The attractor—basin portrait of a cellular automaton

Local space-time structures, such as domains and the intervening dislocations, dominate a wide class of cellular automaton (CA) behavior. For such spatially-extended dynamics regular domains, vicinities, and attractors are introduced as organizing principles to identify the discretized analogs of attractors, basins, and separatrices: structures used in classifying dissipative continuous-state dynamical systems. We describe the attractor-basin portrait of nonlinear elementary CA rule 18, whose global dynamics is largely determined by a single regular attracting domain. The latter's basin is analyzed in terms of subbasin and portal structures associated with particle annihilation. The conclusion is that the computational complexity of such CA is more apparent than real. Transducer machines are constructed that automatically identify domain and dislocation structures in space-time, count the number of dislocations in a spatial pattern, and implement an isomorphism between rule 18 and rule 90. We use a transducer to trace dislocation trajectories, and confirm that in rule 18, isolated dislocation trajectories, as well as a dislocation gas, agree extremely well with the classical model of annihilating diffusive particles. The CA efficiently transforms randomness of an initial pattern ensemble into a random walk of dislocations in space-time.     

纳米Ni在77 K温度下压缩行为的研究

利用低温力学测试系统研究了电化学沉积纳米Ni在77 K温度下的压缩行为. 室温下纳米Ni 的屈服强度为 2.0 GPa, 77 K温度下的屈服强度为3.0 GPa, 压缩变形量则由室温的10%左右下降到5%. 借助应变速率敏感指数、激活体积、扫描电子显微和高分辨透射电子显微分析, 对纳米Ni的塑性变形机制进行了表征. 研究表明, 在77 K温度下的塑性变形主要是由晶界-位错协调变形主导, 晶界本征位错弓出后无阻碍地在晶粒内无位错区运动, 直至在相对晶界发生类似切割林位错行为. 同时分析了弓出位错的残留位错部分在协调塑性变形时起到的增加应变相容性和减小应力集中的作用. 利用晶界-位错协调机制和残留位错运动与温度及缺陷的相关性揭示了纳米Ni室温和77 K温度压缩性能差异的内在原因. 关键词： 塑性变形 强度 位错     

非结构子网格压力方法

纯拉氏流体力学计算失败的根源是砂漏运动和虚假涡旋,运用子网格拉氏质量与其相关的子网格密度得到子网格压力,子网格压力产生的扰动隅角力能消除这些虚假运动,以便消除困扰拉氏流体力学算法的网格畸变带来的数值计算困难.将包括子网格压力的相容流体算法推广到非结构网格,研制包括非结构子网格压力的相容流体程序,对Saltzman活塞问题进行数值模拟,从数值结果分析可知,非结构子网格压力方法能抑制虚假涡旋,消除砂漏畸变.     

Hyperbolic orbit and its variation of deep-space probe

While approaching the target body, the deep-space probe is orbiting hyperbolically before the maneuver. We discuss the variation of perturbed hyperbolic orbit using the method similar to that used in elliptic orbit. Ephemeris calculating and orbit control will benefit from the given analytical solution.     

强激光冲击铝合金改性处理研究

利用新型聚偏1.1-二氟乙烯（PVDF）压电传感器,实现了对激光引发的冲击波压力的实时测量,得到激光引发的冲击波峰压在铝中成指数型的衰减规律;观测了不同约束层材料在铝靶表面产生的激光冲击波,研究了不同约束层对冲击效果的影响;最后用激光冲击强化装置对7050-T7451航空铝合金结构材料进行了冲击强化处理,对试件激光冲击区存在的残余压应力及位错密度进行了测量。结果显示经激光冲击处理的试件表面具有极高的残余压应力,可达-200MPa以上。激光冲击处理后铝合金的位错密度得到显著的提高,疲劳寿命提高到175％～428％。这些重要结果对激光冲击改性处理技术的实际应用具有指导性作用。     

A field-sensitivity analysis of the relativistic motion of a single electron submitted to a perpendicular magnetic field

Sensitivity of the velocity of a single electron, in the relativistic case, to a perpendicular magnetic field is evaluated by defining a parameter which becomes useful in a number of cases related to dynamical systems. In particular, the ultrarelativistic case is examined.     

Brownian surfaces with boundary and Deligne cohomology

We define differentiable random surfaces, which realize a kind of generalized parallel transport for line bundles over the loop space. This gives a realization of one of the axioms of Segal of conformal field theory.     

Arytenoid Cartilage Dislocation: A 20-year Experience

SUMMARY: Arytenoid cartilage dislocation is an infrequently diagnosed cause of vocal fold immobility. Seventy-four cases have been reported in the literature to date. Intubation is the most common origin, followed by external laryngeal trauma. Decreased volume and breathiness are the most common presenting symptoms. We report on 63 patients with arytenoid cartilage dislocation treated by the senior author (RTS) since 1983. Significantly more posterior than anterior dislocations were represented. Although reestablishing joint mobility is difficult, endoscopic reduction should be considered to align the heights of the vocal processes. This process may result in significant voice improvement even long after the dislocation. Strobovideolaryngoscopy, laryngeal electromyography, and laryngeal computed tomography (CT) imaging are helpful in the evaluation of patients with vocal fold immobility to help distinguish arytenoid cartilage dislocation from vocal fold paralysis. Familiarity with signs and symptoms of arytenoid cartilage dislocation and current treatment techniques improves the chances for optimal therapeutic results.     

基于特征点匹配的电子稳像技术

为获得高质量视频输出序列,电子稳像技术常被用来去除成像设备所摄取的图像序列中的随机抖动。本文首先介绍了电子稳像的国内外发展现状。然后,从电子稳像技术中的运动估计模块出发,描述了国内外近年来出现的直接求取运动估计算法以及各种基于特征点匹配的运动估计方法,并对运动校正和运动补偿模块的算法进行了评述。最后综合分析了稳像算法的难点以及未来发展趋势,提出基于特征匹配的电子稳像技术的发展方向。     

联合梯度预测与导引滤波的图像运动模糊复原

针对由相机与所摄景物之间发生相对位置移动所导致的图像运动模糊,提出了一种鲁棒的基于单幅运动模糊图像的盲反卷积算法。该方法首先通过预测图像中的较强边缘信息,实现用简单、易于求解的优化问题在傅里叶域中快速、准确地估计出点扩散函数。然后利用得到的点扩散函数,使用基于梯度约束的非盲反卷积算法复原清晰图像,同时采用一种新的边缘保持滤波器-导引滤波来消除噪声并抑制振铃效应。实验结果表明：本文的算法能够快速地从单幅运动模糊图像复原出具有清晰边缘和纹理的高质量图像,并且运算时间不超过20 s。