基于背景运动补偿的红外目标运动分析

 介绍了基于运动补偿的红外目标运动分析方法。阐述了运动补偿的必要性、过程原理和实现方法，并用之于对红外运动目标的视频跟踪，通过用背景运动量补偿目标的相对运动量，得到明确而直观的目标运动轨迹，有效地揭示了目标运动的内在规律，为红外目标的轨迹预测与跟踪提供了更有效的分析依据。     

An Exact Evolution Equation of the Curvature Perturbation for Closed Universe

As is well known, the exact evolution equation of the curvature perturbation plays a very important role in investigation of the inflaorresponding exacttion power spectrum of the flat universe. However, the c extension for the non-flat universes has not yet been given clearly. Interest in the non-flat, specially closed, universes has been aroused recently. The need for this extension is pressing. We start with the most elementary physical consideration and obtain finally this exact evolution equation of the curvature perturbation for the non-flat universes, as well as the evolutionary controlling parameter and the exact expression of the variable mass in this equation. We approximately perform a primitive and immature analysis on the power spectrum of non-flat universes. This analysis shows that the exact evolution equation of the curvature perturbation for the non-flat universes is very complicated, and we need to carry out many numerical and analytic works for this new equation in the future to judge whether the universe is fiat or closed by comparison of theories with observations.     

Aggregation on heterogeneous surface

Chessboard-like substrates are introduced in this paper, in order to study the diffusion-limited aggregation (DLA)and the motion of poly-atoms on heterogeneous surfaces. The effect of morphology of such substrates upon the cluster aggregation is investigated using the Monte Carlo simulation. It is found that the growth process and the cluster morphology are governed by the energetic topography of the substrates. Our simulation also indicate that the island density and the fractal dimension of the clusters depend strongly on the substrate topography and the activation energy.     

双脉冲星的发现

来自英国、澳大利亚、意大利和美国的天文学家首次发现了双脉冲星.这一发现可用于检验广义相对论,并使研究脉冲星的磁气圈成为可能(有关论文见LyneGetal.Science express,2 0 0 4 ,1 0 94 6 4 5 ) .脉冲星是密度极高的中子星,比地球的质量大一百万倍,而直径仅为几十公里.脉冲星     

滚动演示实验

介绍了滚动演示实验教具的制作和使用方法，并利用质心运动定理和转动定理解释了演示现象。     

微液滴在仿蛛丝结构TiO2纤维表面的定向运动与粘附

制备了具有响应性的仿蛛丝周期纺锤节TiO₂纤维。通过改变纤维表面微观结构、紫外光照和超声波等手段,仿蛛丝结构TiO₂纤维表面浸润性会发生响应性变化。纤维表面的这种浸润性变化,不仅实现了水滴从纺锤节两端到中心处的定向运动,而且可以使得水滴被纤维纺锤节粘附。当仿蛛丝结构TiO₂纤维表面为亲水状态时,无论纺锤节光滑还是粗糙,水都是从纺锤节两端向中心方向运动;当仿蛛丝TiO₂纤维表面疏水时,水滴会被具有粗糙表面的纺锤节两端粘附。     

AP化学课程内容修订的重要资讯

美国的AP课程即将迎来新一轮的修订,其课程内容和考试形式即将发生重大变化。本文介绍了修订后的AP课程内容的主题框架和每个主题所删去的知识点。     

软机器人的运动行为研究进展

软机器人的出现不仅弥补了传统机器人的缺点,并逐渐成为机器人领域的热点和前沿之一,近年来该领域研究进展十分迅速。本文总结了典型软机器人的运动行为的研究进展,介绍了软机器人按材质类型的分类(包括液晶软机器人、生物分子软机器人、PDMS软机器人、液体软机器人和自振荡凝胶软机器人)及其功能和潜在应用,讨论了当前不同类别软机器人运动的特点和存在的问题,在此基础上展望了软机器人领域面临的机遇、挑战和未来发展方向。     

运动对去卵巢大鼠骨元素代谢的影响

用测定骨元素含量的方法，分析了运动对正常大鼠和切除双侧卵巢后的大鼠骨元素代谢的影响。将健康4个月龄雌性SD大鼠44只随机分成5组：（1）非去势非运动组；（2）非去势＋运动组；（3）假去势非运动组；（4）去势非运动组；（5）去势＋运动组。运动组用大鼠专用跑台中等运动强度训练，持续10周。结果表明，去卵巢大鼠骨Ca,Mg,S,Mn,Zn等含量显著降低，P含量显著增加。运动训练可使去卵巢大鼠降低的骨Ca,Mg,S,Mn,Zn等含量显著回升，骨P含量显著回降。提示中等强度运动训练可对抗由于去卵巢所引起的骨元素代谢紊乱。