牛顿与真理之海

 正值伯尔尼大学开始放假的7月下旬,哈勒(AdrianHaller)教授便飞往圣巴巴拉的加利福尼亚大学去参加一个会议。他提前离开伯尔尼是想途中在伦敦拜访几个朋友。在到达伦敦的当天,他抽空瞻仰了威斯敏斯特教堂里的艾萨克·牛顿(IsaacNewton)的陵墓。伫立在纪念碑前,哈勒阅读了这样的墓志铭:人们应该感谢那些生活在他们之中并为全人类增光的人。这句话表达了牛顿的英国同胞对他保持至今的崇敬和赞美。     

Z-连通连续偏序集的若干性质

对于Z-连通连续偏序集,证明了其上Z-连通Lawson拓扑空间是完全正则的,讨论了其可度量化的一个充分条件。更多还原     

Thermal Diffusivity of Film/Substrate Structures Characterized by Transient Thermal Grating Method

Transient thermal grating method is used to measure the thermal diffusivity of absorbing films deposited on transparent substrates. According to periodically modulated dielectric constant variations and thermoelastic deformations of the thin films caused by the transient thermal gratings, an improved optical diffraction theory is presented. In the experiment, the probing laser beam reflectively diffracted by the thermal grating is measured by a photomultiplier at different grating fringe spaces. The thermal diffusivity of the film can be evaluated by fitting the theoretical calculations of diffraction signals to the experimental measured data. The validity of the method is tested by measuring the thermal diffusivities of absorbing ZnO films deposited on glass substrates.