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Switchable shape memory polymer bio-inspired adhesive and its application for unmanned aerial vehicle landing

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Chinese Journal of Aeronautics 2024年第3期37卷 380-390页

作者： Qingsong HE Zefang ZHAO Qiyun ZHONG Siyuan LIU Kai DENG Yongqi LIU Ning zhanG Zijie ZHAO Fengjiang zhan jianfeng ZHAO Jiangsu Provincial Key Laboratory of Bionic Functional Materials College of Mechanical and Electrical EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Advanced Technology for Small and Medium-Sized UAV Ministry of Industry and Information TechnologyUnmanned Aerial Vehicles Research InstituteNanjing University of Aeronautics and AstronauticsNanjing 210016China State Key Laboratory of Mechanics and Control of Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Functional Morphology and Biomechanics Institute of ZoologyKiel UniversityKiel 24098Germany

Controlled and switchable adhesion is commonly observed in biological systems.In recent years,many scholars have focused on making switchable bio-inspired adhesives.However,making a bio-inspired adhesive with high adhesion performance and excellent dynamic switching properties is still a challenge.A Shape Memory Polymer Bio-inspired Adhesive(SMPBA)was successfully developed,well realizing high adhesion(about 337 kPa),relatively low preload(about90 kPa),high adhesion-to-preload ratio(about 3.74),high switching ratio(about 6.74),and easy detachment,which are attributed to the controlled modulus and contact area by regulating temperature and the Shape Memory Effect(SME).Furthermore,SMPBA exhibits adhesion strength of80–337 kPa on various surfaces(silicon,iron,and aluminum)with different roughness(Ra=0.021–10.280)because of the conformal contact,reflecting outstanding surface adaptability.The finite element analysis verifies the bending ability under different temperatures,while the adhesion model analyzes the influence of preload on contact area and adhesion.Furthermore,an Unmanned Aerial Vehicle(UAV)landing device with SMPBA was designed and manufactured to achieve UAV landing on and detaching from various surfaces.This study provides a novel switchable bio-inspired adhesive and UAV landing method.

关键词： Bio-inspired adhesive Shape memory polymers Switchable adhesive Unmanned aerial vehicle Landing

Changes in Polyphenols and Antioxidant Activities of Yingshan Yunwu Tea during Digestion in Vitro

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Medicinal Plant 2024年第2期15卷 21-25页

作者： Ruyi ZHENG Jinjie ZHOU Wenzhuo WU jianfeng zhan Peng WU Ting DING Weixin WANG College of Biology and Agricultural Resources Huanggang Normal UniversityHubei Collaborative Innovation Center for the Characteristic Resources Exploitation of Dabie MountainsHubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive UtilizationHuanggang 438000China Hubei Hongan County Public Inspection and Testing Center Huanggang 438000China

[Objectives]To explore the change rule of polyphenol content and antioxidant activity of coarse old leaves of Yingshan Yunwu Tea in the process of human digestion.[Methods]The coarse and old leaves of Yunwu tea in Yingshan,Huanggang,Hubei Province were selected as the research object,and their digestion in vitro was simulated.The total polyphenol content was determined by Folin-phenol reagent colorimetric method,and the DPPH radical scavenging activity and total antioxidant activity were determined.[Results]After simulated gastrointestinal digestion in vitro,the polyphenol content and antioxidant activity of coarse old leaf tea soup showed a downward trend.After gastrointestinal digestion,the polyphenol content in tea infusion separately decreased by 31.8%and 8.5%;the scavenging rate of DPPH free radical was 97%before digestion,decreased to 92%after gastric digestion and 65%after intestinal digestion,which decreased by 5%and 27%,respectively;after gastrointestinal digestion,the total antioxidant capacity of tea soup decreased by 4.7%and 3.1%,respectively.[Conclusions]This study provided a reference for the development and application of coarse old leaves of Yingshan Yunwu tea,and provided a reference for the nutritional value evaluation and comprehensive utilization of coarse old leaves,so as to make the best use of coarse tea leaves and reduce the waste of resources.

关键词： Coarse old leaves of Yunwu tea Polyphenol Digestion in vitro Antioxidant activity

基于网格化数值天气预报的区域光伏发电多输出功率预测方法

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中国电力 2024年第3期57卷 144-151页

作者：战文华车建峰王勃丁禹国网内蒙古东部电力有限公司赤峰供电公司内蒙古赤峰024000 可再生能源并网全国重点实验室(中国电力科学研究院有限公司) 北京100192

区域光伏的短期功率预测是省级及以上电网调控中心制定发电计划、提高光伏消纳率的重要基础之一。光伏短期功率预测本质上是构建数值天气预报与实际功率之间的映射模型,为了实现预测精度的提升,利用网格化的数值天气预报,采用残差网络... 详细信息

区域光伏的短期功率预测是省级及以上电网调控中心制定发电计划、提高光伏消纳率的重要基础之一。光伏短期功率预测本质上是构建数值天气预报与实际功率之间的映射模型,为了实现预测精度的提升,利用网格化的数值天气预报,采用残差网络建立区域光伏的多输出预测模型,充分挖掘区域光伏所属空间的气象资源分布与各光伏电站功率的关联关系,实现以网格化数值天气预报为输入的区域各光伏电站的功率预测。以实际运行数据进行仿真,结果表明,本文方法在各光伏电站的功率和总功率2个方面的预测结果均优于现有成熟方法。

关键词：光伏功率预测网格化数值天气预报残差网络多输出模型

Characterizing big data analytics workloads on POWER8 SMT processors

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High Technology Letters 2017年第3期23卷 245-251页

作者：贾禛 zhan jianfeng Wang Lei zhang Lixin State Key Laboratory of Computer Architecture Institute of Computing Technology Chinese Academy of Sciences Beijing 100080 P. R. China University of Chinese Academy of Sciences Beijing 100049 P. R. China

Big data analytics is emerging as one kind of the most important workloads in modern data centers. Hence,it is of great interest to identify the method of achieving the best performance for big data analytics workloads running on state-of-the-art SMT( simultaneous multithreading) processors,which needs comprehensive understanding to workload characteristics. This paper chooses the Spark workloads as the representative big data analytics workloads and performs comprehensive measurements on the POWER8 platform,which supports a wide range of multithreading. The research finds that the thread assignment policy and cache contention have significant impacts on application performance. In order to identify the potential optimization method from the experiment results,this study performs micro-architecture level characterizations by means of hardware performance counters and gives implications accordingly.

关键词：数据分析工作负载处理器 SMT 特征并发多线程硬件性能计数器最佳性能

PhiBench 2.0: characterizing data analytics workloads on Intel Knights Landing

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High Technology Letters 2019年第2期25卷 121-128页

作者：解壁伟 zhan jianfeng Wang Lei zhang Lixin Institute of Computing Technology Chinese Academy of SciencesBeijing 100190P.R.China University of Chinese Academy of Sciences Beijing 100049P.R.China

With high computational capacity, e.g. many-core and wide floating point SIMD units, Intel Xeon Phi shows promising prospect to accelerate high-performance computing(HPC) applications. But the application of Intel Xeon Phi on data analytics workloads in data center is still an open question. Phibench 2.0 is built for the latest generation of Intel Xeon Phi(KNL, Knights Landing), based on the prior work PhiBench(also named BigDataBench-Phi), which is designed for the former generation of Intel Xeon Phi(KNC, Knights Corner). Workloads of PhiBench 2.0 are delicately chosen based on BigdataBench 4.0 and PhiBench 1.0. Other than that, these workloads are well optimized on KNL, and run on real-world datasets to evaluate their performance and scalability. Further, the microarchitecture-level characteristics including CPI, cache behavior, vectorization intensity, and branch prediction efficiency are analyzed and the impact of affinity and scheduling policy on performance are investigated. It is believed that the observations would help other researchers working on Intel Xeon Phi and data analytics workloads.

关键词： Intel Xeon Phi data analytics workloads characterization Knights Landing(KNL) many core x86 processors

Scalable group management in large-scale virtualized clusters

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High Technology Letters 2011年第3期17卷 263-271页

作者： Zhou Wei Wang Lei Meng Dan Yuan Lin zhan jianfeng Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 P. R. China Bureaus of High-Tech Research and Development Chinese Academy of Sciences Beijing 100864 P. R. China

To save cost, more and more users choose provision resources at the granularity of virtual machines in cluster systems, especially data centres. Maintaining a consistent member view is the foundation of reliable cluster managements, and it also raises several challenge issues for large scale cluster systems deployed with virtual machines (which we call virtualized clusters). In this paper, we introduce our experience in design and implementation of scalable member view management on large-scale virtual clusters. Our research contributions include three-aspects: 1) we propose a scalable and reliable management infrastructure that combines a peer-to-peer structure and a hierarchy structure to maintain a consistent member view in virtual clusters; 2) we present a light-weighted group membership algorithm that can reach the consistent member view within a single round of message exchange; 3) we design and implement a scalable membership service that can provide virtual machines and maintain a consistent member view in virtual clusters. Our work is verified on Dawning 5000A, which ranked No.10 of Top 500 super computers in November, 2008. Copyright © by HING TECHNOLOGY LETTERS PRESS.

关键词：集群系统集群管理虚拟化可扩展层次结构基础设施超级计算机虚拟机

高压电缆半导电屏蔽材料双逾渗网络对电阻率稳定性的影响

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中国电机工程学报 2024年第12期44卷 5011-5020,I0034页

作者：贾利川曾剑峰侯帅展云鹏傅明利赵莉华四川大学电气工程学院四川省成都市610065 南方电网科学研究院有限责任公司广东省广州市510663

半导电屏蔽材料是制造高压电缆的关键组分,但仍存在电阻率高及其稳定性差难题。基于此,该文提出构筑双逾渗网络结构思路,选择乙烯-丙烯酸丁酯共聚物(ethylene-butyl acrylate copolymer,EBA)和低密度聚乙烯(low density polyethylene,LD... 详细信息

半导电屏蔽材料是制造高压电缆的关键组分,但仍存在电阻率高及其稳定性差难题。基于此,该文提出构筑双逾渗网络结构思路,选择乙烯-丙烯酸丁酯共聚物(ethylene-butyl acrylate copolymer,EBA)和低密度聚乙烯(low density polyethylene,LDPE)作为基体、导电炭黑(conductive carbon black,CB)作为导电填料制备半导电屏蔽材料,系统研究半导电屏蔽材料结构演变规律,评价半导电屏蔽材料结晶行为、电学性能、力学性能、表面光洁度等关键性能。实验结果表明:EBA与LDPE质量比为6:4时,半导电屏蔽材料内部形成双逾渗导电网络结构,相比于常规分布结构,其23和90℃的体积电阻率分别降低46.7%和74.4%,对应的正温度系数(positive temperature coefficient,PTC)降低52.1%,表明具有良好的电阻率稳定性。此外,该半导电屏蔽材料还具有优异的力学性能和表面光洁度。该结果可为高压电缆半导电屏蔽材料开发提供一定理论基础与数据支撑。

关键词：高压电缆半导电屏蔽材料双逾渗网络低密度聚乙烯乙烯-丙烯酸丁酯共聚物

油蜡热处理对木材物理性能及尺寸稳定性的影响

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森林工程 2024年第1期40卷 106-113页

作者：蒋金成李璟张镜元王秉泉战剑锋东北林业大学材料科学与工程学院哈尔滨150040

为探究植物油蜡热处理对不同树种木材的物理性能及尺寸稳定性的影响,以臭冷杉、落叶松和条纹乌木为研究对象,自主配置的植物油蜡溶液为加热介质,分别在不同温度(140、170、200℃)下对木材进行4 h的高温热处理,再通过充分的冷却确保植物... 详细信息

为探究植物油蜡热处理对不同树种木材的物理性能及尺寸稳定性的影响,以臭冷杉、落叶松和条纹乌木为研究对象,自主配置的植物油蜡溶液为加热介质,分别在不同温度(140、170、200℃)下对木材进行4 h的高温热处理,再通过充分的冷却确保植物油蜡完全进入木材内部,并利用扫描电镜观察其内部结构。研究结果表明,室温冷却阶段是木材油蜡热处理的关键,该阶段植物油蜡大量进入木材内部,这主要表现为木材试件增重百分比(Weight Percentage Gain,WPG)的变化。经植物油蜡联合热处理后,3种木材最大颜色变化(ΔE^(*))分别为48.24、40.67、5.95;表面疏水性均有稳定提高,接触角(Water Contact Angle,WCA)稳定提升至70°左右;不同树种的弦向、径向线湿胀率及体积膨胀率均有不同程度的降低,抗膨胀效率(Anti Swelling Efficiency,ASE)有效提高,3种木材最大提高49.64%、48.24%、38.86%,说明植物油蜡热处理可以提升木材尺寸稳定性。

关键词：植物油蜡热处理木材物理性能尺寸稳定性

保温时间对钛合金板翅式换热器真空钎焊过程温度场及残余应力的影响

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焊接学报 2024年第2期45卷 33-40,I0004,I0005页

作者：李悦王建峰马龙飞杜春辉胡凤娇占小红南京航空航天大学南京211106 中国机械总院集团北京机电研究所有限公司北京100083

钛合金板翅式换热器成品率较低、残余应力较大,该文针对钛合金板翅结构真空钎焊过程开展热-固耦合建模与仿真研究,阐述了钎焊过程温度均匀性及残余应力分布特征,探明保温时间对钛合金板翅式换热器真空钎焊过程温度场及残余应力的影响机... 详细信息

钛合金板翅式换热器成品率较低、残余应力较大,该文针对钛合金板翅结构真空钎焊过程开展热-固耦合建模与仿真研究,阐述了钎焊过程温度均匀性及残余应力分布特征,探明保温时间对钛合金板翅式换热器真空钎焊过程温度场及残余应力的影响机理.结果表明,板翅结构两侧温度较高,中部温度较低,延长保温时间可有效改善板翅结构的温度均匀性.残余应力均主要集中于翅片上表面与隔板背侧中部,在钎缝及夹持点处存在明显的应力集中现象,保温时间越长翅片钎缝的残余应力越小.模拟得到钛合金板翅式换热器真空钎焊中残余应力与试验结果相吻合,相对误差为5.3%,验证了该模型的准确性.

关键词：板翅式换热器钛合金真空钎焊热-固耦合仿真