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Mechanical properties and influence mechanism of confined concrete arches in high-stress tunnels

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International Journal of Mining Science and Technology 2023年第7期33卷 829-841页

作者： Bei Jiang Zhongxin Xin Xiufeng Zhang Yusong Deng Mingzi Wang shidong li Wentao Ren State Key Laboratory for Geo-mechanics and Deep Underground Engineering China University of Mining and Technology-BeijingBeijing 100083China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China Research Center of Geotechnical and Structural Engineering Shandong UniversityJinan 250061China Shandong Energy Group Co. Ltd.Jinan 250014China

Deep underground projects(e.g., coal mines), are often faced with complex conditions such as high stress and extremely soft rock. The strength and rigidity of the traditional support system are often insufficient,which makes it difficult to meet the requirements of ground control under complex conditions. As a new support form with high strength and rigidity, the confined concrete arch plays an important role in controlling the rock deformation under complex conditions. The section shape of the tunnel has an important impact on the mechanical properties and design of the support system. However, studies on the mechanical properties and influence mechanism of the new confined concrete arch are rarely reported. To this end, the mechanical properties of traditional U-shaped steel and new confined concrete arches are compared and comparative tests on arches of circular and straight-leg semicircular shapes in deep tunnels are conducted. A large mechanical testing system for underground engineering support structure is developed. The mechanical properties and influence mechanism of confined concrete arches with different section shapes under different loading modes and cross-section parameters are systematically studied. Test results show that the bearing capacity of the confined concrete arch is 2.10 times that of the U-shaped steel arch, and the bearing capacity of the circular confined concrete arch is 2.27 times that of the straight-leg semicircular arch. Among the various influencing factors and their engineering parameters,the lateral stress coefficient has the greatest impact on the bearing capacity of the confined concrete arch,followed by the steel pipe wall thickness, steel strength, and core concrete strength. Subsequently, the economic index of bearing capacity and cost is established, and the optimization design method for the confined concrete arch is proposed. Finally, this design method is applied to a high-stress tunnel under complex conditions, and the d

关键词： High-stress tunnel Confined concrete arch Section shape Mechanical properties Design method

The Mars rover subsurface penetrating radar onboard China's Mars 2020 mission

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Earth and Planetary Physics 2020年第4期4卷 345-354页

作者： Bin Zhou ShaoXiang Shen Wei Lu Qing liu ChuanJun Tang shidong li GuangYou Fang Key Laboratory of Electromagnetic Radiation and Detection Technology Chinese Academy of SciencesBeijing 100190China Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100190China

China's Mars probe,named Tianwen-1,including an orbiter and a landing rover,will be launched during the July-August 2020 Mars launch *** to be among the rover payloads is a Subsurface Penetrating Radar module(RoSPR).The main scientific objective of the RoSPR is to characterize the thickness and sub-layer distribution of the Martian *** RoSPR consists of two *** low frequency channel of the RoSPR will penetrate the Martian soil to depths of 10 to 100 m with a resolution of a few *** higher frequency channel will penetrate to a depth of 3 to 10 m with a resolution of a few *** paper describes the design of the instrument and some results of field experiments.

关键词： SPR Mars Rover LFM subsurface China's Mars 2020

Tuning Structural and Electronic Configuration of FeN_(4) via External S for Enhanced Oxygen Reduction Reaction

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Energy & Environmental Materials 2024年第2期7卷 93-101页

作者： shidong li lixue Xia Jiantao li Zhuo Chen Wei Zhang Jiexin Zhu Ruohan Yu Fang liu Sungsik Lee Yan Zhao liang Zhou liqiang Mai State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Foshan 528200China Chemical Sciences and Engineering Division Argonne National Laboratory9700 South Cass AvenueLemontIL 60439USA NRC(Nanostructure Research Centre) Wuhan University of TechnologyWuhan 430070China X-ray Science Division Advanced Photon SourcesArgonne National Laboratory9700 South CassAvenueLemontIL 60439USA State Key Laboratory of Silicate Materials for Architectures International School of Materials Science and EngineeringWuhan University of TechnologyWuhan 430070China The Institute of Technological Sciences Wuhan UniversityWuhan 430072China Hubei Longzhong Laboratory Xiangyang 441000China

The Fe-N-C material represents an attractive oxygen reduction reaction electrocatalyst,and the FeN_(4)moiety has been identified as a very competitive catalytic active *** tuning of the coordination structure of FeN_(4)has an essential impact on the catalytic ***,we construct a sulfur-modified Fe-N-C catalyst with controllable local coordination environment,where the Fe is coordinated with four in-plane N and an axial external *** external S atom affects not only the electron distribution but also the spin state of Fe in the FeN_(4)active *** appearance of higher valence states and spin states for Fe demonstrates the increase in unpaired *** the above characteristics,the adsorption and desorption of the reactants at FeN_(4)active sites are optimized,thus promoting the oxygen reduction reaction *** work explores the key point in electronic configuration and coordination environment tuning of FeN_(4)through S doping and provides new insight into the construction of M-N-C-based oxygen reduction reaction catalysts.

关键词： coordination structure electronic configuration FeN_(4)moiety oxygen reduction reaction sulfur doping

The Development Process,Current Situation and Prospects of the Conversion of Farmland to Forests and Grasses Project in China

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Journal of Resources and Ecology 2022年第1期13卷 120-128页

作者： li shidong liU Moucheng National Forestry and Grassland Administration of China Beijing 100714China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China

The Conversion of Farmland to Forests and Grasses Project is the most symbolic and globally important ecological engineering effort to build the human and natural life *** the call and mobilization stage since the founding of the People’s Republic of China,the first round of Conversion of Farmland to Forests and Grasses occurred at the end of the 20 th *** the second round of Conversion of Farmland to Forests And Grasses launched in 2014,the central government has invested 535.3 billion yuan altogether by 2020,and 34.83 million ha have been returned to forest and grassland in 25 provinces(autonomous regions and municipalities)(2435 counties included).Among them,14.23 million ha were returned from farmland;barren hills and wasteland afforestation accounted for 17.53 million ha;and sealed mountain forest cultivation represented 3.07 million ha,accounting for 40%of the total afforestation area of national key projects in the same period,and 41 million households and 158 million farmers benefited *** project construction has made great *** total value of ecological benefits has reached 1.42 trillion yuan,plus economic benefits of 0.26 trillion yuan,and social benefits of 0.73 trillion yuan,for a total amount of 2.41 trillion *** effort has made outstanding contributions toward building an ecological civilization and a beautiful *** forward to the future,the Conversion of Farmland to Forests and Grasses will embark on a new stage of high-quality development,which will strive to achieve high-quality construction,high efficiency and a high level of *** will promote the third round of conversion of farmland to forest and grassland from 2021 to 2035,and it is expected to return 6.67 million ha to forests and grasses.

关键词： Conversion of Farmland to Forests and Grasses development process current situation construction achievement strategic task

手术室护士挑战性-阻碍性压力与心理资本、情绪劳动的关系研究

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卫生职业教育 2025年第1期43卷 115-118页

作者：何雪冬谢楠李茜茜李世东刘瑶胡文罗金芳廖想遂宁市中心医院四川遂宁629000 德阳市人民医院四川德阳618000

目的调查分析手术室护士挑战性-阻碍性压力与心理资本、情绪劳动现状及关系。方法采用滚雪球抽样法,选取三级医院符合纳入排除标准的手术室护士作为研究对象,使用一般资料调查表、挑战性-阻碍性压力量表、心理资本量表和情绪劳动量表收... 详细信息

目的调查分析手术室护士挑战性-阻碍性压力与心理资本、情绪劳动现状及关系。方法采用滚雪球抽样法,选取三级医院符合纳入排除标准的手术室护士作为研究对象,使用一般资料调查表、挑战性-阻碍性压力量表、心理资本量表和情绪劳动量表收集数据进行分析。结果手术室护士挑战性-阻碍性压力量表、情绪劳动量表、心理资本量表总分分别为(38.65±6.87)分、(50.01±10.51)分、(96.33±16.91)分。挑战性压力与心理资本各维度、情绪劳动的深层扮演和情绪表达要求维度呈显著正相关关系;阻碍性压力与心理资本各维度、情绪劳动的深层扮演维度呈显著负相关关系,与情绪劳动的情绪表达要求、表层扮演维度呈显著正相关关系。多元线性回归分析结果显示,韧性和情绪表达要求对挑战性压力起正向预测作用,情绪表达要求对阻碍性压力同样起正向预测作用,乐观对阻碍性压力起负向调节作用。结论手术室护士挑战性-阻碍性压力属于中等偏上水平,以挑战性压力为主,这与其具备较高的心理资本、情绪劳动以深层扮演为主要方式有直接关系。

关键词：手术室护士挑战性-阻碍性压力心理资本情绪劳动

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中国和美国国家公园时空发展及驱动因素

生物多样性 2023年第6期31卷 199-206页

作者：李世东国家林业和草原局科学技术司北京100714

作为世界上最大的发展中国家和发达国家,代表东西方文明的中国和美国,在反映一个国家文明与进步重要标志的国家公园建设方面,都取得了重要成果。我国国家公园建设还处于起步阶段,研究借鉴世界上国家公园首创国家的发展经验,充分发挥后... 详细信息

作为世界上最大的发展中国家和发达国家,代表东西方文明的中国和美国,在反映一个国家文明与进步重要标志的国家公园建设方面,都取得了重要成果。我国国家公园建设还处于起步阶段,研究借鉴世界上国家公园首创国家的发展经验,充分发挥后发优势,对我国国家公园的健康持续发展具有重要的理论和现实意义。本文采取综合归纳与深入调研相结合、定性分析与定量分析相结合、历史成果与现实需求相结合的研究方法,在全面分析中美两国国家公园发展进程基础上,对其内涵与外延、建设理念、发展阶段、空间格局、驱动因素等进行了系统研究。结果表明,中美两国在国家公园的基本概念与基本理念、时空发展演变、演变驱动因素等方面既有许多共同点,也有不少独特性。中美国家公园基本概念与建设理念具有异曲同工之妙,且均是由国家公园、国家公园体系、自然保护地体系构成。中国比美国国家公园建设虽然晚了100多年,但具有强大的按照中长期发展战略落实到位的后发优势,到2035年中国基本实现现代化时,将在国家公园数量、规模、空间分布、综合能力等方面达到甚至赶超美国。中美国家公园驱动因素均包括画家启蒙、学者呼吁、政府发力、社会协力和科技助力等5个主要方面,共同推动国家公园建设健康持续发展。中美国家公园建设如能求同存异,则能互利共赢,共同推动人类文明和谐进步。

关键词：国家公园国家公园体系基本理念发展阶段空间格局驱动因素

“过而改之,善莫大焉”——岂能以“动机不纯”为剽窃辩护?

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科学对社会的影响 2006年第1期50卷 47-48页

作者：李世洞武汉大学历史学院

在最近反对剽窃等学术不端的事件中，人们稍加注意就会发现一个有趣的现象。这就是那些被揭露有剽窃行为者及为其“打抱不平者”。往往是不愿或不敢刚“以事实对事实”或者用“以法规对法规”的办法答复揭露者并为自己辩护．而是用转移... 详细信息

在最近反对剽窃等学术不端的事件中，人们稍加注意就会发现一个有趣的现象。这就是那些被揭露有剽窃行为者及为其“打抱不平者”。往往是不愿或不敢刚“以事实对事实”或者用“以法规对法规”的办法答复揭露者并为自己辩护．而是用转移读者视线的办法极力渲染“揭露者动机不纯”。

关键词：学术剽窃学术监督动机语言学

植物医学:我国农业现代化进程中的病害治理挑战、机遇和创新

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植物保护 2022年第2期48卷 1-8,15页

作者：李世东中国农业科学院植物保护研究所北京100193

在我国的农业现代化进程中,病害问题已经演变成为制约我国种植业可持续发展的重要因素之一,而建立在“病原学说”基础之上的病理学理论以及在其指导下形成的各类以“杀(抑)菌”为首要目标的防治措施难以应对当前病害严重发生的复杂局面... 详细信息

在我国的农业现代化进程中,病害问题已经演变成为制约我国种植业可持续发展的重要因素之一,而建立在“病原学说”基础之上的病理学理论以及在其指导下形成的各类以“杀(抑)菌”为首要目标的防治措施难以应对当前病害严重发生的复杂局面。本文剖析了当前我国农业生产上病害严重发生的原因,认为主要是由于生产者在经济利益的驱动下,主观上对土、肥、水等自然资源进行掠夺性经营,实践中采取连年单一种植和化学品持续大量投入等不良栽培措施,导致农田理、化、生物学性状严重劣化和生态失衡,从而引发作物严重衰弱、“易感”和环境的极端“利病”所致。基于此,笔者倡导以重视寄主生理状态和不良环境因素的影响为重要内容的病害发生的“全面病因学说”以及以此为核心内容和基础的“植物保健医学”的发展,并对相关概念、历史和成功案例作了简介。在具体防病实践上笔者倡导以健康栽培为核心的作物病害综合治理策略及其应用,即一方面设法减少传统“病原物”的数量累积和阻断侵染,另一方面更加注重农田生态系统中理、化和生物学性状的改善,以重塑、促进和维护农田生态平衡,进而实现增强寄主抗性、促进寄主植物生长和防病治病的目标。上述观点是对传统病理学病害防治理论的补充、完善和必要的修正,对我国现代农业的可持续发展具有重要意义。

关键词：农业现代化病害病原学说植物医学可持续发展

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DISTRIBUTION PATTERNS OF LEAF AREA INDEX FOR MAJOR CONIFEROUS FOREST TYPES IN CHINA

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Journal of Geographical Sciences 1997年第4期7卷 61-73页

作者： Luo Tianxiang li Wenhua Zhao shidong Commission for Integrated Survey of Natural Resources, CAS, Beijing 100101 The People’s Republic of China

Leaf area index (LAI) of natural vegetation is recognized as the most important variable for measuring vegetation structure over large areas, and for relating it to energy and mass exchange, which has been successfully estimated from satellite resolution sensors. In this paper, according to the statistical analysis based on a lot of forest plots, the mathematical models of LAI distribution patterns in the hydro thermal spaces for five coniferous forest types in China were established. For the cold temperate larch forests growing in the dry and cold climate, their LAI increases with the increasing of warm index and precipitation in the way of hyperbolic quadratic surface. For the cold temperate spruce fir forests and temperate Pinus tabulaeformis forests, their LAI is negatively related to the annual mean air temperature in the way of the natural exponential curve, in order to adapt to the water oppressed environments. For the subtropical Pinus massoniana forests and Cunninghamia lanceolata forests growing in the warm and moist climate, their LAI is related to the annual mean air temperature in the way of the parabolic quadratic curve.

关键词： leaf area index hydro thermal space distribution pattern.