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A Finite-Element Analysis on the Rheorolling Process of Semi-Solid Spring Steel

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Journal of Materials Science & Technology 2003年第z1期19卷 62-64页

作者： Hongbo dong Yonglin kang Department of Material Processing and Controlling University of Science and Technology Beijing Beijing 100083 China Department of Material Processing and Controlling University of Science and Technology Beijing Beijing 100083 China

With a geometrical model of porous material, a 3D finite-element analysis on the rolling process of spring steel60Si2Mn in the semi-solid state is carried out using software MARC. In terms of flat and groove rolling conditions,stress field and strain field are studied. The simulation results show that the rigid-viscoplastic model can accuratelydescribe the semi-solid metal rolling process. Semi-solid slurry has the characteristics of low flow stress and goodfluidity. During groove rolling, distribution of stress and strain on the cross-section of deformation zone is moreuniform than that during flat rolling. The results of simulation are in good agreement with the experiment data, andshow that semi-solid material fits for groove rolling.

关键词： Finite-element analysis, Stress, Strain, Semi-solid metal

基于孟塞尔色彩体系的通山县传统村落色彩风貌控制研究——以宝石村为例

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华中建筑 2025年第1期43卷 119-124页

作者：董黎康美琪武汉科技大学艺术与设计学院

湖北省咸宁市通山县位于鄂、湘、赣三省交界,其聚落布局、结构、工艺、色彩风貌皆体现出多元融合的发展态势,并最终形成极具地域特色的聚落面貌。在当代乡村振兴的国家战略背景下,针对传统村落的色彩风貌控制策略研究,有助于凝练村落特... 详细信息

湖北省咸宁市通山县位于鄂、湘、赣三省交界,其聚落布局、结构、工艺、色彩风貌皆体现出多元融合的发展态势,并最终形成极具地域特色的聚落面貌。在当代乡村振兴的国家战略背景下,针对传统村落的色彩风貌控制策略研究,有助于凝练村落特色、提升环境和谐度,尤其在部分新建民居建筑进入到传统聚落环境中时,由于建筑材料与建造工艺的改变,在最终呈现出的色彩风貌上面临着新旧关系衔接的问题。该文以通山县13个传统村落作为主要调研样本,结合通山县传统村落文献记载和实地照片等定性分析,利用孟塞尔色彩体系的色彩表达方法进行色相、彩度、明度的定量分析,解析通山县传统民居的色彩现状。以宝石村为重点研究对象,选取村落中具有代表性的街巷与典型民居建筑,根据民居搭建年代筛选出可保留的民居色彩,提出推荐色谱,为宝石村提炼出更具地域特色的色彩组成,为其后续修复与发展提供色彩风貌控制的方向与策略。

关键词：孟塞尔色彩体系传统村落民居色彩色彩风貌控制

Mean-field homogenization of elasto-viscoplastic composites based on a new mapping-tangent linearization approach

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Science China(Technological Sciences) 2019年第5期62卷 736-746页

作者： YU Chao kang GuoZheng fang DaiNing Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and EngineeringSouthwest Jiaotong University Institute of Advanced Technology Beijing Institute of Technology

In this work, a new homogenization method of elasto-viscoplastic composites is developed. Using the fully implicit backward Euler's integration algorithm, the nonlinear ordinary differential equations in the constitutive laws of the matrix and inclusion phases are discretized. Three classical incremental linearization approaches, i.e., direct, secant and tangent ones are adopted and an affine relationship between the stress and strain increments is deduced. In order to reduce the interaction between the inclusion and matrix phases, a second-ordered mapping tensor is introduced and a new mapping-tangent linearization approach is proposed. Different linearization approaches are implemented by the incremental self-consistent scheme to predict the overall stress-strain response of particle-reinforced composites. It is shown that the predicted stress-strain curves given by the proposed mapping-tangent linearization approach are softer than that by other three classical ones, and are much closer to that from a fullfield finite element simulation. Moreover, the linearized elasto-viscoplastic constitutive equation based on the proposed mapping-tangent approach has the same mathematical structure as the rate-independent elasto-plastic constitutive law. In this sense,the homogenization problems faced in the elasto-plastic and elasto-viscoplastic heterogeneous materials can be unified.

关键词： micromechanics composites elastic-viscoplasticity self-consistent method mapping-tangent linearization approach

Deciphering fungal metabolon coupling tandem inverse-electrondemand Diels-Alder reaction and semipinacol rearrangement for the biosynthesis of spiro polycyclic alkaloids

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Science China Chemistry 2025年第01期 288-296页

作者： Shuai Liu Wen-Qiang Xu Ying-Tong Di Man-Cheng Tang Ding-kang Chen Ming-Ming Cao Yao-Wen Chang Hong-Yu Tang Chun-Mao Yuan Jun-Bo Yang Zhi-Li Zuo Han Guo Zi-Fei Xu Ying Zeng Yun-dong Wu Xiao-Jiang Hao Key Laboratory of Phytochemistry and Natural Medicines (Chinese Academy of Sciences) Kunming Institute of Botany Chinese Academy of Sciences University of Chinese Academy of Sciences Lab of Computational Chemistry and Drug Design State Key Laboratory of Chemical Oncogenomics Peking University Shenzhen Graduate School Shenzhen Bay Laboratory State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Medical University Molecular Biology Experimental Center Germplasm Bank of Wild Species in Southwest China Kunming Institute of Botany Chinese Academy of Sciences Yunnan Key Laboratory for Wild Plant Resources Kunming Institute of Botany Chinese Academy of Sciences Research Unit of Chemical Biology of Natural Anti-Virus Products Chinese Academy of Medical Sciences

In the intricate process of natural product biosynthesis, a metabolon can enhance metabolic flux by associating sequential enzymes. A fungal metabolon, comprising of flavin-dependent monooxygenase Spe F and P450 monooxygenase Spe G, is identified in the biosynthesis of spiro polycyclic alkaloids(+)-notoamide B and its diastereomer(+)-versicolamide B. Using notoamide E as a substance, Spe F/Spe G metabolon can control the stereoselectivity of its 2,3-epoxidation, followed by hydrogen atom ion at C-17 to generate reactive epoxide tau-m A with dienyl iminium unit. Subsequently,(+)-notoamide B and(+)-versicolamide B are produced via tandem nonenzymatic inverse-electron-demand Diels-Alder reaction and semipinacol rearrangement. This provides the first example of metabolon in the biosynthesis of spiro-prenylated indole alkaloids.

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Exploring the nonlinear piezoresistive effect of 4HSiC and developing MEMS pressure sensors for extreme environments

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Microsystems & Nanoengineering 2023年第2期9卷 59-76页

作者： Chen Wu Xudong fang Qiang kang Ziyan fang Junxia Wu Hongtao He dong Zhang Libo Zha Bian Tian Ryutaro Maedai Zhuangde Jjang State Key Laboratory for Manufacturing Systems Engineering International Joint Laboratory for Micro/Nano Manufacturing and Measurement TechnologiesXian Jiaotong UniversityXian 710049China School of Mechanical Engineering Xian Jiaotong UniversityXi'an 710049China Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai 265503China Xi'an Jiaotong University(Yantai)Research Institute for Intelligent Sensing Technology and System Xi'an Jiaotong UniversityXianChina HeBei Semiconductor Research Institute Shjiazhuang 050051China

Microelectromechanical system(MEMS)pressure sensors based on silicon are widely used and offer the benefits of miniaturization and high ***,they cannot easily withstand high temperatures exceeding 150 ℃ because of intrinsic material ***,we proposed and executed a systematic and full-process study of Sic-based MEMS pressure sensors that operate stably from-50 to 300 ℃.First,to explore the nonlinear piezoresistive effect,the temperature coefficient of resistance(TCR)values of 4H-SiC piezoresistors were obtained from-50 to 500 ℃.A conductivity variation model based on scattering theory was established to reveal the nonlinear variation ***,a piezoresistive pressure sensor based on 4H-SiC was designed and *** sensor shows good output sensitivity(3.38 mVN/MPa),accuracy(0.56%FS)and low temperature coefficient of sensitivity(TCS)(-0.067%FS/℃)in the range of-50 to 300 ℃.In addition,the survivability of the sensor chip in extreme environments was demonstrated by its anti-corrosion capability in H_(2)SO_(4) and NaOH solutions and its radiation tolerance under 5 W ***,the sensor developed in this work has high potential to measure pressure in high-temperature and extreme environments such as are faced in geothermal energy extraction,deep well dilling,aeroengines and gas turbines.

关键词： environments extreme nonlinear

Influence of Blade Outlet Angle on Inner Flow Field of Centrifugal Pump Transporting Salt Aqueous Solution

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Chinese Journal of Mechanical Engineering 2009年第6期22卷 912-917页

作者： YANG Minguan kang Can dong Xiang LIU dong School of Energy and Power Engineering Jiangsu University Zhenjiang 212013 China

During transportation of salt aqueous solutions with centrifugal pump, crystallization phenomenon is frequently encountered. For this kind of two-phase flow, it is difficult to be accurately modeled since there are various medium properties and phase change characteristics. In view of experiment, several problems are hampering the implementation of precise measurement. Influences of blade outlet angle and medium temperature on crystallization rate were studied. Sodium sulfate solution was applied to simulate practical fluid in chemical industry. Particle image velocimetry（PIV） was employed to measure velocity distributions in rotating impeller. Crystallization processes in three impellers with different blade outlet angles were investigated. Relations among crystallization and flow parameters such as temperature and velocity were obtained. With the same blade wrap angle, when blade outlet angle is larger, diffusion of single flow passage gets stronger, relative velocity at blade outlet decreases and large scale vortex tends to appear near the blade working surface. For the impact of volume effect of particle phase on fluid viscosity, both liquid and solid phase velocities decrease with continual forming and growing of crystal particles. Velocity of solid phase is greater than that of liquid phase and its direction leans more closely to blade working surface. Solid particles tend to move towards blade working surface, as is more obvious in the impeller with large blade outlet angle. Therefore, collision between solid particles with stem part of blade working surface is more intensive in impeller with large blade outlet angle. Concerning transportation of salt aqueous solution, accurate PIV measurement is conducted in centrifugal impellers with different blade outlet angles. The results are useful and instructive in relevant engineering design and operation.

关键词： centrifugal pump flow with crystallization blade outlet angle particle image velocimetry(PIV)

A Thermo-Magneto-Mechanically Coupled Constitutive Model of Magnetic Shape Memory Alloys

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Acta Mechanica Solida Sinica 2018年第5期31卷 535-556页

作者： Chao Yu Guozheng kang Daining fang State Key Laboratory of Traction Power Southwest Jiaotong University Chengdu 610031 China Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and Engineering Southwest Jiaotong University Chengdu 610031 China Institute of Advanced Technology Beijing Institute of Technology Beijing 100081 China

A macroscopic phenomenological constitutive model considering the martensite transformation and its reverse is constructed in this work to describe the thermo-magneto- mechanically coupled deformation of polycrystalline magnetic shape memory alloys （MSMAs） by referring to the existing experimental results. The proposed model is established in the frame- work of thermodynamics by introducing internal state variables. The driving force of martensite transformation, the internal heat production and the thermodynamic constraints on constitutive equations are obtained by Clausius dissipative inequality and constructed Gibbs free energy. The spatiotemporal evolution equation of temperature is deduced from the first law of thermodynam- ics. The demagnetization effect occurring in the process of magnetization is also addressed. The proposed model is verified by comparing the predictions with the corresponding experiments. It is concluded that the thermo-magneto-mechanically coupled deformation of MSMAs including the magnetostrietive and magnetocaloric effects at various temperatures can be reasonably described by the proposed model, and the magnetocaloric effect can be significantly improved over a wide range of temperature by introducing an additional applied stress.

关键词： Magnetic shape memory alloys Constitutive model Martensite transformation Thermo-magneto-mechanically coupled deformation Magnetostrictive and magnetocaloric effects

Ecological influence of exotic plants of Sonneratia apetala on understory macrofauna

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Acta Oceanologica Sinica 2012年第5期31卷 115-125页

作者： TANG Yijie fang Zhanqiang CHEN kang ZHANG Zaiwang ZHONG Yanting AN dong YANG Xiongbang LIAO Baowen Department of Biology Guangdong University of Education Guangzhou 510303 China Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education College of Life Sciences South China Normal University Guangzhou 510631 China Administrative Office of Zhuhai Qi'ao-Dangan Island Provincial Nature Reserve Zhuhai 519000 China The Research Institute of Tropical Forestry Chinese Academy of Forestry Guangzhou 510520 China

The study aims to compare the differences of macrofauna communities of wetlands at 3-year-forest- age, 5-year-forest-age Sonneratia apetala artificial mangroves, 5-year-forest-age Kandelia candel ar- tificial mangroves with the same restoration background, and the naked tidal flat in the Qi’ao Island Mangrove Nature Reserve of Zhuhai, Guangdong Province. The results show that there were signif- icant structural differences in macrofauna communities among four kinds of habitats. The increase of biomass and species diversity of macrofauna at 3-year-forest-age S. apetala artificial mangroves was obviously faster than that at 5-year-forest-age K. candel artificial mangroves whose average tree height was close to that of 3-year-forest-age S. apetala artificial mangroves. The BIOENV analysis shows that it was related to the rapid growth of S. apetala, which rapidly changed the light level and shading conditions in the forests. The 5-year-forest-age S. apetala artificial mangroves had lower macrofauna species diversity but higher density and biomass than K. candel artificial mangroves with the same forest age. This was due to the rapid changes of physical and chemical properties of habitat soil by the ecological restoration of S. apetala artificial mangroves as well as the changed food sources possibly caused by the leaf-litter of such non-indigenous mangrove species S. apetala. However, further survey should be conducted on whether there are any negative ecological impacts of large-scale cultivation of S. apetala on macrofauna communities, so as to evaluate correctly S. apetala’s role in the restoration of coastal mangrove ecosystems.

关键词： macrofauna species diversity Sonneratia apetala artificially restored mangroves

Equilibria and Stability Analysis of Cohen-Grossberg BAM Neural Networks on Time Scale

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Journal of Systems Science & Complexity 2022年第4期35卷 1348-1373页

作者： LIU Mingshuo fang Yong dong Huanhe College of Mathematics and Systems Science Shandong University of Science and TechnologyQingdao266590China

This paper considers the Cohen-Grossberg BAM neural networks(CG-BAMNNs) on time scale, which can unify and generalize the continuous and discrete systems. First, the criteria for the existence and uniqueness of the equilibrium of CG-BAMNNs are derived on time scale. Then based on that, the authors give the criteria for the stability and estimation of equilibrium of the CG-BAMNNs on time scale. The method proposed in this paper unifies and generalizes the continuous and discrete CGBAMNNs systems, and is applicable to some other neural network systems on time scale with practical meaning. The effectiveness of the proposed criteria for delayed CG-BAMNNs is demonstrated by numerical simulation.

关键词： Cohen-Grossberg BAM neural networks existence numerical simulation stability uniqueness