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1.
近年来,低碳理念在全球范围内广泛传播,低碳发展成为世界各国关注的焦点.发达国家站在保护全球生态环境的道德制高点上,积极倡导和推动全球低碳发展.发展中国家在坚持继续遵守相关公约和“共同但有区别的责任”原则基础上,谋求适度的低碳发展.中国本着对人类、对未来高度负责的态度,积极响应低碳发展理念.低碳发展不仅是应对气候变化的需要,更是实现社会、经济、环境和谐发展的需要.  相似文献   

2.
A magnetohydrodynamic model of the solar wind flow is constructed using a kinematic approach. It is shown that a phenomenological conductivity of the solar wind plasma plays a key role in the forming of the interplanetary magnetic field (IMF) component normal to the ecliptic plane. This component is mostly important for the magnetospheric dynamics which is controlled by the solar wind electric field. A simple analytical solution for the problem of the solar wind flow past the magnetosphere is presented. In this approach the magnetopause and the Earth's bow shock are approximated by the paraboloids of revolution. Superposition of the effects of the bulk solar wind plasma motion and the magnetic field diffusion results in an incomplete screening of the IMF by the magnetopause. It is shown that the normal to the magnetopause component of the solar wind magnetic field and the tangential component of the electric field penetrated into the magnetosphere are determined by the quarter square of the magnetic Reynolds number. In final, a dynamic model of the magnetospheric magnetic field is constructed. This model can describe the magnetosphere in the course of the severe magnetic storm. The conditions under which the magnetospheric magnetic flux structure is unstable and can drive the magnetospheric substorm are discussed. The model calculations are compared with the observational data for September 24–26, 1998 magnetic storm (Dst min=−205 nT) and substorm occurred at 02:30 UT on January 10, 1997. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

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基于能量意外释放理论和事故三角模型,并通过对比和借鉴一般作业风险评价方法(LEC法)的有关内容,对能量跟踪与屏障分析方法(ETBA法)的计算过程进行了进一步的思考.并尝试应用其来量化预先危险性分析方法(PHA法)分析的结果,这样可以使得PHA分析结果具备伞面与重点兼顾、定性与定量结合的效果,并且使危险等级的划分更加明确,使其能为进一步的危险分析及建设项目的设计、整改工作提供更为切实的依据.  相似文献   

5.
The present status of abundance information for elements in meteorites and in the Sun is reviewed, and a new table of abundances of the elements, which should be characteristic of the primitive solar nebula, is compiled and presented. Special attention is called to the elemental abundances in the silicon-to-calcium region, where many of the abundances are rather poorly determined, and where these abundances have an impact on theories of nucleosynthesis of the elements. To each elemental isotope is assigned a mechanism of nucleosynthesis which may have been responsible for production of most of that isotope, and brief comments are made concerning the present status of understanding of the different mechanisms of nucleosynthesis.This paper not presented at the Symposium on Cosmochemistry.  相似文献   

6.
通过对人为因素的理论研究,着重从人机环境系统方面分析了飞机维修工程中出现人为差错的原因,提出了以人为中心的避免人为差错的思路与方案。  相似文献   

7.
郭圣洪 《飞机工程》2005,(4):70-72,78
阐述了在网络环境下档案编研工作的特点,针对网络环境改变了传统的档案编研载体形式,改变了传统的编研模式,丰富了档案编研的技术手段,提出了网络环境下档案编研工作的方法与途径以及如何深化拓展编研工作的对策。  相似文献   

8.
对于清代前期的统一,我们既要看到它的深远影响,也应指出其严重失误。诸如排斥汉族将帅参与边疆事务,在边疆某些地区滥施淫威,对蒙古及黄教政策的消极影响,虚边政策的危害,闭关自守政策的恶果等等,结果很快从“盛世”坠入“衰世”,内忧外患,纷至沓来,到清末时已是不可救药了。  相似文献   

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本文论述了三种景深控制形式与艺术内容表现、艺术价值创造的关系。  相似文献   

10.
中国零售业市场已向WTO成员国全面开放,面对每年近三万多亿元人民币的零售业大市场和国际跨国零售商的全面竞争,并购已经成为民族零售企业迅速形成规模化经营的有效途径。政府可以通过制定相关法律法规、鼓励并购与退出、打破地方保护主义、指导并购后企业整合等政策主导作用来推动和促进民族零售企业的并购。  相似文献   

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