The formation energies and the equilibrium concentration of vacancies, interstitial H, K, P, O and antisite structural defects with P and K in KH2PO4 （KDP） crystals are investigated by ab initio total-energy calcula...The formation energies and the equilibrium concentration of vacancies, interstitial H, K, P, O and antisite structural defects with P and K in KH2PO4 （KDP） crystals are investigated by ab initio total-energy calculations. The formation energy of interstitial H is calculated to be about 2.06 eV and we suggest that it may be the dominant defect in KDP crystal. The formation energy of an O vacancy （5.25 eV） is much higher than that of interstitial O （0.60 eV）. Optical absorption centres can be induced by defects of O vacancies, interstitial O and interstitial H. We suggest that these defects may be responsible for the lowering of the damage threshold of the KDP. A K vacancy defect may increase the ionic conductivity and therefore the laser-induced damage threshold decreases.展开更多
零售业是生活中常见的行业，在零售业中引入了电子收款机系统（Point of Sells，POS）即进销存管理系统，是商店经营中的最热门的话题之一。这种进销存管理系统一般是现在比较常见的客户端／服务器模式也即C／S模式。文章介绍了采用INSP...零售业是生活中常见的行业，在零售业中引入了电子收款机系统（Point of Sells，POS）即进销存管理系统，是商店经营中的最热门的话题之一。这种进销存管理系统一般是现在比较常见的客户端／服务器模式也即C／S模式。文章介绍了采用INSPRISE公司的DELPHI7.0开发工具结合SQL SERVER2000数据库服务器。首先在短时间内建立系统应用原型，然后，对初始原型系统进行需求更迭，不断修正和改进，直到形成用户满意的可行系统。展开更多
基金Project supported by the Program for New Century Excellent Talents at the University of China (Grant No.NCET-08-0722)
文摘The formation energies and the equilibrium concentration of vacancies, interstitial H, K, P, O and antisite structural defects with P and K in KH2PO4 （KDP） crystals are investigated by ab initio total-energy calculations. The formation energy of interstitial H is calculated to be about 2.06 eV and we suggest that it may be the dominant defect in KDP crystal. The formation energy of an O vacancy （5.25 eV） is much higher than that of interstitial O （0.60 eV）. Optical absorption centres can be induced by defects of O vacancies, interstitial O and interstitial H. We suggest that these defects may be responsible for the lowering of the damage threshold of the KDP. A K vacancy defect may increase the ionic conductivity and therefore the laser-induced damage threshold decreases.
文摘零售业是生活中常见的行业，在零售业中引入了电子收款机系统（Point of Sells，POS）即进销存管理系统，是商店经营中的最热门的话题之一。这种进销存管理系统一般是现在比较常见的客户端／服务器模式也即C／S模式。文章介绍了采用INSPRISE公司的DELPHI7.0开发工具结合SQL SERVER2000数据库服务器。首先在短时间内建立系统应用原型，然后，对初始原型系统进行需求更迭，不断修正和改进，直到形成用户满意的可行系统。
