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Frontiers of Structural and Civil Engineering 2024年第7期18卷 1117-1133页

作者： pengfei dou Hao LIU Chengshun XU Jinting WANG Yilong SUN Xiuli DU Department of Hydraulic Engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Urban Security and Disaster Engineering of the Ministry of Education Beijing University of TechnologyBeijing 100124China

This study investigates the seismic response and failure mode of a pile-structure system in a liquefiable site by employing a numerical simulation model combined with the shaking-table results of a soil-pile-structure dynamic *** pile and soil responses obtained from the numerical simulations agreed well with the experimental *** slopes of the dynamic shear-stress-shear-strain hysteretic curves at different positions also exhibited a decreasing trend,indicating that the shear strength of the soil in all parts of the foundation *** peak acceleration of the soil and pile was not clearly amplified in the saturated sand layer but appeared to be amplified in the top *** maximum bending moments appeared in the middle and lower parts of the pile shaft;however,the shear forces at the corresponding positions were not *** can be observed from the deformation mode of the pile-group foundation that a typical bending failure is caused by an excessive bending moment in the middle of the pile shaft if the link between the pile top and cap is articulated,and sufficient attention should be paid to the bending failure in the middle of the pile shaft.

关键词： numerical simulation soil liquefaction pile foundation shaking-table experiment seismic responses failure model

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基于热点温度仿真的光伏电站变压器容量优化

电工技术 2024年第9期 139-141页

作者：窦鹏飞华电海南物资有限公司海南海口570100

光伏电站项目的设计规划中,大多数的主变压器容量都较大。通过分析光伏系统每小时的发电数据与环境的温度状况,结合计算可得出主变每小时的热点温度及对应的热老化参数,进而准确模拟主变的设备使用状况。研究发现:主变的空载运行时长远... 详细信息

光伏电站项目的设计规划中,大多数的主变压器容量都较大。通过分析光伏系统每小时的发电数据与环境的温度状况,结合计算可得出主变每小时的热点温度及对应的热老化参数,进而准确模拟主变的设备使用状况。研究发现:主变的空载运行时长远大于满载时长,空载运行呈现低老化状态,可有效弥补满载运行的快速老化状况,且在可控范围内的满载、过载,不会影响主变设备的绝缘性能。高热点温度引发的主变设备早期损害问题,是主变容量优化设计中的主要影响因素,需加以重视。

关键词：光伏项目主变设备热点温度热老化绝缘性能

Analysis on kinematic and inertial interaction in liquefiable soil-pile-structure dynamic system

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Earthquake Engineering and Engineering Vibration 2023年第3期22卷 601-612页

作者： Xu Chengshun Liu Hao dou pengfei Wang Jinting Chen Su Du Xiuli Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100124China Department of Hydraulic Engineering Tsinghua UniversityBeijing 100084China

The dynamic pile-soil interaction in a liquefied site was investigated by means of numerical simulation and shaking table tests in this *** on the results from the shaking table experiment,the cross-correlation analysis of the soil displacement-pile bending moment and superstructure acceleration-pile bending moment was performed to study the influence of kinematic interaction and inertial interaction on the seismic response of piles.A relatively reasonable and accurate finite difference numerical analysis model of liquefiable soil-pile group-superstructure dynamic system was *** numerical simulation,the understanding of kinematic interaction and inertial interaction in the shaking table test was *** mass,damping and period of the superstructure were selected as variables to carry out parameter analysis to further study the influence of inertial interaction on the pile-structure failure *** results show that the influence of kinematic interaction on the pile was much greater than that of inertial *** mass of the superstructure was the most important parameter of inertial interaction,and dynamic characteristics of the superstructure also had an effect on inertial *** effect of inertial interaction on the part near the pile tip was more significant,indicating that the failure near the pile tip is closely related to inertial interaction.

关键词： shaking table experiments pile-supported structures dynamic response liquefaction lateral constraint instability

Seismic response comparison and sensitivity analysis of pile foundation in liquefiable and non-liquefiable soils

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Earthquake Engineering and Engineering Vibration 2023年第1期22卷 87-104页

作者： Jia Kemin Xu Chengshun Du Xiuli Cui Chunyi dou pengfei Song Jia Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of Technology Beijing 100124China Transportation Engineering College Dalian Maritime University Dalian 116026China North China University of Technology School of Civil Engineering Beijing 100144China

Case history investigations have shown that pile foundations are more critically damaged in liquefiable soils than non-liquefiable *** study examines the differences in seismic response of pile foundations in liquefiable and non-liquefiable soils and their sensitivity to numerical model parameters.A two-dimensional finite element(FE)model is developed to simulate the experiment of a single pile foundation centrifuge in liquefiable soil subjected to earthquake motions and is validated against real-world test *** differences in soil-pile seismic response of liquefiable and non-liquefiable soils are ***,the first-order second-moment method(FOSM)is used for sensitivity analysis of the seismic *** results show significant differences in seismic response for a soil-pile system between liquefiable and non-liquefiable *** seismic responses are found to be significantly larger in liquefiable soil than in non-liquefiable ***,the pile bending moment was mainly affected by the kinematic effect in liquefiable soil,while the inertial effect was more significant in non-liquefiable *** controlling parameters of seismic response were PGA,soil density,and friction angle in liquefiable soil,while the pile bending moment was mainly controlled by PGA,the friction angle of soil,and shear modulus of loose sand in non-liquefiable soil.

关键词： liquefiable non-liquefiable finite element analysis pile foundation seismic response sensitivity analysis

Simulation of Hydrodynamic Performance of Drag and double Reverse Propeller Podded Propulsors

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Journal of Marine Science and Application 2016年第1期15卷 16-27页

作者： Chunyu Guo pengfei dou Tao Jing Dagang Zhao School of Shipbuilding Engineering Harbin Engineering University Harbin 150001 China

The unsteady performance of drag and double reverse propeller podded propulsors in open water was numerically simulated using a computational fluid dynamics （CFD） method. A moving mesh method was used to more realistically simulate propulsor working conditions, and the thrust, torque, and lateral force coefficients of both propulsors were compared and analyzed. Forces acting on different parts of the propulsors along with the flow field distribution of steady and unsteady results at different advance coefficients were compared. Moreover, the change of the lateral force and the difference between the abovementioned two methods were mainly analyzed. It was shown that the thrust and torque results of both methods were similar, with the lateral force results having the highest deviation

关键词： podded propulsor propeller lateral force computational fluid dynamics (CFD) hydrodynamic performance moving mesh method

Experimental Study on Hydrodynamics of L-type Podded Propulsor in Straight-ahead Motion and Off-Design Conditions

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Journal of Marine Science and Application 2017年第1期16卷 48-59页

作者： Dagang Zhao Chunyu Guo Yumin Su pengfei dou Tao Jing School of Shipbuilding Engineering Harbin Engineering University Harbin 150001 China National Engineering Research Center of Shanghai ship Design Technology Shanghai 200080 China

Experimental tests were conducted to evaluate the hydrodynamic performance of an L-type podded propulsor in straight-ahead motion and off-design conditions using an open-water measuring instrument developed by the authors for podded propulsors, a ship model towing tank, and under water particle image velocimetry （PIV） measurement systems. Under the three types of conditions, the main parameters of an L-type podded propulsor were measured, including the propeller thrust and torque, as well as the thrust, side force, and moment of the whole pod *** addition, the flow field on the section between the propeller and the strut was analyzed. Experimental results demonstrate that the dynamic azimuthing rate and direction and the turning direction affect the forces on the propeller and the whole pod unit. Forces are asymmetrically distributed between the left and right azimuthing directions because of the effect of propeller rotation. The findings of this study provide a foundation for further research on L-type podded propulsors.

关键词： L-type podded propulsor off-design condition flow field particle image velocimetry propeller hydrodynamic experimental test

Co-aromatization of methane and hexane over Pt encapsulated in ZSM-5 zeolite and the electronic effect of K promoters

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Science China Chemistry 2024年第3期67卷 1017-1027页

作者： Bei Liu Fan Wang Xiaomeng dou pengfei Li Hongwei Xiang Yong Yang Peng He State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China Department of Chemistry Tsinghua UniversityBeijing 100084China National Energy R&D Center for Coal to Liquid Fuels Synfuels China Technology Co.Ltd.Beijing 101407China University of Chinese Academy of Sciences Beijing 101408China Leibniz-Institut für Katalyse e.V.an der Universitat Rostock Rostock 18059Germany

The co-aromatization of methane with higher hydrocarbons represents a promising route to valorize methane, an abundant but underexploited carbon resource. In this study, we elucidate a novel approach to enhance the catalytic co-aromatization of hexane and methane by confining Pt within zeolite catalysts and modulating its electron density. Our findings show that encapsulating Pt within MFI structure is pivotal for activating the feedstock and fostering the formation of aromatic products. Interaction between K atoms and the silanol nest forms siloxy groups which are critical for the stabilization of Pt species. Tuning the K content in PtSn@MFI catalysts adeptly alters the electronic configuration of Pt clusters. This modification is corroborated by infrared and X-ray photoelectron spectroscopy analysis, and density functional theory calculations. Remarkably, the catalyst with 0.8 wt% K exhibits an optimal Pt electron density, driving its superior efficacy in the co-aromatization reaction, converting 0.78 mol of methane for each mole of hexane processed. By employing ~(13)C isotopic labeling and solid-state NMR studies, we demonstrate the participation of methane in the adsorbed species inside the zeolite channel and its incorporation to the benzyl site of the substitute group and phenyl rings in aromatic compounds, underscoring the importance of Pt encapsulation.

关键词： Pt encapsulation MFI zeolite methane activation co-aromatization ^(13)C solid-state NMR

A Study on the Factors influencing insulin resistance in obese adolescents

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Journal of Nanjing Medical University 2008年第6期22卷 391-394页

作者： Yongmei Jin pengfei dou Departments of Pediatrics The First Affiliated Hospital of Anhui Medical University Hefei 230032 Anhui Province China

Objective： To explore the factors influencing insulin resistance in obese Chinese children. Methods： We randomly selected 53 children with uncomplicated obesity between 9 to14 years of age, and 29 normal healthy children, matched for age and sex. Anthropometric and plasma biochemical variables（including lipid profiles, glucose and insulin） were measured using standard methods. We calculated insulin resistance（IR） index using homeostasis model assessment（HOMA） methods and measured plasma high-sensitivity C-reactive protein（hs-CRP） levels using nephelometric methods. All statistical analyses were conducted using the statistical package SPSS. Results： Levels of fasting serum insulin, hs-CRP, total cholesterol（TC）, low density lipoproteins cholesterol（LDL-C） and IR index were higher in obese children than in controls, while high-density lipoprotein cholesterol（HDL-C） values were lower in the obese children. There was no significant difference in levels of fasting blood glucose between the two groups. HOMA-IR was used as the dependent variable in multivariate regression analysis. Significant independent predictors for insulin resistance adjusted for waist/hip ratio, diastolic pressure （DBP）, BMI, triglycerides and HDL-C level were waist circumference（WC）, weight and systolic pressure（SBP）. Conclusion： Waist circumference, weight and SBP are predictors of insulin resistance syndrome in Chinese adolescents

关键词： Obesity Insulin resistance Adolescents

Genetic and biological properties of H9N2 avian influenza viruses isolated in central China from2020 to 2022

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Journal of Integrative Agriculture 2024年第8期23卷 2778-2791页

作者： Libin Liang Yaning Bai Wenyan Huang pengfei Ren Xing Li dou Wang Yuhan Yang Zhen Gao Jiao Tang Xingchen Wu Shimin Gao Yanna Guo Mingming Hu Zhiwei Wang Zhongbing Wang Haili Ma Junping Li College of Veterinary Medicine Shanxi Agricultural UniversityJinzhong 030801China Shanxi Provincial Animal Disease Prevention and Control Center Taiyuan 030000China

The H9N2 subtype of avian influenza virus(AIV)is widely prevalent in poultry and wild birds globally,and has become the predominant subtype circulating in poultry in *** H9N2 AIV can directly or indirectly(by serving as a"donor virus")infect humans,posing a significant threat to public ***,there is a lack of in-depth research on the prevalence of H9N2 viruses in Shanxi Province,central *** this study,we isolated 14 H9N2 AIVs from October 2020 to April 2022 in Shanxi Province,and genetic analysis revealed that these viruses belonged to 7 different *** study on animals revealed that the H9N2 strains we identified displayed high transmission efficiency among chicken populations,and exhibited diverse replication abilities within these *** viruses could replicate efficiently in the lungs of mice,with one strain also demonstrating the capacity to reproduce in organs like the brain and *** the cellular level,the replication ability of different H9N2 strains was evaluated using plaque formation assays and multi-step growth curve assays,revealing significant differences in the replication and proliferation efficiency of the various H9N2 viruses at the cellular *** antigenicity analysis suggested that these isolates could be classified into 2 separate antigenic *** research provides crucial data to help understand the prevalence and biological characteristics of H9N2 AIVs in central *** also highlights the necessity of enhancing the surveillance of H9N2 AIVs.

关键词： avian influenza virus H9N2 central China pathogenicity antigenicity

局部液化夹层场地土-结接触特性对地下结构地震响应的影响研究

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岩石力学与工程学报 2023年第S01期42卷 3643-3653页

作者：闫冠宇许成顺张梓鸿宋佳豆鹏飞北京工业大学城市与工程安全减灾教育部重点实验室北京100124 北方工业大学土木工程学院北京100144 清华大学水利水电工程系北京100084

当地下结构穿越液化土层,场地液化可能会对结构的动力响应产生影响。基于已开展的局部液化夹层场地地下结构离心机振动台模型试验,建立二维局部液化场地土-结构动力相互作用的有限元模型。计算模型考虑砂土液化后易产生剪切大变形的特... 详细信息

当地下结构穿越液化土层,场地液化可能会对结构的动力响应产生影响。基于已开展的局部液化夹层场地地下结构离心机振动台模型试验,建立二维局部液化场地土-结构动力相互作用的有限元模型。计算模型考虑砂土液化后易产生剪切大变形的特点以及饱和两相介质与结构接触的非线性特性,通过与试验结果对比,验证数值模型的正确性,进一步分析土-结构接触非线性特性对结构地震响应的影响。研究结果表明:孔压的增长是由于地震作用的累积效应;近场砂土由于土结相互作用的存在超孔压比上升的更快,且由于土与结构变形不协调而更易消散;对于局部液化夹层场地,土结捆绑接触会放大结构的地震响应,随着地震动强度的增大,砂土层液化程度提高,场地非线性特性增强,土结刚度差异增大,土结界面采用捆绑接触所带来的误差越大,故应合理考虑土结界面接触非线性问题。

关键词：土力学液化场地离心机振动台试验土-结界面模型有限元分析