载水油气井生产测井方法研究

油井或气井出现载水现象后,不断上升的水柱不仅会降低储层与井筒间的压差影响油气产出,而且改变了井筒中流体介质分布和速度分布,造成生产动态监测方面的困难。提出了依据流量计、密度计、持水率计等曲线判断油井或气井是否载水的新方法,基于对不同井段的流型进行了分析,提出了相应产出剖面测井仪器系列及其测井资料处理解释模型。     

浅谈变频器与长电缆相连时电动机的失效现象

在实际应用中 ,当电动机与PWM电压供电的变频器间电缆很长时 ,电动机侧会出现高压现象 ,而过高的终端电压会使电动机的绝缘失效。在对电动机失效现象的机理进行分析的同时 ,给出了几种防止电动机进一步失效的方法     

镧系元素性质递变的双峰现象

本文从镧系的电子结构和化学键参数分析了镧系元素性质遂变的双峰现象的本质。并探讨了它在稀土分离提取工艺方面应用的可能性。     

DC conduction associated with electric field-induced motion in mineral oils

The contributions of the electrohydrodynamic (EHD) motion to the dc electric conduction in insulating oils are presented. The effects of solid/liquid interfaces on the EHD motion have been studied with a mineral oil-polypropylene mixed dielectric and a mineral oil single dielectric. The time dependence of current, schlieren images of EHD motion induced in the oil layer and response signals of density change in the vicinity of the electrode/oil interfaces after application of step voltage are observed. The results are as follows: (1) the EHD motion occurs at the positive electrode/oil interfaces when a voltage above critical voltage is applied; (2) a time delay exists between the application of step voltage and the onset of EHD motion. The time is inversely proportional to the applied voltage; (3) the EHD motion increases current and produces a peak phenomena in the current waveform; and (4) the time difference between peak current time and the delay time is inversely proportional to applied voltage.     

不同渗漏强度下淹水土壤中NH_4~＋－N转化运移的数值模拟

文中提出了淹水土壤中以氧化－还原分异现象为基础的ＮＨ＋４－Ｎ转化运移的数学模型，通过不同渗漏强度下淹水土壤表施碳铵后的土柱试验验证了混合有限解析解数值模型，进而模拟了不同水肥管理条件下淹水土壤中ＮＨ＋４－Ｎ迁移及分布。     

Pseudogap Phenomenon in Single Phase Hg-1223 Cuprate Superconductors

The single phase Hg-1223 cuprate superconductors have been successfully fabricated. The postannealing treatment under oxygen (O₂) gas and argon (Ar) gas with different annealing time was performed in order to obtain various hole density samples. These samples were used to study the pseudogap phenomenon in the normal phase. With the plot of ln[1/(T) – 1/_N(T)] against 1/T, three characteristic temperatures T*, T _S, and T _F were obtained, which describe the role of the pseudogap phenomenon. The magnitudes of the pseudogap were extracted from the slope of the stated plots. It is found that the three characteristic temperatures T*, T _S, and T _F change with the hole density linearly. The relationship between T* and T _C goes within T* = T*_op+₀ (1–T_C/T^max _C) , where T*_op and T _C ^max are the pseudogap opening temperature and the critical temperature for the optimal sample. It is also found that the pseudogap phenomenon only exists below the optimal regime in the hole doping phase diagram.     

Reconstruction of Piecewise Smooth Functions from Non-uniform Grid Point Data

Spectral series expansions of piecewise smooth functions are known to yield poor results, with spurious oscillations forming near the jump discontinuities and reduced convergence throughout the interval of approximation. The spectral reprojection method, most notably the Gegenbauer reconstruction method, can restore exponential convergence to piecewise smooth function approximations from their (pseudo-)spectral coefficients. Difficulties may arise due to numerical robustness and ill-conditioning of the reprojection basis polynomials, however. This paper considers non-classical orthogonal polynomials as reprojection bases for a general order (finite or spectral) reconstruction of piecewise smooth functions. Furthermore, when the given data are discrete grid point values, the reprojection polynomials are constructed to be orthogonal in the discrete sense, rather than by the usual continuous inner product. No calculation of optimal quadrature points is therefore needed. This adaptation suggests a method to approximate piecewise smooth functions from discrete non-uniform data, and results in a one-dimensional approximation that is accurate and numerically robust.      

完备正交V-系统及其在几何信息重构中的应用

考虑到几何信息频谱分析的需要,采用L2[0,1]上一类新的完备正交函数系(称之为V-系统),针对CAGD中的几何图组,给出一类信息重构方法.V-系统由分段多项式组成,包括各个层次的间断函数,具有多分辨分析特性和局部性.基于V-系统的算法可以有效地消除几何信息表达中的Gibbs现象.实验结果表明,基于V-系统的几何图组信息重构的方法,为开展几何图组的频谱分析研究打下了基础.     

多层次-跨尺度物理中并行DVM-DAC算法

多尺度现象及相关理论方法是复杂物质系统研究中重要的科学问题.单一的量子力学或分子动力学方法无法解释多尺度体系中存在的现象.第一原理离散变分线性标度（DVM-DAC）算法是一种有效的大尺度体系计算方法.它采用分而治之方案,获得了O（n）的计算复杂性.但由于需要求解大量的特征方程,实现中存在严重的计算瓶颈.发展了一种并行DVM-DAC算法并付诸实现,有效地解决了原有算法的计算瓶颈问题.测试结果表明,并行DVM-DAC算法具有很好的可扩展性,并成功完成104碳纳米管原子体系的计算,为多尺度体系研究提供重要工具.     

基于MNF和SVM的高光谱遥感影像分类研究

通过分析高光谱遥感影像分类的现状及遇到的困难,以OMIS1高光谱数据为实验数据,提出了基于最小噪声分离(Minimum Noise Fraction-MNF)变换和支持向量机(Support Vector Machine-SVM)的高光谱遥感影像分类方法。分类实验结果表明:与传统的最大似然分类法(Maxi mum Likelihood Classification-MLC)比较,该方法克服了Hughes现象,分类速度得以提高,总体分类精度达到94.85%,从而表明了该方法用于高光谱遥感影像分类的实用性和优越性。