利用甲烷/氢微波等离子体CVD工艺在纯钛基底上沉积纳米金刚石薄膜

与微米金刚石薄膜不同，纳米金刚石薄膜表面平滑。因此，在摩擦学应用领域中，纳米金刚石薄膜是最理想的。表研究利用CH4／H2微波等离子体CVD工艺在纯钛上沉积出纳米金刚石薄膜和微米金刚石薄膜。采用的沉积条件为：沉积温度约为1173K；沉积压力为8．0kPa；CH4浓度在0．5mol％和5mol％之间变化；沉积时间则从4h到12h不等。金刚石薄膜表面用扫描电镜（SEM）观察。在激光拉曼光谱中，微米金刚石薄膜在1332cm^-1处有sp^3键碳的锐峰。1140cm^-1附近的光谱带与纳米金刚石薄膜的特征有关。并用X射线衍射对金刚石薄膜进行了分析。X射线衍射花样证实，纳米金刚石薄膜存在（111）面和（220）面。金刚石薄膜的表面粗糙度随着CH4浓度的增加而减小。但是，甲烷浓度在2mol％与5mol％之间变化时，金刚石薄膜的表面粗糙度接近50nm。据证实，CH4浓度在2mol％和5mol％之间，利用CH4／H2微波等离子体CVD工艺可以沉积出纳米金刚石薄膜。     

Mimicking Nanometer Atomic Processes on a Micrometer Scale via Electrophoretic Deposition

The process of submonolayer formation during the electrophoretic deposition (EPD) of colloidal films of micrometer-sized (diameter ∼ 0.5 μm) silica particles on a silicon wafer has been observed as a function of deposition time. The process of nucleation and growth of the silica monolayer is compared with that of atomic film growth (10000 times smaller scale) via molecular-beam epitaxy (MBE), and for the first time, a striking similarity between the two growth processes is observed. Likewise in the atomic growth process via MBE, the entire nucleation, growth, and aggregation process during EPD of silica particles can be broadly classified into two regions. At low surface coverage when silica particles are deposited outside of clusters, diffuse randomly, and stick to a cluster on touching them, the mechanism of growth in this region follows diffusion-limited aggregation (DLA) and the fractal dimension of the two-dimensional clusters is found to be close to 1.65. Later on, as the clusters grow in size, deposition of particles inside the clusters become important and clusters become more and more compact, resulting in a dense, close-packed, and homogeneous monolayer. This region is termed a consolidation region, and a change in fractal dimension from 1.65 toward 2 with increasing surface coverage has been observed.     

聚苯胺/氧化锌复合膜的制备及其防腐性能

将化学氧化法制备的聚苯胺(PANi)粉末溶于氮甲基吡咯烷酮溶剂后涂覆到制备有ZnO底层的碳钢基体上,获得了PANi/ZnO复合膜。通过扫描电镜、X射线衍射、极化曲线、电化学阻抗谱等测试手段分析了PANi/ZnO复合膜的形貌、成分、与基体的粘附力强度及在3.5%NaCl溶液中的耐腐蚀性能。结果表明,在碳钢基体上制备的PANi/ZnO复合膜中的ZnO呈纳米棒状,提高了复合膜的均匀性和表面平整性,增强了复合膜与金属基体的粘附力。与裸碳钢片相比,有复合膜层的试样的开路电位正向偏移180mV左右,自腐蚀电流密度降低。PANi/ZnO复合膜有效提高了碳钢基体的防腐性能。     

纳米ZnO改性聚酯抗凝血性能研究

采用原位聚合方法制备了纳米ZnO/聚酯复合物,采用热压成膜和溶液法成膜两种方法将其制膜,利用动态凝血实验研究了纳米ZnO添加量及成膜方法对聚酯抗凝血性能的影响。结果表明,溶液法成膜的薄膜抗凝血性能优于热压法成膜。含有纳米ZnO的聚酯薄膜的抗凝血性能优于纯聚酯薄膜。随着纳米ZnO的加入量不断增加,聚酯薄膜的抗凝血性能先增加后减少。     

CVD金刚石膜投资财务分析

文章从经济的角度,通过专业的财务分析,对CVD金刚石膜这一新型材料的投资价值进行研究。研究认为,CVD金刚石膜将成为金刚石材料未来发展的主流,其材料和制品具有广阔的市场前景。因此,投资CVD金刚石膜将获得丰厚的经济回报。     

Synthesis of diamond nanocrystals on polyimide film

Sulfur-assisted hot-filament chemical vapor deposition (HFCVD) was recently employed to grow diamond nano-crystals on polyimide film [F. Piazza, G. Morell, Diamond and Related Materials, 16 (2007) 1950], unambiguously showing that the substrate temperature was below 360 °C, the polyimide glass transition temperature. This accomplishment has opened the door to employ diamond in a wide range of applications where it needs to be integrated with temperature sensitive materials. The result reported earlier relies on visible Raman spectroscopy analysis. We hereby report new additional evidences confirming the result from transmission electron microscopy (TEM), high-resolution TEM, energy dispersive X-ray analysis, electron energy loss spectroscopy and selected area electron diffraction.     

Precursors of copper/zinc oxide catalysts

Recent results on hydroxycarbonate precursors of copper/zinc oxide catalysts for methanol synthesis are reinterpreted, taking into account earlier work on these systems. This revised version was published online in July 2006 with corrections to the Cover Date.     

Computer-simulated diamond/graphite structure based on the diffraction pattern

Theoretical diffraction patterns have been computed with the use of a known spatial structure of a spherical two-phase nanocrystal particle consisting of a diamond core and an outer graphite shell. This approach not only allowed direct determination of the structure of nanosized crystals but also revealed more exactly its minor details, namely, the effect of the interface (distances between outer diamond core atoms and inner graphite shell atoms) on the diffraction of two-phase nanoparticles.     

纳米氧化锌对天然胶乳膜干燥及硫化性能影响研究

采用失重法和溶胀法研究了普通氧化锌和纳米氧化锌活化的天然胶乳膜的干燥动力学,以及干燥过程中胶乳膜交联密度变化.结果表明:天然胶乳厚胶膜在成膜后仍含有大量水分并且去除困难.纳米氧化锌活化胶膜的干燥速率明显高于普通氧化锌胶膜.干燥温度对干燥过程影响显著,干燥时间随干燥温度升高明显降低.随着干燥的进行,2种氧化锌活化的胶乳膜的交联密度均迅速上升,在相同条件下,纳米氧化锌活化胶乳膜交联密度均比普通氧化锌的大.纳米氧化锌对天然胶乳膜的干燥及硫化过程均有促进作用.     

一种用初级氧化锌粉制备活性氧化锌工艺

研究了硫酸浸出初级氧化锌粉末制备活性氧化锌的工艺，讨论了浸出过程中液固质量比、硫酸质量分数对浸出率的影响。在硫酸锌溶液净化中，选择过硫酸铵除铁的方法。确定了活性氧化锌制备工艺参数，采用廉价的碳酸氢铵作为锌的沉淀剂制备前驱体，选择600℃煅烧前驱体4h。采用透射电镜和X衍射对产物活性氧化锌进行了表征。结果表明：活性氧化锌的粒度分布均匀，形貌为近似球形，其平均粒径为80nm，产品纯度高。采用化学法分析产物，其氧化锌质量分数为99．18％。