手指静脉认证系统的算法研究

提出一整套手指静脉认证系统的图像处理和静脉模板匹配算法.算法采用Sobel算子结合首遇跟踪法检测手指边缘,然后采用最小均方误差原则拟合手指边缘并对图像进行旋转校正归一化;基于最大曲率模型的思想,采用四个方向梯度算子提取静脉;为降低拒真率和提高匹配速度,对静脉图像进行膨胀、三值化和两次压缩,建立包含静脉、背景和模糊区的紧...     

PROJECTION MODULUS: A NEW DIRECTION FOR SELECTING SUBSET AUTOREGRESSIVE MODELS

Selecting a parsimonious subset autoregressive time series model is a valuable objective particularly where there is or may be evidence that a time series may have some form of periodic or quasi-periodic behaviour. An efficient model selection procedure is essential because of the large number of possible alternative models involved. The explanation of an increase in residual variance due to excluding a lag is examined in Hilbert space. As a result, a new statistic, the projection modulus , and its derivatives are developed to assess the significance of any lag in a model. The impact of deleting a lag, as measured by these statistics, helps to produce a selection procedure where true lags have less chance of being removed. We then assess an efficient subset autoregressive model selection procedure employing these statistics. The success of the proposed procedure is illustrated by its efficiency in identifying the true model for simulated and real data.     

自蔓延高温合成（SHS）过程的点火模型与分析

基于热力学原理，提出了一个分析自蔓延反应中点火过程的模型，并推出了一个简单，直观的点火公式。认为燃烧合成的自动蔓延过程是样品中一层一层的逐层点火过程，因此，点公式也可以用来解释自蔓高温合成过程本身。对ＮｉＡｌ和ＴｉＢ２等的点火过程实际研究表明，理论模型有一定的指导意义。     

Biodegradation of phenol in the presence of heavy metals

A microbial growth model was presented for estimating the dynamic behavior of cell growth and substrate consumption in the biodegradation of phenol containing a heavy metal, such as zinc or copper ions. The application of the model for experiments in a batch culture and a continuous culture was examined. The values calculated according to the model corresponded satisfactorily with experimental data, such as the optical density of cells and the concentration of phenol. Using the model, the stability of steady states in a continuous culture was analytically evaluated based on the eigenvalues. The steady states were separated into three categories: (i) a stable steady state where phenol was consumed, (ii) an unstable steady state where phenol was consumed, and (iii) a washout state where phenol was not consumed. The number, kind, and stability of steady states varied significantly with operational conditions such as dilution rate, feed concentration of phenol, and feed concentration of heavy metal ions. The operational conditions required to obtain the stable steady state where phenol was consumed are shown graphically. © 2000 Society of Chemical Industry     

Bd／St乳液共聚合反应数学模型──I动力学数学模型

以Ｓｍｉｔｈ－Ｅｗａｒｔ乳聚理论为基础，建立了Ｂｄ／Ｓｔ浮液共聚合生产Ｅ—ＳＢＲ的动力学数学模型。并根据过程的稳态和动态特性，分别建立了稳态和动态动力学数学模型。模型中全面考查了由于化学反应和流入、流出等对体系中各组份的浓度、乳胶粒总数和粒径分布、转化率等过程状态的影响。     

Gas permeability and mechanical properties of polystyrene–polypropylene blends

Permeability to water vapor and oxygen, elastic modulus, tensile strength, and impact strength of polystyrene–polypropylene and high-impact polystyrene–polypropylene blends were determined as functions of blend composition and morphology. Three types of styrene–butadiene block copolymers were tested as compatibilizers and found to improve mechanical properties of blends. The experimental data on permeability and modulus were compared with the predictions for the studied binary and ternary blends. The predictive scheme employs a two-parameter equivalent box model and the data on phase continuity of constituents calculated using general equations derived from percolation theory. Blends with decreased permeability and plausible mechanical properties were proposed with regard to intended applications in food packaging. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 69: 2615–2623, 1998     

颗粒多孔表面强化沸腾传热动力学研究

通过对颗粒多孔层几何结构、沸腾两相流及传热的理论分析，提出了微型通道薄膜环状蒸发物理模型和沸腾传热机理，建立了颗粒多孔表面强化沸腾传热动力学模型。该动力学模型与实验数据吻合良好，可用于工程设计。     

不同粒径固体颗粒的悬浮速度计算及测试

分析讨论了不同粒径固体颗粒群的料浆流体力学特性，并在模型反应器中对其悬浮速度进行了实验测量。结果表明，以粒径范围为判据判定颗粒周围流场的流态，可使悬浮速度的测量、研究变得更简单、准确。研究采用悬浮分级模型，提高了悬浮速度的分析计算精度     

煤液化过程中溶剂的作用

综述了近年关于煤液化反应中溶剂作用方面的研究成果，以及研究溶剂作用的新分析手段和研究方法。     

二维参数化图形技术研究进展

近几年来，参数化图形技术得到了不断的发展。目前已有多种参数化图形方法及系统。这些参数化图形方法可分为３种，即变分几何法、几何推理法和过程法。主要介绍这３种方法的研究进展。