山西晋城煤矿区初始地应力场反演分析

针对山西晋城成庄煤矿区的地形地貌特征,考虑地应力形成的基本原理,结合矿区地应力实测资料,建立三维计算模型,通过多元线性回归分析方法求得各基本应力场的回归系数,最后进行线性叠加,较为准确的反演出了煤矿区的初始地应力场。反演的结果表明,该区域的应力场特征表现为不仅仅是以自重应力为主导,同时还受到水平的构造应力场的综合作用。     

Load Forecasting Technique for System Expansion in Isolated Area Using Time Invariant Socio-Economic Factors of Identical Agglomerations

Load forecasting is a critical issue for operational planning as well as grid expansion to ensure an uninterruptable electric power system. Being a small but densely populated country in South Asia, Bangladesh has many isolated places which are not connected to national grid yet. If concern authority opts to expand grid to those areas, they need reliable demand data for designing and dimensioning of different power system entities, e.g., capacity, overhead line capacity, tie line capacity, spinning reserve, load-shedding scheduling, etc., for reliable operation and to prevent possible obligatory redesigning. This paper represents an analysis to forecast the electricity demand of an isolated island in Bangladesh where past history of electrical load demand is not available. The analysis is based on the identification of factors, e.g., population, literacy rate, per capita income, occupation, communication, etc., on which electrical load growth of an area depends. Data has been collected from the targeted isolated area and form a grid connected area which is similar to target area from social and geographical perspective. Weights of those factors on load have been calculated by matrix inversion. Demand of the new area is forecasted using these weights factors by matrix multiplication.     

Influence of novel surface modifying macromolecules and coagulation media on the gas permeation properties of different polymeric gas separation membranes

Integrally skinned asymmetric membranes for the separation of O₂ and N₂ were fabricated by the phase inversion technique from polysulfone, polyetherimide, and polyimide. Two types of surface modifying macromolecules (SMMs) including hydrophilic SMM (LSMM) and charged SMM (cSMM) were synthesized and blended with the casting solution to modify the membrane surface. The cast film was then immersed in the first coagulant alcohol (methanol, ethanol, or isopropanol) for a predetermined period, before being immersed in the second coagulant (water). The SMMs used in these experiments were laboratory synthesized by the two‐step process of polyurethane prepolymer synthesis and end capping, before being characterized by differential scanning calorimetry. Their molecular structure was determined from the molecular weight obtained by gel permeation chromatography. The membranes were characterized by contact angle measurement and O₂ and N₂ gas permeation performance. Attempts were made to interpret the gas permeation data by delayed demixing affected by solubility parameters of polymer, solvent, and nonsolvent. Furthermore, the permeation performance of cSMM membranes was interpreted by the solvation of the charged sulfonate groups present in cSMM. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

High-gain microwatt composite cascode op amps

This article discusses the composite cascode stage, both single-ended and differential, operating in the weak inversion or moderate inversion region. The gain of the MOS composite cascode differential stage can exceed 100,000?V/V, a figure that has never been reported in the literature. For low-frequency applications, this configuration can be used to fabricate op amps that have high-gain, low-power and low-nonlinear distortion. Two different architectures, both having two gain stages are reported. The first op amp uses the Widlar architecture to achieve a gain of 117?dB, a power dissipation of 110?µW and uses a compensation capacitor of only 3.5?pF. The second op amp uses a class AB stage for the second and final stage and utilises the parasitic capacitance at the output of the first stage for compensation. This self-compensating op amp has a gain of 110?dB and a power dissipation of 21?µW.     

频率波数域叠前深度偏移及其在微机上的实现

叠前深度偏移技术的推广应用一直由于叠前数据量巨大和计算量异常密集而受到限制。为突破这一制约, 对基于频率波数域的快速叠前深度偏移方法进行了算法优化, 在微机上完成了原来只有在大型计算机上才能实现的工作, 并分别对复杂地质模型和实际二维地震数据成功实现了叠前深度偏移, 取得满意的结果。     

连续本体法ABS制备工艺进展

综述了连续本体法丙烯腈/丁二烯/苯乙烯(ABS)的制备工艺、接枝和相反转过程的工艺特征、调控粒径及改进性能的方法,指出各种制备工艺的共性和区别,总结出连续本体法ABS制备工艺的关键.     

Meshless Local Petrov-Galerkin Method for Plane Piezoelectricity

Piezoelectric materials have wide range engineering applications in smart structures and devices. They have usually anisotropic properties. Except this complication electric and mechanical fields are coupled each other and the governing equations are much more complex than that in the classical elasticity. Thus, efficient computational methods to solve the boundary or the initial-boundary value problems for piezoelectric solids are required. In this paper, the Meshless local Petrov-Galerkin (MLPG) method with a Heaviside step function as the test functions is applied to solve two-dimensional (2-D) piezoelectric problems. The mechanical fields are described by the equations of motion with an inertial term. To eliminate the time-dependence in the governing partial differential equations the Laplace-transform technique is applied to the governing equations, which are satisfied in the Laplace-transformed domain in a weak-form on small subdomains. Nodal points are spread on the analyzed domain and each node is surrounded by a small circle for simplicity. The spatial variation of the displacements and the electric potential are approximated by the Moving Least-Squares (MLS) scheme. After performing the spatial integrations, one obtains a system of linear algebraic equations for unknown nodal values. The boundary conditions on the global boundary are satisfied by the collocation of the MLS-approximation expressions for the displacements and the electric potential at the boundary nodal points. The Stehfest's inversion method is applied to obtain the final time-dependent solutions.     

测井地震结合储层参数推广反演技术及应用

通过储层测井精细分析评价 ,得到各井准确的储层参数 ,然后 ,利用测井地震资料联合波阻抗宽带约束反演、剖面地震属性提取、多维地震属性约束储层物性反演等技术 ,将地震剖面转换为储层参数剖面 ,最终得到储层厚度、孔隙度、饱和度、H(即有效厚度与孔隙度的乘积 )、HSg(即有效厚度、孔隙度、含气饱和度三者的乘积 )等各种储层参数的平面分布图 ,进而进行储层评价、油藏描述。     

A comparison of heuristics for family and job scheduling in a flow-line manufacturing cell

This paper proposes new procedures for scheduling a flow-line manufacturing cell and compares the results obtained by using these new procedures to results obtained using procedures developed by Wemmerlov and Vakharia, Skorin-Kapov and Vakharia, and Sridhar and Rajendran. The procedures are evaluated on the basis of the makespans generated by solutions for test problems. The results show that the new procedures can efficiently generate good makespans and that results obtained by using the tabu search procedure developed by Skorin-Kapov and Vakharia can be improved if a starting set of job and family sequences is generated by one of the new procedures.     

A note on the computation of high-dimensional integral images

The integral image approach allows optimal computation of Haar-based features for real-time recognition of objects in image sequences. This paper describes a generalization of the approach to high-dimensional images and offers a formula for optimal computation of sums on high-dimensional rectangles.