变频器在电梯改造中的应用

介绍了电梯改造中用一台变频器实现电梯升降及门开关控制的方法 ,以及电梯调试的一点体会 .     

椎间盘镜治疗腰椎间盘突出症护理体会

目的探讨椎间盘镜治疗腰椎间盘突出症护理体会。方法对65例经椎间盘镜手术治疗腰椎间盘突出症患者术前、术后护理及健康教育。结果全部患者均顺利渡过围手术期,未发生并发症,临床症状缓解或消失。结论做好手术全过程的护理,对巩固手术疗效和促进患者康复至关重要。     

The Effect of Gas Flow Rate on Radio-Frequency Hollow Cathode Discharge Characteristics

It is known that gas flow rate is a key factor in controlling industrial plasma processing. In this paper, a 2D PIC/MCC model is developed for an rf hollow cathode discharge with an axial nitrogen gas flow. The effects of the gas flow rate on the plasma parameters are calculated and the results show that： with an increasing flow rate, the total ion（N＋2, N＋） density decreases, the mean sheath thickness becomes wider, the radial electric field in the sheath and the axial electric field show an increase, and the energies of both kinds of nitrogen ions increase;and, as the axial ion current density that is moving toward the ground electrode increases, the ion current density near the ground electrode increases. The simulation results will provide a useful reference for plasma jet technology involving rf hollow cathode discharges in N2.     

Characterization of Nitrogen Glow Discharge Plasma via Optical Emission Spectrum Simulation

Optical emission spectroscopy in nitrogen glow discharge plasma is simulated, and the collision excitations and characteristic emissions of the species （N2, N2^＋, N^＋, N） are investigated by a Monte Carlo model for nitrogen molecular gas discharge. The excitation rates of the main excited states are calculated and the corresponding relation and relative magnitude between the distribution of excitation rate of a certain excited state and the distributions of the emission rates of various lines originating from this excited level are also explored. The simulated results are compared with the experimental measurements in two typical discharge conditions. The luminescence mechanism of the line N2^＋： 391.4 nm is explained based on the microscopic plasma processes. The cathode glow in N2 discharge is found to be mainly caused by N^＋ impact excitation and the intensity of cathode glow decreases with the voltage. The corresponding relation between the emission rate or intensity of the 391.4 nm line and the production rate and the density of N2^＋ is also examined.     

Accurate quantitative CF-LIBS analysis of both major and minor elements in alloys via iterative correction of plasma temperature and spectral intensity

The chemical composition of alloys directly determines their mechanical behaviors and application fields.Accurate and rapid analysis of both major and minor elements in alloys plays a key role in metallurgy quality control and material classification processes.A quantitative calibration-free laser-induced breakdown spectroscopy (CF-LIBS) analysis method,which carries out combined correction of plasma temperature and spectral intensity by using a secondorder iterative algorithm and two boundary standard samples,is proposed to realize accurate composition measurements.Experimental results show that,compared to conventional CF-LIBS analysis,the relative errors for major elements Cu and Zn and minor element Pb in the copperlead alloys has been reduced from 12％,26％ and 32％ to 1.8％,2.7％ and 13.4％,respectively.The measurement accuracy for all elements has been improved substantially.     

Effect of gas flow on the nanoparticles transport in dusty acetylene plasmas

This article presents simulation results on the effects of neutral gas flow for nanoparticle transport in atmospheric-pressure, radio-frequency, capacitively-coupled, and acetylene discharge. The acetylene gas is set to flow into the chamber from the upper showerhead electrode. The internal energy of the gas medium therein is transferred into kinetic energy so the gas advection can be triggered. This is represented by the pressure volume work term of the gas energy converse equation. The gas adv...