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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 202-212页

作者： Nana chang Guobing Song Zhongxue chang Yuping zheng Xingang Yang the School of Electrical Engineering Xi’an Jiaotong UniversityXi’anChina State Key Laboratory of Smart Grid Protection and Control NARI Group CorporationNanjingChina Electric Power Research Institute of State Grid Shanghai Electric Power Company ShanghaiChina

The setting work of backup protection using steady-state current is tedious,and mismatches occasionally occur due to the increased proportion of distributed generations(DGs)connected to the power ***,there is a practical need to study a backup protection technology that does not require step-by-step setting and can be adaptively *** paper proposes an action sequence adaptive to fault positions that uses only positive sequence fault component(PSFC)*** the influence of DGs,the unified time dial setting can be obtained by selecting specific *** protection performance is improved by using the adjacent upstream and downstream protections to meet the coordination time interval in the case of metallic faults at the near-and far-ends of the ***,the expression and implementation scheme for inverse-time backup protection(ITBP)based on the unified characteristic equation is *** results show that this scheme can adapt to DG penetration scenarios and can realize the adaptive coordination of multi-level relays.

关键词： Inverse-time backup protection(ITBP) distributed generation(DG) positive sequence fault component(PSFC)voltage unified characteristic equation adaptive coordination

ess Enhanced photothermoelectric conversion in selfrolled tellurium photodetector with geometryinduced energy localization

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Light(Science & Applications) 2024年第8期13卷 1545-1556页

作者： Jiayuan huang Chunyu You Binmin Wu Yunqi Wang Ziyu Zhang Xinyu Zhang chang Liu Ningge huang Zhi zheng Tingqi Wu Suwit Kiravittaya Yongfeng Mei Gaoshan huang Department of Materials Science&State Key Laboratory of Molecular Engineering of Polymers Fudan UniversityShanghai 200438China Yiwu Research Institute of Fudan University Yiwu 322000 ZhejiangChina International Institute of Intelligent Nanorobots and Nanosystems Fudan UniversityShanghai 200438China ShanghaiTech Quantum Device Lab ShanghaiTech UniversityShanghai 200120China Department of Electrical Engineering Faculty of EngineeringChulalongkorn UniversityBangkokThailand Shanghai Frontiers Science Research Base of Intelligent Optoelectronics and Perception Institute of OptoelectronicsFudan UniversityShanghai 200438China

Photodetection has attracted significant attention for information *** the implementation relies primarily on the photonic detectors,they are predominantly constrained by the intrinsic bandgap of active *** the other hand,photothermoelectric(PTE)detectors have garnered substantial research interest for their promising capabilities in broadband detection,owing to the self-driven photovoltages induced by the temperature *** get higher performances,it is crucial to localize light and heat energies for efficient ***,there is limited research on the energy conversion in PTE detectors at micro/nano *** this study,we have achieved a twoorder-of-magnitude enhancement in photovoltage responsivity in the self-rolled tubular tellurium(Te)photodetector with PTE *** illumination,the tubular device demonstrates a maximum photovoltage responsivity of 252.13 VW^(-1)and a large detectivity of 1.48×10^(11)*** disclose the mechanism of the PTE conversion in the tubular structure with the assistance of theoretical *** addition,the device exhibits excellent performances in wide-angle and polarization-dependent *** work presents an approach to remarkably improve the performance of photodetector by concentrating light and corresponding heat generated,and the proposed self-rolled devices thus hold remarkable promises for next-generation on-chip photodetection.

关键词： illumination energy primarily

An Online Compensation Method of DC Drift for Three-Phase Current Reconstruction with DC-Link Resistance

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Chinese Journal of Electronics 2020年第5期29卷 982-990页

作者： huang Lili zheng Lianqing LI Pengwei Department of Electric Machine and Electric Apparatus School of Electrical Engineering Chongqing University State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University

In a three-phase power convertor system,phase current reconstruction technique using a DC-link resistance can reduce the cost and weight of the diving system. The three-phase current without DC offset in normal condition is introduced in this paper *** on this premise, the DC-link current offset is considered and the logical relationship between threephase voltage, three-phase current, and DC offset are analyzed and depicted. The DC offset introduced during the sampling processes a distortion into phase current,which is composed of fundamental and harmonic frequency based on FFT analysis. The fundamental component of the distortion shares the same phase angle with counterpart voltage, which distorts power factor and amplitude of three-phase currents. The harmonic components of the distortion can be transformed into 6th harmonic components in synchronous dq axes and undermine the performance of the controlling system. After that, a practical method is proposed to solve this problem, namely sampling the DC offset signal during the period of the zero voltage vectors. An analogy sample circuit is designed and tested. This method can avoid the DC offset from the source. Finally, its effectiveness is verified via simulation and experiment.

关键词： Phase current reconstruction DC offset FFT analysis Current deviation

One-step conversion of methane and formaldehyde to ethanol over SA-FLP dual-active-site catalysts: A DFT study

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Chinese Chemical Letters 2024年第4期35卷 544-548页

作者： Tao Ban Xi-Yang Yu Hai-Kuo Tian zheng-Qing huang Chun-Ran chang Shaanxi Key Laboratory of Energy Chemical Process Intensification School of Chemical Engineering and TechnologyXi'an Jiaotong UniversityXi'an 710049China Shaanxi Key Laboratory of Low Metamorphic Coal Clean Utilization School of Chemistry and Chemical EngineeringYulin UniversityYulin 719000China

One-step conversion of methane and formaldehyde into ethanol is a 100% atom-efficient process for carbon resources utilization and environment protection but still faces eminent challenges due to the lacking of efficient catalysts. Therefore, developing active and stable catalysts is crucial for the co-conversion of methane and formaldehyde. Herein, twelve kinds of “Single-Atom”-“Frustrated Lewis Pair”(SA-FLP)dual-active-site catalysts are designed for the direct conversion of methane and formaldehyde to ethanol based on density functional theory(DFT) calculations and microkinetic simulations. The results show that the SA-FLP dual active sites can simultaneously activate methane at the SA site and activate formaldehyde at the FLP site. Among the twelve designed SA-FLP catalysts, Fe1-FLP shows the best performance in the co-conversion of methane and formaldehyde to ethanol with the rate-determining barrier of 1.15 e *** is proved as the main product with the turnover frequency of 1.32 × 10^(-4)s^(-1)at 573 K and 3 *** work provides a universal strategy to design dual active sites on metal oxide materials and offers new insights into the effective conversion of methane and formaldehyde to desired C_(2) chemicals.

关键词： Single-atom Frustrated Lewis pairs Methane conversion Dual active sites Ethanol synthesis

Recent Advances in Coordination-Insertion Copolymerization of Ethylene with Polar Functionalized Comonomers

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Chinese Journal of Chemistry 2020年第11期38卷 1445-1448页

作者： Guixia Liu zheng huang School of Chemistry and Material Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of Sciences1 Sub-lane XiangshanHangzhouZhejiang 310024China State Key Laboratory of Organometallic Chemistry Center for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of Sciences345 Lingling RoadShanghai 200032China chang-Kung Chuang Institute East China Normal UniversityShanghai 200062China

Increasing demand for polar functionalized polyolefins has motivated the development of new polymerization chemistry to introduce functional groups into polyolefins,which is industrially important but scientifically ***-insertion copolymerization of ethylene and polar comonomers offers a direct and economic way to synthesize functionalized polyethylenes and great achievements have been gained by employing catalytic systems based on transition metals and rare earth *** efforts have been devoted to developing novel catalytic systems and strategies to introduce chemically diverse functionalities at specific positions,control over the microstructures and get high molecular weight functionalized polyethylenes with high activity and good enchainment *** article summarizes some important advances in the past three years in this field,focusing on the studies using chemically diverse polar comonomers to afford functionalized polyethylenes with novel microstructures.

关键词： chemically Ethylene devoted

生物反馈助力电刺激对慢性非特异性腰痛患者下肢步行功能的改善

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中国组织工程研究 2025年第3期29卷 547-553页

作者：郑翔张明兴黄雅单莎瑞广东药科大学附属第一医院广东省广州市510080

背景:国内外关于慢性非特异性腰痛生物反馈疗法和三维步态功能分析的相关研究已开展很多,但是对二者结合的研究少有报道。目的:利用三维步态分析采集步态参数数据,研究生物反馈助力电刺激对慢性非特异性腰痛患者步行能力的改变效果。方... 详细信息

背景:国内外关于慢性非特异性腰痛生物反馈疗法和三维步态功能分析的相关研究已开展很多,但是对二者结合的研究少有报道。目的:利用三维步态分析采集步态参数数据,研究生物反馈助力电刺激对慢性非特异性腰痛患者步行能力的改变效果。方法:选择2021年6月至2022年9月在广东药科大学附属第一医院收治的60例慢性非特异性腰痛患者,男34例,女26例,年龄32-58岁。采用随机数字表法将60例患者分为对照组(n=30)与试验组(n=30),两组患者均接受腰部动态干扰电的常规治疗(20 min/次,1次/d,每周5次,持续治疗20次),对照组患者在常规治疗的基础上进行仰卧搭桥和俯卧搭桥的悬吊核心肌群训练(每周5次,持续治疗20次),试验组在对照组治疗的基础上进行生物反馈助力电刺激治疗(20 min/次,1次/d,每周5次,持续治疗20次)。比较分析两组患者治疗前后的腰痛评分、肌电信号平均值和步态参数。结果与结论:①两组患者治疗结束后的数字类比表评分、日本骨科协会(JOA)评分、Oswestry功能障碍指数均较治疗前明显改善(P<0.05),试验组治疗结束后的数字类比表评分、JOA评分、Oswestry功能障碍指数均优于对照组(P<0.05);②两组患者治疗结束后的腹直肌、臀大肌、竖脊肌表面肌电平均值均高于治疗前(P<0.05),试验组治疗结束后的腹直肌、臀大肌、竖脊肌表面肌电平均值均高于对照组(P<0.05);③两组患者治疗结束后的步宽、步速、步频、健患侧步长比值、健患侧支撑相比值、患健侧摆动相比值、健患侧髋关节及膝关节矢状面活动度和健患侧足偏角均优于治疗前(P<0.05),试验组治疗结束后的上述指标均优于对照组(P<0.05);④结果表明,生物反馈助力电刺激能明显缓解慢性非特异性腰痛,改善了患者下肢步行功能。

关键词：三维步态生物反馈助力电刺激慢性非特异性腰痛步行功能核心稳定训练

Symmetry groups and Gauss kernels of Schrdinger equations

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Chinese Physics B 2012年第2期21卷 66-75页

作者： Kang Jing Qu chang-zheng Department of Mathematics Northwest UniversityXi'an 710069China Department of Mathematics Ningbo UniversityNingbo 315211China

The relationship between symmetries and Gauss kernels for the SchrSdinger equation iut = uxx ＋ f（x）u is established. It is shown that if the Lie point symmetries of the equation are nontrivial, a classical integral transformations of the Gauss kernels can be obtained. Then the Gauss kernels of Schroedinger equations are derived by inverting the integral transformations. Furthermore, the relationship between Gauss kernels for two equations related by an equivalence transformation is identified.

关键词： Schroedinger equation symmetry group Gauss kernel equivalence transformation

Fracture Analysis of Cast Iron Materials with Cracks Based on Elastoplastic Extended Finite Element Method

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Acta Mechanica Solida Sinica 2019年第2期32卷 201-214页

作者： Yanjun chang Qiao Song zheng Kuang Keshi Zhang Zhanguang zheng College of Civil Engineering and Architecture Guangxi University Nanning 530004 China College of Mechanical Engineering Guangxi University Nanning 530004 China Guangxi Key Laboratory of Disaster Prevention and Engineering Safety Guangxi University Nanning 530004 China Key Laboratory of Engineering Disaster Prevention and Structural Safety of Ministry of Education Guangxi University Nanning 530004 China

Based on the ABAQUS platform for finite element analysis, the extended finite element method (XFEM) considering elastoplastic constitutive relationship is developed, by which the displacement discontinuity across the crack surface and the strong nonlinearity near the crack tip can be described more accurately. The strip specimens with unilateral cracks and central cracks under uniaxial tension are simulated using the XFEM and the FEM, respectively. The J-integral across the crack on each incremen t is calcula ted using the equivale nt domain integral met hod (EDIM), the interaction integral met hod and the FEM, respectively. The effec ts of mesh size and mesh shape near the crack tip, element type and different calculation methods on the accuracy of J-integral are analyzed. The simulation results show that the XFEM is more accurate than the FEM with the same element size and type. The fracture tests of cast iron specimens with unilateral cracks under uniaxial tension are performed, and the J-integral criterion is valid to predict the fracture initiation in numerical simulation. The critical value of J-integral is calculated using the EDIM of the XFEM. The comparisons demonstrate that the simulated elastoplastic load-displacement curves with the XFEM are in good agreement with the experimental results.

关键词： J-Integral Extended finite element Elastoplasticity Fracture criterion

A hybrid proportional navigation based two-stage impact time control guidance law

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Journal of Systems Engineering and Electronics 2022年第2期33卷 461-473页

作者： huang Jia chang Sijiang CHEN Shengfu School of Energy and Power Engineering Nanjing University of Science and TechnologyNanjing 210094China The 20th Research Institute of China Electronics Technology Group Corporation Xi’an 710068China

To improve applicability and adaptability of the impact time control guidance(ITCG) in practical engineering, a twostage ITCG law with simple but effective structure is proposed based on the hybrid proportional navigation, namely, the pureproportional-navigation and the *** the case with the impact time error less than zero, the first stage of the guided trajectory is driven by the retro-proportionalnavigation and the second one is driven by the pure-proportionalnavigation. When the impact time error is greater than zero, both of the stages are generated by the pure-proportional-navigation but using different navigation gains. It is demonstrated by twoand three-dimensional numerical simulations that the proposed guidance law at least has comparable results to existing proportional-navigation-based ITCG laws and is shown to be advantageous in certain circumstances in that the proposed guidance law alleviates its dependence on the time-to-go estimation, consumes less control energy, and adapts itself to more boundary conditions and constraints. The results of this research are expected to be supplementary to the current research literature.

关键词： missile guidance law impact time control pure-proportional-navigation retro-proportional-navigation time-to-go estimation

Functional Separable Solutions of Nonlinear Heat Equations in Non-Newtonian Fluids

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Communications in Theoretical Physics 2008年第2期49卷 257-262页

作者： GOU Ming QU chang-zheng Center for Nonlinear Studies Northwest University Xi＇an 710069 China Department of Mathematics Northwest University Xi＇an 710069 China

We study the functional separation of variables to the nonlinear heat equation： ut = （A（x）D（u）ux^n）x＋ B（x）Q（u）, Ax≠0. Such equation arises from non-Newtonian fluids. Its functional separation of variables is studied by using the group foliation method. A classification of the equation which admits the functional separable solutions is performed. As a consequence, some solutions to the resulting equations are obtained.

关键词： group foliation method functional separation of variable nonlinear heat equation symmetry group