Catalysis and plasma chemistry at solid surfaces

Heterogeneous and homogeneous non-equilibrium plasma chemistry offers a range of potential advantages compared to conventional thermal activation and synthesis methods. Some examples of how such low temperature electrical discharges can be effectively utilised for selective chemical reaction pathways are given. These include the fluorination of C-H bonds, the synthesis of polyozonides, selective ring opening polymerisation, and the conversion of alkali metal halides to nitrates using air.     

p-Si薄膜生长的ECR-CVD等离子体系统的结构设计

提出了一种生长p-Si薄膜的ECR-PECVD等离子体系统。系统采用永磁铁和线圈相结合，改善反应室磁场的均匀性；微波窗口设计成多层结构．避免窗口污染；衬底托架移动和旋转利于改善生长膜的均匀性。     

激光驱动离子加速的研究进展及其重要应用综述

随着激光技术的不断发展,特别是啁啾脉冲放大技术被提出以来,超强激光脉冲驱动的离子加速研究逐渐吸引了国内外科学家们的广泛关注,在离子能量提升、发散角控制和单能性提高等方面相继取得一系列重要进展。由激光与等离子体相互作用产生的离子束具有能量高、脉宽窄和方向性好等特点,具有许多潜在应用。本文通过回顾激光驱动离子加速的研究历程,对离子加速的主要作用机制、基本理论模型、数值模拟和实验研究等进行详细的阐述,同时对激光驱动离子加速的重要应用进行归纳总结。最后根据当前国内外大型激光装置的发展趋势,对极端光场中的离子加速进行展望。     

用基态透明的物质进行激光合成超细粉

用ＴＥＡ ＣＯ２激光的被原料吸收谨不被吸收的不同谱线辐照几种物质,如四甲基硅烷,三甲基氯寺烷,六甲基二硅胺烷等,比较其反应情况与产物的异同。认为对于振动基态透明的物质,可以由激光引发气体级联电离的机制生成高活性的低温等离子体从而诱发化学反应,同样可以合成超细粉,而不爱物质吸光性的限制。因此激光方法的原料范围可大为拓宽。本文对影响这类反应和产物的诸因素和激光功率密度、外电场、稀释气体、原料分子的化学     

InSb的电感耦合等离子体刻蚀技术研究

随着InSb红外焦平面探测器的发展,焦平面阵列规模越来越大,像元面积越来越小.湿法刻蚀因其各向同性的特点,导致像元钻蚀严重,越来越难满足大规格InSb焦平面器件的要求.研究了以Ar/CH4/H2作为刻蚀气体,利用电感耦合等离子体(ICP)刻蚀大规格InSb晶片的初步研究结果,研究不同RF功率、腔体压力和Ar的含量对刻蚀速率、表面形貌的影响及InSb表面残留聚合物的去除方法.     

空间磁化等离子体非线性受激电磁辐射进展

电磁波和磁化等离子体的非线性相互作用复杂,高功率电磁波调控电离层实验提供了研究非线性基本问题的主动方式.为构建空间磁化等离子体受激电磁辐射(stimulated electromagnetic emissions,SEEs)体系,本文首先总结了磁化等离子体中可能发生的参量不稳定性;其次,回顾了近十年国际电离层加热激发S...     

平行板静电场法铯离子引出的实验研究

为研究平行板静电场法离子引出的规律，利用对由YAG四倍频脉冲激光(266nm)一步电离产生的铯等离子体进行了多次离子引出实验。结果发现，离子引出时间随外加引出电压的增加而减小，随离子初始密度的增加而增长。通过对实验数据的分析，获得了在此实验条件下光致瞬态铯等离子体离子引出时间与外加引出电压和离子初始密度之间关系的经验公式。但是，离子引出时间并非一直随电压的增加线性减小。在外加电压超过1200V以后发现离子引出时间有增加的趋势。在外加电压高于1000V以后观察到溅射离子峰的存在．并讨论了溅射现象的存在对离子引出时间的影响。通过对离子引出与收集和溅射现象的分析获得了本实验条件下平行板静电场法离子引出中外加电压的最佳值。     

Measurement and analysis of the extreme ultraviolet emission band of laser-produced antimony plasmas

The temporal evolution of extreme ultraviolet (EUV) emission spectra of laser-produced antimony (Sb) plasmas has been measured in the 7–16 nm wavelength region using spatio- temporally resolved lase-produced plasma spectroscopy technique. The spectral profiles involve an intense quasi-continuous band with superimposed intense characteristic radiation and are different with the increase of delay time. The spectral structures were also analyzed according to Hartree–Fock calculations with configuration interaction effects and contributed from 4d–4f, 4d–4p, and 4d–5f unresolved transition arrays of Sb⁷⁺ – Sb¹³⁺. A steady-state collisional- radiative model was used to estimate the electron temperature and density range of Sb plasmas. This work would enrich the spectral data of highly-charged ions and provided a possible selection for developing EUV light sources.     

YAG-MIG复合焊接5A90等离子体光谱分析与温度计算

5A90铝锂合金在航空航天中的重要应用使得对其焊接性的研究变得尤为重要.在YAG-MIG复合焊接5A90的条件下,使用光谱仪对焊接过程中金属蒸气/等离子体进行监测,获得了其特征光谱分布,并由谱线相对强度法计算获得了金属蒸气/等离子体的温度,并对焊接工艺参数对金属蒸气/等离子体温度的影响进行了探讨.结果表明,复合焊接的特征光谱在350～850 nm范围内以大量的高强度的氩离子谱线为主,伴有少量镁、锂离子.得到了一组工艺参数下复合焊接5A90过程中等离子体的平均温度为6 554 K,比同等工艺参数水平下YAG焊的增加了将近1 200 K,而与电弧焊的比较接近.     

Study of Multi-Function Micro-Plasma Spraying Technology

A multi-functional micro-arc plasma spraying system was developed according to aerodynamics and plasma spray theory. The soft switch IGBT （Insulated Gate Bipolar Transistor） invert technique, micro-computer control technique, convergent-divergent nozzle structure and axial powder feeding techniques have been adopted in the design of the micro-arc plasma spraying system. It is not only characterized by a small volume, a light weight, highly accurate control, high deposition efficiency and high reliability, but also has multi-functions in plasma spraying, welding and quenching. The experimental results showed that the system can produce a supersonic flame at a low power, spray Al2O3 particles at an average speed up to 430 m/s, and make nanostructured AT13 coatings with an average bonding strength of 42.7 MPa. Compared to conventional 9M plasma spraying with a higher power, the coatings with almost the same properties as those by conventional plasma spray can be deposited by multi-functional micro-arc plasma spraying with a lower power plasma arc due to an improved power supply design, spray gun structure and powder feeding method. Moreover, this system is suitable for working with thin parts and undertaking on site repairs, and as a result, the application of plasma spraying will be greatly extended.