对计算机断层扫描技术中几个问题的探讨

本文对计算机断层扫描技术中所选择滤波函数的不同、射线束宽度的差异、探测器的响应、数据的采样及旋转中心的偏移等因素影响图像重建质量分别进行了讨论和分析。实验结果表明，这几个因素对重建后的图像质量产生的影响都是不可忽视的，尤其是在某些情况下，将会导致产生较大的误差。

Radiation Characteristics of Rectangular Patch Antennas with an Array of Pins

The patch antennas with an array of pins （pin array patch antennas） with excellent radiation characteristics are investigated for various substrate thicknesses. The radiation in the horizontal plane of a pin array patch antenna is very small compared to that of a conventional patch antenna. And the increase of forward radiation and the decrease of backward radiation of a pin array patch antenna are obtained than those conventional one＇s. Also the half-power beamwidth of E -plane radiation pattern of a pin array patch antenna is narrower compared to that of the conventional so that the directivity is improved.