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Low-Frequency Stability Analysis of Power Electronic Traction Transformer Based Train-Network System

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1608-1617页

作者： Yi Hong yang Li Zhikang Shuai Hanyu yang College of Electrical and Information Engineering Hunan University and the Advanced Energy Technology Center of State Grid Shanghai Energy Interconnection Research Institute Co.Ltd.Shanghai 201203China College of Electrical and Information Engineering Hunan UniversityChangsha 410082China College of Electrical Engineering and Controal Science in Nanjing Tech University Nanjing 211816China

Power electronic traction transformers(PETTs)will be increasingly applied to locomotives in the future for their small volume and light ***,similar to conventional trains,PETTs behave as constant power loads and may cause low-frequency oscillation(LFO)to the train-network *** solve this issue,a mathematical model of the PETT is firstly proposed and verified based on the extended describing function(EDF)method in this *** the proposed model,the LLC converter is simplified to an equivalent circuit consisting of a capacitor and a resistor in *** is further demonstrated that the model can apply to various LLC converters with different topologies and ***,when the parameter differences between cells are not obvious,the PETT can be simplified to a single-phase rectifier(i.e.,conventional train)by equivalent *** on the model of PETT,the system low-frequency stability and influential factors are analyzed by using the generalized Nyquist ***,the correctness and accuracy of theoretical analyses are validated by off-line and hardware-in-the-loop simulation results.

关键词： Extended describing function method impedance model low-frequency oscillation power electronic traction transformer train-network system

Pressure effects on metal/covalent-organic frameworks:structural and optical properties

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Science China Chemistry 2024年第9期67卷 2890-2903页

作者： Yixuan Wang Yunfeng yang Xinyi yang Bo Zou Synergetic Extreme Condition High-Pressure Science Center State Key Laboratory of Superhard MaterialsCollege of PhysicsJilin UniversityChangchun 130012China

Metal-organic frameworks(MOFs)and covalent organic frameworks(COFs)with highly ordered porous structure,tunable bandgap,large specific surface area and structural diversity,provide an appealing platform for the development of stimulus response,sensing,imaging and *** various tuning methods,pressure engineering using the diamond anvil cell is a highly powerful in-situ technique,which can efficiently modulate the structural and optical properties of MOFs/*** is beyond the realization of traditional chemical *** review outlines the research progress in the experimentoriented discovery of new phases or unique properties under high pressure,including phase transition,abnormal compression,photoluminescence(PL)discoloration and ***,the improvement of PL quantum yield in MOFs could be achieved by pressure-treated engineering and hydrogen-bonding cooperativity *** also propose and establish the relationship between structure and optical properties under high ***,the challenge and outlook of the current fields are *** hope that this review will supply guidance for comprehending the development of high-pressure MOF/COF-related research fields,and offer novel strategies for designing more high-performance MOF/COF materials to ultimately expand their applications.

关键词： metal/covalent-organic frameworks pressure engineering phase transition abnormal compressive behaviors piezochromic behaviors emission enhancement

Enhanced Ion-Selective Diffusion Achieved by Supramolecular Interaction for High Thermovoltage and Thermal Stability

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Energy & Environmental Materials 2024年第2期7卷 204-212页

作者： Jiale Ke Xing Zhao Jie yang Kai Ke Yu Wang Mingbo yang Wei yang College of Polymer Science and Engineering Sichuan University State Key Laboratory of Polymer Materials Engineering

Thermoelectric（TE） generators capable of converting thermal energy into applicable electricity have gained great popularity among emerging energy conversion ***-based ionic thermoelectric（i-TE）materials are promising candidates for energy conversion systems because of their wide sources,innocuity,and low manufacturing ***,common physically crosslinked biopolymer gels induced by single hydrogen bonding or hydrophobic interaction suffer from low differential thermal voltage and poor thermodynamic ***,we develop a novel i-TE gel with supramolecular structures through multiple noncovalent interactions between ionic liquids（ILs） and gelatin molecular *** thermopower and thermoelectric power factor of the ionic gels are as high as 2.83 mV K-1and 18.33 μW m-1K-2,*** quasi-solid-state gelatin-[EMIM]DCA i-TE cells achieve ultrahigh 2 h output energy density(E2h=9.9 mJ m-2) under an optimal temperature ***,the remarkable stability of the supramolecular structure provides the i-TE hydrogels with a thermal stability of up to 80 ℃.It breaks the limitation that biopolymer-based i-TE gels can only be applied in the low temperature range and enables biopolymer-based i-TE materials to pursue better performance in a higher temperature range.

关键词： biopolymer gel ionic liquid multiple noncovalent interactions supramolecular structure thermoelectric conversion

Atomic-level coupled RuO_(2)/BaRuO_(3) heterostructure for efficient alkaline hydrogen evolution reaction

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Journal of Energy Chemistry 2024年第1期88卷 356-362,I0009页

作者： Yueying Yan Tian Meng Yuting Chen yang yang Dewen Wang Zhicai Xing Xiurong yang State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022JilinChina School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026AnhuiChina

The slow water dissociation is the rate-determining step that slows down the reaction rate in alkaline hydrogen evolution reaction(HER).Optimizing the surface electronic structure of the catalyst to lower the energy barrier of water dissociation and regulating the binding strength of adsorption intermediates are crucial strategy for boosting the catalytic performance of *** this study,RuO_(2)/BaRuO_(3)(RBRO)heterostructures with abundant oxygen vacancies and lattice distortion were in-situ constructed under a low temperature via the thermal decomposition of *** RBRO heterostructures obtained at 550℃ exhibited the highest HER activity in 1 M KOH,showing an ultra-low overpotential of 16 mV at 10 mA cm^(-2)and a Tafel slope of 33.37 m V dec^(-1).Additionally,the material demonstrated remarkable durability,with only 25 mV of degradation in overpotential after 200 h of stability testing at 10 mA cm^(-2).Density functional theory calculations revealed that the redistribution of charges at the heterojunction interface can optimize the binding energies of H*and OH*and effectively lower the energy barrier of water *** research offers novel perspectives on surpassing the water dissociation threshold of alkaline HER catalysts by means of a systematic design of heterogeneous interfaces.

关键词： Heterostructure Hydrogen evolution reaction Interfacial electron transfer Oxygen vacancies

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氧含量对煤体低温氧化过程中自由基的影响

中国科技论文 2022年第9期17卷 1043-1048页

作者：李尽辉杨胜强蒋孝元中国矿业大学安全工程学院江苏徐州221116 煤炭资源与安全开采国家重点实验室(中国矿业大学) 江苏徐州221116

针对不同地质条件所形成的不同变质程度的煤体,为了探究矿井采空区不同氧含量对煤低温氧化过程中自由基变化的影响规律,通过配置不同氧含量的混合气体,测定褐煤、烟煤和无烟煤在不同氧含量下的自由基变化特性,从而对不同变质程度的煤体... 详细信息

针对不同地质条件所形成的不同变质程度的煤体,为了探究矿井采空区不同氧含量对煤低温氧化过程中自由基变化的影响规律,通过配置不同氧含量的混合气体,测定褐煤、烟煤和无烟煤在不同氧含量下的自由基变化特性,从而对不同变质程度的煤体在不同氧含量下的自燃特性进行分析。结果表明:不同变质程度的煤体在无氧氛围下均能发生自由基反应;随着氧含量的增加,褐煤线宽升高,烟煤、无烟煤线宽降低,3种煤体的g因子、自由基浓度和自由基浓度相对增长率均增大。通过分析,提出以自由基浓度相对增长率和g因子代替自由基浓度来评价煤体的自燃氧化能力,且得出褐煤中的自由基反应较高变质程度的烟煤和无烟煤具有更强的氧气敏感性。

关键词：低温氧化自燃灾害自由基反应 g因子

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单一厚煤层综掘面瓦斯涌出规律预测研究

中州煤炭 2011年第12期 11-13页

作者：武帅杨胜强中国矿业大学安全工程学院江苏徐州221008

对鹤壁煤电公司六矿2143工作面运输巷、回风巷综掘工作面进行了实测分析,掌握了两巷综掘面瓦斯涌出规律,在此基础上得到了煤壁和落煤瓦斯涌出的回归曲线方程,提出了适合鹤壁煤电公司六矿的综掘工作面瓦斯涌出规律预测技术。

关键词：单一厚煤层综掘工作面瓦斯涌出规律预测技术

Study of 26 Galactic Open Clusters with Extended Main-sequence Turnoffs

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Research in Astronomy and Astrophysics 2024年第6期24卷 28-37页

作者： yang-yang Deng Zhong-Mu Li Yunnan Observatories Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China Institute of Astronomy and Information Dali UniversityDali 671003China

Recent studies indicate that some Galactic open clusters(OCs)exhibit extended main-sequence turnoff(eMSTO)in their color–magnitude diagrams(CMDs).However,the number of Galactic OCs with eMSTO structures detected so far is limited,and the reasons for their formation are still *** work identifies 26 Galactic OCs with undiscovered eMSTOs and investigates the causes of these *** population types and fundamental parameters of cluster samples are acquired using CMD fitting *** them,the results of 11 OCs are reliable as the observed CMDs are *** propose the crucial role of stellar binarity and confirm the importance of stellar rotation in reproducing eMSTO *** results also show that the impact of age spread is important,as it can adequately explain the structure of young OCs and fit the observed CMDs of intermediate-age OCs better.

关键词： (stars:)binaries:general Galaxy:fundamental parameters (Galaxy:)open clusters and associations:general (stars:)Hertzsprung Russell and C-M-diagrams

Livelihood Vulnerability and Adaptation for Households Engaged in Forestry in Ecological Restoration Areas of the Chinese Loess Plateau

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Chinese Geographical Science 2024年第5期34卷 849-868页

作者： yang Qingqing CHEN yang LI Xiaomin yang Jie GAO Yanhui Northwest Land and Resources Research Center Global Regional and Urban Research InstituteShaanxi Normal UniversityXi’an 710119China School of Geographical Science and Tourism Shaanxi Normal UniversityXi’an 710119China School of Tourism and Research Institute of Human Geography Xi’an International Studies UniversityXi’an 710128China

Chinese Loess Plateau has achieved a win-win situation concerning ecological restoration and socio-economic ***,synergistic development may not be realized at the local *** areas undergoing ecological restoration,livelihood vulner-ability may be more pronounced due to the inflexibility,policy protection,and susceptibility to climate and market changes in forestry *** this issue has attracted academic interest,empirical studies are relatively *** study,centered on Jiaxian County,Shaanxi Province of China explored the households’livelihood vulnerability and coping strategies and group heterogeneity con-cerned with livelihood structures or forestry resources through field investigation,comprehensive index assessment,and nonparametric *** showed that:1)the percentage of households with high livelihood vulnerability indicator(LVI)(>0.491)reached 46.34%.2)Eight groups in livelihood structures formed by forestry,traditional agriculture,and non-farm activities were significantly different in LVI,land resources(LR),social networks(SN),livelihood strategies(LS),housing characteristics(HC),and socio-demo-graphic profile(SDP).3)The livelihood vulnerability of the groups with highly engaged/reliance on jujube(Ziziphus jujuba)forest demonstrated more prominent livelihood vulnerability due to the increased precipitation and cold market,where the low-engaged with reliance type were significantly more vulnerable in LVI,SDP,LR,and HC.4)The threshold of behavioral triggers widely varied,and farmers dependent on forestry livelihoods showed negative coping ***,the cutting behavior was strongly associated with lagged years and government subsidies,guidance,and high returns of ***,the findings can provide guidance on the dir-ection of livelihood vulnerability mitigation and adaptive government management in ecologically restored *** issue of farmers’livelihood sustainability in the context of ecologi

关键词： livelihood vulnerability forestry coping behaviors climate change market change Jiaxian County

脉冲通风法治理“U”型工作面上隅角瓦斯积聚的理论及技术探讨

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中国安全科学学报 2000年第3期10卷 48-53页

作者：杨胜强俞启香王凯张仁贵中国矿业大学

针对生产现场出现的“U”型采煤工作面上隅角瓦斯积聚问题 ,科学地分析了其形成的原因及目前解决上隅角瓦斯积聚的常用方法 ,提出了旋转脉冲法解决此问题的新途径 ,并进行了详细的理论分析。通过现场实验 ,验证了用旋转脉冲法解决上隅... 详细信息

针对生产现场出现的“U”型采煤工作面上隅角瓦斯积聚问题 ,科学地分析了其形成的原因及目前解决上隅角瓦斯积聚的常用方法 ,提出了旋转脉冲法解决此问题的新途径 ,并进行了详细的理论分析。通过现场实验 ,验证了用旋转脉冲法解决上隅角瓦斯积聚是有效的、可行的。

关键词：通风 “U”型采煤工作面隅角瓦斯积聚旋转脉冲法煤层开采安全生产