Quantitative Analysis of Structural Changes in Steel Caused by High-Temperature Holding in Hydrogen

We give a quantitative estimate of changes in the structure of 15Kh2MFA steel after its long-term exposure to the combined action of high temperature, tensile stresses, and hydrogen as the factors of degradation of this steel under conditions of oil hydrocracking. Under laboratory conditions, we study the effect of high-temperature hydrogen degradation of 15Kh2MFA heat-resistant steel on changes in the quantitative characteristics of its structural elements, in particular, in the dimension and average distance between carbides as well as in their orientation from one grain to another. Algorithms for the solution of the formulated problems are described, and the possibilities of proposed approaches for the quantitative automatic processing of metallographic images are shown.     

无线数据通信网发展趋势

无线数据通信具有两大发展趋势，即低速的广域移动数据网及高速的局域无线数据网。本文介绍了其技术特点、应用情况和市场前景，分析了无线数据通信传输技术、网络结构和媒质接入控制等问题。     

MICROSTRUCTURE STUDY OF CONSTITUENT PHASES IN 2024 SERIES Al ALLOYS

X-ray microanalysis,convergent beam electron diffraction(CBD)and selected area electrondiffraction(SAD)studies on the structures and compositions of the constituent phases in2024 series Al alloys have been conducted.Partial substitution of alloying elements is found tooccur in all the constituent phases,which cause small deviations from the stoichiometric com-positions reported in these ternary compounds.The dominant phase is α-Al_(12)(FeMn)_3Si whichhas a body center cubic crystal structure with the Im■ space group and a=1.25 nm.The nextdominant phase is Cu_2FeAl_7 which has a primitive tetragonal crystal structure with theP4/mnc space group and a=0.6336 nm,c=1.487 nm.The minor phase is α'-Al_(12)Fe_3Si hav-ing α primitive cubic crystal structure with the Pm■ space group and α=1.27 nm.     

TIG焊熔池外激谐振与熔透的关系

薄板TIG 焊时,利用脉动电流引起熔池振荡,当脉动电流与一定尺寸熔池自然振荡频率相同时,则熔池产生谐振,造成电弧长度及电弧电压有较大的往复变化。对电弧电压变动部分进行滤波,放大并用计算机采样,发现当熔池谐振时,电弧电压变动部分达到最大幅值,谐振后幅值很快衰减。本文以熔池谐振信号做为熔透信息进行熔透控制,给出了脉动电流电源,计算机检测系统。研究了熔透信号的变化规律及影响因素,在定点电弧及对接焊时,熔池尺寸与熔池谐振频率有较好的对应关系;以焊接电弧做为传感器,用熔池谐振频率控制熔透及熔池尺寸,有很好的重复性及较高的精度,这对解决熔透闭环自适应控制有很大的实际意义。     

新学期做点新东西，自制个性日历

1 选好壁纸 ①打开“壁纸之家”网站,地址：http：／／www．i816．net。 ②单击选择壁纸系列。 ③单击选择壁纸。     

Effect of the laser fusion of electrometallized coatings of the Fe-Cr-B-Al system on their corrosion resistance

We studied the effect of laser treatment of electric arc coatings produced of powder wires of the Fe-Cr-B system on the changes in their structure, electrolytic potential, and polarization currents. We additionally introduced aluminum, nickel, and copper to the charge of these coatings. Laser treatment was realized by means of Nd: YAG laser radiation. We have shown that the addition of a small amount of these elements to the coating under study in different ways affects the character of formation, structure, and electrochemical characteristics of the fused layer. In particular, copper and nickel additions increase the fluidity of the coating. The parameters of laser treatment affect strongly the uniformity of the distribution of elements in the fused zone. In the case of alloying with copper, the nonuniformity of their distribution is more pronounced, which can exert a slight negative influence on the corrosion characteristics of the coating. Aluminum addition improves the corrosion resistance of laser-modified coatings. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 42, No. 6, pp. 106–110, November–December, 2006.     

MR智能阻尼器试验研究及径向基网络模型

制作了MR智能阻尼器，并在不同的位移，速度和电流输入情况下，对自制的MR智能阻尼器进行了性能试验研究，建立了MR智能阻尼器的径向基函数网络模型。结果表明：神经网络模型能精确的描述阻尼器正向和逆向工作特性，并且对液体沉降、液体磁响应时间、蓄能器刚度等因素的影响也能很好的解决。     

基于注册表的网络攻击分析及相应解决方案

介绍了Windows注册表的结构以及修改注册表的操作方法，分析了在使用Windows操作系统上网时注册表可能受到的攻击，并提出了相应的解决方案和预防措施，来增强系统的安全性。     

高校“产学研”资源配置的结构优化模型

采用层次分析法建立了高校资源配置的结构优化模型，并进行了模拟运算。