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Critical slope gradient for compulsory abandonment of farmland on the hilly Loess Plateau

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Chinese Science Bulletin 1998年第5期43卷 409-412页

作者： TANG Keli+1, ZHANG Keli 1,2.and LEI Aling 1,3 1. Institute of Soil and water Conservation, Chinese Academy of Sciences, Yangling 712.00, china 2. Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, china 3. water Resources C Institute of Soil and water Conservation Chinese Academy of Sciences Yangling China Department of Hydraulic Engineering Tsinghua University Beijing China water Resources Conservation bureau of Yangtze River Ministry of Water Resources Wuhan China

Scientific evidence for the upper limit of farmland is proposed. Shallow gully erosion is one of erosion types distributed extensively on sloping farmland in the hilly regions of the Loess Plateau. Field observation and aerial photos interpretation, as well as laboratory experiments show that the shallow gully erosion occurring on the steeper farmland in the hilly regions of the Loess Plateau is an important factor leading to intensive erosion on slope, because of its extensive distribution and intensive runoff collection. The data on the formation, development and distribution of shallow gullies on sloping farmland indicate that critical slope gradient for shallow gully initiation ranges from 15 to 2. degrees with an average of 18.2.degrees. Therefore, it is suggested that critical slope gradient for compulsory abandonment of farmland on the hilly Loess Plateau should be kept within the critical slope gradient for shallow gully initiation to prevent shallow gully formation in order to control soil loss more effectively. But as the first step, the cultivation on the slopes with slope larger than 2. degrees where the maximum erosion occurs should be strictly forbidden.

关键词： hilly region of Loess Plateau upper limitation for farmland shallow gully erosion erosion dynamic.

Variation of karst spring discharge in the recent five decades as an indicator of global climate change: A case study at Shanxi, northern china

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Science china Earth Sciences 2005年第11期48卷 2001-2010页

作者： GUO Qinghai1, WANG Yanxin1, MA Teng1 & LI Luxiu2.1. School of Environmental Studies, china University of Geosciences, Wuhan 430074, china 2. Office of {2. Resource Management of Shanxi Province, Taiyuan 030001, china School of Environmental Studies China University of Geosciences Wuhan China Office of water Resource Management of Shanxi Province Taiyuan China

Karst in Shanxi Province is representative of that in northern china, and karst water systems discharge in the form of springs that are among the most important sources for local water supply. Since the 1950s, attenuation has been the major trend of discharge variation of most karst springs at Shanxi. Based on the case study of 7 karst springs including Niangziguan, Xin’an, Guozhuang, Shentou, Jinci, Lancun, and Hongshan springs, the discharge variation process of karst springs was divided into natural fluctuation phase and anthropogenic impact phase. Discharge attenuation of the 7 karst springs was controlled mainly by climate and human activities, with their contributions being respectively about 60% and 40%. According to the dif-ference of the effect of climate and human activities for each spring, attenuation modes of spring discharge fall into three types: natural process dominated attenuation type, exploitation induced process dominated attenuation type, and mixed attenuation type. The total restored discharge variation of 7 karst springs matched well with the global air temperature change in 1956―2.00, clearly indicating the trend of global warming and aridity in the last several decades, and the analysis of discharge variation processes of karst springs can be used as a new tool for global change studies.

关键词： karst, Shanxi, spring discharge, attenuation, climate, human activity, global change

Using soil surface gray level to determine surface soil water content

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Science china Earth Sciences 2010年第10期53卷 1527-1532页

作者： ZHU YuanJun1,2.WANG YunQiang1,2.& SHAO MingAn1,2.1 State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau,Institute of Soil and water Conservation,Northwest A & F University,Yangling 712.00,china 2.Institute of Soil and water Conservation,Chinese Academy of Sciences & Ministry of water Resources,Yangling 712.00,china State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau Institute of Soil and Water Conservation Northwest A & F University Yangling China Institute of Soil and water Conservation Chinese Academy of Sciences & Ministry of Water Resources Yangling China

How to determine surface soil water content(SWC) quickly and accurately is fundamental in studying eco-hydrological processes and their *** we use laboratory experiments to determine surface SWC using soil surface gray level(SGL) values.A negatively exponential relationship exists between SGL and SWC,i.e.,SGL increases with the decrease of *** can be estimated based on initial SGL value(surface gray level when SWC=0),SWC,and a surface roughness coefficient characterized by mean soil particle *** variation range of SGL was larger than that of SWC,indicating that changes in SWC were enhanced in SGL,and that SGL would thus be sensitive to changes in soil *** the 95% confidence level,SWC can be determined by using the relationship between SWC and SGL established by the *** determination of SWC has a high precision when SWC was between dry and saturated.

关键词： Loess Plateau soil water remote sensing surface roughness

Compression behavior of Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(2..5) bulk metallic glass up to 2. GPa

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Science china(Physics,Mechanics & Astronomy) 2005年第3期48卷 319-324页

作者： LI Gong 1, 2., ZHAN Zaiji 2., LIU Jing 3 , YUN Jinku 1 , SUN Liling 2., LIU Riping 1 , ZHANG Jun 2.& WANG Wenkui 1, 2.1. Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, china 2. Center for Condensed matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, china 3. BSRF, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039, china Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao China Center for Condensed matter Physics Institute of Physics Chinese Academy of Sciences Beijing China BSRF Institute of High Energy Physics Chinese Academy of Sciences Beijing China

The compression of a Zr41Ti14Cu12.5Ni10Be2..5 bulk metallic glass (BMG) is investigated at room temperature up to 2. GPa using in-situ high pressure energy dispersive X-ray diffraction with a synchrotron radiation source. The pressure-induced structural relaxation is exhibited. It is found that below about 8 GPa, the existence of excess free volume contributes to the rapid structural relaxation, which gives rise to the rapid volumetric change, and the structural relaxation results in the structural stiffness under higher pressure.

关键词： bulk metallic glass, high pressure, structural relaxation, synchrotron radiation.

Chinese expert consensus on the clinical application of drugcoated balloon(2.(nd) Edition)

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Journal of Geriatric Cardiology 2024年第2期21卷 135-152页

作者： The Expert Writing Committee of the Chinese Expert Consensus on Clinical Applications of Drug-Coated Balloon(2.(nd)Edition) Jun-Bo GE Yun-Dai CHEN 不详 Zhongshan Hospital Fudan University Chinese PLA General Hospital

Percutaneous coronary interventions have progressed through the era of plain balloon dilation, bare-metal stent insertion to drug-eluting stent treatment, which has significantly reduced the acute occlusion and restenosis rates of target vessels and improved patient prognosis, making drug-eluting stents the mainstream interventional treatment for coronary artery disease. In recent years, drug-coated balloons(DCBs) have become a new treatment strategy for coronary artery disease, and the drugs used in the coating and the coating technology have progressed in the past years. Without permanent implant, a DCB delivers antiproliferative drugs rapidly and uniformly into the vessel wall via the excipient during a single balloon dilation. Many evidence suggests that DCB angioplasty is an effective measure for dealing with in-stent restenosis and de novo lesions in small coronary *** more clinical studies are published, new evidence is emerging for the use of DCB angioplasty in a wide range of coronary diseases, and the indications are expanding internationally. Based on the latest research from china and elsewhere, the Expert Writing Committee of the Chinese Expert Consensus on Clinical Applications of Drug-Coated Balloon has updated the previous DCB consensus after evidence-based discussions and meetings in terms of adequate preparation of in-stent restenosis lesions, expansion of the indications for coronary de novo lesions, and precise guidance of DCB treatment by intravascular imaging and functional evaluation.

关键词： balloon drugs dealing

Trace element geochemistry of the Lower Cambrian black rock series from northwestern Hunan, South china

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Progress in Natural Science:Materials International 2004年第1期14卷 65-71页

作者： PAN Jiayong 1,2. *, MA Dongsheng 1 and CAO Shuanglin 1,2. (1.The State Key Laboratory for Mineral Deposits Research, Nanjing University, Nanjing 2.0093, china 2. East china Institute of Technology, Fuzhou 344000, china) Nanjing Univ State Key Lab Mineral Deposit Res Nanjing 210093 Peoples R China E china Inst Technol Fuzhou 344000 Peoples R China

Samples of black rock series collected from the Lower Cambrian Niutitang Formation, northwestern Hunan Province, china, were analyzed for trace elements. The trace element geochemical characteristics of the ore layer (high enrichments of Ni, Mo, V, U, Cu, Pb, Zn, Cd, Tl and Ba; high U/Th ratios and LREE enriched patterns with positive Eu and Y anomalies) support the assumption that the Ni Mo polymetallic layer is of submarine hydrothermal origin. High field strength elements (HFSE) and lithophile elements such as Nb, Ta, Zr, Hf, Li, Be, Rb, Cs, Th and Sc are remarkably higher in the upper unit than those in the lower unit of the Niutitang Formation. These features may reflect that hydrothermal contributions were diminished, and terrigenous constituents were increased in the sediments of the upper unit of the Niutitang Formation.

关键词： black rock series Early Cambrian trace elements northwestern Hunan china

A distributed hydrological model with its application to the Jinghe watershed in the Yellow River Basin

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Science china(Technological Sciences) 2004年第Z1期47卷 60-71页

作者： WANG Zhonggen1, ZHENG Hongxing1, LIU Changming1, , WU Xianfeng2.2.& ZHAO Weimin3 1. Key Laboratory of water Cycle & Related Land Surface Processes, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, china 2. Institute of Environmental Science, Beijing Normal University, Beijing 100875, china 3. water Resources Conservation Committee of Yellow River, Zhengzhou 450003, china Key Laboratory of water Cyde & Related Land Surface Processes Institute of Geographic Science and Natural Resources Research Chinese Academy of Sciences Beijing China Institute of Environmental Science Beijing Normal University Beijing China water Resources Conservation Committee of Yellow River Zhengzhou China

For the purpose of water resources management in the Yellow River Basin with highly spatial difference, a daily distributed hydrological model was proposed, of which the determination of spatially-distributed parameters and model inputs processing were performed by means of GIS/RS. In the model, the computation of runoff yield was based on the topography index method and flow routing was modeled by Maskingum method. The operation of the model is followed by means of “command structure” technique based upon the topography of river network. A case study using the model was conducted for the Jinghe watershed, which locates at the middle Yellow River Basin. The simulation of the hydrological processes in 1996 has shown that water quantity balance errors were less than 5% and the Nash-Sutcliffe coefficient arrived at 0.7, indicating that the model structure is justifiable, and the precision of the model can satisfy the purpose of water resources management.

关键词： distributed hydrological model, structure and equation, GIS and RS, Jinghe Basin, Yellow River Basin.

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AIGC应用层发展趋势研究

软件和集成电路 2024年第4期 64-75页

作者： 1.国际数据公司(IDC) 2.钉钉(中国)信息技术有限公司国际数据公司(IDC) 钉钉(中国)信息技术有限公司

AIGC作为一条为用户、企业、社会带来切实价值的AI规模化落地路径,将在与企业/个人业务的深度融合过程中起一场应用的“AI革命”,并带来从应用产品形态、开发模式到价值理念的一系列全新变化,而其实现大规模落地的发力点将集中在应用层... 详细信息

AIGC作为一条为用户、企业、社会带来切实价值的AI规模化落地路径,将在与企业/个人业务的深度融合过程中起一场应用的“AI革命”,并带来从应用产品形态、开发模式到价值理念的一系列全新变化,而其实现大规模落地的发力点将集中在应用层的创新层面。

关键词：产品形态深度融合应用层开发模式 AI 发力点发展趋势研究价值理念

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爆炸作用下建筑结构高效毁伤评估方法

爆炸与冲击 2024年

作者：吕晋贤吴昊卢永刚陈德 1.同济大学土木工程学院 2.中国工程物理研究院总体工程研究所同济大学土木工程学院中国工程物理研究院总体工程研究所

爆炸作用下建筑结构毁伤等级的高效预测有助于优化战前火力部署，评估战后毁伤效果，同时也可为重要建筑目标防护设计提供指导。然而，受限于建筑结构目标特性多样、体量庞大、内部系统庞杂以及验证困难等特点，尚缺乏高效的毁伤评估方... 详细信息

爆炸作用下建筑结构毁伤等级的高效预测有助于优化战前火力部署，评估战后毁伤效果，同时也可为重要建筑目标防护设计提供指导。然而，受限于建筑结构目标特性多样、体量庞大、内部系统庞杂以及验证困难等特点，尚缺乏高效的毁伤评估方法。借助高精度数值仿真分析，提出了综合考虑爆炸荷载、构件、房间和整体毁伤等级的建筑结构毁伤评估方法。首先，提出了爆炸作用下典型地面建筑，即含填充墙钢筋混凝土（RC）框架结构，损伤破坏和倒塌的高精度数值仿真分析方法，并得到RC结构爆炸试验和倒塌事故，以及砌体墙爆炸试验的充分验证。其次，开展了典型三层原型RC框架结构在不同爆炸当量（2.～2.0kg TNT）作用下的内爆炸数值仿真，定量分析了爆炸冲击波在建筑结构内部的传播、结构损伤破坏和墙体飞散等。进一步给出了爆炸作用下建筑结构的高效毁伤评估流程，即：基于镜像爆源结合非线性叠加原理确定内爆炸荷载；基于等效单自由度方法评估梁、板、柱及墙体构件的毁伤等级；引入构件重要性系数加权确定房间毁伤等级；考虑房间功能及位置重要性评估整体结构的毁伤等级。最后，基于上述爆炸工况，通过对比高精度数值仿真分析与毁伤评估方法的预测结果，表明：两者得到的典型RC框架结构的整体毁伤等级一致，即在2.kg、100kg和2.0kg TNT爆炸下分别呈现轻度、中度和重度毁伤，提出方法可缩短99%以上的计算耗时，兼具可靠性与时效性。

关键词：爆炸荷载建筑结构毁伤评估损伤破坏