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排序方式: 共有901条查询结果,搜索用时 359 毫秒
181.
J. Comyn A.J. Kinloch C.C. Horley R.R. Mallik D.P. Oxley R.G. Pritchard S. Reynolds C.R. Werrett 《International Journal of Adhesion and Adhesives》1985,5(2):59-65
Inelastic electron tunnelling spectroscopy is a way of obtaining the vibrational spectra of molecules adsorbed on a metal oxide. Hence it is appropriate to use this technique to examine adhesives and adhesion promoters. Here, the principles and methods of inelastic electron tunnelling spectroscopy are presented, with the results of studies on polyvinylacetate, polymethylmethacrylate and some silane adhesion promoters. 相似文献
182.
用红外光谱法和热重分析法定性和定量分析研究复配型防老剂,通过试验确定了试验方法,应用这一方法可以了解和掌握复配型防老剂的重量稳定性。 相似文献
183.
在有氧和无氧气氛条件下,采用真空电子束热蒸发技术在P-Si(100)硅衬底上制备了HfO2薄膜.利用X射线光电子能谱,对薄膜的化学组分进行表 征,利用椭偏法对薄膜的膜厚和折射率进行测定,利用紫外可见光谱测量了薄膜的在200 nm~1 200 nm范围内的光透过率,并计算出其光学能隙,利用C-V测试系统对退火后薄膜的介电性能进行测试.结果表明,有氧和无氧条件下制备的薄膜中组分含量存在明显差异,相比于无氧条件下制备的薄膜,有氧条件下制备的薄膜中含有较少的铪单质,因而在可见光范围内具有较高透光率和光学能隙,较低的折射率和更优异的介电性能. 相似文献
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Lipase has been immobilized onto different films, polypropylene and poly(tetrafluoroethylene‐perfluroro‐propyl vinyl ether) using glutalaradehyde as a crosslinker. Differential scanning calorimetery, Fourier transform infrared spectroscopic, x‐ray diffraction, and scanning electron microscopy measurements were carried out to confirm the structure of the polymer films as well as the immobilization process of the enzyme onto the polymeric carrier. The activity and stability of the resulting biopolymers produced by lipase have been compared to those for the native lipase. The experimental results showed that the optimum temperature and pH were 40°C and 8.0, respectively. The activity of the immobilized lipases varied with lipase concentration and with the yield of grafting. Subjecting the immobilized enzymes to a dose of γ‐radiation of (0.5–10 Mrad) showed complete loss in the activity of the free enzyme at a dose of 5 Mrad. A leakage of the enzyme from the irradiated membranes was not observed in the repeated batch enzyme reactions. The operational stability of the free and immobilized lipase in n‐hexane showed that the immobilized enzyme was much more stable than the free one. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 155–167, 2003 相似文献
186.
N. Cella H. El Rhaleb J.P. Roger D. Fournier E. Anger A. Gicquel 《Diamond and Related Materials》1996,5(12):1424-1432
Micron thick diamond films have been studied by spectroscopic ellipsometry (SE). The films were grown, on previously prepared Si(100) substrates, by the plasma enhanced chemical vapor deposition (PECVD) technique. Ex situ SE measurements were carried out on samples grown under different conditions, such as substrate temperature and methane fraction in the gas mixture. An optical model consisting of five layers was constructed in order to explain the SE spectra and to provide the optical and structural parameters of the films. This model was deduced from results of various measurements performed by other characterization techniques (Raman spectroscopy, scanning electron microscopy, atomic force microscopy and positron annihilation spectroscopy) which have revealed the optical and structural parameters of the samples. Its sensitivity to the surface and interface roughness as well as to the absorption of the nondiamond phase of the film is demonstrated. Several values of the percentage of the nondiamond phase can be obtained, with the same fit quality, however, depending on the amorphous carbon reference used in the model. These references were obtained by performing SE measurements on various amorphous carbon films. Finally, our SE analysis has allowed us to monitor the lateral homogeneity of the thickness, surface and interface roughness and nondiamond phase concentration over the diamond film. 相似文献
187.
Kavita Srivastava Manoj Kumar Kaushik Deepak Srivastava Santosh Kumar Tripathi 《应用聚合物科学杂志》2006,102(5):4171-4176
Resoles were prepared separately with different phenols, with formaldehyde having phenol‐to‐formaldehyde mole ratio of 1:2 in basic medium at 70°C. These resoles were physically blended with different weight percentages of diglycidyl ether of bisphenol‐A (DGEBA)–epoxy resin. The blends were cured with 40, 50, and 60 wt % polyamide (based on total amount of the blended resin). Decomposition kinetics of blend sample was studied by dynamic thermogravimetric (TG) analysis. It was found that the degradation of most of the blend samples followed two‐step second‐order degradation kinetics with 50 wt % polyamide and varied reaction orders with 40 and 60 wt % polyamide and type of phenols used in the resole. The energy of activation (E) was found to be maximum with the blend system containing p‐cresolic resole and epoxy. The value of preexponential factor (Z) decreased when phenolic resole was changed to p‐cresolic resole in the blend. Also, the plotted values of E and Z were found to be in close resemblance with those obtained from calculated values. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:4171–4176, 2006 相似文献
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小型近红外玉米蛋白质成分分析 仪器设计的波段选择 总被引:4,自引:2,他引:4
采用傅里叶变换近红外漫反射光谱技术和偏最小二乘法(PLS)建立了玉米蛋白质含量的定标模型。按照预测效果优选光谱波段,为设计小型近红外玉米蛋白质成分分析仪器提供依据。采用多元散射校正方法对光谱进行预处理,然后利用Savitzky-Golay平滑法对原谱、一阶导数谱和二阶导数谱进行平滑处理。选取全谱、合频、一倍频、二倍频和蛋白质基团等5个波段,每个波段分别采用原光谱、一阶导数谱、二阶导数谱,共建立15个定标模型。同时调整Savitzky-Golay平滑点数和PLS因子数,通过多次PLS数值实验比较,按照预测效果确定每个模型的最优平滑点数、因子数,再从中选优。结果表明,采用一阶导数谱的一倍频波段(7 000~5 500 cm-1)的定标效果最好,模型的预测相关系数、预测均方根偏差、相对预测均方根偏差分别为0.945,0.357,3.340%。一倍频波段可以代替全谱波段并得到更好的定标效果。 相似文献