建筑业农民工就业培训之我见

农民工培训和继续教育是高速城市化发展进程中建筑业可持续发展的重要保证。本文对当前建筑业农民工培训存在的问题和困难进行了分析,对制约农民工培训工作长效机制建设的瓶颈进行了深层次的研究,提出了从构建体系、加强规划、政策引导、搭建平台、完善制度和营造氛围等六个方面优化农民工培训管理的一整套对策。对当前城市化进程中建筑业做大做强做优有一定的参考价值。     

Experimental studies on the effects of bearing supply gas pressure on the response of a permanent magnet disk-type motor rotor

Vibrations, particularly low-frequency vibrations caused by self-excited gas films, significantly affect the safety and economy of turbomachinery, which becomes dangerous at high rotational speeds. This experimental study focuses on the dynamic characteristics of a Permanent magnet (PM) disk-type motor rotor supported by gas aerostatic bearings. Nonlinear dynamic behavior, including double low frequency and gas film half whirling, was analyzed in the experiments. The dynamic features of double low frequency and gas whirling are described in the paper. The most important finding is that the sum of the whirling ratios of low frequencies 1 and 2 is always 1.00. The occurrence mechanism requires further study. The effects of bearing supply gas pressure on the dynamic response characteristics of the multi-disk PM rotor are implemented to improve rotor stability.     

金川二矿区围岩-充填体应力场的本构关系

本文结合金川二矿区充填机理研究工作的长期实践,应用粘弹塑性理论和增量计算方法,论述了围岩、矿体、充填体三者共同吻合变形作用的本构关系,较好地解决了金川二矿区一号矿体下向大面积胶结充填体和岩体共同作用时围岩的稳定性问题,计算结果与现场观测的围岩变形位移基本符合。为二矿区一号矿体采用大面积下向胶结充填、沿走向连续回采而不留间隔矿柱回采提供了理论依据。本项成果已在金川二矿区应用并取得了明显的效益。     

炸药乳化动力学唯象模型的建立及乳化器的设计

通过对乳化炸药乳胶基质形成过程中典型状态与动力学过程的划分与分析,提出了乳化动力学唯象模型。并阐述了能量输运中的高内相比、高粘度体系乳胶粒子的发展变化,建立了机械强制乳化的理想工作态。最后对合理设计高效的和接近理想工作态的准理想乳化器进行了探讨。     

基于局部路径重连的多星测控调度遗传交叉算子

为提高多星测控调度问题简单遗传算法的搜索精度,设计一种基于局部分层路径搜索的交叉算子(local layering path-relinking crossover operator,LLPRCO)。分析多星测控调度问题的遗传算法编码特点,得出解空间的复杂性和基因间较弱的相关性。借鉴路径重连的思想,利用构成初始解和引导解要素的差异性,构建从初始解出发的分层搜索邻域,将邻域中满足模型约束的解作为交叉的结果,并创建2个仿真场景进行验证。仿真结果表明,该交叉算子与具备一定随机特性的交叉算子混合使用能明显提高遗传算法对问题的求解性能。     

Homogeneous Strain Introduction Using Reciprocation Technique in High-Pressure Sliding

Metallurgical and Materials Transactions A - This study examines strain distribution occurring in the high-pressure sliding (HPS) processing for rods of pure Al and an AZ61 alloy. The strain...