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81.
通过大量的实验分析,揭示了Coniopteris simplex的原位孢子特征,甘肃窑街盆地中侏罗世Coniopteris simplex 原位孢子的基本特征可以概括为:孢子为四面体形,极面观为三角形至圆三角形,顶角钝圆,三边线内凹; 体积小,极面观直径为25~38 μm,平均约30 μm; 三射线平直或微弯,其长度为半径的2/3~3/4,宽度较窄,具唇状边缘。外壁近于光滑,但具多条不规则的褶皱; 无周壁; 孢子的颜色以黄褐色为主。明确了Cyathidites minor可能是Coniopteris simplex孢子,后者为前者的母体植物。 相似文献
82.
In situ infiltration test using a reclaimed abandoned river bed: managed aquifer recharge in Shijiazhuang City,China 总被引:3,自引:1,他引:3
Managed aquifer recharge (MAR) is necessary for water resources management in arid and semiarid regions. Infiltration rate is often a decisive limiting factor in site selection for MAR. In order to avoid scale effects in the application of infiltration rate parameters, the largest in situ infiltration test in China was undertaken between August 19 and August 30, 2009 to measure the infiltration rate of the field selected for MAR in Shijiazhuang City, China. The in situ test lasted for 10 days, and about 1.82 × 107 m3 of water was introduced into the infiltration field. Groundwater level variations were monitored during the test. Monitoring showed that the infiltration rate of surface water was 1.5 m/day, which means that about 10–15 × 108 m3/a of water could be injected into the target aquifer. Also, groundwater level variations showed that the northern part of the infiltration field had a higher infiltration rate, as predicted, and the test result supplied a sound foundation for validation of the groundwater numerical simulation, which will be of benefit for future predictions of the response of the groundwater level to artificial recharge engineering. Finally, an artificial recharge plan was proposed based on the infiltration test results and the water source conditions, which would be useful for the development of MAR programs and management of local water resources. 相似文献
83.
为了更好地研究神狐海域试采区天然气水合物的展布形态和赋存状况,基于高精度层析速度反演后的叠前深度偏移地震资料进行AVO反演技术研究。为在天然气水合物富集区有效地进行AVO研究,AVO处理前运用叠前深度偏移技术,通过高精度层析反演不断迭代速度模型;然后通过偏移来改善资料的质量,结合实测钻井资料进行AVO正演分析、反演可行性分析、属性交会分析;最后将具有高横向分辨能力的地震资料和高垂向分辨能力的测井资料与地质相结合进行叠前同时反演。该方法可反演出纵、横波阻抗等属性,直接进行岩性和流体识别,结果表明,在AVO反演中引入叠前深度偏移技术,为反演提供了较高质量的叠前共反射点道集和精细的层速度模型,改善了AVO技术在试采区的应用效果,提高了反演的可靠性。反演出的各种属性为AVO分析提供了丰富的信息,能够比较准确地反映地下水合物矿体的展布情况,可用于后续水合物储层的分析及综合研究,对未来的水合物勘探开采具有重要的现实意义。 相似文献
84.
An attempt to resolve non-uniqueness in the interpretation of transient electromagnetic (TEM) sounding data using measured data alone is made. It is shown in the various examples studied that sufficiently early time measurements can be the determining factor in reducing the ambiguity caused by model equivalence. The early delay times thus play a dual role in transient soundings: they are responsible for resolving shallow structures and they may eliminate the ambiguity in the interpretation of geoelectric parameters of deeper targets. This is illustrated by the results of a follow-up TEM survey at the Dead Sea coast of Israel where the use of supplementary early time measurements allowed non-uniqueness in the determination of the depth to fresh/saline groundwater interface to be resolved. 相似文献
85.
Taking advantage of the relation of lateral Lagrangian time scale TLY with the stability and height,we establish a three-dimensional random dispersion model and simulate the dispersing process of a ground source within the surface layer.The results calculated show that under the condition of stable stratification our model is obviously better improved than those obtained by assuming TLY to be constant,while under unstable condition,not much improved. 相似文献
86.
This paper briefly reviews several large-scale modeling systems for nuclear power plant accidents in the United States, and
summarizes our recent modeling results for the effects of key meteorological conditions, radioactive release characteristics,
and evacuation strategies on radiation doses. This work was intended to be useful in the formulation of emergency plans for
nuclear power plant accidents. The sensitivity analyses establish a scale for comparing impacts at various locations and over
time depending on the variation of those key parameters, and have clear implications for emergency planning. 相似文献
87.
A swallow-tail type catastrophic model of earthquake process 总被引:1,自引:0,他引:1
(殷有泉)(杜静)Aswallow-tailtypecatastrophicmodelofearthquakeprocess¥You-QuanYINandJingDU(PekingUniversdy,Beijing100871,China)(Nort... 相似文献
88.
89.
1 IntroductionEnvironmental decision support systems could be divided into two categories by their organizational form and system functions. One is regional environmental analytical system based on commercial GIS and assisted by environmental models, such as BASINS developed by the American NEPA using ARC/VIEW as its user platform and including QUAL2E and NPSM as its prediction tools. The other is environmental information and prediction system based on mathematical models, such as… 相似文献
90.
改进的Prim算法在GIS中的应用 总被引:3,自引:0,他引:3
探讨了数字常平基础信息平台建设项目中构建一个低造价通信网的问题,建立了网络模型和相应的存储结构,采用优化的Prim算法实现了这颗最小生成树。 相似文献