低压促进的金刚石薄膜的低温生长

本文研究了气压对热丝化学气相沉积金刚石薄膜沉积温度的影响.扫描电子显微镜(SEM)结果表明,同常规热丝化学气相沉积的气压(5.32 kPa)相比,采用较低的气压(0.67 kPa)、在500℃的低温下可获得常规气压下不大容易获得的、小颗粒的金刚石薄膜.Raman结果进一步证实了这种薄膜具有同5.32 kPa、700℃条件下沉积的薄膜的可比拟的质量.低温低压下高质量的金刚石薄膜的获得同气压在决定衬底表面的碳氢分子活性基团浓度的两种相反的作用密切相关.同相同温度其它气压条件相比,在500℃的衬底温度、0.67 kPa气压下到达衬底表面的碳氢分子活性基团具有较高的浓度,从而导致了常规气压下不大可能获得的高质量,小颗粒金刚石薄膜的低温沉积.     

基于单一气源的PECVD方法制备SiC薄膜及其微观结构研究

为制备出满足惯性约束聚变(ICF)实验要求的SiC薄膜,本文采用等离子体增强化学气相沉积(PECVD)法,以四甲基硅(TMS)作为唯一反应气源,在不同工作压强下制备SiC薄膜。利用扫描电子显微镜、表面轮廓仪、原子力显微镜、精密电子天平、X射线光电子能谱、傅里叶变换红外光谱对薄膜进行表征与分析。结果表明：SiC薄膜的成分与工作压强密切相关,随着工作压强的增加,薄膜中Si含量整体呈下降趋势;随着工作压强的增加,薄膜沉积速率先增大后减少,密度先减小后增大;与其他制备工艺相比,采用单一气源制备SiC薄膜,其表面粗糙度极低(1.25～1.85 nm),薄膜粗糙度随工作压强的增加呈先增大后减小的趋势。     

基于单一气源的PECVD方法制备SiC薄膜及其微观结构研究

为制备出满足惯性约束聚变（ICF）实验要求的SiC薄膜,本文采用等离子体增强化学气相沉积（PECVD）法,以四甲基硅（TMS）作为唯一反应气源,在不同工作压强下制备SiC薄膜。利用扫描电子显微镜、表面轮廓仪、原子力显微镜、精密电子天平、X射线光电子能谱、傅里叶变换红外光谱对薄膜进行表征与分析。结果表明：SiC薄膜的成分与工作压强密切相关,随着工作压强的增加,薄膜中Si含量整体呈下降趋势;随着工作压强的增加,薄膜沉积速率先增大后减少,密度先减小后增大;与其他制备工艺相比,采用单一气源制备SiC薄膜,其表面粗糙度极低（1.25～1.85 nm）,薄膜粗糙度随工作压强的增加呈先增大后减小的趋势。     

CHN薄膜的制备

文章简要描述了空心阴极等离子体化学气相沉积(HPCVD)的原理，以及用HPCVD方法制备CHN薄膜的工艺和实验结果。用XPS和AFM分别分析了CHN薄膜中C和N的成分及表面形貌，并得到了一定条件下的薄膜沉积速率。     

多晶硅薄膜等离子体增强化学气相沉积低温制备工艺

采用电子回旋共振等离子增强化学气相沉积(ECR-PECvD)方法,以SiH4和H2为气源,在普通玻璃衬底上沉积多晶硅薄膜.利用XRD、Raman光谱和TEM研究了衬底温度、氢气流量和微波功率对多晶硅薄膜结构的影响.结果表明,制得的多晶硅薄膜多以(220)取向择优生长,少数条件下会呈现(111)择优取向.当衬底温度为300℃、H2流速为25 mL/min、微波功率为600 W时,多晶硅薄膜结晶状态最好,且呈最佳的(220)取向.     

高功率脉冲非平衡磁控溅射制备CrNx薄膜及其性能研究

高功率脉冲磁控溅射技术(HPPMS)溅射粒子离化率高,可沉积致密、高性能薄膜,作为一种新技术在国外广泛研究。本文用高功率脉冲非平衡磁控溅射技术(HPPUMS)制备一系列CrN_x薄膜,采用原子力显微镜(AFM)和X射线衍射(XRD)对不同厚度的薄膜表面形貌、微观结构进行了分析,测定了薄膜的厚度和硬度,研究了薄膜的摩擦学性能,并与中频磁控溅射(MFMS)技术制备的CrN_x进行比较。结果表明,使用高功率脉冲非平衡磁控溅射技术(HPPUMS)能制备致密的CrN_x薄膜。薄膜有较好的综合性能,有较高硬度、较高结合强度和低摩擦系数。     

脉冲激光沉积薄膜生长机制的计算机模拟研究

建立了一个分子动力学模型以研究脉冲激光沉积金属薄膜的成膜过程，探讨激光沉积中极主的瞬时沉积率和载能粒子轰击对成模机制的影响，以能量为１０ｅＶ的Ｃｕ原子入射到Ｃｕ（１００）表面为例，进行了分子动力学模拟的计算，结果表明，激光成膜过程中载能粒子的瞬时高能量沉积极大地增加了外延表面的原子扩散活性，促使薄膜能在低温下以原子层尺度逐层生长。     

铀上激光辅助化学气相沉积镍薄膜研究

为防止金属铀的腐蚀,本文采用激光辅助化学气相沉积(LACVD)方法在铀上制备了镍薄膜。采用SEM、XRD分析了薄膜的形貌、物相以及界面特性,采用黏胶拉伸测试表征了膜-基结合性能,采用电化学极化法分析了薄膜的抗腐蚀性能。结果表明:压力和温度对化学气相沉积(CVD)方法制备镍薄膜的质量有较大的影响。随着基底温度和沉积气压的降低,薄膜变得致密、平整,质量提高。在优化的工艺条件165℃、3Pa下,CVD方法所得镍薄膜非常致密。采用LACVD方法时,激光能量为200mJ时所制得的薄膜致密,300mJ时膜变得粗糙。无激光辅助时,CVD方法所制得的薄膜较易剥落,激光辅助下所得薄膜的膜-基结合力较好。LACVD方法大幅提高了薄膜的抗腐蚀性能,抗腐蚀性能的提高主要源于激光辅助使薄膜致密化,提高了薄膜与基底的结合力。     

氧化石墨烯薄膜的自组装制备与伽玛射线辐照还原

通过改进的水浴自组装技术,制备出由氧化石墨烯纳米片组成的氧化石墨烯（Graphene oxide,GO）薄膜,对该薄膜进行γ射线辐照后采用扫描电子显微镜（SEM）、X射线衍射光谱（XRD）对辐照前后的薄膜进行表征,分析辐照对GO薄膜的改性作用。结果表明,辐照后GO薄膜的层间距由0．94nm减小到0．80nm,薄膜中GO纳米片的平均厚度从1．69nm减小到0．86nm,证明了γ射线对GO薄膜良好的还原效应,使GO纳米片的层间官能团减少并导致了层间距和厚度减小。本文还探讨了γ射线辐照对GO薄膜的还原机理。     

MOCVD制备的氮化铪薄膜结构特性研究

以热氧化的p型硅(SiO2/Si)为衬底,运用金属有机化学气相淀积(MOCVD)技术以铪基金属有机源和高纯氨为反应气体在其上淀积HfNx薄膜样品。薄膜结构信息用RBS技术、XRD技术及X射线反射率(XRR)计等来表征。实验结果表明,HfNx薄膜中N与Hf原子组分比为1.15;薄膜为多晶薄膜且沿(111)方向择优生长;薄膜表面平整,与衬底界面粗糙度小。     

Microwave Plasma Chemical Vapor Deposition of Diamond Films on Silicon From Ethanol and Hydrogen

Diamond films with very smooth surface and good optical quality have been deposited onto silicon substrate using microwave plasma chemical vapor deposition(MPCVD)from a gas mixture of ethanol and hydrogen at a low substrate temperature of 450℃.The effects of the substrate temperature on the diamond nucleation and the morphology of the diamond film have been investigated and observed with scanning electron microscopy(SEM).The microstructure and the phase of the film have been characterized using Raman spectroscopy and X-ray diffraction(XRD).The diamond nucleation density significantly decreases with the increasing of the substrate temperature.There are only sparse nuclei when the substrate temperature is higher than 800℃ although the ethanol concentration in hydrogen is very high.That the characteristic diamond peak in the Raman spectrum of a diamond film prepared at a low substrate temperature of 450℃ extends into broadban indicates that the film is of nanophase.No graphite peak appeared in the XRD pattern confirms that the film is mainly composed of SP^3 carbon.The diamond peak in the XRD pattern also broadens due to the nanocrystalline of the film.     

Parameter Optimization for Enhancement of Ethanol Yield by Atmospheric Pressure DBD-TreatedSaccharomyces cerevisiae简

In this study, Saccharomyces cerevisiae （S. cerevisiae） was exposed to dielectric barrier discharge plasma （DBD） to improve its ethanol production capacity during fermenta- tion. Response surface methodology （RSM） was used to optimize the discharge-associated pa- rameters of DBD for the purpose of maximizing the ethanol yield achieved by DBD-treated S. cerevisiae. According to single factor experiments, a mathematical model was established using Box-Behnken central composite experiment design, with plasma exposure time, power supply volt- age, and exposed-sample volume as impact factors and ethanol yield as the response. This was followed by response surface analysis. Optimal experimental parameters for plasma discharge- induced enhancement in ethanol yield were plasma exposure time of 1 rain, power voltage of 26 V, and an exposed sample volume of 9 mL. Under these conditions, the resulting yield of ethanol was 0.48 g/g, representing an increase of 33% over control.     

Characterization of Crystalline Nanoparticles/Nanorods Synthesized by Atmospheric Plasma Enhanced Chemical Vapor Deposition of Perfluorohexane

A mass of nanoparticles/nanorods were formed on a simultaneously deposited gran- ular film by plasma enhanced chemical vapor deposition （PECVD） of perfluorohexane at atmo- spheric pressure without any catalysts or templates. Scanning electron microscopy （SEM） and X-ray photoelectron spectroscopy （XPS） were used to characterize the morphology and the chem- ical compositions of nanoparticles. The average size of particles is about 100 nm and the length of synthesized nanorods is between 1 μm and 2.5/tm. The analyses of transmission electron microscopy （TEM）, high-resolution transmission electron microscopy （HRTEM）, selected area electron diffraction（SAED） and X-ray diffraction （XRD） reveals that the nanoparticles and nanorods are crystalline.     

Deposition of Thin Titania Films by Dielectric Barrier Discharge at Atmospheric Pressure

A homogeneous atmospheric pressure dielectric barrier discharge is studied. It is in argon with small admixtures of titanium tetrachloride vapour and oxygen for the deposition of thin titania films on glass substrates. A special electrode configuration was applied in order to deposit the titania film uniformly. The sustaining voltage （6 kV to 12 kV）, current density （about 3 mA/cm^2） and total optical emission spectroscopy were monitored to characterize the discharge in the gap of 2 mm. Typical deposition rates ranged from approximately 30 nm/min to 120 nm/min. The film morphology was investigated by using scanning electron microscopy （SEM） and the composition was determined with an energy dispersive x-ray spectroscopy （EDS） analysis tool attached to the SEM. The crystal structure and phase composition of the films were studied by x-ray diffraction （XRD）. Several parameters such as the discharge power, the ratio of carrier gas to the precursor gas, the deposition time on the crystallization behavior, the deposition rate and the surface morphology of the titania film were extensively studied.     

以乙醇为介质气体扩散法分离碳同位素的可行性研究

碳-13作为同位素示踪技术的标记物,应用广泛,市场需求呈上升趋势。为探索碳-13同位素的分离方法,开展以乙醇为介质的气体扩散分离实验,并在单级实验的基础上进行级联计算。单级分离实验的结果表明,在现有的实验条件下,气体扩散法分离乙醇的基本全分离系数可达1.0089,以乙醇为介质扩散分离碳同位素可行。通过级联计算可知,以天然乙醇为原料,结合分离的可行性和经济性,经过一次矩形级联或相对丰度匹配级联分离,能够得到碳-13同位素丰度大于25%的重组分。如能将碳-13同位素丰度大于25%的乙醇转化为合适形态的碳化合物,可再进一步分离得到更高丰度的碳-13同位素。     

以乙醇为介质气体扩散法分离碳同位素的可行性研究

碳-13作为同位素示踪技术的标记物,应用广泛,市场需求呈上升趋势。为探索碳-13同位素的分离方法,开展以乙醇为介质的气体扩散分离实验,并在单级实验的基础上进行级联计算。单级分离实验的结果表明,在现有的实验条件下,气体扩散法分离乙醇的基本全分离系数可达1.0089,以乙醇为介质扩散分离碳同位素可行。通过级联计算可知,以天然乙醇为原料,结合分离的可行性和经济性,经过一次矩形级联或相对丰度匹配级联分离,能够得到碳-13同位素丰度大于25%的重组分。如能将碳-13同位素丰度大于25%的乙醇转化为合适形态的碳化合物,可再进一步分离得到更高丰度的碳-13同位素。     

用于ICF的非晶SiC微球制备及微观结构研究

以四甲基硅烷、反式二丁烯和氢气为工作气源,采用化学气相沉积-高温热解法成功制备了壁厚约21μm的非晶SiC微球。利用能量色散X射线光谱仪、X射线光电子能谱仪、X射线衍射仪、Raman光谱仪、扫描电子显微镜、白光干涉仪和X射线照相机对SiC微球的化学成分、结晶状态、表面形貌与粗糙度以及密度与球形度等进行了测量和分析。结果表明:在无氧环境下,通过450~900℃的高温热解及致密化可将在聚α甲基苯乙烯芯轴上沉积的掺硅碳氢聚合物涂层转变成致密的SiC微球。SiC微球呈非晶态,其C/Si原子比约为1.3,主要含有C—Si键和C=C键,微观结构呈无规则状且颗粒分布均匀,密度、球形度和壁厚均匀性分别为2.62 g/cm~3、99.8%和96.8%。     

Surface Decontamination of Chemical Agent Surrogates Using an Atmospheric Pressure Air Flow Plasma Jet

An atmospheric pressure dielectric barrier discharge (DBD) plasma jet generator using air flow as the feedstock gas was applied to decontaminate the chemical agent surrogates on the surface of aluminum, stainless steel or iron plate painted with alkyd or PVC. The experimental results of material decontamination show that the residual chemical agent on the material is lower than the permissible value of the National Military Standard of China. In order to test the corrosion effect of the plasma jet on different material surfaces in the decontamination process, corrosion tests for the materials of polymethyl methacrylate, neoprene, polyvinyl chloride (PVC), polyethylene (PE), phenolic resin, iron plate painted with alkyd, stainless steel, aluminum, etc. were carried out, and relevant parameters were examined, including etiolation index, chromatism, loss of gloss, corrosion form, etc. The results show that the plasma jet is slightly corrosive for part of the materials, but their performances are not affected. A portable calculator, computer display, mainboard, circuit board of radiogram, and a hygrometer could work normally after being treated by the plasma jet.     

铀酰在氧化石墨烯和碳纳米纤维上吸附的研究进展

铀是核能利用过程中（包括铀矿开采加工、乏燃料后处理和放射性废物的处置等）存在的重要元素之一。铀酰(UO²⁺₂)具有很好的水溶性易于在环境中扩散、迁移与转化。由于其放射性和化学毒性，铀酰进入环境中将对生物和人类造成潜在的威胁。因此，开发新型的纳米材料对水中铀酰的治理具有非常重要的意义。本论文评述氧化石墨烯(GO)、碳纳米纤维(CNF)及其复合材料对铀酰的吸附过程，为实际含铀废水的治理提供理论依据，为我国核能可持续发展和核环境的保护提供技术支持。