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一种抑制连续换相失败的定关断角加速控制方法

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电力系统保护与控制 2024年第4期52卷 56-66页

作者：王玉麟李晓华李昊李书勇郑艺欣华南理工大学电力学院广东广州510641 中国南方电网科学研究院有限责任公司广东广州510663

针对逆变侧交流故障引发高压直流输电系统连续换相失败问题,通过分析首次换相失败恢复过程中的电气量和控制量变化规律,明确了恢复过程中定电流、定关断角、电流偏差控制器之间配合不当是引发连续换相失败的重要原因。同时,在不对称故障... 详细信息

针对逆变侧交流故障引发高压直流输电系统连续换相失败问题,通过分析首次换相失败恢复过程中的电气量和控制量变化规律,明确了恢复过程中定电流、定关断角、电流偏差控制器之间配合不当是引发连续换相失败的重要原因。同时,在不对称故障后,由交流负序电流引起的直流2.谐波电流会导致控制切换点滞后,增加连续换相失败的风险。基于此,提出了一种能增强控制器配合效果的定关断角加速控制方法。该方法能根据换相恢复过程自适应投切,利用关断角偏差动态调整关断角控制指令值,提前实现控制切换,降低切换后不当控制影响。同时,通过陷波器降低谐波电流从而减弱触发角波动对控制器切换的不利影响。该方法能提升控制器间配合效果,提升直流系统抵御连续换相失败能力。在CIGRE标准测试模型中,验证了理论分析的正确性和优化方法的有效性。

关键词：连续换相失败控制器配合不当定关断角控制负序电流

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响应性胶体晶体反射光谱预测模型及实验验证

光学学报 2024年第4期44卷 346-354页

作者：张金英王鑫野司玉琳王炳楠杨佳兴张野效桐精密光电测试仪器及技术北京市重点实验室北京理工大学光电学院北京100081 北京理工大学长三角研究院浙江嘉兴314001

建立了一种以面心立方三维光子晶体为基础的有限元预测模型,研究了纳米粒子折射率、溶剂折射率、粒子直径、粒子间距等参数对反射光谱的影响。根据预测结果制备了优化尺寸的Fe_(3.O_(4)@SiO_(2.纳米粒子电调谐器件。结果表明,有限元模... 详细信息

建立了一种以面心立方三维光子晶体为基础的有限元预测模型,研究了纳米粒子折射率、溶剂折射率、粒子直径、粒子间距等参数对反射光谱的影响。根据预测结果制备了优化尺寸的Fe_(3.O_(4)@SiO_(2.纳米粒子电调谐器件。结果表明,有限元模型预测的反射光谱中心波长在680 nm至455 nm范围内移动,与制备器件的测试光谱匹配性良好。与解析预测模型相比,建立的三维有限元预测模型得到的反射光谱中心波长的预测结果准确性更高。对于非核壳结构,两种模型的预测误差范围分别为0.49%~1.70%、0.82.~1.49%,表现相当;对于核壳结构,两种模型的预测误差范围分别为3.51%~6.11%、0.2.%~1.3.%。本文建立的三维有限元模型将预测误差典型值降低为原来的1/5.9。所提模型可用于准确预测胶体体系下自组装光子晶体反射光谱的动态调谐能力,弥补了解析预测模型在核壳结构光子晶体预测准确性方面的不足,可指导粒子材料参数和结构参数设计,以及可调谐范围的优化区间筛选。对反射光谱幅值和谱宽预测准确性的提升需进一步考虑短程有序结构等随机微扰特性的影响。

关键词：光谱学胶体体系自组装光子晶体动态变色器件有限元预测模型反射光谱中心波长

Tilted Perpendicular Anisotropy-Induced Spin-Orbit Ratchet Effects

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chinese Physics Letters 2024年第7期41卷 181-186,I0001,I0002,I0003页

作者：陈彬龙垣图聂宇林凌姿瑀马天平张瑞轩吴义政骆泳铭王宁宁 School of Electronics and Information Engineering Hangzhou Dianzi UniversityHangzhou 310018China State Key Laboratory of Surface Physics and Department of Physics Fudan UniversityShanghai 200433China Research Center for Intelligent Computing Platforms Zhejiang LaboratoryHangzhou 311121China Wenzhou institute of Hangzhou Dianzi University Wenzhou 325038China Anhui Key Laboratory of Magnetic Functional Materials and Devices School of Materials Science and EngineeringAnhui UniversityHefei 230601China

Using micromagnetic simulations, we demonstrate the tilted perpendicular anisotropy-induced spin-orbit ratchet effect. In spin-orbit torque(SOT)-induced magnetization switching, the critical currents required to switch between the two magnetization states(upward and downward magnetization) are asymmetric. In addition, in the nanowire structure, tilted anisotropy induces formation of tilted domain walls(DWs). The tilted DWs exhibit a ratchet behavior during motion. The ratchet effect during switching and DW motions can be tuned by changing the current direction with respect to the tilting direction of anisotropy. The ratchet motion of the DWs can be used to mimic the leaky-integrate-fire function of a biological neuron, especially the asymmetric property of the “potential” and “reset” processes. Our results provide a full understanding of the influence of tilted perpendicular anisotropy on SOT-induced magnetization switching and DW motion, and are beneficial for designs of further SOT-based devices.

关键词： motion effect magnetization

Gravity anomaly during the Mohe total solar eclipse

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chinese Science Bulletin 2001年第21期46卷 1833-1836页

作者： wang qianshen YANG Xinshe TANG Keyun institute of geophysics Chinese Academy of SciencesBeijing 100101China Department of Applied Mathematics University of LeedsLeeds LS2 9JTUK

By using a high-precision LaCoste-Romberg (D-12.#) gravimeter, continuous and precise measurements were carried out during the March 9,1997 total solar eclipse in the Mohe region in Northeast China. The gravity variations were digitally recorded during the total solar eclipse so as to investigate the possible anomaly of the sun and the moon’s gravitational fields on the earth. After the careful processing and analysis of the observed data, no significant anomaly during the very solar eclipse has been found. However, there are two ’gravity anomaly valleys’ with near symmetrical decrease of about 6-7 μGal at the first contact and the last contact. This is the anomaly phenomenon observed and reported for the first time in the literature. This note presents some analyses and discussions.

关键词： Mohe total solar eclipse gravity anomaly.

Biomass-based production of trimellitic and trimesic acids

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Green Energy & Environment 2024年第8期9卷 1267-1278页

作者： Lin Yuan Yancheng Hu Guangyi Li Fengan Han Aiqin wang Yu Cong Tao Zhang Feng wang Ning Li CAS Key Laboratory of Science and Technology on Applied Catalysis Dalian Institute of Chemical PhysicsChinese Academy of Sciences University of chinese academy of sciences 19 A Yuquan RoadShijingshan District School of Chemical Engineering and Technology China University of Mining and Technology State Key Laboratory of Catalysis Dalian National Laboratory for Clean EnergyDalian Institute of Chemical PhysicsChinese Academy of Sciences

The production of industrial chemicals with renewable biomass feedstock holds potential to aid the world in pursuing a carbon-neutral *** and trimesic acids are important commodity chemicals in industry that are prepared by the oxidation of petroleum-derived *** reduce the dependence on the limited oil source,we develop a potential sustainable alternative towards trimellitic and trimesic acids using biomass-based 2.methyl-2.4-pentandiol （MPD）,acrylate and crotonaldehyde as starting *** process for trimellitic acid includes dehydration/D-A reaction of MPD and acrylate,flow aromatization over Pd/C catalyst,hydrolysis and catalytic aerobic oxidation （60%overall yield）.The challenging regioselectivity issue of D-A reaction is tackled by a matched combination of temperature and deep eutectic solvent ChCl/*** can also participate in the reaction,followed by Pd/C-catalyzed decarbonylation/dehydrogenation and oxidation to provide trimesic acid in 54%overall *** cycle assessment implies that compared to conventional fossil process,our biomass-based routes present a potential in reducing carbon emissions.

关键词： Biomass Trimellitic acid Trimesic acid Deep eutectic solvent Dehydration/D-A reaction

SYNTHESIS AND CHARACTERIZATION OF PHENOTHIAZINE-BASED PPV-TYPE COPOLYMERS CONTAINING FLUORENE AND THIOPHENE MOIETIES

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chinese Journal of Reactive Polymers 2005年第Z1期 28-34页

作者： wang Chen1 LU Yan1 LIU Song1 YANG Liying1 YIN Shougen1 Silvia Janietz2.Hartmut Krueger2.Armin Wedel2.HUA yulin1.1 {2. of Material Physics, Tianjin University of Technology, Tianjin 3.0191, China 2.Fraunhofer {2. of Applied Polymer Research, Geiselbergstrasse 69, D-14476 Golm, Germany

Copolymers of fluorene-co-phenothiazine (P1) and thiophene-co-phenothiazine (P2. were prepared respectively by Wittig reaction. The synthesis, photo-physical and electroluminescent properties of the resulting polymers were analyzed by FT-IR, GPC, 1H-NMR, UV-Vis, Photoluminescence (PL), Electroluminescence (EL) and Cyclic Voltammetry (CV). Their single layer devices with configuration of ITOpolymersCaAl were studied. GPC results revealed the weight-average molecular weight (Mw) was 3.0×103.and 5.4×103. respectively. The device with a single layer structure of ITOP1CaAl emits green light with the maximum peak at 552.m. However, the device with a single layer structure of ITOP2.aAl emit red light with the maximum peak at 616nm.

关键词： Phenothiazine Fluorene Thiophene Wittig-reaction Electroluminescence.

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新型抗生素筛选的研究进展

中国抗生素杂志 2024年第7期49卷 764-771页

作者：徐敏王丽卫辛念邓玉林刘凤北京理工亘舒科技有限公司北京100081 北京理工大学北京100081

抗生素耐药性是一个重要的公共卫生问题,由于细菌耐药性的不断进化和传播,尤其是“超级细菌”的出现,导致传染病发病率和死亡率不断增加,治疗也变得更具挑战性,因此,新型抗生素的研究至关重要。进入抗生素后时代以来,大批新技术、新方... 详细信息

抗生素耐药性是一个重要的公共卫生问题,由于细菌耐药性的不断进化和传播,尤其是“超级细菌”的出现,导致传染病发病率和死亡率不断增加,治疗也变得更具挑战性,因此,新型抗生素的研究至关重要。进入抗生素后时代以来,大批新技术、新方法为新型抗生素的筛选提供了思路。本文对新型抗生素筛选和替代方法的进展进行了总结,包括从天然产物中筛选、采用化学合成或合成生物学方法筛选、基于组学技术的筛选、人工智能辅助筛选、药物再利用和联合用药以及抗生素的替代疗法如单克隆抗体疗法、噬菌体疗法。新型抗生素的筛选对于应对多耐药菌、治疗新兴疾病、提高治疗效果都具有重要意义,药物再利用、联合用药及抗生素的替代疗法可以降低药物开发的时间和成本,为医疗领域带来更多的创新和进步。

关键词：新型抗生素耐药性抗菌疗法筛选人工智能

3.3.,4,4'-联苯四胺改性邻苯二甲腈树脂及其复合材料性能

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高分子材料科学与工程 2024年第2期40卷 65-73页

作者：董俊宇赵星诺章宇琳刘小僮王文蓓周权吴霄华东理工大学材料科学与工程学院特种功能高分子材料及相关技术教育部重点实验室上海200237 中国航空工业集团公司济南特种结构研究所山东济南250023

采用3.3.,4,4'-联苯四胺(LBS)与联苯型邻苯二甲腈树脂(BPh)进行预聚反应制备改性联苯型邻苯二甲腈树脂预聚物(BLBS)。利用红外光谱法、差示扫描量热仪、旋转流变仪和热重分析对BLBS的固化行为、流变性能和耐温性能进行研究。结果表明,B... 详细信息

采用3.3.,4,4'-联苯四胺(LBS)与联苯型邻苯二甲腈树脂(BPh)进行预聚反应制备改性联苯型邻苯二甲腈树脂预聚物(BLBS)。利用红外光谱法、差示扫描量热仪、旋转流变仪和热重分析对BLBS的固化行为、流变性能和耐温性能进行研究。结果表明,BLBS最低可在2.0℃前开始固化,但仍需要较高的温度才能固化完全;BLBS-3.化物在氮气和空气氛围中的质量损失5%时的温度(Td5)分别为549.4℃和555.6℃。石英纤维增强BLBS复合材料(QF/BLBS)具有优异的力学性能和耐热性能,玻璃化转变温度(T_(g))大于500°C,室温弯曲强度和层间剪切强度分别为711.5 MPa和48.5 MPa,400℃热处理2.h后弯曲强度和层间剪切强度分别为680.5 MPa和3..3.MPa。

关键词：联苯型邻苯二甲腈 3.3.,4,4'-联苯四胺耐热性能力学性能复合材料

Carrying Capacity and Coupling Coordination of Water and Land Resources Systems in Arid and Semi-arid Areas: A Case Study of yulin City, China

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chinese Geographical Science 2024年第5期34卷 931-950页

作者： ZHANG Qianxi CAO Zhi wang Yongsheng HUANG Yijia institute of Geographic sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

Quantitatively assessing the carrying capacity of water and land resources systems in arid and semi-arid areas is crucial for achieving the 2.3. Sustainable Development *** this work,taking yulin City in China as a case study and employing the Criteria Importance Through Intercriteria Correlation(CRITIC)method,a modified model of coupling degree was developed to evaluate the car-rying capacity of water and land resources systems endowment and utilization,as well as their coupling coordination degree from 2.13.to *** findings indicate that the water and land resources of yulin are diminishing due to declines in agriculture,higher industrial water use,and wetland ***,reallocating domestic water for ecological sustainability and reducing sloping farmland can mitigate this trend of ***,as the coupling coordination between water and land resources system endowment in yulin continuously improved,the coupling coordination between water and land resources system utilization first decreased and then in-creased with 2.16 as the turning ***,the carrying capacity of water and land resources systems,the coupling coordination degree between water and land resources system endowment,and the coupling coordination degree between water and land resources system utilization in yulin exhibited the same pattern of being higher in the six northern counties than in the six southern *** the water resources endowment is vital for the highly efficient use of water and land resources.

关键词： water and land resources systems carrying capacity coupling coordination human-earth system sustainable development yulin City,China