Structure and internal-stress formation in VT20 titanium-alloy welded joints

Microstructure, texture, and microhardness and residual-stress distributions are studied in a VT20 alloy welded shell consisting of two coaxial nested components connected by a circular weld.     

A study of the phase composition of iron-ore briquets to assess their behavior in a blast furnace

We study a mechanism for maintaining the strength of cement-bonded iron-oxide-bearing briquets when heated under reducing conditions. These briquets retain their strength when heated in a reducing atmosphere: up to 700–750°C, strength retention is due to the cement stone; strength retention under further heating is due to the continuous metal shell formed on the surface of the briquet as the iron oxide in the surface layer of the briquet is reduced to iron. Fabrication and usage of briquets of iron-ore concentrate can be recommended as a wash material for blast furnaces. Disperse materials containing SiO₂ and MgO should be added to the charge during fabrication of the briquets in order to improve the washing properties of briquet slag.     

General solution of one-dimensional,time dependent coupled heat flow systems

A new, powerful method of analysis, involving the combined use of finite integral transform and finite element techniques, is presented for the solution of time dependent heat flow systems composed of many one-dimensional elements connected through the nodes. This method leads to an eigenvalue problem which is not of the conventional Sturm-Liouville type. A procedure for the determination of the eigenvalues is described. The solution obtained is in the form of an infinite series and contains quasi-steady and transient terms. The general solution obtained can be applied in the mathematical modelling of many engineering applications such as the determination of the penetration of the daily temperature cycle into buildings, the analysis of heat transfer in array of extended surfaces in compact heat exchangers, and many others.     

Robust Stability Conditions for a Family of Linear Discrete-Time Systems Subjected to Uncertainties

Automation and Remote Control - Robust stability conditions are established for a family of linear discrete-time systems subjected to uncertainties. The traditional approach, which involves the...     

Change in the structure of alloy VT22 with the combined action of ultrasonic radiation and thermal cycling treatment

A study is made of the structure of alloy VT22 with thermal cycling treatment (TCT) and also with TCT and prior ultrasonic irradiation (USI) by the methods of metallography, electron microscopy, and hardness measurements. It is shown that TCT for annealed specimens promotes recrystallization, fragmentation, and spheroidization of and phases.It is established that TCT of specimens quenched to phase previously treated with ultrasonic radiation leads to formation of -phase platelets of considerably smaller dimensions and more strongly fragmented compared with -phase platelets after TCT for unirradiated specimens.Translated from Problemy Prochnosti, No. 10, pp. 47–49, October, 1990.     

Method of monitoring the condition of a blast-furnace bottom

Krivorozhstal Combine. Translated from Metallurg, No. 1, p. 25, January, 1990.     

A study of Nd2Fe14B and a neodymium-rich phase in sintered NdFeB magnets

The microstructure and properties of NdFeB sintered permanent magnets were analysed by different methods. Samples analysed were sintered and thermally treated. The hard magnetic Nd₂Fe₁₄B phase and amorphous neodymium-rich phase were observed by TEM. The neodymium-rich phase contained iron and boron, in elemental and in B₂O₃ form, which is known as a glass former. At the sintering temperature, Nd₂Fe₁₄B and the neodymium-rich phase are supersaturated with iron, which should be dissolved at the annealing temperature to react with neodymium and boron and form additional Nd₂Fe₁₄B phase. Iron precipitates of size up to 2 nm were detected in the Nd₂Fe₁₄B phase. These superparamagnetic precipitates of -Fe could affect the hard magnetic properties of NdFeB magnets.     

一种基于软件无线电的中频数字接收机的设计实现

中频数字接收机是随着数字信号处理技术的不断发展而成熟起来的;此文主要是基于软件无线电的思想,采用MATLAB和DSP相结合的新颖开发方法,利用MATLAB-DSP集成开发环境Embedded Target for the TI TMS320C6000DSP Platform,从Simulink模型自动生成TIC6000DSP的可执行代码,从而缩短了DSP算法软件的研发周期;文中的输入信号是AM调制信号,采样率为1.6MHz,调制信号为2kHz,载波为400kHz,经过128倍抽取和滤波,最后输出数据流速率为12.5kHz;通过仿真实验证明,采用软件无线电的思想不仅满足了设计需求,而且增强了不同系统之间的互通性、兼容性、灵活性和可靠性,同时降低了成本。