We summarize the morphological features of spotless flares as observed by three Chinese observatories (Yunnan Purple Mountain and Beijing) during the peak years of the 21st solar cycle. On the basis of the Kippenhahn-Schluter model of solar prominences, we qualitatively interpret these observed features and propose a possible theoretical model of generating spotless flares. 相似文献
According to our Paper I (Cao Shenglin, 1988), it could be supposed that the physical space-time is a Finsler space-time, characterized by the metric ds4=gijkf dxi dxj dxk dxf. If so, a new space-time transformation could be found by invariant ds4 and the theory of relativity is discussed on this transformation.The project supported by National Natural Science Foundation of China. 相似文献
The primordial anisotropy polarization pathfinder array (PAPPA) is a balloon-based instrument to measure the polarization of the cosmic microwave background and search for the signal from gravity waves excited during an inflationary epoch in the early universe. PAPPA will survey a 20° × 20° patch at the North Celestial Pole using 32 pixels in 3 passbands centered at 89, 212, and 302 GHz. Each pixel uses MEMS switches in a superconducting microstrip transmission line to combine the phase modulation techniques used in radio astronomy with the sensitivity of transition-edge superconducting bolometers. Each switched circuit modulates the incident polarization on a single detector, allowing nearly instantaneous characterization of the Stokes I, Q, and U parameters. We describe the instrument design and status. 相似文献
Science China Earth Sciences - The successful return of lunar soil samples from the northern Oceanus Procellarum by the Chang’E 5 (CE-5) mission has provided unprecedented ground-truth... 相似文献
Low-to-medium temperature geothermal fluids in the granite regions of southeastern China are an important renewable energy resource, but they are also a source of contamination containing highly toxic elements such as fluoride and arsenic. This study analyzed the origin of the geothermal fluids in a regional-scale hydrogeological unit in the city of Xiamen, China, based on isotope and hydrochemical analyses. The Br/Cl ratios suggested that the inland geothermal fluid is merely recharged by rainwater from the mountain edge, while the coastal geothermal fluid is originally recharged by the seawater and later mixed with rain-derived groundwater. The geothermal water featured high SiO2 and detectable Zn concentrations. The former reflects the significant water–granite interaction along the flow path, and the latter indicates the active hydraulic connection between surface waters, shallow aquifers and deep geothermal fluids. High radon content was detected near the deep conductive fault adjacent to a geothermal well, demonstrating that the fault damage zone acts as a major conduit for upward transport of the deep geothermal fluid. As a result, the fault damage zones developed in the granite are necessary for the formation of geothermal water, which leads to the uneven distribution of geothermal water in the subsurface. High-temperature geothermal water can be found in those regions with fairly sparse fault damage zones. In contrast, in the region with high-density fault activities, the active communication between shallow cool water and deep geothermal fluids can decrease the water temperature.
To discover the characteristics, distribution and potential of shallow geothermal energy in the Beijing-Tianjin-Hebei Plain area. This paper, based on a large amount of data collection and field investigations, evaluateed the shallow-layer geothermal energy in the study area through the analytic hierarchy process and comprehensive index method. Based on suitability zoning results superimposed with 1:100 000 land use data, the study area is divided into encouraged, controlled, restricted and prospective mining areas regarding the development of shallow geothermal energy, and the economic availability of shallow geothermal energy in the encouraged and controlled areas are evaluated. The results show that the shallow geothermal energy in the Beijing-Tianjin-Hebei Plain can meet the heating and cooling demand of 6×108 m~2 of buildings, equivalent to 1.15×10~7 t of standard coal, thus reducing carbon dioxide emissions by 2.73×10~7 t and reducing sulfur dioxide emissions by 1.95×10~5 t. According to the development and utilization mode, the energy demand level and the Beijing-Tianjin-Hebei coordinated development plan, the development and utilization of geothermal resources in the plain area has two types: Urban concentrated mining areas and rural scattered mining areas. The scale and level of intensive utilization of regional geothermal resources are of great significance. 相似文献