水平井眼轨迹对气井出砂趋势及工作制度的影响

出砂是影响油气井正常生产的重要因素之一。借助FEPG有限元程序自动生成平台，建立了三维应力场弹塑性地层出砂模型，并运用有限元法计算分析了不同轨迹的裸眼井井壁周围的有效塑性应变分布规律及出砂趋势，研究了气藏压力衰竭对完井方式的影响。研究表明，水平井眼轨迹对出砂有重要的影响，同一地应力环境下向不同方位延伸的水平井在投产时应该采取不同的生产压差和不同的生产制度，水平井眼轨迹对出砂的影响程度随着3个地应力差异的增大而加剧。气藏压力衰竭对井壁的稳定性和出砂趋势都有重要影响。随着气藏压力的衰竭，井壁稳定性将变得越来越差，最终导致井筒出砂。因此，对气井完井不仅应该考虑到气藏开发初期地层的稳定性状况，而且还应该考虑到气藏压力衰竭后可能出现的井壁失稳问题。     

Synthesis of diamond crystals and films using an oxygen-acetylene flame under atmosheric pressure

Diamond growth with rates up to 100 to 140 μm/hr was achieved using an oxygen-acetylene combustion spraying technique in an atmospheric environment. Investigations on the processing indicated that the gas flow ratio, substrate position, substrate temperature, temperature distribution, and substrate pretreatment were the most important factors affecting the growth of diamond crystals. Evaluation by means of X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and electron probe microanalysis showed that the synthesized diamond was nearly perfect in morphology, structure, and purity.     

α-Fe_2O_3(SO_4~(2-),Sn)气敏电阻的温度响应特性

在气敏温度区域内研究了α-Fe_2O_3(SO_4~(2-),Sn)材料的电阻-温度特性,认为表面结构的变化导致温度特性出现峰值并呈现气敏性。可利用空气中电阻温度特性提供的信息改性或发现新的气敏材料。     

基于PRO/E三维管道轨迹专用检具的设计

介绍使用该软件组件设计模块中的高级工具———切除 (CutOut)功能设计高精度三维轨迹管道零件检具的方法 ,该方法具有高效和精密等特点。     

Analysis and optimization of weakly coupled thermoelastoplastic systems with applications to weldment design

A systematic approach for the design of weakly coupled thermoelastoplastic systems is presented. The Newton–Raphson iteration method is used in the solution process so that analytic design sensitivity formulations may be efficiently derived via the direct differentiation technique. The derived formulations are suitable for finite element implementations. Analysis and sensitivity analysis capabilities are combined with numerical optimization to form an optimum design algorithm. To demonstrate the algorithm, we optimally design a weldment with respect to manufacturing and service life aspects.     

多变量系统敏感性及鲁棒性综合最优的H∞解耦设计方法

本文利用H∞设计理论提出了一种多变量系统敏感性及鲁棒性综合最优的解耦设计方 法,证明了单变量系统所能达到的最优敏感性及鲁棒性指标值仅由被控对象右半平面的零极 点决定,而与左半平面的零极点无关.另外,本文对谱分解及模型匹配问题的求解算法作了改 进,给出了一个算例.     

复合材料压缩破坏模式的缺陷敏感性

本文基于弹塑性分叉理论研究单向纤维增强复合材料的压缩破坏模式和压缩强度对缺陷的敏感性问题。对于常见复合材料,所得结论是:无缺陷或者小缺陷情况的破坏模式为倾斜破坏带;大缺陷情况的破坏模式为水平破坏带;形成水平破坏带的压力值小于形成倾斜破坏带的压力。     

Temperature–stress–strain trajectory modelling during thermo-mechanical fatigue

The isothermal strain‐life approach is the most commonly used approach for determining fatigue damage, particularly when yielding occurs. Computationally it is extremely fast and generally requires elastic finite element analyses only. Therefore, it has been adapted for variable temperatures. Local temperature—stress–strain behaviour is modelled with an operator of the Prandtl type. The hysteresis loops are supposed to be stabilized and no creep is considered. The consequences of reversal point filtering are analysed. The approach is finally compared to several thermo‐mechanical fatigue tests and the Skelton model.     

Age effects in coding tasks: Componential analysis and test of the sensory deficit hypothesis.

Multiple forms of a symbol-digit substitution task were used to provide a componential analysis of age differences in coding task performance. The results demonstrated age differences in feature encoding, memory, and visual search. A 2nd experiment was conducted with young adults to investigate a sensory deficit as a locus of age differences. The spatial contrast sensitivity deficit of older adults was simulated on forms by applying a digital filter. Persons in the age-simulated contrast condition performed worse than those in the normal contrast condition. The stimulus degradation effect was linked to visual search speed. The study illustrates the utility of componential analysis and offers direct support for the hypothesis that sensory deficits affect performance on tasks used to assess intelligence (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Measurement of forming trajectories during drilling

Results are provided for an experimental study of forming trajectories during drilling and the effect on them of cutting speed and drilling depth. __________ Translated from Izmeritel’naya Tekhnika, No. 8, pp. 31–33, August, 2006.