粒子

Such as: calibrating the laser system, calibrating the measurement region and focusing the CCD camera for the diffuser passage with complex shape, selecting the best incidence angle for the laser sheet,, setting the time parameter including the time between pulses and the time between records, designing the laser system, and selecting water fog with 1～5μm diameter as seedings for PIV measurement after comparing several particles. All of the work is useful to accumulate the PIV measurement experience in turbomachinery. 2. Experimental research of the unsteady flow in diffusers The instantaneous velocity fields within the vaneless and vaned diffuser were measured by using PIV technique.

本文在国内首次进行PIV测量系统对离心风机扩压器内部非定常流动的测量，为此，作者作了必要的实验前期工作：双谐振激光器工作特性的标定；针对扩压器复杂的流道形状，解决了片光源照射区域位置的标定和CCD相机的聚焦等问题；为复杂流道形状的扩压器内部流动的PIV测量选择了最佳片光源入射角度；选择了合适的PIV测量时间参数；为实现非定常内流的PIV测量设计了PIV系统的光路布置；根据非接触测量示踪粒子的选取原则，对几种示踪粒子进行了筛选，最终1～5μm的水雾粒子在本文实验条件下获得最佳效果。

The result shows that B combines with N prior to Al at high temperature and brings about coarse particles of BN (about 900 nm), which effectively reduces the amount of fine and dispersive AlN particles, and BN precipitate clinging to MnS precipitation coarsens MnS particles, the pinning of austenite grain boundary is alleviated and the grain growth of ferrite is suppressed.

结果表明高温时B优先于Al与N结合生成粗大的BN粒子(约900 nm)，有效降低了热轧过程细小而弥散的AlN析出量，同时BN依附MnS析出而粗化MnS粒子，减弱了细小弥散析出粒子对奥氏体晶界钉扎以及相变后铁素体晶粒长大的抑制作用。

After summarizing BSS algorithm of convolved mixture and its applications, the paper applies the improved PSO algorithm to convolved mixture BSS and proposes the PSO algorithm based on simulated annealing method. The paper also does some experiments of BSS based on PSO algorithm with grads acceleration and analyzes the simulation results.

4在总结卷积混合的盲源分离算法及其应用之后，将改进型粒子群算法应用到卷积混合的盲源分离中，给出了基于模拟退火思想的粒子群算法和基于带有梯度加速的粒子群算法的盲源分离的仿真实验，并对仿真结果作了分析。

In this paper, several coloring pigments were synthesized and the sheet metal powders were coated by these pigments with the technology of super powder preparing and particle compositing. The coated composite particles were prepared by these, and the metallic luster of the metal powders were defiladed. The mechanism and the processing conditions of composite particles were researched.

本论文以超细粉体制备及粒子复合技术为基础，在金属粉表面包覆一层红外透明性较好的着色颜料，遮盖金属粉的金属光泽，制备出包覆式复合粒子，对复合粒子的制备的机理及工艺条件进行了研究。

Meanwhile, we discuss the deinking mechanism: solvent treatment dislodges most ink particles from the fibers, then ultrasonic treatment scatters detached ink particles which are separated from the stock by following washing and floatition process, so that deinking efficiency is improved greatly.

同时 我们对其脱墨机理进行初步研究，可以这样认为：先用溶剂预处理，将大部分油墨粒子从纤维上分离下来，然后再辅以超声波的作用，将分离下来的油墨粒子打碎，在后面的浮选洗涤过程中将这些打碎成很细小的油墨粒子去除，从而大大地提高了混合办公废纸的脱墨效果。

However, the aggregation of nanoparticles occurred with increasing particle concentration due to the strong magnetic interaction between particles. This caused the disordering of composite.

然而，随著粒子浓度的增加，由於磁性粒子间的磁性作用力，粒子聚集的现象也渐趋严重，这也造成复合物变为不规则的形态。

Photoluminescence properties of ZnSe/silica gel-glasses were investigated by an advanced spectrum system. Excitated by laser of two different wavelength, the electron transition occurred in two different relaxation approaches. Interband radiation spectra and the surface defect radiation spectra of ZnSe nanoparticles were obtained. The correlation between the wavelength of eradiated light and the incident light verifies that the electronic-hole structures change with the size of the nanoparticle.

利用先进的稳态光谱测试系统研究了ZnSe/SiO〓凝胶玻璃纳米复合材料的光致发光特性，凝胶玻璃基纳米复合材料样品中观察到不同波长激发光激发样品，导致激发态电子经两种不同的弛豫途径的辐射跃迁发光，即ZnSe纳米粒子的带间发射光谱和ZnSe纳米粒子的表面缺陷态发光，辐射光的波长与入射光的波长是连续相关的，证实了凝胶玻璃中ZnSe纳米粒子存在随尺寸变化分立的能级结构。

Three approaches are investigated to prepare carbon-based Pt nano-catalyst. Size of Pt nanoparticles made from the macerating and microemulsion integraled method are comparatively small, about 7nm.

采用三种路线研制了碳基铂纳米催化剂，其中结合浸渍法与微乳液制备纳米粒子的方法，即活性炭附载微乳液体系中制备的Pt纳米粒子，制得的催化剂中的Pt纳米粒子较小，约7nm左右。

The proposed algorithm reserves both good fitness particles and the diversity of particles in evolution process,which improves the ability of PSO in getting rid of the local extreme value and meliorates its convergent speed and precision.

该算法在保留高适应度粒子的同时，确保了粒子的多样性，从而改善了粒子群优化算法摆脱局部极值点的能力，提高了算法的收敛速度和精度。

Therefore, the reactivity of Al nanopowders in air depends on the particle size, the preparation method, as well as the type, structure and thickness of the surface passivating layer.

因此，纳米铝粉的活性，不仅取决于粒子的尺寸大小，还取决于粒子的制备方法，以及粒子表面包覆壳层的种类、结构、厚度等。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。