Gasification of polyethylene using steam plasma generated by microwave discharge

Gasification of polyethylene (PE) pellet was studied using atmospheric argon-steam plasma generated by microwave discharge and the feasibility of the process was examined. The experimental results showed that additional steam to argon plasma promoted the weight decrease of PE and enhanced the production of H₂, CO, CO₂ and CH₄. The results confirmed that the treatment of plastics with the steam plasma was effective to obtain synthesis gas.     

Time Characterization of High Density Gas Jet from a Pulsed Supersonic Nozzle via Laser Produced Plasma

A high-density gas jet supersonic nozzle is reported in this paper. The jitter and actuation time of the nozzle is determined by the pin discharge and laser spark radiation respectively. The jitter time of the nozzle is within 10μs with the backing pressure as high as 25 bar. With a nanosecond laser pulse focused on the gas jet about 1 mm below the nozzle, the actuation time is calculated to be about 15 ms by detecting the laser produced spark radiation, which reveals the existence of the gas jet and the relative gas density evolving with time. Consequently the gas density is estimated to be well above 10^19 cm^-3, compared with theoretical simulations from the nozzle parameters.     

美国危险废物处理的领先尖端技术--等离子强化熔炉介绍

从工作原理、主体结构、工艺流程等方面，系统地介绍了当代处理危险废弃物的领先尖端技术——等离子强化熔炉，并结合实地考察，介绍了其工业化发展及其应用实例。     

一种基于bit位的运动补偿方法

本文讨论了等离子体显示屏所特有的在显示运动画面时出现的伪轮廓线现象，对产生的原因进行了分析并给出了软件模拟的结果。在此基础上，提出了一种基于bit位的运动补偿方法来改善运动图像的画面质量，同时根据人眼的视觉特征对补偿方法做了进一步的优化。最后对基于bit位的运动补偿方法进行了比较和验证，结果表明基于bit位的运动补偿方法可以基本消除运动画面的伪轮廓线现象。     

The Structure of Clusters and Jets of Pulsed Plasma Expanding into Vacuum

The space-time distribution of the basic kinetic parameters of a plasma is experimentally determined under conditions of expansion of plasma clusters and jets into vacuum. It is demonstrated that the dynamics and structure of plasmoids injected by pulsed erosion plasma accelerators of the electrothermal type are characterized by two successive stages or two modes of acceleration, namely, the Joule heating of electrons in the initial region of the path and the collisionless expansion of rarefied plasma.     

Plasma Sprayed Hydroxyapatite Coatings with Nano-hydroxyapatite Prepared by Ultrasonic Precipitation Process

Nano-particle hydroxyapatite （ HA ） was prepared with a novel ultrasonic precipitation process and the as-prepared nanopowder was used to produce hydroxyapatite （ HA ） coatings on titanium substrate via plasma spraying. The phase and the microstructare of the coating were characterized by X- ray diffraction （XRD） and scanning electron microscopy （SEM）. Results showed that spherical particles could be prepared by ultrasonic precipitation process; and a corresponding dense HA coating with molten surface and low-porosity cross-section structure was acquired. During the plasma spraying process, new phases of Ca3 （ PO4 ）2 and Ca2 P2O7 were generated. After heat-treating at 800℃ for 1 h, the contents of Ca3 （ PO4 ）2 and Ca2 P2O7 decreased while HA content increased. Tensile adhesion tests showed that the plasma sprayed coating prepared with the spherical nanoparticles exhibited high tensile bond strength.     

Inductively coupled plasma etching of InGaP, AllnP, and AlGaP in Cl2 and BCl3 chemistries

Dry etching of InGaP, AlInP, and AlGaP in inductively coupled plasmas (ICP) is reported as a function of plasma chemistry (BCl₃ or Cl₂, with additives of Ar, N₂, or H₂), source power, radio frequency chuck power, and pressure. Smooth anisotropic pattern transfer at peak etch rates of 1000–2000Å·min^?1 is obtained at low DC self-biases (?100V dc) and pressures (2 mTorr). The etch mechanism is characterized by a trade-off between supplying sufficient active chloride species to the surface to produce a strong chemical enhancement of the etch rate, and the efficient removal of the chlorinated etch products before a thick selvedge layer is formed. Cl₂ produces smooth surfaces over a wider range of conditions than does BCl₃.     

AHMED experiments on hygroscopic and inert aerosol behaviour in LWR containment conditions: experimental results

Hygroscopic NaOH, CsI, CsOH and inert Ag aerosol behaviour at different temperatures and relative humidities (RH) has been studied in a well instrumented and controlled vessel of 1.81 m³ total free volume. Homogeneous thermal-hydraulic conditions for aerosol measurement in the vessel were achieved. The aerosol number and mass concentration were measured continuously during the experiments using a Condensation Nucleus Counter and a Tapered Element Oscillating Microbalance. The particle size distribution and chemical composition in the test conditions were measured by Berner low pressure impactors. In the case of NaOH the half life of the aerosol mass concentration was more than four times longer at low RH (22%) as compared to high RH (96%). The half lives of the CsOH and CsI aerosols were only twice as long at low RH as compared to high RH. Thus at high RH (96–97%) the half lives of CsOH and CsI were twice as long as the half life for the NaOH aerosol. The faster decay of the NaOH aerosol is due to the smaller density decrease of NaOH during water condensation. CsOH particles grew rapidly to their equilibrium size at all humidities. The measured equilibrium size for CsOH aerosol agree well with the calculated particle size at different RHs. Experimental results were also compared with calculations obtained by severe accident computer codes. These calculated results will be presented in a later paper.     

高功率激光焊接光致等离子体的检测

系统地归纳了高功率激光焊接过程中光致等离子体的声、光、电、热等四种特征信号，综述了国外在等离子体信号检测方面的试验方法及研究进展，分析了未来的发展趋势     

Plasma Discharge Initiation of Explosives in Rock Blasting Application： A Case Study

A plasma discharge initiation system for the explosive volumetric combustion charge was designed, investigated and developed for practical application. Laboratory scale experiments were carried out before conducting the large scale field tests. The resultant explosions gave rise to less noise, insignificant seismic vibrations and good specific explosive consumption for rock blasting. Importantly, the technique was found to be safe and environmentally friendly.