NMR measurement of bitumen at different temperatures

Heavy oil (bitumen) is characterized by its high viscosity and density, which is a major obstacle to both well logging and recovery. Due to the lost information of T2 relaxation time shorter than echo spacing (TE) and interference of water signal, estimation of heavy oil properties from NMR T2 measurements is usually problematic. In this work, a new method has been developed to overcome the echo spacing restriction of NMR spectrometer during the application to heavy oil (bitumen). A FID measurement supplemented the start of CPMG. Constrained by its initial magnetization (M0) estimated from the FID and assuming log normal distribution for bitumen, the corrected T2 relaxation time of bitumen sample can be obtained from the interpretation of CPMG data. This new method successfully overcomes the TE restriction of the NMR spectrometer and is nearly independent on the TE applied in the measurement. This method was applied to the measurement at elevated temperatures (8-90 degrees C). Due to the significant signal-loss within the dead time of FID, the directly extrapolated M0 of bitumen at relatively lower temperatures (<60 degrees C) was found to be underestimated. However, resulting from the remarkably lowered viscosity, the extrapolated M0 of bitumen at over 60 degrees C can be reasonably assumed to be the real value. In this manner, based on the extrapolation at higher temperatures (> or = 60 degrees C), the M0 value of bitumen at lower temperatures (<60 degrees C) can be corrected by Curie's Law. Consequently, some important petrophysical properties of bitumen, such as hydrogen index (HI), fluid content and viscosity were evaluated by using corrected T2.     

GaAs／AlGaAs多量子阱器件均匀性研究

从几个方面研究了ＧａＡｓ／ＡｌＧａＡｓ多量子阱红外探测器的均匀性,找到了影响其均匀性的几个因素,今后的工作奠定了基础。     

Quantales的代数余核和子Quantales

在研究代数余核的一些性质的基础上,得到了Quantales的映射构成代数余核的条件;同时证明了由wellinside关系生成的某种集是子Quantale．     

Highly selective molecular recognition and high throughput detection of melamine based on molecularly imprinted sol-gel film

Multimode reader has been generally applied in immunoassay, and in the proposed paper, the 96 well micro-plate was modified with molecularly imprinted melamine sol-gel film, based on which the highly selective and high throughput detection of melamine was achieved. Melamine was imprinted into silica sol-gel films directly using phenyltrimethoxysilane and methyltrimethoxysilane as functionalized organosilicon precursors. The binding characteristic of the imprinted film to melamine was evaluated by equilibrium binding experiments and the morphology was studied by scanning electronic microscope (SEM). Scatchard analysis was carried out to estimate the binding parameters of the imprinted film. The proposed method exhibited excellent selectivity because of specific recognition of MM by molecularly imprinted film. Under the optimum conditions, the chemiluminescence (CL) intensity had a linear relationship against the concentration of melamine over the range of 0.1-50 μg mL⁻¹ with a lower detection limit of 0.02 μg mL⁻¹.     

Theoretical and experimental evaluation of screen-printed tubular carbon ink disposable sensor well electrodes by dc and Fourier transformed ac voltammetry

Mass-produced, screen-printed, carbon-ink-based microtubular band (well) electrodes, suitable for routine sensing applications, have been fabricated and evaluated with respect to their theoretical and analytical performance. Microscopic examination of the electrode surface reveals they are inherently rough and could easily suffer from high and variable resistance, capacitance and area, unless care is taken to minimise these problems. Simulation models have been applied to analyse cyclic voltammetric responses obtained at the well electrodes. Results of these theoretical calculations further demonstrate the care needed with electrode design and resistance in carbon ink electrodes. Substantial differences in voltammetry when wells are produced by mechanically punching or laser drilling are considered. The application of multi- and single-frequency Fourier Transform ac voltammetry, previously applied to planar carbon ink disc electrodes for quality control purposes, is now demonstrated with respect to the microtubular band electrode geometry. Theoretical and practical limitations are discussed, as is the analytical application to the reversible redox couple in the presence of oxygen in aqueous solution. Dedicated to Keith on his 80th birthday, a good friend and colleague.     

GDI+测井曲线绘图中效率提升的研究

GDI+提供了快速、简单、有效的程序开发方式.大量测井原始数据生成测井曲线时,绘制对象的增加严重制约了GDI+的绘图效率.双缓冲技术的使用,可以有效避免图形的闪烁;使用内存中已有图形,可以减少测井曲线的绘制过程,显著提高图形绘制效率.     

Dynamic behavior of water wells coupled to PV pumping systems

Evaluation of a water supply system requires an overall analysis of its behavior, including the well performance and drawdown characteristics. The response of the water well is usually characterized by a single relationship between water level and water flow, representing its quasi‐equilibrium behavior. However, for days with large and rapid variations of irradiance this relationship does not correspond to the well‐equilibrium curve. In order to simulate the well behavior it has been developed a model that takes into account the variation of water level, pressure at the entrance of the well and static pressure of the aquifer, all of them related to the water flow. The model also considers the energy conservation equation of the system through the relationship among hydraulic load, water flow, and collected irradiance. Results of simulations show that, for days with large variations in solar irradiance, the static and dynamic analysis exhibit large differences in the instantaneous water head. The dynamic analysis shows that the water well tends to attenuate the fluctuations of the water head through a negative feedback mechanism. The model helps to understand some facts observed in the field. For example, the dispersion of points in the flow rate versus solar irradiance curves. The maximum drawdown obtained with the dynamic model is considerably smaller than the one predicted with the quasi‐equilibrium analysis. That difference can represent some savings in terms of water well hardware (drilling, wiring, and piping) for programs involving the installation of a large number of systems. The slowdown of water column variations, shown by the dynamic model, signifies that the motor‐pump system is not so intensively demanded as the quasi‐equilibrium analysis would suggest, resulting in longer lifetime prospects. Copyright © 2007 John Wiley & Sons, Ltd.     

BCH-代数的闭模糊理想

引入了BCH-代数的闭模糊理想、子代数及优BCH-代数的概念,讨论它们的性质,获得若干结果。     

复合量子阱Ge_(0.3)Si_(0.7)/(Ge_(0.3)Si_(0.7))_m-(Si)_m/Ge_(0.3)Si_(0.7)的电子能带结构

采用建立在经验赝历势基础上的推广k·P方法计算了复合量子阱Ge0.3Si0.7／（Ge0.3Si0.7）m-（Si）m／Ge0.3Si0.7的电子束缚能组及其活界面方向的色激关系,并与通常的单带模型下的包络函数方法的计算结果进行了比较。结果表明由于超晶格中子能带的形成,邻近能带间的互作用使通常单带模型下的包络函数方法不再能适用于复合量子阱的计算。计算结果也表明复合量子阱的电子束缚能级沿界面方向在kx＜0.1（2π/a）范围内基本上不随kx变化。     

Well‐posedness of fractional degenerate differential equations with finite delay on vector‐valued functional spaces

We study the well‐posedness of the fractional degenerate differential equations with finite delay on Lebesgue–Bochner spaces , periodic Besov spaces and periodic Triebel–Lizorkin spaces , where A and M are closed linear operators on a Banach space X satisfying , F is a bounded linear operator from (resp. and ) into X, where is given by when and . Using known operator‐valued Fourier multiplier theorems, we give necessary or sufficient conditions for the well‐posedness of in the above three function spaces.