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基于暂态电流波形拟合的直流微电网故障定位方法

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供用电 2025年第1期42卷 13-23页

作者：于泽学张雨宁占柠郝治国王挺国网山东省电力公司德州供电公司山东德州253008 西安交通大学电气工程学院陕西西安710049

直流微电网是未来电力系统的重要发展方向。为了加快故障恢复速度、减少用户停电时间,直流微电网的故障定位技术至关重要。提出了基于暂态电流波形拟合的直流微电网线路故障单端定位方法。该方法基于直流微电网的高频等效模型,推导出与... 详细信息

直流微电网是未来电力系统的重要发展方向。为了加快故障恢复速度、减少用户停电时间,直流微电网的故障定位技术至关重要。提出了基于暂态电流波形拟合的直流微电网线路故障单端定位方法。该方法基于直流微电网的高频等效模型,推导出与故障距离和电阻有关的故障电流时域表达式,再通过对实测故障电流波形进行拟合,估计电流时域表达式中的未知参数,进而实现故障距离的精确估计。最后分别在基于MATLAB/Simulink的三端环状直流微电网仿真环境以及硬件测试环境下,对所提故障定位方法的可行性和有效性进行了充分验证,结果表明该方法具有较高的故障定位精度、速度和噪声鲁棒性。

关键词：直流微电网保护故障定位参数估计粒子群优化

Anomeric configuration-dependence of the Lattrell-Dax epimerization from D-glucose to synthetically useful D-allose derivatives

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Chinese Journal of Natural Medicines 2020年第10期18卷 723-728页

作者： ning Yun-zhan QIN Chun-Jun SUN Wen-Bin FU Jun-Jie HU Jing YIN Jian Key Laboratory of Carbohydrate Chemistry and Biotechnology Ministry of EducationSchool of BiotechnologyJiangnan UniversityWuxi 214122China Wuxi School of Medicine Jiangnan UniversityWuxi 214122China

D-Allose and its derivatives play important roles in the field of health care and food nutrition. Pure and well-defined Dallose derivatives can facilitate the elucidation of their structure-activity relationship as an essential step for drug design. The LattrellDax epimerization, refers to the triflate inversion using nitrite reagent, is known as valuable method for the synthesis of rare D-allose derivatives. Here, the influence of protecting group patterns on the transformation efficiency of D-glucose derivatives into synthetically useful D-alloses and D-allosamines via the Lattrell-Dax epimerization was studied. For C3 epimerization of D-glucose derivatives bearing O2-acyl group, an anomeric configuration-dependent acyl migration from O2 to O3 was found. In addition, a neighbouring group participation effect-mediated SN1 nucleophilic substitution of the D-glucosamine bearing C2 trichloroacetamido(TCA) group in the Lattrell-Dax epimerization was dependent upon anomeric configuration. Thus, the effect of anomeric configuration on the LattrellDax epimerization of D-glucose suggests that β-D-glucosides with low steric hindrance at C2 should be better substrates for the synthesis of D-allose derivatives. Significantly, the efficient synthesis of the orthogonally protected D-allose 13 and D-allosamine 18 will serve well for further assembly of complex glycans.

关键词： D-allose D-allosamine Epimerization Anomeric configuration Acyl migration

Measurement of in-vehicle volatile organic compounds under static conditions

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Journal of Environmental Sciences 2007年第10期19卷 1208-1213页

作者： YOU Ke-wei GE Yun-shan HU Bin ning zhan-wu ZHAO Shou-tang zhanG Yan-ni XIE Peng School of Mechanical and Vehicular Engineering Beijing Institute of Technology Beijing 100081 China Beijing Municipal Institute of Labor Protection Beijing 100054 China

The types and quantities of volatile organic compounds （VOCs） inside vehicles have been determined in one new vehicle and two old vehicles under static conditions using the Thermodesorber-Gas Chromatograph/Mass Spectrometer （TD-GC/MS）. Air sampling and analysis was conducted under the requirement of USEPA Method TO-17. A room-size, environment test chamber was utilized to provide stable and accurate control of the required environmental conditions （temperature, humidity, horizontal and vertical airflow velocity, and background VOCs concentration）. Static vehicle testing demonstrated that although the amount of total volatile organic compounds （TVOC） detected within each vehicle was relatively distinct （4940 μg/m^3 in the new vehicle A, 1240 μg/m^3 in used vehicle B, and 132 μg/m^3 in used vehicle C）, toluene, xylene, some aromatic compounds, and various C7-C12 alkanes were among the predominant VOC species in all three vehicles tested. In addition, tetramethyl succinonitrile, possibly derived from foam cushions was detected in vehicle B. The types and quantities of VOCs varied considerably according to various kinds of factors, such as, vehicle age, vehicle model, temperature, air exchange rate, and environment airflow velocity. For example, if the airflow velocity increases from 0.1 m/s to 0.7 m/s, the vehicle＇s air exchange rate increases from 0.15 h^-1 to 0.67 h^-1, and in-vehicle TVOC concentration decreases from 1780 to 1201 μg/m^3.

关键词： volatile organic compounds (VOCs) in-vehicle trim material static conditions

Accelerated partial breast irradiation:Current evidence and future developments

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Cancer Innovation 2024年第1期3卷 104-112页

作者： Dandan Song Honghong zhang Chengbo Ren ning zhan Liangxi Xie Wenjia Xie Department of Radiation Oncology Xiang'an Hospital of Xiamen UniversityCancer Research CenterSchool of MedicineXiamen UniversityXiang'anXiamenChina Department of Radiation Oncology The First Affiliated Hospital of Hebei North UniversityZhangjiakouHebeiChina

Whole breast irradiation after breast-conserving surgery for early breast cancer has become one of the standard treatment modes for breast cancer and yields the same effect as radical *** partial breast irradiation(APBI)as a substitute for whole breast irradiation for patients with early breast cancer is a hot spot in clinical *** is characterised by simple high-dose local irradiation of the tumour bed in a short time,thus improving convenience for patients and saving *** implementation methods of APBI mainly include brachytherapy,external beam radiation therapy,and intraoperative *** review provides an overview of the clinical effects and adverse reactions of the main technologies of APBI and discusses the prospects for the future development of APBI.

关键词： accelerated partial breast irradiation brachytherapy breast cancer breast conserving surgery external beam radiation therapy intraoperative radiotherapy

Postmastectomy radiotherapy in breast reconstruction:Current controversies and trends

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Cancer Innovation 2024年第1期3卷 113-123页

作者： Honghong zhang Dandan Song Liangxi Xie ning zhan Wenjia Xie Jianming zhang Department of Radiation Oncology Xiang'an Hospital of Xiamen UniversityCancer Research CenterSchool of MedicineXiamen UniversityXiang'anXiamenFujianChina Fujian Provincial Key Laboratory of Intelligent Identification and Control of Complex Dynamic System Quanzhou Institute of Equipment ManufacturingHaixi InstitutesChinese Academy of SciencesQuanzhouFujianChina

Breast cancer is the most common cancer among women *** radiotherapy(PMRT)is an essential component of combined therapy for early-stage,high-risk breast *** reconstruction(BR)is often considered for patients with breast cancer who have undergone *** has been a considerable amount of discussion about the optimal approach to combining PMRT with BR in the treatment of breast *** may increase the risk of complications and prevent good aesthetic results after BR,while BR may increase the complexity of PMRT and the radiation dose to surrounding normal *** purpose of this review is to give a broad overview and summary of the current controversies and trends in PMRT and BR in the context of the most recent literature available.

关键词： breast reconstruction postmastectomy radiotherapy radiotherapy techniques

Upgrade of nickel and iron from low-grade nickel laterite by improving direct reduction-magnetic separation process

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Journal of Iron and Steel Research International 2022年第8期29卷 1164-1175页

作者： Hong-yu Tian Zheng-qi Guo Ruo-ning zhan Jian Pan De-qing Zhu Cong-cong Yang Liao-ting Pan Xue-zhong Huang School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083HunanChina Beibu Gulf New Materials Co. Ltd.Beihai 536000GuangxiChina

Low-grade saprolite nickel laterite,characterized by complicated minerals composition and fine-grained and complex dissemination,was commonly treated with a low recovery efficiency of Ni and Fe by conventional ***,an improved direct reduction and magnetic separation process was ***,the mechanisms on the enhanced growth of the Ni-Fe particles and the phase transformation in the nickel laterite pellets were *** low-nickel concentrates as a nucleating agent can obviously decrease the activation energy for growth of Ni-Fe alloy particles during the improved direct reduction process from 197.10 to 154.81 kJ/mol when the low-nickel concentrates were added from 0 to 20%.Hence,it is able to decrease nucleation barrier,induce the growth of Fe-Ni alloy particles and increase their average *** a result,the size of Ni-Fe particles in the pellets from less than 10 lm grew to more than 20 lm,which is beneficial for the full liberation and recovery of Ni and Fe in subsequent magnetic separation ***,the preferable Ni-Fe alloy concentrates with 6.44%Ni and 82.48%Fe can be prepared with corresponding recovery rates of 96.90%and 95.92%,respectively,when adding 20%low-nickel concentrates.

关键词： Nickel laterite Low-nickel concentrate Nucleating agent Growth kinetics Ni-Fe alloy Direct reduction Magnetic separation

Integrable Multi-impurity Open XXZ Chain with Next-Nearest-Neighbor Interaction

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Chinese Physics Letters 1999年第6期16卷 434-436页

作者： LAI Yun-zhong zhanG Ai-zhen HU zhan-ning LIANG Jiu-qing PU Fu-ke Institute of Physics and Center for Condensed Matter Physics Chinese Academy of SciencesBeijing 100080 Institute of Theoretical Physics Shanxi UniversityTaiyuan 030006 Department of Applied Science Taiyuan Heavy Machinery InstituteTaiyuan 030024 Department of Physics Guangzhou Normal CollegeGuangzhou 510400

The Hamiltonian of one-dimensional integrable multi-impurity XXZ spin chain with open boundary cases is constructed by using the method of adding parameters to the vertical *** is the first approach to add multi-impurity and next-nearest-neighbor interaction to the integrable anisotropic Heisenberg spin *** is found that all of the impurity parameters in the bulk must be pure imaginary numbers if the cross parameter is real for getting the hermitian Hamiltonian,or vice versa,when the next-nearest-neighbor interactions are *** Hamiltonian can be also applied to describe the many body systems with two kinds of particles if all of the impurity parameters are equal.

关键词： integrable Hamiltonian neighbor

Enhanced ultrafine multimode fiber imaging based on mode modulation through singular value decomposition

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Photonics Research 2024年第10期12卷 2214-2225页

作者： ning zhan ZHENMING YU LIMING CHENG JINGYUE MA JIAYU DI YUEHENG LAN KUN XU State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and TelecommunicationsBeijing 100876China School of Science Beijing University of Posts and TelecommunicationsBeijing 100876China

The utilization of multimode fibers(MMFs)displays significant potential for advancing the miniaturization of optical ***,the imaging quality is constrained by the physical conditions of MMF,which is particularly serious in small-core MMFs because of the limited mode *** break this limitation and enhance the imaging ability of MMF to the maximum,we propose a mode modulation method based on the singular value decomposition(SVD)of MMF’s transmission matrix(TM).Before injection into the MMF,a light beam is modulated by the singular vectors obtained by *** the singular vectors couple the light field into eigenchannels during transmission and selectively excite the modes of different orders,the optimal distribution of the excited modes in MMF can be achieved,thereby improving the imaging quality of the MMF imaging system to the greatest *** conducted experiments on the MMF system with 40μm and 105μm cores to verify this *** learning is utilized for image *** experimental results demonstrate that the properties of the output speckle pattern were customized through the selective excitation of optical modes in the *** applying singular vectors for mode modulation,the imaging quality can be effectively improved across four different types of *** in the ultrafine 40μm core MMF,the peak signal-to-noise ratio can be increased by up to 7.32 dB,and the structural similarity can be increased by up to 0.103,indicating a qualitative performance improvement of MMF imaging in minimally invasive medicine.

关键词： singular value thereby

一种新的基于反馈的数字预失真器模型（英文）

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北京邮电大学学报 2017年第5期40卷 75-81页

作者：赵霞李瞻宁同济大学电子与信息工程学院上海201804

数字预失真器是线性化功率放大器的有效工具.记忆多项式等模型难以兼顾模型的精确性和复杂程度.为解决该问题,提出了一种基于反馈的多项式模型建模数字预失真器.不仅使用输入信息,还使用过去时刻的输出信息,用较少的系数个数对高非线性... 详细信息

数字预失真器是线性化功率放大器的有效工具.记忆多项式等模型难以兼顾模型的精确性和复杂程度.为解决该问题,提出了一种基于反馈的多项式模型建模数字预失真器.不仅使用输入信息,还使用过去时刻的输出信息,用较少的系数个数对高非线性及深记忆效应的功率放大器建立模型.仿真结果显示,该模型比一些常见的模型可更有效地缓解功率放大器的幅值和相位失真.

关键词：功率放大器记忆多项式数字预失真器信号处理