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CREG held an academic seminar on the development and utilization of rare earth mineral resources
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《China Rare Earth Information》 2023年第4期24-24,共1页
China Rare Earth Group(CREG)held an academic seminar on the development and utilization of rare earth mineral resources in Ganzhou recently.Global new pattern of rare earth resources development and the current situat... China Rare Earth Group(CREG)held an academic seminar on the development and utilization of rare earth mineral resources in Ganzhou recently.Global new pattern of rare earth resources development and the current situation of technology development were discussed,and the strategic opportunities and challenges faced by China were analyzed. 展开更多
关键词 earth resources ACADEMIC
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Interrelationships between Length of the Day, Moon Distance, Phanerozoic Geodynamic Cycles, Tidal Dissipation and Earth’s Core: Review and Analysis
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作者 Heinz-Jürgen Brink 《International Journal of Geosciences》 CAS 2024年第5期396-415,共20页
The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around... The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around the rotation axis of the spinning Earth during the growth of the core the rotation should have been accelerated. Controversially the tidal dissipation by the Moon, which is mainly dependent on the availability of open shallow seas and the kind of Moon escape from a nearby position, acts towards a deceleration of the rotating Earth. Measurements of LOD for Phanerozoic and Precambrian times open ways to solve questions concerning the geodynamical history of the Earth. These measurements encompass investigations of growth patterns in fossils and depositional patterns in sediments (Cyclostratigraphy, Tidalites, Stromatolites, Rhythmites). These patterns contain information on the LOD and on the changing distance between Earth and Moon and can be used as well for a discussion about the growth of the Earth’s core. By updating an older paper with its simple approach as well as incorporating newly published results provided by the geoscientific community, a moderate to fast growth of the core in a hot early Earth will be favored controversially to the assumption of a delayed development of the core in an originally cold Earth. Core development with acceleration of Earth’s rotation and the contemporaneous slowing down due to tidal dissipation during the filling of the ocean may significantly interrelate. 展开更多
关键词 Length of the Day Moon Distance Phanerozoic Geodynamic Cycles Tidal Dissipation earths Core
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The Dilemma and Way Out of China’s Participation in the Development of Marine Genetic Resources in ABNJ from the Perspective of BBNJ
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作者 Qu Yanan Zhang Zixuan 《Journal of Shipping and Ocean Engineering》 2023年第1期1-9,共9页
The fifth intergovernmental negotiations on marine BBNJ(Biodiversity beyond Areas of National Jurisdiction)concluded in August 2022,in which there are still major differences regarding access to marine genetic resourc... The fifth intergovernmental negotiations on marine BBNJ(Biodiversity beyond Areas of National Jurisdiction)concluded in August 2022,in which there are still major differences regarding access to marine genetic resources,management,and technology transfer.China’s participation in the development of marine genetic resources in ABNJ(areas beyond national jurisdiction)has many dilemmas,which are linked to the difficulties faced in advancing the BBNJ negotiations.The following countermeasures are proposed at the institutional and practical levels respectively:clarifying the legal attributes and applicability of the principles of marine genetic resources;establishing mechanisms for access,management,environmental impact assessment and benefit sharing of marine genetic resources;and using the“Blue Partnership”to build a governance mechanism for marine genetic resources to achieve mutual benefits. 展开更多
关键词 Marine genetic resources ABNJ BBNJ perspective China’s response
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Earth Resources Exploitation and Sustainable Development: Geological and Engineering Perspectives
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作者 C. C. Iwuji O. C. Okeke +2 位作者 B. C. Ezenwoke C. C. Amadi H. Nwachukwu 《Engineering(科研)》 2016年第1期21-33,共13页
Earth resources are the essential basis for an economy of a country and well-being of her citizens. Their exploitation is a key factor in economic growth and development of the nation, but one that can have serious ne... Earth resources are the essential basis for an economy of a country and well-being of her citizens. Their exploitation is a key factor in economic growth and development of the nation, but one that can have serious negative environmental and socio-economic impacts. Therefore it is important to understand their origin/occurrence and exploitation in terms of environmental sustainability. The human society has profited from exploitation of earth resources, precisely when energy use became much more efficient during the industrial era. Some of these earth resources (renewable and non-renewable) are oil and gas, coal, water, metal ore, wind, air etc. and their methods of exploitation are surface and subsurface mining methods [1]. Thus the geological perspectives of earth resources refer to origin and occurrence of these earth resources while the engineering perspectives refer to the processes involved in the extraction (mining), processing and utilization of the resources. To fulfill the requirement of sustainable development, the efficiency with which resources are utilized has to be improved. The main concerns associated with earth resources, therefore, are generally the costs and environmental impacts of extracting, transporting, and refining them. The economics of earth resources deals with the supply, demand and allocation of the resources. 展开更多
关键词 earth resources EXPLOITATION sustainable Development Geological and Engineering Perspectives
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Develop hydroenergy resources and protect earth environment
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作者 Lu Youmei 《Engineering Sciences》 EI 2009年第2期32-34,63,共4页
Energy is a driving force behind the progress of human civilization. Mainly depend on the current human society of non-renewable fossil energy sources, such as coal and oil, its increasing demand. Gradually reduce the... Energy is a driving force behind the progress of human civilization. Mainly depend on the current human society of non-renewable fossil energy sources, such as coal and oil, its increasing demand. Gradually reduce the reserves, the contradiction between supply and demand becoming increasingly prominent. With the process of human history has moved forward with the depletion of fossil energy will eventually be unable to sustainable use. The total hydropower resources are limited, but it is renewable, clean energy, its energy is infinite. Therefore, the full use of limited water resources and slow down the depletion of fossil energy process, is to improve and protect the earth’s ecology and environment, one of the most realistic measures. 展开更多
关键词 地球环境 水能资源 保护 开发 化石能源 矿物能源 人类文明 人类社会
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甘肃积石山 M_(s)6.2级地震的震害特征与启示 被引量:2
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作者 王丽丽 王兰民 +5 位作者 卢育霞 许世阳 夏晓雨 盖海龙 池佩红 郭梅 《世界地震工程》 北大核心 2024年第1期58-71,共14页
2023年12月18日,甘肃省临夏回族自治州积石山保安族东乡族撒拉族自治县(35.70°N,102.79°E)发生了6.2级地震,震中烈度为VIII度。地震发生后,通过实地烈度评估与科学考察,对震区VI~VIII度区不同建(构)筑物与生命线工程的震害特... 2023年12月18日,甘肃省临夏回族自治州积石山保安族东乡族撒拉族自治县(35.70°N,102.79°E)发生了6.2级地震,震中烈度为VIII度。地震发生后,通过实地烈度评估与科学考察,对震区VI~VIII度区不同建(构)筑物与生命线工程的震害特点进行了统计分析;从抗震设计与施工管理、场地放大效应与地震次生灾害对建筑结构抗震性能的影响等角度,提出了此次地震的震害启示。结果表明:1)严重破坏和毁坏的建筑结构主要集中在老旧的土木结构、砖木结构和无设防或设防不规范的砖混结构。2)造成建筑结构破坏的主要原因是少量自建房抗震设计和施工的不规范、场地放大效应和地震次生灾害。3)优化和改良生土砌筑材料,改进纵横墙间的拉结措施,强化结构整体性是提高土木结构抗震的有效方法;普及“上下圈梁与构造柱”等基本抗震设防措施,规范水泥砂浆强度,提升农村工匠的施工水平,可有效提高砌体结构的整体性,避免房屋出现整体性垮塌;室内洗手间的墙体应该与房顶、纵横墙间建立有效联接,提高结构的抗震性能。4)孤突斜坡、河流高阶地与岸边为抗震不利地带。当建造用地极为匮乏,不得不选址在这些场地之上时,应该综合考虑场地的地形地貌特征、岩土体物理力学特性、水文地质条件、抗震设防目标、建筑结构类型等影响因素,做好地震灾害风险评估,根据评估结果进行科学设防。灾后重建过程中,应由政府统一规划选址、统一设计,规范施工。 展开更多
关键词 积石山6.2级地震 震害调查 场地放大效应 黄土液化流滑 震害特征
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中强地震发震构造标志浅析——以2023年积石山M_(S)6.2地震为例
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作者 张军龙 徐岳仁 +1 位作者 李文巧 陈峰 《地震》 CSCD 北大核心 2024年第1期226-234,共9页
地震地表破裂是地震发生的重要特征,是研究地震动力学、构造变形的重要手段。一般认为,M6 3/4以上的地震才会形成地表破裂。但近年来,也有M6.0左右的地震发生了地表破裂。本文旨在探讨中强地震地表破裂的识别方法。中强地震发震构造的... 地震地表破裂是地震发生的重要特征,是研究地震动力学、构造变形的重要手段。一般认为,M6 3/4以上的地震才会形成地表破裂。但近年来,也有M6.0左右的地震发生了地表破裂。本文旨在探讨中强地震地表破裂的识别方法。中强地震发震构造的识别具有一定的挑战性,主要表现在以下几个方面:(1)中强地震地表破裂的规模(位错量、宽度、长度和深度)较小,容易被黄土层厚覆盖,掩盖地表破裂的痕迹,不易识别;(2)非构造成因裂缝干扰,使得难以区分构造成因地表破裂。本文以2023年积石山M_(S)6.2地震为例,对中强地震构造成因破裂的识别标志进行了初步分析,提出了以下识别标志:(1)地表破裂几何展布和剖面形态,地震伴生的次生灾害(滑坡、崩塌、砂土液化等)的线性分布为识别发震构造提供参考和线索;(2)地表破裂沿破裂走向呈现稳定地穿越不同地貌单元,至少穿越一条沟谷等低凹地貌;(3)地表破裂在地质剖面上表现出稳定的产状;(4)地表破裂伴生构造形态,地表沿破裂发育雁列式褶皱(挤压鼓包)与张裂缝交替出现的现象。本文提出的识别标志为中强地震发震构造的识别提供了新的思路。 展开更多
关键词 青藏高原 拉脊山断裂带 2023年积石山M_(s)6.2地震 发震构造 地震地表破裂
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Quality of life, work productivity impairment and healthcare resources in inflammatory bowel diseases in Brazil 被引量:2
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作者 Rogerio Serafim Parra Julio MF Chebli +27 位作者 Heda MBS Amarante Cristina Flores Jose ML Parente Odery Ramos Milene Fernandes Jose JR Rocha Marley R Feitosa Omar Feres Antonio S Scotton Rodrigo B Nones Murilo M Lima Cyrla Zaltman Carolina D Goncalves Isabella M Guimaraes Genoile O Santana Ligia Y Sassaki Rogerio S Hossne Mauro Bafutto Roberto LK Junior Mikaell AG Faria Sender J Miszputen Tarcia NF Gomes Wilson R Catapani Anderson A Faria Stella CS Souza Rosana F Caratin Juliana T Senra Maria LA Ferrari 《World Journal of Gastroenterology》 SCIE CAS 2019年第38期5862-5882,共21页
BACKGROUND Inflammatory bowel diseases(IBD)have been associated with a low quality of life(QoL)and a negative impact on work productivity compared to the general population.Information about disease control,patient-re... BACKGROUND Inflammatory bowel diseases(IBD)have been associated with a low quality of life(QoL)and a negative impact on work productivity compared to the general population.Information about disease control,patient-reported outcomes(PROs),treatment patterns and use of healthcare resources is relevant to optimizing IBD management.AIM To describe QoL and work productivity and activity impairment(WPAI),treatment patterns and use of healthcare resources among IBD patients in Brazil.METHODS A multicenter cross-sectional study included adult outpatients who were previously diagnosed with moderate to severe Crohn’s disease(CD)or ulcerative colitis(UC).At enrolment,active CD and UC were defined as having a Harvey Bradshaw Index≥8 or a CD Activity Index≥220 or calprotectin>200μg/g or previous colonoscopy results suggestive of inadequate control(per investigator criteria)and a 9-point partial Mayo score≥5,respectively.The PRO assessment included the QoL questionnaires SF-36 and EQ-5D-5L,the Inflammatory Bowel Disease Questionnaire(IBDQ),and the WPAI questionnaire.Information about healthcare resources and treatment during the previous 3 years was collected from medical records.Chi-square,Fisher’s exact and Student’s t-/Mann-Whitney U tests were used to compare PROs,treatment patterns and the use of healthcare resources by disease activity(α=0.05).RESULTS Of the 407 patients in this study(CD/UC:64.9%/35.1%,mean age 42.9/45.9 years,54.2%/56.6%female,38.3%/37.1%employed),44.7%/25.2%presented moderate-to-severe CD/UC activity,respectively,at baseline.Expressed in median values for CD/UC,respectively,the SF-36 physical component was 46.6/44.7 and the mental component was 45.2/44.2,the EQ-visual analog scale score was 80.0/70.0,and the IBDQ overall score was 164.0/165.0.Moderate to severe activity,female gender,being unemployed,a lower educational level and lower income were associated with lower QoL(P<0.05).Median work productivity impairment was 20%and 5%for CD and UC patients,respectively,and activity impairment was 30%,the latter being higher among patients with moderate to severe disease activity compared to patients with mild or no disease activity(75.0%vs 10.0%,P<0.001).For CD/UC patients,respectively,25.4%/2.8%had at least one surgery,38.3%/19.6%were hospitalized,and 70.7%/77.6%changed IBD treatment at least once during the last 3 years.The most common treatments at baseline were biologics(75.3%)and immunosuppressants(70.9%)for CD patients and 5-ASA compounds(77.5%)for UC patients.CONCLUSION Moderate to severe IBD activity,especially among CD patients,is associated with a substantial impact on QoL,work productivity impairment and an increased number of IBD surgeries and hospitalizations in Brazil. 展开更多
关键词 Inflammatory BOWEL DIsEAsE Crohn’s DIsEAsE ULCERATIVE COLITIs Quality of life Healthcare resources
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Resource allocation for uplink grant-free access in beam-hopping based LEO satellite systems
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作者 张梦莹 YANG Xiumei BU Zhiyong 《High Technology Letters》 EI CAS 2023年第2期140-147,共8页
The low earth orbit(LEO) satellite system provides a promising solution for the global coverage of Internet of Things(IoT) services.Confronted with the sporadic uplink transmission from massive IoT terminals, this wor... The low earth orbit(LEO) satellite system provides a promising solution for the global coverage of Internet of Things(IoT) services.Confronted with the sporadic uplink transmission from massive IoT terminals, this work investigates the grant-free access scheme and resource allocation algorithm for the beam-hopping(BH) based LEO satellite systems.To improve the packet success rate, the time slots are pre-allocated to each cell according to the number of terrestrial terminals and the probability of packet arrival.When the packets arrive, the terrestrial terminals perform contention-free or contention-based grant-free access with packet repetition in the time slots allocated to their cells.The analytical expression of the packet collision probability for the grant-free access scheme is derived to provide reference for the resource allocation.To reduce the computational complexity, a heuristic resource allocation algorithm is proposed to minimize the maximum cell packet collision probability in the system.Simulation results show that the proposed resource allocation scheme achieves lower packet collision probability and higher resource utilization ratio when compared with the uniform resource allocation scheme. 展开更多
关键词 low earth orbit(LEO)satellite system grant-free access beam-hopping(BH) resource allocation collision
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RELATIVE SEA LEVEL RISE AND ITS EFFECTS ON ENVIRONMENT AND RESOURCES IN CHINAS COASTAL AREAS 被引量:2
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作者 杨桂山 《Chinese Geographical Science》 SCIE CSCD 1995年第2期104-115,共12页
Due to global climate warming and natural and man-made land subsidence etc., relative sea level rise in the coastal plains of China will exceed 2-3 times over the golbal mean value during the first half part of the 21... Due to global climate warming and natural and man-made land subsidence etc., relative sea level rise in the coastal plains of China will exceed 2-3 times over the golbal mean value during the first half part of the 21st century. It will result in a series of adverse impacts on evolution of natural environment and socioeconomic development of the coastal area. This paper analyses environmental and resource effects induced by relative sea level rise in China's coastal areas on the basis of rough estimate of future relative sea level rise. These effects include inundating tidal flat and wetlands and increase in inundated risk of coastal habitable land,exacerbating storm surge. coastal erosion, flooding and salt water intrusion hazards.as well as endangering land. water. tourism and living resources and their utilization. 展开更多
关键词 China’s COAsTAL areas. RELATIVE sEA LEVEL RIsE environmental effect resource effect
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O、S、Ce含量对U71MnG钢中Ce_(2)O_(3)和Ce_(2)O_(2)S夹杂物的影响
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作者 王敏 刘香军 +1 位作者 杨昌桥 杨吉春 《稀有金属与硬质合金》 CAS CSCD 北大核心 2024年第2期45-49,共5页
我国稀土钢未实现大规模的生产,其主要原因是对稀土与钢中O、S等杂质元素的相互作用规律认识不足。考虑到Ce、O、S含量对钢中稀土夹杂物的影响缺少定量分析,使用FactSage 7.1软件计算U71MnG钢中不同含量O、S、Ce之间的相互作用关系及其... 我国稀土钢未实现大规模的生产,其主要原因是对稀土与钢中O、S等杂质元素的相互作用规律认识不足。考虑到Ce、O、S含量对钢中稀土夹杂物的影响缺少定量分析,使用FactSage 7.1软件计算U71MnG钢中不同含量O、S、Ce之间的相互作用关系及其对Ce_(2)O_(2)S、Ce_(2)O_(3)夹杂物析出量的影响。热力学计算结果表明,在U71MnG钢的成分体系下,随着Ce含量的增多,Ce_(2)O_(3)的析出量呈先增多后减少的趋势,m_(O)/m_(Ce)约为1/7.4时,Ce_(2)O_(3)的析出量最大;Ce_(2)O_(2)S的生成需要O、S、Ce共同作用,m_(O+S)/m_(Ce)约为1/3.7时,Ce_(2)O_(2)S析出量最大。试验钢夹杂物的SEM图像以及夹杂物颗粒数量统计结果显示,Ce含量为0.024%的试验钢中Ce_(2)O_(3)、Ce_(2)O_(2)S的个数大于Ce含量为0.016%的试验钢,钢中夹杂物析出规律与热力学计算结果一致。 展开更多
关键词 稀土夹杂物 热力学 Ce_(2)O_(2)s Ce_(2)O_(3)
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Possible Evolutionary Models in the Initially Hydride Earth Theory
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作者 Kudryavtsev Pavel 《International Journal of Geosciences》 CAS 2023年第5期377-426,共50页
A modern view of the properties of chemical elements has confirmed the theory of the hot origin of the Earth. The next step in developing this theory was the hypothesis of the initial hydride Earth. In this work, we a... A modern view of the properties of chemical elements has confirmed the theory of the hot origin of the Earth. The next step in developing this theory was the hypothesis of the initial hydride Earth. In this work, we attempted to find additional evidence for this hypothesis and show additional effects that flow from it. The effect of the physical properties of atoms and ions on their behavior during the formation of the Earth was studied. The maximum contribution to the distribution of elements was made by those elements whose content in the original protoplanets of the disk was the maximum. Correlation dependence is obtained, which allows one to calculate the distribution of elements in the protoplanetary disk. It was shown that hydrogen was the main element in the proto substance located in the zone of the Earth’s formation. In this case, various chemical compounds formed, most represented by hydrogen compounds—hydrides. Since the pressure inside the Earth is 375 GPa, this factor forces the chemical compounds to adopt stoichiometry and structure that would not be available in atmospheric conditions. It is shown that many chemical elements at high pressure in a hydrogen medium form simple hydrides and super hydrides—polyhydrides with high hydrogen content. Pressure leads to a higher density of matter inside the planet. Given the possibility of forming polyhydrides, there is the possibility of binding the initially available hydrogen in an amount that can reach 49.3 mole%. Young Earth could contain about 10.7 mass% of hydrogen in hydrides, polyhydrides, and adsorbed form is almost twice higher than previous estimates. This fact additionally confirms the theory of the original hydride Earth. In hydrides, the occurrence of the phenomenon of superconductivity was discovered. Polyhydrides were shown as potential superconductors with a high critical temperature above 200 K. We, based on these data, hypothesized the presence of superconducting properties in the Earth’s core, which explains the presence of a magnetic field in the Earth, as well as the unevenness and instability of this field and the possibility of migration of the Earth’s poles. The fact that the Earth has a hydroid core causes its change in time due to the instability of hydrides. Arranged several possible models of the destruction of the Earth’s core. The calculations showed that both models give close results. These results give predictions that can be measured. The proposed models also made it possible to estimate the initial size of the Earth. Possible ways of further testing the hypothesis of the initial hydride Earth is shown. 展开更多
关键词 Theory of the Hot Origin of the earth Magnetic separation of Elements Atom Ionization Energy Hydrides Polyhydrides earth Expansion superconductivity of the earths Core
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Dominant woody plant species recognition with a hierarchical model based on multimodal geospatial data for subtropical forests
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作者 Xin Chen Yujun Sun 《Journal of Forestry Research》 SCIE EI CAS CSCD 2024年第3期111-130,共20页
Since the launch of the Google Earth Engine(GEE)cloud platform in 2010,it has been widely used,leading to a wealth of valuable information.However,the potential of GEE for forest resource management has not been fully... Since the launch of the Google Earth Engine(GEE)cloud platform in 2010,it has been widely used,leading to a wealth of valuable information.However,the potential of GEE for forest resource management has not been fully exploited.To extract dominant woody plant species,GEE combined Sen-tinel-1(S1)and Sentinel-2(S2)data with the addition of the National Forest Resources Inventory(NFRI)and topographic data,resulting in a 10 m resolution multimodal geospatial dataset for subtropical forests in southeast China.Spectral and texture features,red-edge bands,and vegetation indices of S1 and S2 data were computed.A hierarchical model obtained information on forest distribution and area and the dominant woody plant species.The results suggest that combining data sources from the S1 winter and S2 yearly ranges enhances accuracy in forest distribution and area extraction compared to using either data source independently.Similarly,for dominant woody species recognition,using S1 winter and S2 data across all four seasons was accurate.Including terrain factors and removing spatial correlation from NFRI sample points further improved the recognition accuracy.The optimal forest extraction achieved an overall accuracy(OA)of 97.4%and a maplevel image classification efficacy(MICE)of 96.7%.OA and MICE were 83.6%and 80.7%for dominant species extraction,respectively.The high accuracy and efficacy values indicate that the hierarchical recognition model based on multimodal remote sensing data performed extremely well for extracting information about dominant woody plant species.Visualizing the results using the GEE application allows for an intuitive display of forest and species distribution,offering significant convenience for forest resource monitoring. 展开更多
关键词 Google earth Engine sENTINEL Forest resource inventory data Dominant woody plant species sUBTROPICs Model performance
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Research on the Development of Kindergarten-Based Curriculum with Tongyu New Year’s Paintings as Curriculum Resource
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作者 He Hao 《Journal of Contemporary Educational Research》 2023年第12期169-174,共6页
With the rapid development of modern society,the protection and inheritance of traditional culture are becoming increasingly important.As a part of Chinese traditional culture,Tongyu New Year’s Paintings,with their u... With the rapid development of modern society,the protection and inheritance of traditional culture are becoming increasingly important.As a part of Chinese traditional culture,Tongyu New Year’s Paintings,with their unique artistic style and rich cultural connotation,have become an excellent resource for exploring the beauty of tradition and inspiring creativity.Based on this,LH Kindergarten in Baicheng City,Jilin Province,has utilized Tongyu New Year’s Paintings as a curriculum resource to develop a school-based curriculum,“The Beauty of Tongyu New Year’s Paintings:Artistic Exploration for Teachers and Children.”Through diversified learning styles,teachers and children will learn about the history of New Year’s paintings,incorporate certain features of the paintings into their art activities,and cultivate creativity and the spirit of teamwork,so as to pass on the precious essence of traditional culture to children and carry forward the spirit of teamwork in their hearts.This program will lead children to experience the treasures of traditional culture and the rich connotations behind Chinese New Year’s paintings,laying a solid foundation for their growth and lifelong learning. 展开更多
关键词 Tongyu New Year’s Paintings Curriculum resources Kindergarten-based curriculum
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Remarks about External Forces Acting on Earth’s Rotation Axis
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作者 Monica Zoe Ciobanu 《World Journal of Mechanics》 2023年第2期73-77,共5页
It is well known that a variation in the direction of Earth’s rotation axis is a real astronomical phenomenon, named nutation. It is interesting if a variation of this axis can take place only in intensity, in the si... It is well known that a variation in the direction of Earth’s rotation axis is a real astronomical phenomenon, named nutation. It is interesting if a variation of this axis can take place only in intensity, in the simplest theoretical case of only two rigid body dynamics. This paper presents two positions of the Moon during its monthly orbit, where a sudden variation of Earth’s rotation axis in intensity can take place. The duration of this phenomenon is limited in time, maybe an instant or a day, and then a vortex can appear. 展开更多
关键词 NUTATION Variation in Intensity of earths Rotation Axis Chandler’s Wobble
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Fluctuating resources,disturbance and plant strategies:diverse mechanisms underlying plant invasions 被引量:1
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作者 Ian J RADFORD 《Journal of Arid Land》 SCIE CSCD 2013年第3期284-297,共14页
This paper examines the hypothesis that non-native plant invasions are related to fluctuating resource availability as proposed by Davis et al. (2000). I measured relative functional responses of both invasive and n... This paper examines the hypothesis that non-native plant invasions are related to fluctuating resource availability as proposed by Davis et al. (2000). I measured relative functional responses of both invasive and native plants to changed resource availability due to nutrient enrichment and rainfall, and to increased disturbance. Data are presented from studies in two contrasting ecosystems. First is a series of glasshouse and field experiments on the invader Hieracium lepidulum and associated invasive and native species in subalpine temperate New Zealand. Second is a field study of invasive and native plant responses to altered disturbance regimes and rainfall from tropical savannas of north eastern Australia. Invaders responded differently from native species to changes in resource availability in both subalpine and tropical studies. However, invaders differed among themselves showing that different species exploit different functional niches to invade their respective habitats. These findings contribute to the contention that the fluctuating resource hypothesis does not provide a universal explanation for plant invasions. The diverse functional responses to increased resource availability among invaders in this and previous studies suggest that the cause of invasion depends on unique combinations of habitat and functional attributes of invaders and native assemblages. Such findings imply that universal predictions of what will happen under climate change scenarios across the globe will be difficult to make. 展开更多
关键词 plant invasion plant strategies C-s-R triangle fluctuating resources DIsTURBANCE
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Analysis on the deployment of mining research supported by the grant program of Deep Resources Exploration and Mining
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作者 FAN Jun ZHANG Jialin +3 位作者 QIN Yuan WANG Hao GAO Yanan PEI Yongzhi 《煤田地质与勘探》 CAS CSCD 北大核心 2021年第3期1-7,共7页
The Deep Resources Exploration and Mining(DREAM)grant program,within the framework of The National Key Research and Development Program grants,is a pillar to implement China’s science and technology strategy in the a... The Deep Resources Exploration and Mining(DREAM)grant program,within the framework of The National Key Research and Development Program grants,is a pillar to implement China’s science and technology strategy in the area of deep resources exploitation.To tackle the insufficient of theories and technologies for the 1000-meter-deep mining,a section of mining,covering the research of basic theories,general technologies and application demonstration,was arranged in the layout of DREAM under the principle of"whole chain design,integrated implementation".In the aspect of basic research,DREAM mainly focused on the deep rock mechanics and mining theory,such as the in-situ mechanical behavior of deep rock,deep high stress induction and energy regulation theory.For the general and key technologies,DREAM supported the research on the mine construction and hoisting,excavation,rock breaking,mining methods and mining safety according to the characteristics of coal and metal mines.For the demonstration application,taking green,safe and efficient as the starting point,DREAM aimed at the green,safe and high efficiency mining,and the demonstration and leading role projects such as the low-waste and high-efficiency back fill mining.Since 2016,10 R&D projects have been funded,and 122 institutional participants with a total budget of RMB 235 million from the central government and RMB 480 million from enterprises as well as local governments have been involved.It is expected that the mining section of DREAM would contribute to establishing the theory and technology system in the area of deep mining and promoting the ability of deep resource exploitation in China. 展开更多
关键词 resource of deep earth MINING theory general technology application demonstration
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An Analysis of Labor Resources “One River and Two Tributaries” Region in Tibet, China
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作者 PENGChuan-zhong LIXiang-mei +1 位作者 LIUJian ZHONGXiang-hao 《Wuhan University Journal of Natural Sciences》 CAS 2005年第4期751-758,共8页
Focusing on the region of Yarlung Zangbo River and the middle reaches of itstwo tributaries of Nianchu River and Lhasa River in Tibet (Hereafter referred to as the 'One Riverand Two Tributaries' region), and b... Focusing on the region of Yarlung Zangbo River and the middle reaches of itstwo tributaries of Nianchu River and Lhasa River in Tibet (Hereafter referred to as the 'One Riverand Two Tributaries' region), and based on the data from China 3rd, 4th and5th population censuses,the article has analyzed change patterns of this region' s labor force. Major findings from thestudy are summarized as follows; (1) Compared with the data from the 3rd census, labor forcepopulation in 2000 has increased significantly. (2) Children dependency coefficient has dropped,while old people dependency coefficient has changed very slightly with an increase of 0. 047% only.(3) Compared 2000 with 1982, illiteracy and semi-illiteracy rate of the population above 15 yearsold have decreased significantly by 30. 69 percentage points, but still higher than the nationalaverage. (4) Women' s illiteracy rate has dropped faster than men's, but up to 2000 it was generallyquite high. The upgrading of the entire population's overall quality has a long way to go. 展开更多
关键词 labor force resources children dependency coefficient old people dependencycoefficient labor force' s education level One River and Two Tributaries region
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China's Graphite Resources and the Supply-Demand Situation
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作者 LIU Lian LIU Zhiqiang +4 位作者 HUANG Min FEI Hongcai ZHOU Jian ZHANG Yuxu HAO Ziguo 《Acta Geologica Sinica(English Edition)》 CAS CSCD 2018年第4期1645-1646,共2页
Graphite is a rare and important nonmetallic mineral. Till 2017, the global graphite resource reserves had exceeded one billion tons, which are mainly distributed in China (0.45 billion tons), Mozambique (0.14 bill... Graphite is a rare and important nonmetallic mineral. Till 2017, the global graphite resource reserves had exceeded one billion tons, which are mainly distributed in China (0.45 billion tons), Mozambique (0.14 billion tons), Madagascar (0.1 billion tons), Turkey (0.09 billion tons), Brazil (0.07 billion tons), and Tanzania (0.07 billion tons). These six countries include about 92% of the global graphite resource reserves, of which China accounts for about 45% of the world's total resource reserves. 展开更多
关键词 GRAPHITE In China’s Graphite resources and the supply-Demand situation
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The Study of Woodland Use Efficiency from the Perspective of Forest Resources Change
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作者 Shaozhou ZHOU Min LIU 《Asian Agricultural Research》 2014年第4期103-107,111,共6页
From the perspective of forest resources change,this article uses comparative analysis and panel data regression to study the woodland use efficiency from forest resources quantity and quality change.The results show ... From the perspective of forest resources change,this article uses comparative analysis and panel data regression to study the woodland use efficiency from forest resources quantity and quality change.The results show that although the forest coverage and forest stock volume per hectare show an overall upward trend,there are different change laws between the two;there are also differences in the influencing factors between forest coverage and forest stock volume per hectare( population density,rainfall and project having significant effect on forest coverage;population density,economic density and institution having significant effect on forest stock per hectare).Finally the recommendations are put forth for improving the woodland resources use efficiency:it is necessary to improve both the forest quantity and forest quality,focus on demand and supply,and pay equal attention to project promotion and property rights system reform. 展开更多
关键词 WOODLAND FOREsT resources FOREsT COVERAGE FOREsT s
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