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21.
Fernando J. Beltrán 《臭氧:科学与工程》1997,19(1):13-38
Kinetics of competition between the ozone direct reaction with compounds in water, ozone-hydroperoxide ion reaction leading to free radicals in the O3/H2O2 process, and the photolysis of ozone in the O3/UV process are discussed in terms of diffusion and reaction times to establish conditions for these reactions to be competitive. Film theory and chemical kinetic concepts then are applied to estimate initial rates of ozone absorption and consumption, removal rates of compounds present in water, and the importance of the radical oxidation path versus direct ozone and/or photolysis reactions. 相似文献
22.
Composite membranes were prepared by grafting plasma-polymerized films onto the surface of nonporous poly (dimethylsiloxane)
films. Gas permeabilities of the composite membranes were measured at 35°C, 1 atm for N2, 02, CO2 and CH4. The permeation properties of the composite membrane was analyzed using the series resistance model. There was a great interfacial
resistance to CH4 permeation through the composite membrane. The interfacial resistance was negligible for the other gases. The interfacial
resistance seems to be a result of an interfacial layer caused by the interaction between the bulk two layers. For CH4 gas, the permeation rate through the composite membrane was affected by the direction of flow. The directional dependence
was negligible for the other gases. 相似文献
23.
The evaporative heat transfer of the non-boiling annular two-phase flow of air-water in a small vertical tube with uniform wall heat flux was studied both theoretically and experimentally. A simplified two-phase flow boundary layer model was used to calculate the thickness of the water film attached to the wall, and from the liquid film thickness the evaporative heat transfer coefficients of the annular two-phase flow were obtained. Theoretical equations and semi-theoretical equations were proposed for predicting the evaporative heat transfer of the annular two-phase flow of air-water in a small vertical tube. The semi-theoretical prediction agrees well with the experimental data. The mechanism of the heat transfer enhancement is the evaporation of the thin liquid film attached on the wall. 相似文献
24.
Hyun Jin Chung Suk Jin Chung Min Ku Jeon Seong Ihl Woo 《Korean Journal of Chemical Engineering》2006,23(2):329-332
The ((Bi3.5La0.5)Ti3O12(BLT) thin-films used in this study were fabricated on a Pt(111)/SiO2/Si(100) substrate by a Liquid Source Misted Chemical Deposition (LSMCD) technique. X-ray diffraction patterns showed that
the BLT films were crystallized and no other phases were observed when annealed above 650 ‡C. Grain size and remnant polarizations
increased with increase in the annealing temperature, while leakage current densities decreased. The remnant polarizations
(Pr) increased from 2.0 to 4.8 and 19.0 μC/cm2 with increase in the annealing temperature from 650 to 700 and 750 ‡C, respectively.
The BLT films annealed at 700 ‡C in O2 showed a good fatigue resistance of reduced polarization by 10% after 109 switching cycles when 9 V of bipolar voltage was applied at a frequency of 40 kHz. 相似文献
25.
不锈钢在湿法磷酸中腐蚀行为研究 总被引:2,自引:0,他引:2
本文采用腐蚀实验和电化学测试方法对不锈钢在湿法磷酸中的腐蚀行为进行了研究,并进行钝化膜的组成与结构分析。研究表明,磷酸中加入SO4^2^-,cL^-,F^-均提高合金的维钝电流密度和致纯电流浓度,加速材料的腐蚀,这些杂质共存时腐蚀性更大。湿法磷酸中存在的Si^4^+,Al^3^+,Mg^2^+和Fe^3^+起缓蚀作用。不锈钢纯化膜主要由Cr和Fe的氧化物组成,表面形成致密稳定的Cr2O3保护膜是提 相似文献
26.
虞继平 《网络安全技术与应用》2014,(3):209-209,212
随着电影行业的不断发展,数字3D立体电影的应用日益广泛。本文从立体电影的原理出发,在对传统立体电影的应用技术进行了阐述后,着重分析了现今电影行业应用最为广泛的几种数字3D电影应用技术,集中探讨了不同放映技术的工作原理及其优缺点。最后就数字3D技术的发展前景进行了探讨,为数字3D电影的长远发展提供理论支持。 相似文献
27.
Jae-Wook Lee Kyung-June Hwang Wang-Geun Shim Kyung-Hee Park Hal-Bon Gu Kyu-Hyuk Kwun 《Korean Journal of Chemical Engineering》2007,24(5):847-850
Dye sensitized solar cells (DSSCs) have been receiving significant attention because they have many advantages compared to
conventional organic solar cells. It has been known that the photovoltaic characteristics of DSSC are highly dependent on
the adsorption properties of dyes on TiO2 films. To analyze the surface heterogeneity of TiO2 surfaces, single-phase anatase nanocrystallite titanium films were prepared by sol-gel method using the hydrolysis reaction
of titanium tetraisopropoxide under acidic condition and characterized by XRD, FE-SEM and BET analysis. The adsorption energy
distribution functions were calculated by the generalized nonlinear regularization method. It was found that the shape and
the intensity of the adsorption energy distribution curve determined were highly related with the physical properties (i.e.,
geometrical heterogeneity) and chemical characteristics (i.e., energetic heterogeneity) of nanocrystalline TiO2 for DSSC. 相似文献
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30.
比较了JB/T 4730-2005《承压设备无损检测》和SY/T 4109-2005《石油天然气钢质管道无损检测》两个标准射线部分的不同之处,包括射线源和能量的选择、透照次数、底片质量和质量分级等方面,便于无损检测工作者更好地理解标准和准确地使用标准,从而保证无损检测工作质量和工程焊接质量。 相似文献