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Thresholds of geographic environmental elements in sediment yield of drainage basins

science china Earth sciences 2005年第2期48卷 230-240页

作者： CHEN Hao, ZHOU Jinxing, CAI Qiangguo, LU Zhongchen & LI Zhongyan institute of Geographic sciences and Natural Resources Research, chinese academy of sciences, Beijing 100101, china institute of forestry science, chinese academy of forestry science, Beijing 100091, china Research Center for Eco-Environment sciences, chinese academy of sciences, Beijing 100085, china Computing institute of science and Engineering, North china Electric Power University, Beijing 102206, china institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences Beijing China institute of forestry science Chinese Academy of Forestry Science Beijing China Research Center for Eco-Environment sciences Chinese Academy of Sciences Beijing China Computing institute of science and Engineering North China Electric Power University Beijing China

Threshold of environmental elements in drainage basin sediment yield refers to, under effect of climate, underlying surface and human activity, a turning point of abrupt changes in drainage sediment yield related to environmental element characteristics. Previous studies on threshold of sediment yield of relevant drainage basins were mainly concentrated on impact of natural zones with a few researches on impact of other environmental elements. Particularly studies on compound environmental element threshold in drainage basin sediment yield remain blank today. Studies indicate that sediment yield in drainage basins is affected by compound interactions and complex actions. Based on single element analysis, the present paper gives quantitatively compound threshold of environmental elements affecting sediment yield of the drainage basin between Hekouzhen and Tongguan in the middle Yellow River by the method of multi-variant, polynomial formula regression analysis.

关键词： middle Yellow River, environmental element, sediment, sediment delivery mudule, threshold.

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中国政治经济学年度发展报告（2023）（下）

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政治经济学评论 2024年第3期 90+207-208页

作者： Center for Studies of Contemporary Political Economy,Research institute for 21st-Century Marxism,Nankai University·University of chinese academy of Social science Center for Teaching and Research on Capital,Renmin University of china National institute of Socialist Political Economy with chinese Characteristics,Renmin University of china 南开大学·中国社会科学院大学21世纪马克思主义研究院当代政治经济学研究中心中国人民大学《资本论》教学与研究中心中国人民大学全国中国特色社会主义政治经济学研究中心

编者按2023年，高质量发展扎实推进，新质生产力加快形成，我国经济总体回升向好，圆满实现发展主要预期目标。为针对性地破解经济恢复发展中的难题，聚焦推进中国式现代化进程中的重点、难点问题，中国政治经济学界开展系统深入研究，...

编者按2023年，高质量发展扎实推进，新质生产力加快形成，我国经济总体回升向好，圆满实现发展主要预期目标。为针对性地破解经济恢复发展中的难题，聚焦推进中国式现代化进程中的重点、难点问题，中国政治经济学界开展系统深入研究，取得系列代表性成果。为准确刻画学界研究进展和轨迹，推动中国经济学理论体系的构建和完善，本刊精选议题如期奉上《中国政治经济学年度发展报告（2023）》。自2010年起，本刊连续十四年发布《中国政治经济学年度发展报告》，“年度发展报告”专栏已成为本刊标志性特色栏目。2023年报告聚焦12个专题，分为（上）（下）两篇，其中专题1—6于报告（上）篇刊登，专题7—12由报告（下）篇刊登。2023年报告（下）选题如下：

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咖啡因的科学共识

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中国食品学报 2024年第6期24卷 498-504页

作者：中国食品科学技术学会北京100048

咖啡因是一种常见于咖啡、茶叶和可可等植物中的天然活性成分,作为功能添加成分已在国际食品领域广泛应用多年,适量摄入有助于健康人群提高注意力,促进运动能力,缓解疲劳。国内外相关食品安全监管机构一致认为,咖啡因虽在日常饮食中的... 详细信息

咖啡因是一种常见于咖啡、茶叶和可可等植物中的天然活性成分,作为功能添加成分已在国际食品领域广泛应用多年,适量摄入有助于健康人群提高注意力,促进运动能力,缓解疲劳。国内外相关食品安全监管机构一致认为,咖啡因虽在日常饮食中的摄入是安全的,但需关注个体差异、摄入量以及频率。许多国家和地区已对咖啡因在食品中的应用制定了严格的应用限量和标识规定。为进一步提升大众对咖啡因的科学认知,消除对咖啡因的偏见,推动咖啡因在相关食品产业的合理应用,中国食品科学技术学会组织食品科学、公共卫生、食品安全与食品营养等领域专家与相关产业界代表,通过现场咨询、文献检索、专题研讨等形式和方法,经广泛讨论形成咖啡因的科学共识,以推动咖啡因在我国的规范使用。

关键词：咖啡因健康益处摄入量应用管理

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The global climate change and forest prediction in china

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Journal of Environmental sciences 1994年第3期6卷 310-321页

作者： Jiang Youxuforestry institute, chinese academy of forestry, Beijing 100091, china

The climate change prediction in china based on OCU model as well as summary ana-lyses of GFDL, GISS, NCAR, OCU and UKMO models are used for discussing the approaches topredict the response of the forest in china under double concentration of atmospheric carbondioxide after about 2020. The growth, production and distribution boundary of chinese fir(Cunninghamia lanceolata), the tree composition and their growth in cold temperete Daxingan Moun-tain region, and potential forest zones in china are discussed in this paper as example.

关键词： global climate change forest in china prediction.

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A STUDY ON ENERGY OF ARTIFICIAL DAHURIAN LARCH COMMUNITY

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Journal of Northeast forestry University 1992年第2期3卷 101-108页

作者： Liu ShirongThe Research institute of forestry,chinese academy of forestry The Research institute of forestry Chinese Academy of Forestry China

By means of calorimctry measurement, the caloric values of various components, the standing crop of energy, net energy production and energy conversing efficiency of an artificial dahurian larch community at Laoshan Plantation Experimental Station of Maoer Shan Forest Farm in the eastern part of northeast china were determined and studied in the present paper. The result of the experiment were as follows: (1) caloric value varied with plant species and plant organs, in general, the order of caloric value was tree, shrub and herb, and for different organs, was leaf, branch, trunk (stem), bark and root. (2) The standing crop of energy of larch community and tree layer were 269.719 × 1010J/ha. and 264.440×10l0J/ha. respectively. There existed different distributions of energy in various components and different layers. (3) Net energy production of larch community and its tree layer were 264.346 × 108J/ha.a and 243.678 × 108J/ ha.a respectively. To the photosythctical active radiation on the stand, its energy conversing efficiency was 2.2990%. Compared with other common forest communities in nature, artificial larch community has a relative larger energy production and higher conversing efficiency.

关键词： Energy Larch Community

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Digital forestry research in china

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science china(Technological sciences) 2006年第Z1期49卷 1-8页

作者： TANG Shouzheng, TANG Una, Guofan Shao & DAI Limin Research institute of Resource Information Techniques, chinese academy of forestry, Beijing 100091, china institute of Applied Ecology, chinese academy of sciences, Shenyang 110016, china Departmet of forestry and Natural Resources, Purdue University, West Lafayette, IN 47907, USA Graduate University, chinese academy of sciences, Beijing 100101, china Research institute of Resource Information Techniques Chinese Academy of Forestry Beijing China institute of Applied Ecology Chinese Academy of Sciences Shenyang China Graduate University Chinese Academy of Sciences Beijing China Department of forestry and Natural Resources Purdue University West Lafayette USA

Digital forestry as a concept was developed after the Digital Earth program. The chinese scientists were not only among the pioneers who first proposed the concept of Digital forestry, but also contributed a lot to the development of Digital forestry. Digital forestry is a digital framework to maintain forest planting, management, using, and protect. The synergetic use of computationally-intensive quantitative methods together with information technologies is the most important foundation for the development of Digital forestry. Under this situation, the experience of Digital forestry development in china is relatively rich. A number of academicians, scholars, and professional administrators were involved in discussing the Digital forestry Construction Scheme. The Project of Digital forestry Practicability approved by the State forestry Administration is a major instance in developing Digital forestry standard and key techniques. By introducing a case study of Digital forestry, this paper reviews the concept of Digital forestry, the way turning traditional forestry into Digital forestry, and the future development of Digital forestry.

关键词： Digital Forest, Digital Earth, Digital forestry standard, Digital forestry techniques.

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THE CULTURE HISTORY AND BREEDING STRATEGY OF POPLAR IN ITALY

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Journal of Northeast forestry University 1992年第2期3卷 95-100页

作者： Xu Hongyuan Research institute of forestry ,chinese academy of forestry Research institute of forestry Chinese Academy of Forestry China

INTRODUCTION In Italy,they have done many bcnefi-cial works in the high yield plantation--the culture and the breeding of ***,in our country,introduced manygood clones such as I—214,I—72 and I—*** the clones were t... 详细信息

关键词： THE CULTURE HISTORY AND BREEDING STRATEGY OF POPLAR IN ITALY

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Analysis of forest backscattering characteristics based on polarization coherence tomography

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science china(Technological sciences) 2010年第S1期53卷 166-175页

作者： LUO HuanMin 1,LI XiaoWen 1,2,CHEN ErXue 3,CHENG Jian 4 & CAO ChunXiang 21 institute of Geo-Spatial Information science and Technology,University of Electronic science and Technology of china,Chengdu 610054,china 2 State Key Laboratory of Remote Sensing science,Jointly Sponsored by the institute of Remote Sensing Applications of chinese academy of sciences and Beijing Normal University,Beijing 100101,china 3institute of Forest Resources Information Technique of chinese academy of forestry,Beijing 100091,china 4 School of Electronic Engineering,University of Electronic science and Technology of china,Chengdu 610054,china institute of Geo-Spatial Information science and Technology University of Electronic Science and Technology of China Chengdu China State Key Laboratory of Remote Sensing science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China institute of Forest Resources Information Technique of chinese academy of forestry Beijing China School of Electronic Engineering University of Electronic Science and Technology of China Chengdu China

It is difficult to make an inventory of vertical profiles of forest structure parameters in field ***,analysis and understanding of forest backscattering characteristics contribute to estimation and detection of forest vertical structure because of the close relationships between backscattering characteristics and structure *** vertical structure function in the complex interferometric coherence definition,which represents the vertical variation of microwave scattering with the penetration depth at a point in the 2-D radar image and can be used to analyze the forest backscattering characteristics,can be reconstructed from polarization coherence tomography(PCT).Based on PCT,the paper analyzes the forest backscattering characteristics and explores the inherent relationship between the result of PCT and the forest structure parameters from numerical simulation of Random Volume over Ground model(RVoG),Polarimetric SAR interferometry(PolInSAR)simulation of forest scene and PolInSAR data at L-band of the test site ***,the effects of the extinction coefficient and surface-to-volume scattering ratio in RVoG model on vertical backscattering characteristics are analyzed by means of numerical ***,by applying PCT to L-band POLInSAR simulations of forest scene,different variations of vertical backscattering due to different extinction coefficients and the ratios of surface-to-volume scattering resulting from different polarizations,forest types and densities are displayed and *** a concept of relative average backscattering intensity is presented,and the factors which affect its vertical distribution are also *** results show that there is high sensitivity of the vertical distribution of forest relative average backscattering intensity to the polarization,forest type and ***,based on repeat pass DLR E-SAR L-band airborne POLInSAR data,the capability of PCT technology for detection

关键词： backscattering characteristic POLInSAR PCT vertical structure function

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BOUNDARY FEEDBACK STABILIZATION OF NONUNIFORM TIMOSHENKO BEAM WITH A TIPLOAD

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chinese Annals of Mathematics,Series B 2001年第4期22卷 485-494页

作者： YAN QINGXU, FENG DEXING institute of Systems science, academy of Mathematics and Systems science, chinese academy of sciences, Beijing 100080, china. institute of Systems science, academy of Mathematics and Systems science, chinese academy of sciences, Be institute of Systems science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China

The boundary stabilization problem of a Timoshenko beam attached with a mass at one end is studied. First, with linear boundary force feedback and moment control simultaneously at the end attached with the load, the energy corresponding to the closed loop system is proven to be exponentially convergent to zero as time t →∞. Then, some counterexamples are given to show that, in other casest the corresponding closed loop system is, in general, not stable asymtotically, let alone exponentially.

关键词： Timoshenko beam Boundary feedback control C0 semigroups Exponential stability Multiplier method

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PROBABILISTIC NUMERICAL APPROACH FOR PDE AND ITS APPLICATION IN THE VALUATION OF EUROPEAN OPTIONS

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Journal of Computational Mathematics 2001年第6期19卷 591-600页

作者： Dong-sheng Wu (institute of Systems science, academy of Mathematics and Systems sciences, chinese academy of sciences, Beijing 100080, china ) 中科院系统科学所北京 100080

Presents a probabilistic numerical approach for a class of probabilistic differential equation. Application of the Brownian motion and Monte-Carlo method; Application in the valuation of European Options.

关键词： Brownian motion probabilistic numerical solution European Options

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