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重载铁路轨道路基系统动位移空间分布特征

同济大学学报（自然科学版） 2016年第11期44卷 1709-1715页

作者：杨新文龙天航周顺华同济大学道路与交通工程教育部重点实验室上海201804

建立了重载货车-有砟轨道-路基系统耦合动力学模型.分析计算了在轨道随机不平顺激励下30t轴重重载铁路轨道-路基系统动位移的分布规律.计算结果表明:(1)轨道-路基系统各结构层动位移状态较为复杂,在重载货车通过的过程中,所受荷载也处... 详细信息

建立了重载货车-有砟轨道-路基系统耦合动力学模型.分析计算了在轨道随机不平顺激励下30t轴重重载铁路轨道-路基系统动位移的分布规律.计算结果表明:(1)轨道-路基系统各结构层动位移状态较为复杂,在重载货车通过的过程中,所受荷载也处于循环往复的加载和卸载状态.(2)在有砟轨道-路基系统的动位移的3个位移分量中,竖向动位移的幅值较大,横向动位移以及纵向动位移的幅值均不超过竖向动位移幅值的6%;而沿横向,动位移的分布较为缓和,其最大波动幅值不超过0.2mm,可近似看做均匀分布.(3)轨道-路基系统动位移沿竖向的变化,大体分为3个阶段:在钢轨到轨枕之间,出现明显突变;在轨枕层区域的衰减幅度较小;在道床层至基床表层及下部结构,竖向动位移表现为沿深度方向不断衰减,并且衰减速率随着深度的增加也在不断减小.

关键词：重载铁路轨道结构路基动位移空间分布

Influence of cyclic ignition and steady-state operation on a 1–2 A barium tungsten hollow cathode

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Plasma Science and Technology 2024年第12期26卷 121-131页

作者： Fufeng WANG tianhang MENG Zhongxi NING Ximing ZHU Harbin Institute of Technology Harbin 150001People’s Republic of China

Booming low-power electric propulsion systems require 1–2 A hollow *** cathodes are expected to go through more frequent ignitions in the low orbit,but the impact of cyclic ignitions on such 1–2 A barium tungsten hollow cathodes with a heater was not *** this study,a 12,638-cyclic ignition test and a 6,000-hour-long life test on two identical cathodes were carried *** discharge voltage of the cathode and the erosion of the orifice after cyclic ignition were all larger than that of the cathode after stable *** indicated that the impact of cycle ignition on the discharge performance of a low current BaO-W cathode with a heater was higher than that of stable *** results of the ion energy distribution function measured during the ignition period indicated that the main reason for the orifice expansion was ion ***,it was necessary to pay attention to the number of ignitions for the lifetime of this kind of cathode.

关键词： hollow cathode cyclic ignition stable operation orifice ion bombardment

Co3O4 nanocage derived from metal-organic frameworks: An excellent cathode catalyst for rechargeable Li-O2 battery

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Nano Research 2019年第7期12卷 1555-1562页

作者： Zhuoliang Jiang Hui Sun Wenke Shi tianhang Zhou Jianyong Hu Jingyang Cheng Pengfei Hu Shigang Sun State Key Laboratory of Heavy Oil Processing Beijing Key Laboratory of biogas upgrading utilizationCollege of New Energy and MaterialsChina University of Petroleum-BeijingBeijing 102249China State Key Lab of PCOSS Xiamen UniversityXiamen 361005China Eduard-Zintl-Institut fur Anorganische und Physikalische Chemie Technische UniversitatDarmstadtAlarich-Weiss-Strasse 8D-64287 DarmstadtGermany

Rechargeable non-aqueous Li-O2 battery is regarded as one of the most promising energy-storage technologies on account of its high energy *** is believed that the rational design of three-dimensional (3D) architecture for catalyst is a key factor for the remarkable ***-organic frameworks (MOFs) derived materials possess excellent architecture,which is beneficial for Li-O2 *** this work,ZIF-67 is used as precursor template and calcinated under different temperature to produce Co3O4 *** the anneal treatment is under 350℃,the derived Co3O4 nanocage holds the most complete skeleton,which provides better charge transfer ability as well as O2 and Li^+ ***,the Co3O4 nanocage owns more oxygen vacancies,offering more active *** the synergistic effect of nanocage structure and active sites,the Co3O4 nanocage stably delivers a large specific capacity of 15,500 mAh·g^-1 as well as a long cycle-life of 132 cycles at limited discharge capacity of 1,000 mAh·g^-1 under discharge/charge current density of 0.5 A·g^-1.

关键词： U-O2 batteries metal-organic framework (MOF)-derived Co3O4 nanocage Co3O4 polyhedron Co3O4 particle

Fabrication of highly effective electrodes for iron chromium redox flow battery

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Nano Research 2024年第5期17卷 3988-3996页

作者： Yingchun Niu Chao Guo Yinping Liu Guangfu Wu tianhang Zhou Fangang Qu Ziji Yang Ali Heydari Chunming Xu Quan Xu State Key Laboratory of Heavy Oil Processing China University of Petroleum(Beijing)Beijing 102249China

Iron-chromium redox flow batteries(ICRFBs)have emerged as promising energy storage devices due to their safety,environmental protection,and reliable *** carbon cloth(CC),often used in ICRFBs as the electrode,provides a suitable platform for electrochemical processes owing to its high surface area and interconnected porous ***,the CC electrodes have issues,such as,insufficient electron transfer performance,which limits their industrial ***,we employed silicic acid etching to carve dense nano-porous structures on the surface of CC electrodes based on the favorable design of ICRFBs and the fundamental principles of electrode polarization *** a result,we developed a multifunctional carbon cloth electrode with abundant vacancies,notably enhancing the performance of the *** fabricated electrode showcased a wealth of defect sites and superior electronic transport properties,offering an extensive and effective reaction area for rapidly flowing *** an electrode compression ratio of 40%and the highest current density in ICRFBs so far(140 mA·cm^(-2)),the battery achieved the average energy efficiency of 81.3%,11.24%enhancement over the previously published ***,throughout 100 charge-discharge cycles,the average energy efficiency degradation was negligible(~0.04%),which has the potential to become the most promising candidate for large-scale and long-term electrochemical energy storage applications.

关键词： iron chromium redox flow battery electron carbon cloth defect site density functional theory(DFT)calculation

Synergistic effect of electrode defect regulation and Bi catalyst deposition on the performance of iron–chromium redox flow battery

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Chinese Chemical Letters 2023年第10期34卷 281-286页

作者： Quan Xu Siyang Wang Chunming Xu Xinyi Chen Senwei Zeng Chuanyuan Li Yang Zhou tianhang Zhou Yingchun Niu State Key Laboratory of Heavy Oil Processing China University of Petroleum-BeijingBeijing 102249China

Iron-chromium redox flow batteries (ICRFBs) possess advantages of high safety,long cycle time,and *** Cr^(3+)/Cr^(2+)reaction activity is suggested as one of the most promising strategies to improve the performance and prolong the lifetime of *** improve the slow reaction kinetics of the negative electrode,a type of defected carbon cloth with Bismuth (Bi) catalyst introduction is prepared by defect engineering method and electrochemical deposition,which provided defect sites and active sites to catalyze the redox couple’s reaction of ***,this modified carbon cloth adsorbs Cr(Ⅲ)hydrate more easily,which has a more stable structure and can significantly improve the performance of *** experimental analysis and theoretical calculation indicated that the modified electrode has excellent electrocatalytic ability,which can enhance the reaction rate of Cr^(3+)/Cr^(2+),improve capacity retention and stabilize cycling *** capacity degradation rate of an ICRFB single cell with the modified electrodes is just 0.23%per cycle at a current density of 140 m A/cm^(2).Additionally,the energy efficiency (EE) remains around 83%,which is 8.45%higher than that of the pristine electrode assembled battery under 60 *** work supplies a simple method to obtain a high-performance electrode material for ICRFBs and makes it a practical solution to promote ICFRBs large-scale commercialization process.

关键词： Bismuth Iron-chromium redox flow batteries (ICRFBs) Carbon cloth Electrode catalyst Defect engineering

“不折不扣”还是“灵活变通”:政策执行刚性与弹性研究的分野与整合

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中国延安干部学院学报 2020年第1期13卷 126-136页

作者：赵天航南开大学周恩来政府管理学院天津南开300350

学界对于政策"刚性执行"和"弹性执行"观点的论争长期以来无法得到根本消解。整体上,主流观点可大致分为"刚性说""弹性说"和"折中说"。"刚性说"看到了执行弱化对政策效果的消极影响,强调应坚持执行的刚性力度,论述了缺乏刚性的后果、原... 详细信息

学界对于政策"刚性执行"和"弹性执行"观点的论争长期以来无法得到根本消解。整体上,主流观点可大致分为"刚性说""弹性说"和"折中说"。"刚性说"看到了执行弱化对政策效果的消极影响,强调应坚持执行的刚性力度,论述了缺乏刚性的后果、原因和强化刚性的策略;"弹性说"关注了对执行刚性的过度约束带来了一系列负面影响,强调政策执行的多层级和多属性,主张关注地方的差异性和执行灵活性;"折中说"认为刚性与弹性的矛盾是内在的、固有的,二者不可兼得,因此主张整合二者关系,形成了"统一说""平衡说""动态协调说"等观点。后续研究宜区分公共政策所处的不同情境,明晰"刚性执行"和"弹性执行"各自发挥正向功能的条件、限度和边界,在不同的政策情景下选择适宜的执行方式。

关键词：政策执行刚性弹性政策变通

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腰椎椎间融合术后椎间融合器沉降的研究进展

中国修复重建外科杂志 2021年第8期35卷 1063-1067页

作者：赵龙曾建成谢天航濮兴孝卢雨菲四川大学华西医院骨科成都610041

目的总结腰椎椎间融合术后椎间融合器沉降的临床研究进展,以期为该并发症的防治提供参考。方法广泛查阅近年来国内外相关文献,对腰椎椎间融合术后椎间融合器沉降的定义、发生发展规律、临床意义及危险因素等相关研究进展进行总结。结果... 详细信息

目的总结腰椎椎间融合术后椎间融合器沉降的临床研究进展,以期为该并发症的防治提供参考。方法广泛查阅近年来国内外相关文献,对腰椎椎间融合术后椎间融合器沉降的定义、发生发展规律、临床意义及危险因素等相关研究进展进行总结。结果目前,椎间融合器沉降的定义尚未统一,大部分文献将其定义为术后椎间隙高度降低超过2 mm。椎间融合器沉降主要发生在术后早期。该并发症的发生从影像学上减弱了手术结果,进而影响临床效果,甚至导致手术失败。其发生与椎间融合器的尺寸和位置、术中椎体终板的处理、椎间融合器-椎间隙形态匹配情况、骨密度、体质量指数等多种因素密切相关。结论术前选择合适尺寸和外形的椎间融合器、术中尽量靠后外侧放置椎间融合器、轻柔操作防止椎体终板损伤、围术期积极抗骨质疏松治疗、教育患者适当控制体质量等,对于预防椎间融合器沉降的发生及保证良好手术效果具有重要临床意义。

关键词：腰椎椎间融合术椎间融合器沉降临床特点危险因素

人口老龄化背景下劳动力成本与全要素生产率:基于企业所有制类型的视角

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浙江大学学报（人文社会科学版） 2023年第6期53卷 71-84页

作者：薛天航肖文唐楠浙江大学区域协调发展研究中心浙江杭州310058 浙江大学经济学院浙江杭州310058 上海财经大学金融学院上海200433

推动经济增长方式由要素驱动型转换为全要素生产率(TFP)驱动型,是应对人口结构转型和劳动力成本上升的重要路径。研究发现,劳动力成本上升促进企业TFP的提升,且对不同所有制类型企业的促进作用存在非平衡性。劳动力成本上升对国有企业... 详细信息

推动经济增长方式由要素驱动型转换为全要素生产率(TFP)驱动型,是应对人口结构转型和劳动力成本上升的重要路径。研究发现,劳动力成本上升促进企业TFP的提升,且对不同所有制类型企业的促进作用存在非平衡性。劳动力成本上升对国有企业、民营企业和外资企业TFP的促进强度依次递减,递减程度随企业要素密集度的提升而提高,随所处地区市场化水平的提高而降低;劳动力成本上升削弱民营企业和外资企业TFP竞争优势,造成民营企业和外资企业产出、就业份额下降。推动市场化改革,优化各类企业主体的营商环境,有助于减少劳动力成本上升的冲击,为TFP提升和经济可持续增长释放内生动力。

关键词：人口老龄化劳动力成本全要素生产率企业所有制类型

基于错误驱动学习策略的藏语句法功能组块边界识别

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中文信息学报 2014年第5期28卷 170-175,191页

作者：王天航史树敏龙从军黄河燕李琳北京理工大学计算机学院北京100081 北京市海量语言信息处理与云计算应用工程技术研究中心北京100081 中国社会科学院民族学与人类学研究所北京100081

藏语句法功能组块分析旨在识别出藏语句子的句法成分,为后续句子级深入分析提供支持。根据藏语的语言特点,该文在藏语句法功能组块描述体系基础上,提出基于错误驱动学习策略的藏语功能组块边界识别方法。具体思路为,首先基于条件随机场(... 详细信息

藏语句法功能组块分析旨在识别出藏语句子的句法成分,为后续句子级深入分析提供支持。根据藏语的语言特点,该文在藏语句法功能组块描述体系基础上,提出基于错误驱动学习策略的藏语功能组块边界识别方法。具体思路为,首先基于条件随机场(Conditional Random Fields,CRFs)识别组块,然后分别基于转换规则的错误驱动学习(Transformation-based Error-driven Learning,TBL)及基于新特征模板的CRFs错误驱动学习进行二次识别,并对初次结果进行校正,F值分别提高了1.65%、8.36%。最后通过实验分析,进一步将两种错误驱动学习机制融合,在18 073词级的藏语语料上开展实验,识别性能进一步提高,准确率、召回率与F值分别达到94.1%、94.76%与94.43%,充分验证了本文提出方法的有效性。

关键词：错误驱动学习藏语句法功能组块组块边界识别 CRFs TBL