盐的某些神秘功能

除了调节身体的水量之外,盐还有其他许多重要功能。盐是一种强效的天然抗组胺剂,它可以缓解和消除哮喘症。在喝完一杯或两杯水后,把盐放到舌头上,它就和呼吸器一样有效,而且不会产生毒性。盐的这种使用方式,只适用于因干渴而处于危机状态的身体。在通常情况下,你应该把盐放到食物或水中。     

磨煤机钢球装载量对机组制粉系统的影响分析

为了降低某电厂厂用电率并提高磨煤机的可靠性,结合其他电厂的经验,分析了磨煤机的运行情况,论述了磨煤机钢球最佳装载量对制粉系统的影响。通过调整钢球装载量,降低了机组电耗,提升了机组运行的经济性。     

Hot compressive deformation behavior and constitutive relationship of Al-Zn-Mg-Zr alloy with trace amounts of Sc

Abstract： The hot deformation behaviors of AI-Zn-Mg-Sc-Zr alloy were investigated in a temperature range of 340-500℃ and a strain rate range of 0.001-10 s 1 using uniaxial compression test on Gleeble-1500 thermal simulation machine. The results show that the flow stress increases with increasing strain and tends to be constant after a peak value. The flow stress increases with increasing strain rate and decreases with increasing deformation temperature. The phenomenon of dynamic recovery and dynamic recrystallization can be observed by microstructural evolutions. Based on the hyperbolic Arrhenius-type equation, the true stress-true strain data from the tests were employed to establish the constitutive equation considering the effect of the true strain on material constants （α, β, Q, n and A）, which reveals the dependence of the flow stress on strain, strain rate and deformation temperature. The predicted stress-strain curves are in good agreement with experimental results, which confirms that the developed constitutive equations are suitable to research the hot deformation behaviors of Al-Zn-Mg-Sc-Zr alloy.     

Fluid flow characteristics of single inclined circular jet impingement for ultra-fast cooling

The fluid flow characteristics of the single bunch inclined jet impingement were investigated with different jet flow velocities, nozzle diameters, jet angles and jet-to-target distances for ultra-fast cooling technology. The results show that the peak pressure varying significantly from nearly 0.5 to above 13.4 kPa locates at the stagnation point with different jet diameters, and the radius of impact pressure affected zone is small promoted from 46 to 81 mm in transverse direction, and 50 to 91 mm in longitude direction when the jet flow velocity changes from 5 to 20 m/s. However, the fluid flow velocity is relatively smaller near the stagnation point, and increases gradually along the radius outwards, then declines. There is an obvious anisotropic characteristic that the flow velocity component along the jet direction is about twice of the contrary one where the jet anlge is 60°, jet diameter is 5 mm, jet length is 8 mm and jet height is 50 mm.     

基于D-S证据理论的变电站设备状态监测模型

为了提高变电站设备的供电可靠性,根据已有的设备状态监测方法,利用小波分析方法和D-S证据理论,提出了一种变压器状态监测模型,通过对变电站设备特征量的分析来实现对变电站设备状态的实时监测.     

善良,也是一种人性的“高贵”

人,作为生命个体,非常敏感地感受、接受、承受着一切影响。于是,在我们生命中有过许多快乐!于是,我们也有诸多的愁苦和烦恼!人,有时需要质疑与被质疑;有时需要信任与被信任。其实,每个人都在一种漩涡中生活——无论你愿不愿意、承     

广义Delta算子系统的状态反馈容许控制

针对广义Delta算子系统,本文利用线性矩阵不等式方法研究状态反馈容许控制问题,给出广义Delta算子系统容许的一个新的充分必要条件,并为不容许的广义Delta算子系统设计了合适的状态反馈控制器,保证所得的闭环系统容许。数值算例表明,本文所得结果是有效和可行的。     

基于状态观测器的一类不确定性线性系统鲁棒保性能控制器设计

针对一类范数有界和具有外界干扰的状态不可测的线性系统,提出了一种根据观测器的鲁棒保性能控制器的设计方法.通过利用Lyapunov稳定性原理和H∞理论,可以得出鲁棒保性能控制器存在的一个充分条件.所设计的控制器不仅能保证闭环系统的稳定性,而且也能保证闭环系统具有一定的线性二次性能指标和H∞性能指标.利用仿真研究,得出所提方法的有效性.