W型发动机双轴摆动故障的排除

简要介绍了DPF－2型控制系统在W型发动机上的应用，分析了该系统在使用过程中出现的双轴摆动现象，对整个系统的稳定性进行了探讨，采取措施解决了该发动机双轴摆动故障并进行了试验验证。该研究对进一步完善该型发动机的燃油控制系统有一定的参考作用。     

10°尖锥标模高超声速动导数的实验测量

在中科院力学所JP－4B高超声速脉冲风洞中，用模型自由飞方法对1°尖锥开展动态实验测量，并用参数微分法辨识得到了该模型的俯仰阻尼导数。文中还介绍了在模型优化设计，模型工艺以及实验测量记录和数据判读技术方面的一些进展。实验结果表明；脉冲风洞中模型自由飞方法得到的10°尖锥标模高超声速动态气动特性测量值与国外可比数据一致，重复测量精度与弹道把试验相当。     

应用流固耦合数值方法研究机翼的射流减振技术

采用流固耦合的数值计算方法研究了NACA 0 0 15翼型在大迎角 ( 15°～ 6 0°)范围的颤振 ,以及在翼型背部部分引入射流的减振技术。在流体区域用高精度、高分辨率算法求解Farve平均的Navier Stokes方程 ,在固体区域用四阶Runge Kutta法求解振动方程 ,并且每一个时间步后都在两个区域之间传递边界条件。计算结果表明在翼型背部引入适当射流会降低翼型的振动 ,并提高升力。但如果引入射流的速度过高 ,会在叶背处形成新的分离流 ,升力反而会下降     

钻孔法测量残余应力时释放系数的标定与计算

 <正> 用钻孔法测量残余应力时,使用的释放系数将对构件的残余应力测量精变产生影响。计算释放系数的理论方法有多种。其中普遍应用的公式,是由弹性力学通孔公式推导的应变片中心点处计算式。     

某型飞机同时存在两种惯性耦合问题的探讨

根据稳定性理论，对某型高速飞机的惯性耦合进行初步研究，首先，对飞机的滚转－偏航耦合－俯仰耦合的机理进行分析，然后，在不影响问题本质的前提下提出了一些假设条件，将研究惯性耦合的六自由度全量方程进行简化，求出急滚稳定性判据，以某型机为例，计算出其惯性耦合特性，用急滚稳定性判据进行了分析，并进行了验证 。     

生物组织光学参数：优化散射系数（μ’s）的实时在位测定

利用了一套特殊设计光纤探头组成的稳定态光纤光谱仪测试生物组织的光学参数，从悬乳液(Intralpid)与模拟胶(Phantom)实验推导出优化散射系数(Reduced scattering coeffcient：μ’s)近红外谱测量经验公式。测量反射系数就可以计算出优化散射系数谱。计算结果用模拟胶作了验证，并对大鼠脑组织μ’s进行了实时在位测量，从而得到了一种μ’s在位测量的有效方法。     

A coupling VWM/CFD/CSD method for rotor airload prediction

A coupling fluid-structure method with a combination of viscous wake model(VWM),computational fluid dynamics(CFD) and comprehensive structural dynamics(CSD) modules is developed in this paper for rotor unsteady airload prediction. The hybrid VWM/CFD solver is employed to model the nonlinear aerodynamic phenomena and complicated rotor wake dynamics;the moderate deflection beam theory is implemented to predict the blade structural deformation; the loose coupling strategy based on the ‘delt method' is used to couple the fluid and structure solvers.Several cases of Helishape 7A rotor are performed first to investigate the effect of elastic deformation on airloads. Then, two challenging forward flight conditions of UH-60 A helicopter rotor are investigated, and the simulated results of wake geometry, chordwise pressure distribution and sectional normal force show excellent agreement with available test data; a comparison with traditional CFD/CSD method is also presented to illustrate the efficiency of the developed method.     

Grinding temperature and energy ratio coefficient in MQL grinding of high-temperature nickel-base alloy by using different vegetable oils as base oil

Vegetable oil can be used as a base oil in minimal quantity of lubrication(MQL). This study compared the performances of MQL grinding by using castor oil, soybean oil, rapeseed oil, corn oil, sunflower oil, peanut oil, and palm oil as base oils. A K-P36 numerical-control precision surface grinder was used to perform plain grinding on a workpiece material with a high-temperature nickel base alloy. A YDM–III 99 three-dimensional dynamometer was used to measure grinding force,and a clip-type thermocouple was used to determine grinding temperature. The grinding force, grinding temperature, and energy ratio coefficient of MQL grinding were compared among the seven vegetable oil types. Results revealed that(1) castor oil-based MQL grinding yields the lowest grinding force but exhibits the highest grinding temperature and energy ratio coefficient;(2) palm oil-based MQL grinding generates the second lowest grinding force but shows the lowest grinding temperature and energy ratio coefficient;(3) MQL grinding based on the five other vegetable oils produces similar grinding forces, grinding temperatures, and energy ratio coefficients, with values ranging between those of castor oil and palm oil;(4) viscosity significantly influences grinding force and grinding temperature to a greater extent than fatty acid varieties and contents in vegetable oils;(5) although more viscous vegetable oil exhibits greater lubrication and significantly lower grinding force than less viscous vegetable oil, high viscosity reduces the heat exchange capability of vegetable oil and thus yields a high grinding temperature;(6) saturated fatty acid is a more efficient lubricant than unsaturated fatty acid; and(7) a short carbon chain transfers heat more effectively than a long carbon chain. Palm oil is the optimum base oil of MQL grinding, and this base oil yields 26.98 N tangential grinding force,87.10 N normal grinding force, 119.6 °C grinding temperature, and 42.7% energy ratio coefficient.     

谐振电路中品质因数的计算方法

从品质因数的原始定义出发,分别计算出简单RLC串、并联电路的品质因数,得到两个结论,并将其推广,提出了两种简单的计算品质因数的方法,最后通过求解一个实际的LC并联谐振电路的品质因数得到验证。     

汉乐府《陌上桑》罗敷形象再解读

《陌上桑》是一篇被世人广为传诵的汉乐府佳作,作品塑造一个鲜活的充满生命活力的女子形象———罗敷,她美丽、健康、自信、阳光、勇敢、自尊,一改传统诗文中女性的哀怨、病弱、卑怯、凄苦之态,成为文学史中一个光彩照人的独特形象,具有特殊的意义。