采用多级技术的DBF雷达CCAB算法

数字波束形成算法中,CCAB算法在较高信干噪比条件下具有一定优势。但是计算时需要求逆矩阵,在阵元数较多的情形下运算量极大,很难实时实现,严重制约了其进一步的应用。提出了一种基于原有CCAB算法的多级计算方法,可以有效地减少运算量。实验表明,该方法虽然其信噪比性能比普通CCAB算法有所下降,但是仍能在干扰方向上形成较深的零陷并有效地抑制干扰,能够进一步应用于实际工程中。     

Sorption of Acid Green 25 on chitosan: Influence of experimental parameters on uptake kinetics and sorption isotherms

Acid Green 25, which is a diazoic dye bearing two sulfonic groups, is efficiently sorbed on chitosan. The protonation of chitosan may explain the electrostatic attraction of this anionic dye and that its optimum pH is close to 3. Preliminary protonation of amine groups (obtained by contact with a sulfuric acid solution) reduced the variation of solution pH following sorbent addition but significantly reduced sorption performance: the maximum sorption capacity of raw chitosan, 525 mg dye/g (0.84 mmol dye/g), was halved by acidic preconditioning. The acidic conditioning also reduced the kinetic rate—the time necessary to reach equilibrium increased up to threefold depending on the experimental conditions. The size of sorbent particles influenced sorption kinetics and equilibrium because of resistance to intraparticle diffusion, but the sorption appeared to occur not only at the surface of the sorbent but also in the intraparticle network of the polymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1073–1080, 2003     

纯镁对碳化硼颗粒的常压浸渗

本文研究了纯镁对不同致密度的碳化硼(B₄C)颗粒基片的常压浸渗性;讨论了镁液对B₄C颗粒聚集体常压浸渗的影响因素;提出了浸渗模型。研究表明,纯镁在氩气保护下,800～850℃温度范围保温30min即可浸渗B₄C颗粒聚集体。浸渗深度和宽度随加热温度升高和保温时间延长而增加;常压浸渗的B₄C_P/Mg复合材料具有很高的硬度,B₄C颗粒在基体中分布较均匀。     

腐蚀算法在重建一类特殊管道中的应用

针对一类特殊而不能直接对其观察的管道（如动物的血管），为了准确了解其内部特征和形态，借助计算机给出了一种用腐蚀算法来重建管道原形的方法。这种方法简单易行，而且精确度高。     

Data fitting with a spline using a real-coded genetic algorithm

To obtain a good approximation for data fitting with a spline, frequently we have to deal with knots as variables. The problem to be solved then becomes a continuous nonlinear and multivariate optimization problem with many local optima. Therefore, it is difficult to obtain the global optimum. In this paper, we propose a method for solving this problem by using a real-coded genetic algorithm. Our method can treat not only data with a smooth underlying function, but also data with an underlying function having discontinuous points and/or cusps. We search for the best model among candidate models by using the Bayes Information Criterion (BIC). With this, we can appropriately determine the number and locations of knots automatically and simultaneously. Five examples of data fitting are given to show the performance of our method.     

钼精矿结球机理及对策研究

钼精矿产品质量的提高、粒度变细,干燥过程中结球现象严重。在氧化钼的焙烧过程中MoS2残留量较高。本文针对这一现象,分析了其结球机理,提出了相应对策及解决办法。     

正交多项式的并行算法修正及其稳定性分析

通过修正求解Chebyshev多项式的Clenshaw和Forsythe算法。提出了求解一般正交多项式的两种并行算法。并通过讨论这两种并行算法矩阵形式的舍入误差，对它们的稳定性进行了分析。     

基于约束优化的联想记忆模型学习算法

本文提出了一种对称互连神经元网络的学习策略,利用全局约束优化方法确定连接权。优化过程采用了梯度下降技术。这种学习算法可以保证训练样本成为系统的稳定吸引子,并且具有优化意义上的最大吸引域。本文讨论了网络的存储容量,训练样本的渐近稳定性和吸引域大小。计算机实验结果说明了学习算法的优越性。     

TEMIC射频卡的速率自适应读卡算法

提出种基于TEMIC射频卡Manchester编码的速率自适应读卡算法,并对该算法进行了说明和示例。     

Bi3+对纳米MnO2水热合成的影响研究

在中性和酸性条件下，以MnO2作为锰源，通过水热合成了纳米MnO2，通过XRD和TEM对产物进行的观察表明，在酸性条件下，向溶液中添加一定量的Bi^3 ，产物的晶型由α型向γ型转化，产物形貌由针状、丝状向颗粒状转变。