基于输出反馈的电液作动器自适应指令滤波控制

针对电液作动器跟踪控制中存在的结构化和非结构化的不确定问题,本文提出了一种输出反馈自适应鲁棒指令滤波跟踪控制方法.该方法结合了改进的LuGre摩擦补偿技术和自适应鲁棒指令滤波控制技术.自适应法则用来处理结构化不确定性;控制器鲁棒设计用来解决非结构化不确定性.除了位置信号外,速度、压力和摩擦力值均来自观测器,来自观测器的模型误差通过鲁棒设计进行补偿.指令滤波控制技术用来解决经典反步控制中固有的“复杂性爆炸”问题.控制器可以保证系统渐进稳定.通过对比实验证明了该方法在跟踪性能上的有效性.     

埋地钢质管道牺牲阳极的阴极保护

通过对埋地钢质管道在土壤中的腐蚀情况分析,阐述了牺牲阳极以保护阴极的重要性,并详细介绍了牺牲阳极法保护阴极的计算及安装方法.     

Study of the Development Road Map of China’s Renewable Energy

Renewable energy （RE） has been attached high attention around the world due to its carbon-free and indigenous production in a sustainable way. China enjoys plenty of renewable energy resources, particularly the wind, solar, hydro- and biomass energy, which could be a sound basis for a large-scale exploitation. This report examines the current status of RE technology and industry, analyzes the challenges of promoting RE in China. In order to pave the way for a long-term development of RE, this paper outlines the basic principles and priorities for individual RE technology. In line with these, the paper puts forward the RE targets and further describes the RE road map by 2020, 2030 and extend to 2050, taking consideration of China＇ s RE resources, industrial basis and energy demand etc. At last, this paper provides some recommendations to ensure the achievements of the RE targets.     

Study of solid solution strengthening of alloying element with phase structure factors

Using the empirical electron theory of solids and molecules (EET), the phase structure factors, nA and nB, of the carbon-containing structural units with mass fraction of carbon (wC) below 0.8% and the mono-alloy structural units with wC at 0.2% in austenite and martensite are calculated. The solid solution strengthening brought by C-containing interstitial solid solution and alloy-substitutional solid solution in γ-Fe and α-Fe is discussed at electron structural level. The coefficient (s) of solid solution strengthening is advanced according to the bonding force between atoms. The study shows that when the criterion is applied to the carbonaceous or alloying element-containing solid solution the results of calculation will coincide with the experimental result very well.     

岩溶水矿床开采的矿柱稳定性分析

谷家台铁矿是岩溶水矿床,在使用矿体顶板帷幕注浆防水的情况下,矿山采用点柱上向水平分层充填采矿法开采。针对矿柱稳定性问题,通过FLAC3D有限差分数值模拟方法,定量地计算和分析矿体开采过程中采场充填后不同开采步骤下采场点柱和间柱的应力、位移和塑性区的分布状况,模拟出它们随每步开采应力和应变的动态变化过程。根据模拟显示的间柱对上部矿体的支撑作用明显好于点柱结果,建议矿山在综合评价经济效益的基础上,可考虑每个矿房之间保留间柱,实现矿山的安全高效开采。     

Similarity solutions to a laminar boundary layer problem in power law fluids

A suitable similarity transformation is introduced to reduce the laminar boundary layer equations of power law fluids to a class of singular nonlinear two-point boundary value problems. The kin friction and shear stress distributions for boundary layer flow over amoving flat plate are investigated by utilizing the shooting technique. Results indicate that for each fixed value of the power law exponent n or the velocity ratio parameter xi, the skin frictionand shear stress decrease with the increasing of n or ξ respectively.