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421.
西北太平洋热带气旋迅速增强特征及其影响因子   总被引:3,自引:1,他引:2  
选取西北太平洋上热带气旋(TC)24小时风速变化累积频率达95%所对应的15.4 m/s作为迅速增强(RI)的标准,研究了RI个例的基本特征以及TC自身特征因子与环境因子对RI的作用。结果表明,TC迅速增强过程的持续时间平均为33小时,最长可达78小时,并且TC经过迅速增强过程几乎都达到了台风级别以上,其中,一半以上达到了强台风级别以上。对比迅速增强(RI)和非迅速增强(non-RI)个例得到,RI个例相对于non-RI个例发生区域偏南偏东,两者的移动速度没有明显差异,但RI个例有较大向西移动分量并且前12小时增强较大;相对于non-RI个例,RI个例离最大潜在强度较远并且发生在较暖水区和55%~75%的低层相对湿度的条件下;RI个例发生在较小的垂直风切变和较弱的对流层上层东风气流情况下,由上层槽或冷低压引起的强迫弱于平均状况时RI较易发生。TC前12小时强度变化(DVMX)、海表面温度(SST)和垂直风切变(SHR)是影响迅速增强的主要因子,当DVMX≥6.3 m/s时RI发生的可能性最大,达到17.2%。当有若干个影响因子共同起作用时发生RI可能性显著增加,其中以较大的前12小时强度变化(DVMX≥6.3 m/s)、较高的海表面温度(SST≥29.4℃)、较弱的垂直风切变(SHR≤5.9 m/s)、较小的相对涡旋角动量通量辐合(REFC≤-1.6 m/(s.d))、偏东经度(LON≥138.2°E)和低纬度(LAT≤16.7°N)共同作用时,RI发生的可能性达到最大,可达66.7%。  相似文献   
422.
发展了一种能在野外测定0.25~1000μg/g银量的Ag-TMK-DBS三元络合物光导比色测定法。样品经硝酸封闭溶解后,用巯基棉富集分离银,在pH 4.5的乙酸-乙酸钠缓冲介质中,银与硫代米蚩酮(TMK)-十二烷基苯磺酸钠(DBS)形成易溶于水的红色三元胶束络合物,用自行开发研制的光导(比色)分光光度计比色测定痕量银。方法检出限为0.10μg/g,加标回收率为96.0%~99.4%,11次测定的精密度(RSD)小于5.76%。方法较为快速、简便、准确和灵敏,经国家一级标准物质验证,分析结果与标准值吻合。用光导分光光度计测定,准确度和精密度均有很大改进,结果与室内原子吸收光谱分析结果一致。方法具有广阔的应用前景。  相似文献   
423.
The purpose of this study is to do an experiment in finding conditions of search purification materials and the way of their proper processing for the rapid infiltration method. It seems that this result makes an index of further selection of a purification material. This experiment is to conduct sorption tests of fulvic acid and phosphoric acid regarding Kanuma-soil (volcanic ash soil) with iron oxide and aluminum oxide, to fred relationship between sorption coefficients and heating temperature, concentrations of iron and aluminum. The sorption experiment on heated and unheated materials was conducted at 25℃ in a dark place at the solid to liquid ratio of 1 : 2.5. The liquid is simulated river water. According to the result of the study, a deference was found of the best heating temperature between sorption coefficients of fulvic acid and phosphoric acid. The peak of a sorption coefficient of fulvic acid is 800℃, however the peak of a sorption coefficient of phosphoric acid is 400℃. In the case of fulvic acid, it is high sorption coefficients when Kanuma-soil with aluminum oxide is unheated and heated as 400℃. However, sorption coefficients when Kanuma-soil with iron oxide is not conspicuously different when heated, and coefficients are descended gradually more than 600℃. Sorption coefficients of unheated Kanuma-soil are descended when adding iron oxide. When heating temperature is higher, pH of water is higher. High pH causes to descend sorption coefficient, however it is remarkable result that sorption coefficient is ascended at 800℃. In the case of phosphoric acid, it is high sorption coefficient when Kanuma-soil is heated at 400℃, and Kanuma-soil with aluminum oxide is heated between 200℃ and 400℃. Sorption coefficients of Kanuma-soil with iron oxide are the highest when unheated, but sorption coefficients of Kanuma-soil with iron oxide are the highest when heated.  相似文献   
424.
回线源瞬变电磁测深快速反演方法   总被引:4,自引:3,他引:4  
回线源瞬变电磁测深法(简称瞬变电磁法或TEM法)是以不接地回线为场源,在回线内、外测量电磁场的一种电磁测深方法,已经广泛用于固体矿产、工程地质和水文地质调查工作之中[1,2]。目前,回线源瞬变电磁法主要采用中心回线和重叠回线两种测量装置,测量回线内垂直磁场产生的感应电动势。“烟圈”反演方法是瞬变电磁反演的主要计算方法,“烟圈”反演利用地表瞬变电磁响应与某时刻电流源镜像等效原理,计算勘探深度和对应电阻率。这里给出了回线源瞬变电磁测深一维“烟圈”反演解释方法的基本原理、计算方法和应用实例。结果表明,一维“烟圈”反演解释结果纵向分辨率较高,能反映出地下电性变化情况,可以用于瞬变电磁测深资料解释工作。  相似文献   
425.
对上海曲阳污水厂污泥及其快速堆肥产物中的Zn.Cu,Ni.Cd,Pb,Cr等六种重金属进行了含量及化学形态分析。分析结果表明堆肥过程不会改变污泥中各重金属元素的含量.堆肥前后重金属主要以稳定的形态存在,但堆肥过程进一步提高了重金属元素稳定形态的比例。变化最为显著的是污泥中含量较高的Zn,其不稳定形态的比例由37%降为16%.使得Zn的活性与毒性大大降低。经过快速堆肥.考察的六种重金属元素的稳定性得到了提高,减小了污泥土地利用时重金属的环境危害。  相似文献   
426.
In rural Burkina Faso, intensification has been an uneven process that has resulted in social costs, particularly in the form of uneven distribution of assets and disparate environmental trade-offs. This study examines the effects of wealth status on agricultural practice and soil fertility, arguing that differences in the practices of wealthier and poorer farmers lead to differential social and environmental outcomes. Two concerns are highlighted. First is the role of poverty in environmental degradation. Much of the debate about the role of wealth and poverty in environmental outcomes in developing countries has pinpointed poverty as the main causal explanation. Using studies of agricultural practices and soil fertility from several villages in southwestern Burkina Faso, this paper will counter this dominant view by showing that wealthier farmers farm much larger areas, have fewer trees in their fields, and use higher levels of animal traction which, in turn, has led to lower levels of soil fertility. A second concern is that while poorer farmers may have agricultural practices that minimize environmental degradation, their exclusion from key institutions that provide access to resources has serious livelihood consequences and potentials for increasing socioeconomic differentiation. The agricultural practices of wealthier farmers, while not optimal environmentally, result in higher levels of household wealth. A paradox emerges that while poorer farmers are conserving environmental resources, they are doing so at the expense of economic development and well-being.  相似文献   
427.
Debris flows in the Gleivarhjalli area in northwestern Iceland occurred after a sudden and intensive snowmelt period during 10–12 June, 1999. The area, in the northwestern part of the town of Ísafjörvur, was chosen for a detailed study. Meteorological data and bedrock conditions, triggering mechanisms and geomorphological and human impacts were examined. This paper describes and emphasises the role of rapid snowmelt as a mechanism for the release of debris flows in a subpolar basaltic fjord setting. Post‐event mapping of erosional and depositional landforms showed strong geomorphic impacts of debris flows and their role in mass transfer in a mountainous environment. The estimated denudation rate for the singleevent is 0.29 mm/km2. The use of a new lichen growth curve provides relative dating of previous unreported events. Finally, the paper estimates the mean return period for debris‐flow events in the Gleivarhjalli area as 4–5 years, thus constituting a serious threat to the community.  相似文献   
428.
Based on the analyses of generation, migration and accumulation of oil and gas in the structures of Kela 1, Kela 2 and Kela 3 in Kasangtuokai anticlinal belt using a series of geological and geochemical evidence, this paper proposes that the rapid rate of hydrocarbon generation, main drain path for over-pressured fluid flow and converging conduit system are indispensable conditions for the rapid, late-stage gas accumulation in the Kelasu thrust belt in the Kuqa depression. Due to structural over-lapping and the resultant rapid burial, the maturity of the source rocks had been increased rapidly from 1.3 to 2.5% Ro within 2.3 Ma, with an average rate of Ro increase up to 0.539% Ro/Ma. The rapid matura-tion of the source rocks had provided sufficient gases for late-stage gas accumulation. The kelasu structural belt has a variety of faults, but only the fault that related with fault propagation fold and cut through the gypsiferous mudstone cap could act as the main path for overpressured fluid release and then for fast gas accumulation in low fluid potential area. All the evidence from surface structure map, seismic profile explanation, authigenic kaolinite and reservoir property demonstrates that the main drain path related with faults for overpressured fluid and the converging conduit system are the key point for the formation of the giant Kela 2 gas field. By contrast, the Kela 1 and Kela 3 structures lo-cated on both sides of Kela 2 structure, are not favourable for gas accumulation due to lacking con-verging conduit system.  相似文献   
429.
介绍了利用视频技术检测激光束牛顿环中心的方法,为准直应用提供了参考。实验表明,快速Hough变换可以获取理想的检测结果。  相似文献   
430.
华南近海急剧加强热带气旋及其环流综合分析   总被引:9,自引:1,他引:9  
林良勋  梁巧倩  黄忠 《气象》2006,32(2):14-18
在给出近海急剧加强热带气旋定义的基础上,对1949~2004年在华南近海急剧加强的46个热带气旋的区域和源地、路径和强度、风雨分布等进行分析,得到一些有意义的统计事实。综合分析还发现:热带气旋近海急剧加强主要发生在东高西低、北高南低和弱背景环流中;不同的环境背景下,西南季风、越赤道气流、东风波、弱冷空气、西风槽是诱发近海急剧加强的主要系统。  相似文献   
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