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51.
针对油气勘探中存在的油水关系复杂问题,采用油气藏解剖和油气分布与成藏条件之间的空间匹配关系,对齐家—鸳鸯沟地区沙河街组油气富集规律及控制因素进行了研究,结果表明:齐家—鸳鸯沟地区油气在纵向上主要分布在沙二段,平面上主要分布在Ⅲ号台阶上,并以断层-岩性油气藏类型居多;油气富集主要受到砂体储层是否发育、圈闭是否发育、断层侧向封闭性强弱、断裂后期活动性强弱4个因素的控制;不同层段油气富集的主控因素不同,沙二段、沙三1亚段和沙四段圈闭不发育是造成失利井的最主要原因,而沙三2亚段和沙三3亚段砂体储层不发育也是造成失利井的最主要原因。 相似文献
52.
根据短壁开采条件下保护煤柱的布设特点,建立由保护煤柱支承的关键层力学分析模型。针对不同采场设计参数进行关键层受力及变形的弹性和黏弹性分析,得到弹性介质关键层下沉量的理论计算式,及黏弹性介质关键层变形随时间变化的表达式。评价不同采场参数对关键层随时间变形的影响,给出理想的建筑物下短壁开采设计参数范围,为“三下”开采设计和长期地表沉陷预计提供理论依据。 相似文献
53.
工程上常见几何体体积计算 总被引:1,自引:0,他引:1
阐述了工程上常见几何体体积准确计算公式、近似计算公式及误差计算式,指出工程上常用算法中存在的问题,最后推荐一种精度较高的近似算法。 相似文献
54.
Effects of manganese doping on properties of sol-gel derived biphasic calcium phosphate ceramics 总被引:1,自引:0,他引:1
We have investigated the effect of manganese (Mn) doping on properties of nanosized biphasic calcium phosphate powders and their dense bodies. Manganese levels of 0.6, 1.3, 1.9, 4.3, 7.0 and 11.9 at.% were successfully incorporated into biphasic calcium phosphate via a sol-gel route. The prepared powders were calcined at temperatures of 500-1200 °C. The X-ray diffraction analysis revealed that a mix phase comprising of hydroxyapatite and β-tricalcium phosphate were present, however the content of each phases in the structure was affected by the Mn content. The studies found that the largest portion of β-tricalcium phosphate was detected at 4.3 at.% Mn doping. The incorporation of Mn has also greatly increased the crystallinity of the biphasic calcium phosphate powder due to progressive densification of particles. Characterization on their sintered dense bodies showed that manganese concentration affected the physical properties of the dense bodies. The highest density was found for 4.3 at.% Mn doped biphasic calcium phosphate sintered at 1300 °C. 相似文献
55.
Wenke Weidemann Jessica Hering Dorit Bennmann Annett Thate Rüdiger Horstkorte 《International journal of molecular sciences》2013,14(10):20555-20563
The bi-functional enzyme UDP-N-acetyl-2-epimerase/N-acetylmannosamine kinase (GNE) is the key enzyme of the sialic acid biosynthesis. Sialic acids are negatively charged nine carbon amino sugars and are found on most glycoproteins and many glycolipids in terminal positions, where they are involved in a variety of biological important molecular interactions. Inactivation of the GNE by homologous recombination results in early embryonic lethality in mice. Here, we report that GNE-deficient embryonic stem cells express less differentiation markers compared to wild-type embryonic stem cells. As a result, GNE-deficient embryonic stem cells fail to form proper embryoid bodies (EB) within the first day of culture. However, when culturing these cells in the presence of sialic acids for three days, also GNE-deficient embryonic stem cells form normal EBs. In contrast, when culturing these cells in sialic acid reduced medium, GNE-deficient embryonic stem cells proliferate faster and form larger EBs without any change in the expression of markers of the germ layers. 相似文献
56.
57.
分析了萘磺化反应体系中硫酸含量与萘磺化反应进程的关系,提出以酸碱滴定法测定体系中硫酸含量来精确分析磺化反应进程的方法。 相似文献
58.
Albert Falques 《热应力杂志》2013,36(2):145-160
The thermodynamical foundations of generalized thermoelasticity formulated by Lord and Shulman are reviewed and memory effects on the heat flux are generalized. An existence and uniqueness theorem for the evolution integro-differential equations is obtained using semi-group theory. 相似文献
59.
Interactive rigid body simulation is an important part of many modern computer tools, which no authoring tool nor game engine can do without. Such high‐performance computer tools open up new possibilities for changing how designers, engineers, modelers and animators work with their design problems. This paper is a self contained state‐of‐the‐art report on the physics, the models, the numerical methods and the algorithms used in interactive rigid body simulation all of which have evolved and matured over the past 20 years. Furthermore, the paper communicates the mathematical and theoretical details in a pedagogical manner. This paper is not only a stake in the sand on what has been done, it also seeks to give the reader deeper insights to help guide their future research. 相似文献
60.