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Improved Stiffness Modeling for An Exechon‑Like Parallel Kinematic Machine(PKM)and Its Application

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Chinese Journal of Mechanical Engineering 2020年第3期33卷 130-141页

作者： Nanyan Shen Liang geng Jing Li Fei ye Zhuang Yu Zirui Wang Shanghai Key Laboratory of Intelligent Manufacturing and Robotics Shanghai UniversityShanghai 200444China School of Mechatronic Engineering and Automation Shanghai UniversityShanghaiChina.

Hole drilling or contour milling for the large and complex workpieces such as automobile panels and aircraft fuselages makes a high combined demand on machining accuracy,stiffness and workspace of machining ***,a 5-DOF(degrees of freedom)parallel kinematic machine(PKM)with redundant constraints is *** on the kinematics analysis of the parallel mechanism using intermediate variables,the kinematics problems of the PKM are solved through equivalent kinematics *** structural stiffness matrix method is adopted to model the stiffness of the parallel mechanism of the PKM,where the stiffness of each joint and branch component is obtained by stiffness formula and finite element *** the stiffness model of the parallel mechanism is improved by correction coefficient matrix,each element of which is constructed as a polynomial function of three independent end variables of the parallel *** terminal stiffness matrices obtained by simulation result are used to determine the coefficients of polynomial function by least square fitting to describe the correction coefficient over the workspace of the parallel mechanism *** experiment results prove that the modification method can greatly improve the stiffness model of the parallel *** enhance the machining accuracy of the PKM,the proposed kinematics model and the improved stiffness model are utilized to optimize the working stiffness of parallel machine by searching the best relative position of parallel machine and workpiece.A plate workpiece taken as example is examined in the case study section,which demonstrates the effectiveness of optimization method.

关键词： PKM 5-DOF Equivalent kinematics model Intermediate variables Stiffness correction coefficient Optimal working stiffness

针对海上风电场汇集线路单相接地故障的柔直侧新型距离保护方案

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中国电机工程学报 2024年第15期44卷 5899-5907,I0005页

作者：晁晨栩郑晓冬叶海刘中平刘虎林韩俊张怀宇邰能灵电力传输与功率变换控制教育部重点实验室(上海交通大学) 上海市闵行区200240 国家电网有限公司华东分部上海市浦东新区200120 国家电网有限公司西南分部四川省成都市610095

海上风电场汇集线路发生单相接地故障时,线路两侧短路电流分别由风电机组换流器和柔直换流器提供,由于正序、负序与零序网络串联,在传统大电网存在场景下不受控制影响的零序电流也将像正序和负序电流一样呈现幅值受限、相位受控特性,柔... 详细信息

海上风电场汇集线路发生单相接地故障时,线路两侧短路电流分别由风电机组换流器和柔直换流器提供,由于正序、负序与零序网络串联,在传统大电网存在场景下不受控制影响的零序电流也将像正序和负序电流一样呈现幅值受限、相位受控特性,柔直侧距离保护无法正确识别单相接地故障。该文建立海上风电场汇集线路单相接地故障时的复合序网,分析汇集线路两侧故障特性,在不借助线路双端通信的前提下,利用柔直侧负序和零序电流准确求取风机侧零序电流。基于此,构建关于故障距离的方程,提出柔直侧新型距离保护方案,解决了双端均为逆变型电源的线路中零序电流受控导致距离保护性能下降的问题。此外,所提保护方案受风电场无功支撑策略、过渡电阻大小及性质影响小。测试结果表明,该保护方案可以准确识别海上风电场汇集线路区内外单相接地故障。

关键词：海上风电场柔性直流换流站汇集线路距离保护单相接地故障过渡电阻

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基于剩磁技术的管道应力解析方法研究

化工设备与管道 2024年第2期61卷 95-102页

作者：田野陈海艳阙永彬高涛王国庆耿浩国家管网集团西部管道有限责任公司乌鲁木齐830063 沈阳工业大学信息科学与工程学院沈阳110870

油气管道是国家重要的能源基础设施,管道的受力状态是影响管道安全运行的重要因素。对管道应力的有效检测可以预知管道破坏的风险。以铁磁性材料微观磁学理论为基础,建立应力与材料剩磁场之间的数学模型,分析了剩磁与应力之间的对应关系... 详细信息

油气管道是国家重要的能源基础设施,管道的受力状态是影响管道安全运行的重要因素。对管道应力的有效检测可以预知管道破坏的风险。以铁磁性材料微观磁学理论为基础,建立应力与材料剩磁场之间的数学模型,分析了剩磁与应力之间的对应关系,对不同应力作用下铁磁性材料的剩磁效应进行了解析。通过有限元软件对应力与剩磁之间的关系进行了仿真分析。结果表明,应力与剩磁信号之间具有线性对应关系,铁磁性材料的磁滞回线随应力增大而偏移,在较低应力范围内,剩余磁场强度随应力增大而增大,之后随应力增大呈线性下降趋势,剩磁随应力的变化趋势存在一个反转点。通过对管道材料进行受力拉伸试验,验证了理论分析的正确性。

关键词：应力剩磁效应管道有限元

A New Conservative Allen-Cahn Type Ohta-Kawaski Phase-Field Model for Diblock Copolymers and Its Numerical Approximations

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Advances in Applied Mathematics and Mechanics 2022年第1期14卷 101-124页

作者： Shuang geng Tongmao Li Qiongwei ye Xiaofeng Yang College of Management Shenzhen UniversityShenzhenGuangdong 518060China Business School Yunnan University of Finance and EconomicsKunmingYunnan 650221China Department of Mathematics University of South CarolinaColumbiaSC 29208USA

We develop a new conservative Allen-Cahn phase-field model for diblock copolymers in this paper by using the Allen-Cahn type gradient flow approach for the classical Ohta-Kawaski free *** change in volume fraction of two composing monomers is eliminated by using a nonlocal Lagrange *** on the recently developed stabilized Scalar Auxiliary Variable method,we have further developed an effective numerical scheme to solve the *** scheme is highly efficient and only two linear and decoupled equations are needed to solve at every time *** then prove that the numerical method is unconditionally energy stable,the stability and accuracy of the new scheme are demonstrated by numerous numerical examples *** qualitatively comparing the equilibrium solution obtained by the new model and the classic Cahn-Hilliard model,we illustrate the effectiveness of the new model.

关键词： Phase-field Diblock copolymer Allen-Cahn nonlocal second order unconditional energy stability

考虑多运行场景的城市电网用户侧储能需求评估方法

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浙江电力 2024年第2期43卷 96-104页

作者：李伟周天董绍光叶丽雅赵能能何杲杳耿光超国网浙江省电力有限公司培训中心杭州310015 浙江大学电气工程学院杭州310027 国网浙江省电力有限公司余姚市供电公司浙江余姚315400

在城市电网中配置用户侧储能是解决可再生能源消纳能力不足、局部过载等运行问题的有效途径之一。因此,提出了一种考虑多运行场景的城市电网储能需求评估方法。通过出现频率与危害性来量化城市电网不同场景间的权重构成,选取正常运行、... 详细信息

在城市电网中配置用户侧储能是解决可再生能源消纳能力不足、局部过载等运行问题的有效途径之一。因此,提出了一种考虑多运行场景的城市电网储能需求评估方法。通过出现频率与危害性来量化城市电网不同场景间的权重构成,选取正常运行、可再生能源消纳不足、局部过载场景构建城市电网用户侧储能需求评估模型。使用浙江省某区域城市电网37节点模型进行算例分析,结果表明该方法能够有效地评估城市电网用户侧储能需求,提高用户侧储能在不同运行场景下的复用率,与单运行场景储能需求评估方法相比,能够显著减少城市电网的用户侧储能总需求,并节约其投资与运行成本。

关键词：多运行场景城市电网用户侧储能需求评估

Incidence and prognosis of olfactory and gustatory dysfunctions related to SARS-CoV-2 Omicron strain infection in China:A national multicenter survey of 35,566 individuals

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World Journal of Otorhinolaryngology-Head and Neck Surgery 2024年第2期10卷 113-120页

作者： Meng-Fan Liu Rui-Xia Ma Xian-Bao Cao Hua Zhang Shui-Hong Zhou Wei-Hong Jiang Yan Jiang Jing-Wu Sun Qin-tai Yang Xue-Zhong Li Ya-Nan Sun Li Shi Min Wang Xi-Cheng Song Fu-Quan Chen Xiao-Shu Zhang Hong-Quan Wei Shao-Qing Yu Dong-Dong Zhu Luo Ba Zhi-Wei Cao Xu-Ping Xiao Xin Wei Zhi-Hong Lin Feng-Hong Chen Chun-Guang Shan Guang-Ke Wang Jing ye Shen-Hong Qu Chang-Qing Zhao Zhen-Lin Wang Hua-Bin Li Feng Liu Xiao-Bo Cui Sheng-Nan ye Zheng Liu Yu Xu Xiao Cai Wei Huang Ru-Xin Zhang Yu-Lin Zhao Guo-Dong Yu Guang-Gang Shi Mei-Ping Lu Yang Shen Yu-Tong Zhao Jia-Hong Pei Shao-Bing Xie Long-Gang Yu ye-Hai Liu Shao-Wei Gu Yu-Cheng Yang Lei Cheng Jian-Feng liu Graduate School of Beijing University of Chinese Medicine BeijingChina Department of Otorhinolaryngology Head and Neck Surgery China-Japan Friendship HospitalBeijingChina Department of Otorhinolaryngology Head and Neck Surgery The First People's Hospital of YinchuanYinchuanChina Department of Otorhinolaryngology The First People's Hospital of Yunnan ProvinceKunmingChina Department of Otorhinolaryngology The First Affiliated Hospital of Xinjiang Medical UniversityUrumqiChina Department of Otorhinolaryngology Head and Neck Surgery The First Affiliated Hospital of Zhejiang University School of MedicineHangzhouChina Department of Otorhinolaryngology Head and Neck Surgery Xiangya Hospital Central South UniversityChangshaChina Department of Otorhinolaryngology Head and Neck Surgery The Affiliated Hospital of Qingdao UniversityQingdaoChina Department of Otorhinolaryngology Head and Neck Surgery The First Affiliated Hospital of USTCHefeiChina Department of Otorhinolaryngology Head and Neck Surgery The Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhouChina Department of Otorhinolaryngology Head and Neck Surgery Qilu Hospital of Shandong UniversityJinanChina Department of Otorhinolaryngology Head and Neck Surgery The Second Affiliated Hospital of Harbin Medical UniversityHarbinChina Department of Otolaryngology The Second Hospital of Shandong UniversityShandong UniversityJinanChina Department of Otorhinolaryngology Head and Neck Surgery Peking University People's HospitalBeijingChina Department of Otorhinolaryngology Head and Neck Surgery Yantai Yuhuangding HospitalQingdao UniversityYantaiChina Department of Otorhinolaryngology Head and Neck Surgery Xijing HospitalThe Fourth Military Medical UniversityXi'anChina Gansu Provincial Center for Disease Control and Prevention LanzhouChina Department of Otorhinolaryngology Head and Neck Surgery The First Affiliated Hospital of China Medical UniversityShenyangChina Department of Otorhinolaryngology Head and Neck Surgery Tongji Hospit

Objective:This cross-sectional study aimed to determine the epidemiology of olfactory and gustatory dysfunctions related to COVID-19 in ***:This study was conducted by 45 tertiary Grade-A hospitals in *** and offline questionnaire data were obtained from patients infected with COVID-19 between December 28,2022,and February 21,*** collected information included basic demographics,medical history,smoking and drinking history,vaccination history,changes in olfactory and gustatory functions before and after infection,and other postinfection symptoms,as well as the duration and improvement status of olfactory and gustatory ***:Complete questionnaires were obtained from 35,566 *** overall incidence of olfactory and taste dysfunction was 67.75%.Being female or being a cigarette smoker increased the likelihood of developing olfactory and taste *** received four doses of the vaccine or having good oral health or being a alcohol drinker decreased the risk of such *** infection,the average olfactory and taste VAS scores were 8.41 and 8.51,respectively;after infection,they decreased to 3.69 and 4.29 and recovered to 5.83 and 6.55 by the time of the *** median duration of dysosmia and dysgeusia was 15 and 12 days,respectively,with 0.5%of patients having symptoms lasting for more than 28 *** overall self-reported improvement rate was 59.16%.Recovery was higher in males,never smokers,those who received two or three vaccine doses,and those that had never experienced dental health issues,or chronic accompanying ***:The incidence of dysosmia and dysgeusia following infection with the SARS-CoV-2 virus is high in *** and prognosis are influenced by several factors,including sex,SARS-CoV-2 vaccination,history of head-facial trauma,nasal and oral health status,smoking and drinking history,and the persistence of accompanying symptoms.

关键词： epidemiologic studies incidence olfactory disorders prognosis SARS-CoV-2 taste disorders

Calculation aided miscibility manipulation enables highly efficient polythiophene:nonfullerene photovoltaic cells

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Science China Chemistry 2021年第3期64卷 478-487页

作者： Qi Wang Miaomiao Li Zhongxiang Peng Nigel Kirby Yunfeng Deng Long ye Yanhou geng Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityFuzhou 350207China School of Materials Science and Engineering Tianjin UniversityTianjin 300072China Tianjin Key Laboratory of Molecular Optoelectronic Science Tianjin UniversityCollaborative Innovation Center of Chemical Science and Engineering(Tianjin)Tianjin 300072China Australian Synchrotron ClaytonVictoria 3168Australia State Key Laboratory of Luminescent Materials and Devices South China University of TechnologyGuangzhou 510640China

Polythiophenes,with merits of low cost and high scalability of synthesis,have received growing interest in organic solar *** date,the best-performing polythiophene:nonfullerene solar cells exhibit typical power conversion efficiencies (PCEs) of 10%–12%,which is much lower than those employing PM6-and D18-type *** inferior performance is mostly limited by the improper miscibility between polythiophene and *** on engineering the molecular structure to systematically tune the miscibility are *** the aid of group contribution calculations,the miscibility of polythiophene:nonfullerene blend system was finely tuned by varying the ratios of siloxane-terminated chains and alkyl chains in ester-substituted polythiophenes through random *** on a series of the polythiophene and nonfullerene acceptors,the detailed analysis of blend miscibility and performance reveals a surprising anticorrelation between the Flory-Huggins interaction parameter (χ_(aa)) and the optimal time of solvent vapor annealing for device performance across these *** due to the slightly higher χ_(aa),the blend of PDCBT-Cl-Si5 and ITIC-Th1 results in a record-high PCE of 12.85%in polythiophene:nonfullerene solar *** results not only provide a calculation-guided approach for molecular design but also prove that precise control of the miscibility is an effective way to design high-performance polythiophene:nonfullerene blends and beyond.

关键词： nonfullerene organic solar cells polythiophenes miscibility molecular design

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香葱染色体核型分析

种子 2024年第1期43卷 102-106页

作者：李胜辉杨也廖国会张素勤赵兴艺耿广东贵州大学农学院贵阳550025 贵州省植物保护研究所贵阳550006

为探索香葱染色体核型特点,采用滴片技术获得3个香葱品种的根尖细胞染色体片子,并进行染色体核型分析。结果表明,3个香葱品种均为二倍体,染色体数目为2n=2x=16,平坝白葱的染色体较赫章黑葱和赫章红葱粗短,呈近椭圆形。赫章黑葱的核型公... 详细信息

为探索香葱染色体核型特点,采用滴片技术获得3个香葱品种的根尖细胞染色体片子,并进行染色体核型分析。结果表明,3个香葱品种均为二倍体,染色体数目为2n=2x=16,平坝白葱的染色体较赫章黑葱和赫章红葱粗短,呈近椭圆形。赫章黑葱的核型公式为2n=2x=14 m+2 sm, 16条染色体中臂比大于2的染色体占总染色体数的12.5%,核型不对称系数为59.06%,核型类型为2A;赫章红葱的核型公式为2n=2x=12 m+4 sm, 16条染色体中臂比大于2的染色体占总染色体数的12.5%,核型不对称系数为59.16%,核型类型为2A;平坝香葱的核型公式为2n=2x=14 m+2 st, 16条染色体中臂比大于2的染色体占总染色体数的12.5%,核型不对称系数为57.10%,核型类型为2A。3个品种中进化程度最高的是赫章红葱,最低的是平坝白葱。

关键词：香葱染色体核型分析

Gelation capability of cysteine-modified cyclo(L-Lys-L-Lys)s dominated by Fmoc and Trt protecting groups

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Science China Chemistry 2016年第3期59卷 293-302页

作者： Huimin geng Qianying Zong Jie You Lin ye Aiying Zhang Ziqiang Shao Zengguo Feng School of Materials Science and Engineering Beijing Institute of Technology

A series of symmetrical peptidomimetics （3-8） based on cysteine-modified cyclo（L-Lys-L-Lys）s were synthesized, and their gelation capability in organic solvents was dominated by fluorenylmethyloxycarbonyl （Fmoc） and triphenylmethyl （Trt） protecting groups and the exchange of thiol-to-disulfide as well. The peptidomimetics holding Trt （3 and 4） showed no gel performance, while the Fmoc groups promoted 5 and 6 to give rise to thermo-reversible organogels in a number of organic solvents. The self-assembled fibrillar networks were distinctly evidenced in the organogels by transmission electron micros- copy （TEM） and scanning electron microscopy （SEM） observations. Fourier transform infrared spectroscopy （FT-IR） and fluorescence analyses revealed that the hydrogen bonding and ^-rt stacking play as major driving forces for the self-assembly of these organogelators. A 13-turn secondary structure was deduced for the organogel of 6 by virtue of X-ray diffraction, FT-IR and circular dichroism （CD） measurements, and an interdigitated bilayer structure was also presented.

关键词： organogel cyclic dipeptide self-assembly cysteine β-turn