Drying Kinetics of a Porous Spherical Particle and the Inversion Temperature

A model is presented for drying of a single porous particle with superheated steam and humid air. Experimental data for spherical porous ceramic particle reported in the literature were used for the validation of the model. An inversion temperature at which the evaporation rates within superheated steam and humid air are equal was predicted. The effect of thermophysical properties of the particle (permeability 10^-14 - 10^-17 m², diameter 3 × 10^-3 - 10 × 10^-3 m) and operating variables (gas mass flux 0.26 - 0.78 kg m^-2 s^-1, drying agent temperature 120-200°C) is tested. The inversion temperature is shown to be affected by the thermophysical properties of the porous particle and of the drying agent.     

最大熵在感应测井反演中的应用

常规的反演方法是对感应测井资料进行线性反褶积。由于感应测并获得的响应曲线是地层非线性时变滤波的结果,感应测井响应随地层电导率发生非线性变化。本文把熵的概念引入到感应测井反演中。用最大熵方法分别设计出实部信号和虚部信号所对应的反滤波因子,两条反映测井响应随电导率非线性变化的非线性函数也被拟合出来。文章最后用设计出的滤波因子及被拟合出的非线性函数对模拟相量感应测井资料进行了相量反褶积。处理结果表明,围岩效应和趋肤效应基本被消除。本方法与常规的三点反褶积法相比,克服了过聚焦现象,提高了精度。     

CFRP压力容器固化成型过程中边界条件的确定

文中应用总放热系数等效考虑了CFRP压力容器固化过程中热压釜辐射与对流边界条件。将有限元法引入瞬态热传导的反问题，根据试验测量的温度曲线，并结合最优化理论确定合理的热压釜热边界条件。结果表明：平板试验得到了总放热系数序列，其计算温度与测试温度的最大温差为0．147℃。由此，可以将得到的总放热系数序列作为CFRP压力容器固化成型过程的等效热边界条件，为其固化成型的数值模拟提供计算基础。     

Characteristics of selective adsorption using D-phenylalanine imprinted terpolymer beads

A D-Phenylalanine (Phe) imprinted terpolymer, Polyacrylonitrile-Poly(acrylic acid)-Poly(acryl amide) (Poly(AN-AA-AAm)) bead was prepared by the wet-phase inversion method. Acrylamide (AAm) and acrylic acid (AA) were used as the functional monomer and acrylonitrile (AN) was used as a physical cross linker. The characteristics of selective adsorption by the D-Phe imprinted terpolymer beads were investigated at high concentrations of Phe racemate solution, 1 g Phe/L, and 10 g Phe/L. The adsorption selectivity of the D-Phe imprinted terpolymer beads prepared by anin-situ implanting method reached 0.82 and 0.8 at 1.0 g and 10 g Phe/L racemate solution, respectively, and almost all of the adsorbed D-Phe and about 43% of the adsorbed L-Phe were desorbed by 4% acetic acid. The uptake capacities of the terpolymer beads were maintained for several repeated batches.     

多重网格法在地球物理正反演应用研究中的进展

现阶段地球物理三维勘探面临越来越复杂的问题,其要求更精细的三维网格剖分,现有的一些方法随着网格节点的增加其收敛速度相应减慢。对于应用中更复杂实际模型、更细密网格剖分以及更快收敛速度要求,难于有进一步提高。要有所突破,需借助计算数学最新进展,引入新的高效算法。多重网格法是近二十年迅速发展的一种求解微分方程近乎最优的新算法。本文首先简单介绍了多重网格法基本原理和运算格式,着重介绍了当前国内外多重网格法在地球物理正反演中的应用成果和发展现状。此外,对多重网格法在地球物理正反演中的应用前景及发展趋势进行了展望。     

潜江凹陷建新地区地震储层预测研究

以古地貌分析、砂体展布特征为指导,开展了潜江凹陷建新地区多种技术手段的地震储层预测研究。结果表明,振幅类与波形类属性是该区的敏感性参数,并且通过本地区的岩石物理分析,认为波阻抗也能较好地区分储层;在刻画储层展布形态的同时与构造相叠合落实了多个构造-岩性圈闭,进一步明确该区构造-岩性油藏的勘探潜力。     

Limiting negations in non-deterministic circuits

The minimum number of NOT gates in a Boolean circuit computing a Boolean function f is called the inversion complexity of f. In 1958, Markov determined the inversion complexity of every Boolean function and, in particular, proved that log₂(n+1) NOT gates are sufficient to compute any Boolean function on n variables. In this paper, we consider circuits computing non-deterministically and determine the inversion complexity of every Boolean function. In particular, we prove that one NOT gate is sufficient to compute any Boolean function in non-deterministic circuits if we can use an arbitrary number of guess inputs.     

基于SAR数据的干旱区冲积扇地表粗糙度反演

干旱区冲积扇的表面特征是研究古气候、古环境变化的重要途径,冲积扇扇面粗糙度是反映冲积扇演化的重要指示。合成孔径雷达(SAR)已成为冲积扇扇面特征参数提取的有力工具。然而,现有的地表粗糙度反演模型在干旱区难以得到较好的反演结果。利用Radarsat-2极化数据,开展了疏勒河冲积扇地表粗糙度反演研究,在OH模型的基础上,提出了更加适合干旱区地表粗糙度反演的新方法。经过实测数据的验证,新方法能够解决原有模型在干旱区粗糙度反演结果偏大的问题,并取得了较好的反演结果。该模型的提出为干旱区冲积扇表面参数提取提供了可靠的工具。     

Nonlinear minimum-time control with pre- and post-actuation

This article studies the time-optimal output transition problem to change the system output, from an initial value (for all time ) to a final value (for all time ), for invertible nonlinear systems. The main contribution of the article is to show that the use of pre- and post-actuation input outside the transition interval I_T=[0,T] can reduce the transition time T beyond the standard bang–bang-type inputs for optimal state transition. The advantage of using pre- and post-actuation is demonstrated with an illustrative nonlinear example.     

Restricted compositions and permutations: From old to new Gray codes

Any Gray code for a set of combinatorial objects defines a total order relation on this set: x is less than y if and only if y occurs after x in the Gray code list. Let ? denote the order relation induced by the classical Gray code for the product set (the natural extension of the Binary Reflected Gray Code to k-ary tuples). The restriction of ? to the set of compositions and bounded compositions gives known Gray codes for those sets. Here we show that ? restricted to the set of bounded compositions of an interval yields still a Gray code. An n-composition of an interval is an n-tuple of integers whose sum lies between two integers; and the set of bounded n-compositions of an interval simultaneously generalizes product set and compositions of an integer, and so ? put under a single roof all these Gray codes.As a byproduct we obtain Gray codes for permutations with a number of inversions lying between two integers, and with even/odd number of inversions or cycles. Such particular classes of permutations are used to solve some computational difficult problems.