改进格鲁内基法

针对布切伯格等算法中存在的不足之处，采用取最高项进行约简，对多项式组彻底约简和根据秩的大小选取基组等措施对这些算法进行改进，从而形成本文的改进格鲁布纳基法。与现有算法相比，本文提出的方法以较少的计算工作量得到与原多项式组（PS）等价的格鲁布纳基（GS）或便于求解的三角型组（TS）。     

《筑路机械与施工机械化》编委会

<正>~~     

基于铁谱技术的磨损故障组合智能诊断模型的研究

机械设备的磨损对设备故障和使用维护非常重要。基于铁谱技术提出了磨粒识别的灰色关联度模型和BP神经网络模型组合优化识别的方法,试验和应用表明组合模型优于2种单一模型,较大地提高了预测精度。     

Dynamic Analysis of Micro-machined Diamagnetic Stable Permanent Magnet Levitation System

A novel micro-machined diamagnetic stable levitation system (MDSLS) which is composed of a free permanent magnetic rotor, a ring lifting permanent magnet and two diamagnetic stabilizers was presented. The static and dynamic stable characters of MDSLS were analyzed. The coupled non-linear differential equations were used to describe six-degree-of-freedom motion of the levitated rotor, and the equivalent surface current and combined diamagnetic image current method were utilized to model the interaction forces and torques between the lifting permanent magnet and rotor permanent magnet and also between the rotor permanent magnet and diamagnetic substrates. Because of difficulty to get analytical solution, the numerical calculation based on Runge-Kutta method was used to solve the dynamic model. The vibration frequencies were identified by fast Fourier transform (FFT) analysis. According to their resonance characteristics and parameters, the translational and angular dynamic stiffness were also calculated. The results show that the levitation of the rotor in MDSLS is stable, and the MDSLS is potential for the application in levitation inertial sensor.     

Friction characteristics in green drilling titanium alloy Ti6Al4V

Titanium alloy Ti6Al4V, as difficult-to-cut material, has poor machinability. Conventional cutting fluid serves as a coolant and lubricant. In green drilling, water vapor is recognized as an effective coolant; however, its lubrication properties are not well known in drilling. This paper investigates the friction characteristics between chip and tool in green drilling Ti6Al4V, compared with that in sliding and turning process. A friction evaluation model is developed based on the equivalent model of drilling, then is used to calculate the effective friction coefficient. Results indicate that the friction coefficient on the tool-chip interface is considerably reduced in drilling by water vapor, so the drilling forces decrease, too. The friction coefficient decreases as velocity increases in drilling, which is different from the law of sliding tests; the friction coefficient increases when the distance to chisel edge increases.     

《筑路机械与施工机械化》编委会

<正>~~     

2010年苏州金龙将实施两个新能源汽车项目

金龙联合汽车工业(苏州)有限公司对外宣布,自2010年1月份起,该公司将实施两个新能源汽车项目建设:一是投资1 500万元,与清华大学机械学院合作,成立清华-海格新能源客车研究所,专业研发各类新能源汽车;二是与苏州创元投资发展集团公司,以及苏州工业园区管委会合作,成立"海格新能源电驱动公司"作为生产基地,到2015年将在苏州形成年产3 000台各类新能源客车的产能,并通过整合目前苏州相关行业、企业资源,打造一条新能源汽车产业链.     

历史档案的价值再现

西安理工大学前身是北京机械学院和陕西工业大学于1972年合并组建的陕西机械学院。1994年1月经国家教育委员会批准更名为西安理工大学。北京机械学院的历史可追溯到20世纪30年代,由于     

利用吴方法求解3自由度并联机器人位置正解

首次利用吴方法求解一种典型的3自由度并联机器人的位置正解，将利用传统方法所得到的32次方程降为一个16次方程，提高了计算效率、在计算过程中，避免了增根的产生、得出对于这一类问题的普遍数学方法，为利用吴方法计算并联结构的正解提供了范例、     

提速货车转向架交叉支撑装置寿命的研究

通过动应力测试得到交叉支撑装置疲劳薄弱部位在线路运行中的应力谱，从而识别出提速货车交叉支撑装置在运用工况下的载荷，为其室内疲劳试验加载提供依据．根据疲劳薄弱部位在室内疲劳试验中的应力谱及该部位典型接头的S—N曲线，按照疲劳损伤等效原则建立交叉支撑装置的寿命预测模型，得到了交叉支撑装置实际运用寿命与室内疲劳试验加载循环次数的关系．