Numerical Analysis of Plasma Initiated Polymerization

Plasma initiated polymerization is a kind of well-known radical polymerization mechanism, but it has the ＇living＇ polymerization feature and produces ultra-high molecular weight polymer. In order to explain such phenomena, we calculate the basic data of plasma initiated polymerization of methylmethacrylate （MMA） according to the principle of polymer physics and chemistry. It results in that the radical concentration ranges from 10^-12mol/L to 10^-16mol/L corresponding to the radical life in 10^4s to 10^8s, which means the radicals have a long lifetime. Moreover because of the long lifetime radicals it causes a unique feature rather than the common radical polymerization, and also shows no ＂living polymerization＂. It is noticed in experiments that there are two key factors playing important roles. One is the effective radical amount produced during the plasma discharging while the another is the diffusion factor.     

Influence of Iodine Vapour Pressure on Formation of XeI^＊ in Xe/I2 Mixture

The influence of the iodine vapour pressure on the mechanisms of XeI^＊ formation is investigated in Xe/I2 mixture by dielectric barrier discharge. The iodine vapour pressure is measured as a function of the ultraviolet （UV） intensity of XeI^＊ emission at 253 nm, and found that the UV intensity reaches a maximum at 0.9 Torr of iodine at a xenon pressure of 300 Torr, then decreases slowly with the iodine pressure larger than 0.9 Torr. The discharge mode transforms from a hybrid discharge at a xenon pressure of 760 Torr with 1.0 Torr of iodine to a diffuse mode at 10 Torr of iodine. These results are quite different from those of other rare-gas halogen excimers and indicate a different mechanism of XeI^＊ formation from those of other rare-gas halogen excimers.     

改变纳秒脉冲驱动波形提高等离子体显示平板维持期光效的研究

等离子体显示平板(PDP)作为自发光显示器件存在光效低、功耗大的问题。本文提出了一种新思路,利用快脉冲驱动改善PDP单元介质阻挡放电发光强度,提高电光转化效率。驱动源主要由低压信号经隔离放大后控制快速开关管开通、关断,实现正负几百伏双极纳秒脉冲输出。PDP工作在维持驱动期稳定放电状态下,测量了照度、相对红外辐射等特性参数。给出了上升沿和脉宽引起特性参数变化的曲线,以及硬开关阶段上升沿参数的选取的实验结果分析。研究表明,快上升沿脉冲有利于PDP单元放电过程紫外光充分激发并大大降低热效应,从而显著改善PDP的光效。     

新型大功率发光二极管路灯热管散热器设计与优化

针对大功率发光二极管(LED)路灯散热问题突出、外部热沉研究缺乏的情况,提出一种新型大功率LED路灯热管散热器设计。并针对热管散热器的充液率、倾角、单位功耗面积等关键设计参数进行分析或实验优化。实验表明,充液率在25%～30%、垂直方向倾角为60～80°,单位功耗面积在75～95cm2/W的一体式大功率LED路灯热管散热器具有优良的散热性能。     

Work Function Enhancement of Indium Tin Oxide via Oxygen Plasma Immersion Ion Implantation

Indium tin oxide (ITO) transparent conducting film was treated with oxygen plasma immersion ion implantation (PIII). X-ray photoelectron spectroscopy (XPS) was employed to characterize the effect. The results suggested that the oxygen content in the surface was increased and maintained for more than 50 h compared with traditional plasma-treated samples. Meanwhile, the work function of ITO estimated by comparing the peak shift in the XPS diagram suggested a corresponding increase by more than 1 eV.     

Enhanced Work Function of Al-Doped Zinc-Oxide Thin Films by Oxygen Inductively Coupled PlasmaTreatment简

Al-doped zinc-oxide （AZO） thin films treated by oxygen and chlorine inductively coupled plasma （ICP） were compared. Kelvin probe （KP） and X-ray photoelectron spectroscopy （XPS） were employed to characterize the effect of treatment. The results of KP measurement show that the surface work function of AZO thin films can increase up to 5.92 eV after oxygen ICP （O-ICP）＇s treatment, which means that the work function was increased by at least 1.1 eV. However, after the treatment of chlorine ICP （CI-ICP）, the work function increased to 5.44 eV, and the increment was 0.6 eV. And 10 days later, the work function increment was still 0.4 eV after O-ICP＇s treatment, while the work function after Cl-ICP＇s treatment came back to the original value only after 48 hours. The XPS results suggested that the O-ICP treatment was more effective than CI-ICP for enhancing the work function of AZO films, which is well consistent with KP results.     

Effect of Atmospheric Pressure Plasma and Subsequent Enzymatic Treatment on Flax Fabrics

The objective is to investigate the effect of atmospheric pressure dielectric barrier discharge (APDBD) plasma and subsequent cellulase enzyme treatment on the properties of flax fabrics. The changes of surface morphology and structure, physico-mechanical properties, hy?drophilicity, bending properties, whiteness, and dyeing properties of the treated substrate were investigated. The results indicated that atmospheric pressure dielectric barrier discharge plasma pre-treatment and subsequent cellulase enzyme treatment could diminish the hairiness of flax fab?rics, endowing the flax fabrics with good bending properties, water uptake and fiber accessibility while keeping their good mechanical properties compared with those treated with cellulase enzyme alone.     

Experimental Investigation of Surface Wave Plasma Excited by a Cylindrical Dielectric Rod

An improved surface wave plasma source equipped with a cylindrical quartz rod has been developed, which has great potential in processing inner wall of cylindrical workpieces. A cylindrical quartz rod not only excites the plasma around the rod, but also guides surface wave plasma along the rod. The distributions of plasma density and plasma temperature under different incident microwave powers and pressures are diagnosed by a Langmuir probe. The electron density near the rod is around the order of 10^11cm^-3. When the incident power is 450 W, the length of surface wave plasma column can reach up to 420 mm at 20 Pa.     

Enhanced Work Function of Al-Doped Zinc-Oxide Thin Films by Oxygen Inductively Coupled Plasma Treatment

Al-doped zinc-oxide(AZO) thin films treated by oxygen and chlorine inductively coupled plasma(ICP) were compared. Kelvin probe(KP) and X-ray photoelectron spectroscopy(XPS) were employed to characterize the e?ect of treatment. The results of KP measurement show that the surface work function of AZO thin films can increase up to 5.92 eV after oxygen ICP(O-ICP)'s treatment, which means that the work function was increased by at least 1.1 eV. However, after the treatment of chlorine ICP(Cl-ICP), the work function increased to 5.44 eV, and the increment was 0.6 eV. And 10 days later, the work function increment was still 0.4 eV after O-ICP's treatment, while the work function after Cl-ICP's treatment came back to the original value only after 48 hours. The XPS results suggested that the O-ICP treatment was more e?ective than Cl-ICP for enhancing the work function of AZO films, which is well consistent with KP results.