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71.
研究了连续变量函数的全局最优化问题 ,给出了动态隧道方法。该动态隧道方法由局部搜索和动态隧道 2个阶段构成。在局部搜索阶段用了动态系统方法。对全局最优化问题的实例进行了数值实验 ,数值结果表明了该方法的稳健性和有效性。  相似文献   
72.
本文根据动画地图表示内容和常用动画技术的特点,对二维动画地图的表示方法进行了探讨。归纳了基于空间分布特征的表示方法、基于动画地图用途的表示方法和基于动画技术的表示方法及其分类,并讨论了影响选择表示方法的因素和几种表示方法相互配合的应用规律,对动画地图可视化的理论与技术的研究有一定参考。  相似文献   
73.
水平井含水率上升影响因素   总被引:1,自引:1,他引:0  
利用塔里木油田塔中4油田(TZ4)底水油藏相关的地质、流体数据建立数值模型。在所建模型的基础上,应用数值模拟计算的累积产油、产水和产液量回归俞启泰水驱特征曲线,以反映水平井见水特征的参数b。以参数b为研究对象,采用正交试验的方法研究不同因素对b值的影响,筛选影响水平井见水特征的主要因素,认为原油粘度、油层厚度、非均质性及水平井水平段在油藏中的位置是影响水平井含水上升趋势的主要指标。最后建立主要因素与b值的关系式,结合俞启泰曲线b值图版,提出预测水平井见水规律的公式——图版法(F-b法)。应用F-b法对塔里木水平井含水率进行预测,并与其他相关方法及实际生产数据对比,认为F-b法可作为预测塔里木油田水平井含水率、估算可采储量的一种有效方法。  相似文献   
74.
Based on the theory of formation dynamics of oil/gas pools, the Dongying sag can be divided into three dynamic systems regarding the accumulation of oil and gas: the superpressure closed system, the semi-closed system and the normal pressure open system. Based on the analysis of genesis of superpressure in the superpressure closed system and the rule of hydrocarbon expulsion, it is found that hydrocarbon generation is related to superpressure, which is the main driving factor of hydrocarbon migration. Micro fractures formed by superpressure are the main channels for hydrocarbon migration. There are three dynamic patterns for hydrocarbon expulsion: free water drainage, hydrocarbon accumulation and drainage through micro fissures. In the superpressure closed system, the oil-driving-water process and oil/gas accumulation were completed in lithologic traps by way of such two dynamic patterns as episodic evolution of superpressure systems and episodic pressure release of faults. The oil-bearing capacity of lithologic traps is intimately related to reservoir-forming dynamic force. Quantitative evaluation of dynamic conditions for pool formation can effectively predict the oil-bearing capability of traps.  相似文献   
75.
土钉抗拔承载力的原位试验研究   总被引:1,自引:0,他引:1       下载免费PDF全文
陆益成  薛艳 《江苏地质》2008,32(2):133-136
根据土钉现场抗拔试验数据,分析了钉材、浆液龄期等因素对土钉抗拔承载力的影响,建议了合理的下层土钉开挖时间。最后通过试验土钉抗拔力反算土体与锚固体的极限粘结强度,并与规范推荐值进行了比较。  相似文献   
76.
介绍了利用ArcObjects开发、基于ArcScene的建筑物日照分析模块的研制,对各个子模块作了介绍。特别对涉及到的日照分析技术、阴影动态显示、3维建筑设计等技术做了详细的说明。最后对该模块的应用做了简要演示。  相似文献   
77.
GM(1,1)动态模型在吴江市地下水水位预测中的应用   总被引:1,自引:0,他引:1  
以吴江市地下水水位预测为例,详细阐述了地下水水位时间序列的GM(1,1)动态模型的原理和建立过程,并根据模型的预测值和实测值,对模型的精度进行了检验,结果表明,模型的预测精度达到了99.27%,等级属于Ⅰ级,具有实际的应用价值,为地下水资源的科学管理提供了依据。  相似文献   
78.
Rare earth elements (REE) have been mined in North America since 1885, when placer monazite was produced in the southeast USA. Since the 1960s, however, most North American REE have come from a carbonatite deposit at Mountain Pass, California, and most of the world’s REE came from this source between 1965 and 1995. After 1998, Mountain Pass REE sales declined substantially due to competition from China and to environmental constraints. REE are presently not mined at Mountain Pass, and shipments were made from stockpiles in recent years. Chevron Mining, however, restarted extraction of selected REE at Mountain Pass in 2007. In 1987, Mountain Pass reserves were calculated at 29 Mt of ore with 8.9% rare earth oxide based on a 5% cut‐off grade. Current reserves are in excess of 20 Mt at similar grade. The ore mineral is bastnasite, and the ore has high light REE/heavy REE (LREE/HREE). The carbonatite is a moderately dipping, tabular 1.4‐Ga intrusive body associated with ultrapotassic alkaline plutons of similar age. The chemistry and ultrapotassic alkaline association of the Mountain Pass deposit suggest a different source than that of most other carbonatites. Elsewhere in the western USA, carbonatites have been proposed as possible REE sources. Large but low‐grade LREE resources are in carbonatite in Colorado and Wyoming. Carbonatite complexes in Canada contain only minor REE resources. Other types of hard‐rock REE deposits in the USA include small iron‐REE deposits in Missouri and New York, and vein deposits in Idaho. Phosphorite and fluorite deposits in the USA also contain minor REE resources. The most recently discovered REE deposit in North America is the Hoidas Lake vein deposit, Saskatchewan, a small but incompletely evaluated resource. Neogene North American placer monazite resources, both marine and continental, are small or in environmentally sensitive areas, and thus unlikely to be mined. Paleoplacer deposits also contain minor resources. Possible future uranium mining of Precambrian conglomerates in the Elliott Lake–Blind River district, Canada, could yield by‐product HREE and Y. REE deposits occur in peralkaline syenitic and granitic rocks in several places in North America. These deposits are typically enriched in HREE, Y, and Zr. Some also have associated Be, Nb, and Ta. The largest such deposits are at Thor Lake and Strange Lake in Canada. A eudialyte syenite deposit at Pajarito Mountain in New Mexico is also probably large, but of lower grade. Similar deposits occur at Kipawa Lake and Lackner Lake in Canada. Future uses of some REE commodities are expected to increase, and growth is likely for REE in new technologies. World reserves, however, are probably sufficient to meet international demand for most REE commodities well into the 21st century. Recent experience shows that Chinese producers are capable of large amounts of REE production, keeping prices low. Most refined REE prices are now at approximately 50% of the 1980s price levels, but there has been recent upward price movement for some REE compounds following Chinese restriction of exports. Because of its grade, size, and relatively simple metallurgy, the Mountain Pass deposit remains North America’s best source of LREE. The future of REE production at Mountain Pass is mostly dependent on REE price levels and on domestic REE marketing potential. The development of new REE deposits in North America is unlikely in the near future. Undeveloped deposits with the most potential are probably large, low‐grade deposits in peralkaline igneous rocks. Competition with established Chinese HREE and Y sources and a developing Australian deposit will be a factor.  相似文献   
79.
Changes in hydrogeological properties of the River Choushui alluvial fan aquifer before and after the 1999 Chi-Chi earthquake, Taiwan, have been identified using pumping tests. Three wells, SH2, YL2 and SC2, located in a compressional zone with high coseismic groundwater levels, were tested. The threshold of the aquifer deformation with respect to transmissivity (T) is greater than that with respect to storage coefficient (S). Decreases in the post-earthquake S are approximately 60% at SH2 and SC2, indicating aquifer compression after the Chi-Chi earthquake. Changes in the post-earthquake T range from 61% increase to 0.8% decrease. Moreover, results from anisotropy analysis of T at SC2 further illustrate that normal stresses induced by the Chi-Chi earthquake have consolidated soil particles. Soil particles dilated laterally after the earthquake, resulting in an increase of the equivalent T. The changes in hydrogeological properties have a considerable influence on spatiotemporal fluid pressure and horizontal groundwater movement, resulting in different amounts of drawdown during post-earthquake pumping.  相似文献   
80.
We introduce and propose zircon M257 as a future reference material for the determination of zircon U‐Pb ages by means of secondary ion mass spectrometry. This light brownish, flawless, cut gemstone specimen from Sri Lanka weighed 5.14 g (25.7 carats). Zircon M257 has TIMS‐determined, mean isotopic ratios (2s uncertainties) of 0.09100 ± 0.00003 for 206pb/238U and 0.7392 ± 0.0003 for 207pb/235U. Its 206pb/238U age is 561.3 ± 0.3 Ma (unweighted mean, uncertainty quoted at the 95% confidence level); the U‐Pb system is concordant within uncertainty of decay constants. Zircon M257 contains ~ 840 μg g?1 U (Th/U ~ 0.27). The material exhibits remarkably low heterogeneity, with a virtual absence of any internal textures even in cathodoluminescence images. The uniform, moderate degree of radiation damage (estimated from the expansion of unit‐cell parameters, broadening of Raman spectral parameters and density) corresponds well, within the “Sri Lankan trends”, with actinide concentrations, U‐Pb age, and the calculated alpha fluence of 1.66 × 1018 g?1. This, and a (U+Th)/He age of 419 ± 9 Ma (2s), enables us to exclude any unusual thermal history or heat treatment, which could potentially have affected the retention of radiogenic Pb. The oxygen isotope ratio of this zircon is 13.9%o VSMOW suggesting a metamorphic genesis in a marble or calc‐silicate skarn.  相似文献   
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