A Theoretical Method for Estimating Performance of Reed-Solomon Codes Concatenated with Orthogonal Space-Time Block Codes

1　ＩｎｔｒｏｄｕｃｔｉｏｎＲｅｃｅｎｔｌｙ,ａｎｅｗｓｐａｃｅ ｔｉｍｅｃｏｄｅａｄａｐｔｅｄｔｏｍｕｌｔｉｐｌｅａｎｔｅｎｎａｓｗｉｒｅｌｅｓｓｆａｄｉｎｇｃｈａｎｎｅｌｈａｓｂｅｅｎｐｒｏｐｏｓｅｄ[1～6] .Ｔｈｅｃｏｄｅｓａｒｅｔｈｅｊｏｉｎｔｄｅｓｉｇｎｏｆｃｏｄｉｎｇ ,ｍｏｄｕｌａｔｉｏｎ ,ｔｒａｎｓｍｉｓｓｉｏｎａｎｄｒｅｃｅｐｔｉｏｎｄｉ ｖｅｒｓｉｔｙｔｏ ｐｒｏｖｉｄｅｔｈｅｂｅｓｔｔｒａｄｅｏｆｆｂｅｔｗｅｅｎｄａｔａｒａｔｅｓ,ｄｉｖｅｒｓｉｔｙａｄｖａｎｔａｇｅａｎｄｃｏｄｅｓ…     

Research on the Safety Evaluation of a High-pressure Vessel in a Missile System

In reference[1], we measured fracture properties of raw material, weld seam and heat-affected zone of high-pressure vessels(HPV); in this paper, we carried out safety evaluation on the basis of the previous work and predicted the lifetime of in-service vessels with flaw by use of the fracture criterion for model Ⅰ crack in fracture mechanics. This method reduced the artificial error and the ultrasonic testing operator‘s work burden. The experimental and theoretical bases for the defect assessment of military HPV were established.     

SCGM(1,m)_c model with time-lag and its application in deformation analysis

ＴｈｅｃｒｉｔｉｃａｌｐｒｏｂｌｅｍｓｉｎＧｒｅｙｓｙｓｔｅｍｓａｒｅｍｏｄｅｌｉｎｇａｎｄｐｒｅｄｉｃｔｉｏｎ .Ｔｈｒｏｕｇｈｇｅｎｅｒａｔｉｏｎｔｒａｎ ｓｉｔｉｏｎａｎｄｃｏｒｒｅｌａｔｉｏｎａｎａｌｙｓｉｓｔｅｃｈｎｉｑｕｅｓ,ｇｒｅｙｓｙｓｔｅｍｔｈｅｏｒｙｐｒｏｐｏｓｅｄｉｎ 1 982ｂｅｃｏｍｅｓａｎｕｓｅｆｕｌｔｏｏｌｆｏｒｉｎｖｅｓｔｉｇａｔｉｎｇｅｖｏｌｕｔｉｏｎｍｅｃｈａｎｉｓｍｓａｎｄｄｅ ｖｅｌｏｐｉｎｇｐｒｅｄｉｃｔｉｏｎｍｏｄｅｌｓｆｏｒｔｈａｔｋｉｎｄｏｆｓｙｓ ｔｅｍｓ…     

AERATION EFFECT OF SUBMERGED JET ON HYDRAULIC CHARACTERISTICS

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＪｅｔｆｌｏｗｈａｓｂｅｅｎｅｘｔｅｎｓｉｖｅｌｙａｐｐｌｉｅｄｆｏｒｅｎｅｒｇｙｄｉｓｓｉｐａｔｉｏｎ .Ｉｎｄｅｓｉｇｎ ,ｈｏｗｅｖｅｒ,ｂｅｃａｕｓｅｏｆｔｈｅｃｏｍ ｐｌｅｘｉｔｙｏｆｐｒｏｂｌｅｍａｎｄｔｈｅｄｉｆｆｉｃ     

Knowledge Processing Method of Fault Diagnosis Expert Systems for Letter Sorting Equipment

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｉｎｍａｉｌｃｅｎｔｅｒｓ,ｔｈｅＯＶＣＳｌｅｔｔｅｒｓｏｒｔｉｎｇｍａ ｃｈｉｎｅ ,ａｎｉｎｔｅｇｒａｔｅｄｉｎｃｏｒｐｏｒａｔｉｏｎｏｆｍｅｃｈａｎｉｓｍ ,ｅｌｅｃｔｒｉｃｉｔｙａｎｄｏｐｔｉｃｓ,ｐｌａｙｓａｋｅｙｒｏｌｅｉｎｔｈｅｐｒｏ ｃｅｓｓｉｎｇｏｆｌｅｔｔｅｒｓ.Ｈｏｗｅｖｅｒ ,ｔｈｅｖａｒｉｅｔｉｅｓａｎｄｆｒｅ ｑｕｅｎｃｉｅｓｏｆｆａｕｌｔｏｃｃｕｒｒｅｎｃｅｓａｒｅｉｎｃｒｅａｓｉｎｇｗｉｔｈｔｈｅｌａｓｔｉｎｇｓｅｒｖｉｃｅ.Ｔｈｅｄｉｆｆｅｒｅ…     

电力系统暂态摇摆曲线的分群

采用模式分类的方法对摇摆曲线分群,先采用零相称低通滤波器和快速傅里叶变换对曲线预处理,然后进行了特征抽取,利用一个基于规则的简单的专家系统对特征集分类以得到与专家经验相符的结果。     

Effect of Niobium on Isothermal Transformation of Austenite to Ferrite in HSLA LowCarbon Steel

Using thermomechanical simulation experiment, the kinetics of the isothermal transformation of austenite to ferrite in two HSLA lowcarbon steels containing different amounts of niobium was investigated under the conditions of both deformation and undeformation. The results of optical microstructure observation and quantitative metallography analysis showed that the kinetics of the isothermal transformation of austenite to ferrite in lower niobium steel with and without deformation suggests a stage mechanism, wherein there exists a linear relationship between the logarithms of holding time and ferrite volume fraction according to Avrami equation, whereas the isothermal transformation of austenite to ferrite in high niobium steel proceeds via a two stage mechanism according to micrographs, wherein, the nucleation rate of ferrite in the initial stage of transformation is low, and in the second stage, the rate of transformation is high and the transformation of residual austenite to ferrite is rapidly complete. Using carbon extraction replica TEM, niobium carbide precipitation for different holding time was investigated and the results suggested that NbC precipitation and the presence of solute niobium would influence the transformation of austenite to ferrite. The mechanism of the effect of niobium on the isothermal transformation was discussed.     

An Analysis of the Service Structure of China Post

Thepostalservicestructurereferstothestatus,whichisoftenrepresentedbytheproportionofacertainserviceamongthewholerevenues,andtherelationshipofvariouspostalserviceswithinthecon textoftheservicestructure.Thechangingpostalenvironmentleadstosomechangesintheservicestructure.Thefollowingpartofthepaperwillreviewthelawofitsdevelopmentandmakesananalysisofitscurrentcharacteristics,andtheexistingproblems .1　TheLawoftheDevelopmentoftheServiceStructure　　Fromthelate 1 980stotheendoflastcentury ,greatchan…