Effect of thermal aging on the defectiveness of thermostable aromatic arimid and togilen fibres

The effect of thermal aging in air on the defectiveness of thermostable heteroaromatic Arimid-T and Togilen fibres was investigated based on the change in the scale dependences and coefficients of variation of the breaking characteristics: strength, elongation at break, and arbitrary deformation energy to break. The change in the scale dependences and scale coefficients of the deformation characteristics (elongation and deformation energy to break) more significantly and objectively reflect the increase in the defectiveness of thermostable fibres during thermal aging than the change in the scale dependences and scale coefficients of the strength and the coefficients of variation of the breaking characteristics. In thermal aging, the change in the defectiveness of Arimid-T fibres is smaller than for Togilen fibres. The data obtained indicate the elevated workability of thermostable heteroaromatic fibres at temperatures of 300°C: 300 h and more for Arimid-T fibres and up to 100 h for Togilen fibres.St. Petersburg State University of Design and Technology. Translated from Khimicheskie Volokna, No. 3, pp. 27–30, May–June, 1995.     

交通网络弹复度与易碎度的测算与分析

弹复性是系统在失效或被破坏之后能够恢复正常工作的能力.弹复性工程是当今国际上研究的热点.本文提出了基于节点对间的独立路径可靠度和交通网络的弹复度的定量测算方法,提出了反映节点和路段对交通网络影响大小的易碎性的概念和测算方法.论文还就弹复度和易碎度的几个相关性质提出了几个重要定理.针对我国的铁路网络,计算了所有节点城市和路段的弹复度和易碎度,并对弹复度和易碎度高的节点的分布规律进行了探讨,得出了一些有益的结论.     

Outage probability analysis for superposition coded symmetric relaying

Superposition coded symmetric relaying is a bandwidth-efficient cooperative scheme where each source node simultaneously transmits both its own local packet and relay packet that originated at its partner by adding the modulated local and relay signals in Euclidean space. This paper investigates the power allocation and outage probability of a superposition coded symmetric relaying system with finite-constellation signaling. We first derive the mutual information (MI) metrics for the system. The derived MI metrics consist of two parts: one represents the MI conveyed by the modulated signal corresponding to its own data, and the other represents the MI conveyed by the modulated signal corresponding to its partner’s data. Using MI based effective signal-to-noise ratio mapping technique, we attain expressions for the outage probability. Furthermore, we discuss power allocation policies that minimize the outage probability. Simulation results are presented to verify the correctness of the outage probability analysis and the benefits of the power allocation.