Invariance of the stationary distribution of states of networks with multimode service, different types of requests, and discriminatory processor sharing

Open and closed queuing networks with multimode strategies and several types of requests are studied. Single-line nodes can operate in several modes. The time spent in each mode has an exponential distribution. The queuing discipline of the server is the discriminatory processor sharing (DPS). The number of requests is a random variable with an arbitrary distribution function. The invariance is established of the stationary distribution of the probabilities of the network states with respect to the functional form of the distributions of the work required to service the requests.     

Nucleation of CdTe islands during synthesis from the vapor phase on a cooled substrate

The results of structural studies of nucleation mechanisms of CdTe islands on a substrate cooled to a temperature as low as 77 K are reported. Condensation curves, distribution functions, and microphotographs are presented. A model satisfactorily interpreting the revealed experimental facts from the point of view of nucleation of three-dimensional islands on a polymolecular adsorbate layer due to the relaxation of its chemical energy is suggested.     

功率模块的封装和“一体化”封装——针对可再生能源和电动交通工具

如今的风力发电和电动汽车市场需要具有高功率密度的功率模块、高可靠性以及高的机械、热和电气强度。无焊接压接技术最符合这些要求。下一步,键合线将被弹性金属薄片取代,以克服目前在功率循环疲劳方面的限制。通过将这些技术用于功率模块和这些模块的一体化封装以及通过机械一体化设计嵌入式系统能够实现功率密度方面的卓越性能。     

天线方向图包络要求的发展趋势

本文简述了卫星通信地球站天线方面图包络指标要求的发展,重点论述了当前的发展趋势,同时对几个基本概念进行了说明,对从事卫星通信总体,特别是对从事该类天线技术研制方面有一定参考价值。