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51.
内蒙古科尔沁右翼中旗孟恩陶勒盖岩体年代学研究 总被引:1,自引:0,他引:1
对内蒙古科尔沁右翼中旗地区孟恩陶勒盖岩体进行了LA-ICP-MS锆石U-Pb同位素年代学研究.结果表明,孟恩陶勒盖岩体形成年龄为(224±1)Ma,表明该岩体是在中三叠世侵位的.结合区域地质资料和前人相关研究,推测该区中三叠世花岗岩可能是古亚洲洋闭合碰撞时岩石圈挤压机制下的产物,该结果为华北板块与西伯利亚板块碰撞时限提供了新的年代学资料. 相似文献
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低渗透油藏受层间储层物性差异的影响,层间动用程度差异大,层间矛盾突出。层间径向钻孔技术是解决层间矛盾的重要技术之一。依据层间均衡驱替的原则,考虑启动压力梯度,应用等值渗流阻力法,建立了径向钻孔长度及分支个数的优化模型,并提出了现场实用的交会图版求解方法。利用油藏数值模拟技术,对优化方法进行了验证,证实了此方法的可行性与准确性。 相似文献
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针对自适应机翼飞行器设计了一种翼身连动机构,使机翼能够完成变前后掠、变翼展、变上下反角三种变形,从而在整个飞行任务过程中都能使飞行器达到气动性能最优。该连动机构以经典3—RPS并联机构为原型,通过3杆联动完成机翼姿态的变化。根据自适应机翼的变形要求,该结构对经典3—RPS机构进行改进,使机构在单一转动自由度和平动自由度的复合运动中,不会产生衍生自由度。且新结构截面外形与机翼截面的几何构型更为接近,较之经典3—RPS机构更适合应用于自适应机翼的连动机构。此外,电控系统设计也更利于系统未来优化升级。 相似文献
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赵晓阳 《河北省科学院学报》2017,34(1):44-49
介绍了一种简易标定数字近景摄影测量系统中基准尺实际长度的方法。即以检定合格的游标卡尺作为尺寸基准,利用游标卡尺拨动长度与基准尺长度的比例关系,来计算基准尺实际长度。实验结果表明,使用该方法标定具有速度快、精度高、成本低的优点,非常适合车间内基准尺长度标定。 相似文献
56.
《Journal of Natural History》2012,46(5):773-791
Patterns of postnatal growth, and changes in mass and wing loading during reproduction were studied in captive free-flying brown long-eared bats (Plecotus auritus, Linnaeus, 1758). The bats were fed on noctuid moths occasionally supplemented with mealworms. Growth in body mass was best described by the von Bertalanffy model (n = 5 individuals), while growth in forearm length, wingspan and wing area, were best described by the logistic equation (n = 5 individuals). Because the wings developed more rapidly than body mass, wing loading decreased from high levels following birth to a minimum at around 30 days of age. Predicted mechanical power requirements for flight (minimum power Pmp and maximum range power Pmr) and the corresponding flight speeds (Vmp and Vmr) as well as the minimum theoretical radius of a banked turn (rmin) also reached minima at this time. At 30 days of age juveniles could fly with lower predicted power requirements and were more manoeuvrable (could fly more slowly at minimum power and make tighter turns) than adults. These minima corresponded to the time when juveniles first left the roost box to fly. Reproductive females (n = 6) displayed a near two-fold increase in body mass and wing loading over 50 days prior to birth. This resulted in a three-fold increase in the predicted mechanical power requirements for flight (Pmp and Pmr), and a decrease in predicted flight manoeuvrability. Non-reproductive individuals (n = 22) had a similar pattern but increased in body mass and wing loading to a lesser extent. Over days 1 to 40 postpartum, both mass and wing loading declined in lactating females, but continued to increase in the non-reproductive bats. 相似文献
57.
《Journal of Natural History》2012,46(6):673-679
Significant positive correlation between wing length and scale length was found in a broad sample of lepidopteran taxa. No breakdown of the correlation was observed in the lowest wing size range. The best fit is a non-linear (power) curve. The minimum individual scale length observed was 40 µm (in a nepticulid), while the maximum was close to 500 µm (in a castniid; there are literature records of even larger scales in this family). Scale size variation probably reflects variation in the size of scale-forming trichogen cells. The latter, in turn, may at least partly reflect difference in genome size, such as has long been known to be the case with the cells that form, respectively, the cover and ground scales in some higher moths. 相似文献
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陈文俊 《系统工程与电子技术》1998,(8)
在MSC/NASTRAN气动弹性分析用户指南68版中,提供了一气动热弹性考题HA15-3A。按照该考题的计算结果,150(相当于65.5℃)时的颤振速度约为零度时的三分之一。这么大的温度效应似乎令人难以置信。为此,本文对该考题计算结果进行了分析和探讨。最后,作者认为,上述计算结果尽管是特殊的或偶然的,但它并非是不可能的。 相似文献