电磁辐射的最小方向性探索

本文讨论电磁场辐射的最小方向性。由于Maxwell体系不存在各向同性解,因此电磁辐射不可能做到无方向性。然而,大量的通信,应用实践又给我们提出希望这样的逼近目标。于是,自然成了必须接受并研究的一个矛盾课题。这就构成了本文的核心内容。

基于方向性全变分Retinex的低照度图像增强

为了提高低照度图像的视觉质量,提出一种基于方向性全变分Retinex的低照度图像增强方法.首先利用基于灰像素的色彩恒常方法恢复低照度图像的真实场景颜色;然后构造方向性相对全变分约束,据此估计照度图像;接着在计算反射图像时,利用方向性梯度残余最小约束来遏制增强过程中放大的噪声和伪影;最后根据当前像素亮度与其邻域平均亮度的关系拉伸局部亮度,得到最终的增强结果.采用从互联网上搜集的多幅低照度图像进行实验,结果表明,与一些当前国际先进水平的方法相比,文中方法得到的图像质量更佳、视觉效果更好.

论电磁惯性

伟大的物理学家牛顿首先提出了力学惯性定律:"每个物体将继续保持其静止或沿一直线做匀速运动状态,除非有力加于其上迫使它改变它改变这种状态。"而本文则在电磁领域提出相应的电磁惯性——每个电磁波都倾向于保持球三维或圆二维状态向外传播,除非有外加源或边界迫使它改变这种状态。文中,还把这一思想进一步扩展为电位φ和电荷σ的静电惯性。

A study of particles penetration in sieving process on a linear vibration screen

This paper presented an investigation of particle collision and penetration using the discrete element method to understand the motion of particles and improve theoretical treatment in the sieving process. The process progressively was divided into looseness, stratification, collision, and penetration. Particle penetration has a direct effect on the screening performance. The penetration probability was defined, and the mathematical relationships between particle penetration and vibration parameters were established using the least squares method. To obtain the ideal penetration probability for materials the amplitude and frequency should preferably be near 3.0 mm and 25 Hz, respectively. The vibration direction angle has only a slight effect on penetration. The stage of the screening process from 0.1 to 0.7 s is the primary region for collision and penetration. This paper focused on the sieving process to more fully understand how particle collision and penetration influence the screening efficiency.