高级加密标准AES-192的7轮不可能差分分析

结合密钥扩展算法和划分子集的方法,提出7轮AES-192的不可能差分分析方法.首先估算猜测初始轮的错误密钥的最小概率;然后计算所需的明密文对的数量并选择明密文对,计算密文对的差分,猜测特殊的密钥字节对其进行不可能差分攻击.该攻击需要278选择明文,记忆存储空间为2129分组,以及约2155的7轮AES-192加密.与目前现有的结果相比,该攻击需要更少的选择明文数和较低的时间复杂度.

Crosslinkable poly (p-phenylenevinylene) derivative

To simplify the fabrication of multilayer light-emitting diodes, we prepared a p-phenylenevinylene-based polymer capped with crosslinkable styrene through a Wittig reaction. Insoluble poly(p-phenylenevinylene) derivative (PPVD) films were prepared by a thermal treatment. The photoluminescence and ultraviolet-visible (UV-vis) absorbance of crosslinked films and noncrosslinked films were studied. We also studied the solvent resistance of crosslinked PPV films with UV-vis absorption spectra and atomic force microscopy. Double-layer devices using crosslinked PPVD as an emitting layer, 2-(4-tert-butylphenyl)-5-phenyl-1,3,4-oxadiazole (PBD) in poly(methyl methacrylate) as an electron-transporting layer, and calcium as a cathode were fabricated. A maximum luminance efficiency of 0.70 cd/A and a maximum brightness of 740 cd/m(2) at 16 V were demonstrated. A 12-fold improvement in the luminance efficiency with respect to that of single-layer devices was realized.

略述浮游式海洋机器人的控制问题

本文探讨了海洋机器人的有关数学模型,坐标系的建立、描述方法、驱动方案、某些参数的闭环控制及其发展趋势等。 海洋资源是近三十年来许多国家争夺的主要对象。陆地资源的开发已有悠久历史,过去人类赖以生存的资源,主要来之于陆地。但陆地某些资源的开发和利用已接近尾声,据有关资料报导,陆地石油的开发可能只有几十年即将采尽。人类必须寻找新的资源产地,这就是海洋。那里有供几十亿人口生存的蛋白质和多种丰富的矿藏。 开发海洋有很大的难度,这个领域不适于人的直接生存,要想开发与征服海洋,必须借助于专用的工具,即海洋机器人。海洋深处的秘密人们还知道得很少,现正以各种技术手段进行探测。