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Single-end Protection Scheme Based on Transient Power Waveshape for Hybrid HVDC Transmission Lines

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Journal of Modern Power Systems and Clean Energy 2023年第5期11卷 1673-1686页

作者： Feiyang Dai zexin Zhou Xingguo Wang China Electric Power Research Institute Co. Ltd.BeijingChina State Key Laboratory for Power Grid Safety and Energy Conservation BeijingChina

The recent in-depth development of hybrid highvoltage direct current(HVDC) transmission systems poses looming adaptability challenges to protection. The various and disparate direct current(DC) transmission topologies can profoundly affect the operating characteristics of DC transmission networks, which result in the lack of performance of conventional DC protection schemes in such topologies. This significantly limits the application of hybrid HVDC technologies. This paper proposes a single-end protection scheme based on the transient power waveshape for fast and sensitive detection and classification of different types of DC faults in hybrid HVDC transmission lines. The fault characteristics and their causes under different fault conditions are analyzed in detail with a pre-introduced linearized transient model of a hybrid HVDC transmission system, demonstrating that the formation of the fluctuation characteristics of local measurements is mainly determined by the buffering and absorption effects of lumped-parameter reactors on transient traveling-wave(TW) energy. Simulation results verify the sensitivity, rapidity, reliability, and anti-interference ability of the proposed scheme when applied to hybrid HVDC transmission lines. furthermore, it is confirmed that the proposed scheme is adaptable to symmetric voltage-sourced converter(VSC) and conventional line-commutated converter(LCC) based HVDC transmission lines.

关键词： High-voltage direct current(HVDC)transmission system line protection traveling-wave(TW) line-commutated convrter floating threshold

基于社交软件的浙江省大学生男男性行为者艾滋病检测情况及影响因素研究

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浙江医学教育 2019年第6期18卷 13-15,24页

作者：孙金铭傅泽鑫鲍凡凡陈晨宇李子豪杨云皓杭州医学院

为了解使用同性社交软件的大学生男男性行为人群(MSM)最近1年的HIV检测情况及其影响因素,本研究采用横断面调查,以我国最流行的同性社交软件为工具,调查浙江省大学生MSM。结果显示最近1年,浙江省大学生MSM既往检测率为48.61%(386/794),... 详细信息

为了解使用同性社交软件的大学生男男性行为人群(MSM)最近1年的HIV检测情况及其影响因素,本研究采用横断面调查,以我国最流行的同性社交软件为工具,调查浙江省大学生MSM。结果显示最近1年,浙江省大学生MSM既往检测率为48.61%(386/794),检测途径从多到少依次为:主动购买试纸检测42.23%(163/386)、主动前往医院/疾控中心检测30.31%(117/386)、献血点检测18.13%(70/386)、手术前检测6.22%(24/386)、在街头进行快速检测3.11%(3/386)。多因素分析结果显示,户口所在地、学制学历类型、是否接受过艾滋病自愿咨询检测(VCT)的相关知识的培训、是否对VCT的收费有正确认识、是否怀疑自身感染了HIV、近一年肛交固定性伴数是大学生MSM的HIV检测的影响因素。研究发现,他们更希望通过匿名、免费的方式获得HIV检测;要加强VCT的政策宣传和对HIV检测知识的宣传,帮助该人群掌握有效的预防及应对HIV感染的知识和技能。

关键词：男男性行为者大学生艾滋病检测

Effects of electric parameters on microstructure and properties of MAO coating fabricated on ZK60 Mg alloy in dual electrolyte

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Rare Metals 2012年第2期31卷 172-177页

作者： Chen, Jing Wang, zexin Lu, Sheng School of Materials Science and Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China School of Mechanical Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China

Micro-arc oxidation (MAO) process was carried out in a dual electrolyte system of NaAlO 2 and Na 3 PO 4 on ZK60 Mg alloys to explore the effect of electric parameters including current density, frequency, duty cycle and oxidation time on the evolution of coatings and other characteristics. The microstructural characteristics of coatings were observed by scanning electron microscopy (SEM) combined with the analysis of voltage-time responses during MAO process. Test of weight loss was conducted at a 3.5% NaCl solution to assess the resistance to corrosion. The results indicate that the current density and duty cycle play key roles on the coating quality. The peak voltage during MAO process increased with the increase in current density but the coating would be more easily detached when the current density was beyond a critical value. Voltage during MAO and microstructure of the coating were affected remarkably by duty cycle, and corrosion resistance was improved greatly when duty cycle was 40%. By means of single variable experiments, MAO process with optimized electric parameters was developed, which corresponds to the current density of 20 A dm 2 , frequency of 500 Hz, duty cycle of 40% and oxidation time of 15 min.

关键词： magnesium alloys micro-arc oxidation electrical parameters microstructure performance

Oriented electron tunneling transport in hierarchical Ag/SiO_(2)/TiO_(2) nanobowl arrays for plasmonic solar water splitting

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Nano Research 2022年第2期15卷 1593-1602页

作者： zexin Yu Lixia Sang Angran Cao Yunlong Gao MOE Key Laboratory of Enhanced Heat Transfer and Energy Conservation Beijing Key Laboratory of Heat Transfer and Energy ConversionBeijing MunicipalityBeijing University of TechnologyBeijing 100124China

Hierarchical Ag/SiO_(2)/TiO_(2) nanobowl(NB)arrays were fabricated for use as plasmonic photoanodes for solar-hydrogen *** nanobowls had large pore size and were composed of an upper TiO_(2) nanoring and a lower TiO_(2) nanohole.A thin SiO_(2) inter-layer was introduced as an electron transmission channel to change the mechanism of hot electron *** were performed to characterize the variation of electron concentration in Ag/SiO_(2)/TiO_(2) NB arrays,taking into account both the optical transition of photogenerated electrons,and electron *** multiphysics coupling function of COMSOL software provided the light source for optical transition of photogenerated electrons,and a Wentzel-Kramers-Brillouin model was employed to represent the *** results demonstrate that the TiO_(2) nanoring was a transporter,which transmitted electrons downward to the *** SiO_(2) layer replaces the Schottky barrier to become a bridge for tunneling of hot electrons in high-and low-energy states into TiO_(2).Moreover,the coverage of the SiO_(2) layer helped increase the light absorption of TiO_(2),it also reduced the near electric field coupling between Ag and TiO_(2).Accordingly,under AM 1.5 light irradiation,the photocurrent density and average hydrogen evolution rate of Ag/SiO_(2)/TiO_(2) were 1.8 and 2.2 times higher,respectively,than those of pure TiO_(2),implying far more efficient migration of carriers.

关键词： nanobowl tunneling Wentzel-Kramers-Brillouin(WKB)approximation hot electron SiO_(2)layer

Ion Migration and Accumulation in Halide Perovskite Solar Cells

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Chinese Journal of Chemistry 2023年第7期41卷 861-876页

作者： Lijian Zuo zexin Li Hongzheng Chen State Key Laboratory of Silicon Materials MOE Key Laboratory of Macromolecular Synthesis and FunctionalizationDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhouZhejiang310027 China Zhejiang University-Hangzhou Global Scientific and Technological Innovation Center HangzhouZhejiang310014 China

Comprehensive Summary The halide perovskite semiconductors-based solar cells(PVSCs)show great promise as next-generation renewable energy sources,with the merits of low cost,high performance,good flexibility,etc.A major difference distinguishing the perovskite semiconductors from others lies in their ionic *** intrinsic property induces“freely-moving”ions to migrate and accumulate in the perovskite films and devices under different external *** a charge carrier,these processes will strongly couple with the electronic process,and dramatically affect the performance and stability of *** review summarizes and discusses the recent progresses and fundamental understandings of ion migration and accumulation behaviors in ***,the basic principles of the general ion migration are ***,following the fundamental understandings,the critical factors,e.g.,ion migration activation energy,ion density,ion diffusion coefficient,etc.,are extracted to understand the ion migration and accumulation in perovskite ***,the principles governing ion accumulation behaviors under different external stresses are ***,the effect of ion migration and accumulation on band bending,and device performance is ***,we hope this review provides a tutorial and insightful perspective regarding the most prominent ionic feature of perovskite semiconductors and their application for photovoltaics.

关键词： Semiconductors Perovskite phases Crystal engineering Defects Photovoltaic

NeurstrucEnergy:A bi-directional GNN model for energy prediction of neural networks in IoT

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Digital Communications and Networks 2024年第2期10卷 439-449页

作者： Chaopeng Guo Zhaojin Zhong zexin Zhang Jie Song Software Campus Northeastern UniversityShenyang110000LiaoningChina

A significant demand rises for energy-efficient deep neural networks to support power-limited embedding devices with successful deep learning applications in IoT and edge computing *** accurate energy prediction approach is critical to provide measurement and lead optimization ***,the current energy prediction approaches lack accuracy and generalization ability due to the lack of research on the neural network structure and the excessive reliance on customized training *** paper presents a novel energy prediction model,*** treats neural networks as directed graphs and applies a bi-directional graph neural network training on a randomly generated dataset to extract structural features for energy *** has advantages over linear approaches because the bi-directional graph neural network collects structural features from each layer's parents and *** results show that NeurstrucEnergy establishes state-of-the-art results with mean absolute percentage error of 2.60%.We also evaluate NeurstrucEnergy in a randomly generated dataset,achieving the mean absolute percentage error of 4.83%over 10 typical convolutional neural networks in recent years and 7 efficient convolutional neural networks created by neural architecture *** code is available at https://***/NEUSoftGreenAI/***.

关键词： Internet of things Neural network energy prediction Graph neural networks Graph structure embedding Multi-head attention

1例难治性肾病综合征合并中毒性表皮坏死松解症患儿的护理

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当代护士(上旬刊) 2025年第1期32卷 136-139页

作者：曾悦惠黄泽鑫汕头大学医学院第二附属医院儿科汕头515041

总结1例难治性肾病综合征合并中毒性表皮坏死松解症患儿的护理体会。患儿既往确诊难治性肾病综合征,疾病导致大量蛋白丢失,加上长期应用激素治疗,导致此次发病全身多系统受累及,皮肤失去屏障功能,极易因严重感染导致败血症、感染性休克... 详细信息

总结1例难治性肾病综合征合并中毒性表皮坏死松解症患儿的护理体会。患儿既往确诊难治性肾病综合征,疾病导致大量蛋白丢失,加上长期应用激素治疗,导致此次发病全身多系统受累及,皮肤失去屏障功能,极易因严重感染导致败血症、感染性休克、多器官功能衰竭等并发症的发生,治疗及护理难度极大。本案例的护理要点包括严密观察病情变化、保护性护理措施、皮肤护理、管道周围皮肤的保护、口腔护理、眼部护理、会阴部护理、疼痛护理及心理护理。经过21 d的精细化护理,患儿全身皮肤、黏膜完整,剥脱皮损基本修复,病情好转出院。

关键词：护理难治性肾病综合征中毒性表皮坏死松解症

Genome sequencing provides insights into Caprifoliaceae genome evolution and the mechanism underlying second blooming phenomenon in Heptacodium miconioides

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Horticultural Plant Journal 2024年第3期10卷 897-910页

作者： Yueling Li Zhongshuai Sun zexin Jin Junmin Li Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation Taizhou UniversityTaizhouZhejiang 318000China Institute of Ecology Taizhou UniversityTaizhouZhejiang 318000China School of Life Sciences Taizhou UniversityTaizhouZhejiang 318000China

Plants of the Caprifoliaceae family are widely cultivated worldwide as ornamental plants owing to their numerous,sweet-smelling,beautiful flowers and *** miconioides Rehd.,a member of the family,is endemic to eastern China and is cultivated as a popular ornamental plant in North America and European *** has a rather novel and beautiful trait of high horticultural value,that is,its sepals persist and enlarge,turning purplish ***,we report the chromosome-level genome assembly of *** to understand its evolution and floral *** 622.28 Mb assembled genome harbored a shared whole-genome duplication with a related species,Lonicera *** genomic analysis suggested that chromosome fission events following genome duplication underlie the unusual chromosome number of these two species,as well as chromosome fission of another five chromosomes in ***,giving rise to a haploid chromosome number of 14(versus 9 in ***).In addition,based on transcriptome and chloroplast genome analysis of 17 representative species in the Caprifoliaceae,we assumed that large structural variations in the chromosomes of *** were not caused by *** in the candidate genes of the MADS-box family were detected in the *** genome,including AP1-,AP3-,and SEPexpanded,which might underlie the sepal elongation and development in this *** current findings provided a critical resource for genome evolution studies in Caprifoliaceae and it was an example of how multi-omics data can elucidate the regulation of important ornamental traits.

关键词： Heptacodium miconioides Genome assembly Caprifoliaceae Chromosome fusion Sepal traits

Preparation of Palygorskite-based Phase Change Composites for Thermal Energy Storage and Their Applications in Trombe Walls

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Journal of Wuhan University of Technology(Materials Science) 2017年第6期32卷 1306-1317页

作者：施韬 LI Shanshan 张豪 LI zexin ZHU Min College of Civil Engineering and Architecture Zhejiang University of Technology Hangzhou 310014 China Key Laboratory ofCivil Engineering Structures & Disaster Prevention and Mitigation Technology of Zhejiang Province College of Civil Engineering and Architecture Zhejiang University of Technology Hangzhou 310014 China

Palygorskite/paraffin phase-change composites were prepared by the combination of purified palygorskite clay and sliced paraffin. Then, this composite was used in the Trombe wall to improve its energy storage ability. further, its energy storage ability was compared to that of ordinary concrete wall through contrastive test. The experiments show that palygorskite clay is a type of clay mineral with strong adsorption ability, and the purity of natural palygorskite clay can reach up to 97.1% after certain purification processes. Paraffin is well adsorbed by palygorskite, and the test results show that the optimal adsorption ratio is palygorskite： paraffin = 2：1（mass ratio）. Palygorskite/paraffin phase change composites can be obtained by using palygorskite as the adsorbing medium to adsorb paraffin. The composite materials exhibit good heat storage（release） performance, which can store heat with increasing environment temperature and release heat with decreasing temperature. This property not only increases the inertia to environment temperature change, but also promotes the energy migration in different time and space, thus achieving a certain energy-saving effect. The application of palygorskite/paraffin phase change composite materials to the Trombe wall can significantly reduce the fluctuation of indoor temperature and enhance the thermal inertia of indoor environment. From the aspect of energy storage effect, the Trombe wall fabricated using PCMs is significantly superior to the concrete wall with the same thickness.

关键词： phase change materials palygorskite attapulgite trombe wall thermal energy storage paraffin