Silane-Based Coatings on Polypropylene,Deposited by Atmospheric Pressure Glow Discharge Plasmas

The aim of this paper is to show the possibility to synthesize silicon-based deposits on a polypropylene substrate, using a glow dielectric barrier discharge at atmospheric pressure, and to correlate the gas phase behavior with the properties of the thin film deposits. The discharge is generated in a mixture of nitrous oxide and silane, diluted in nitrogen. The influence of the [N₂O]/[SiH₄] ratio on the layer characteristics is mainly studied. Deposits are analyzed by XPS, SSIMS, AFM and wetting angle measurements. The discharges are also characterized by their optical emission spectra. Measurements are made as a function of the distance from the gas inlet, and they allow one to correlate these spectra with the film thickness and its chemical composition. Finally, chemical kinetics of the reactive gas decomposition reactions are proposed.     

Magnetically Enhanced 15 kHz Glow Discharge of Methane

This work deals with the luminous chemical vapour deposition (plasma polymerization) of hydrocarbon polymeric thin films in a magnetic field enhanced discharge of methane. The films were deposited on 4″ <111> single crystal silicon substrates. We investigated the influence of the different glow discharge parameters (e.g. pressure, flow rate, power input, etc.) on the deposition rate of methane and the refractive index of the resulting polymeric films, as well as the distribution of these parameters across the wafer. We used a Shinko Seiki Plasma Polymerization equipment with a bell jar reactor comprising two electrodes connected to a symmetric AC power supply of 15 kHz. Two magnetrons were formed by placing two circular shaped concentric magnetic poles behind each electrode. The substrates were attached on both sides of a rotating wheel held at a floating potential in the middle of the two electrodes. This equipment allowed us to vary a single parameter and keep the other parameters constant over the whole process. We measured the thickness and the refractive index and their distribution over the wafer. The effect of the system pressure, decoupled from the effect of flow rate, is explained by the characteristic nature of luminous gas phase and by the polymerization/deposition mechanism of luminous chemical vapour deposition.     

Air Atmospheric Dielectric Barrier Discharge Plasma Induced Germination and Growth Enhancement of Wheat Seed

Air atmospheric dielectric barrier discharge plasma (DBD) was attempted to pretreat wheat seed to improve its germination and growth in this study. The effects of the DBD plasma treatment on the wheat seed germination, seedling growth, osmotic-adjustment products, lipid peroxidation level, and antioxidant enzymes activity were investigated. The experimental results showed that the DBD plasma treatment with an appropriate time scale could promote the wheat seed germination and seedling growth. The germination potential, germination rate, germination index, and vigor index increased by 26.7, 9.1, 16.9, and 46.9% after 7 min’s DBD plasma treatment, respectively; the root length, shoot length, fresh weight, and dry weight of the seedlings also increased after the DBD plasma treatment. The osmotic-adjustment products, proline and soluble sugar contents, in the wheat seedlings were significantly enhanced after the DBD plasma treatment with an appropriate time scale, while the malondialdehyde content decreased. Moreover, the activities of superoxide dismutase and peroxidase also increased after the DBD plasma treatment. The DBD plasma treatment led to etching effect on the wheat seed coat, resulting in the improvement of its water absorption capacity.     

辉光放电质谱研究与应用新进展

简要介绍了辉光放电的基本原理,主要概述了过去４年有关辉光放电质谱研究的新进展,包括辉光放电质谱的基础研究,新装置和新方法的发展,以及辉光放电质谱的分析应用。文中最后展望了辉光放电质谱法的发展前景。     

Analytical Applications and Fundamental Studies of Microsecond-pulse Glow Discharge Atomic Spectrometry

Since 1970s, research works on the synthesis and studies of novel-type materials have demonstrated a dramatic interest. The physical and chemical characteristics of a new material has a fairly close relationship with the concentrations and distributions of its constitutions, especially the constitutions in the surface of material sample. In addition, the direct analysis of samples in the solid state is of particular importance for ultra-trace elemental methods, for which dissolution of the samples can usually introduce unacceptable impurities. Such an analytical requirement from material science has promoted the developments and applications of glow discharge (GD) atomic spectrometry.     

微波等离子体增强辉光放电光源激发温度的研究

研究了一种改进型的微波等离子体增强辉光放电光源在光谱分析中的应用，对其重要的参数指标－激发温度进行了较为较细的考察。结果表明引入微波等离子体后辉光放电的激发温度明显高于单纯辉光放电时的激发温度。     

Improvement of Seed Germination Rate,Agronomic Traits,Enzymatic Activity and Nutritional Composition of Bread Wheat (Triticum aestivum) Using Low-Frequency Glow Discharge Plasma

Plasma Chemistry and Plasma Processing - Plasma agriculture is an emerging field. In this report, we studied the effect of medium pressure (~?10&nbsp;torr) low-frequency...     

辉光放电质谱法在无机非金属材料分析中的应用

辉光放电质谱法(GDMS)作为一种固体样品直接分析技术,已广泛应用于金属、半导体等材料的痕量和超痕量杂质分析。近年来,随着制样方法和离子源装置的改进,GDMS同样也能很好地应用于玻璃、陶瓷、氧化物粉末等非导体材料的成分分析。简介了GDMS的基本原理和分析特点,概述了GDMS在无机非金属材料分析的方法以及应用情况。     

Anode Magnetron Enhanced DC Glow Discharge Processes for Plasma Surface Cleaning and Polymerization

The objective of this study was to examine some fundamental factors involved in the design and construction of the anode magnetron dc glow discharge processes as well as its performance in plasma cleaning and polymerization. Those advantages of anode magnetron include the capability of the magnetron to operate at low pressure, as well as decreasing the thickness of cathode dark space, i.e., the negative glow which contains a higher concentration of ions and active species was more closely to the cathode surface, which makes the plasma surface cleaning and polymerization an effective and uniform processes. The deposition rate at a given discharge power is increased by the presence of anode magnetrons, and is also much higher relative to rf and af. The refractive index of dc plasma film at a given polymer thickness (such as TMS, 70 nm, RI: 2.4) is higher than rf, af, and cascade arc plasma (RI: 1.6–1.7).     

Enhancement of Germination and Seedling Growth of Wheat Seed Using Dielectric Barrier Discharge Plasma with Various Gas Sources

The influences of non-thermal discharge plasma treatment on wheat seed germination and seedling growth were investigated using a dielectric barrier discharge (DBD) plasma system at atmospheric pressure and room temperature. DBD plasma with various gas sources (oxygen, air, argon, and nitrogen) was employed in this study. Germination characteristics, seedling growth parameters, surface changes of the seed coat, permeability, and soluble protein of the seedlings were measured after the DBD plasma treatments. The experimental results showed that moderate-intensity DBD plasma had active impacts on wheat seed germination and seedling growth. Germination potential significantly increased by 24.0, 28.0, and 35.5% after 4 min of the air plasma, nitrogen plasma, and argon plasma treatments, respectively, compared with the control; and the shoot and root length also increased; however, no enhancement was observed after the oxygen plasma treatment. Scanning electron microscope analysis showed that etching effects on the seed coat occurred after the air plasma, nitrogen plasma, and argon plasma treatments, which affected the hygroscopicity and permeability of the wheat seed. In addition, moderate-intensity DBD plasma could also activate several physiological reactions in wheat seed, resulting in the increase of soluble protein production in wheat seedlings.     

Influence of Solution Conductivity on Contact Glow Discharge Electrolysis

Using a thin platinum anode in contact with an electrolytic solution, normal electrolysis develops spontaneously to contact glow discharge electrolysis (CGDE) at sufficiently high voltage. During this transition, midpoint voltage (V_D) is an important critical value. From V_D on, plasma is sustained by direct current glow discharge between the electrode and the electrolyte surface. And H₂O₂ is the main non-faradaic yield. In this study, effects of conductivity on V_D and the concentration of H₂O₂ have been investigated in Na₂SO₄ and NaCl solution. The results indicate that V_D decreases with the increasing conductivity. And the value of V_D and the concentration of H₂O₂ in NaCl solution are less than those in Na₂SO₄ solution. The concentration of H₂O₂ increases steadily and then decreases to maintain a stationary value.     

On the Nonlocal Electron Kinetics in s- and p-Striations of DC Glow Discharge Plasmas: I. Electron Establishment in Striation-like Fields

The nonlocal behavior of the electrons in strongly modulated and period-averaged electric fields typical of s- and p-striations in neon glow discharge plasmas is investigated by numerically solving the axially inhomogeneous electron Boltzmann equation. A good agreement between the period lengths measured in the striations and those obtained from the spatially periodic electron relaxation in the period-averaged field of the striations is found confirming the close relation of both phenomena. The s- and p-striations represent the fundamental and first harmonics of the inherent periodic electron relaxation. Furthermore, starting from different boundary conditions the establishment of the velocity distribution function and of selected macroscopic quantities of the electrons into unique periodic states under the action of strongly modulated striation-like fields is investigated. It is shown that the same damping processes that cause in homogeneous fields a relaxation into homogeneous states lead to unique periodic states in strongly modulated fields.     

Determination of Minor Aluminum and Nickel in Brass Sample with Magnetic Field Enhanced Glow Discharge Optical Emission Spectrometry

Glow discharge atomic spectrometry, includes principally glow discharge optical emission spectrometry (GD-OES) and GD mass spectrometry, has been widely applied in direct solid sample determination and surface depth analysis. There have been numerous methods adopted to enhance the emission signal in a GD-OES without losing the advantage of narrow spectral lines by using what is known as boosted GD sources, especially microwave discharge and magnetic field enhanced techniques. The addition of a magnetic field to the GD volume is an attractive option because it does not require much modification to the original source configuration, in addition,the presence of magnetic field lengths the drift path of electrons from plasma region to the anode,and therefore strengthens the sputtering, excitation, and ionization processes that good for signal generation.     

On the Nonlocal Electron Kinetics in s and p Striations of DC Glow Discharge Plasmas: II. Electron Properties in Periodic States

The spatial relaxation behavior of the electron gas acted upon by stronglymodulated striation-like electric fields, typically occurring in s and pstriations of dc neon plasmas, has been investigated on a kinetic basis inpart I of this paper. These studies have clearly shown that the electronrelaxation in the striationlike field leads to the establishment of anunambiguous spatially periodic state, which is characterized by largemodulation depths and phase delays of the microscopic and macroscopicquantities with respect to the striationlike field. The present part givesa detailed analysis of these quantities in the established striationlikestates. These investigations clearly reveal the distinctly nonlocal electronproperties, which are especially pronounced in the s-type of striations. Inaddition, the kinetic studies are completed by analyzing the impact of thefield modulation degree and the sensitive destruction of the resonancebehavior of the electron gas when imposing slightly nonresonant electric fields.     

射频供能辉光放电原子发射光谱分析导体的基本特性

自行设计组装了射频供能辉光放电原子发射光谱仪器(rf-GD-AES),并对其分析导体试样的基本特性(包括光源的稳定性、电学特性和光谱特性)进行了研究。在此基础上建立了rf-GD-AES分析导电试样的方法,并用于铜合金标准样品中的A l和Mn的分析,其测定结果与标准值吻合很好,充分地显示了rf-GD-AES在固体样品直接分析中的潜力。     

Deposition of Silver Nanostructures on Polymer Films by Glow Discharge

Plasma Chemistry and Plasma Processing - An atmospheric pressure glow discharge generated between the solid cathode and liquid anode was applied to produce silver nanoparticles and deposition of...     

Glow Discharge Induced Graft Polymerization of Nonvolatile Monomers on Wool

Nonvolatile monomers were grafted to wool by exposure to rf glow discharge under vacuum. The amount of grafting was limited to an average of 2 to 5% weight uptake. With increasing impregnation the amount of graft decreased, and mostly extractable homopolymers formed. Increasing the intensity of the glow discharge above a certain level is also detrimental because at this point the rate of degradation exceeds the rate of polymerization.     

Effects of Cathode and Anode on Deposition of Trimethylsilane in Glow Discharge

DC cathodic polymerization of trimethylsilane (TMS) was carried out in plasma reactors with and without using anode assembly. In DC cathodic polymerization, the TMS plasma polymers are mainly deposited on the cathode (substrate) surface. As a result, fast deposition of TMS plasma polymers was easily achieved in DC cathodic polymerization as compared with AF or RF plasma polymerization. DC cathodic polymerization without using anode assembly has its advantageous features that the size and number of substrates (as cathodes) are not restricted by the size and the location of anode assembly. It was found that the maximum deposition rate on the cathode surfaces was obtained without anode assembly. The DC cathodic polymerization of TMS was conducted also in a large volume reactor with multiple cathodes (substrates). The same deposition mechanisms for DC cathodic polymerization with a single cathode also apply to the multiple cathodes. Uniform deposition on each cathode could be obtained with appropriate spacing of multiple cathodes and by adjusting the operational parameters, which are based on the current density and the system pressure.     

辉光放电等离子体对合成甲醇用铜基催化剂的改性作用

以辉光放电等离子体方法制备了新型高效铜基催化剂, 应用XRD、SEM、H2-TPR、BET、H2-TPD、CO-TPD技术以及对CO加氢合成甲醇反应进行研究, 分析了在氮气、氢气或先氮气后氢气等方式的不同气氛中进行等离子体处理对铜基催化剂的结构和性能的影响. 结果表明, 催化剂前体经等离子体改性处理后, 样品的比表面积增大, 活性中心数增加; 当等离子体气氛为先氮气后氢气时, 催化剂上的CO加氢活性和甲醇的时空产率显著提高.     

介质阻挡放电和CuZSM-5结合体系中等离子体对C2H4的作用

采用吸附、程序升温脱附及氧化和发射光谱等技术研究了介质阻挡放电对气相和催化剂表面吸附乙烯的作用. 实验表明, 介质阻挡放电等离子体能脱附催化剂表面吸附物种(如CO2和H2O等), 并引发表面化学反应生成新物种(如在等离子体作用下C2H4和O2生成CO2和H2O); 改变催化剂表面积碳化合物结构, 并降低其起燃点; 引发气相中乙烯发生反应生成中间物种或碎片(如CN和CH等). 在富氧体系NO/O2/N2中加入C2H4, 能使介质阻挡放电等离子体和CuZSM-5“一段法”结合体系产生协同效应, 提高NOx转化率. 该协同效应的产生与等离子体在气相及催化剂表面引发化学反应, 产生参与NOx还原反应的新稳态物种和短寿命高能活性物种有关.