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Modeling of High-frequency Electromagnetic Oscillation for DC Fault in MMC-HVDC Systems

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CSEE Journal of Power and Energy Systems 2023年第3期9卷 1151-1160页

作者： Hong Shen Zhonghao Dongye Lei Qi Muxue Wang Xiangyu Zhang Peng qiu xiaoguang Wei State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China Electric Power Research Institute State Grid Zhejiang Electric Power CompanyHangzhou 310014China State Key Laboratory of Advanced Power Transmission Technology Global Energy Interconnection Research Institute Co.Ltd.Beijing 102209China

DC short-circuit faults pose a hazard to the operation of a modular multilevel converter(MMC)-based high voltage direct current(HVDC)system,necessitating reliable fault clearing solutions with rapid reaction.However,because the parasitic capacitances of the main equipment oscillate with the lumped inductances of the HVDC system,strong electromagnetic oscillations with multiple frequencies occur during clearance transients.These oscillations will disturb the HVDC system’s protection and control systems.Therefore,this paper focuses on the modeling of these oscillations.First,an equivalent circuit for the MMC-based HVDC system is proposed,taking into account the parasitic capacitances of the system’s major components,such as DC reactors,connecting cables,and DC circuit breakers(DCCBs).Second,four distinct oscillation stages are postulated based on action coordination of MMCs and DCCBs,and the associated analytical equations for the oscillation frequencies are derived.Third,a 200 kV MMC-based DC converter station is subjected to an 6ms/6kA pole-to-pole(PTP)short-circuit test.Electromagnetic oscillations have a frequency range of several kHz to several hundreds of kHz.The measured waveforms correspond well with simulated results,including the parasitic characteristics.Additionally,the relative errors between the simulated and measured frequencies are less than 5%.

关键词： DC short-circuit fault electromagnetic oscillation MMC-HVDC parasitic parameter wide-band model

Uncertainty relations for triples of observables and the experimental demonstrations

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Science China(Physics,Mechanics & Astronomy) 2023年第5期66卷 97-105页

作者： Huang-qiu-Chen Wang Bo Liu Yong-Nan Sun Qi-Ping Su Zhe Sun xiaoguang Wang School of Physics Hangzhou Normal UniversityHangzhou 310036China School of Information and Electrical Engineering Hangzhou City UniversityHangzhou 310015China Key Laboratory of Optical Field Manipulation of Zhejiang Province Department of PhysicsZhejiang Sci-Tech UniversityHangzhou 310018China

Uncertainty relations are of profound significance in quantum mechanics and quantum information theory.The well-known Heisenberg-Robertson uncertainty relation presents the constraints on the spread of measurement outcomes caused by the non-commutability of a pair of observables.In this article,we study the uncertainty relation of triple observables to explore the relationship between the standard deviations and the commutators of the observables.We derive and tighten the multiplicative form and weighted summation form uncertainty relations,which are found to be dependent not only on the commutation relations of each pair of the observables but also on a newly defined commutator in terms of all the three observables.We experimentally test the uncertainty relations in a linear optical setup.The experimental and numerical results agree well and show that the uncer-tainty relations derived by us successfully present tight lower bounds in the cases of high-dimensional observables and the cases of mixed states.Our method of deriving the uncertainty relation can be extended to more than three observables.

关键词： Heisenberg-Robertson uncertainty relation three observables commutation relation linear optical setup

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中枢神经细胞瘤术后放疗的价值研究

中华放射肿瘤学杂志 2024年第4期33卷 314-318页

作者：徐建堃陈怡东王雷明高莹赵永瑞冯瑾邱晓光首都医科大学宣武医院放射治疗科北京100053 首都医科大学宣武医院病理科北京100053 首都医科大学附属北京天坛医院放射治疗科北京100070

目的探讨中枢神经细胞瘤(CN)手术切除后接受辅助放疗的临床疗效。方法回顾性分析2001年1月至2020年12月在北京天坛医院和宣武医院收治的136例CN病例。患者初始治疗包括开颅肿瘤切除术(完全切除、近全切除、部分切除,后两者属于未完全切... 详细信息

目的探讨中枢神经细胞瘤(CN)手术切除后接受辅助放疗的临床疗效。方法回顾性分析2001年1月至2020年12月在北京天坛医院和宣武医院收治的136例CN病例。患者初始治疗包括开颅肿瘤切除术(完全切除、近全切除、部分切除,后两者属于未完全切除)和术后放疗。放疗采用三维适形或调强放疗,中位放疗剂量为54 Gy。复发后治疗包括挽救性手术和挽救性放疗。用Kaplan-Meier法计算总生存(OS)、无进展生存(PFS),用log-rank检验进行单因素分析,以评价各个预后因素对OS及PFS的影响,Cox回归模型分析多个预后因素对PFS和OS的影响。结果患者中位年龄28岁(6~66岁),中位随访时间为94.5(12~237)个月。全组中有79例接受了完全切除,其中术后有68例接受了辅助放疗;38例近全切除,术后有37例接受辅助放疗;16例接受部分切除,术后均行辅助放疗;3例接受了活检,术后均行放疗。全组共3例死亡,2例死于肿瘤复发,1例死于术后并发症。8例出现复发,其中原位复发7例,脊髓播散1例。全组5、10年OS率分别为98.5%和96.8%,5、10年PFS率分别为95.3%和91.6%。完全切除且未放疗组5、10年PFS率分别为90.9%、90.9%,完全切除+放疗组为96.6%、96.6%(P=0.338)。完全切除且未放疗组5、10年OS率分别为100%、100%,完全切除+放疗组为98.5%、98.5%(P=0.693)。完全切除±放疗组与未完全切除+放疗组的10年PFS率为95.8%∶90.3%(P=0.368),10年OS率为98.6%∶94.7%(P=0.436)。多因素分析显示,肿瘤位置、手术切除程度、是否辅助放疗和年龄对PFS和OS均无显著影响。共有81例出现晚期神经不良反应,其中1级69例、2级9例、3级3例;64.2%(52/81例)的患者出现短期记忆损害。结论CN接受单纯完全切除可获得很好的疗效,无需再行术后放疗。接受未完全切除的病例行术后辅助放疗可获得与完全切除相当的临床疗效。

关键词：神经细胞瘤完全切除未完全切除放射疗法,术后

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大型民机复合材料翼梁R区褶皱力学性能研究

高科技纤维与应用 2024年第3期49卷 24-26页

作者：樊维超仇翯辰方亚宁穆晓光中国商飞上海飞机制造有限公司复合材料中心上海200123 中国商飞北京民用飞机技术研究中心民用飞机结构与复合材料北京市重点实验室北京102211

翼梁是飞机主盒段结构的重要组成部件,在国际主流的大型民机中,翼梁采用T800级碳纤维复合材料制造;R区结构是翼梁的重要结构特征,其力学性能通常直接决定着翼梁产品的优劣。本文针对复合材料翼梁制造过程中存在的R区褶皱缺陷,制定R区褶... 详细信息

翼梁是飞机主盒段结构的重要组成部件,在国际主流的大型民机中,翼梁采用T800级碳纤维复合材料制造;R区结构是翼梁的重要结构特征,其力学性能通常直接决定着翼梁产品的优劣。本文针对复合材料翼梁制造过程中存在的R区褶皱缺陷,制定R区褶皱缺陷定量化标定方法,通过曲梁四点弯试验测试方法,对含R区缺陷和不含R区缺陷的试验件进行测试,研究其R区力学性能差异,为翼梁R区结构设计和产品接收标准的制定提供数据支持。

关键词：复合材料翼梁 R区褶皱

Analysis and suppression of voltage oscillation at DC circuit breaker terminal in DC fault transient process

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High Voltage 2022年第6期7卷 1194-1203页

作者： Hong Shen Xianrui Huang Lei Qi Xiangyu Zhang Xiaojun Ni Peng qiu xiaoguang Wei Xiang Cui State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijingChina Electric Power Research Institute State Grid Zhejiang Electric Power CompanyHangzhouChina State Key Laboratory of Advanced Power Transmission Technology State Grid Smart Grid Research Institute Co.Ltd.BeijingChina

High-frequency voltage oscillation occurs at the initial stage of DC short-circuit fault in the modular multilevel converter(MMC)-based high-voltage direct-current systems,which directly threatens the reliable operation of the secondary equipment in DC circuit breakers(DCCBs).Therefore,this paper focusses on the voltage oscillation characteristic at DCCB terminals,considered the stray parameters of connecting lines,the parasitic parameters of main equipment and the impedance of grounding grid,established equivalent circuit models of MMC-HVDC converter station at the initial stage of pole-topole and pole-to-ground fault,and obtained the analytical formula for the voltage oscillation frequency.Then,the comparison with the DC short-circuit test data of�200 kV MMC-HVDC converter station verified the validity of the models and revealed the mechanism of voltage oscillation.Finally,the influence of the parameters of the converter station on the oscillation characteristics was discussed.It was proposed to install the DCCB at the MMC valve's terminal near the DC side,and the oscillation frequency is about 10–60 kHz,which is more than 5 times lower than that at the DC reactor's terminal near the DC pole bus,and the disturbance of oscillation to DCCB was alleviated.

关键词： oscillation. oscillation transient

Effect of light and nutrients on interspecific interactions between submerged macrophytes:implications for restoration of multispecies aquatic vegetation in eutrophic lakes

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Journal of Oceanology and Limnology 2023年第5期41卷 1821-1833页

作者： Yiping WANG xiaoguang XU Dujun LI Yongjun LU Xinhou ZHANG Chuyao YANG qiu JIN Guoxiang WANG School of Water Resources and Hydropower Engineering Wuhan UniversityWuhan 430072China State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing Hydraulic Research InstituteNanjing 210029China School of Environment Nanjing Normal UniversityNanjing 210023China

Constructing multispecies submerged vegetation systems and maintaining stable seasonal succession is crucial for restoring shallow eutrophic lakes.However,little is known about the interactions between successional and existing species of different growth forms,particularly under the low light and high nutrient conditions of eutrophic lakes.We measured the functional traits of mature Vallisneria natans(Lour.)Hara plants and Potamogeton crispus L.shoots in monoculture and mosaic patterns under different light and nutrient conditions.The effect of light on functional traits of the submerged macrophyte species was more significant than that of nutrients,but the reverse was true for P.crispus biomass allocation.Moreover,interspecific interactions affected only the submerged macrophytes under the low light condition and varied with species.Specifically,the interaction of P.crispus to V.natans was biased towards competition,while the interaction of V.natans to P.crispus was converted from facilitation to competition by eutrophication,particularly in the homogenous mosaic growth pattern.This study demonstrates that sufficient light is a prerequisite and patch planting is an effective means to form a multispecies submerged vegetation system.In addition,we emphasize that the coexistence of eutrophication and low light will likely result in a competition between submerged macrophytes thus simplifying the vegetation,even if their growth forms and growing seasons are different.These findings help explain the collapse of multispecies submerged vegetation and guide the restoration of aquatic plants in eutrophic lakes.

关键词： submerged macrophyte light nutrient monoculture mosaic interspecific interaction

MUTYH is a potential prognostic biomarker and correlates with immune infiltrates in hepatocellular carcinoma

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Liver Research 2022年第4期6卷 258-268页

作者： Fan Yang Qinghai Lian Beibei Ni Xiusheng qiu Yizhan He xiaoguang Zou Fangping He Wenjie Chen Biotherapy Center The Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhouGuangdongChina Department of Infectious Diseases The First People's Hospital of KashiKashiXinjiangChina Xinjiang Medical University UrumqiXinjiangChina Cell-gene Therapy Translational Medicine Research Center The Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhouGuangdongChina Department of Hepatobiliary and Pancreatic Surgery The Eighth Affiliated Hospital of Sun Yat-sen UniversityShenzhenGuangdongChina

Background:Hepatocellular carcinoma(HCC)is a leading cause of cancer-related death worldwide.The development of biomarkers for early detection and monitoring of HCC has not shown significant prog-ress.Meanwhile,the second adenomatous polyposis-related gene,MUTYH,which encodes a DNA gly-cosylase,has been observed in its contribution to oxidative DNA damage repair.Abnormal expression of MUTYH can reduce cell survival rate.Therefore,this study investigated the usefulness of MUTYH in diagnosing and prognosis HCC.Materials and methods:Using The Cancer Genome Atlas(TCGA)data,we analyzed the prognostic value of MUTYH in HCC.We used logistic regression,Wilcoxon signed-rank test,and KruskaleWallis test to examine MUTYH expression concerning clinical-pathologic characteristics.Univariate and multivariate Cox regression methods and Kaplan-Meier analysis were applied to determine the related prognostic factors of HCC.The enrichment analysis(GSEA)was used to determine the critical pathways associated with MUTYH.The single-sample gene set enrichment analysis(ssGSEA)was conducted to examine the correlation between MUTYH expression and cancer immune infiltration.Results:The higher expression of MUTYH in HCC patients was associated with a poorer overall survival rate and a shorter disease-specific survival rate.The Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis showed that all differentially expressed genes(DEGs)between the high and low expression levels of MUTYH significantly enriched in the trace ligand-receptor interaction,cell cycle,oocyte meiosis,gap junction,and DNA replication.Group analysis revealed the signals of their open access.The neuron system,M phase,DNA repair,Rho GTPase effector,and cell cycle checkpoints were significantly enriched.ssGSEA showed a positive correlation between MUTYH expression and the infiltration levels of Th2 cells,NK cells,and T helper cells.Moreover,a negative correlation was found between MUTYH expression and the infiltration levels of dendritic cells(DCs)and cytotoxic cells.Conclusio

关键词： MUTYH Hepatocellular carcinoma(HCC) Bioinformatics Prognostic biomarker Immune infiltrates

Design method of organizational structure for MAVs and UAVs heterogeneous team with adjustable autonomy

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Journal of Systems Engineering and Electronics 2018年第2期29卷 286-295页

作者： CHEN Jun qiu Xunjie RONG Jia GAO xiaoguang School of Electronics and Information Northwestern Polytechnical University Centre of Applied Informatics College of Engineering and Science Victoria University

The increasingly complex battlefield environment requests much closer connection in a team having both manned and unmanned aerial vehicles(MAVs and UAVs). This special heterogeneous team structure causes demands for effective organizational structure design solutions. Implementing adjustable autonomy in the organizational structure, the expected evaluation function is established based on the physical resource, intelligent resource, network efficiency, network vulnerability and task execution reliability. According to the above constraints, together with interaction latency, decision-making information processing capacity, and decision-making latency, we aim to find a preferential organizational structure. The proposed organizational structure includes cooperative relationships, supervisory control relationships, and decision-making authorization relationships. In addition,by considering the influence on the intelligent support capabilities and the task execution reliability created by adjustable autonomy, it helps to build the proposed organizational structure designed with certain degree of flexibility to deal with the potential changes in the unpredictable battlefield environment. Simulation is conducted to confirm our design to be valid. And the method is still valid under different battlefield environments and interventions.

关键词： organizational structure cooperative relationship supervisory control relationship decision-making authorization relationship adjustable autonomy

Fast cross-linking by DOPA2 promotes the capturing of a stereospecific protein complex over nonspecific encounter complexes

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Biophysics Reports 2022年第Z1期8卷 239-252页

作者： Jian-Hua Wang Zhou Gong Xu Dong Shu-Qun Liu Yu-Liang Tang xiaoguang Lei Chun Tang Meng-qiu Dong National Institute of Biological Sciences (NIBS) Tsinghua Institute of Multidisciplinary Biomedical Research Tsinghua University State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of Sciences State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan Yunnan University Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular EngineeringCenter for Quantitative BiologyPeking-Tsinghua Center for Life SciencePeking University

Transient and weak protein–protein interactions are essential to many biochemical reactions, yet are technically challenging to study. Chemical cross-linking of proteins coupled with mass spectrometry analysis(CXMS) provides a powerful tool in the analysis of such interactions. Central to this technology are chemical cross-linkers. Here, using two transient heterodimeric complexes EIN/HPr and EIIAGlc/EIIBGlc as our model systems, we evaluated the effects of two amine-specific homo-bifunctional cross-linkers with different reactivities. We showed previously that DOPA2(di-ortho-phthalaldehyde with a di-ethylene glycol spacer arm) cross-links proteins 60–120 times faster than DSS(disuccinimidyl suberate). We found that though most of the intermolecular cross-links of either cross-linker are consistent with the encounter complexes(ECs), an ensemble of short-lived binding intermediates,more DOPA2 intermolecular cross-links could be assigned to the stereospecific complex(SC), the final lowest-energy conformational state for the two interacting proteins. Our finding suggests that faster cross-linking captures the SC more effectively and cross-linkers of different reactivities potentially probe protein–protein interaction dynamics across multiple timescales.

关键词： Chemical cross-linking Mass spectrometry Transient protein–protein interaction Encounter complexes Stereospecific complex Cross-linker DOPA2 DSS