容性耦合射频（CCRF）放电等离子体特性实验研究

利用自行研制的传感器和测量装置，通过对放射频放电电压电流以及其相位角的测定，算出放电算的总阻抗，结合放电管的等效电路，对容性耦合射频（CCRF）激励激光放电特性进行研究，得出容性耦合射频激励激光器等离子体的伏安特性的曲线，以及等离子体电阻，容抗与气体压器，放电电流之间的实验曲线，在Godyak射频放电模型的基础上得出等离子体的电子密度，并同内置铜电极射频激励铜离子激光器阻抗特性进行了比较。     

干法刻蚀中射频等离子体电特性的研究

射频功率为５０－５００Ｗ（１３．５６ＭＨＺ），气压为１．３－１３．３Ｐａ的氩和四氟化碳放电气气氛中，测量了阻抗、直流自偏压和峰－峰电压。测量结果表明，这种放电可以采用容的电阻的串、并联来描述。同时研究了离子轰击两个电极的能量比率，指出过去被广泛假设的离子轰击能量的比率与电极面积比的四次方关系并不相符。     

容性耦合射频(CCRF)放电等离子体特性实验研究

利用自行研制的传感器和测量装置 ,通过对射频放电电压电流以及其相位角的测定 ,算出放电管的总阻抗 ,结合放电管的等效电路 ,对容性耦合射频 (CCRF)激励激光器放电特性进行研究 ,得出容性耦合射频激励激光器等离子体的伏安特性的曲线 ,以及等离子体电阻、容抗与气体压强、放电电流之间的实验曲线 ,在Godyak射频放电模型的基础上得出等离子体的电子密度 ,并同内置铜电极射频激励铜离子激光器阻抗特性进行了比较。     

干法刻蚀中射频等离子体电特性的研究

射频功率为50～500W（1．56MHz）、气压为1．3～13．3Pa的氩和四氟化碳放电气氛中，测量了阻抗、直流自编压和峰－峰电压。测量结果表明，这种放电可以采用电容与电阻的串、并联来描述。同时研究了离子轰击两个电极的能量比率，指出过去被广泛假设的离子轰击能量的比率与电极面积比的四次方关系并不相符。     

用于CTCP技术的射频无电极放电氮气等离子体光源研究

本文报道了一种利用射频无极放电激励的氮气等离子体新型光源,成功地对“星光”PS版进行了曝光,光谱分析表明氮气射频放电光源的光谱结构较碘镓灯更适于传统PS版曝光。为此,进一步从射频功率、工作气压等方面探讨了光源的最佳运行参数,得到在230Pa、160W、采用两个传输透镜聚焦后获得的光源功率密度是2.23mW/cm^2。最后给出了运用此光源对PS版的曝光结果。     

射频无电极放电氮气等离子体光源研究

本文报道了一种利用射频无电极放电激励的氮气等离子体新型光源，测出了辐射光谱、光功率、工作气压等光源相关参数，优化实验条件得出的电光转换效率达22．05％。最后运用此光源成功的对一种印刷预涂感光版（pre-sensitive plate，PS版）进行了曝光，通过曝光前后PS版感光层颜色的光密度变化评价了感光效果。     

大气压射频单介质阻挡放电中放电通道收缩现象的研究

大气压射频辉光放电产生的等离子体具有温和的温度、较好的稳定性和较强的化学活性而广泛应用于工业生产、生物处理等领域。为提高工作效率、增加放电均匀性, 应避免产生放电收缩现象。为此, 设计了一个带水冷铜电极的射频单介质阻挡放电系统, 在大气压下研究氮气和氩气放电收缩形成的机制。纳秒级ICCD相机拍摄的放电图像揭示出在大气压下氮气和氩气放电中明显存在放电通道收缩现象, 在放电周期内放电通道形状保持不变, 但在不同位置的发光强度随射频电源的频率作周期性变化。通过分析放电图像的三维时空分辨图和二维时间分辨图, 发现上下电极表面附近的发光强度在一个射频周期内交替出现一个峰, 但峰出现时间上为非对称。这不同于射频裸电极放电, 也不同于射频双介质阻挡放电。分析认为发光强度峰在一个射频周期内交替出现的时间非对称性是由于非对称电极表面电荷积累和二次电子发射差异造成。     

大气压射频均匀辉光放电的条件

大气压放电应用在很多领域时,其放电的均匀性显得十分重要。本文通过实验得出影响大气压射频放电的均匀性的条件。实验中研究的影响因素有介质阻挡、放电电压、放电气体组成以及放电间隙。实验采用单反照相机以及ICCD照相机对放电进行拍照,观察不同参数放电下的放电模式。通过放电现象发现对维持大面积均匀辉光放电影响最大的因素是采用介质阻挡和放电气体的组成,影响较小的是放电电压。放电间隙在可维持放电的间隙范围内对放电模式影响很小。实验得出,改变这些条件会使均匀辉光放电中出现放电丝,或完全转变为丝状放电甚至熄灭。     

射频辉光放电中的自生负偏压

本文讨论了射频自偏压产生的机理，并认为以射频自偏压作为射频光放电系统的最重要的工艺参数是有道理的。     

射频激励CO2波导激光器的放电技术

本在理论上详细论述了如何在激光头的射频电极上并联上一些电感，并在激光头和电源之间加一可调匹配网络以达到这一目的，并在实验上实现了矩形波导以及１＊３波导列阵大面积的均匀放电，得到了激光输出。     

Nitridation of aluminum particles and formation process of aluminum nitride coatings by reactive RF plasma spraying

Nitridation of aluminum particles and formation process of aluminum nitride coatings by reactive RF plasma spraying was investigated by collecting splat and depositions and fabrication of the coating. Nitriding reaction of aluminum particles during flight in the plasma and after deposit on the substrate was confirmed by the observation of splats and the deposition morphologies, respectively. However, as nitriding reaction of aluminum particles easily forms brittle agglomerates on the substrate, the formation of sound coating was difficult. Though the coating was fabricated with the spraying condition of RF power of 5 kW, it was impossible to fabricate the coatings with RF power of 6 kW. In order to fabricate aluminum nitride coatings by reactive RF plasma spraying, it is necessary to control the plasma and the substrate temperature for the suitable conditions with changing RF power and nitrogen gas flow rate.     

Double layer onset inside the near-electrode sheath of a RF capacitive discharge in oxygen

This paper reports the axial profiles of the electron temperature T_e in the RF capacitive discharge in oxygen recorded with a probe technique. We observed the T_e peaks near the boundaries of the sheaths as well as inside the near-electrode sheath. The T_e peak inside the sheath is, probably, due to the formation of the double layer at the anode phase of this near-electrode sheath. The assumption of a double layer formation is also supported by the photos of the sheath glow making evident the bright region inside the sheath. The results of our measurements agree with our fluid simulation satisfactorily.     

Preparation and characterization of carbon nano-onions by nanodiamond annealing and functionalization by radio-frequency Ar/O2 plasma

Carbon nanomaterials can be prepared by several methods having in common that need a carbon source and often require high energies. In this study, we report the synthesis and characterization of carbon nano-onions by annealing of commercially available nanodiamonds and explore for the first time their functionalization with a radio frequency Ar/O₂ plasma. Heat treatment of nanodiamonds at 1200°C for 6 hours under argon atmosphere afforded small spherical carbon nano-onion particles of 3–4 nm diameter and 5–6 graphitic shells. The prepared CNOs were visualized by HRTEM and showed the characteristic XRD and Raman features. The results have been compared with a sample prepared by annealing at 1600°C. Plasma functionalization in Ar/O₂ atmosphere was used to introduce oxygen moieties into the surface of synthesized CNOs. X-ray photoemission spectroscopy showed that oxygen-containing groups like C─O, C═O and O─C═O were introduced on the surface of CNOs, a process that is accompanied by a surface reorganization as evidenced by the change of I_D/I_G ratios in the Raman spectra, indicating a conversion of sp² to sp³ as a result of functionalization in the surface of CNO.     

Current and Voltage Measurements in the Gaseous Electronics Conference RF Reference Cell

Measurements of the electrical characteristics of discharges in the Gaseous Electronics Conference Radio-Frequency Reference Cell are reviewed here. Topics include: common sources of error in the measurements; comparisons of current and voltage data among GEC cells; the effects of gas impurities, surface conditions and the external circuitry on the reproducibility of the electrical characteristics; and comparisons of current and voltage data with results of other measurements.     

Formation of ZnO nanostructures in energy-controlled hollow-type magnetron RF plasma

In this study, we investigated how zinc, sputtered from a zinc target, reacts with oxygen on the substrate to form ZnO nanostructures when the discharge parameters, such as gas flow ratio and target bias voltage, are controlled in O₂/Ar plasma. The deposits were estimated by SEM and Raman spectroscopy. Under conditions of a Zn to Ar optical emission intensity ratio of 2/1, a target voltage of − 550 V, a total pressure of 40 Pa, a substrate temperature of 150 °C, an RF power of 50 W, and a deposition time of 30 min, many vertically aligned ZnO nanorods were observed to be deposited on the substrate. The diameter of the rods was typically 50 nm. It was found that the film morphology can be controlled by the sputtering rate of zinc varied by the target bias voltage and gas flow rate.     

射频等离子体球化SiO2粉体的研究

采用射频等离子体球化颗粒形状不规则的二氧化硅粉体,研究了加料速率、颗粒大小等因素对球化率的影响.用光学显微镜观察球化前后颗粒的形貌;用流动仪测定球化后粉体的松装密度.结果显示,球化后的二氧化硅颗粒球形度高,细颗粒长大,并且随着球化率的增大粉体松装密度增加.初步查明加料速率、原料粒度等参数对球化率的影响.在适当的条件下可以得到球化率高、球形度好的粉体.     

Electrode wear phenomenon and its compensation in micro electrical discharge milling: A review

Micro electrical discharge machining (µEDM) is playing a significant role in the world of miniaturization, especially in micro electro mechanical systems, biomedical devices, micro die/molds, etc. Micro electrical discharge milling (µED-milling) is a variant of µEDM used for producing complex 3D features with a simple shaped tool. The material removal mechanism of µEDM depends on electro-thermal energy between the tool electrode and workpiece. µEDM inherently being a non-contact machining process, leads to produce miniaturized features in hard to machine materials. Besides erosion of the workpiece material, intrinsic feature of the process leads to tool wear (TW) and introduces dimensional inaccuracy in the micro features. Thus, it is essential to know the factors influencing the TW, and thereby compensate the TW to achieve dimensional stability of the machined features. The critical factors affecting the wear phenomenon of a tool and various techniques applied to compensate TW in µED-milling along with future trends of their application are presented. The key issues of µED-milling and challenges faced in implementing a TW compensation technique are highlighted. The concept of intentional wear of tool electrode and associated advantages in EDM is also demonstrated.     

Production of high density and low electron-temperature plasma by a modified grid-biasing method using inductively coupled RF discharge

A noble method for the production of high density and low electron temperature plasma is presented. In plasma enhanced chemical vapor depositions, electron temperature affects the quality of deposited films, so a low-electron-temperature plasma is required to reduce excess dissociated radicals. Here, a grid-biasing method is modified and improved to produce high-electron-density and low-electron-temperature plasmas to increase deposition speed. As a result, the electron temperature is lowered in a range of 0.1-0.5 eV and the electron density is raised from the order of 10⁹ to ∼2×10¹¹ cm⁻³.     

Spheroidisation of tungsten powder by radio frequency plasma for selective laser melting

The growing interest in additive manufacturing of refractory metals is accompanied by the demand on spherical refractory meal powders with good flowability. In this work, the particle size distribution, particle morphology, phase and extent of oxidation of the tungsten powders spheroidised by radio frequency (RF) plasma with different feeding rates were investigated using scanning electron microscopy, laser particle size analysis and X-ray diffraction. It was demonstrated that spherical tungsten powders with extremely fine flowability and high apparent density were obtained by the RF plasma spheroidisation technology. High-density tungsten samples with negligible defects were prepared with the spheroidised powders by selective laser melting. The results would help pave the way for solving the problems in customising refractory metal parts by additive manufacturing.     

钻机底座模态试验的一种简便方法

地钻机底座进行模态试验,往往由于工作环境的限制和需要测点较多,给测试工作带来很大不便;根据模 态分析理论,提出了模态测试的一种简便方法,即选取钻台面上合适的部分进行模态测试和分析,并将分析结果应用于 整个底座结构;在ZJ15型钻机底座模型上进行的模态试验结果的对比分析,验证了方法的可行性。