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971.
本文在分析了岩体系统的结构性和水力学特征后,提出了岩体渗流场与应力场耦合数学模型的机理分析、混合分析及系统辨识建模方法。运用系统辨识方法建立了岩体渗流场与应力场耦合的集中参数模型,并应用于解决实际问题;运用机理分析和混合分析方法建立了岩体渗流场与应力场双场耦合及与温度场三场耦合的连续介质分布参数模型。  相似文献   
972.
本文依据宝鸡岩体颜家河超单元各单元的岩石组构、矿物成分、岩石化学和地球化学等方面的资料,研究了它们由早到晚的变化特征,并将各种特征有机地联系在一起,发现该超单元岩浆从早到晚存在着反序演化的特点,即由偏酸性岩浆向偏基性岩浆演化,并建立了该超单元的岩浆演化模式。  相似文献   
973.
本文利用扫描隧道显微镜(STM)对辉锑锡铅矿{100}解理面的表面结构特征进行了研究,得到了清晰的原子级分辨率图像,并观察到辉锑锡铅矿结构中因两种基本构造层不匹配而导致的调制波结构及超结构长周期现象。同时还观测研究了辉锑锡铅矿的表面微形貌特征。  相似文献   
974.
IntroductionSolutionasakarstgeomorphologicalprocessinlandformdevelopmenthaslongbeenrecognized.Sincethekarstprocessesarealmostentirelysolution,thoughkarstlandformsarenotonlycausedbysolutionbutalsobyerosion,thecirculationandchemicalcompositionsofkarstun…  相似文献   
975.
I.LandDegradationDistributionandItsCharacteristicsThefarmingpastoraltransitionalregioninsemiaridlandofnorthernChinaisthemosttypicalregionoflanddegradation,andalsotheregionwithextensivelydevelopingsandydesertification.TheextentisfromHorqinSandyLandinth…  相似文献   
976.
Discovery process modeling has gained wide acceptance in the Chinese exploration community. In recent years, a variety of discovery process models have been applied to the prediction of undiscovered petroleum resources at the play level in sedimentary basins in China. However, challenging problems have been encountered, particularly when one method alone has been applied to small plays in nonmarine sedimentary basins or in plays with an unusual order of discovery wells. This paper presents results gotten by using the lognormal discovery process model of the Geological Survey of Canada and the geoanchored method for three petroleum plays in basins with different geologic settings. Although the predicted shapes of the parentsize distributions which use these two models, were not always similar, the expected values of the total resources and the number of fields (pools) to be discovered are comparable. The combined use of two discovery process models in the same play compensates for the weaknesses in one method compared with the other and vice versa. Thus, more reliable estimates are the result.  相似文献   
977.
Invertebrate colonization of lakes following the uplift of land from the sea was studied in four lakes, currently situated between 39 and 24 m a.s.l., on the central Norwegian coast. The lakes were isolated from the sea between 9500 and 7700 years B.P. Animal and algal remains picked from core samples showed that the first colonizers preserved as fossils were usually members of the Chironomidae, Daphnidae/Chydoridae, Acarina, Porifera (Ephydatia mülleri and Spongilla lacustris), Bryozoa (Cristatella mucedo and Plumatella spp.) and Charophyta (Chara sp.). Of the chironomids, the genus Chironomus was present in the oldest lacustrine layers of all four lakes, but other genera recorded at the marine/lacustrine boundary were Dicrotendipes, Procladius (?), Einfeldia, Microtendipes, and Glyptotendipes. Remains of the caddis fly family Limnephilidae were also present in the earliest lacustrine sediments in Kvennavatnet and Kvernavatnet. The oldest invertebrate fauna is typical for mesotrophic lakes. However, chironomids and mites have been present in this area from at least about 10?500 years B.P. A diverse chironomid community was established between 300 and 800 years after isolation from the sea at Kvernavatnet on the island of Hitra, while only between 80 and 120 years passed before a comparably diverse community developed at Kvennavatnet on the mainland coast. A similar development of the invertebrate fauna occurred in Kvennavatnet, Kvernavatnet and Storkuvatnet. However, Litjvatnet deviates greatly from the ‘normal’ pattern because a tsunami disturbed the bottom sediments and fauna. The tsunami, a gigantic sea wave, was caused by a submarine slide from the Norwegian continental slope. It reached Litjvatnet, today located 24 m a.s.l., but was not traced in Storkuvatnet at 30 m a.s.l. This event happened about 7200 years B.P.  相似文献   
978.
The ability of seismological criteria to identify earthquakes from underground explosions depends partly on the orientation of the earthquake source. Well-determined double-couple moment tensor solutions for a large number of earthquakes have been published in the Harvard centroid moment tensor (CMT) and United Slates Geological Survey (USGS) catalogues. Statistical analyses of these catalogues indicate that the distribution of the orientation of earthquake mechanisms is not random. The distribution of the T axes shows significant clustering around the downward vertical, indicating that a larger number of earthquake mechanisms radiate compressional P -wave energy to teleseismic distances from near the maximum of the radiation pattern than is predicted if earthquake sources are randomly oriented double couples. The clustered T axes correspond to compressional dip-slip mechanisms, and it is this type of mechanism which is believed to cause both the m b: M s (the ratio of body-wave to surface-wave magnitude) and first-motion criteria to misidentify an earthquake as an explosion.  相似文献   
979.
黎夏  叶嘉安 《地理研究》1997,16(4):56-62
伴随着经济的快速增长,珠江三角洲近年来出现了迅速的城市化以及乡村城市化的过程。沿着城镇边缘和公路两旁,大片的农田被侵占来单方面地满足城市开发的需要,忽略了粮食产量减少以及环境质量恶化等问题。利用遥感可以有效地监测珠江三角洲的城市扩张过程。在遥感多时相监测的基础上通过熵的计算,可以定量地描述城市扩张的空间规律及扩散过程。  相似文献   
980.
灰色预测模型在径流长期预报中的应用   总被引:6,自引:3,他引:6  
基于灰色系统的建模理论,利用河西地区有关河流的径流观测资料,建立了一个GM(1,1)残差序列周期修正径流预测模型,并用于春旱缺水期3~6月河流来水量的长期预报,经生产部门验证,准确率在80%以上  相似文献   
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