手写体字符识别的人工神经网络方法的研究

本文总结了生物视觉神经系统从视网膜到初级树皮层的信息处理特点，并指出其与小波交换概念相似处。在此基础上设计了人工神经网络字符识别器，用于数码识别．仿真结果初步显示该模型具有较好的推广能力和分类能力．采用广义能量函数法进一步改善了模型性能。     

多层前向网络的广义能量约束算法及其在信号处理中的应用

本文提出一种用于多层前向网络的广义能量约束算法。新的能量函数不仅包括误差平方和项,而且还包括某些能使网络获得所期望的性能的约束项.讨论了某些典型的约束形式,施加在权重矢量或隐藏层输出或网络结构上.将本方法用于信号处理中广泛采用的奇异值分解(SVD)问题,取得较好效果.此方法还可以引申到主分量分析(PCA)。方法具有高度灵活性,并使矩阵的并行运算成为可能.能量约束中还可以引入有关信号特征的先验知识,从而使作信源分解时对信号和传输阵的正交要求有所降低.初步仿真结果表明本方法有良好应用前景.     

Enhanced dehumidification performance of PVA membranes by tuning the water state through incorporating organophosphorus acid

A novel thin film composite membrane with superior propylene dehumidification performance was prepared by coating a high hydrophilic organophosphorus acid ethylene diamine tetra(methylene phosphonic acid) (EDTMPA) doped poly(vinyl alcohol) (PVA) on polysulfone (PS) hollow fiber membranes. Experimental studies and molecular dynamics simulations were combined to probe the existing states and the transport mechanism of water in the membranes. Water vapor sorption experiments revealed that the enhanced dehumidification performance was governed by the diffusion process. Water states and water distribution were investigated by molecular dynamics simulation. At low EDTMPA content (<10 wt.%), states of the water were not obviously changed and the increase of water diffusion coefficient was mainly attributed to enlarged free volume of the membrane. At high EDTMPA content (10–30 wt.%), the increase in the water diffusion coefficient mainly arose from the variations in the water states. Strong interaction between PVA and EDTMPA reduced the amount of water that bounded to the PVA and increased the proportion of free water. The diffusion coefficients of water increased with increasing proportion of free water, since the mobility of free water was higher than that of bound water. The permeance of water reached 997.7 GPU for the PVA–EDTMPA/PS membrane with a 20 wt.% EDTMPA content when the proportion of free water was the highest, and the separation factor increased to infinity.     

A recursive algorithm for the three-dimensional imaging of brain electric activity: Shrinking LORETA-FOCUSS

Estimation of intracranial electric activity from the scalp electroencephalogram (EEG) requires a solution to the EEG inverse problem, which is known as an ill-conditioned problem. In order to yield a unique solution, weighted minimum norm least square (MNLS) inverse methods are generally used. This paper proposes a recursive algorithm, termed Shrinking LORETA-FOCUSS, which combines and expands upon the central features of two well-known weighted MNLS methods: LORETA and FOCUSS. This recursive algorithm makes iterative adjustments to the solution space as well as the weighting matrix, thereby dramatically reducing the computation load, and increasing local source resolution. Simulations are conducted on a 3-shell spherical head model registered to the Talairach human brain atlas. A comparative study of four different inverse methods, standard Weighted Minimum Norm, L1-norm, LORETA-FOCUSS and Shrinking LORETA-FOCUSS are presented. The results demonstrate that Shrinking LORETA-FOCUSS is able to reconstruct a three-dimensional source distribution with smaller localization and energy errors compared to the other methods.     

压缩载荷作用下复合材料开孔补强稳定性分析

运用有限元软件MSC.Nastran分别分析了压缩载荷作用下的复合材料板在无孔、开孔及开孔补强后的稳定性问题.在开孔复合材料板稳定性分析中,讨论了开孔孔径和开孔位置的影响;在补强中,分别选取不同开孔孔径和开孔位置研究补强参数对板稳定性的影响.研究表明:开孔降低了复合材料板的稳定性,通过补强可提高其稳定性;开孔孔径和开孔位置对复合材料板稳定性的影响较大,补强参数随开孔孔径和开孔位置改变而改变,且对复合材料板的稳定性有所影响;补强后板的稳定性要好于无孔复合材料板的稳定性.     

An LC‐MS/MS method for determination of curculigoside with anti‐osteoporotic activity in rat plasma and application to a pharmacokinetic study

A rapid, simple, selective and sensitive LC‐MS/MS method was developed for the determination of curculigoside in rat plasma. The analytical procedure involves extraction of curculigoside and syringin (internal standard, IS) from rat plasma with a one‐step extraction method by protein precipitation. The chromatographic resolution was performed on an Agilent XDB‐C₁₈ column (4.6 × 50 mm, 5 µm) using an isocratic mobile phase of methanol with 0.1% formic acid and H₂O with 0.1% formic acid (45:55, v/v) at a flow rate of 0.35 mL/min with a total run time of 2.0 min. The assay was achieved under the multiple‐reaction monitoring mode using positive electrospray ionization. Method validation was performed according to US Food and Drug Administration guidelines and the results met the acceptance criteria. The calibration curve was linear over 4.00–4000 ng/mL (R = 0.9984) for curculigoside with a lower limit of quantification of 4.00 ng/mL in rat plasma. The intra‐ and inter‐day precisions and accuracies were 3.5–4.6 and 0.7–9.1%, in rat plasma, respectively. The validated LC‐MS/MS method was successfully applied to a pharmacokinetic study of curculigoside in rats after a single intravenous and oral administration of 3.2 and 32 mg/kg. The absolute bioavailability of curculigoside after oral administration was 1.27%. Copyright © 2013 John Wiley & Sons, Ltd.     

电阻率法在地基处理工程中的应用探讨

土的电阻率相关参数指标与土的工程力学指标紧密相连,并可反映土的一些特殊性质,如土的污染特征、地基液化特征等。本文首先简要介绍了土的电阻率理论,分析了土电阻率的室内外测试原理与方法。在归纳相关文献与工作的基础上,探讨土电阻率法在地基处理及其相关领域中的应用。深入分析了电阻率法在水泥土搅拌桩质量评价、地基处理效果评价、地基液化评判、压实土质量评价以及地基污染中的应用特征以及评价方法。并讨论了土的电阻率理论研究中存在的问题,展望了土电阻率理论的研究与应用前景。     

高阶非完整系力学中的交换关系

本文给出了高阶非完整系力学中的二种交换关系,证明了关于场方程和积分原理是等价的。     

A MOF Glass Membrane for Gas Separation

Metal–organic framework (MOF) glasses are promising candidates for membrane fabrication due to their significant porosity, the ease of processing, and most notably, the potential to eliminate the grain boundary that is unavoidable for polycrystalline MOF membranes. Herein, we developed a ZIF‐62 MOF glass membrane and exploited its intrinsic gas‐separation properties. The MOF glass membrane was fabricated by melt‐quenching treatment of an in situ solvothermally synthesized polycrystalline ZIF‐62 MOF membrane on a porous ceramic alumina support. The molten ZIF‐62 phase penetrated into the nanopores of the support and eliminated the formation of intercrystalline defects in the resultant glass membrane. The molecular sieving ability of the MOF membrane is remarkably enhanced via vitrification. The separation factors of the MOF glass membrane for H₂/CH₄, CO₂/N₂ and CO₂/CH₄ mixtures are 50.7, 34.5, and 36.6, respectively, far exceeding the Robeson upper bounds.     

模糊决策器的硬件实现

本文提出了一种硬件实现模糊决策的方法，从理论上论证了这种方法的正确性，并通过实验证明其可行。它可以应用于模糊硬件系统，以实现对连续或离散模糊信号的去模糊。