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171.
介绍了太阳位置的确定方法,并通过计算给出了全省气象观测台站的日出、日落方向的太阳方位角变化结果以及每个台站一年中正午时刻太阳高度角变化范围。 相似文献
172.
数字航空影像辐射信息精处理问题的探讨 总被引:1,自引:0,他引:1
在分析数字航空影像辐射信息的基础上,针对数字航空像片的特点,探讨对数字航空影像进行匀光和匀色处理的技术方法,以及实现批量化处理的方法研究。 相似文献
173.
Aloísio J.B. Cotta Jacinta Enzweiler Stephen A. Wilson Carlos A. Pérez Antonio J.R. Nardy João H. Larizzatti 《Geostandards and Geoanalytical Research》2007,31(4):379-393
Reference materials (RM) are required for quantitative analyses and their successful use is associated with the degree of homogeneity, and the traceability and confidence limits of the values established by characterisation. During the production of a RM, the chemical characterisation can only commence after it has been demonstrated that the material has the required level of homogeneity. Here we describe the preparation of BRP-1, a proposed geochemical reference material, and the results of the tests to evaluate its degree of homogeneity between and within bottles. BRP-1 is the first of two geochemical RM being produced by Brazilian institutions in collaboration with the United States Geological Survey (USGS) and the International Association of Geoanalysts (IAG). Two test portions of twenty bottles of BRP-1 were analysed by wavelength dispersive-XRF spectrometry and major, minor and eighteen trace elements were determined. The results show that for most of the investigated elements, the units of BRP-1 were homogeneous at conditions approximately three times more rigorous than those strived for by the test of "sufficient homogeneity". Furthermore, the within bottle homogeneity of BRP-1 was evaluated using small beam (1 mm2 ) synchrotron radiation XRF spectrometry and, for comparison, the USGS reference materials BCR-2 and GSP-2 were also evaluated. From our data, it has been possible to assign representative minimum masses for some major constituents (1 mg) and for some trace elements (1-13 mg), except Zr in GSP-2, for which test portions of 74 mg are recommended. 相似文献
174.
Surface oscillations — A possible source of fracture induced electromagnetic radiation 总被引:1,自引:0,他引:1
Radio frequency electromagnetic radiation (EMR) registered hundreds of kilometres away from an earthquake epicentre is detected hours before earthquakes. Yet, accurate earthquakes prediction by their self-induced EMR still remains in its infancy due in part to the lack of understanding of EMR's origin. Here we present a viable model of this origin, according to which EMR is emitted by an oscillating dipole created by ions moving collectively as a surface wave on both sides of the crack; when the crack halts, the EMR pulse amplitude decays by interaction with bulk phonons. The model is shown to be able to provide crack dimensions and velocities, to explain some general similarities of different fracturing processes and indicate the existence of a general failure mechanism. Results raise the hope of developing an EMR based genuine earthquake prediction system. 相似文献
175.
利用昌吉市1961—1997年的逐日气候资料,对昌吉市1961—1997年多年平均逐日太阳总辐射进行了气候学计算,并分析了其变化特征和变化趋势,结果表明:昌吉市太阳总辐射多年平均年日总量为22.82MJ.m-2.d-1,太阳总辐射在8~9月份最高,12月份最低,昌吉市的太阳总辐射呈逐年下降趋势。 相似文献
176.
We test a new emission mechanism in pulsar magnetospheres, eventually responsible in part for the high level of observed radio radiation. This is carried out by comparing the efficiency of the two-stream instability of Langmuir waves in a pulsar emission region, where the stationary and non-stationary characters of pair plasma outflows produced in the gap region are characterized by two different time-scales. On the shorter time-scale, the Ruderman &38; Sutherland 'sparking' phenomenon leads to the creation of pair plasma clouds, in motion along magnetic field lines, that contain particles with a large spectrum of momenta. The overlapping of particles with different energies produced in successive clouds results in an efficient 'two stream'-like instability. This effect is a consequence of the non-stationary character of the pair plasma produced in the gap region, just above the magnetic poles of the neutron star. On a long time-scale, resulting pair plasma outflows in pulsar magnetospheres can be treated as stationary. In this case, the instability which results from interaction between existing primary beam particles and the pair plasma is negligible, whereas the instability owing to interaction between electrons and positrons of the pair plasma itself, and more precisely to their relative drift motion along curved magnetic field lines, is effective. We derive characteristic features of the triggered instability, using specific distribution functions to describe either particles in the assembly of clouds or relative drifting of electrons and positrons in these same plasma clouds. Although linear and local, our treatment suggests that non-stationary effects may compete with, or even dominate over, drifting effects in parts of pulsar emission regions. 相似文献
177.
煤层自燃是中国北方煤田中普遍存在的灾害现象,它不但烧掉了大量的煤炭资源,而且还污染了环境。实践证明,利用遥感影像判别火区位置、圈定火区范围和对火区进行动态监测,及时为灭火工程提供信息,是一项经济和社会意义很大的工作。由于受多种因素的制约,不同地区、不同波段、不同时相、不同空间分辨率的遥感图像,其影像特征(含与煤层自燃有关的热异常影像特征)都有较大的差异,因而从图像上分析和提取地物的热红外辐射特征时,需要考虑遥感图像类型、成像时间、地形条件、气象条件和岩性特征等因素的影响。本文着重讨论了地表辐射温度与上述各项因素之间的关系。 相似文献
178.
基于地理信息系统的太阳直接辐射与冰川物质平衡的关系 总被引:4,自引:1,他引:3
基于冰川微地形对冰川物质平衡重要影响的认识,在考虑朝向、坡度、地形遮蔽等因素的条件下,以地理信息系统为手段,对乌鲁木齐河源1号冰川冰面太阳可能直接辐射进行了理论计算.在此基础上,建立了计算冰面任意一点物质平衡的B=f(T,R)(气温-辐射)模型.比较了该模型与B=f(T)(气温)模型、B=f(P,T)(降水-气温)模型及B=f(Q)(能量平衡)模型之间的优缺点,表明该模型具有物理意义明确、计算精度较高、参数易于获得等优点,从而为计算冰川物质平衡提供了新的途径. 相似文献
179.
本论文对交城花岗岩体的地质环境、工程力学和理化特征作了初步研究。认为交城岗花岩体的地质构造稳定、水文地质条件良好,岩性均匀,故选择交城花岗岩作为研究主岩,并对典型核素在填隙物和花岗岩上的吸附性能进行了试验。 相似文献
180.
Experimental study on the mechanism of non-synchronism of seismo-electromagnetic radiation precursors 总被引:1,自引:0,他引:1
IntroductionThrough20-oddyears’observationandstudyafterthe1976Tangshangreatearthquake,theseismo-electromagneticradiationprec... 相似文献