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考虑模态振型影响的斜拉桥非线性内共振能量转换研究

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中国公路学报 2024年第9期37卷 157-169页

作者：陈柯帆李源卢涛贺拴海宋一凡杨鹏任祥伟长安大学公路学院陕西西安710064 阿尔托大学土木工程学院南芬兰埃斯波02150 长安大学旧桥检测与加固技术交通行业重点实验室陕西西安710064 保利长大工程有限公司广东广州510000

为研究斜拉桥面内局部模态与整体模态耦合激发非线性的振动复杂机理,针对索-梁耦合结构1∶1内共振进行了数值仿真和模型试验,分析了模态振型影响下的内共振能量转换进程及特点。首先,考虑了由拉索初始垂度引起的几何非线性,建立了由斜... 详细信息

为研究斜拉桥面内局部模态与整体模态耦合激发非线性的振动复杂机理,针对索-梁耦合结构1∶1内共振进行了数值仿真和模型试验,分析了模态振型影响下的内共振能量转换进程及特点。首先,考虑了由拉索初始垂度引起的几何非线性,建立了由斜拉索与参数质量梁段构成的索-梁耦合动力学模型。然后,根据索-梁端动态耦合条件,基于达朗贝尔原理推导了索、梁动力控制方程,采用有限差分方法代数转换了梁段控制方程的二阶偏微分项以便进行数值求解,通过模态拖拽法和分离变量法得到了结构无穷维的常微分方程组和模态函数。最后,基于4阶Runge-Kutta方法建立了数值仿真程序,结合整体模态振型的影响,分析了1∶1内共振下的能量转换问题,并通过模型试验进行了验证。结果表明:内共振发生时,索-梁锚固点是系统能量进行周期性动态转换的通道,其对应的整体模态振型幅值对能量转换影响较大;锚固于某阶整体模态振型驻点处的拉索即使满足频率比例关系,亦无法被激励产生内共振;拉索的1阶与2阶内共振响应彼此独立,无明显干扰效应;局部与整体模态频率满足等比关系是引发内共振的前提,局部及整体模态间的周期性能量传递是产生内共振的根本原因,而索-梁锚点对应的模态有效参与系数是内共振下能量转换的重要量化指标。

关键词：桥梁工程 1∶1内共振模型试验能量传递面内模态振型有限差分法

Regulating the Electron-Deficient Component in A-DA1D-A Typed Small-Molecule Acceptors for High-Performance Organic Solar Cells

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Chinese Journal of Chemistry 2024年第6期42卷 623-630页

作者： Weifei Wei Ruijie Ma Zhanxiang chen Tongle Xu Gang Li Zhenghui Luo Shenzhen Key Laboratory of New Information Display and Storage Materials College of Materials Science and EngineeringShenzhen UniversityShenzhenGuangdong518060 China Department of Electronic and Information Engineering Research Institute for Smart Energy (RISE)The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong999077 China

Fine-tuning of the electron-deficient unit in A-DA1D-A typed small-molecule acceptors (SMAs) plays a crucial role in developing efficient SMAs for organic solar cells (OSCs).Here,we developed a SMA based on benzo[4,5]thieno[2,3-b]quinoxaline,designated as QW1,as well as three SMAs based on 1-methylindoline-2,3-dione,identified as QW2,QW3,and *** with QW2,QW1 displays slightly blue-shifted absorption spectra and a lower LUMO energy level due to the stronger electron-withdrawing capability of BTQx in contrast to *** the other hand,the introduction of a bromine atom in QW3 and QW4 causes a blue shift in absorption and a reduction in the LUMO energy level compared to *** functional theory analysis reveals that QW1 exhibits the best molecular planarity,which endows QW1 with larger electron mobility and tighter molecular ***,PM6:QW1 device affords a better efficiency of 15.63% than those of the devices based on QW2 (14.25%),QW3 (13.21%) and QW4 (15.03%).Moreover,the QW4-based device yields the highest open-circuit voltage of 0.933 V,and the PM6:L8-BO:QW4 ternary device realizes a PCE of 19.03%.Overall,our work demonstrates that regulation of electron-deficient central units is an effective strategy to improve the photovoltaic performance of the resulting A-DA1D-A SMAs.

关键词： Organic solar cells Small-molecule acceptor Electron-deficient unit Energy conversion efficiency Renewable resources π-πstacking Green chemistry

Corrosion Resistance of Graphene-Reinforced Waterborne Epoxy Coatings

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Journal of Materials Science & Technology 2016年第5期32卷 425-431页

作者： shuan Liu Lin Gu Haichao Zhao Jianmin chen Haibin Yu Key Laboratory of Marine Materials and Related Technologies Zhejiang Key Laboratory of Marine Materials and Protective Technologies Ningbo Institute of Materials Technologies and Engineering Chinese Academy of Sciences

Graphene （G） was dispersed uniformly in water and used as an inhibitor in waterborne epoxy coatings. The effect of dispersed G on anticorrosion performance of epoxy coatings was evaluated. The composite coatings displayed outstanding barrier properties against H20 molecule compared to the neat epoxy coating. Open circuit potential （OCP）, Tafel and electrochemical impedance spectroscopy （EIS） analysis confirmed that the corrosion rate exhibited by composite coatings with 0.5 wt% G was an order of magnitude lower than that of neat epoxy coating. Salt spray test results revealed superior corrosion resistance offered by the composite coating.

关键词： Waterborne epoxy coating Graphene Corrosion resistance Electrochemical impedance spectroscopy(EIS)

Damage evolution model of strain hardening cementitious composites under the uniaxial stress state

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International Journal of Minerals,Metallurgy and Materials 2013年第2期20卷 196-204页

作者： Rui He shuan-fa chen Pei-liang Cong Shao-hua Ji School of Highway Chang'an University Via Department of Civil and Environmental Engineering Virginia Polytechnic Institute and State UniversityBlacksburg VA 24061USA Engineering Research Center of the Ministry of Education for Transportation Materials Chang'an University

The deformation and damage behaviors of strain hardening cementitious composites （SHCC） under the uniaxial stress state were investigated in this paper. Two ductile failure-based constitutive models were introduced to describe the uniaxial tension and compression properties of SHCC only using a few parameters. The computation method of model parameters was developed to ease the simulation procedures. Damage evolution of the SHCC was simulated by the formulation of continuum damage mechanics subsequently. The results show that the proposed models fit the stress-strain curves reasonably well, and the damage variables show different growth rules under uniaxial tension and compression. It is concluded that the proposed method can not only simply simulate the constitutive behavior of SHCC with the reasonable accuracy but also capture the characteristic of material degradation.

关键词： cementitious composites strain hardening constitutive models ductile fracture continuum damage mechanics

Twisting theory for weak Hopf algebras

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Applied Mathematics(A Journal of Chinese Universities) 2008年第1期23卷 91-100页

作者： chen Ju-zhen ZHANG Yan WANG shuan-hong Dept. of Math. Southeast Univ. Nanjing 210096 China.

The main aim of this paper is to study the twisting theory of weak Hopf algebras and give an equivalence between the （braided） monoidal categories of weak Hopf bimodules over the original and the twisted weak Hopf a... 详细信息

关键词： weak Hopf algebra weak Hopf bimodule twisting theory.

Electro-catalytic degradation of sulfisoxazole by using graphene anode

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Journal of Environmental Sciences 2016年第5期28卷 54-60页

作者： Yanyan Wang shuan Liu Ruiping Li Yingping Huang Chuncheng chen Collaborative Innovation Center for Geo-Hazards and Eco-Environment in Three Gorges Area Yichang 443002 China Key Laboratory of Marine New Materials and Application Technology Ningbo Institute of Materials Technology and EngineeringChinese Academy of Sciences Ningbo 315201 China

Graphite and graphene electrodes were prepared by using pure graphite as precursor. The electrode materials were characterized by a scanning electron microscope（SEM）, X-ray diffraction（XRD） and cyclic voltammetry（CV） measurements. The electro-catalytic activity for degradation of sulfisoxazole（SIZ） was investigated by using prepared graphene or graphite anode. The results showed that the degradation of SIZ was much more rapid on the graphene than that on the graphite electrode. Moreover, the graphene electrode exhibited good stability and recyclability. The analysis on the intermediate products and the measurement of active species during the SIZ degradation demonstrated that indirect oxidation is the dominant mechanism, involving the electro-catalytic generation of OH and O_2^- as the main active oxygen species. This study implies that graphene is a promising potential electrode material for long-term application to electro-catalytic degradation of organic pollutants.

关键词： Graphite Graphene Electro-catalytic Degrade Sulfisoxazole

Experimental and numerical studies of micro PEM fuel cell

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Acta Mechanica Sinica 2011年第5期27卷 627-635页

作者： Rong-Gui Peng chen-chung chung Chiun-Hsun chen Department of Mechanical Engineering National Chiao Tung UniversityHsinchu Taiwan China

A single micro proton exchange membrane fuel cell （PEMFC） has been produced using Micro-electromechanical systems （MEMS） technology with the active area of 2.5 cm 2 and channel depth of about 500 μ m.A theoretical analysis is performed in this study for a novel MEMS-based design of a micro *** model consists of the conservation equations of mass,momentum,species and electric current in a fully integrated finite-volume solver using the CFD-ACE＋ commercial *** polarization curves of simulation are well correlated with experimental ***-dimensional simulations are carried out to treat prediction and analysis of micro PEMFC temperature,current density and water distributions in two different fuel flow rates （15 cm 3 /min and 40 cm 3 /min）.Simulation results show that temperature distribution within the micro PEMFC is affected by water distribution in the membrane and indicate that low and uniform temperature distribution in the membrane at low fuel flow rates leads to increased membrane water distribution and obtains superior micro PEMFC current density distribution under 0.4 V operating *** predictions are well within those known for experimental mechanism phenomena.

关键词： Micro PEMFC · MEMS · Simulation · Fuel flow rate

High glucose reduces Nrf2-dependent cRAGE release and enhances inflammasome-dependent IL-1βproduction in monocytes:the modulatory effects of EGCG

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Food Science and Human Wellness 2024年第3期13卷 1531-1542页

作者： Chi-Hao Wu Yin-Hsuan Chang Chin-Lin Hsu Sheng-Yi chen Gow-Chin Yen Graduate Programs of Nutrition Science School of Life ScienceTaiwan Normal UniversityTaipei 106209TaiwanChina Department of Food Science and Biotechnology Chung Hsing UniversityTaichung 40227TaiwanChina School of Nutrition Chung Shan Medical UniversityTaichung 40201TaiwanChina

Soluble receptor for advanced glycation end products(sRAGE)acts as a decoy sequestering of RAGE ligands,thus preventing the activation of the ligand-RAGE axis linking human ***,the molecular mechanisms underlying sRAGE remain *** this study,THP-1 monocytes were cultured in normal glucose(NG,5.5 mmol/L)and high glucose(HG,15 mmol/L)to investigate the effects of diabetesrelevant glucose concentrations on sRAGE and interleukin-1β(IL-1β)*** modulatory effects of epigallocatechin gallate(EGCG)in response to HG challenge were also *** enhanced intracellular reactive oxygen species(ROS)generation and RAGE *** secretion of sRAGE,including esRAGE and cRAGE,was reduced under HG conditions,together with the downregulation of a disintegrin and metallopeptidase 10(ADAM10)and nuclear factor erythroid 2-related factor 2(Nrf2)nuclear ***,the HG effects were counteracted by siRAGE and exacerbated by *** immunoprecipitation results showed that Nrf2 binding to the ADAM10 promoter and HG interfered with this *** data reinforce the notion that RAGE and Nrf2 might be sRAGE-regulating *** HG conditions,the treatment of EGCG reduced ROS generation and RAGE ***-stimulated cRAGE release was likely caused by the upregulation of the Nrf2-ADAM10 *** inhibited HG-mediated NLRP3 inflammasome activation at least partly by stimulating sRAGE,thereby reducing IL-1βrelease.

关键词： Epigallocatechin gallate(EGCG) Inflammasome Nuclear factor erythroid 2-related factor 2(Nrf2) Receptor for advanced glycation end products(RAGE) Soluble RAGE(sRAGE)

Representation of global precipitation anomalies using four major climate patterns

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Science China(Technological Sciences) 2015年第5期58卷 927-934页

作者： chen Ji chung ChiHang Department of Civil Engineering The University of Hong Kong

This study aims at finding the dominant climate patterns that influence the precipitation anomalies for different regions over the world. To this end, a multiple linear regression model is employed to represent the impact of four major climate patterns(El Ni?o-Southern Oscillation(ENSO), Indian Ocean Dipole(IOD), Arctic Oscillation(AO) and Antarctic Oscillation(AAO)) on the global precipitation anomalies. The normalized climate pattern indexes and normalized precipitation anomalies are used in the regression model. For the Northern Hemisphere, the three predictors used are the normalized NINO3.4 index(representing ENSO), normalized DMI(representing IOD) and normalized AO index; for the Southern Hemisphere, also three indexes are used as three predictors, and the normalized AO index is replaced by the normalized AAO index. The influences brought by each climate pattern can be represented by the magnitude of the corresponding regression coefficients, and the dominant climate patterns are those with the largest magnitude. The study results show that the precipitation anomalies in the northern part of South America and the northwestern part of Southeast Asia are mainly influenced by ENSO. The precipitation anomalies in East Africa and the southwestern part of Southeast Asia are mainly influenced by IOD. The precipitation anomalies in Europe and west coast of North America are mainly influenced by AO; the precipitation anomalies in the eastern part and southern part of South America, southern part of Africa, and the northeastern Australia are mainly influenced by AAO. These findings are consistent with the general understanding on the teleconnection features of the four climate patterns. Further, the regression model can be used for predicting precipitation anomalies through use of these major climate patterns.

关键词： normalized ENSO Southeast representing Australia southwestern Arctic trained instead brought