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311.
新一代双偏振天气雷达在暴雨、台风等灾害性天气监测和预警中发挥了重要的作用。随着气象现代化发展以及预报时效性、精细化度的要求不断提高,S波段新一代双偏振天气雷达已不能充分满足发展过程迅速的中小尺度天气系统的研究、预警。气象雷达的时空分辨率对探测强对流过程中小尺度结构有重要作用,提高天气雷达时空分辨率是精细化探测技术的关键,本文着重从新一代天气雷达的时空分辨率、体扫方式等方面,通过对天气雷达脉冲重复频率、信号处理方法及扫描方式等进行改进,提高新一代双偏振天气雷达对中小尺度气旋和龙卷风等灾害性天气的探测能力,以获取快速变化的天气过程精细化特征,获得更新更快、分辨率更高的观测资料。 相似文献
312.
Efstratios Stylianidis Daniela Poli Martin Hofer Armin Gruen Victor Sanchez Martin 《International Journal of Digital Earth》2020,13(8):854-885
ABSTRACT A 3D forest monitoring system, called FORSAT (a satellite very high resolution image processing platform for forest assessment), was developed for the extraction of 3D geometric forest information from very high resolution (VHR) satellite imagery and the automatic 3D change detection. FORSAT is composed of two complementary tasks: (1) the geometric and radiometric processing of satellite optical imagery and digital surface model (DSM) reconstruction by using a precise and robust image matching approach specially designed for VHR satellite imagery, (2) 3D surface comparison for change detection. It allows the users to import DSMs, align them using an advanced 3D surface matching approach and calculate the 3D differences and volume changes (together with precision values) between epochs. FORSAT is a single source and flexible forest information solution, allowing expert and non-expert remote sensing users to monitor forests in three and four (time) dimensions. The geometric resolution and thematic content of VHR optical imagery are sufficient for many forest information needs such as deforestation, clear-cut and fire severity mapping. The capacity and benefits of FORSAT, as a forest information system contributing to the sustainable forest management, have been tested and validated in case studies located in Austria, Switzerland and Spain. 相似文献
313.
铁岭—昌图盆地上侏罗统砂岩储层次生孔隙形成机制研究 总被引:2,自引:1,他引:2
本文对研究区段上侏罗统砂岩储层的次生孔隙进行以下探讨:①大洼—昌图凹陷砂岩储层次生格架颗粒溶孔和粒间溶蚀扩大孔的形成机制;②张强凹陷砂岩储层次生格架颗粒溶孔和碳酸盐胶结物溶孔的形成机制。在此基础上论述了沉积问断的存在,泥岩中有机质的丰度和干酪根类型是控制次生孔隙发育的主要因素。 相似文献
314.
复杂区域自适应三角形网格全自动生成方法 总被引:10,自引:4,他引:10
为了使用自适应有限单元法求解岩土工程问题,本文在行被法的基础上,提出了一种适用于多介质复杂区域的三角形网格全自动生成方法。文中给出三个工程算例. 相似文献
315.
试论轻烃形成过程中过渡金属的催化作用 总被引:16,自引:1,他引:16
轻烃和天然气是由富含干酪根矿物基质上过渡金属的催化作用形成,而不是干酪根和重质烃的热催化作用所致。催化作用是通过不同碳数闭作用,碳-碳及碳-金属键的断裂作用来实现的,它在轻烃形成的几个重要转化反应中起重作用,本文围绕着过渡金属的催化机理和轻烃的催化成因等基本问题展开经,目的在于不断探讨油气成因的新理论。 相似文献
316.
Zhao Yixin 《吉林大学学报(地球科学版)》1994,(4)
对老柞山金矿49件方解石样品的天然热发光曲线特征研究表明,成矿期方解石的热发光曲线以双峰为主要特征,成矿后期的方解石的热发光曲线则无峰型。方解石热发光曲线特征可作为矿区成矿阶段划分的一个重要标志。 相似文献
317.
The Jiyang Sag and the Liaohe Basin are the two important areas where immature oil resources are distributed in China. From
these two areas immature-low mature to mature oil samples were collected for carbon isotopic analysis. The extracts of source
rocks are dominant in the Jiyang Sag while crude oils are dominant in the Liaohe Basin. The maturity index, Ro, for source rocks varies from 0.25% (immature) to 0.65% (mature). Studies have shown that within this range of Ro values the extracts of source rocks and crude oils, as well as their fraction components, have experienced observable carbon
isotope fractionation. The carbon isotopic values tend to increase with burial depth, the oils become from immature-low mature
to mature, and the rules of evolution of oils show a three-stage evolution pattern, i. e., light→heavy→light→heavy oils. Such
variation trend seems to be related to the occurrence of two hydrocarbon-generating processes and the main hydrocarbon-forming
materials being correspondingly non-hydrocarbons and possessing MAB characteristics, lower thermodynamic effects and other
factors. In the process towards the mature stage, with increasing thermodynamic effects, the thermal degradation of kerogens
into oil has become the leading factor, and correspondingly the bond-breaking ratio of12C-13C also increases, making the relatively12C-rich materials at the low mature stage evolve again towards13C enrichment.
This research project was granted by both the 960006 Project of China Petroleum and Natural Gas Co. and the National Natural
Science Foundation of China (Grant No. 49973010). 相似文献
318.
Deterioration in the water quality results from coal mining, and the significant impact on the environment in South Africa
has been reported (Funke in SA Water, Sci Technol 15:115–144; 1983). Pyrite in with South African coal can be oxidised to
yield acidic and high salinity water. This study deals with the rate at which sulphate could be produced for collieries under
different conditions. Four collieries in the Witbank coalfield were selected for this investigation. The boreholes were investigated
with an in-situ multi-parameter probe, and then sampled at different times with a specific depth sampler to determine the
chemical composition of the water in the collieries. Water level measurements and volumetric calculations were done to determine
influx rates. Daily sulphate generation rate for underground mining was found to be in the range of 0.4–2.7 kg/ha, depending
on the availability of oxygen and the residence time of the water (the time available for neutralising agents present to react)
in the mining void. The exclusion of oxygen due to flooding and the presence of calcareous carbonates influences the observed
sulphate generation. 相似文献
319.
1INTRODUCTION SHALLOW(MOSTLYBIOGENIC)GASACCOUNTSFOROVER20%OFTHEWORLD’SDISCOVEREDGASRESERVES(RICEAND CLAYPOOL,1981;CLAYPOOLANDKAPLAN,1974),AND REPRESENTSONEOFTHEUNCONVENTIONALENERGYSOURCES THATINCREASINGLYATTRACTTHEATTENTIONOFPETROLEUMGEOL OGISTS.NUMEROUS… 相似文献
320.
详细考察了用氢化物发生-光导比色法在野外实验条件下测定Sb的各种条件及影响因素,制定了适合野外的氢化物发生-光导比色快速测定锑的方法。样品经王水封闭溶解后,在掩蔽剂存在下,用自制的硼氢化钾片使经预还原的Sb生成氢化物逸出,将吸收液中的Fe(Ⅲ)还原为Fe(Ⅱ)与邻菲口罗啉显色,用自行开发、研制的光导分光光度(比色)计进行比色测定。方法的检出限(3s)为0.18μg/g,加标回收率为96.0%~98.0%,11次测定的精密度(RSD)小于8.2%。方法经国家一级标准物质验证,分析结果与标准值吻合。 相似文献