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131.
Hyung Mi Lim Yonghwa Lee Seung-Ho Lee Chultack Lim Dae Sung Kim 《Research on Chemical Intermediates》2012,38(6):1203-1213
Barium carbonate (BaCO3) particles have been obtained by the precipitation reaction of CO2 bubbles to barium hydroxide [Ba(OH)2] in the ethanol–water mixed solvents. Various morphologies, from rounded peanut, leaf-like, rod, and needle particles, were
controlled by the precipitation step, where CO2 gas was fed to Ba(OH)2 in ethanol–water mixed solvent. The CO2 gas as a carbonate source and Ba(OH)2 slurry as a barium ion source are dissolved in the mixed solvents, within the solubility limit, to precipitate. The reactants
dissolve progressively while they precipitate to BaCO3. Ba(OH) 2 slurry becomes translucent and opaque while the reaction proceeds. It becomes more opaque, upon which the dissolution of
Ba(OH)2 proceeds and BaCO3 precipitates. The opaqueness of the products depends on the particle size of BaCO3 in the product. The characteristics of BaCO3 were confirmed by the X-ray diffraction (XRD), transmission electron microscope (TEM), and electrophoretic light scattering
methods. The amount of water in the mixed solvents and of Ba(OH) 2 in the reaction batch is related to the reaction rate in the nucleation and growing step, so that it was possible to control
the shape of particles. Based on the understanding of the size and morphology of BaCO3 in the solid/liquid–gas system, it was possible to obtain a well-dispersed average 40-nm BaCO3 colloid. 相似文献
132.
133.
D. Gopi R. Saraswathy G. Athithya L. Kavitha Jeong‐Heo Bae Dae–Kyeong Kim 《Surface and interface analysis : SIA》2012,44(10):1331-1337
In this paper, we have reported the anti‐corrosion performance of ceria / poly (indole‐co‐pyrrole) (Ce/(poly(In‐co‐Py)) bilayer coating on low nickel stainless steel (LN SS). Electrochemical polymerization of (poly (In‐co‐Py)) was achieved on ceria‐coated LN SS (CeO2/LN SS) in acetonitrile medium containing LiClO4 (ACN‐LiClO4) by cyclic voltammetric technique. The coatings were characterized by analytical techniques like Fourier transform infrared spectroscopy, scanning electron microscopy with energy dispersive analysis of X‐ray, respectively. The mechanical behavior of the coatings was studied using peel test, hardness and wear resistance tests. The corrosion defensive performance of this bilayer coating on LN SS was investigated using electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy in 0.5 M H2SO4. These results show that the bilayer coating on LN SS lowered the permeability of corrosive ions present in the acidic medium and thus acts as a barrier against the attack of corrosive environment. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
134.
Sung‐Young Park Hee‐Young Park Hwa‐Soo Lee Sang‐Wook Park Chang‐Sik Ha Dae‐Won Park 《Journal of polymer science. Part A, Polymer chemistry》2001,39(9):1472-1480
This study was related to the investigation of the chemical fixation of carbon dioxide to a copolymer bearing epoxide and the application of the cyclic carbonate group containing copolymer‐to‐polymer blends. In the synthesis of poly[(2‐oxo‐1,3‐dioxolane‐4‐yl) methyl methacrylate‐co‐ethyl acrylate] [poly(DOMA‐co‐EA)] from poly(glycidyl methacrylate‐co‐ethyl acrylate) [poly(GMA‐co‐EA)] and CO2, quaternary ammonium salts showed good catalytic activity. The films of poly(DOMA‐co‐EA) with poly(methyl methacrylate) (PMMA) or poly(vinyl chloride) (PVC) blends were cast from N,N′‐dimethylformamide solution. The miscibility of the blends of poly(DOMA‐co‐EA) with PMMA or PVC have been investigated both by DSC and visual inspection of the blends. The optical clarity test and DSC analysis showed that poly(DOMA‐co‐EA) containing blends were miscible over the whole composition range. The miscibility behaviors were discussed in terms of Fourier transform infrared spectra and interaction parameters based on the binary interaction model. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1472–1480, 2001 相似文献
135.
Kye Chun Nam Seung Whan Ko Sung Ok Kang Seung Hyun Lee Dae Soon Kim 《Journal of inclusion phenomena and macrocyclic chemistry》2001,40(4):285-289
Several quadruply bridged calix[6]arenes were prepared in high yield by the reaction of various 1,4-di-O-alkylated calix[6]arenes with 1,2,4,5-tetrakis-(bromomethyl)benzene in the presence of Cs2CO3. The alkali metal extraction study established that this compound shows the high selectivity toward Cs+ among alkali metal cations. The cesium binding characteristics were investigated with 1H NMR and UV spectroscopy. 相似文献
136.
Recently, ozone concentrations have increased dramatically as a result of vehicle usage in metropolitan areas. Ozone precursors are composed of hydrocarbons of organic compounds. Because hydrocarbons are indicative of ozone formation, they need to be monitored in ambient air. Since ozone precursor are present at very low levels (from ppb to ppt) in ambient air, they are difficult to analyze accurately. This study investigates ozone precursors in ambient air. The main purpose of this study is to compare analytical methods for the measurement of ozone precursors in atmosphere. Two measurement methods were evaluated using canister (Silco-canister) and adsorbent (300-mg Carbopack B+150-mg Carbosieve SIII) tube. Differences in measurements for total ozone precursor emissions were 54.1% between the adsorption tube and canister-GC/MS, 51.1% between adsorption tube and canister-GC/FID, and 16.3% between canister-GC/MS and canister-GC/FID. 相似文献
137.
In this study, we introduce outdoor sound simulation that is fully compliant with ISO 9613 yet with some complementary methods that enhance its applicability; for example, calculation of sound attenuation due to undulating terrain in octave bands, geometric divergence in the near-field of the source, and short-term wind effects. Using the method, we have carried out highway traffic noise prediction and measurement for 12 sites with representative road shapes and structures. In the prediction, the sound power level for a road segment was estimated by the method suggested in ASJ Model-1998 with experimental corrections to the overall noise level and spectrum. Comparing results between predicted and measured noise levels show good correspondence at direct, diffracted and reflected sound fields within 30m from the center of the near side lane. 相似文献
138.
Phantom Maps from a Strong Homology Viewpoint 总被引:1,自引:0,他引:1
Dae Woong LEE 《数学学报(英文版)》2006,22(3):711-718
Let X and Y be connected nilpotent CW-complexes of finite type. In this paper we deal with another complete analysis of a set of phantom maps in terms of strong homology by using the derived functors. We also prove that the set of homotopy classes of maps is independent of the choice of both rational homotopy equivalent classes and completion genera. 相似文献
139.
We calculate the decay constant ratios ? ηc/? J/ψ and ? ηb/? ψ. In the calculation we take into account the mock meson structures of the mesons, as well as the difference of the wave functions at origin of the vector and pseudoscalar mesons studied by Ahmady and Mendel. We find that the different spin structures of the mesons much affect the ratios. We incorporate our results in the prediction of the branching ratios of B → K η c. 相似文献
140.
The degrees of surface and through cure of UV curable acrylate-based pigmented systems were studied by using ATR(Attenuated Total Reflection) spectroscopy. This paper describes curing investigations of ink coating layer on optical fibers. 相似文献