大透距电磁波CT法在电站坝基勘查中的应用

跨孔电磁波CT法在勘查岩溶方面大有可为。在西南某电站坝基勘查中,成功地应用了跨孔电磁波CT法,分别在左坝肩和右坝肩中所探查的二对孔间,圈出了岩溶的发育范围。所提交的资料已得到钻探、平硐勘探资料、声波和数字摄像的据互相印证。为进一步施工提供了较好的指导作用。本次勘查使用的是最新型的JW—5Q型大功率仪器和新版的处理软件,并成功地使用高频穿透98m地层,是一次很成功的应用。     

Validation of 3-D curved objects: CAD model and fabricatedworkpiece

This paper proposes a new method to describe and identify a 3-D curved object for the purpose of validating a fabricated object to the design specification. Curved 3-D objects are, in general, difficult to represent and identify because they lack distinct properties such as edges, planes, or cylindrical surfaces which are the building blocks in representing objects. In this paper, the authors propose to use principal axes of a 3-D object to establish a reference for the representation. A method of obtaining an inertia matrix from a 3-D range image is developed. The unique set of principal axes is obtained from the inertia matrix of an object with an arbitrary 3-D position and orientation, and the object can be described uniquely on these principal axes. On the principal axes, an object is described by a set of features describing the shape of the object such as spine, section size, section orientation, and section contraction. The features are used for comparing two objects for the validation purpose. The authors also propose a direct measure of similarity between two objects as a mean-squared difference of radii. As an experiment, two 3-D object models are designed through a CAD package, and fabricated objects are compared with the designed models for validation purposes     

攀钢“501”滑动水口液压驱动系统的研制

介绍了为攀钢“５０１”滑动水口研制的专用液压驱动系统，对该系统的工作原理，性能特点，主要元件（设备）的选择原则等作了较为详细的说明介绍。     

地域通信网的干扰技术研究

本文在分析地域通信网结构及组成的基础上,研究了对地域通信网实施的节点破坏、末端信息封锁、局部阻塞瘫痪等对抗方法,并使用干扰地域通信网的程度、节点干扰率、末端节点封锁率和传递信息误差率等指标对干扰效果进行评估。     

High voltage (>1kV) and high current gain (32) 4H-SiC power BJTs using Al-free ohmic contact to the base

This letter reports the design and fabrication of 4H-SiC bipolar junction transistors with both high voltage (>1kV) and high dc current gain (/spl beta/=32) at a collector current level of I/sub c/=3.83A (J/sub c/=319 A/cm/sup 2/). An Al-free base ohmic contact has been used which, when compared with BJTs fabricated with Al-based base contact, shows clearly improved blocking voltage. A specific on-resistance of 17 m/spl Omega//spl middot/cm/sup 2/ has been achieved for collector current densities up to 289 A/cm/sup 2/.     

用屏蔽暂堵技术封堵水平井裂缝性漏层

克拉玛依油田HW702水平井的大斜度段和水平段,将穿越纵向裂缝发育的二叠系佳木河组储层。为安全钻进和保护油层,用超细碳酸钙和磺化沥青复配后加入复合离子钻井液中成屏蔽暂堵的堵漏钻井液。室内用岩心试验,屏蔽暂堵后渗透率可降为0,暂堵深度小于3cm,可用酸化和射孔解堵。现场使用效果也很好,使HW702水平井顺利完钻,并获得工业油气流。     

注蒸汽开发稠油油藏采收率计算公式探讨

从辽河油区的地质条件和开发特征出发．立足单因素分析，在着重研究渗进率、净总厚度比和单层厚度对原油采收率影响的基础上。利用《价值工程》中的“功能重要评价法”，优化出不同类型稠油油藏蒸汽吞吐和蒸汽驱开发阶段的采收率计算公式．经实际资料验证，该公式对油田开发前期确定采收率丰和可采储量，具有较好的适用性。