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991.
Namhoon Kim Changkyu Kim Soyoung Jung Youngae Park Youngju Lee Juyeon Jo 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2018,35(7):1238-1246
Food-grade titanium dioxide (TiO2) is a common and widespread food additive in many processed foods, personal care products, and other industrial categories as it boosts the brightness and whiteness of colours. Although it is generally recognised as safe for humans, there is a growing interest in the health risks associated with its oral intake. This study quantified and identified TiO2 nanoparticles present in confectionery foods, which are children’s favourite foods, with inductively coupled plasma optical emission spectrometry (ICP-OES) and transmission electron microscopy (TEM). A reliable digestion method using hot sulphuric acid and a digestion catalyst (K2SO4:CuSO4 = 9:1) was suggested for titanium analysis. Validations of the experimental method were quite acceptable in terms of linearity, recoveries, detection limits, and quantification limits. Of all the 88 analysed foods, TiO2 was detected in 19 products, all except three declared TiO2 in their labelling. The mean TiO2 content of candies, chewing gums, and chocolates were 0.36 mg g?1, 0.04 mg g?1, and 0.81 mg g?1, respectively. Whitish particles isolated from the confectionery foods were confirmed as TiO2 nanoparticles via TEM and energy dispersive X-ray spectroscopy (EDX), in which nanosized particles (<100 nm) were identified. 相似文献
992.
Jaeeun Lee Siwook Park Hwangsun Kim Seong-Jun Park Keunho Lee Mi-Young Kim Phaniraj P. Madakashira Heung Nam Han 《Metals and Materials International》2018,24(4):702-710
Fe–Al–Mn–C alloy systems are low-density austenite-based steels that show excellent mechanical properties. After aging such steels at adequate temperatures for adequate time, nano-scale precipitates such as κ-carbide form, which have profound effects on the mechanical properties. Therefore, it is important to predict the amount and size of the generated κ-carbide precipitates in order to control the mechanical properties of low-density steels. In this study, the microstructure and mechanical properties of aged low-density austenitic steel were characterized. Thermo-kinetic simulations of the aging process were used to predict the size and phase fraction of κ-carbide after different aging periods, and these results were validated by comparison with experimental data derived from dark-field transmission electron microscopy images. Based on these results, models for precipitation strengthening based on different mechanisms were assessed. The measured increase in the strength of aged specimens was compared with that calculated from the models to determine the exact precipitation strengthening mechanism. 相似文献
993.
Chi-Yeong Ahn Wonchan Hwang Hyunjoon Lee Sungjun Kim Ji Eun Park Ok-Hee Kim Min Her Yong-Hun Cho Yung-Eun Sung 《International Journal of Hydrogen Energy》2018,43(21):10070-10081
An ideal oxygen reduction catalyst for use in fuel cells should exhibit both long-term durability and high activity. In this study, to increase the durability of highly loaded platinum- and platinum-nickel alloy catalysts possessing different types of carbon supports, a nitrogen-doped carbon shell was introduced on the catalyst surface through dopamine coating. As the catalyst surfaces were altered following shell formation, the ionomer contents of the catalyst inks were adjusted to optimise the three-phase boundary formation. Single cell tests were then conducted on these inks by applying them in a membrane electrolyte assembly. Furthermore, to confirm the durability of the catalysts under accelerated conditions, the operation was continued for 200 h at 70 °C and at a relative humidity of 100%. Transmission electron microscopy and electrochemical analysis were conducted before and after the durability tests, and the observed phenomena were discussed for catalysts bearing different types of carbon supports. 相似文献
994.
995.
DaeKil Park 《Quantum Information Processing》2018,17(6):147
The dynamics of entanglement and uncertainty relation is explored by solving the time-dependent Schrödinger equation for coupled harmonic oscillator system analytically when the angular frequencies and coupling constant are arbitrarily time dependent. We derive the spectral and Schmidt decompositions for vacuum solution. Using the decompositions, we derive the analytical expressions for von Neumann and Rényi entropies. Making use of Wigner distribution function defined in phase space, we derive the time dependence of position–momentum uncertainty relations. To show the dynamics of entanglement and uncertainty relation graphically, we introduce two toy models and one realistic quenched model. While the dynamics can be conjectured by simple consideration in the toy models, the dynamics in the realistic quenched model is somewhat different from that in the toy models. In particular, the dynamics of entanglement exhibits similar pattern to dynamics of uncertainty parameter in the realistic quenched model. 相似文献
996.
Nitrogen passivation formation on Cu surface by Ar–N2 plasma for Cu-to-Cu wafer stacking application
Microsystem Technologies - Wafer stacking technology provides reduced interconnect delay, improved bandwidth, reduced form factor, and decreased cost. Solder-based metallic die bonding is presently... 相似文献
997.
The Journal of Supercomputing - With the emergence of the big data era, various technologies have been proposed to cope with the exascale of data. For a considerably large volume of data, a single... 相似文献
998.
999.
Shin Nina Kim Donghui Park Sangwook Oh Jungsuk 《Information Systems and E-Business Management》2018,16(1):125-154
Information Systems and e-Business Management - Mobile commerce, or m-commerce, has quickly become a powerful, indispensable approach for diverse business to consumer (B2C) industries to secure... 相似文献
1000.
Recent observations at operating plants and subsequent US NRC requirements have identified flow stratification in surge lines as a phenomenon that must be considered in the design basis of surge lines. To address these concerns, the stratified loading conditions were included in the design of YGN 3 and 4 surge line as a design basis transient and pipe temperature and displacement measurement were taken during YGN 3 pre-core hot functional testing to determine the degree of surge line flow stratification. The measured displacements and temperatures were extensively reviewed and evaluated in detail: (1) to verify the validity of the thermal hydraulic model used to predict the pipe top-to-bottom temperature differentials; (2) to analytically correlate measured surge line temperatures and displacements; and (3) to confirm the validity of the stratified flow analysis procedure. This paper shows that the stratified flow phenomenon is generic and therefore generic loadings can be developed and evaluated for the surge line analyses. 相似文献