怎样使用高频氩放电色谱仪

简述了国标规定的氩气产品质量要求、检测原理、使用中常见问题及解决方法.     

离心式分级机分级理论与分级效能研究

介绍了离心式分级机的工作原理，分析了离心式分级机的流场特性，重点研究了速度特性和压力特性的分布规律，对离心机的分级效能以及改进方案进行了探讨，论述了细粉出口附加二次引风以及二相流入口速度对提高分级效率的的影响。     

温度变化对振动信号传输的影响分析

针对高温振动测试过程中出现的信号传输不稳定问题,建立了热电耦合模型,研究了高温环境对信号稳定传输所产生的影响.在相关热电磁理论的基础上,采用有限元方法建立了分析模型,电信号传输过程中产生的焦耳热与对流换热的共同作用,造成了传输线的温升.依据电信号-温度灵敏度变化关系,得出了外部环境的对流换热系数变化影响电信号传输的规律,建立了相应的误差公式估算输入与输出电信号响应之间的关系.研究结果表明:输入信号有效值越大,导体温升越大,输出与输入电信号间的偏离误差越大.并进一步确定了电信号稳定性传输的影响因素,为提高高温环境下结构测试的准确性提供了有效方法.     

旋成体大迎角分离流的Euler方程数值模拟

用三维Euler方程计算旋成体的大迎角绕流,我们发现:亚声速自由流时,计算得到的是无分离流动,与实际的分离流不相符合,因而计算的法向力大大小于有分离的实验值;而当自由流为超声速,且横向自由流M数较高时,由于背风表面出现激波,无粘Euler方程的数值计算能自动捕捉到背风面上的分离涡,计算法向力与实验值接近。为了对亚声速自由流用Euler方程数值模拟大迎角旋成体背风面上分离涡,根据问题的物理图像,在假设的分离线上,提出强加Kutta条件的方法,成功地计算出有分离流动,使计算的法向力与实验值接近。     

Simultaneous investigation of magnetospheric plasma and spacecraft charging

The results of magnetospheric plasma fluxes measurement in geosynchronous orbit are presented. The measurements were done onboard the geosynchronous Russian “Electro” spacecraft (SC) in 1995–1997 years. The diurnal variations of the plasma density and temperature were observed at various levels of geomagnetic activity.     

大功率电动机软起动技术及其应用

本文介绍了几种适用于大功率电动机起动的软起动装置的工作原理,对其技术、经济性进行了比较,探讨了软起动装置在大型设施中应用的可行性.     

直升机发动机燃油泵自吸油地面模拟试验中用正、负压模拟燃油过载的研究

本文推导了在势函数π=fz的有势力场中一维绝热定常流的能量方程,并对该方程进行分析,提出了在直升机燃油系统地面模拟试验中用正、负压模拟从油箱到发动机吸油口管路中燃油的过载来进行在各种飞行高度、各种供油状态下的发动机燃油泵自吸油地面模拟试验。     

低速风洞设计中的导流片损失问题

低速回流式风洞中拐角部位的流动损失占总损失的比重很大，该位置导流片绕流的流动状况对于流动损失有明显的影响。与常规的工程估算方法不同，风洞实验与数值计算相结合，并通过正交优化能够对不同工作条件下导流片流动及其性能指标的变化规律进行研究，对特定的导流片找到了最佳的工作条件。     

DF-9型及其改型高速机车和双层客车气动性能试验

DF-9型机车及其改型的气动性能试验研究结果表明，机车前部形状是直接影响机车气动阻力大小的重要因素，同时，也影响双层客车的阻力系数。采用裙板等减阻措施，能够取得较好的减阻效果。     

The Effects of Transverse Magnetic Field and Density Variations on the Particle Energy Spectra in a Reconnecting 3D Current Sheet

Electron and proton acceleration by a super-Dreicer electric field is further investigated in a non-neutral reconnecting current sheet (RCS) with a variable plasma density. The tangential B _z and transverse magnetic field components B _x are assumed to vary with the distances x and z from the X nullpoint linearly and exponentially, respectively; the longitudinal component (a ‘guiding field’) is accepted constant. Particles are found to gain a bulk of their energy in a thin region close to the X nullpoint where the RCS density increases with z exponentially with the index λ and the tangential magnetic field B _x also increases with z exponentially with the index α. For the RCS with a constant density (λ = 0), the variations of the tangential magnetic field lead to particle power-law energy spectra with the spectral indices γ₁ being dependent on the exponent α as: for protons and for electrons in a strong guiding field (β > 10⁻²) and for electrons in a moderate or weak guiding field (β > 10⁻⁴). For the RCS with an exponential density increase in the vicinity of the X nullpoint (λ≥ 0) there is a further increase of the resulting spectral indices γ that depends on the density exponent index λ as for protons and for electrons in weaker guiding fields and as for electrons in stronger guiding fields. These dependencies can explain a wide variety (1.5–10) of particle spectral indices observed in solar flares by the variations of a magnetic field topology and physical conditions in a reconnecting region. This can be used as a diagnostic tool for the investigation of the RCS dynamics from the accelerated particle spectra found from hard X-ray and microwave emission.