论我国河流水环境容量空间分异与工业生产力的宏观布局   总被引：7，自引：2，他引：5  

鲍全盛  姜文来 《地理科学》1998,18(3):205-212

在分析我国各地区经济发展与河流水环境容量资源之间矛盾关系及其成因的基础上,揭示了水环境容量与生产力宏观布局之间的关系,并探讨了根据河流水环境容量条件进行生产力宏观布局与调整产业结构的策略。水环境容量是影响生产力宏观布局的重要因素之一,在工业生产力布局时,如果能充分考虑水环境容量资源的承载力,则能够以最小的经济代价,换取最佳的环境效益,使经济与环境得以持续、协调发展,促进区域经济增长。  相似文献   

淮河流域洪涝变化吸引子维数研究   总被引：15，自引：1，他引：14  

周寅康  包浩生 《地理科学》1998,18(4):362-367

淮河流域洪涝序列的功率谱表现出了较好的混沌谱特征,这是序列呈分形结构的内在原因。洪涝序列及其不同平滑序列的关联维数表明,序列平滑程度越大,关联维数越小,关联维数反映了序列所在系统的层次,是系统结构复杂性的重要量度,是 系统建模所需独立变量的控制参数。要恰当地描述淮河流域洪涝发生系数,需构造至少５个状态变量的动力学系统。  相似文献   

颅脑外伤分类的CT特征   总被引：2，自引：2，他引：0  

马蜂  李恒国 《CT理论与应用研究》1998,7(3):22-25

本文目的在于进一步提高对多种颅脑损伤的认识水平。所用材料和方法为本组１３５例,男９８例,女３７例,年龄４＿７７岁,平均年龄２４．８３岁。车祸伤９３例,跌伤２８例,击伤１４伤,１０１例有昏迷史,全部病例均作头颅ＣＴ轴位平扫。从相互伴发的多种颅脑损伤的角度,详细分析了它们的ＣＴ表现。结果得到了１３５例中,有多种类型颅脑损伤１３３例,单纯脑挫裂伤２例;硬膜外血肿１０４例,合并同一部位骨折７５例,占７２．１５％,合并脑挫裂伤占７０．３７％;硬膜下血肿２０例,位于外力对冲部位１５例．占７５％,合并脑挫伤裂伤１２例,其中１１例邻近硬膜下血肿;外伤后２小时内ＣＴ检查,并于外伤后４小时至５天内ＣＴ复查４７例,发现病变进展３８例,占８０．９５％。结论为硬膜外血肿多伴同部位骨折;在硬膜外血肿中,伴发的脑挫裂伤多位于对冲部位;硬膜下血肿多发生于对冲部位;颅脑损伤后,短期内病变可能会继续发展。  相似文献   

贵金属资源的应用及开发   总被引：1，自引：1，他引：0  

唐杰  张凯 《世界地质》1998,17(4):98-102

将贵金属的应用,资源分布,生产和贵金属的分析化学结合在一起进行了综述,由于贵金属资源的短缺性及考虑可持续发展战略,特别介绍了贵金属资源的二次回收问题,并对其将来的发展作了一定的评价和展望。  相似文献   

An Estimation of Internal Soliton Forces on a Pile in the Ocean   总被引：2，自引：0，他引：2  

DU Tao SUN Li ZHANG Yijun BAO Xianwen FANG Xinhua 《中国海洋大学学报(英文版)》2007,6(2):101-106

Internal soliton forces on oil-platform piles in the ocean are estimated with the Morison Formula. Different from sur- face wave forces, which change only in magnitude along a pile, internal soliton forces can be distributed over the entire pile in the water and they change not only in magnitude but also in direction with depth. Our calculations show that the maximum total force caused by a soliton with its associated current of 2.1 m s-1 is nearly equal to the maximum total force exerted by a surface wave with a wavelength of 300 m and a wave-height of 18 m. The total internal soliton force is large enough to affect the operations of marine oil platforms and other facilities. Therefore, the influence of internal solitons should not be neglected in the design of oil platforms.  相似文献   

Statistical analysis of the material source and the modern sedimentary environment of the ferromanganese nodules enriched area of the North Pacific region     

Bao Gende  Yang Qianhong 《中国海洋湖沼学报》1990,8(3):249-256

The source of elements and the modern sedimentary environment of the ferromanganese nodules enriched area of the North Pacific region were analysed statistically and discussed in detail. Cluster analysis shows the area's surface sediments are mainly brown clay and biogenic calcareous, calcsiliceous and siliceous ooze. Factor (principal component) analysis shows that the area's trace elements (Fe, Mn, Cu, Co, Ni, Zn, Cr, etc.) mainly come through adsorption of clay minerals and secondarily from authigenic sediments related to biochemical processes. Bao Gende, 1990. Characteristics of element geochemistry in sediments in the ferromanganese nodules enriched area of the North Pacific region.Acta Sedimentologica Sinica. (in press, in Chinese)  相似文献   

Land cover change detection in West Jilin using ETM ＋ images     

EdwardM.Osei Jr. ZHOUYun-xuan 《东北亚地学研究》2004,7(1):74-84

In order to assess the information content and accuracy of Landsat ETM digital images in land cover change detection,change-detection techniques of image differencing, normalized difference vegetation index,principal components analysis and tasseled-cap transformation were applied to yield 13 images. These images were thresholded into change and no change areas. The thresholded images were then checked in terms of various accuracies. The experiment results show that kappa coefficients of the 13 images range from 48.05-78.09. Different images do detect different types of changes. Images associated with changes in the near-inflared-reflectance or greenness detects crop-type changes and changes between vegetative and non-vegetative features. A unique means of using only Landsat imagery without reference data for the assessment of change in arid land are presented. Images of 12t June, 2000 and 2‘d June, 2002 are used to validate the means. Analyses of standard accuracy and spatial agreement are performed to compare the new images (hereafter called “change images” ) representing the change between the two dates. Spatial agreement evaluates the conformity in the classified “change pixels” and “no-change pixels” at the same location on different change images and comprehensively examines the different techniques. This method would enable authorities to monitor land degradation efficiently and aeculately.  相似文献   

Ⅰ型Seyfert星系的3000包与其在双色图上的表现     

鲍世综  周又元  程福臻  程富华  毛培根 《中国天文和天体物理学报》1990,(1)

本文从Ⅰ型Seyfert星系在双色图上的行为出发,假定可见光与紫外波段连续谱的主要成分包括幂律非热致辐射、黑体辐射、宽线区Balmer连续谱的复合辐射和高阶Balmer线辐射,计算了这些发射机制的参数,发现结果与从分光光度测量决定的参数符合很好。因此,本文结果对已测定色指数的Ⅰ型Seyfert星系可决定出其热致成分(黑体谱和Balmer连续谱)在全部辐射中占的比重;给出了研究类星体的可见光与紫外波段辐射机制的新方法。  相似文献   

Helicity Patterns of the Active Regions Connected by Transequatorial Loops     

Jie Chen  Shudong Bao  Hongqi Zhang 《Solar physics》2007,242(1-2):65-85

Using photospheric vector magnetograms of the Huairou Solar Observing Station and coronal X-ray images from the Yohkoh Soft X-Ray Telescope, we calculate the helicity patterns of 43 pairs of active regions and the chirality of 50 pairs of opposite magnetic polarity regions that are connected by transequatorial loops (TLs). To make the results more convincing, two helicity proxies including the local current helicity h _c and the force-free factor α _best are computed. The results, which are similar for both parameters, are as follows: (1) Current helicity of the active regions pairs connected by transequatorial loops have no obvious regularity: About 50% of the active region pairs carry the same current helicity sign and about 50% of them have the opposite. (2) If we consider the magnetic polarity pairs connected by the TLs, the result is almost the same as that for the active region pairs, with a little more than half of them showing the same chirality. We also make linear force-free extrapolations for 33 TLs and determine their force-free parameter α by comparing extrapolated field lines to X-ray images of the TLs. Out of the 19 cases when the footpoints of the TLs have the same current helicity sign, we find that the sign of α of the TLs is the same as the sign of the current helicity in the footpoints in 12 cases, whereas it is of opposite sign in 4 cases, and in 3 cases the TLs were found to be potential.  相似文献   

Barotropic current fluctuations coupled with sea level drawdown in Yellow and Bohai Seas     

万凯  鲍献文  王毅  万修全  李昊倩  刘珂 《中国海洋湖沼学报》2015,33(1):272-281

Sub-tidal barotropic current variations coupled with residual sea level fluctuation in the Bohai and Yellow Seas during wintertime are addressed in this study.The temporal evolution and spatial distribution of current fluctuation are investigated using moored acoustic Doppler current profiler data in a three-dimensional numerical model.It is found that a southward current followed by a northward current occurred in the northern Yellow Sea during the fluctuation,concurrent with a significant outflow followed by inflow through the Bohai Strait.The process is consistent from surface to bottom and is coupled with remarkable residual sea level fluctuation.This quasi three-day fluctuation with amplitude 0.2-0.3 m/s leads to 1 m/1.2 m drawdown in the northern Yellow and Bohai Seas,respectively,strongly influencing water exchange between those seas.Because this a prominent feature in the seas,it is necessary to evaluate its effect on fluctuation during winter in future studies,in particular,the northward current during the recovery phase of sea level in the Bohai and Yellow Seas regarding seasonal variation.  相似文献