave interfacial stability of core-annular flow of power-law fluid with surfactant

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2012年第1期28卷 24-33页

作者： xue-Wei Sun Jie Peng Ke-qin Zhu Department of Engineering Mechanics Tsinghua University100084 BeijingChina

The long wave stability of core-annular flow of power-law fluids with an axial pressure gradient is investigated at low Reynolds number. The interface between the two fluids is populated with an insoluble surfactant. The analytic solution for the growth rate of perturbation is obtained with long wave approximation. We are mainly concerned with the effects of shear-thinning/thickening property and interfacial surfactant on the flow stability. The results show that the influence of shear-thinning/thickening property accounts to the change of the capillary number. For a clean interface, the shear-thinning property enhances the capillary instability when the interface is close to the pipe wall. The converse is true when the interface is close to the pipe centerline. For shear-thickening fluids, the situation is reversed. When the interface is close to the pipe centerline, the capillary instability can be restrained due to the influence of surfactant. A parameter set can be found under which the flow is linearly stable.

关键词： Core-annular flow. Power-law fluid. Interfacial surfactant Long-wave stability

Recovery of gallium from zinc concentrate by pressure oxygen leaching

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2013年第6期32卷 622-626页

作者： xue-Lan Wu wen-qing qin Shun-Ke Wu Xi-Hong Ma Yin-Jian Niu Cong-Ren Yang School of Minerals Processing and Bioengineering Central South University Key Laboratory of Biometallurgy of Ministry of Education Central South University China Association of Nonferrous Metal Industry

Zinc concentrate with high gallium content is one of the main resources of *** gallium presents in the form of isomorphism in tetrahedron coordination with sulfur in *** research was to investigate the amenability of zinc concentrate with high gallium to pressure oxygen *** particle size,sulfuric acid concentration,oxygen partial pressure,additive amount,and time of reaction were *** extraction yields of gallium and zinc are 86%and 98%,*** optimal condition is 100 g of zinc concentrate with particle size smaller than 38 lm,sulfuric acid concentration150 g L-1,leaching temperature 150℃,leaching time120 min,oxygen partial pressure 0.7 MPa,additive amount of 0.2 wt%.

关键词： Gallium Pressure oxygen leaching Zinc concentrate