A digital secure image communication scheme based on the chaotic Chebyshev map

In this paper, a simple image secure communication scheme based on the chaotic Chebyshev map and chaos synchronization is proposed. The scheme relies on the excellent correlation property of chaotic sequences, which is very desirable for secure image communication. The results obtained by computer simulation indicate that the transmitted source image can be correctly and reliably recovered using the proposed scheme, even through a noisy channel. Notably, the scheme possesses relatively high security and can be easily implemented. Moreover, the quality of the recovered image is satisfactory, quantified by such common criteria as the bit‐error rate performance. Copyright © 2004 John Wiley & Sons, Ltd.     

Chemical modification of genetic damage from continuous irradiation in mice

It has been demonstrated that Adeturon (S-2-aminoethyl-iso-thiuronium adenosine triphosphate) showed a marked protective effect against translocations induction in mice germ cells after chronic gamma-or neutron-irradiation.     

封闭水循环的发展前景

近年来，新纸机的设计车速成倍增加。随着对纸产品质量要求的提高和对二次纤维利用的增加，对过程中水的质量要求也就更高。     

A model study of a conventional fixed bed tubular reactor with a catalyst layer on the inside tube wall

Mathematical simulation of a novel design of tubular reactor, supplied with a conventional fixed bed of catalyst and a catalyst layer on the inside tube wall, is carried out. The oxidation process of o-xylene to phthalic anhydride is investigated, using the kinetics of Calderbank and co-workers. In comparison with the conventional fixed bed reactor the new design displays several advantages, namely: higher productivity, better selectivity, relieved temperature regime, longer catalyst life, and shorter tubes.     

A new product distribution formulation for fischer-Tropsch synthesis. Effect of metal crystallite size distribution

A new product distribution formulation is presented for Fischer-Tropsch synthesis (FTS). This formulation, which contains the effect of the metal crystallite size on the product selectivity, can explain all possible Fischer-Tropsch product distributions. The Anderson-Shulz-Flory distribution formulation can be regarded as its approximation in special cases.     

海上油田电脱分离器结构设计研究

作为原油净化处理的关键步骤,电脱分离效果的好坏直接决定原油能否达到深加工或销售的要求。对电脱分离器的机理和结构进行了详细分析,并针对海上油田的特殊工况,提出了设计海上油田电脱分离器时应考虑的因素和设计方法。     

数字滤波器的两个理论公式及其应用

本文从傅里叶变换理论和随机过程理论出发,导出描述数字滤波器性质的两个公式,称之为滤波器的频谱窗和滤波器的嗓声压缩程度,并应用这两个公式对工程技术领城中常用的二项式滤波和最小二乘滤波进行了分析比较。     

关于先张法温差损失的探讨

我国混凝土结构设计规范（GBJ－89）对先张法预应力混凝土构件进行蒸汽养护时的温差损失，有明确的计算方法。从考虑钢筋和混凝土之间的线温度膨胀系数关系入手，对该项损失提出了不同的看法，供参考讨论。     

滚子齿式空间分度凸轮机构的研究

本文以微分几何和空间旋转矩阵算子理论为数学工具,应用空间曲面啮合原理,对滚子齿式空间分度凸轮机构进行了系统的研究。推导了凸轮轮廓曲面方程、啮合方程和压力角计算公式,并对凸轮曲面的曲率进行了分析,给出了主曲率、诱导主曲率等一系列计算公式,最后给出了凸轮工作曲面产生根切的判别条件。