旋转滑动弧氩等离子体裂解甲烷制氢

采用切向气流和磁场协同驱动的旋转滑动弧氩等离子体,先通过光谱分析法计算了其电子温度和电子密度,了解其物理特性,将其应用于甲烷裂解制氢,研究了进气流量和CH_4/Ar比对反应效果的影响。结果表明,该滑动弧系统电子温度为1.0-2.0 e V,电子密度高达1015cm~(-3),是介于热与低温等离子体之间的一种等离子体形式,具有独特的物理特性,可以在达到较高反应效率的同时,保持较大的处理量;在CH_4裂解制氢实验中,CH_4转化率可达22.1%-70.2%,并随进气流量和CH_4/Ar比的增大均逐渐降低;H_2选择性为21.2%-61.2%,并随进气流量的增大先基本不变后有所增大,随CH_4/Ar比的增大逐渐降低;与应用于甲烷裂解的不同形式的低温等离子体对比(如微波、射频、介质阻挡放电等)可以发现,旋转滑动弧在获得较高甲烷转化率、较高H_2选择性和较低制氢能耗的同时,还可以保持较大的处理量,即进气流量可达6-20 L/min。     

管内插新型自旋转子的流阻及抑垢特性

提出了一种新型自旋转子,并通过数值及实验方法研究了其流动阻力及抑垢特性.实验结果表明,在流速为0.76 m/s时转子转速仍可达100r/min,内插该转子的流动阻力比光管增加2倍左右,正反旋向转子组(每组4个转子)相问布置可防止沿流向转子转速递减,使转子转速基本恒定.数值分析表明,通过减小转子的旋转轴套外径并加前端导流...     

航空发动机旋转叶片振动监测系统研究

介绍了叶尖定时测量旋转叶片的原理，设计的光纤柬式传感结合光电接收实现了高精度的弱光检测。基于“5＋2”传感器均布方案，利用双速率对叶片振动信号进行采样，通过“5＋2”处理算法实现了振动频率的准确辨识，并在某航空设备上进行了高速模拟转子实验，实验表明测得频率与应变仪结果一致。     

Closely packed dense frequency selective surface

In order to realize wideband filtering properties of frequency selective surface （FSS）, FSS of closely packed elements is presented. The Y loop elements are chosen as the graphics elements. Based on the spectral domain method, the frequency response is analyzed for different incident angles and polarizations. The result of the numerical analysis shows that the dense FSS has wide passband with better independence of angle and polarization.     

高速扫描相机时间测量不确定度分析

以国内普遍使用的SJZ-30型高速扫描相机为例,用精测转速方法的结果处理数据,转速测量相对合成不确定度小于0.1%,时间间隔测量的相对扩展不确定度为0.2%.扫描速度在像面上的位置误差,采用"中值扫描速度",可予以校正.同时讨论了进一步降低转速测量不确定度和位置误差的方法.     

Fluidization of Nano-size Particles

Fluidization and collapsing bed experiments were performed with 'Tullanox', 10nm diameter fumed silica. The minimum fluidization velocity was determined to be 0.0115m/s at the unusually low volume fraction of solids of 0.0077. The solids volume fraction was measured using a -ray densitometer. Fluidization was without large bubbles, with a high bed expansion ratio. The highest granular temperature was of the order of that of Geldart B particles, as measured by Cody et al. (1996). The sedimentation process was simulated using a two-fluid hydrodynamic model. The input into the model was a measured solids stress modulus and an agglomerate size determined from the settling curves. With these two rheological parameters, there was good agreement between the sedimentation theory and the experiment. This study shows that the standard collapse bed experiment used in industry is a good test of rheological properties of particles.     

孔径旋转频闪散斑照相法测量物体的固有频率

提出了一种测量物体固有频率的新方法－－孔径旋转频闪散斑照相法。该方法能方便地测量振动物体的固有频率，具有精度高、全场显示、条纹可见度好等优点，给出了理论分析和实验结果。     

Some Logical Implications of the Two Einstein Assumptions Used in His Analysis of Geometry on a Relativistically Rotating Disc

We show that with the help of the two well known Einstein assumptions used by him in the treatment of geometry on relativistically rotating disc, and elementary logical analysis only, two different and opposite models of rotating discs can be constructed: In one of them the disc, set rotating from the stationary state, changes neither its radius nor circumference, as measured from stationary inertial frame; while in the other both the radius and the circumference contract by the same Lorentz factor. We also show that one can construct discs whose contraction factors vary continuously from unity (no contraction) to the full Lorentz factor.