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911.
This paper analyzes the advantages and disadvantages of two techni-cal lines for automatic group generalization of contour lines.The author suggeststhat it is possible to get faster and better generalization results if we simulate theintelligence of human experts in program designing,retrieve geomorphologicalstructural information using the input data of 2-D contour lines and derive andoutput the generalied 2-D results directly. 相似文献
912.
给出4点组斜率信息法的理论模型,分析了大同台短水准测量结果,证明几次中强地震前大同台短水准均有明显的中、短期异常;同时发现跨断层测站高差曲线能较好地反映震前短、临异常的变化。 相似文献
913.
赵虹 《地球科学与环境学报》1998,(Z1)
北山盆地群侏罗系和下白垩统砂岩储层主要属长石岩屑砂岩和岩屑长石砂岩,其次为岩屑砂岩,成分和结构成熟度均较低;储层孔隙类型以次生孔隙为主,孔隙结构及物性总体较差。储层分类评价及综合分析表明,中侏罗统储层属较有利储层,在北山盆地群具有较重要的储集意义。 相似文献
914.
915.
《Icarus》1979,37(2):467-474
In September 1977, a crater studies workshop was held for the purpose of developing standardized data analysis and presentation techniques. This report contains the unanimous recommendations of the participants. This first meeting considered primarily crater size-frequency data. Future meetings will treat other aspects of crater studies such as morphologies. 相似文献
916.
To investigate the combined effects of decreasing taxonomic resolution (i.e. species, family, phylum), the use of different mesh-size (1.0 mm and 0.5 mm) and the type of samplers used (van Veen vs. corers taken by divers) on the quality of data obtained, a comparative study was undertaken with the overall aim of identifying cost efficient methods for routinely monitoring the ecological change caused by Mediterranean fish farming. The results clearly showed that information loss was relatively low as data were aggregated at higher taxonomic levels, particularly up to the level of family or even order. It was also found that the extra information gained by sieving samples through a 0.5 mm sieve did not improve the ability to distinguish the potentially impacted sites from the control stations. Finally, it was found that a relatively large proportion of the available information concerning the community structure such as abundance, biomass or diversity is lost when sampling is carried out with corers. A cost/benefit ratio analysis for the two sampling and the two sieving methods showed minimal values for the van Veen samples (for both sieve fractions) at the family level, indicating that analysis at this level gives the best balance between precision of the results and decrease in taxonomic effort. However, if the time needed to sort the samples is included in the analysis, then samples taken with corers using a 0.5 mm sieve and identified to families seems like a good compromise between precision and cost. 相似文献
917.
The correlation of multi-angle thermal infrared data and the choice of optimal view angles 总被引:1,自引:0,他引:1
FAN Wenjie & XU Xiru .Institute of Remote Sensing GIS of Peking University Beijing China .Center of Remote Sensing GIS of Beijing Normal University Beijing China 《中国科学D辑(英文版)》2004,47(6):570-576
The relationship between multi-angle thermal in-frared radiance of non-isothermal mixed pixel and black bodys radiance of components can be expressed by the matrix formula[1] ,()()(),kkjbjLwLTllq= (1) here l represents wave length of electronic magnetic wave, kq means zenith angle of view direction, (,)LTlq means the measured radiance, ,()kjw is called the matrix of system抯effective emissivities, T means the temperature in K degree, ()bLTl means the radiance of black body described by plank… 相似文献
918.
Zhou Jiabao Zhang Jiachang Senior Engineer River Harbour Department Nanjing Hydraulic Research Institute Nanjing 《中国海洋工程》1992,(1)
-The effect of wave group on wave run-up on a slope dike is mainly discussed in this paper. Two simulating methods of wave group and their applications in laboratory are introduced. Synthesizing the research results of wave run-up on a slope dike, the effect of wave group on wave run-up on a slope dike in coastal protection engineering is studied as the main point. 相似文献
919.
Zuo Qihua Yao Guoquan
Engineer Nanjing Hydraulic Research Institute Nanjing
Senior Engineer Nanjing Hydraulic Research Institute Nanjing 《中国海洋工程》1991,(2)
The second order long waves of the mean water free surface displacement induced by the wave groups over a trench are discussed in this paper. The incident wave groups are supposed to be superposed by 2 linear waves with different amplitudes, phases and slightly different frequencies. Some of the theoretical formulas and numerical results are presented. 相似文献
920.
A short history of Ocean Station Papa and Line P 总被引:1,自引:0,他引:1
Howard Freeland 《Progress in Oceanography》2007,75(2):120-125
This short article summarises the origins of observations at Ocean Station Papa, the evolution into Line P and the subsequent history of observations along that line. 相似文献