共查询到19条相似文献,搜索用时 62 毫秒
1.
2.
3.
4.
5.
XPS法测量铝箔表面氧化铝的厚度 总被引:2,自引:0,他引:2
介绍了一种无需溅射、无需变角,只需一次简单的XPS(X射线光电子能谱)窄扫描,即可根据谱图中氧化态和金属态的相对强度算出铝金属表面氧化铝的厚度。用该法测量了一系列不同方法处理的铝表面氧比铝厚度,并与椭偏法及NRA法(核反应分析法)测定结果进行了对比,结果表明,该法是一种简便准确的膜厚测量法。 相似文献
6.
采用分子动力学(MD)模拟方法研究了单链聚苯乙烯(PS)在石墨表面的吸附. 模拟结果表明, 吸附后PS在平行于石墨表面的方向可视为准二维椭圆结构, 并且在此方向上的均方回转半径值(R2∥)与其所含单体数目(N)具有指数关系R2∥-N2v, 指数2v约等于1.04; 最后指出PS吸附过程的主要驱动力为PS链段与表面之间的范德华作用力. 相似文献
7.
8.
制作了一组表面具有不同厚度镀铬层的45碳钢标准块,并应用能量色散X荧光光谱法(EDXRF)对镀层厚度进行了测度基数据处理中运用Newton迭代法对工作曲线进行了拟合,结果满意。 相似文献
9.
水在固体表面或在毛细孔玻璃中的性质,一直是人们感兴趣的问题。而靠近固体表面的水,其性质不同于体相(Bulk)水,也是为人所知的事实。已经知道,邻近水的热容、密度、粘度、电导及结构等都不同于体相水。但邻近水的厚度究竟为多少,或者说,这种固体表面对水的性质影响究竟是长程的还是短程的,目前还没有统一的结论。用压汞法测量多孔物质的孔体积,是人们已熟知的方法,但还没有人将其用于测量液体在毛细孔中的体积、密度等行为。我们尝试了用压汞法,测量具有确定孔径的毛细孔玻璃(CPG),在吸附了不同量水后孔体积的变化,进而计算了不同吸附层的水在CPG中的体积、密度。此外还测定了载有不同量正癸烷后,CPG孔体积的变化。 相似文献
10.
超临界甲烷在高表面活性炭上的吸附测量及其理论分析 总被引:22,自引:0,他引:22
实验测定了0~10
MPa,233~333 K (20 K间隔)范围内超临界甲烷在高表面活性炭上的吸/脱附等温线,确定了此物理吸附过程的可逆性,并从实验数据计算出吸附热为16.5
kJ/mol. 建立了描述具有最大点的吸附等温线模型,其总体偏差为±2%. 模型保持了特征吸附能恒定的性质,方程指数亦反映了吸附剂的微孔分布特征,模型参数给出了超临界甲烷的吸附相密度. 将超临界吸附极限态引入等温线模型中,经典的吸附理论亦可解释超临界吸附现象. 相似文献
11.
Summary: It has been demonstrated that diffusion of polycation adsorbed on glass microspheres occurs without desorption of the macromolecules into the solution and, therefore, can be characterizerd as 2D-diffusion. The diffusion coefficint is estimated to be 1.4 × 10−12 cm2/s. 相似文献
12.
Catalyst deposition control is one of the overlooked areas of fuel cell fabrication and research that can affect the overall performance and cost of the fuel cell to manufacture for mass production. The effect of the different individual catalyst layer thicknesses and loadings of the cathode compartment of a direct methanol fuel cell (DMFC) was investigated. The drawdown method was performed at thicknesses varying from 1 mil to 8 mils with platinum loadings ranging from 0.25 mg cm?2 to 2.0 mg cm?2. The membrane electrode assemblies (MEAs) with thicker individual layers (8 mil and 4 mil) performed better overall compared to the ones prepared with thinner individual layers (1 mil). The power density maxima for the different loading levels followed an exponential decrease of platinum utilization at the higher loading levels. The painted MEAs tended to display the similar performance characteristics as the drawdown MEA layers closest to the thickness at the respective loadings. 相似文献
13.
A combined analytical–numerical study is presented for the slow motion of a spherical particle coated with a layer of adsorbed polymers perpendicular to an infinite plane, which can be either a solid wall or a free surface. The Reynolds number is assumed to be vanishingly small, and the thickness of the surface polymer layer is assumed to be much smaller than the particle radius and the spacing between the particle and the plane boundary. A method of matched asymptotic expansions in a small parameter λ incorporated with a boundary collocation technique is used to solve the creeping flow equations inside and outside the adsorbed polymer layer, where λ is the ratio of the characteristic thickness of the polymer layer to the particle radius. The results for the hydrodynamic force exerted on the particle in a resistance problem and for the particle velocity in a mobility problem are expressed in terms of the effective hydrodynamic thickness (L) of the polymer layer, which is accurate to O(λ2). The O(λ) term forLnormalized by its value in the absence of the plane boundary is found to be independent of the polymer segment distribution and the volume fraction of the segments. The O(λ2) term forL, however, is a sensitive function of the polymer segment distribution and the volume fraction of the segments. In general, the boundary effects on the motion of a polymer-coated particle can be quite significant. 相似文献
14.
苯三偶氮衍生物吸附在银溶液上的SERRS谱 总被引:1,自引:0,他引:1
In this paper, the SERRS of BATD has been investigated, the effect of pH, concentration and electrolyte on SERRS was discussed and the adsorbed state of BTAD was figured. We suggest that the adsorbed state of BTAD is the bonding of benzotriazol to Ag surface via lone pair electron on the nitrogen. With HCl and ascorbic acid aggregate Ag sol, the dependence of SERRS on BTAD concentration behaves differently. In the former case, the adsorbed state changes, but in the latter it remains the same. Small amount of electrolyte will induce the active sites on the surface, but when it is more than 1×10-2mol﹒L-1, the competent adsorbtion reduces the Raman scattering intensity. Hydrogen ions protonize BTAD to BTAHD and reduce the contribution of lone pair electron on N atom of the conjugated system. 相似文献
15.
超细氮碳化物中吸附氧和化合氧的测定 总被引:5,自引:0,他引:5
用跟踪式程序升温、红外检测和微机解卷技术,测定氮碳化物超细粉的吸附氧和化合氧,探讨了超细Si3N4,AIN,TiCN和SiC中不同状态氧量与其制备方法,颗粒度及放置时间的关系。 相似文献
16.
17.
采用ITO/PVK/Alq/Al双层电致发光(EL)结构,制备了三种载流子输运层厚度分别为30、 60、 120 nm,发光层厚度均为300 nm的有机薄膜EL器件,测试其EL谱及J-V特性曲线.根据有机EL器件中载流子的产生和输运过程导出了载流子复合几率及电子和空穴密度分布表示式,用以解释其发光强度随输运层厚度的变化关系,用一维无序结构载流子随机跃迁模型讨论输运层厚度对器件电流密度及启动电压的影响,探讨了载流子在薄膜中的输运过程,其理论与实验符合得很好. 相似文献
18.
讨论了原位聚合法制备有机多孔高聚物PLOT柱中毛细管半径r,反应液浓度C及涂层厚度d_s的关系,并通过实验建立了一个计算涂层厚度d_s的经验公式。 相似文献
19.
Hartley Patrick G. Thissen Helmut Vaithianathan Tharshan Griesser Hans J. 《Plasmas and Polymers》2000,5(1):47-60
A method for the determination of coating film thicknesses at nanometer resolution based on surface masking and atomic force microscopy (AFM) is described. A polymeric mask is used to cover part of a substrate during the deposition of thin polymeric coatings by plasma polymerization, allowing the production of well defined polymer steps of heights of a few tens of nanometers. Tapping mode AFM has been employed to analyze the topography of these steps at high resolution. This method has also allowed accurate measurement of the kinetics of the deposition of plasma polymer films over a range of exposure times. XPS analysis of different substrate surfaces following mask removal found barely detectable residues, suggesting that the underlying surface chemistry remains unchanged, and accessible for further modification. In combination with quartz crystal microgravimetry, the method has been applied to the measurement of the density of plasma polymer coatings in the thickness range 4–50 nm. 相似文献