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预氧化聚丙烯腈纳米纤维膜声学性能研究

纺织工程学报 2024年第1期2卷 44-54页

作者：王宇孙凯旋黄庆林天津工业大学材料科学与工程学院天津300387 天津工业大学分离膜与膜过程国家重点实验室天津300387

通过对静电纺丝聚丙烯腈(PAN)纳米纤维膜进行预氧化处理,制备了声学性能优异的预氧化聚丙烯腈(OPAN)纳米纤维膜。研究了纳米纤维直径和孔隙率对声学性能的影响,结果表明:OPAN纳米纤维膜在全频率范围(1 k~10 kHz)内的声损值为-2.01 dB~+3... 详细信息

通过对静电纺丝聚丙烯腈(PAN)纳米纤维膜进行预氧化处理,制备了声学性能优异的预氧化聚丙烯腈(OPAN)纳米纤维膜。研究了纳米纤维直径和孔隙率对声学性能的影响,结果表明:OPAN纳米纤维膜在全频率范围(1 k~10 kHz)内的声损值为-2.01 dB~+3.12 dB,且随着纳米纤维直径的增加,声损值呈增大的趋势。为了提高OPAN纳米纤维膜的模量,在PAN纳米纤维膜中引入了聚酰胺酸(PAA),在PAN预氧化的同时,PAA被热亚胺化,最终得到OPAN/PI纳米纤维膜。当OPAN/PI质量比为7∶3时,纳米纤维膜具有最高的杨氏模量(2000.07 MPa)和最低的声损值1.24 dB(1000 Hz)。此外,与OPAN纳米纤维膜相比,OPAN/PI纳米纤维膜因其杨氏模量更高,在低频(100-1000 Hz)范围内声损值更低。

关键词： OPAN PI 静电纺丝纳米纤维膜声学性能

Study on operation voltage monitoring and electrothermal coupling simulation of electric multiple unit(EMU)roof arrester

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High Voltage 2022年第2期7卷 357-368页

作者： Qizhe Zhang Shenghui Wang kaixuan sun Xinghao Dong Mingliang Liu Fangcheng Lü State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijingChina Hebei Provincial Key Laboratory of Power Transmission Equipment Security Defense North China Electric Power UniversityBaodingChina

The roof arrester of electric multiple units(EMU)can efficiently limit the overvoltage,and ensure the safe operation of the EMU electrical *** the process of high‐speed operation,the traction power supply system is often affected by *** addition,roof arrester explosion accidents occasionally *** this paper,the on‐line voltage measurement system of the EMU arrester is *** analysing a large number of voltage waveforms,the abnormal voltage is divided into three categories:over‐phase voltage,high harmonic voltage and steep impulse *** charac-teristics of abnormal voltage waveforms are then *** electrothermal coupling simulation model of the arrester is developed,and the current response and temperature distribution of the arrester under abnormal voltage are *** impact of the impulse voltage energy on the arrester temperature is studied by applying a triangular wave voltage to the ***,some suggestions are proposed for the operation and maintenance of the roof arrester.

关键词： operation traction coupling

短切纤维特性对间位芳纶纸电气绝缘性能的影响

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绝缘材料 2024年第2期57卷 19-28页

作者：阮浩鸥律方成孙凯旋宋景萱常小斌樊思迪新能源电力系统国家重点实验室(华北电力大学) 北京102206 赣州龙邦材料科技有限公司江西赣州341999

本文研究了短切纤维特性对间位芳纶纸击穿强度、电导率、陷阱特性和力学相关性能的影响。结果表明,在参照样品(直径为25μm、长度为6 mm、结晶温度为300℃、沉析纤维与短切纤维的配比为7∶3)的基础上,纤维直径增加至45μm会降低沉析对... 详细信息

本文研究了短切纤维特性对间位芳纶纸击穿强度、电导率、陷阱特性和力学相关性能的影响。结果表明,在参照样品(直径为25μm、长度为6 mm、结晶温度为300℃、沉析纤维与短切纤维的配比为7∶3)的基础上,纤维直径增加至45μm会降低沉析对短切纤维的包覆程度,诱发界面孔隙,芳纶纸的击穿强度和拉伸强度降幅可达16%和24%;纤维长度增加至18 mm,会造成短切纤维翘曲并形成“硬质”界面,击穿强度降幅可达63%,拉伸强度则无明显变化;结晶温度降低至230℃,会降低短切纤维结构稳定性,导致其热压熔融,击穿强度和拉伸强度降幅可达36%和50%;当短切纤维配比增加时,芳纶纸的击穿强度随致密度呈先升后降趋势,拉伸强度则随短切纤维含量的增加单调递增,体现了短切纤维对芳纶纸稳定成型的必要性和过量短切纤维对绝缘的削弱作用。此外,低击穿强度芳纶纸会呈现电导率提高和电荷陷阱浅化的现象,可作为芳纶纸绝缘性能判别的参考指标。

关键词：间位芳纶纸短切纤维击穿强度电荷陷阱

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首次冻融胚胎移植周期临床结局的影响因素

中国医科大学学报 2024年第9期53卷 793-797页

作者：孙凯旋修银玲王英华张伊彤陆晓黎周静于月新中国人民解放军北部战区总医院生殖医学科沈阳110003

目的分析在首次行冻融胚胎移植的患者中,影响冻融胚胎移植(FET)周期临床妊娠率和活产率的因素。方法回顾性分析1458例首次行FET周期助孕患者的临床数据,根据是否临床妊娠,分为临床妊娠组和未临床妊娠组;根据是否获得活产,分为活产组和... 详细信息

目的分析在首次行冻融胚胎移植的患者中,影响冻融胚胎移植(FET)周期临床妊娠率和活产率的因素。方法回顾性分析1458例首次行FET周期助孕患者的临床数据,根据是否临床妊娠,分为临床妊娠组和未临床妊娠组;根据是否获得活产,分为活产组和未活产组。比较取卵时女方年龄、移植时女方年龄、体重指数、子宫内膜准备方案、子宫内膜厚度、胚胎移植数目和形态等临床数据,分析影响FET周期临床妊娠率和活产率的因素,并将这些因素纳入多因素logistic回归分析,确定影响FET周期临床妊娠率和活产率的独立因素。结果在1458个周期中,临床妊娠率为44.0%,活产率为34.0%。临床妊娠组和活产组移植时女方平均年龄分别明显小于未临床妊娠组和未活产组(P<0.05)。年龄<35岁患者的临床妊娠率和活产率均明显高于年龄≥35岁患者(P<0.05)。子宫内膜厚度≥8 mm患者的临床妊娠率和活产率均明显高于子宫内膜厚度<8 mm患者(P<0.05)。子宫内膜准备方案为自然周期的临床妊娠率明显高于激素替代周期(P<0.05)。2个胚胎移植的临床妊娠率和活产率均明显高于单胚胎移植(P<0.05)。囊胚移植的临床妊娠率和活产率均明显高于卵裂期胚胎移植(P<0.05)。多因素logistic回归分析发现,移植时女方年龄、子宫内膜厚度、移植胚胎数目和移植胚胎形态是FET周期临床妊娠率和活产率的独立影响因素。结论FET周期移植时女方年龄、子宫内膜厚度、移植胚胎数目和移植胚胎形态是临床妊娠和活产结局的独立影响因素。

关键词：辅助生殖技术冻融胚胎移植临床妊娠率活产率

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工业大麻类受体激酶基因家族生物信息学分析

黑龙江科学 2024年第6期15卷 5-8页

作者：曹焜孙宇峰赵越朱浩王盼孙凯旋王晓楠黑龙江省科学院大庆分院黑龙江大庆163319

工业大麻RLK基因家族在碱性盐胁迫响应过程中有重要的调控作用。为探究工业大麻RLK基因家族响应NaHCO_(3)胁迫的信号转导机制,利用生物信息学方法对工业大麻63个RLK基因家族成员进行分析,结果表明,工业大麻的RLK基因家族可分为12个亚组... 详细信息

工业大麻RLK基因家族在碱性盐胁迫响应过程中有重要的调控作用。为探究工业大麻RLK基因家族响应NaHCO_(3)胁迫的信号转导机制,利用生物信息学方法对工业大麻63个RLK基因家族成员进行分析,结果表明,工业大麻的RLK基因家族可分为12个亚组。分析了RLK基因家族在不同盐碱耐受性品种中的表达模式及潜在的生物学功能,此试验结果为进一步研究工业大麻RLK基因家族在逆境响应和生长发育过程中的分子功能提供重要依据。

关键词：工业大麻 RLK基因家族盐碱胁迫生物信息学分析

Flexible artificial synapse based on single-crystalline BiFeO_(3) thin film

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Nano Research 2022年第3期15卷 2682-2688页

作者： Zhen Zhao Amr Abdelsamie Rui Guo Shu Shi Jianhui Zhao Weinan Lin kaixuan sun Jingjuan Wang Junling Wang Xiaobing Yan Jingsheng Chen Key Laboratory of Brain-like Neuromorphic Devices and Systems of Hebei Province College of Electron and Information EngineeringHebei UniversityBaoding 071002China Department of Materials Science and Engineering Nanyang Technological UniversitySingapore 639798Singapore Department of Materials Science and Engineering National University of SingaporeSingapore 117576Singapore Department of Physics Southern University of Science and TechnologyShenzhen 518055China

Realization of functional flexible artificial synapse is a significant step toward neuromorphic ***,a flexible artificial synapse based on ferroelectric tunnel junctions(FTJs)is demonstrated,using BiFeO_(3)(BFO)thin film as the functional *** inorganic single crystalline FTJs grown on rigid perovskite substrates at high temperatures are integrated with the flexible plastic substrates,by using the water-soluble Sr_(3)Al_(2)O_(6)(SAO)as the sacrificial layer and the following *** transferred freestanding BFO thin film exhibits excellent ferroelectric ***,the memristive properties and the brain-like synaptic learning performance of the flexible FTJs are *** results show that multilevel resistance states were maintained well of the flexible artificial synapse,together with their stable synaptic learning *** work indicates the promising opportunity of ferroelectric thin film based flexible synapse used in the future neuromorphic computing system.

关键词： flexible ferroelectricity memristor artificial synapse

Self-cleaning effect and secondary swirling clean gas for suppressing particle deposition on vortex finder of gas cyclones

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Particuology 2024年第7期90卷 72-87页

作者： Zhanpeng sun Huandi Yang kaixuan Zhang Zhiyuan Wang Zhenyuan Hong Guang Yang School of Mechanical Engineering Hebei University of Science&TechnologyShijiazhuang050018China

In order to suppressing the particle deposition on vortex finder,a series of gas cyclones with the secondary swirling clean gas were developed inspired by the gas purge *** of the width and extension length of the flow channel as well as the secondary inlet velocity and running time on the particle deposition pattern,the deposited particle mass and the cyclones'performance were experimentally investigated,*** results show that the ultrafine particles(Stokes number Stk<0.0358)are mainly loose deposited on the walls under the secondary *** to the conventional cyclone with single tangential inlet,the total deposited particle mass of the improved cyclone has a maximum reduction more than 60%,and the collecting efficiency is increased up to 97.5%under the basically same pressure *** corresponding no-deposition area is increased by about 13%,and remains constant in spite of extending the running ***,an interesting phenomenon named"self-cleaning effect"of the vortex finder was captured for the gas cyclones,and mechanism of the secondary clean gas on the particle deposition is preliminarily *** results can deepen the understanding of the particle deposition on the vortex finder and guide the design of the anti-coking gas cyclones.

关键词： Cyclones Vortex finder Particle deposition Gas purge effect Self-cleaning effect

Transfer-free chemical vapor deposition graphene for nitride epitaxy: challenges, current status and future outlook

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Science China Chemistry 2024年第3期67卷 824-840页

作者： Xiang Gao Senlin Li Jingfeng Bi kaixuan Zhou Meng Li Zhongfan Liu Jingyu sun College of Energy Soochow Institute for Energy and Materials InnovationsSUDA-BGI Collaborative Innovation CenterKey Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu ProvinceSoochow UniversitySuzhou 215006China Beijing Graphene Institute Beijing 100095China Xiamen Silan Advanced Compound Semiconductor Co.Ltd. Xiamen 361026China

Graphene, a two-dimensional material with outstanding electrical and mechanical properties, has attracted considerable attention in the field of semiconductor technologies due to its potential use as a buffer layer for the epitaxial Ⅲ-nitride growth. In recent years, significant progress has been made in the chemical vapor deposition growth of graphene on various insulating substrates for the nitride epitaxy, which offers a facile, inexpensive, and easily scalable methodology. However, certain challenges are still present in the form of producing high-quality graphene and achieving optimal interface compatibility with Ⅲ-nitride *** this review, we provide an overview of the bottlenecks associated with the transferred graphene fabrication techniques and the state-of-the-art techniques for the transfer-free graphene growth. The present contribution highlights the current progress in the transfer-free graphene growth on different insulating substrates, including sapphire, quartz, SiO_(2)/Si, and discusses the potential applications of transfer-free graphene in the Ⅲ-nitride epitaxy. Finally, it includes the prospects of the transfer-free graphene growth for the Ⅲ-nitride epitaxy and the challenges that should be overcome to realize its full potential in this field.

关键词： Transfer-free chemical vapor deposition graphene for nitride epitaxy challenges current status and future outlook graphene

工业大麻miR156基因家族在NaHCO_(3)胁迫下的表达模式及生物信息学分析

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中国麻业科学 2024年第1期46卷 10-15,46页

作者：曹焜孙宇峰张晓艳赵越边境朱浩王盼韩承伟孙凯旋王晓楠黑龙江省科学院大庆分院黑龙江大庆163319

工业大麻miR156基因家族在碱性盐胁迫响应过程中发挥重要的调控作用,为探究工业大麻miR156基因家族响应NaHCO_(3)胁迫的分子机制,以盐碱耐受型工业大麻品种火麻一号为供试材料,利用生物信息学和qRT-PCR方法,对miR156基因家族进行分析。... 详细信息

工业大麻miR156基因家族在碱性盐胁迫响应过程中发挥重要的调控作用,为探究工业大麻miR156基因家族响应NaHCO_(3)胁迫的分子机制,以盐碱耐受型工业大麻品种火麻一号为供试材料,利用生物信息学和qRT-PCR方法,对miR156基因家族进行分析。结果表明,工业大麻miR156家族基因与芦笋、野草莓、苹果和大豆的亲缘关系较近。2条工业大麻pre-miR156序列,产生一条相同的miR156成熟体,且成熟体的保守性较高。在NaHCO_(3)胁迫后的24 h内,工业大麻miR156基因表达量随胁迫时间的延长呈先升高后降低再升高的趋势。该结果为进一步研究工业大麻miR156基因家族及其靶基因的调控网络提供理论依据。

关键词：工业大麻 miR156基因家族 NaHCO_(3)胁迫