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61.
Hwack Joo Lee Hyun Ryu Hyun Min Park Jong Hoo Paik Sahn Nahm Jae-Dong Byun 《Journal of the American Ceramic Society》1998,81(6):1685-1688
Microstructural studies on the interfacial boundaries of 1:1 and 1:2 ordered domains in (Ba0.9 La0.1 )(Mg0.37 Nb0.63 )O3 were conducted using high-resolution transmission electron microscopy and X-ray diffractometry. Both 1:2 and 1:1 ordered domains coexisted in a fully ordered single grain. Each ordered domain occupied its own region, and the interfaces were atomically sharp and coherent. The wavelength of the superlattice modulation was ∼0.47 nm in the 1:1 ordered domain and ∼0.71 nm in the 1:2 ordered domain. The transition from the 1:2 ordered region to the 1:1 ordered region was clearly shown at the interface. These observations well support the structural models that have been previously presented. 相似文献
62.
Ki Yeol Byun Isabelle FerainJohn Hayes Ran Yu Farzan Gity Cindy Colinge 《Microelectronic Engineering》2011,88(4):522-525
In this work, an alternative method for producing the single crystalline Ge-Si Avalanche photodiodes (APD) with low thermal budget was investigated. Structural and electrical investigations show that low temperature Ge to Si wafer bonding can be used to achieve successful APD integration. Based on the surface chemistry of the Ge layer, the buried interfaces were investigated using high resolution transmission electron microscopy as a function of surface activation after low temperature annealing at 200 and 300 °C. The hetero-interface was characterized by measuring forward and reverse currents. 相似文献
63.
Eight representative types of juk (Korean traditional congee) cooked with seafood, and plain juk were analyzed for biogenic amine content. Results revealed that while plain juk contains no biogenic amines, juk prepared with seafood has a high level of histamine, ranging from 120 to 170 mg/kg. The seafood used in juk preparation contained different concentrations of histamine, ranging from 60 to 300 mg/kg. No other biogenic amines were detected in most juk and seafood samples. The bacterial contribution to the biogenic amine content in selected seafood was evaluated by analyzing the bacterial distribution and ability to produce biogenic amines. Strains of Achromobacter, Staphylococcus, and Micrococcus that are capable of producing biogenic amines are the dominant genera in the seafood tested. Therefore, this study suggests that the levels of dominant bacteria need to be controlled to reduce the amounts of biogenic amines in seafood and, thereby, in juk prepared with seafood. 相似文献
64.
Mun Ho Kim Doo-Jin Byun Ji-Eun You Kil-Yeong Choi 《Journal of Industrial and Engineering Chemistry》2013,19(3):920-925
The white-colored inner surface of a polypropylene (PP) material containing water discolored and turned yellow. The discoloration occurred selectively on the surface at the point of contact with the air–water interface. Since the polymer surface was exposed to water in darkness at room temperature, no sign of deterioration or degradation of the polymer at the discolored surface was confirmed. This study conducts an in-depth analysis of the discoloration mechanism of the polymer surface. A variety of technical approaches, including microscopic, spectroscopic, and chromatographic analysis techniques, were used to investigate the nature of discoloration and the root cause. From the analysis results, the discoloration was ascribed principally to a phenol transformation compound having the structure of a quinone methide, which was identified as a degradation product of a primary antioxidant. Based on the observations and experimental results, a plausible discoloration mechanism was proposed. 相似文献
65.
Effect of Na-diffusion on the electrical properties of SrTiO3 总被引:3,自引:0,他引:3
Grain boundary characteristics of Na-diffused SrTiO3 were investigated. It was observed that Na ions are segregated in grain boundaries by secondary ion mass spectroscopy analysis. Using I-V characteristics and C-V measurement, the non-linearity coefficient and the potential barrier height were found to be 15.6, 0.82 eV, respectively. The I-V characteristics, complex plane analysis, and dc voltage step technique were performed to study the electrical properties of a single grain boundary. From the results of complex plane analysis, the deep electronic level was varied from 0.10 to 0.31 eV, which can be explained by the substitution of Na ions for Sr ions. 相似文献
66.
Hyun-Joo Ahn Jae-Hyun Kim Cheorun Jo Hong-Sun Yook Hyun-Ja Lee Myung-Woo Byun 《Food Control》2003,14(8):553-557
Salted and fermented anchovy sauce spiked with or without N-nitrosodimethylamine (NDMA) and N-nitrosopyrrolidine (NPYR) was irradiated at 0, 5, 10, 15 and 20 kGy. NDMA and NPYR reduction by irradiation was not observed in non-spiked samples at 0 week, while a significant reduction was observed after 4 weeks of storage at 15 °C (P<0.05). In N-nitrosamine spiked samples, a positive effect of irradiation on NDMA and NPYR reduction was observed. NDMA and NPYR levels were decreased by irradiation at 5 kGy or above after storage. Therefore, gamma irradiation has a possibility to reduce N-nitrosamines in salted and fermented anchovy sauce. 相似文献
67.
Asymmetric microporous membranes based on polystyrene cross-linked with divinyl benzene were prepared. They were sulfonated with sulfonic acid and washed with solutions of gradually increasing pH to reduce environmental shock. The sulfonation was monitored by infrared spectroscopy, and changes in wettability and sulfur content were also recorded. Morphologies and reverse osmosis performance of sulfonated membranes were measured, with both water flux and salt rejection increasing after treatment. © 1994 John Wiley & Sons, Inc. 相似文献
68.
This study was performed to evaluate the biodegradability of acrylonitrile wastewater, microbial inhibition effect of acrylonitrile wastewater on removal efficiency and the activity of sulphate reducing bacteria (SRB) according to COD/sulphate ratio. Acrylonitrile wastewater was hardly biodegradable in a biodegradability test, however, SRB activity was 57% for overall consumption of electron donor and it was relatively high value compared to 17% of reference test with glucose. COD removal of acrylonitrile wastewater was improved to 57% and 61% from 20% as the COD/sulphate ratio were 0.5 and 0.3 by sulphate addition to acrylonitrile wastewater. First order reaction rate constants k on organic removal of acrylonitrile wastewater were 0.001, 0.004 and 0.004 at each COD/sulphate ratio of 0.9, 0.5 and 0.3. Thus it was suggested that the activity of SRB was a significant factor for removing organics and sulphate simultaneously in acrylonitrile wastewater. 相似文献
69.
Dunn E.A. Jin-Kyu Byun Branch E.D. Jian-Ming Jin 《Antennas and Propagation, IEEE Transactions on》2006,54(3):945-952
Numerical simulations of body-of-revolution geometries for scattering and radiation problems are presented. The formulation consists of a finite element-boundary integral (FE-BI) method which is based on a finite element method that uses higher order nodal-based scalar basis functions for the azimuthal field component and higher order edge-based vector basis functions for the transverse field. This formulation, when combined with a symmetric FE-BI hybridization scheme, yields a final system of equations that is more accurate than earlier first-order formulations. Numerical examples are given to demonstrate the accuracy and capabilities of the higher order solution. 相似文献
70.
Se-Jin Joo Hee-Jung Park Ji-Hae Park Jin-Gyeong Cho Ji-Hyun Kang Tae-Sook Jeong Hee Cheol Kang Dae-Young Lee Hack-Soo Kim Sang-Yo Byun Nam-In Baek 《International journal of molecular sciences》2014,15(9):16418-16429
Stems of Machilus japonica were extracted with 80% aqueous methanol (MeOH) and the concentrated extract was successively extracted with ethyl acetate (EtOAc), normal butanol (n-BuOH), and water. Six flavonoids were isolated from the EtOAc fraction: (+)-taxifolin, afzelin, (−)-epicatechin, 5,3''-di-O-methyl-(−)-epicatechin, 5,7,3''-tri-O-methyl-(−)-epicatechin, and 5,7-di-O-methyl-3'',4''-methylenedioxyflavan-3-ol. The chemical structures were identified using spectroscopic data including NMR, mass spectrometry and infrared spectroscopy. This is the first report of isolation of these six compounds from M. japonica. The compounds were evaluated for their diphenyl picryl hydrazinyl scavenging activity and inhibitory effects on low-density lipoprotein oxidation. Compounds 1 and 3–6 exhibited DPPH antioxidant activity equivalent with that of ascorbic acid, with half maximal inhibitory concentration (IC50) values of 0.16, 0.21, 0.17, 0.15 and 0.07 mM, respectively. The activity of compound 1 was similar to the positive control butylated hydroxytoluene, which had an IC50 value of 1.9 µM, while compounds 3 and 5 showed little activity. Compounds 1, 3, and 5 exhibited LDL antioxidant activity with IC50 values of 2.8, 7.1, and 4.6 µM, respectively. 相似文献