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SiC逆变器供电的牵引电机匝间绝缘性能评估

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绝缘材料 2024年第4期57卷 88-99页

作者：罗英露赵安然王鹏于超凡林沐泓黄文冬彭增中车株洲电力机车研究所有限公司湖南株洲410002 四川大学电气工程学院四川成都610065

采用碳化硅(SiC)逆变器供电,虽然可以减小牵引变频电机体积、质量、温升,提高电机效率,但逆变器输出电压的高频、短上升时间等特性给牵引变频电机绝缘带来了挑战,尤其是匝间绝缘将会承受更高的电压负荷,导致绝缘过早失效。本文首先通过... 详细信息

采用碳化硅(SiC)逆变器供电,虽然可以减小牵引变频电机体积、质量、温升,提高电机效率,但逆变器输出电压的高频、短上升时间等特性给牵引变频电机绝缘带来了挑战,尤其是匝间绝缘将会承受更高的电压负荷,导致绝缘过早失效。本文首先通过模拟SiC逆变器在最大开关频率及实际电缆线长度下高压变频牵引电机匝间绝缘所承受的电压波形,在不同电压参数(频率、电压峰峰值、上升时间)、不同温度、不同匝间绝缘层厚度(0.23 mm、0.30 mm)下对高压变频电机电磁线进行局部放电起始电压测试及耐电晕寿命测试,并根据牵引电机的实际运行工况和绝缘系统的电负荷失效机理,分析PDIV、局部放电特性及寿命的变化机理。PDIV测试结果表明:频率与上升时间的变化并不会对PDIV产生影响;温度升高,PDIV呈现下降趋势,但由于制作工艺问题,在部分温度下会出现上升趋势;厚度的增加对PDIV提升较大,在考虑成本及效率可控的前提下,提高厚度能有效提高变频电机匝间绝缘能力。耐电晕测试结果表明:温度与上升时间的变化会造成绝缘寿命发生较大改变;频率及电压峰峰值对绝缘寿命的影响呈非线性关系,可用反幂模型表达,并且在工业应用上针对频率对绝缘寿命的影响可直接通过比例关系进行折算。

关键词： SiC逆变器电压参数匝间绝缘层厚度 PDIV 耐电晕寿命

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Tunable quantum dots in monolithic Fabry-Perot microcavities for high-performance single-photon sources

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Light(Science & Applications) 2024年第2期13卷 325-332页

作者： Jiawei Yang Yan Chen Zhixuan Rao Ziyang Zheng Changkun Song yujie Chen Kaili Xiong Pingxing Chen chaofan Zhang Wei Wu Ying yu Siyuan yu State Key Laboratory of Optoelectronic Materials and Technologies School of Electronics and Information TechnologySun Yat-Sen UniversityGuangzhou 510006China Institute for Quantum Science and Technology College of ScienceNational University of Defense TechnologyChangsha 410073China College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 410073China Hunan Key Laboratory of Quantum Information Mechanism and Technology National University of Defense TechnologyChangsha 410073 HunanChina Hefei National Laboratory Hefei 230088China

Cavity-enhanced single quantum dots(QDs)are the main approach towards ultra-high-performance solid-state quantum light sources for scalable photonic quantum technologies.Nevertheless,harnessing the Purcell effect requires precise spectral and spatial alignment of the QDs’emission with the cavity mode,which is challenging for most cavities.Here we have successfully integrated miniaturized Fabry-Perot microcavities with a piezoelectric actuator,and demonstrated a bright single-photon source derived from a deterministically coupled QD within this microcavity.Leveraging the cavity-membrane structures,we have achieved large spectral tunability via strain tuning.On resonance,a high Purcell factor of~9 is attained.The source delivers single photons with simultaneous high extraction efficiency of 0.58,high purity of 0.956(2)and high indistinguishability of 0.922(4).Together with its compact footprint,our scheme facilitates the scalable integration of indistinguishable quantum light sources on-chip,therefore removing a major barrier to the development of solid-state quantum information platforms based on QDs.

关键词： quantum removing purity

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经典肉桂酸合成实验的改进与拓展

大学化学 2024年第5期39卷 243-250页

作者：高庆英罗涛苏建源俞超凡李家柱焉炳飞李文佐张震刘义烟台大学化学化工学院

肉桂酸合成实验是高等学校现行《有机化学实验》教材中的一个重要单列基础实验。该实验在教学实施过程中暴露出残余苯甲醛气味难闻、原料对水敏感、购存困难、高温副产物多等问题。针对以上问题，本论文对经典肉桂酸合成实验进行了改进... 详细信息

肉桂酸合成实验是高等学校现行《有机化学实验》教材中的一个重要单列基础实验。该实验在教学实施过程中暴露出残余苯甲醛气味难闻、原料对水敏感、购存困难、高温副产物多等问题。针对以上问题，本论文对经典肉桂酸合成实验进行了改进：采用苯甲醛/丙二酸/三乙烯二胺的均相反应体系制备肉桂酸，采用亚硫酸氢钠洗涤、萃取的后处理方法去除残余苯甲醛，使其更符合现代实验教学和绿色化学的要求。改进后的实验不仅可有效去除难闻的残余苯甲醛，还具有原料稳定性好、价格低廉、后处理操作简单等优点。通过增加波谱学表征、柱色谱分离等环节，该实验可以拓展为以精细化学品阿魏酸为合成目标的8学时综合性创新实验，提高对学生化学综合素质的培养。

关键词：肉桂酸合成实验亚硫酸氢钠实验创新

Effects of prebiotics on the fermentation of traditional suancai of Northeast China

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Food Science and Human Wellness 2024年第3期13卷 1358-1367页

作者： Mingwei Zhao Xinying Cao yuzheng Wu Sibo Zou Zhigao Li Xinping Lin chaofan Ji Liang Dong Sufang Zhang Chenxu yu Huipeng Liang National Engineering Research Center of Seafood Collaborative Innovation Center of Provincial and Ministerial Co-construction for Deep ProcessingCollaborative Innovation Center of Seafood Deep ProcessingSchool of Food Science and TechnologyDalian Polytechnic UniversityDalian 116034China Department of Agricultural and Biosystems Engineering Iowa State UniversityIA 50011USA

Suancai is a traditional fermented vegetable widely consumed in Northeast China.In this study,different prebiotics were used to improve the quality of suancai.Four prebiotics(inulin(INU),xylooligosaccharide(XO S),galactooligosaccharide(GOS),and stachyose(STA))were shown to reduce the pH value and increase the content of total titratable acidity(TTA)in suancai,while the contents of most organic acids were also increased.The addition of prebiotics had significant effects on the bacterial microbiota during the suancai fermentation process.All prebiotics were shown to contribute to the growth of Lactobacillus.The suancai sample with fructooligosaccharides(FOS)had the highest relative abundance of Lactobacillus.Besides,INU and XOS could increase the abundance of Weissella.To evaluate the quality of suancai fermented with prebiotics,profiles of volatile flavor compounds(VOCs)and free amino acids(FAA)were analyzed.The prebiotics affected the VOCs and FAA profiles via transforming the bacterial microbiota.In addition,the addition of prebiotics also changed the taste profiles of the suancai samples.This study is among the first attempts to reveal the effects of different prebiotics on suancai fermentation,and the findings provide a foundation to develop new ways for improving the quality of suancai.

关键词： Bacterial microbiota Lactic acid bacteria Flavor Amino acid Taste

Effects of phosphorylated ovalbumin on the quality of pork myofibrillar protein gel:an insight into gelling and physicochemical properties

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Journal of Future Foods 2024年第2期4卷 149-158页

作者： Zhihui yu Yating Gao Meng Wu chaofan Zhao Xiubin Liu Xiaoyu Zhang Lixin Zhang Yisheng Chen College of Food Science and Engineering Shanxi Agricultural UniversityTaigu 030801China College of Animal Science and Technology Hunan Agricultural UniversityChangsha 410128China Houji Laboratory in Shanxi Province Shanxi Agricultural UniversityTaiyuan 030031China

This study aimed to investigate the effects of phosphorylated-ovalbumin(P-OVA)at different concentrations(0.5%and 1.0%)on the gel properties of pork myofibrillar protein(MP).The results showed that the textural properties such as gel hardness,cohesiveness,springiness and chewiness were improved with P-OVA addition at 0.5%.The water holding capacity(up to 75.89%)and gel strength(up to 168.56 g·mm)of MP gel were markedly increased after P-OVA addition.The absolute value of zeta potential reached 13.85 mV and maximum hydrophobicity(15.2μg)resulted from the addition of 0.5%P-OVA.The storage modulus(G’)and loss modulus(G’’)of MP gel were significantly increased from 50°C,and the G’and G’’significantly increased after 1.0%P-OVA addition,evidencing that the cross-linking effect of MP protein gel was enhanced.In addition,the P-OVA addition improved the structure of MP gel protein by reducing theα-helix,while increasing theβ-sheet and the r-value(the ratio between two ultraviolet second-derivative peak-to-trough distances),which further promoted the uniform and compact gel network structure.This work demonstrated that P-OVA is a highly effective modifier that significantly improves the quality of MP gel.From a view of practice,0.5%P-OVA is the optimal addition amount.

关键词： Phosphorylated ovalbumin Myofibrillar proteins Gel properties Structures

Probing the Nucleation and Growth Kinetics of Bismuth Nanoparticles via In-situ Transmission Electron Microscopy

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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 877-887页

作者：王浪李超凡 RAN Maojin yuAN Manman 胡执一 LI yu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Nanostructure Research Centre(NRC) Wuhan University of TechnologyWuhan 430070China Institute of Chemistry Henan Academy of SciencesZhengzhou 450002China Henan Academy of Sciences Zhengzhou 450046China

The nucleation and growth mechanism of nanoparticles is an important theory,which can guide the preparation of nanomaterials.However,it is still lacking in direct observation on the details of the evolution of intermediate state structure during nucleation and growth.In this work,the evolution process of bismuth nanoparticles induced by electron beam was revealed by in-situ transmission electron microscopy(TEM)at atomic scale.The experimental results demonstrate that the size,stable surface and crystallographic defect have important influences on the growth of Bi nanoparticles.Two non-classical growth paths including single crystal growth and polycrystalline combined growth,as well as,corresponding layer-by-layer growth mechanism along{012}stable crystal plane of Bi nanoparticles with dodecahedron structure were revealed by in-situ TEM directly.These results provide important guidance and a new approach for in-depth understanding of the nucleation and growth kinetics of nanoparticles.

关键词： bismuth nanoparticles crystal growth transmission electron microscopy in-situ electron microscopy

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阴燃法处理含油污泥的研究及应用进展

化工进展 2023年第7期42卷 3760-3769页

作者：杨子育朱玲王文龙于超凡桑义敏北京石油化工学院环境工程系北京102617

近年来,含油污泥已经成为了威胁全球的危险废物之一,如果未经妥善处置,不但会对环境造成极大的破坏,还会对人体产生危害。阴燃作为一种新型的含油污泥处理技术,很好地契合了资源化、减量化、无害化的含油污泥处理目标。阴燃通过自维持... 详细信息

近年来,含油污泥已经成为了威胁全球的危险废物之一,如果未经妥善处置,不但会对环境造成极大的破坏,还会对人体产生危害。阴燃作为一种新型的含油污泥处理技术,很好地契合了资源化、减量化、无害化的含油污泥处理目标。阴燃通过自维持燃烧处理含油污泥中的污染物,无需外部能源,极大地降低了处理成本,操作简单,二次污染很小。阴燃法不仅能发挥出多种热处理技术的优势,实现含油污泥的减量化,并且还能够回收含油污泥中的部分油分,具有极大的资源化潜力,是一种极具前景的含油污泥处理技术,在国内外均已有成功的工程应用案例。本文对阴燃的原理、研究发展进程及工程应用方面进行了阐述,分别论述了气体流量、污染物浓度、初始含水率、多孔介质掺混比例、土壤粒径对阴燃成功率及含油污泥处理效果的影响,并对该技术的发展方向提出展望。

关键词：含油污泥阴燃法无害化处理影响因素

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基于非监督对比学习的火星地形特征提取方法

北京航空航天大学学报 2024年第6期50卷 1842-1849页

作者：杨博魏翔于贺刘超凡北京航空航天大学宇航学院北京100191

火星表面地形智能识别对火星车自主探测具有重要意义,火星地形图像的特征提取方法目前主要分为传统的浅层视觉特征提取和基于监督学习的深层特征提取2类。找回丢失图像信息、获取大量带标签数据是要解决的关键问题。为此,提出一种基于... 详细信息

火星表面地形智能识别对火星车自主探测具有重要意义,火星地形图像的特征提取方法目前主要分为传统的浅层视觉特征提取和基于监督学习的深层特征提取2类。找回丢失图像信息、获取大量带标签数据是要解决的关键问题。为此,提出一种基于非监督对比学习的火星地形特征识别方法,通过建立图像字典数据集,用“问询”和“编码”2组神经网络分别将单个图像与“字典”数据集中其他图像进行对比,用相似度泛函作为损失函数对网络进行训练,从而实现对火星地形图像的特征识别。所提方法还具有对训练数据集之外的新类型地形图像识别能力,后续识别分类优越性突出。仿真结果表明:所提方法识别准确率为85.4%,对新类型地形图像的识别准确率为84.5%。

关键词：对比学习非监督深度学习火星地形特征提取

重复方波参数对变频电机绝缘放电频域能量分布影响研究

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绝缘材料 2022年第2期55卷 78-83页

作者：于超凡王鹏马世金李佩宜 Shakeel AKRAM 四川大学电气工程学院四川成都610065

采用双极性重复方波电压,借助特高频测试方法,实验研究了重复方波电压幅值、频率、占空比、上升时间对变频电机匝间绝缘放电频域能量分布的影响规律。结果表明:放电0.50 GHz以上频域能量随占空比的增大而明显增加;频域各频段能量随脉冲... 详细信息

采用双极性重复方波电压,借助特高频测试方法,实验研究了重复方波电压幅值、频率、占空比、上升时间对变频电机匝间绝缘放电频域能量分布的影响规律。结果表明:放电0.50 GHz以上频域能量随占空比的增大而明显增加;频域各频段能量随脉冲电压幅值的增大而增加,1.50 GHz以上高频能量随频率的提升不断衰减;脉冲电压上升速率对放电频域能量影响显著,放电脉冲在1.00~2.00 GHz高频能量随电压上升速率的增大而增加。在设计用于高频、陡脉冲电压下变频电机绝缘PDIV测试的特高频传感器时,应充分考虑上述脉冲参数对频域能量的分布影响,以提升PDIV测试的灵敏度和信噪比。

关键词：变频电机局部放电电压幅值占空比上升时间频域能量