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81.
王天民 《华北地质矿产杂志》1999,(2)
本文详细分析了黄金矿产地质勘查、矿山建设及金矿生产等阶段工作的特点及其相互关系,探索性地提出提前建矿,缩短探矿和建设周期的办矿方式,并就如何加快黄金发展步伐问题提出了几点思考。 相似文献
82.
河北唐山地区盛汛期短时强降水概念模型及物理量特征分析 总被引:1,自引:0,他引:1
利用2006-2013年区域自动站降水资料以及NCEP再分析资料,应用EOF分析和中尺度天气图分析等方法对唐山地区盛汛期短历时强降水的时空分布特征、天气学概念模型以及物理量特征进行研究.结果表明:唐山东北部是短时强降水的活跃区、西南部为不活跃区,但西南部极端短时强降水更强;存在5种降水空间分布类型,分别是“一致型”“西北多型”“东南多型”“东北异常偏多型”“东北异常偏少型”.700 hPa切变线是否断裂、副热带高压及高低空急流的位置以及高低空干湿区配置决定了降水分布;短时强降水发生时局地水汽丰富,暖云层厚度较大,垂直风切变较弱,存在一定的不稳定能量,强天气威胁指数较小、0℃层较高,大多数类型都有强的水汽辐合,但“东北异常偏多型”辐合较弱,其水汽主要来源于本地. 相似文献
83.
In this paper, a novel algorithm for aerosol optical depth(AOD) retrieval with a 1 km spatial resolution over land is presented using the Advanced Along Track Scanning Radiometer (AATSR) dual-view capability at 0.55, 0.66 and 0.87 μm, in combination with the Bi-directional Reflectance Distribution Function (BRDF) model, a product of the Moderate Resolution Imaging Spectroradiometer (MODIS). The BRDF characteristics of the land surface, i.e. prior input parameters for this algorithm, are computed by extracti... 相似文献
84.
85.
Peter Caithamer 《Mathematical Geosciences》2008,40(6):653-670
This paper analyzes world oil production data as a population/resource growth model. Both US and world oil production data
are analyzed in terms of the logistic growth curve. It is shown that the logistic growth curve, while a suitable model for
the American data, is not a suitable model for world oil production. A flexible family of curves which allows a wide range
growth rates is considered. Using a nonlinear regression, one can predict various peak dates and total recoverable resources
using different curves which all fit the data indistinguishably well. 相似文献
86.
87.
城市中心商业区内部功能与步行街 总被引:5,自引:0,他引:5
本文研究城市中心商业区商务,居住,交通等内部功能方面的问题,并提出有关在中心商业区设置步行街的一些见解。 相似文献
88.
Multi-biomarkers were characterized in surface soils with different vegetation during an annual cycle in Oregon, U.S.A., to study the composition and dynamics of soil organic matter (SOM). The major compound classes identified include saccharides, steroids, terpenoids, and homologous series of aliphatic lipids (n-alkanoic acids, n-alkanols, and n-alkanes). Saccharides, n-alkanoic acids, and sterols were the most dominant compound groups identified in Ryegrass field soils, whereas n-alkanoic acids, n-alkanols, and sterols were dominant in soils under conifer and deciduous vegetation. Plant species, instead of microbial organisms, was found to be the primary source influencing the concentration and distribution of the major biomarker tracers in the studied surface soils. Over an annual cycle, concentrations of higher plant lipids such as monoacyl glycerides, sterols, n-alkanoic acids and total wax were higher during summer (especially June–August). During fall into winter, the concentrations of all compounds decreased to steady state levels due to cessation of de novo synthesis and concomitant biodegradation and remineralization of detritus. Sucrose and glucose reached maximum concentrations during spring (especially March–May), which could be related with plant growth, especially rootlets in the soils. Mycose, the microbial/fungal metabolite, maximized during late summer, suggesting the concomitant increase of microbial/fungal activity with the increasing primary production. The composition and variation of biomarkers observed over an annual cycle improved our understanding of SOM dynamics in temperate soils, which could also be linked to regional and global carbon cycles. 相似文献
89.
作者近十年来在研究痕量金属离子的水-汽界面转移时,发现宏观热力学无法解释转移机制,而微观量子化学及键参数与离子转移浓度之间,却存在函数关系——顾函数。即水蒸发时水汽带出的Zn2+等离子浓度C(μg/L),正相关于比电子亲和常数IZ/Z(eV)(与水合力相关),负相关于离子体积V(3)及配位数N(与水合数相关)。本研究运用顾函数方法进行水-汽离子通量(F)计算,结果表明,世界海洋的F=C×0.35(1012g/a),黄海的F=C×0.42(109g/a),揭示了自然规律。水汽化学离子浓度测定的可靠性,已由生物毒性实验证实。 相似文献
90.
Fully coupled global analysis of Floating Production Systems, including the vessel, the mooring system and the riser system is described. Design of the system can be a daunting task, involving more than 1000 load cases for global analysis. The primary driver for the mooring system and for the riser system is motion of the vessel. Vessel motions are driven by environmental forces, but are restrained by forces from the mooring and riser systems. Numerical models and procedures that provide accurate and efficient global modeling of the Floating Production System are presented. Both Time Domain and Frequency Domain procedures are included. The accuracy and efficiency of the procedures are illustrated in an example: a large semi with 16 mooring lines and 20 risers. The procedures provide the accuracy and efficiency for use of fully coupled analysis in design of Floating Production Systems from concept selection to final design, installation and operation. 相似文献