排序方式: 共有42条查询结果,搜索用时 15 毫秒
11.
李明 《郑州航空工业管理学院学报(管理科学版)》2007,25(5):85-88
美国的社会性管制在1995年之后进入了一个全新的发展时期,呈现出一些新的发展趋势。在近百年的发展过程中,美国社会性管制积累了许多成功经验,这些对于正处于经济转型过程中的中国在积极推进社会性体制改革、提高政府管制效益等方面具有重要的启示意义。 相似文献
12.
13.
王培华 《西安航空技术高等专科学校学报》2006,24(6):37-39
韩城,是我国著名的历史学家司马迁的故乡,是我国历史文化名城。但她仅是一座县级城市,一座小城,其经济状况与历史名城极不适应。韩城要发展,重点是要定好位,并给予政策扶持。要以文化产业为先导,振兴旅游业,带动现有的强势工业的改造和升级,发展特色农业,使韩城真正成为一座文化大市,旅游强市,煤炭、电力、钢铁发达,特色农业鲜明的现代化区域中心城市。 相似文献
14.
几何量测量仪器的新进展 总被引:5,自引:0,他引:5
就各类产品要求和几何量测量仪器的发展,并结合这一领域近年最新进展举例阐述其发展动向。 相似文献
15.
16.
C. Jacobi G. Stober D. Kürschner 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,41(9):1429-1434
Scale height, H, estimates are calculated from the decrease/increase of ionospheric virtual reflection heights of low-frequency (LF) radio waves at oblique incidence in suitably defined morning intervals around sunrise during winter months. The day-to-day variations of H qualitatively agree with daily mean temperature variations around 90 km from meteor radar measurements. Since mesospheric long-period temperature variations are generally accepted to be the signature of atmospheric planetary waves, this shows that LF reflection height measurements can be used for monitoring the dynamics of the upper middle atmosphere. The long-term variations of monthly mean H estimates have also been analysed. There is no significant trend, which is in agreement with other measurements of mesopause region temperature trends. 相似文献
17.
U.M. Leloglu E. Kocaoglan 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008
Although it is generally agreed that the outer space should be used for the benefit of all mankind, only a fraction of the countries have the necessary technological base for accessing space. Space technology, with its implications on science, economy and well-being of citizens, is mostly chosen as one of the priority areas for technological development by developing countries. However, there is already an over-capacity in global space industry and there are doubts on necessity of additional capacity establishment by developing countries. In this study, the importance and benefits of capacity-building in these countries are emphasized and the advantages and disadvantages that developing countries have in the framework of space technology acquisition are briefly presented. The feasibility of certain levels of space technology is discussed and the necessity of combining existing indigenous capabilities with technology obtained from foreign sources in the optimal way is stressed. We have also mentioned various general mechanisms of technology transfer and argued the importance of licensing in catching-up developed countries. After considering the necessary conditions of efficiency of technology, such as establishment of regional centers of space science and technology education by United Nations, joint development of space systems, complete technology transfer packages, cooperative space projects within regional organizations, coordinated constellations and special agreements with large space agencies, which are specific mechanisms already in use, are reviewed. Some typical examples of mechanisms are also given with special emphasize on small satellite technology that makes access to space affordable for many countries. Through sharing and analyzing the experience of developing countries in their odyssey of space capacity-building, the difficulties can be negotiated and the vicious circles can be broken. This study, in our view, is a step to incite a general discussion of obstacles and opportunities for developing countries, that could help them in using their limited resources effectively, hence, enable them to offer better conditions to their citizens and to contribute space science to a larger extend. 相似文献
18.
军用无人机技术的发展现状及未来趋势 总被引:1,自引:0,他引:1
作为一种多用途、低费效比的航空武器装备,军用无人机日益受到世界各国军方的重视.本文分析了现役和即将服役军用无人机的技术水平及应用特点,并对军用无人机的发展趋势进行了展望. 相似文献
19.
A.D. Danilov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(1):102-110
The analysis of the behavior of the critical frequency foF2 during the 24th solar activity cycle (Danilov and Konstantinova, 2020a, c) is prolonged for two more months and the nighttime hours. In addition to the Rz and Ly-α indices used in the aforementioned papers for correction of the F10.7 index during the 24th cycle, the commonly used Mg II index is added. The results confirm the previous conclusions on the existence of the “vague” period with chaotic behavior of foF2 and the recovery of the negative trend in foF2 after 2008–2010. A comparison of the F10.7 index with three other SA indices (Ly-α, Rz, and Mg II) for the 22nd, 23rd, and 24th SA cycles is performed. It is shown that the relationship between F10.7 and other indices is close in the 22nd and 23rd cycles but differs from that in the 24th cycle. The corrected values of F10.7 in the 24th cycle are proposed for analysis of ionospheric trends during that cycle. 相似文献
20.