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Research on Dynamic and Static Test Methods for Evaluating the Poisson's Ratio of Orien ted Strand Board

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Journal of Renewable Materials 2022年第12期10卷 3459-3476页

作者： Yuhao Zhou yuhang he Zhaoyu Shen Zheng Wang College of Materals Science and Engineering Nanjing Forestry University Nanjing 210037China

In this article,dynamic method and static method of testing Poisson's ratio of OSB(Oriented Strand Board)were *** modal and static numerical analyses,the position where the transverse stress is equal to zero was *** binary linear regression method was applied to express the gluing position of the strain gauge as a relational express ion that depended on the length-width ratio and width-thickness ratio of the canti-lever *** the longitudinal and transverse Poisson's ratios of OSB were mea sured by the given dynamic and static *** addition,the test results of OSB Poisson's ratio were analyzed with the probability distribution of random *** results showed that using the proposed dynamic method and static method,the test results for longitudinal and transverse Poisson's ratios of OSB were quite consistent,despite the gluing position of the strain gauges being *** these OSB Poisson's ratios were accorded with that obtained by the axial tensile method and the four-point bending *** longitudinal and transverse Poisson's ratios followed Weibull distribution.

关键词： OSB Poisson's ratio cantilever plate dynamic test static test

Experimental Mode and Vibration Comfort Analysis of High-Rise Glulam Building Floor Structure

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Journal of Renewable Materials 2023年第6期11卷 2729-2743页

作者： yuhang he Rongzhuo Zhang Yifan Zhang Zheng Wang College of Materials Science and Engineering Nanjing Forestry UniversityNanjing210037China

In order to better meet the objective requirements of the use safety of the high-rise glulam building floor structure and the living comfort of the residents,the transient excitation,environmental excitation and frequency spectrum identification methods were used to carry out experimental modal test in-site on the three rooms numbered A,B and C of the same glulam structural *** three rooms have different functions,different floor sizes and different floor supporting *** research results have shown that the first-order bending frequency of the floor structure of Room A is 27.50 Hz,the transverse second-order bending frequency is 34.75 Hz,the longitudinal second-order bending frequency is 53.25 Hz,and the first-order torsional frequency is 56.25 *** reinforced wooden beam at the bottom of the floor of Room A increases the transverse stiffness of the floor structure,but does not offset the anisotropy caused by the longitudinally installed glulam *** fundamental frequency values of the floor structures of the three rooms numbered A,B,and C are 27.5,13 and 18 Hz,*** has a relatively high innovation and reference significance for integrating the theory of structural dynamic characteristics with the dynamic testing technology,improving the design level of high-rise glulam structure buildings,and improving the living comfort of residents.

关键词： Glulam building wooden floor experimental mode vibration comfort fundamental frequency

Numerical investigation on unsteady characteristics of ducted fans in ground effect

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中国航空学报:英文版 2023年第9期36卷 79-95页

作者： Yiwei LUO Tianfu AI yuhang he Bin XU Yuping QIAN Yangjun ZHANG State Key Laboratory of Automotive Safety and Energy School of Vehicle and MobilityTsinghua UniversityBeijing 100084China Vehicle Research Center School of Mechanical EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401120China

Ducted fans are widely used in various applications of Unmanned Aerial Vehicles(UAVs)due to the high efficiency,low noise and high *** unsteady characteristics of ducted fans flying near the ground are significant,which may bring stability *** this paper,the sliding mesh technology is applied and the Unsteady Reynolds Averaged Navier-Stokes(URANS)method is adopted to evaluate the influence of ground on the aerodynamic performance of ducted *** time-averaged results show that the ground leads to the decrease of duct thrust,the increase of rotor thrust and the decrease of total *** transient results show that there exist small-scale stall cells with circumferential movements in ground *** stall cells start to appear at the blade root when the height is 0.8 rotor radius distance,and arise at both the blade root and tip when the height drops to *** is found that the unsteady cells rotate between blade passages with an approximate relative speed of 30%-80%of the fan speed,and lead to thrust fluctuations up to 37%of the total *** results are essential to the flight control design of the ducted fan flying vehicle,to ensure its stability in ground effect.

关键词： Computational fluid dynamics Ducted fan Ground effect Thrust fluctuations UAV

Measurement and Analysis of Three-Dimensional Surface Topography of Sawn Timber Based on Scanning Probe Method

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Journal of Renewable Materials 2022年第12期10卷 3303-3311页

作者： yuhang he Rongzhuo Zhang Sarah Mohrmann Zheng Wang Jiujin Fang Jiangsu Co-Innovation Center of Efcient Processing and Utilization of Forest Resources College of Materials Science and TechnologyNanjing Forestry UniversityNanjing210037China College of Civil Engineering Nanjing Forestry UniversityNanjing210037China College of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing210037China

In order to explore the characteristics of the three-dimensional surface morphology of sawn timber,a three-dimensional wood surface morphology tester based on the scanning probe method and the principle of atomic force microscope was used to test the three-dimensional sur face morphology of three kinds of sawn timber and calculate its surface *** study also analyzed the reasonable plan for the value of wood surface roughness and the advantages of the three dimensional shape tester,as well as the influence of tree species,three sections,air dry density and other factors on the surface roughness of the specimen after mechanical *** results have shown that it is a more appropriate method to select the calculated values of S。and Sq as the evaluation of the surface roughness of wood with random surface *** three dimensional wood surface topo-graphy tester can efficiently,conveniently and accurately display the three dimensional topography of wood at a micron-level resolution,and is characterized by high eficiency and good *** three dimensional surface morphology characteristics of the three sawn woods correspond to their *** surface roughness of woods is arranged as follows:Sitka spruce>Larch>*** the same tree species,the roughness of the corresponding section after sawing is as follows:chordwise section>crosswise section>radial *** radial section has lower roughness than the other *** surface roughness of the wood after sawing is mainly related to its air-dry *** above is intended to provide a useful reference for the application of measuring and evaluating the surface roughness of sawn timber using the three dimensional surface topography test method.

关键词： Scanning probe sawn timber three dimensional topography test surface roughness

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电网友好性低碳建筑能源系统评价方法研究

浙江建筑 2024年第2期41卷 81-84页

作者：胡佳敏梁利霞何宇航杨银琛浙江省建筑科学设计研究院有限公司浙江杭州310012 建筑绿色低碳技术浙江省工程研究中心浙江杭州310012 浙江建科节能环保科技有限公司浙江杭州310012

在“双碳”和电力需求侧改革的背景下,电网友好性低碳建筑成为未来建筑发展趋势,但目前仍未形成成熟的设计及评价体系。通过分析电网友好性低碳建筑能源系统评价影响因素,总结提炼评价指标,并采用层次分析法确定各指标权重,建立低碳建... 详细信息

在“双碳”和电力需求侧改革的背景下,电网友好性低碳建筑成为未来建筑发展趋势,但目前仍未形成成熟的设计及评价体系。通过分析电网友好性低碳建筑能源系统评价影响因素,总结提炼评价指标,并采用层次分析法确定各指标权重,建立低碳建筑能源系统电网友好性评价方法,可为该类项目建设提供设计指导和评价依据,并做到以评促推,有利于电网友好性低碳建筑的示范和推广。

关键词：电网友好性低碳建筑能源系统层次分析法综合评价指标

大尺寸铝合金轮毂双边浇注低压铸造工艺的模拟及优化

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特种铸造及有色合金 2024年第4期44卷 484-489页

作者：周振卢德宏何宇航李向明逯东辉李贞明刘建高昆明理工大学材料与科学工程学院昆明月650500 云南富源今飞轮毂制造有限公司富源原655007

为解决大尺寸铝合金轮毂低压铸造中心浇工艺存在的轮辐处晶粒粗大和缩松等问题,提出双边浇工艺,并采用ProCAST软件对双边浇空冷工艺下的充型和凝固过程进行有限元模拟。基于模拟结果,采用水冷工艺减小了双边浇工艺的缺陷,并进行了验证... 详细信息

为解决大尺寸铝合金轮毂低压铸造中心浇工艺存在的轮辐处晶粒粗大和缩松等问题,提出双边浇工艺,并采用ProCAST软件对双边浇空冷工艺下的充型和凝固过程进行有限元模拟。基于模拟结果,采用水冷工艺减小了双边浇工艺的缺陷,并进行了验证。结果表明,在合适的水冷条件下,双边浇工艺能消除轮辐处的缺陷,提高力学性能。

关键词：低压铸造铝合金轮毂工艺优化

Design and Development of Composite Plywood that Integrates Fire Resistance,Water Resistance and Wear Resistance

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Journal of Renewable Materials 2023年第5期11卷 2333-2344页

作者： Xingyu Liang Xiaoyu Gu Myint Myint Paing Hsu yuhang he Rongzhuo Zhang Conghui Cai Zheng Wang College of Materials Science and Engineering Nanjing Forestry UniversityNanjing210037China College of Civil Engineering Nanjing Forestry UniversityNanjing210037China Jiangsu Shancong Wood Co. Ltd.Lianyungang222505China

In order to improve the fire resistance,water resistance and wear resistance of ordinary plywood products in the wood processing industry,three composite structures of plywood products S1,S2 and S3 were designed in this paper,and a reasonable production process was *** the physical and mechanical properties and fire resistance testing and technical and economic analysis,the applicability of composite plywood was *** results of the study showed that the physical mechanics of the three kinds of composite structure plywood met the standard requirements,and their fire resistance was far better than that of ordinary *** them,the S1 structural board had the best overall physical and mechanical *** S3 structural board showed the best fire resistance,which was about 1.9 times more than that of ordinary plywood,and the added cost was the *** thin cork board added to the S2 structural board had poor fire performance since the air in the cork board cavities had a certain combustion-supporting effect,which inhibited the fire resistance of high-pressure laminate(HPL)***,the additional cost of the S2 board was the highest,and its comprehensive performance was the *** S3 structural plywood product composed of HPL fireproof board with a thickness of about 1 mm in the surface layer and ordinary plywood with a thickness of about 12 mm in the core layer was the most cost-effective product,which could meet the needs of various fields such as construction,home furnishing,decoration and transportation.

关键词： Wear resistance plywood structural design and development physical and mechanical properties fire resistance

How do the landslide and non-landslide sampling strategies impact landslide susceptibility assessment? d A catchment-scale case study from China

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 877-894页

作者： Zizheng Guo Bixia Tian yuhang Zhu Jun he Taili Zhang School of Civil and Transportation Engineering Hebei University of TechnologyTianjin300401China hebei Key Laboratory of Earthquake Disaster Prevention and Risk Assessment Sanhe065201China Faculty of Engineering China University of GeosciencesWuhan430074China Nanjing Center China Geological SurveyMinistry of Natural ResourcesNanjing210016China

The aim of this study is to investigate the impacts of the sampling strategy of landslide and non-landslide on the performance of landslide susceptibility assessment(LSA).The study area is the Feiyun catchment in Wenzhou City,Southeast *** types of landslides samples,combined with seven non-landslide sampling strategies,resulted in a total of 14 *** corresponding landslide susceptibility map(LSM)for each scenario was generated using the random forest *** receiver operating characteristic(ROC)curve and statistical indicators were calculated and used to assess the impact of the dataset sampling *** results showed that higher accuracies were achieved when using the landslide core as positive samples,combined with non-landslide sampling from the very low zone or buffer *** results reveal the influence of landslide and non-landslide sampling strategies on the accuracy of LSA,which provides a reference for subsequent researchers aiming to obtain a more reasonable LSM.

关键词： Landslide susceptibility Sampling strategy Machine learning Random forest China

The study of lithographic variation in resistive random access memory

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Journal of Semiconductors 2024年第5期45卷 69-79页

作者： yuhang Zhang Guanghui he Feng Zhang Yongfu Li Guoxing Wang Department of Micro-Nano Electronics Shanghai Jiao Tong UniversityShanghai 200240China MoE Key Lab of Artificial Intelligence Shanghai Jiao Tong UniversityShanghai 200240China Institute of Microelectronics Chinese Academy of SciencesBeijing 100029China

Reducing the process variation is a significant concern for resistive random access memory(RRAM).Due to its ultrahigh integration density,RRAM arrays are prone to lithographic variation during the lithography process,introducing electrical variation among different RRAM *** this work,an optical physical verification methodology for the RRAM array is developed,and the effects of different layout parameters on important electrical characteristics are systematically *** results indicate that the RRAM devices can be categorized into three clusters according to their locations and lithography *** read resistance is more sensitive to the locations in the array(~30%)than SET/RESET voltage(he increase in the RRAM device length and the application of the optical proximity correction technique can help to reduce the variation to less than 10%,whereas it reduces RRAM read resistance by 4×,resulting in a higher power and area *** such,we provide design guidelines to minimize the electrical variation of RRAM arrays due to the lithography process.

关键词： layout lithography process variation resistive random access memory