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Dynamic propagation velocity of a positive streamer in a 3 m air gap under lightning impulse voltage

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Plasma Science and Technology 2024年第4期26卷 114-121页

作者：李志伟雷挺苏宇姚修远杨冰雪刘德龙律方成丁玉剑 North China Electric Power University Beijing 102206People’s Republic of China China Electric Power Research Institute Beijing 100192People’s Republic of China

Streamers represent an important stage in the initiation of gap discharge. In this work, we used an eight-frame intensified charge-coupled device camera to capture the streamer development process when a lightning impulse voltage of 95%–100% U50% was applied in a 3 m rod–plate gap and the streamer velocity was analyzed. Analysis of the observations shows that streamer velocity can be defined by three stages: rapid velocity decline(stage 1), rapid velocity rise(stage 2)and slow velocity decline(stage 3). The effects of electrode shape, applied voltage and gap breakdown or withstanding on streamer velocity were analyzed. The electrode with a larger radius of curvature will result in a higher initial velocity, and a higher voltage amplitude will cause the streamer to propagate faster at stage 3. Gap withstanding or breakdown has no obvious effect on streamer velocity. In addition, the experimental results are compared with previous results and the statistical characteristics of the primary streamer discharge are discussed.

关键词： lightning impulse 3 m air gap development process streamer velocity

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气流辅助的静电纺丝技术研究进展

纺织学报 2024年第8期45卷 44-53页

作者：刘德龙王红霞林童天津工业大学纺织科学与工程学院天津300387

近年来,通过引入外部气流来增强静电纺使纳米纤维生产能力取得了显著进展,气流辅助不仅提高了静电纺丝效率,还改善了纤维的取向、堆积密度甚至形貌,已逐渐发展成为一种先进的纳米纤维制造方法。不同的气流施加方式,对静电纺丝过程具有... 详细信息

近年来,通过引入外部气流来增强静电纺使纳米纤维生产能力取得了显著进展,气流辅助不仅提高了静电纺丝效率,还改善了纤维的取向、堆积密度甚至形貌,已逐渐发展成为一种先进的纳米纤维制造方法。不同的气流施加方式,对静电纺丝过程具有不同的效果,结合不同的静电纺丝模式,使其展示独特优势,从而极大地丰富了静电纺丝技术。综述了气流辅助静电纺丝技术的研究进展,包括其基本原理、发展历程,讨论了具有代表性的气流辅助静电纺丝装置,如气流辅助的针型静电纺丝、气流辅助的无针静电纺丝、离心静电纺丝主要参数和理论模拟。对气流辅助静电纺丝技术存在的问题以及未来研究发展进行了展望。

关键词：气流辅助静电纺丝纳米纤维生产率纺丝头

董其昌重塑美术史的努力:籍倪瓒纯化文人画正脉

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美术学报 2024年第2期 105-111页

作者：刘德龙张权南京大学艺术学院

赵孟頫被移出“元四家”,通常解释为“子昂亏节”,陷入了“以人品定艺品”的窠臼,若将董其昌在元四家中“去赵孟頫入倪瓒”与其“南北宗论”联系起来看,会得出不一样的结论。结合“南北宗论”对“士夫画”和“行家画”的区分,董其昌“... 详细信息

赵孟頫被移出“元四家”,通常解释为“子昂亏节”,陷入了“以人品定艺品”的窠臼,若将董其昌在元四家中“去赵孟頫入倪瓒”与其“南北宗论”联系起来看,会得出不一样的结论。结合“南北宗论”对“士夫画”和“行家画”的区分,董其昌“去赵入倪”实则是纯化文人画正脉,扭转“院画”和“士夫画”的衰落局面,通过去除赵孟頫影响的画坛习气,追求倪瓒纯粹文人士夫的“逸品格调”和草草“逸笔”,以达到重塑文人画史,借古以开今的目的。

关键词：董其昌倪瓒赵孟頫元四家文人画

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艺术批评的边界——以名誉侵权为中心的讨论

贵州大学学报（艺术版） 2024年第2期38卷 32-38页

作者：宋亚洋刘德龙江苏泰和(泰州)律师事务所江苏泰州225300 南京大学艺术学院江苏南京210000

艺术批评中常出现从对于作品的分析评论扩展到对作者人格、行为的讨论,让艺术创作者感到人格受到冒犯,发生名誉权纠纷等法律问题。以名誉侵权为视角,厘清艺术批评中“侮辱”“诽谤”的法律界定,从司法实务案例对名誉侵权的认定中给艺术... 详细信息

艺术批评中常出现从对于作品的分析评论扩展到对作者人格、行为的讨论,让艺术创作者感到人格受到冒犯,发生名誉权纠纷等法律问题。以名誉侵权为视角,厘清艺术批评中“侮辱”“诽谤”的法律界定,从司法实务案例对名誉侵权的认定中给艺术批评找到法律“红线”,从而定位艺术批评的合法边界,对艺术批评的健康发展有重要的现实意义。

关键词：艺术批评名誉权边界

维普期刊数据库博看期刊

Dynamic Spectrum Anti-Jamming with Distributed Learning and Transfer Learning

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China Communications 2023年第12期20卷 52-65页

作者： Xinyu Zhu Yang Huang delong liu Qihui Wu Xiaohu Ge Yuan liu Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China The 723 Institute of CSSC Yangzhou 225001China School of Electronic Information and Communications Huazhong University of Science and TechnologyWuhan 430074China School of Electronic and Information Engineering South China University of TechnologyGuangzhou 510641China

Physical-layer security issues in wireless systems have attracted great *** this paper,we investigate the spectrum anti-jamming(AJ)problem for data transmissions between *** fast-changing physical-layer jamming attacks in the time/frequency domain,frequency resources have to be configured for devices in advance with unknown jamming patterns(*** time-frequency distribution of the jamming signals)to avoid jamming signals emitted by malicious *** process can be formulated as a Markov decision process and solved by reinforcement learning(RL).Unfortunately,stateof-the-art RL methods may put pressure on the system which has limited computing *** a result,we propose a novel RL,by integrating the asynchronous advantage actor-critic(A3C)approach with the kernel method to learn a flexible frequency pre-configuration ***,in the presence of time-varying jamming patterns,the traditional AJ strategy can not adapt to the dynamic interference *** handle this issue,we design a kernelbased feature transfer learning method to adjust the structure of the policy function *** results reveal that our proposed approach can significantly outperform various baselines,in terms of the average normalized throughput and the convergence speed of policy learning.

关键词： A3C anti-jamming reinforcement learning spectrum transfer learning wireless system

Nanomorphology in A–D–A type small molecular acceptors-based bulk heterojunction polymer solar cells

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Journal of Energy Chemistry 2019年第8期28卷 104-123,I0001,I0005页

作者： delong liu Ying Zhang Gang Li The Department of Electronic and Information Engineering The Hong Kong Polytechnic UniversityHong Kong 999077 China The Department of Electronic and Information Engineering The Hong Kong Polytechnic University Shenzhen Research InstituteShenzhen 518057Guangdong China

Recent developments in acceptor–donor–acceptor(A–D–A) type non-fullerene acceptors have led to substantial improvements in bulk-heterojunction polymer solar cells efficiency. The device performance strongly depends on photoactive layer morphology, as the molecular packing, donor–acceptor interface and phase separation significantly affect the charge-transfer states and charge carrier dynamics. In this review, we start with a brief introduction of the techniques most effectively utilized to characterize multiphase morphology. Then, we summarize recent progress in A–D–A type acceptors, with the emphasis on understanding the molecular structure–morphology–performance relationships. Finally, an outlook on correlating morphological characteristics with photovoltage losses is presented for further improving device performance.

关键词： Polymer solar cells Bulk heterojunction Nanomorphology Non-fullerene acceptor A–D–A type small molecules

Simultaneous Determination of Rare Earth Elements by Dual-System Iterative Target Transformation Factor Analysis

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Journal of Rare Earths 1999年第2期17卷 68-71页

作者： liu, delong Yang, Yansheng Zhongshan Univ Guangzhou China

Dualcolor systems were used to reduce the collinearity of multicomponent spectra, which is described by the angles between spectra vectors. Combined with iterative target transformation factor analysis, single rare earth element was determined in its mixture. The calculated results show that the average angle between rare earth spectra in one color system(trichloroarsenazorare earths, pH 34) is 45, and that in two color systems(trichloroarsenazorare earths, pH 34, 14) is 215. This technique makes it easy to select the real number of the components in mixtures, and the determination results show dualcolor system method is an effective technique in rare earth mixture analysis.

关键词： Rare earths Multicomponent analysis Iterative target transformation factor analysis

Mechanisms of resistance to third-generation EGFR tyrosine kinase inhibitors

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Frontiers of Medicine 2016年第4期10卷 383-388页

作者： Shuhang Wang Yongping Song Feifei Yan delong liu The Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education) Peking University Cancer Hospital Beijing 100142 China Henan Cancer Hospital and the Affiliated Cancer Hospital of Zhengzhou University Zhengzhou 450008 China

The tyrosine kinase inhibitors （TKI） of the epidermal growth factor receptor （EGFR） are becoming the first line of therapy for advanced non-small cell lung cancer （NSCLC）. Acquired mutations in EGFR account for one of the major mechanisms of resistance to the TKIs. Three generations of EGFR TKIs have been used in clinical applications. AZD9291 （osimertinib; Tagrisso） is the first and only FDA approved third-generation EGFR TKI for T790M-positive advanced NSCLC patients. However, resistance to AZD9291 arises after 9-13 months of therapy. The mechanisms of resistance to third-generation inhibitors reported to date include the EGFR C797S mutation, EGFR L718Q mutation, and amplifications of HER-2, MET, or ERBB2. To overcome the acquired resistance to AZD9291, EAI045 was discovered and recently reported to be an allosteric EGFR inhibitor that overcomes T790M- and C797S-mediated resistance. This review summarizes recent investigations on the mechanisms of resistance to the EGFR TKIs, as well as the latest development of EAI045 as a fourth-generation EGFR inhibitor.

关键词： EGFR tyrosine kinase inhibitor AZD9291 EAI045

城轨接触网动态运行质量评价指标CDI数学模型研究

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电气化铁道 2024年第2期35卷 61-66页

作者：张建昭宋伟李栓刘天龙王恩营杨新宇张森王华飞杨铭刘德龙刘亚军刘帅巩亚超北京京港地铁有限公司

接触网作为城市轨道交通牵引供电系统重要组成部分,通过与受电弓滑动接触为电客车提供持续稳定电能,因此其动态运行质量对线路安全运营至关重要。目前,城市轨道交通行业内接触网设备管理仍然以传统静态几何参数阈值管理方式为基础,仅能... 详细信息

接触网作为城市轨道交通牵引供电系统重要组成部分,通过与受电弓滑动接触为电客车提供持续稳定电能,因此其动态运行质量对线路安全运营至关重要。目前,城市轨道交通行业内接触网设备管理仍然以传统静态几何参数阈值管理方式为基础,仅能对接触网静止时的状态进行确认,较难针对带负荷工况下接触网动态性能及弓网关系进行分析。本文应用已相对成熟的车载弓网3C动态检测技术,综合考虑影响弓网动态关系的各项参量,在国家或行业标准、企业精修标准基础上,开展城市轨道交通接触网动态运行质量评价指标CDI研究,旨在构建一套科学、完善的设备动态质量评价体系与标准,将接触网动态性能进行直观量化评估,便于对服役设备的管理。

关键词：接触网动态运行质量评价体系与标准量化评估设备管理