一种离散混沌模型的控制讨论

本文方法的基本出发点是混沌吸引子的几何结构和混沌动力学对初值具有高度的敏感性,通过适当的调整动力学的可控参数,可将不稳定的轨道稳定下来.得到相应的吸引子.     

2D FEM analysis for coupled thermo-hydro-mechanical-migratory processes in near field of hypothetical nuclear waste repository

In order to consider the influence of temperature and stress fields on the migration of radioactive nuclide with underground water movement, an elastoplastic model and a 2D FEM code for analysis of coupled thermo-hydro-mechanical (THM) processes in saturated and unsaturated porous media were extended and improved through introducing the percolation and migration equation, so that the code can be used for solving the temperature field, flow field, stress field and nuclide concentration field simultaneously. The states of temperatures, pore pressures and nuclide concentrations in the near field of a hypothetical nuclear waste repository were investigated. The influence of the half life of the radioactive nuclide on the temporal change of nuclide concentration was analyzed considering the thermo-hydro-mechanical-migratory coupling. The results show that, at the boundary of the vitrified waste, the concentration of radioactive nuclide with a half life of 10 a falls after a period of rising, with the maximum value of 0.182 mol/m3 and the minimum value of 0.181 mol/m3 at the end of computation. For a half life of 1 000 a, the concentration of radioactive nuclide always increases with the increase of the time during the computation period; and the maximum value is 1.686 mol/m3 at the end of the computation. Therefore, under the condition of THM coupling, the concentration of radioactive nuclide with a shorter half life will decrease more quickly with water flow; but for the radioactive nuclide with a longer half life, its concentration will keep at a higher level for a longer time in the migration process.     

辽宁省流通领域节能灯商品质量合格率低(之二)

(2009-12-01)为加强对节能灯商品质量的监督管理,2009年7月,辽宁省工商局委托沈阳产品质量监督检验院对沈阳、丹东、铁岭等市流通领域的节能灯商品质量进行了监督检测。共抽查29个批次,25个批次不合格,不合格     

苹果采摘机器人机械臂优化设计及仿真

为了提高苹果采摘机器人的收获空间和采摘效率,减小机械臂的操作空间和结构尺寸,以适应果树的非结构化环境,结合苹果果树的特点和生长环境,采用参数化分析方法,探讨了机器人基座高度、采摘距离与机械臂长度、转角和操作空间、工作空间之间的关系,优化了苹果采摘机械臂结构参数,在求解位移正逆解和雅克比矩阵基础上,通过ADAMS和MATLAB建立了集三维实体设计、动力学建模、PD控制于一体的交互式仿真系统.仿真结果表明,在满足果园采摘条件的前提下,该机械臂结构简单、紧凑,能收获目标区域内90.2%以上的果实,以最优结构尺寸获得了最佳收获空间.     

MA制备GdSiGeDy合金系室温磁制冷性能研究

机械合金化(MA)是一种材料固态非平衡加工新技术.本文主要探讨稀土元素Dy在机械合金化工艺条件下对磁制冷合金GdSiGe磁熵变的影响,发现用机械合金化制备的GdSiGeDy合金系室温磁制冷材料不仅有光滑的磁熵变曲线,而且研究表明,由于元素Dy的加入在磁熵变达到单质Gd的两倍情况下大量减少使用昂贵元素Ge的结果,具有明显经济效益.     

电磁污染控制用S带吸波粉煤灰板材的制备

报道了根据λ/4型电磁波吸收原理,通过理论设计和模拟分析,以电厂废渣粉煤灰为介电材料,通过电阻膜复合,成功制备出新型粉煤灰吸波板材.实验表明,电阻膜的电阻为356Ω/□(方块电阻),厚度1.5 cm的粉煤灰板试样在S带(2~4 GHz),-10 dB吸收带宽达到60%以上,在2.9 GHz,最大吸收为-25 dB,新材料可用于室内电磁环境的改善和污染控制,并为粉煤灰的利用提供了新的高附加值途径.     

英台地区储层内部毫米级泥膜对开发的影响

大庆油田西部英台地区白垩系三角洲前缘粉砂岩储层中发育大量毫米级泥质薄层--泥膜,厚度在3mm以内.泥膜主要发育在三角洲前缘席状砂环境中,河口坝次之,水下分流河道中最少.根据岩芯观察统计,英台地区席状砂储层中的泥膜最大发育频率可以达到48条/米,频繁发育的泥膜在开发时能够改变砂岩内部的油水运移路线,间接起到了降低砂岩孔渗特征的作用.通过对同一个油藏模型在发育和不发育泥膜两种情况下开发特征进行数值模拟的结果对比,定量确定了泥膜的存在对含水率、采出程度和开发周期的影响,并对英台地区的泥膜发育情况提出了针对性的开发应对措施.     

机械合金化法制备W-Cu合金粉末的研究

将W80Cu20（n（W）：n（Cu）=4：1）混合粉末在QM-BP式行星式高能球磨机中球磨进行机械合金化,研究了不同球磨时间对W-Cu混合粉末组织的影响.采用XRD和SEM对不同球磨时间的粉末进行分析,结果显示随着球磨时间的增加,混合粉末产生合金化效果不断增强,Cu固溶于W中,并且晶粒尺寸得到一定的细化.     

A recognition method of vibration parameter image based on improved immune negative selection algorithm for rotating machinery

To overcome the limitations of traditional monitoring methods, based on vibration parameter image of rotating machinery, this paper presents an abnormality online monitoring method suitable for rotating machinery using the negative selection mechanism of biology immune system. This method uses techniques of biology clone and learning mechanism to improve the negative selection algorithm to generate detectors possessing different monitoring radius, covers the abnormality space effectively, and avoids such problems as the low efficiency of generating detectors, etc. The result of an example applying the presented monitoring method shows that this method can solve the difficulty of obtaining fault samples preferably and extract the turbine state character effectively, it also can detect abnormality by causing various fault of the turbine and obtain the degree of abnormality accurately. The exact monitoring precision of abnormality indicates that this method is feasible and has better on-line quality, accuracy and robustness.     

Hydrogen sorption properties of nanocrystalline Mg2FeH6-based complex and catalytic effect of TiO2

The diversities of hydrogen sorption properties of Mg₂FeH₆-based complexes with and without TiO₂ were investigated. Mg₂FeH₆-based complexes with and without TiO₂ were synthesized respectively by reactive mechanical alloying, and hydrogen sorption properties of the complexes were examined by Sieverts-type apparatus. The results show that the sample without TiO₂ releases 4.43 % (mass fraction) hydrogen in 1.5 ks at 653 K under 0.1 MPa H₂ pressure and absorbs 90% of the total 4.43 % (mass fraction) hydrogen absorbed in 85 s at 623 K under 4.0 MPa H₂ pressure. But for the sample with TiO₂ addition under the same condition, it only needs 400 s to release all of the stored hydrogen and 60 s to absorb 90% of the total hydrogen absorbed. The activation energies for desorption process of the samples with and without TiO₂ are determined to be 71.2 and 80.3 kJ/(mol·K), respectively. The improvement in hydrogen sorption rate and and reduction in activation energy can be attributed to the addition of TiO₂.