Subjects: Geosciences >> Geography submitted time 2024-07-04 Cooperative journals: 《干旱区研究》
Abstract： In order to explore the spatial-temporal dynamic change characteristics and driving factors of ecological environment in Yanchi County. Taking remote sensing images from 1990 to 2020 as data source, on the basis of the SA-RSEI. Combined with Theil-Sen Median analysis, Mann-Kendall significance test and Hurst index, the spatial-temporal variation pattern and change trend of ecological environment quality in Yanchi County were analyzed. The driving factors of ecological environment quality in Yanchi County were explored by using Geography Detector. The results showed that: (1) SA-RSEI in Yanchi County decreased first and then increased from 2000 to 2020. (2) The ecological environment quality of Yanchi County showed an evolution process of degradation first and then recovery in 21 years. The spatial distribution pattern gradually changed from poor in the south and good in the north to good in the southeast and poor in the northwest. (3) During the 21 years, the ecological environment quality of Yanchi County generally showed a slow degradation trend, but the degree of degradation gradually decreased, and the degree of ecological environment improvement will gradually increase after 2020. (4) DI, precipitation, elevation, and GDP are the main factors influencing the spatial variation in regional ecological quality. (5) The interaction between DI, temperature, precipitation and elevation and other detection factors plays a leading role, the influence of economic factors on SA-RSEI gradually increases.
Subjects: Statistics >> Social Statistics submitted time 2024-06-28 Cooperative journals: 《中国科学院院刊》
Abstract： The foundation for ecological protection and high-quality development in the Yellow River Basin lies in the rational development of industry. This study systematically analyzes the current state of industrial development in the Yellow River Basin, examining traditional industries, strategic emerging industries, and future industries. Based on this analysis, it identifies key issues and development directions. The study reveals that the industrial structure in the Yellow River Basin is unreasonable; traditional industries have short chains and high energy consumption; the cultivation of strategic emerging industries is inadequate and poorly aligned; and comprehensive planning for future industries is inadequate. Therefore, it is imperative to systematically optimize the industrial structure in the Yellow River Basin, promote the transformation and upgrading of traditional industries, accelerate the cultivation of strategic emerging industries through technological innovation, and plan the development of future industries from a holistic perspective. This approach will enhance the momentum and vitality necessary for advancing ecological protection and high-quality development in the Yellow River Basin, contributing to a new chapter in the western development.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-06-21 Cooperative journals: 《应用力学学报》
Abstract：
The existing buckling restrained brace stability design method neglects the stiffness contribution of the inner concrete and the core plate safely,which leads to some errors in the calculation of the overall stability of the brace and can not accurately describe its buckling mechanism.Therefore,this paper will consider the partial stiffness of concrete and core plate,theoretically deduce the calculation formula of the overall stability of the brace,and fit the stiffness reduction factor of concrete and core plate in different composite section braces.Then,the reliability of the finite element model established in this paper is verified by experiments,and numerical simulation is carried out.The results show that the reduction factor fitted in this paper is more applicable and closer to the actual working condition of the brace. The stability formula proposed in this paper can also accurately predict the buckling behavior of braces,and is suitable for braces with different composite sections.Therefore,the stability design method considering the stiffness contribution of concrete and core plate can describe the buckling mechanism of buckling restrained braces more accurately.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： Constructing innovation networks and cultivating innovation corridors are important to realize regional innovation development. Based on the data of patent transfer from 1987 to 2018, this paper analyzes the spatial-temporal evolution of technology transfer network at different scales in the Yellow River Basin, and proposes the cultivation path of Zhengzhou-Luoyang-Xi’an innovation corridor. Firstly, it is found that a majority of technology transfer within the basin is switching from inter-provincial transfer to intra-provincial transfer, with provincial capitals being the main source of technology. Xi’an is the primary source of technology transfer network, and cities, such as Zhengzhou, Qingdao, and Jinan, are secondary sources. Moreover, the technology sources outside the Yellow River Basin are mainly located in the Beijing-Tianjin-Hebei, Yangtze River Delta, Pearl River Delta and other developed urban agglomerations. In addition, Xi’an, Jinan, Qingdao and other high-level central cities have become the main receiving areas of technology transfer. This study concludes that the construction of inter-provincial innovation network should focus on the construction of Zhengzhou-Luoyang-Xi’an innovation corridor, in order to realize the matching and coordination of industrial technological advantages and technological demands of different cities, promote the construction of Zhengzhou-Luoyang-Xi’an high-quality development cooperation belt, and then accelerate the innovation-driven development process of the Yellow River Basin.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2018-06-24 Cooperative journals: 《中国科学院院刊》
Abstract：中亚地区石油资源预测储量巨大，在世界能源地缘格局中具有重要战略地位，对中国推进石油进口多元化战略和扩大陆上管道石油进口具有重要作用。文章分析了中亚地区石油资源对中国的保障程度，发现虽然中国对中亚地区石油的投资力度在不断加大，但中亚地区石油对中国石油进口的保障率却极低。通过构建跨国石油投资的风险评价指标体系，运用模糊综合评价模型，对中亚地区石油投资的风险进行了定量评价，发现政策法规风险属于高风险，经济风险、社会文化风险和政治风险属于一般风险，基础设施风险属于低风险，其中矿业权设置、东道国对经营的干预程度、民族文化宗教差异等7个指标具有相当高的高风险发生概率。未来对中亚地区的石油投资合作，既要依据风险评估结果科学合理规避风险，又要寻求破解之道，选择互利共赢的合作模式，确保在中亚地区石油资源开发领域中的优势地位。
Subjects: Other Disciplines >> Synthetic discipline submitted time 2018-06-24 Cooperative journals: 《中国科学院院刊》
Abstract：中亚地区是“丝绸之路经济带”建设的战略枢纽地段、世界战略能源富集区和超级大国争夺及政治博弈的重点地区之一，也是我国战略能源优先保障的最近基地。中亚战略能源（石油、天然气和天然铀）开发利用表现为储量大、产量小、出口量大、自消量小的“两大两小”特点，这些能源的合作开发利用对中国的保障程度有大有小。研究表明，预计到2030年中国石油、天然气、天然铀的对外依存度将分别高达80%、55%和70%，而同期中亚地区石油、天然气和天然铀出口对中国的保障程度分别为7.9%、40.7%和65%左右。受中亚地区政治、经济、政策、法律、社会文化等因素综合影响，中国与中亚地区合作开发利用战略能源面临的法律、经济、社会、政治、基础设施风险不可低估。其中，法律风险属于高风险，经济风险属于较高风险，社会风险和政治风险属于一般风险。中国与中亚合作开发战略能源一定要时刻防范风险，从化解风险、增进合作、互利共赢的角度，明确政府角色，保证政策沟通，建立副总理级战略能源开发协调委员会；发挥地缘区位优势，设立中国-中亚能源自由贸易区；完善基础设施，实现互联互通，加强中亚能源开发战略运输通道建设；建立能源战略储备制度，建立国家战略能源联合储备体系；加强人文合作，促进民心相通，降低战略能源合作风险。
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