离心制冷机组冷凝/蒸发系统的化学清洗

针对该厂离心制冷机组冷凝 /蒸发系统严重积垢危及设备安全运行这一现状 ,研究出了一种适宜的清洗方案并成功地应用于现场。为化学清洗技术如何有效地用于制冷行业特殊污垢的处理 ,提供了一个成功的范例     

一种求解命题公式骨干集的警示传播算法

警示传播WP算法是一类重要的信息传播算法,在命题公式的可满足性判定中非常有效。通过对WP算法的数学原理分析发现,当算法收敛时以高概率固定部分变元的赋值,可以对公式进行化简。基于这样的特征修改WP算法的迭代方程和变元赋值条件,设计了一种求解命题公式骨干集的信息传播算法。当变元数目超过400时,与经典骨干集求解算法对比,效率提高了40%,与目前常用算法对比也有10%的提高。结果表明,所提算法求解命题公式骨干集时非常有效。     

卡尔曼滤波算法在MEMS热式风速风向传感器中的应用

针对MEMS热式风速风向传感器在实际使用过程中因噪声问题导致输出不稳定的现象,本文首次采用了卡尔曼(Kalman)滤波算法对本征白噪声进行滤波处理,从而优化传感器的输出性能.本文分别通过理论分析和仿真模拟证明了Kalman滤波算法的可行性.实验结果表明,通过调节相关参数,Kalman滤波算法在滤波效果、响应速度及误差上均优于传统的加权滑动均值滤波算法.除此之外,在消耗较少资源的前提下,Kalman滤波算法可以有效减少本征白噪声的干扰,且调节空间较大,可以适应不同的应用需求.     

Nonsmooth spatial frictional contact dynamics of multibody systems

Multibody System Dynamics - Computational prediction of 3D crutch-assisted walking patterns is a challenging problem that could be applied to study different biomechanical aspects of crutch walking...     

基于小型无人飞行器的CAN总线余度技术研究

随着航空技术和微电子技术的发展,航空电子系统朝着综合化、智能化、模块化、标准化和系统化的方向发展,CAN总线由于其低成本、协议开放、实现简单、速率快、挂接节点多的特点得到了广泛应用,而这又对其可靠性提出了新的要求;由于飞行器上的众多设备均作为节点挂在CAN总线上,如果总线出现故障会对飞行器的安全带来灾难性的后果;作者在对CAN总线模型进行分析的基础上提出一种双余度CAN总线模型,并给出了实现方法,经过实践验证,该方法切实可行,并显著提高了系统可靠性.     

Research and Application of Dynamic Equation for Full Frontal Impact

Full frontal impact theory needs researching and exploring to satisfy the primary safety design of occupant restraint system,avoiding the increasingly "engineering"trend in order to develop and design safety vehicle. After occupant restraint system is simulated by using linear elastic stiffness k,the occupant-vehicle frontal rigid barrier impact model is established. Dynamic equation of dummy chest coupling vehicle is built for full frontal impact based on ordinary vehicle deceleration by Hooke law,and the equation is solved by comparing coefficient and satisfying boundary qualifications. While relative vehicle characteristic parameters are kept unchanging,the actual vehicle deceleration is fitted to the simplified equivalent square wave( ESW),tipped equivalent square wave( TESW) and equivalent dual trapezoids wave( EDTW). Phase angle  and amplitude A of dynamic equations based on ESW,TESW and EDTW are calculated and deduced. The results show that: the dynamic equation of dummy chest coupling vehicle can be well utilized to instruct the primary safety design of full frontal impact for objective vehicle to satisfy chest deceleration demands and the equation based on TESW is best for this design.     

Non-Fourier heat conduction in a thin gold film heated by an ultra-fast-laser

Based on the dual-phase-lagging(DPL)heat conduction model,the Cattaneo-Vernotte(CV)model and the improved CV model we investigate the one-dimensional heat conduction in gold films with nano-scale thickness exposed to an ultra-fast laser heating.The influence of system parameters on the temperature field is explored.We find that for all the non-Fourier heat conduction models considered in this work,a larger Knudsen number normally leads to a higher temperature.For the DPL model,the large ratio of the phase lag of temperature gradient to the phase lag of heat flux reduces the maximum temperature and shortens the time for the system to reach its steady state.The CV model and the improved CV model lead to the similar thermal wave behavior of the temperature field,but the thermal wave speeds for these two models are different,especially for large Knudsen numbers.When the phase lag of temperature gradient is smaller,the difference between the DPL model and the improved CV model is not significant,but for the large phase lag of temperature gradient the difference becomes quite significant,especially for the large Knudsen number.In addition,the effect of the surface accommodation coefficient,which is a parameter in the slip boundary condition,on the temperature field of the gold film heated by ultra-fast laser pulses is investigated based on the DPL model.     

Oxidation behavior and mechanism of aluminum oxynitride (AlON) at elevated temperatures

The oxidation behavior and mechanism of aluminum oxynitride (AlON) powder exposed to air at elevated temperatures between 800°C and 1300°C was investigated by X-ray diffractometry (XRD), scanning electron microscope (SEM), electron spin resonance (ESR), nuclear magnetic resonance (NMR), and simultaneous thermogravimetry, differential thermal analysis, and mass spectrometry techniques (TG-DTA-MS). The weight of AlON gradually increases to a maximum value at 1150°C and then decreases with further heating. Meanwhile, AlON powder undergoes chemical changes, as evidenced by lattice expansion, and turns eventually into alumina. ESR spectra reveal the occurrence of lone pair electrons in the oxidized products and the intensity of corresponding resonance signal increases before disappearing with the increase in temperature. Combined with the results of NMR and TG-DTA-MS, the measured data suggest that Al-N in [AlO₃N] tetrahedron and [AlO₅N] octahedron are gradually oxidized into Al-O-N group with lone pair electrons, which causes continuous weight gain and lattice expansion. Further oxidation at higher temperatures results in alumina and N₂.     

视觉检测系统中亮度不均匀背景的一种去除方法

刀具形状视觉检测系统中，照明不均匀对测量结果影响很大。针对这种情况，提出了基于二维二阶多项式拟合并去除不均匀背景的方法。遵循最小均方程差原理，给出了二维二阶拟合的矩阵表达式。在编制的程序中，拟合点以人机交互形式由鼠标点击选出，程序自动记录所选点的图象人材与亮度值信息，然后拟合出背景曲面，并以二值图象形式给出去除背景后的目标图象。对一幅光照模型未知的网络图象进行了背景去除，实验结果良好。     

时效对接触线用Cu-Ag-Cr合金性能的影响

分析了固溶温度、时效及时效前冷变形量对Cu - 0 1 %Ag - 0 1 %Cr接触线用合金性能的影响 ,结果表明 :经 870℃固溶、 40 %～ 5 0 %冷变形及 480℃× 1 5h时效处理后 ,合金可获得良好的综合性能。