贵州广播电台技术中心电源系统改造

通过对贵州人民广播电台技术中心电源系统改造工程的介绍，对于如何通过系统设计和规划施工，建设一个安全可靠、经济适用的供电系统提供了一个较为完备的解决方案。     

Resolution and contrast enhancement in optical sub-traction microscopy with annular aperture

A method for improving lateral resolution and reducing imaging distortion of optical subtraction microscopy is proposed. First, an azimuthally polarized (AP) light is modulated by an annular aperture. Then, an image with higher lateral resolu-tion is obtained by subtracting an image obtained by an annular AP beam from an image obtained by a radially polarized beam. The simulation results demonstrate that compared with the case without the annular aperture, negative side-lobes in the effective point spread function are effectively suppressed, and the imaging quality of subtraction microscopy is obvi-ously enhanced.