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周期换向脉冲电沉积纳米Al_2O_3-Ni复合镀层的摩擦磨损性能 被引量:1
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作者 石淑云 常立民 《电镀与环保》 CAS CSCD 2007年第2期1-3,共3页
直流、周期换向脉冲纳米复合镀层在WM-2005-1型摩擦磨损试验机上,考察其摩擦磨损性能。采用扫描电镜观察镀层及磨损表面形貌,分析磨损机理。结果表明,周期换向脉冲复合镀层的形貌、耐磨性能优于直流复合镀层;载荷和转速对两种复合镀层... 直流、周期换向脉冲纳米复合镀层在WM-2005-1型摩擦磨损试验机上,考察其摩擦磨损性能。采用扫描电镜观察镀层及磨损表面形貌,分析磨损机理。结果表明,周期换向脉冲复合镀层的形貌、耐磨性能优于直流复合镀层;载荷和转速对两种复合镀层的摩擦磨损性能有很大影响。 展开更多
关键词 周期换向脉冲 纳米AAl2O3-ni复合镀层 摩擦磨损性能
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无光条件下天然叶绿素的催化加氢反应 被引量:2
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作者 范崇正 李正华 +2 位作者 焦健 周贵恩 吴缨 《中国科学技术大学学报》 CAS CSCD 北大核心 2000年第6期744-747,共4页
It is found that the natural chlorophyll can carry out hydrogenation reaction by the Ni cluster catalyst at normal temperature (10℃±2℃) and normal pressure in the dark. Along with the reaction going on, the fre... It is found that the natural chlorophyll can carry out hydrogenation reaction by the Ni cluster catalyst at normal temperature (10℃±2℃) and normal pressure in the dark. Along with the reaction going on, the fresh green color of chlorophyll fades gradually and become colorless in the end. Methods of Ultra violet spectrum, High effect liquid chromatogram, Gas chromatogram on line and X ray diffraction are employed to detect the reactants and the products. After reaction, the original chlorophyll A and chlorophyll B disappear; while some small molecules are found, such as CH 4, NH 3, KMgH 3. The reagents chlorophyll and hematoporphyrin are used as standerd references. The TEM image shows the catalyst particle size is within 3 nm~5 nm in the diameter. It is clear that after catalytic hydrogenation, both the porphyrin cycle and the pyrrole structure are broken. Perhaps the reaction imitates the natural decomposition of chlorophyll under reducing conditions (for example, under the deep sea) in nature. In the deep sea there are high pressure, small organic molecules, and very hot fluid with nm metal coming out of the bottom. From the view point of thermodynamics, it is possible to carry out a reverse reaction of the one mentioned above; and seen in this respective, life could have come from the sea. In fact, the porphyrin cycle is stable in natural environment in the Et OH solution of chlorophyll remained for one year, and in the Et OH solution of dead leaves. It can be found intact in both and it can still carry out similar catalytic reactions. Further experiments are conducted by using pyrrole and tetra hydrogen pyrrole as the reactants to carry out catalytic hydrogenation, and the results show that at normal temperature and pressure the pyrrole cycles are also broken and small molecule gases such as CH 4, C 3H 6, C 4H 10 , C 4H 8 are formed. 展开更多
关键词 天然叶绿素 纳米镍 催化加氢 卟啉环 无光
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类镍氪32.8nm激光系统的增益特性理论研究
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作者 赵永蓬 江水森 +3 位作者 丁宇洁 李连波 崔怀愈 姜杉 《中国激光》 EI CAS CSCD 北大核心 2014年第7期11-15,共5页
为了研究类镍氪32.8nm激光输出所需的等离子体状态,利用Cowan程序计算了类镍氪32.8nm激光系统的有关原子参数。根据能级参数,建立并求解了准稳态近似下的有关能级速率方程,计算获得了激光上、下能级的相对粒子数密度和相对增益系数随电... 为了研究类镍氪32.8nm激光输出所需的等离子体状态,利用Cowan程序计算了类镍氪32.8nm激光系统的有关原子参数。根据能级参数,建立并求解了准稳态近似下的有关能级速率方程,计算获得了激光上、下能级的相对粒子数密度和相对增益系数随电子温度和电子密度的变化规律,并分析了3d94p、3d94d和3d94f组态的能级对激光产生的影响。通过理论计算得到实现类镍氪32.8nm激光输出所需的最佳等离子体状态。最佳电子温度约为75eV,最佳电子密度约为1018 cm-3。计算结果为未来开展毛细管放电抽运类镍氪32.8nm激光实验提供了理论依据。 展开更多
关键词 原子与分子物理学 类镍氪 软X射线激光 32.8nm 相对增益系数 电子密度 电子温度
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