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四川盆地裂缝—孔隙型（或裂缝型）砂岩气藏普遍具有低渗透和裂缝性的特点。各种钻完井液对砂岩储层的损害严重，四川石油管理局井下作业处研究开发了SD土酸解堵酸化体系，该酸液体系以解除泥浆污染堵塞为主要目的，具有优良的配伍稳定性，特别对粘土及漏入储层堵塞孔道的泥浆等堵塞物具有较好的溶解能力，能达到解堵、恢复储层产能的效果。该土酸体系还可作为加砂压裂的预处理液，具有降低地层破裂压力、改善储层可压裂性的功效，具有很好的推广应用价值。文章主要介绍了SD土酸解堵酸化体系的作用原理、性能、现场配制及安全防护与施工应用，并介绍了解堵酸化井的评层选井要点，为了能使土酸解堵酸化获得更理想的增产效果，就必须综合分析静、动态地质资料，充分认识储层的潜在增产能力，来决定是否进行土酸解堵酸化。同时也简单介绍了措施井的后期管理。     

SCO Unix OPEN Server V5.04系统故障特征、分析及解决

该文主要介绍了SCO Unix系统在应用过程中的常故障及解决的办法。     

Fracture gradient prediction: an overview and an improved method

Abstract The fracture gradient is a critical parameter for drilling mud weight design in the energy industry. A new method in fracture gradient prediction is proposed based on analyzing worldwide leak-off test (LOT) data in offshore drilling. Current fracture gradient prediction methods are also reviewed and compared to the proposed method. We analyze more than 200 LOT data in several offshore petroleum basins and find that the fracture gradient depends not only on the overburden stress and pore pressure, but also on the depth. The data indicate that the effective stress coefficient is higher at a shallower depth than that at a deeper depth in the shale formations. Based on this finding, a depth-dependent effective stress coefficient is proposed and applied for fracture gradient prediction. In some petroleum basins, many wells need to be drilled through long sections of salt formations to reach hydrocarbon reservoirs. The fracture gradient in salt formations is very different from that in other sedimentary rocks. Leak-off test data in the salt formations are investigated, and a fracture gradient prediction method is proposed. Case applications are examined to compare different fracture gradient methods and validate the proposed methods. The reasons why the LOT value is higher than its overburden gradient are also explained.     

基于WBS的关键链项目管理贝叶斯网络模型分析方法

在工作分解结构(WBS)和贝叶斯网络技术的基础上,结合WBS单元之间的时序关系和资源约束条件,建立了基于WBS的关键链项目管理贝叶斯网络模型(CCPMBN).首先给出了基于项目任务的WBS模型,然后描述了WBS单元加入时序关系和资源约束后与贝叶斯网络的关系,并分析了CCPM的工序节点的化简方法、节点之间有向边的方向和节点的概率分布计算,接着概述了CCPMBN的建模步骤.最后,以某城市的轨道交通工程项目工作分解结构为例,说明CCPMBN的建模过程,为应用高效贝叶斯网络算法和工具软件进行项目进度管理提供了新的领域.     

电子元器件的可靠性分析

分析了电子元器件的可靠性,包括可靠性的定义,可靠性指标,电子元器件在不同环境条件下的不同特征,元件失效的规律,发生故障的概率等.     

用于智能功率集成电路的PTG-LDMOST

提出一种用于智能功率集成电路的基于绝缘体上硅(SOI)的部分槽栅横向双扩散MOS晶体管(PTG-LDMOST)。PTG-LDMOST由传统的平面沟道变为垂直沟道,提高了器件击穿电压与导通电阻之间的折衷。垂直沟道将开态电流由器件的表面引向体内降低了导通电阻,而且关态的时候耗尽的JFET区参与耐压,提高单位漂移区长度击穿电压。仿真结果表明:对于相同的10微米漂移区长度,新结构的击穿电压从常规结构的111V增大到192V,增长率为73%。     

On a fast, robust estimator of the mode: Comparisons to other robust estimators with applications

Advances in computing power enable more widespread use of the mode, which is a natural measure of central tendency since it is not influenced by the tails in the distribution. The properties of the half-sample mode, which is a simple and fast estimator of the mode of a continuous distribution, are studied. The half-sample mode is less sensitive to outliers than most other estimators of location, including many other low-bias estimators of the mode. Its breakdown point is one half, equal to that of the median. However, because of its finite rejection point, the half-sample mode is much less sensitive to outliers that are all either greater or less than the other values of the sample. This is confirmed by applying the mode estimator and the median to samples drawn from normal, lognormal, and Pareto distributions contaminated by outliers. It is also shown that the half-sample mode, in combination with a robust scale estimator, is a highly robust starting point for iterative robust location estimators such as Huber's M-estimator. The half-sample mode can easily be generalized to modal intervals containing more or less than half of the sample. An application of such an estimator to the finding of collision points in high-energy proton–proton interactions is presented.     

LT-GaAs with high breakdown strength at low temperature for power MISFET applications

Low temperature grown GaAs has been fabricated containing a limited amount of excess arsenic. The material has a low conductivity in the order of 100KΩ cm, due to hopping in a deep donor band. This σ-LT-GaAs was grown reproducibly by using the lattice mismatch as the primary parameter for substrate temperature calibration. Breakdown fields, in the order of 100kV/cm, are observed for planar structures and increased at low measurement emperatures. Low hopping conductivity and high breakdown field are also observed in the lossy dielectric metal-insulator-semiconductor field-effect transistor device using σ-LT-GaAs as a surface layer. The record radio frequency power density of 4.0W/mm at 77K is extracted from the dc output characteristics.     

假设验证推理方法在乳胶机械故障诊断中的应用

开发了基于专家知识的假设验证推理策略,并应用于乳胶机械故障诊断专家系统.这种诊断系统采用正-反向混合推理的策略.反向推理则首先假设结论再搜索证据,正向推理从证据出发推出结论,然后找到两种推理的交点.     

Robust estimation in very small samples

In experimental science measurements are typically repeated only a few times, yielding a sample size n of the order of 3 to 8. One then wants to summarize the measurements by a central value and measure their variability, i.e. estimate location and scale. These estimates should preferably be robust against outliers, as reflected by their small-sample breakdown value. The estimator's stylized empirical influence function should be smooth, monotone increasing for location, and decreasing–increasing for scale. It turns out that location can be estimated robustly for n3, whereas for scale n4 is needed. Several well-known robust estimators are studied for small n, yielding some surprising results. For instance, the Hodges–Lehmann estimator equals the average when n=4. Also location M-estimators with auxiliary scale are studied, addressing issues like the difference between one-step and fully iterated M-estimators. Simultaneous M-estimators of location and scale (‘Huber's Proposal 2’) are considered as well, and it turns out that their lack of robustness is already noticeable for such small samples. Recommendations are given as to which estimators to use.