High-Temperature Thermodynamic Investigation of Nano-Dispersed Nitrides Obtained in Thermal Plasma

The nitrides of transient metals have a high hardness, thermal stability, remarkable wear resistance in aggressive chemical mediums, melted metals and alloys, high corrosion resistance, and low coefficient of electric resistance. Under the conditions of low-temperature argon plasma （LTP）, thermodynamic investigations were conducted in the process of obtaining of A1N, TiN and Si3N4 in a temperature range of 1000 K to 6000 K. To investigate the thermodynamic possibility of obtaining nitrides, a computer model was used which provided the equilibrium composition of gaseous and solid phases at different temperatures. The conditions for chemical equilibrium of the system were based on the minimization of Gibbs＇ energy.     

Plasma Diagnosis for Microwave ECR Plasma Enhanced Sputtering Deposition of DLC Films

Application of the Langmuir probe in plasma circumstance for deposition of diamond-like carbon （DLC） thin films usually faces the problem of rapid failure of the probe due to surface insulative coating. In this paper, we circumvent the problem by using the floating harmonic probe technique. In the real circumstance of DLC film deposition, the floating harmonic probe worked reliably over 3 hours, correctly indicating the ion density and electron temperature. The technique was practically used to measure the ion density and electron temperature in DLC film deposition processes using the microwave ECR plasma enhanced sputtering. Combined with the Raman spectroscopic characterization of the films, the conditions for deposition of DLC films were investigated.     

Effect of Low Pressure Nitrogen DC Plasma on Optical Properties of Biaxial-Oriented Polypropylene (BOPP), Poly Methyl Methacrylate (PMMA) and Poly Vinyl Chloride (PVC) Films

In this paper properties of Biaxial-Oriented Polypropylene, Poly Vinyl Chloride and Poly Methyl Methacrylate samples treated by DC glow discharge of N₂ plasma have been investigated by UV–Vis_NIR spectrophotometer. It was found that plasma treatment change chemical structure of polymer surfaces. In addition, absorption coefficient, refractive index and extinction coefficient of all treated samples have been slightly changed.     

三种流气式正比计数管的性能比较

主要对现在使用比较多的三种流气式正比计数管做比较,包括外观、坪曲线、效率.通过对比发现不足,改进生产工艺,提高计数管的生产水平,同时可以根据需求选择适当对应的计数管.     

Effect of Low-Pressure Nitrogen DC Plasma Treatment on the Surface Properties of Biaxially Oriented Polypropylene, Poly (Methyl Methacrylate) and Polyvinyl Chloride Films

In this study, commercial biaxially oriented polypropylene (BOPP), polyvinyl chloride (PVC) and poly (methyl methacrylate) (PMMA) films were treated with nitrogen plasma over different exposure times in a Pyrex tube surrounded by a DC variable magnetic field. The chemical changes that appeared on the surface of the samples were investigated using Fourier transform infrared (FT-IR) spectroscopy and attenuated total reflectance Fourier transform infrared (ATR- FTIR) spectroscopy after treatment for 2 min, 4 min and 6 min in a nitrogen plasma chamber. Effects of the plasma treatment on the surface topographies and contact angles of the untreated and plasma treated films were also analyzed by atomic force microscopy (AFM) and a contact angle measuring system. The results show that the plasma treated films become more hydrophilic with an enhanced wettability due to the formation of some new polar groups on the surface of the treated films. Moreover, at higher exposure times, the total surface energy in all treated films increased while a reduction in contact angle occurred. The behavior of surface roughness in each sample was completely different at higher exposure times.     

瞬发伽玛活化分析中3种探测器性能比较

利用中国先进研究堆(CARR)热中子束流孔道首次开展了瞬发伽玛中子活化分析(PGNAA)实验。对NH4Cl、Si、Fe、Al等4种样品进行了辐照,同时采用HPGe、LaBr_3、BGO 3种探测器对样品进行实时测量,在瞬发伽玛射线的能量为0.002~10 MeV范围内研究了3种探测器在宽能区的能量线性、能量分辨率、探测效率等性能。     

Electrical Properties of Plasma Deposited Low-Dielectric-Constant Fluorinated Amorphous Carbon Films

Fluorinated amorphous carbon （a-C：F） films were deposited at room temperature using C4Fs and CH4 as precursor gases by electron cyclotron resonance chemical vapour deposition （ECR-CVD）. Chemical structures were analysed using X-ray photoelectron spectroscopy （XPS）. The current conduction shows ohmic behaviour and the leakage current increases with the content of C sp2 in the deposited a-C：F films at a low electric field. The behaviour of the leakage current is well e~plained by the Poole-Frankel mechanism at a high electric field. The interface traps, rather than chemical structures, of a-C：F films determine the PF emission current.     

Study of SiO_2 Films Prepared by Electron CyclotronResonant Microwave Plasma

1.IntroductionInoptIcaltelecommunlcatlons,ltisnecessarytodevelopoptlcalfibresystemswithhighertransmls-sionefficlencyandnetworkflexlblllty.Todate,hott'-ever,theyhavebeenfarfromreallzation,baslcallybecauseofdifficultiesinprocessesoffabricatingpla-naropticalwaveguidesanddeviceswithlowbendandtransmlsslonlosses[l1.Whicharedirectlyre-liedonopticalwaveguidefilmperformancesuchashighrefractiveindexandlowsurfaceroughness.Assilicafilmsarecapabletobedepositedoncrystallinesiliconsllbstrateandfurtherformac…     

High-Pressure Plasma Deposition of a-C：H Films by DielectricBarrier Discharge

The fabrication of a-C:H films from methane has been performed using dielectric-barrier discharges at atmospheric pressure. The effect of combined-feed gas, such as carbon dioxide, carbon monoxide or acetylene on the formation of a-C:H films has been investigated. It has been demonstrated that the addition of carbon monoxide or acetylene into methane leads to a remarkable improvement in the fabrication of a-C:H films. The characterization of carbon film obtained has been conducted using FT-IR, Raman and SEM.     

Argon/Hexamethyldisiloxane Plasma Effects on Poly Propylene Film Surface Properties

In this work a DC plasma reactor was used for deposition of plasma polymerized coating from hexamethyldisiloxane–Ar (35/65%) mixture on polypropylene films. Surface energy parameter have been calculated using Owens–Wendt approaches with the sessile drop method are used to obtain the dispersive γ^D and polar γ^P component of surface free energy. The surface morphology of samples were investigated using scanning electron microscope. Also the chemical properties and wetability of prepared samples were tested using Fourier transform infrared spectroscopy and contact angle measurement, respectively.     

Using Mather-Type Plasma Focus Device for Fabrication of Tungsten Thin Films

Tungsten (W) thin films were deposited on stainless steel–304 substrates using a low energy (2?kJ) plasma focus device. The samples were synthesized at various distances with respect to anode tip (7, 10 and 13?cm) and using same number of focus deposition shots (25 shots). X-ray diffraction (XRD), energy dispersive X-ray atomic force microscopy (AFM) and micro hardness were used to investigate the prepared samples. XRD analysis revealed that the degree of crystallinity of deposited thin films decrease with increasing the distance from the anode tip. AFM results showed that size of the grains on the surface of the films and the surface roughness of deposited samples constantly increase with the increasing of the axial position. Moreover, the hardness measurements revealed that the highest mechanical hardness is obtained when the film is deposited at 7?cm axial position.     

Plasma Parameters of a Gliding Arc Jet at Atmospheric Pressure Obtained by a Line-Ratio Method

A generator of the gliding arc jet (GAJ), which is driven by a transverse magnetic field, is developed to produce non-equilibrium plasma at atmospheric pressure. The gas temperature is estimated using the spectrum of OH radicals to be about 2400±400 K. The determinations of electron temperature and electron density by using a line-ratio method are elaborated for the gliding arc jet plasma. This line-ratio method is based on a collisional-radiative model. The experiment results show that electron temperature is about 1.0 eV and electron density is about 6.9×1014 cm-3 . Obviously, the plasma of GAJ is in a non-equilibrium state.     

三种堆型核燃料循环经济性比较

本文详细地分析了压水堆、高温气冷堆、快堆三种堆型核电厂的燃料循环过程,建立了燃料循环费用的计算模型和灵敏度分析模型。对三种堆型的核燃料费用进行了分析比较,指出快堆是燃料费用最经济的堆型。     

Error Estimation of Values Obtained from Practical CFD Analysis

In recent years, it has become common to analyze the detailed, three-dimensional flow features in reactor pressure vessels of boiling water reactors (BWRs) by computational fluid dynamics (CFD) analysis. However, there are few reports on practical examples of estimation or on estimation methodologies of the uncertainties in multi-dimensional CFD analysis. In this paper, to estimate the errors of values obtained from practical CFD analysis of a complex flow field, we propose a quantitative methodology that adopts the numerical analysis errors of “elementary phenomena” as error factors for sensitivity analyses, as well as, for instance, dimensional tolerances or errors of input values. Using this methodology with CSAU methodology, we showed a practical simplified example of error estimation regarding calculated water surface drop along the radial direction obtained from CFD analysis of the hydraulic gradient formed in the reactor pressure vessel of a BWR. We show the validity of the methodology by comparing this “estimated error” with a “reference error” evaluated by comparing numerical and experimental results.     

聚乙烯醇膜材料氚衰变辐照效应研究

利用FTIR、XRD、AFM等方法,分析了聚乙烯醇（PVA）膜材料在不同氚气氛下的氚衰变辐照效应,表征了氚衰变β射线对PVA中氢与氚同位素置换的诱导激化作用,明确了PVA中的氚取代主要发生在C-H基团,而醇羟基O-H基团因强烈的氢键作用而未发生氚取代;材料的表面形貌、结晶度等均发生了变化。通过PVA膜拉伸力学性能实验,测定了不同氚衰变辐照下PVA膜材料的拉伸强度和伸长率。结果显示,与其微观结构变化趋势一致。     

Cytotoxicity of Boron-Doped Nanocrystalline Diamond Films Prepared by Microwave Plasma Chemical Vapor Deposition

Boron-doped nanocrystalline diamond(NCD) exhibits extraordinary mechanical properties and chemical stability,making it highly suitable for biomedical applications.For implant materials,the impact of boron-doped NCD films on the character of cell growth(i.e.,adhesion,proliferation) is very important.Boron-doped NCD films with resistivity of 10~(-2)Ω·cm were grown on Si substrates by the microwave plasma chemical vapor deposition(MPCVD) process with H_2 bubbled B_2O_3.The crystal structure,diamond character,surface morphology,and surface roughness of the boron-doped NCD films were analyzed using different characterization methods,such as X-ray diffraction(XRD),Raman spectroscopy,scanning electron microscopy(SEM) and atomic force microscopy(AFM).The contact potential difference and possible boron distribution within the film were studied with a scanning kelvin force microscope(SKFM).The cytotoxicity of films was studied by in vitro tests,including fluorescence microscopy,SEM and MTT assay.Results indicated that the surface roughness value of NCD films was 56.6 nm and boron was probably accumulated at the boundaries between diamond agglomerates.MG-63 cells adhered well and exhibited a significant growth on the surface of films,suggesting that the boron-doped NCD films were non-toxic to cells.     

Synthesis of Diamond-Like Carbon Films Using Hot Filament-Aided Microwave Plasma Chemical Vapor Deposition

1. IntroductionDiamond-like carbon (DLC) films have receivedconsiderable attention recently because their inher-ent properties such aJs hardness, thermal conductiv-ity and electrical resistance are excellent and closeto those of a diamond. The DLC films have beenprepared by a variety of methods, for instance, radiofrequency (RF) plasma deposition [l], ion beam de-position [2] and electron cyclotron resonance (ECR)chemical vapor deposition [3]. As sllrface wave dis-charges [4] have advanta…