排序方式: 共有12条查询结果,搜索用时 15 毫秒
1.
2.
庄娟 《冶金设备管理与维修》2001,19(5):36-36,38
介绍了台车下挠在线微机监测系统的配置及软件设计,以及实现在线监测所涉及的台车下挠信号的测量与处理技术。 相似文献
3.
在金属表面激光熔覆陶瓷材料过程中,过大的温度梯度产生的热应力易使熔覆层开裂。降低激光熔覆陶瓷材料过程中的温度梯度,一定程度上能够降低热应力,抑制裂纹缺陷产生。通过模拟计算Ti6Al4V基板上双激光束熔覆Al2O3涂层过程温度场的分布规律,提出采用能量均匀的平顶辅助激光束为熔覆过程提供预热缓冷的方法,通过改变平顶辅助光束光斑大小及功率密度,研究平顶辅助光束预热缓冷对熔覆层温度分布及温度梯度大小的影响。计算结果表明,平顶辅助激光束使熔覆过程出现明显的预热缓冷特征,能够有效降低熔覆层温度梯度。熔覆过程中Al2O3陶瓷塑性点(1533K)温度梯度随预热缓冷温度的升高而降低,但在预热缓冷温度升至塑性点附近温度时会引起塑性点温度梯度回升。实际加工中预热缓冷温度越高对加工过程越有利,但应避开塑性点附近温度。 相似文献
4.
As a spatially extended dissipated system, atmospheric-pressure dielectric barrier discharges (DBDs) could in principle possess complex nonlinear behaviors. In order to improve the stability and uniformity of atmospheric-pressure dielectric barrier discharges, studies on tem- poral behaviors and radial structure of discharges with strong nonlinear behaviors under different controlling parameters are much desirable. In this paper, a two-dimensional fluid model is devel- oped to simulate the radial discharge structure of period-doubling bifurcation, chaos, and inverse period-doubling bifurcation in an atmospheric-pressure DBD. The results show that the period-2n (n = 1, 2... ) and chaotic discharges exhibit nonuniform discharge structure. In period-2n or chaos, not only the shape of current pulses doesn't remains exactly the same from one cycle to an- other, but also the radial structures, such as discharge spatial evolution process and the strongest breakdown region, are different in each neighboring discharge event. Current-voltage characteris- tics of the discharge system are studied for further understanding of the radial structure. 相似文献
5.
To improve the microcrystalline silicon thin film deposition in quality and to increase its microcrystalline silicon content,we numerically investigated the characteristics of homogeneous discharges in hydrogen diluted silane and argon mixed gases at atmospheric pressure using a two-dimensional fluid model.The model takes into account the primary processes of excitation and ionization,sixteen reactions of radicals with radicals in silane/hydrogen/argon discharges,so this model can adequately describe the discharge plasma.The effects of very high frequency(VHF)excitation on the electron density in such discharges are analyzed.The simulation results show that the electron density does not linearly vary with the excitation frequency within from 90150 MHz.he maximum value occurs at an appropriate excitation frequency i.e.the transition frequency.Increasof the excitation frequency would effectively increase the electron density before the transition frequency,but decreases the density afterwards.is.Moreover,the densities of involved particle species,including H2+,H,Ar*,Ar+,SiH3+,SiH3,SiH3,SiH2are closely interrelated. 相似文献
6.
7.
基于透明电介质的烧蚀率计算模型,建立了飞秒激光烧蚀石英玻璃的微槽截面形状仿真模型,并通过烧蚀实验验证了模型的可靠性。利用所建模型分析了光斑半径、脉冲能量和扫描速度等参数对微槽截面形状的影响规律。研究表明,减小光斑半径、提高脉冲能量或降低扫描速度均可以提高微槽的槽深和侧壁角;微槽的槽宽随脉冲能量的提高或扫描速度的降低而增大,但随光斑半径的增大,其呈现先增大后减小的规律,在脉冲能量为4 J、扫描速度为0.2 mm/s的条件下,槽宽在光斑半径为13 m时达到最大值8.13 m。 相似文献
8.
介绍了NZM—01/02 型智能化溶液密度分析仪在线测量硫酸浓度时的使用技巧及常见故障的排除。 相似文献
9.
The characteristics of homogeneous discharges in mixed gases of hydrogen diluted silane and argon at atmospheric pressure are investigated numerically based on a one-dimensional fluid model.This model takes into account the primary processes excitation and ionization,sixteen reactions of radicals with radicals in silane/hydrogen/argon discharges and therefore,can adequately represent the discharge plasma.We analyze the effects of very high frequency(VHF) on the densities of species(e,H,SiH3,SiH+3 and SiH2) in such discharges using the model.The simulation results show that the densities of SiH3,SiH+3,H,and SiH2 increase with VHF when the VHF ranges from 30 MHz to 150 MHz.It is found that the deposition rate of μc-Si:H film depends on the concentration of SiH3,SiH+3,SiH2,and H in the plasma.The effects of VHF on the deposition rate and the amount of crystallized fraction for μc-Si:H film growth is also discussed in this paper. 相似文献
10.