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Science China(Information Sciences) 2024年第2期67卷 267-278页

作者： guofang yu Renrong LIANG Haiming ZHAO Lei XIAO Jie CUI yue ZHAO Wenpu CUI Jing WANG Jun XU Jun FU Tianling REN School of Integrated Circuits Tsinghua University Beijing National Research Center for Information Science Technology Tsinghua University

Surface acoustic wave(SAW) resonators with an ultrahigh Q-factor are designed and fabricated on silicon-based gallium nitride(GaN/Si). The temperature-dependent performance is characterized over a wide range, from 10 to 500 K. Finite element analysis is employed to guide the design of the SAW resonator from indications of the Rayleigh mode and weak propagation direction dependence of SAW in the c-plane of GaN/Si. The SAW resonator with 100 pairs of interdigital transducers(IDT), 100 pairs of grating reflectors(GR) for each side, aperture size of 80 μm, metallization ratio of 0.5, and electrode width of 500 nm resonates at 1.9133 GHz accordingly with an ultrahigh Q-factor of 7622 at room temperature, which contributes the fr× Qr, up to 14.583×1012Hz. A resonator operating over 10 to 500 K indicates an approximately linear decreasing temperature dependence above 280 K while being approximately constant below 40 K. The fitting to resonator characteristics using the modified Butterworth Van Dyke(m BVD) model reveals a reduction in both the electrode and mechanical losses while worsening the dielectric loss with cooling down.

关键词： GaN/Si SAW resonator ultrahigh Q-factor temperature-dependent performance mBVD losses

Operation of silicon-germanium heterojunction bipolar transistors with different structures at deep cryogenic temperature

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Science Bulletin 2019年第7期64卷 469-477页

作者： guofang yu Renrong Liang Xiawa Wang Jun Xu Tian-Ling Ren Institute of Microelectronics Tsinghua University Beijing National Research Center for Information Science and Technology (BNRist) Tsinghua University

In this work, the device performances of discrete and integrated SiGe heterojunction bipolar transistors(HBTs) with different device structures from 300 to 4.8 K were investigated. The turn-on voltages of baseemitter and base-collector junctions increased non-linearly with temperature cooled to 4.8 K. Energy bandgap engineering was taken into account for the analytical model of the turn-on voltage versus temperature. Incomplete ionization occurred in the base-collector junction because of the low doping concentration. The trap-assisted tunneling current in the forward base current was clearly observed below20 K. The ideality factor and saturation current were shown to be temperature dependence. The ideality factor was much larger than 2 below 40 K, indicating that the current is not only contributed by drift, diffusion and recombination, but also by tunneling. The peak current gain of the discrete SiGe HBTs achieved the maximum value of 3,388 at 80 K, while that of the integrated was 546 at 140 K. The transconductance in logarithm was linearly dependent on reciprocal temperature above 50 K, but flattened below 50 *** effect was evidently observed below 77 K in the fixed base current output characteristics of the discrete SiGe HBTs, and it was not obvious for the integrated SiGe HBTs.

关键词： SiGe HBTs Quantum computing Cryogenic temperature Analytical model

Quasi-Solid-State Composite Electrolytes with Multifunctional 2D Molecular Brush Fillers for Long-Cycling Lithium Metal Batteries

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Chinese Journal of Chemistry 2023年第21期41卷 2848-2854页

作者： Yin Cui guofang yu Ruliang Liu Dongtian Miao Dingcai Wu PCFM Lab School of ChemistrySun Yat-sen UniversityGuangzhouGuangdong510006 China School of Chemistry and Materials Science Guangdong University of EducationGuangzhouGuangdong510303 China

The ever-growing demand for next-generation high-energy-density devices drives the development of lithium metal batteries with enough safety and high performance,in which quasi-solid-state composite electrolytes(QSCEs)with high ionic conductivity and lithium ion transference number(urn:x-wiley:1001604X:media:cjoc202300232:cjoc202300232-math-0001)are highly ***,we successfully synthesize a kind of two-dimensional(2D)molecular brush(GO-g-PFIL)via grafting poly(ionic liquid)side-chain(poly(3-(3,3,4,4,4-pentafluorobutyl)-1-vinyl-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide),denoted as PFIL)on the surface of 2D graphene oxide(GO)***-g-PFIL is used as multifunctional filler to prepare novel composite membranes and corresponding QSCEs(e.g.,QSCE-PH/GPFIL3/P).The as-obtained QSCE-PH/GPFIL3/P integrates features of PFIL side-chain-enhanced lithium ion conduction,poly(vinylidene fluoride-co-hexafluoropropene)backbone-induced flexibility,and GO-strengthened mechanical *** a result,our ultrathin(21μm)self-supporting QSCE-PH/GPFIL3/P exhibits high ionic conductivity(3.24×10^(−4)S·cm^(−1))and excellent urn:x-wiley:1001604X:media:cjoc202300232:cjoc202300232-math-0002(0.82)at room temperature,and Li/LFP full cell with QSCE-PH/GPFIL3/P shows superior rate performance(high specific capacities of 79 mAh·g^(−1)at 30°C and 5 C)and excellent cycling performance(high capacity retention of 91%after 500 cycles at 80°C and 1 C).

关键词： Quasi-solid-state composite electrolyte I Filler 2D molecular brush Lithium metal battery Poly(ionic liquid)

基于定量泵闭式冷却塔橡胶机械冷却系统的设计

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橡塑技术与装备 2024年第6期50卷 70-73页

作者：赵承芳郭娜于国芳杨俊敬中车石家庄车辆有限公司河北石家庄051430 石家庄财经职业学院河北石家庄051430

本文针对我公司金属橡胶件再制造项目,利用定量泵闭式冷却塔,对橡胶机械设备循环冷却水进行了设计研究,并对本系统一些关键项点进行了分析探讨,经投入使用及生产验证,本系统能够满足橡胶机械设备生产使用要求,为同类项目定量泵闭式冷却... 详细信息

本文针对我公司金属橡胶件再制造项目,利用定量泵闭式冷却塔,对橡胶机械设备循环冷却水进行了设计研究,并对本系统一些关键项点进行了分析探讨,经投入使用及生产验证,本系统能够满足橡胶机械设备生产使用要求,为同类项目定量泵闭式冷却塔循环冷却系统的设计提供了参考。

关键词：闭式冷却塔定量泵橡胶机械循环冷却系统

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煤矸区分中的间隔灰度压缩扩阶共生矩阵

中国图象图形学报 2012年第8期17卷 966-970页

作者：于国防中国矿业大学信电学院徐州221116

为了有效提高共生矩阵惯性矩在图像纹理分析及检索中的作用,在常规纹理分析方法的基础上,研究了一种基于间隔灰度压缩的扩阶共生矩阵惯性矩。该方法采用对原图像的灰度信息进行部分压缩和部分保留的综合处理方式,并通过矩阵的扩阶提取... 详细信息

为了有效提高共生矩阵惯性矩在图像纹理分析及检索中的作用,在常规纹理分析方法的基础上,研究了一种基于间隔灰度压缩的扩阶共生矩阵惯性矩。该方法采用对原图像的灰度信息进行部分压缩和部分保留的综合处理方式,并通过矩阵的扩阶提取未压缩的灰度信息,达到灰度信息随机与有序兼容利用的效果。实验结果表明,该算法比基于图像全局灰度压缩的常规共生矩阵惯性矩具有更大的目标类型区分度,其目标区分正确率大于82%,也更容易设置相应的区分阈值,而且具有较高的图像分析实时性。

关键词：块煤与矸石区分图像纹理间隔灰度压缩扩阶共生矩阵惯性矩

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媒体融合——“大象”如何“跳街舞”

电视研究 2019年第7期 57-61页

作者：虞国芳上海大学新闻传播学院

将我国如火如荼的媒体融合实践比喻成“大象跳街舞”,在当下现实情境中可谓再形象不过。媒体融合实现“大象跳街舞”,需要做好资源整合,重塑媒体格局;内容为王,打造核心竞争力;移动优先,优化生产流程;技术驱动,提升用户体验。媒体融合... 详细信息

将我国如火如荼的媒体融合实践比喻成“大象跳街舞”,在当下现实情境中可谓再形象不过。媒体融合实现“大象跳街舞”,需要做好资源整合,重塑媒体格局;内容为王,打造核心竞争力;移动优先,优化生产流程;技术驱动,提升用户体验。媒体融合是一次凤凰涅槃,痛过之后就是新生。

关键词：媒体融合资源整合内容为王移动优先技术驱动

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压缩型顶点链码的研究

中国图象图形学报 2010年第10期15卷 1465-1470页

作者：于国防王莉中国矿业大学信电学院徐州221116

提出了两种新的压缩型顶点链码的编码方法。根据图像边界的顶点链码中通常包含大量的两个顶点的连续编号的特点,用0和9分别代替常规顶点链码的1和3,而用1到8这8个数字直接表示连续出现率最高的编号2及其数量,研究了一种动态顶点链码。... 详细信息

提出了两种新的压缩型顶点链码的编码方法。根据图像边界的顶点链码中通常包含大量的两个顶点的连续编号的特点,用0和9分别代替常规顶点链码的1和3,而用1到8这8个数字直接表示连续出现率最高的编号2及其数量,研究了一种动态顶点链码。将链码顶点分为1、2、3和1与3的组合4种类型,用一个字节的高位区和低位区分别表示链码编号及其连续数量,研究了一种压缩型顶点链码。结合一种编码综合效率评价方法,通过与现有的链码进行比较,结果表明本文所研究的链码不仅具有50%～70%的编码压缩比,而且编码或解码的效率也提高了10%～40%,即具有更好的实时性。

关键词：顶点链码动态顶点链码压缩型链码综合效率