排序方式: 共有15条查询结果,搜索用时 31 毫秒
11.
Evelyn De Wachter Klemens Hocke Thomas Flury Dominik Scheiben Niklaus Kämpfer Soohyun Ka Jung Jin Oh 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
The period January–February 2008 was characterized by four Sudden Stratospheric Warmings (SSWs) in the Northern Hemisphere, of which the last warming, at the end of February 2008, was a major warming. A significant decrease in mesospheric water vapour (H2O) of more than 2 ppmv (∼40%) was observed by the ground-based microwave (GBMW) radiometer in Seoul, S. Korea [37.3°N, 126.3°E] during the major SSW. A comparison with ground-based mesospheric H2O observations from the mid-latitude station in Bern [46.9°N, 7°E] revealed an anticorrelation in the mesospheric H2O data during the major SSW. In addition, prior to the major warming, strong periodic fluctuations were recorded in the Aura MLS vertical temperature distribution between 15 and 0.05 hPa at Seoul. The mesospheric temperature oscillation was found to have a period of ∼10–14 days with a persistency of 3–4 cycles. 相似文献
12.
Kyo-Young Song Hyun-Joo Oh Jaewon Choi Inhye Park Changwook Lee Saro Lee 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
The aim of this study was to identify landslide-related factors using only remotely sensed data and to present landslide susceptibility maps using a geographic information system, data-mining models, an artificial neural network (ANN), and an adaptive neuro-fuzzy interface system (ANFIS). Landslide-related factors were identified in Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite imagery. The slope, aspect, and curvature of topographic features were calculated from a digital elevation model that was made using the ASTER imagery. Lineaments, land-cover, and normalized difference vegetative index layers were also extracted from the imagery. Landslide-susceptible areas were analyzed and mapped based on occurrence factors using the ANN and ANFIS. The generalized bell-shaped built-in membership function of the ANFIS was applied to landslide susceptibility mapping. Analytical results were validated using landslide test location data. In the validation results, the ANN model showed 80.42% prediction accuracy and the ANFIS model showed 86.55% prediction accuracy. These results suggest that the ANFIS model has a better performance than does the ANN in predicting landslide susceptibility. 相似文献
13.
过去20年里线切割的切割速度几乎增加了5倍,粗加工的直线切割速度可达600mm2/min;对大多数复杂型腔的加工速度较慢,但也可达到约350mm2/min。通过优化粗加工和精加工的策略,变质层几乎为零,同时没有材料或微观结构的变化,放电脉冲的控制特别是脉冲的持续时间和频率是达到最小损伤的关键因素。 相似文献
14.
Myung Soo Chung JEONG-SOO Lim Dong Chul Park 《IEEE transactions on aerospace and electronic systems》2006,42(4)
Extraction of elevation information with phased array search radar in the presence of specular reflection from sea surface is presented. Specular reflection from sea causes large peak errors in the measurement of low elevation angle. An algorithm based on complex indicated angle is derived to reduce specular reflection component. From the complex indicated angle and the exactly known or approximately known data, the authors can generate a specular reflection error finding function (SREFF). SREFF clearly indicates where the measurements are much affected by the specular reflection in the complex indicated angle data 相似文献
15.
Development of multi-functional composite structures with embedded electronics for space application 总被引:1,自引:0,他引:1
Tae Seong Jang Dae Soo Oh Jin Kyu Kim Kyung In Kang Won Ho Cha Seung Woo Rhee 《Acta Astronautica》2011,68(1-2):240-252
Conventional spacecraft structural function has been limited to supporting loads and mounting avionics only. In contrast, the technology of ‘multi-functional structures’ can integrate thermal and electronic functions into the spacecraft’s inherent load-bearing capability. In addition, sufficient radiation shielding effectiveness can be provided for the anticipated mission environment. Utilizing this concept, the ratio of electrical functionality to spacecraft volume can be dramatically increased and significant mass savings can be obtained. In this paper, spacecraft electronics are miniaturized using advanced IT applications such as flexible circuitry, miniaturized components, featherweight connectors, and so on, that they can be easily embedded within a structural panel. A sandwich structural panel consists of an aluminum honeycomb core and lightweight CFRP facesheets. Integration of electronics is implemented within the panel by mounting electronics on a multi-layered composite enclosure with multi-materials. This composite enclosure provides a load-bearing, effective thermal conduction, radiation shielding capabilities and an available space for embedding electronics. A series of environmental tests and analyses is carried out to demonstrate that the flight hardware is qualified for the expected mission environments. This approach will be utilized for the advanced small satellite ‘STSAT-3’ to validate the multi-functional structures concept. 相似文献