Asymptotic solution of the optimal speed problem for the quasilinear system under Euclidean constraint on control

For the system with a small parameter under nonlinearities, consideration was given to the problem of optimal speed. The values of the multivariable control actions are bounded in the Euclidean norm. The theorem of existence and asymptotic properties of the solution of this problem was proved. It underlies the algorithm to construct asymptotic arbitrary-order approximations to the optimal control.     

基于Mega8单片机和AD9833的正弦波信号发生器

正弦波信号作为一种基准信号广泛应用于各种电路中，产生正弦波信号的方法有很多种，DDS（Direct Digital Frequency Synthesis直接数字频率舍成器）作为一种新型技术，具有相对带宽宽，频率转换时间短，频率分辨率高，控制灵活方便等优点，成为现代频率合成技术中的佼佼者。AD公司生产的AD9833是一款低功耗、可编程波形发生器，在Mega8单片机的控制下可生成0-12．5MHz的正弦波，还可以生成三角波和方波。经现场验证，基于Mega8单片机和AD9833的正弦波信号发生器，可以非常方便地生成各种频率的正弦波。     

国内外小井眼钻井设备的发展

由于小井眼钻井成本低、排出岩屑体积小，对环境污染小，近几年来在世界范围内得到了大力发展，因此，各种小井眼钻井设备应运而生。介绍了目前国外小井眼钻井设备的发展状况及特点，提出了我国发展小井眼钻井设备的建议，并给出了一种小井眼钻机的初步方案。     

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.     

《C语言程序设计》教学中问题和改进方法的探讨

《C语言程序设计》是计算机专业学习中的一门基础的课程．是培养学生对计算机学习兴趣的关键课程。提出C语言教学过程中存在的一些问题。对问题进行分析,提出解决问题的方法。根据笔者的多年的教学实践,阐述一些教学方法和教学经验,对教师在教学思路和方法上有一定的指导意义,能够更好地提高教学水平。