排序方式: 共有69条查询结果,搜索用时 259 毫秒
11.
The existing oil import dependence index cannot exactly measure the economic cost or scales, and it is difficult to describe the economical aspect of oil security. To measure the foreign dependence of one country's economy and reflect its oil economic security, this paper defines the net oil import intensity as the ratio of net oil import cost to GDP. By using Divisia Index Decomposition, the change of net oil import intensity in five industrialized countries and five newly industrialized countries during 1971—2010 is decomposed into five factors: oil price, oil intensity, oil self-sufficiency, domestic price level and exchange rate. The result shows that the dominating factors are oil price and oil intensity; moreover, the newly industrialized countries have higher net oil import intensity than industrialized countries. 相似文献
12.
本文结合国内外研究状况,分析了寒冷地区水泥混凝土路面耐久性的影响因素,提出了科学的耐久性评定方法,为深入研究提供了参考和依据。 相似文献
13.
王策 《延边教育学院学报》2010,24(1):48-50
本文阐述了计算机网络安全的现状以及影响网络安全的主要因素,针对目前常见的网络安全隐患提出了有效防范网络不安全因素的一些策略,以确保计算机网络的安全管理与有效运行. 相似文献
14.
As China’s energy intensity fluctuated in recent years, it is necessary to examine whether this fluctuation happened at a regional level. This paper establishes a decomposition model by using the structural decomposition analysis (SDA) method at a regional level. Then this model is employed to empirically analyze the changes of Beijing’s energy intensity. The conclusions are as follows: during 2002-2010, except petroleum, the energy intensity decreased and the changes were mostly attributed to the technology changes, while the final use variation actually increased the energy intensity; comparing different periods of 2002-2010, the decline rates of energy intensity for coal and hydropower were decreasing, resulting from the production technology being more energy-intensive than before; the energy intensity changes of petroleum firstly increased substantially and then decreased moderately. 相似文献
15.
玻璃纤维增强聚氨酯基(GFRP)复合材料是一种轻质高强的新型材料,GFRP圆管是输电钢塔筒、通讯钢塔筒和钢制路灯杆的有效替代材料,可承受水平荷载作用下的弯剪作用.组成GFRP圆管的材料是玻璃纤维和聚氨酯,配比为(0.60~0.65):(0.40 ~0.35),通过拉挤缠绕方式成型.对GFRP圆管进行直接弯曲试验,研究其弯曲性能,试验结果表明:GFRP圆管在荷载较小时基本保持整体变形,荷载—位移(应变)曲线保持线性增长;荷载达到45 kN后,GFRP圆管在加载点和支点处发生局部屈服,荷载—位移(应变)曲线增长速度加快;荷载达到50 kN后,GFRP圆管出现强化现象,荷载—位移(应变)曲线增长速度减慢;最终破坏模式为复合材料层间剪切分层的局部屈服褶皱破坏,但卸载后屈服变形可以恢复,表明GFRP圆管具有较强的恢复能力.根据美国ANSI/AISC 360-10和澳大利亚AS4100规范对GFRP圆管的局部屈服抗弯承载力进行计算,发现规范计算值和试验值相差小于10%. 相似文献
16.
17.
康德虽然对分析判断和综合判断做出了明确区分,但弗雷格认为分析与综合仅仅是一种主观性和准心理行为.弗雷格从批判康德的判断理论入手,通过谓词逻辑的构造,成功地清除了康德在判断理论中隐藏的逻辑与心理的混淆,为哲学从认识论走向逻辑语义学奠定了基础.然而,后者倡导的现代量词理论、逻辑的形式主义、判断先于概念以及把"函项/自变元"作为判断结构的现代逻辑思想,又深深地扎根于康德的先验逻辑中,这一点恰好弥合了两类不同逻辑类型的对立,达到了某种内在的一致和统一. 相似文献
18.
19.
数学新课程标准要求教师在教学中特别要注意展现数学问题的背景,要注重数学问题情境的创设.创设数学问题情境过程中应关注以下几组关系:形式和内容,预设和生成,同一性与多样性,生活化与数学化,继承和创新. 相似文献
20.
张萱的仕女画设色工整浓艳、用笔工整妍巧,又善于用点簇法画亭台、树木、花鸟等宫廷景物。他的《虢国夫人游春图》和《捣练图》,不但在当时是一流的反映现实生活的优秀作品,也是代表着盛唐人物画的传世杰作。本文着重介绍盛唐时期张萱的《捣练图》,以及它的艺术特色和审美取向。 相似文献