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本文对用凝胶封堵高渗层效果做了模拟研究,所选模型是由两个独立的均质层组成,每层渗透率在纵向上均是各向同性。层间水平渗透率比为0.0033-0.5,两层的垂直/水平渗透率比相同且为0.001-0.1。先将凝胶注入到高渗透的深层中,再在每层中注入聚合物和水,每层流度不同,注入到各层中的量亦不同,由于改善了注入剖面,从而降低了垂直/水平渗透率比,所以在井筒附近用凝胶封堵高渗层可提高原油采收率。相同条件下 相似文献
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本文阐述国际放射防护委员会所采用辐射致部危险度和组织权重因子的改变。着重介绍ICRP1990年建议书中有关辐射危害的估算方法,在总危害中不仅考虑到辐射诱发致死癌症的概率,还考虑辐射诱发非致死癌症的概率,在受照者所有后代产生的严重遗传疾患的概率,以及这些有害作用所致的预期寿命损失。 相似文献
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本文运用不可调参数建立了一个关于复合水气交替注入驱油中粘性指进问题的预测模型。利用该模型可生成一个可应用在常规复合模拟程序中的拟函数,且已成功地运用在三种类型实例中,包括一个简单的非均质油藏。 相似文献
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Wang JW Wu HN Li HX 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2012,42(3):927-938
In this paper, a distributed fuzzy control design based on Proportional-spatial Derivative (P-sD) is proposed for the exponential stabilization of a class of nonlinear spatially distributed systems described by parabolic partial differential equations (PDEs). Initially, a Takagi-Sugeno (T-S) fuzzy parabolic PDE model is proposed to accurately represent the nonlinear parabolic PDE system. Then, based on the T-S fuzzy PDE model, a novel distributed fuzzy P-sD state feedback controller is developed by combining the PDE theory and the Lyapunov technique, such that the closed-loop PDE system is exponentially stable with a given decay rate. The sufficient condition on the existence of an exponentially stabilizing fuzzy controller is given in terms of a set of spatial differential linear matrix inequalities (SDLMIs). A recursive algorithm based on the finite-difference approximation and the linear matrix inequality (LMI) techniques is also provided to solve these SDLMIs. Finally, the developed design methodology is successfully applied to the feedback control of the Fitz-Hugh-Nagumo equation. 相似文献
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Pollock B Burton M Kelly JW Gilbert S Winer E 《IEEE transactions on visualization and computer graphics》2012,18(4):581-588
Stereoscopic depth cues improve depth perception and increase immersion within virtual environments (VEs). However, improper display of these cues can distort perceived distances and directions. Consider a multi-user VE, where all users view identical stereoscopic images regardless of physical location. In this scenario, cues are typically customized for one "leader" equipped with a head-tracking device. This user stands at the center of projection (CoP) and all other users ("followers") view the scene from other locations and receive improper depth cues. This paper examines perceived depth distortion when viewing stereoscopic VEs from follower perspectives and the impact of these distortions on collaborative spatial judgments. Pairs of participants made collaborative depth judgments of virtual shapes viewed from the CoP or after displacement forward or backward. Forward and backward displacement caused perceived depth compression and expansion, respectively, with greater compression than expansion. Furthermore, distortion was less than predicted by a ray-intersection model of stereo geometry. Collaboration times were significantly longer when participants stood at different locations compared to the same location, and increased with greater perceived depth discrepancy between the two viewing locations. These findings advance our understanding of spatial distortions in multi-user VEs, and suggest a strategy for reducing distortion. 相似文献
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Several surface and volume rendering techniques are compared using nuclear medicine data including several new methods developed by the authors specifically for scintigraphic data. The techniques examined are summed projection, thresholded projection, threshold-based surface illumination, volumetric compositing, maximum-activity projection, sun-weighted maximum-activity projection, and variable attenuation. The advantages and disadvantages of each method are discussed in relation to the goals of three-dimensional display, which are defined herein. Selected images are shown to illustrate the usefulness of the methods. 相似文献