电子能量对沿面介质阻挡放电等离子体化学产物的影响

基于光电倍增管研制了一套无触发信号的双通道光学探测系统, 并组装了测试样机, 实现了对沿面介质阻挡放电(SDBD)等离子体约化电场的测量, 进而通过BOLSIG+软件获得了电子能量. 采用原位紫外吸收光谱和傅里叶变换红外光谱, 研究了SDBD等离子体在不同电压和频率下的化学产物的浓度变化, 并结合空气等离子体化学反应揭示了产物相互作用的微观机理. 结果表明, 电子能量能够改变电子碰撞反应的速率系数, 调控化学反应的源头活性粒子的浓度, 进而影响到化学产物的生成和猝灭.     

Surface Energy and Adhesive Properties of Polyamide 12 Modified by Barrier and Radio-Frequency Discharge Plasma

Summary. The polyamide 12 foil with sufficient surface and adhesive properties to other substrates can be prepared by discharge plasma modification. For improvement of bonding and printing of polymer a surface barrier discharge plasma in N₂ and O₂ as well as a radio-frequency discharge plasma in air has been studied. A significant increase in surface energy of the polymer as well as in strength of adhesive joint to more polar polymer was found. The chemical changes of PA 12 modified by plasma were analyzed using fourier transform infra red – attenuated total reflection (FTIR–ATR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) measurements. The observed changes of surface properties of the polymer due to aging were not important.     

Surface Energy and Adhesive Properties of Polyamide 12 Modified by Barrier and Radio-Frequency Discharge Plasma

The polyamide 12 foil with sufficient surface and adhesive properties to other substrates can be prepared by discharge plasma modification. For improvement of bonding and printing of polymer a surface barrier discharge plasma in N₂ and O₂ as well as a radio-frequency discharge plasma in air has been studied. A significant increase in surface energy of the polymer as well as in strength of adhesive joint to more polar polymer was found. The chemical changes of PA 12 modified by plasma were analyzed using fourier transform infra red – attenuated total reflection (FTIR–ATR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) measurements. The observed changes of surface properties of the polymer due to aging were not important.     

The Processing of Pyrolysis Fuel Oil by Dielectric Barrier Discharge Plasma Torch

In present paper, an atmospheric-pressure low-temperature plasma treatment of pyrolysis fuel oil (PFO) was investigated in dielectric barrier discharge plasma torch reactor. The effect of the applied voltage and the volume of feedstock, as the main parameters, on the cracking of PFO were studied. By increasing the applied voltage from 10 to 16 kV, the production rate of hydrocarbons containing methane, ethylene, acetylene, propane, propylene, and C₄ rise 18 times. In this case, the production rate of hydrogen increases by approximately 14 times and reaches 7.27 × 10^?3 mol/min for 16 kV. In the feedstock volume investigation, based on limitation of reactor volume, the production rate of hydrocarbons decreased from 0.44 × 10^?3 to 0.15 × 10^?3 mol/min by increasing volume of feedstock from 1 to 5 cc.     

TiOx Films Deposited by Plasma Enhanced Chemical Vapour Deposition Method in Atmospheric Dielectric Barrier Discharge Plasma

The plasma enhanced chemical vapour deposition method applying atmospheric dielectric barrier discharge (ADBD) plasma was used for TiO_x thin films deposition employing titanium (IV) isopropoxide and oxygen as reactants, and argon as a working gas. ADBD was operated in the filamentary mode. The films were deposited on glass. The films?? chemical composition, surface topography, wettability and aging were analysed, particularly the dependence between precursor and reactant concentration in the discharge atmosphere and its impact on TiO_x films properties. Titanium in films near the surface area was oxidized, the dominating species being TiO₂ and substoichiometric titanium oxides. The films exhibited contamination with carbon, as a result of atmospheric oxygen and carbon dioxide reactions with radicals in films. No relevant difference of the film surface due to oxygen concentration inside the reactor was determined. The films were hydrophilic immediately after deposition, afterwards their wettability diminished, due to chemical reactions of the film surface and chemical groups involved in the atmosphere.     

甲烷参与下催化剂填充型介质阻挡放电等离子体脱除NOx

 将In/HZSM-5催化剂填充于介质阻挡放电反应器中,考察了甲烷参与下NOx的脱除及其脱除产物. 结果表明,在200～350 ℃间,等离子体与催化剂共同作用时NOx的转化率明显高于等离子体或催化剂单独作用时NOx的转化率. 在0.03%NO-0.05%CH4-2%O2-97.92%N2,空速7200 h-1和300 ℃的条件下,单纯等离子体、单纯催化剂和二者共同作用下NOx的转化率分别为24%,25%和65%. 甲烷参与下等离子体和催化剂共同作用时,在催化剂表面没有硝酸盐或亚硝酸盐生成,仅有少量副产物N2O生成. 由此可以推断,NOx脱除的主要产物为N2. 低于300 ℃时,NOx的脱除以分解途径为主,甲烷的作用主要是抑制放电条件下NOx生成的副反应; 在300～350 ℃间,甲烷作为还原剂被等离子体和催化剂协同活化,NOx的脱除以还原途径为主. 采用催化剂填充型介质阻挡放电反应器,可在非常宽的温度区间实现NOx的脱除.     

A Dielectric Barrier Discharge Plasma Degrades Proteins to Peptides by Cleaving the Peptide Bond

Plasma Chemistry and Plasma Processing - Effects of atmospheric pressure plasmas on proteins are studied to assess the quality of plasma decontamination and to gain insights into plasma-triggered...     

Scaling for Experimental Inner-Sphere Reorganization Energy of Hydrated Ions via Accurate Potential Function

Reported here are several new calculation methods for the inner-sphere reorganization energy of hydrated metal ions involved in electron transfer processes.It is based on the self-exchange model of reorganization and utilizes the more exact potential functions between central metal ion and the inner-sphere ligands.The parameters involved are determined via the spectroscopic and thermodynamic data.The predictions of the inner-sphere reorganization energies from those models agree well with the photoemission experimental results.     

Plasma Jet and Dielectric Barrier Discharge Treatment of Wheat Seeds

Plasma Chemistry and Plasma Processing - Low-temperature plasma treatment of wheat seeds was performed by a plasma jet and dielectric barrier discharge, both at atmospheric pressure. The influence...     

Effect of Dielectric Barrier Discharge Treatment of Blood Plasma to Improve Rheological Properties of Blood

The whole blood viscosity (WBV) is one of the major independent indicators for the risk of cardiovascular disease, stroke, and peripheral arterial diseases. Furthermore, oxidized LDL molecules are known to cause atherosclerotic plaques in arteries, and it is one of the key components that increase WBV. The present study attempted to reduce WBV by coagulating plasma proteins and lipid molecules from blood plasma using non-thermal dielectric barrier discharge (DBD) and removing them through filtration. The DBD treatment was found to produce coagulated particles in blood plasma. After filtration of the coagulated particles, WBV decreased by 9.1 and 17.7% for both systolic and diastolic blood viscosities, respectively. The present results suggest that the removal of excess plasma proteins and lipid molecules might be feasible using DBD treatment.     

Synthesis of Ozone in a Surface Barrier Discharge with a Plasma Electrode

The synthesis of ozone from oxygen in a cylindrical ozonizer operating under surface discharge conditions with a plasma electrode was studied. The conditions of ozone synthesis were optimized. The dependence of ozone concentration and specific energy consumption on gas pressure in the plasma electrode and on distance between the coils of a corona electrode was determined. The results were compared with data obtained with the use of classical surface barrier discharge.__________Translated from Khimiya Vysokikh Energii, Vol. 39, No. 4, 2005, pp. 307–311.Original Russian Text Copyright © 2005 by Alemskaya, Lelevkin, Tokarev, Yudanov.     

Oxidation of Cyclohexene in the Presence of Alkanes in a Barrier Discharge Plasma

The oxidation of cyclohexene mixtures with hexane, octane, decane, and cyclohexane was studied in a dielectric-barrier discharge reactor. It was shown that a decrease in the partial pressure of cyclohexene in the mixture resulted in a significant increase in the yield of cyclohexene oxide to 75%, with the composition of oxidation products being the same as in the oxidation of individual compounds. A plausible mechanism of the reaction is proposed.     

The Effect of Solvation on Electron Attachment to Pure and Hydrated Pyrimidine Clusters

The interaction of low‐energy electrons with biomolecules plays an important role in the radiation‐induced alteration of biological tissue at the molecular level. At electron energies below 15 eV, dissociative electron attachment is one of the most important processes in terms of the chemical transformation of molecules. So far, a common approach to study processes at the molecular level has been to carry out investigations with single biomolecular building blocks like pyrimidine as model molecules. Electron attachment to single pyrimidine, as well as to pure clusters and hydrated clusters, was investigated in this study. In striking contrast to the situation with isolated molecules and hydrated clusters, where no anionic monomer is detectable, we were able to observe the molecular anion for the pure clusters. Furthermore, there is evidence that solvation effectively prevents the ring fragmentation of pyrimidine after electron capture.     

Plasma Activation of Wood Surface by Diffuse Coplanar Surface Barrier Discharge

Radial cuts of Pedunculate oak (Quercus robur L.) heartwood was activated by Diffuse Coplanar Surface Barrier Discharge (DCSBD) plasma. The plasma treatment resulted in a considerable increase of free surface energy and in the substantial reduction of 50 μl water droplet uptake time. FTIR analysis confirmed the formation of additional polar functional groups on the wood surface due to the plasma treatment. This is consistent with the shift of wood surface pH level towards more acidic values. The energy efficiency of the DCSBD plasma treatment is better comparing to the known volume dielectric barrier discharge treatment method.     

Surface Behavior of Polyamide 6 Modified by Barrier Plasma in Oxygen and Nitrogen

Polyamide (PA) 6 was modified by diffuse coplanar surface barrier discharge (DCSBD) plasma in an atmosphere of nitrogen and oxygen. The surface roughness decrease of PA 6 was detected by AFM and nano-indentation after modification in DCSBD plasma. A significant increase in O/C and N/C ratios of plasma-modified PA 6 using XPS analysis was found. The results show the importance of introducing oxygenic polar functional groups on the polymeric surface in order to increase its surface energy during a short time of plasma activation. The modification of PA 6 by DCSBD oxygen plasma was more efficient than by nitrogen plasma.     

Photochemical Removal of Gaseous Elemental Mercury in a Dielectric Barrier Discharge Plasma Reactor

The plasma process has the potential to serve as a low cost mercury oxidation technology that will facilitate elemental mercury removal in a downstream of Flue Gas Desulfurization system. The performance of the main gas constituents, such as H₂O, O₂ and HCl on elemental mercury oxidation under plasma atmosphere was investigated in simulated flue gas. Experiments were carried out in a dielectric barrier discharge reactor operated at 140?°C. Photochemical effects of nanocrystalline titania on oxidation of elemental mercury were also tested. The results indicated that both H₂O and O₂ promote the oxidation of elemental mercury significantly. Active radicals generated by ionization, such as O, O₂ and OH, play the crucial roles in oxidation process. The presence of HCl in N2/O2 stream in plasma system is a very effective way of oxidizing elemental mercury, the nearly complete oxidation of elemental mercury was observed by 4?kV of applied voltage only. The best photocatalytic activity of anatase TiO₂ which was calcined at 600?°C was found in our tests. Compared with the plasma process alone, the oxidation efficiency increased 18.7?C26.3?% with the addition of photocatalyst.     

乙烷内旋转势垒的从头计算以其能量分解

用ab initio方法以6-31G*为基组对乙烷分子内旋转势垒进行了计算; 用exp-6-1方法对势垒进行了分解。所得势垒与文献报导相符得很好。势垒由总排斥能及色散吸引能两大部分组成, 后者的贡献不重要,其绝对值仅约占3%(图2.4), 这与绝大多数文献报导一致。在总排斥能中,重叠交换、电荷转移、及静电三种相互作用的贡献依次各约占12%、36%及52%(图24)。可见静电排斥在内旋转势垒的形成中占主导作用, 这结论与唐敖庆的分析一致, 而与R.M.Pitzer及Morokuma-Umeyama等的结论不完全一致。结果还表明, 不仅总的势能函数, 而且与组成势垒的各成分相应的势能函数都与Kemp及K.S.Pitzer给出的势函数表达式相符得很好(图3)。     

Oxidative Conversion of PFC via Plasma Processing with Dielectric Barrier Discharges

Perfluorocompounds (PFCs) have been extensively used as plasma etching andchemical vapor deposition (CVD) gases for semiconductor manufacturingprocesses. PFCs have significant effects on the global warming and havevery long atmospheric lifetimes. Laboratory-scale experiments were performedto evaluate the effectiveness of CF4 conversion by using dielectric barrierdischarges (DBD). The results of this study revealed that the removalefficiency of CF₄ increased with application of higher voltage, gas residence time, oxygen content, and frequency. Combined plasma catalysis(CPC) is an innovative way for abatement of PFC and experimental results indicated that combining plasma with catalysts could effectively remove CF4. Products were analyzed by Fourier transform–infrared spectroscopy (FT–IR) and the major products of the CF4 processing with DBD were CO2, COF2, and CO, when O was included in the discharge process. Preliminary results indicated that as high as 65.9% of CF4 was decomposed with CPC operated at 15 kV, 240 Hz for the gas stream containing 300 ppmv CF₄,20% by volume O₂, and 40% by volume Ar, with N₂ as thecarrier gas.     

Measurement of Ozone Production in Non-thermal Plasma Actuator Using Surface Dielectric Barrier Discharge

Plasma actuators for flow control are intensively studied, but the production of ozone by the surface dielectric barrier discharge used in the actuators has never been quantified. Since ozone is harmful to human health, it is important to quantify its production for an application of this type of actuator on a land vehicle. This paper describes an experimental study to measure the concentration of ozone produced by an actuator with different parameters: amplitude and frequency of the applied high voltage, and the electrode configuration (shape, spacing and length). The results show that, under our experimental conditions, the production of ozone is directly proportional to the power dissipation. The production rate was measured at 21 g/kWh. Although the rate is much lower than that of an industrial ozonizer, it is still far from being negligible and should be taken into account for the future application of these actuators.     

Plasma-Aided Cotton Bioscouring: Dielectric Barrier Discharge Versus Low-Pressure Oxygen Plasma

The hydrophobic cuticle of the cotton fiber has formed a natural barrier for pectinase to catalyze its substrates (pectins beneath the cuticle), thus resulting in an insufficient scouring for cotton. Two plasma-based treatments, dielectric barrier discharge (DBD) at atmospheric pressure and cold oxygen plasma at low pressure in a vacuum system, were used as the pretreatments prior to cotton bioscouring, aiming at increasing the accessibility of pectinases to the pectic substances on the cotton fiber. The effects of different processing parameters of DBD and oxygen plasmas on the wettability, whiteness and burst strength of pectinase-scoured cotton were determined and compared. Although both of the pretreatments could enhance cotton bioscouring, DBD might be more suitable for current bioscouring due to its continuous processing mode and lower requirements to the equipment.