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Observation and study on the whole process of cloud-to-ground lightning using narrowband radio interferometer

Science China Earth Sciences 2008年第5期51卷 694-708页

作者： ZHANG GuangShu ZHAO YuXiang QIE XiuShu ZHANG Tong WANG YanHui CHEN ChengPin Laboratory for Climate Environment and Disasters of Western China Cold and Arid Regions Environmental and Engineering Re-search InstituteChinese Academy of SciencesLanzhou 730000China Laboratory for Middle Atmosphere and Global Environment Observation(LAGEO) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Tianshui Normal College Tianshui 741001China

A narrowband radio interferometer has been developed and used to locate the entire sources of VHF radiations from a negative cloud-to-ground (CG) lightning discharge which contains 19 strokes. This system uses five antennas to form an array consisting of short- and long-baselines along two or- thogonal directions. The system error which comes from frequency conversion is reduced by phase detection through direct high frequency amplifying. An interactive graphic analysis procedure is used to remove the fringe ambiguities which exist inherently in interferometry and to determine the direction of lightning radiation sources in two dimensions (azimuth and elevation) as a function of time at a time resolution of microsecond orders. With the developed system, the whole progression process in time and space of a lightning flash can be reconstructed. In this paper, combining the synchronous data of electric filed change and VHF radiation, the whole processes of an example negative CG flash have been studied in detail. It is found that the preliminary breakdown event of the CG flash started from negative charge region and exhibited firstly a downward pregression and then an upward propagation. There were very intense and continuous radiations during stepped leaders which became much stronger when the first return stroke began. In contrast, there were less and only discrete radiations during dart leaders. Stepped leader and dart leader may transform to each other depending on the state of the ionization of the path. The progression speed of initial stepped leaders was about 105 ms?1, while that was about 4.1×106 and 6.0×106 ms?1 for dart leaders and dart-stepped leaders, respectively. M events produced hook-shaped field changes accompanied by active burst of radiations at their begin- nings. Followed these active radiation processes, M events appeared to contact finally into conducting main discharge channels. The mean progression speed of M events was about 7×107 ms?1, greater than that of the dart leaders and dart-step l

关键词： lightning narrowband interferometer dart leader K events M events the whole process of cloud-to-ground lightning

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An Analysis of the Development of Middle leaders in Chinese Secondary Schools:The Role of the Principal

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Journal of Contemporary Educational Research 2022年第10期6卷 98-108页

作者： Qin Zhou Department of Administration School of Economics and Social WelfareZhejiang Shuren UniversityHangzhou 310000Zhejiang ProvinceChina

Numerous studies conducted on educational leadership have generally emphasized the role of principal,whereas,research on middle leadership remains limited[1].The purpose of this paper is to explore and investigate the development of middle leadership and seeks to fill in the gap by providing the analysis from a Chinese context.The author found that middle leaders are positioning at a challenging role,in which they are required to take charge of responsibilities of both a leader and a teacher,and in the meantime,they also need to negotiate between the senior leader,the colleagues.and subordinates.Furthermore,personal factors such as self-awareness and resilience are discovered to be pivotal for middle-leadership development.Apart from that,the principal plays a critical role in establishing collaborative school culture that facilitates the development of middle leaders based on the influences from the school’s history,culture,and policies.

关键词： Educational leadership Middle leadership leader Principal Self-awareness Resilience School culture Leading learning Trust Distributed leadership

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Propagation of positive, negative, and recoil leaders in upward lightning flashes

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Earth and Planetary Physics 2019年第2期3卷 102-110页

作者： XiuShu Qie ShanFeng Yuan HongBo Zhang RuBin Jiang ZhiJun Wu MingYuan Liu ZhuLing Sun YunJiao Pu JinLiang Li Abhay Srivastava ZiLong Ma GaoPeng Lu Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO) Institute of Atmospheric Science Chinese Academy of Sciences Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of information Science & Technology College of Earth and Planetary Science University of Chinese Academy of Sciences Fujian Meteorological Service Center Fujian Meteorological Bureau

leader propagation is a fundamental issue in lightning physics. The propagation characteristics of positive leaders and negative leaders are summarized and compared based on data from high-speed camera and electromagnetic field in rocket-triggered lightning and tower-initiated lightning discharges; available channel base current data recorded in rocket-triggered lightning are also used. The negative leaders propagate in a stepped fashion accompanied by many branches. The stems ahead of the negative leader tip determine the manner and direction of the leader propagation, and even the branching and winding of the lightning channel. The impulsive current, electromagnetic field, and related optical images suggest that the positive leader may develop in a step-like fashion at its initial stage of triggered lightning. However, the stepping processes of the positive leader are obviously different from those of the negative leader. Tower-initiated lightning revealed that the most conspicuous characteristics of the stepwise positive leader involve the intermittent brush-like corona zone in front of the leader tip and the luminosity enhancement of the channel behind the tip. In rockettriggered lightning flashes, the charge transferred during an individual step for the negative leader was nearly an order greater than for the positive counterpart. The successive streamers ahead of the leader tip are essential for both negative and positive leader propagation, and the stems could be formed from one or more streamers in the previous negative streamer zone with the main leader channel dim. High-resolution observation of tower lightning also revealed a new type of bidirectional recoil leader, with polarity contrary to the traditional one, traversing in negative channels associated with tower-initiated and rocket-triggered lightning.

关键词： lightning propagation negative leader positive leader recoil leader

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China as I know It

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China Today 2023年第9期72卷 20-22页

作者： ARNAUD BERTRAND 不详

The French businessman and opinion leader shared his observations and understanding of China and its national governance.

关键词： French opinion leader

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Qui estàl'origine du piège de la dette de l'Afrique?

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今日中国（法文版） 2022年第9期60卷 41-43页

作者： DONATIEN NIYONZIMA 不详

La Chine s’est imposée en tant que leader mondial du financement du développement international au XXI^(e) siècle.La Banque des règlements internationaux la classe aujourd'hui au sixième rang mondial des créan... 详细信息

关键词： des origin leader

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Broadband interferometer observations of a triggered lightning

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Chinese Science Bulletin 2001年第18期46卷 1561-1565页

作者： DONG Wansheng LIU Xinsheng YU Ye ZHANG Yijun Cold and Arid Regions Environmental&Engineering Research Institute Chinese Academy of SciencesLanzhou 730000China School of electrical Engineering Wuhan UniversityWuhan 430072China

The development of positive leader of an artificially triggered lightning has been analyzed based on the data of electric field change, location of radiation source and frequency spectrum obtained by using the broadband interferometer system. The results indicate that radiation from positive leader could be detected within close distance in spite of the relatively weak radiation, while the radiation from negative breakdown processes was relatively stronger. Positive leader developed with few branches, and the initial progression velocity was of the order of 105 m/s. The distribution of power spectrum by 25 MHz high pass filter indicated that the radiation frequency from positive leader maximized at 25-30 MHz, while that from negative breakdown processes maximized at 60-70 MHz.

关键词： broadband interferometer system lightning discharge leader frequency spectrum.

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Snapshots of Local Buddhist Activities in 2022

The Voice of Dharma

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The Voice of Dharma 2022年第1期 164-167页

作者：无 XU Huaijing(译) Editorial Office of the Voice of Dharma 不详

The Sub-forum“Dialogue of Religious leaders”of Boao Forum for Asia Annu-al Conference 2022 Held in Boao,Hainan Province On the morning of April 22,2022,the sub-forum“Dialogue of Religious leaders”of Boao Forum for Asia(BFA)Annual Conference 2022,themed on“Civilizations Flourishing Through Exchanges and Communication”,was held in Boao,Hainan Province.

关键词： Province. Snapshot leader

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Top 10 Nation News Stories of 2022

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Beijing Review 2022年第52期65卷 12-15页

1 Xi Jinping Re-elected Top CPC leader On October 23,Xi Jinping was re-elected general secretary of the Communist Party of China(CPC)Central Committee at the First Plenary Session of the 20th CPC Central Committee.He will serve for another five years,to lead the nation to complete the tasks laid out at the 20th CPC National Congress,which was convened in Beijing from October 16 to 22.

关键词： Nation Communist leader

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National Engineering Research Center of Distillation Technology leader of distillation technology

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Chinese Journal of Chemical Engineering 2019年第6期27卷 1459-1459页

National Engineering Research Center of Distillation Technology(NERCDT), supported by Tianjin University,is authorized and awarded by National Development and Reform Commission as a national engineering research center.Pei-yang National Distillation Technology Corporation Limited(PYD),supported by the scientific research advantages of Chemical Engineering Subject of Tianjin University.

关键词： Distillation leader distillation

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“Opinion leader”一词的中文翻译探析

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西昌学院学报（社会科学版） 2018年第1期30卷 102-105页

作者：王丽闽江学院外语系福建福州350000

在我国,随着博客、微博等新媒体的飞速发展,一批民间网络名人不断涌现,成为传统意义上的Opinion leader,即"意见领袖"。但由于互联网环境下某些网络传播代表人物的不正当示范,考虑到汉语的表达习惯,"意见领袖"作为"Opinion leader"一词... 详细信息

在我国,随着博客、微博等新媒体的飞速发展,一批民间网络名人不断涌现,成为传统意义上的Opinion leader,即"意见领袖"。但由于互联网环境下某些网络传播代表人物的不正当示范,考虑到汉语的表达习惯,"意见领袖"作为"Opinion leader"一词的中文翻译,容易使公众产生错误联想,造成误解,甚至对我国网络舆论安全带来不容忽视的负面影响。

关键词： Opinion leader 意见领袖舆论导向人

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