分时电表表盘数字读数的自动识别系统

(研究了分时电表表盘数字的自动识别,它是电表误差分析系统的关键所在。识别工作包括平段和谷段整数和小数数字的识别,难点在于刻度轴歪斜、半个字符的识别,以及刻度对应的小数值的推算。该文构建了一个完整的分时电表表盘数字自动识别系统。该系统以二值化、投影算法、开闭运算、边缘提取、Hough变换等一系列算法作为预处理,提出了整字和非整字两种识别算法。针对300帧现场采集的电表图像,该系统获得了单字正确识别率99.8%和整表正确识别率97.3%的结果,表明该系统具有较强的鲁棒性。

“算账”三例(初二、初三)

从生活走向物理,从物理走向社会.随着课程改革的不断深入,中考试题越来越贴近生活,更加注重解决实际问题的能力.经济类试题就是运用所学知识.通过分析、计算来解决现实生活中的经济支出、可行性论证等问题.

A Surface Femtosecond Two-Photon Photoemission Spectrometer for Excited Electron Dynamics and Time-Dependent Photochemical Kinetics

A surface femtosecond two-photon photoemission （2PPE） spectrometer devoted to the study of ultrafast excited electron dynamics and photochemical kinetics on metal and metal oxide surfaces has been constructed. Low energy photoelectrons are measured using a hemispherical electron energy analyzer with an imaging detector that allows us to detect the energy and the angular distributions of the photoelectrons simultaneously. A Mach-Zehnder interferom- eter was built for the time-resolved 2PPE （TR-2PPE） measurement to study ultrafast surface excited electron dynamics, which was demonstrated on the Cu（111） surface. A scheme for measuring time-dependent 2PPE （TD-2PPE） spectra has also been developed for studies of surface photochemistry. This technique has been applied to a preliminary study on the photochemical kinetics on ethanol/TiO2（110）. We have also shown that the ultrafast dynamics of photoinduced surface excited resonances can be investigated in a reliable way by combining the TR-2PPE and TD-2PPE techniques.