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81.
Young Jae Shin Do Hyeon Yang Mee Hye Oh Yeo Seong Yoon Jae Sup Shin 《Journal of Industrial and Engineering Chemistry》2009,15(2):238-242
Hard coatings were deposited on a polycarbonate plate using a sol–gel process with a melamine derivative, poly(vinyl alcohol) (PVA), and silicates and examined as potential substitutes for glass in cars. PVA was partially functionalized with (3-isocyanatopropyl)triethoxysilane, and the synthesized polymer was used to form a coating solution with methylated poly(melamine-co-formaldehyde), tetraethoxysilane, and methyltriethoxysilane. The coatings that contained both the melamine and silicate structures were deposited using a sol–gel process. The optimum conditions and formulation to obtain excellent physical properties of the coating were determined. Smooth coatings with the hardness of a 3H class pencil, excellent abrasion resistance and transparency were formed. 相似文献
82.
Qiang Wang Ji Hyang Sohn So Ye Park Jin Seong Choi Joo Young Lee Jong Shik Chung 《Journal of Industrial and Engineering Chemistry》2010,16(1):68-73
Pure phase K4Zr5O12 is synthesized via solid state method in the present work. Various K/Zr ratios and temperatures are applied, and the synthesis process is investigated in detail by means of X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. Its catalytic activity for soot oxidation is studied by temperature programmed oxidation with different types of soot/catalyst contacts. It is revealed that K4Zr5O12 is very active in the presence of 2–10% O2 for both tight and loose contacts (Tp(tight) = 335 °C, Tp(ethanol) = 355 °C and Tp(shaking) = 370 °C). Thermal stability study shows that K4Zr5O12 is highly stable up to at least 900 °C. 相似文献
83.
Young Cheol Park Sung-Ho Jo Keun-Woo Park Yeong Seong Park Chang-Keun Yi 《Korean Journal of Chemical Engineering》2009,26(3):874-878
The effect of bed height on CO2 capture was investigated by carbonation/regeneration cyclic operations using a bubbling fluidized bed reactor. We used a
potassium-based solid sorbent, SorbKX35T5 which was manufactured by the Korea Electric Power Research Institute. The sorbent
consists of 35% K2CO3 for absorption and 65% supporters for mechanical strength. We used a fluidized bed reactor with an inner diameter of 0.05
m and a height of 0.8 m which was made of quartz and placed inside of a furnace. The operating temperatures were fixed at
70 °C and 150 °C for carbonation and regeneration, respectively. The carbonation/regeneration cyclic operations were performed
three times at four different L/D (length vs diameter) ratios such as one, two, three, and four. The amount of CO2 captured was the most when L/D ratio was one, while the period of maintaining 100% CO2 removal was the longest as 6 minutes when L/D ratio was three. At each cycle, CO2 sorption capacity (g CO2/g sorbent) was decreased as L/D ratio was increased. The results obtained in this study can be applied to design and operate
a large scale CO2 capture process composed of two fluidized bed reactors.
This work was presented at the 7
th
China-Korea Workshop on Clean Energy Technology held at Taiyuan, Shanxi, China, June 26–28, 2008. 相似文献
84.
Hyun Kyu Jung Chang Hee Kim A-Ra Hong Seung Han Lee Tae Cheol Kim Ho Seong Jang Dong Hun Kim 《Ceramics International》2019,45(8):9846-9851
Functional materials exhibiting magnetic and luminescent properties have been recognized as an emerging class of materials with great potential in advanced applications. Herein, properties of multifunctional ceramic composites consisting of two garnets, luminescent cerium-doped Y3Al5O12 (Ce:YAG) and magnetic Y3Fe5O12 (YIG), are reported. On increasing the sintering temperature, both the photoluminescence and saturation magnetization of the Ce:YAG-YIG composites decreased gradually because of the interdiffusion of trivalent ions such as Al3+ and Fe3+. At a constant sintering temperature of 1100?°C, the YIG contents in the composites increased, thereby causing their luminescent properties to degrade and the saturation magnetizations to increase. For application to electronics, Ce:YAG-YIG composite thin films were integrated on quartz substrates by sputtering the ceramic target. The composite thin films exhibited both magnetic and luminescent properties after annealing. These techniques facilitate the incorporation of multifunctional nanocomposites into various devices. 相似文献
85.
Pd/CeO2/Ta/Si model catalysts were prepared by spin coating and sputter deposition method, and characterized by means of AFM, SEM and in situ XPS, especially focusing on the redox properties of Ce and Pd elements. Compared with thin CeO2 films (about 2.2nm), the thicker ones (about 22nm) maintained Ce4+ oxidation state even after treatment with H2 up to 500°C while the presence of Pd facilitated the reduction of ceria. The reduction of ceria brought about following that of PdO, which was explained by the spillover of hydride in Pd to CeO2 originating from hydrogen adsorption on the Pd surface. Compared with the sputter deposition method, spin coating produced the smaller size of Pd particles, thus leading to formation of the stable PdO species against hydrogen. Based on these results, a schematic model of Pd/CeO2/Ta/Si was suggested and it might be assumed that spin coating method provided with an environment similar to the conventional impregnation. 相似文献
86.
Polyvinylidene fluoride (PVDF)‐based nanofiber was successfully produced for a high performance and stable humidity sensor via a solution‐blowing spinning method. The performances of the manufactured sensors, including the impedance change with relative humidity (RH), moisture stability, and response and recovery times, were investigated. To improve charge carrier transfer, which is the main mechanism of humidity sensing, especially under low RH conditions, lithium chloride was used and displayed the best linearity in the impedance change with RH. Fast response and recovery times of 1.7 and 16.1 s were, respectively, achieved with zinc oxide nanoparticles. Furthermore, the sensors showed excellent moisture stability, owing to the hydrophobicity of PVDF, and this was demonstrated via repeatability testing and scanning electron microscopy. The humidity sensing mechanism was discussed using complex impedance spectra. POLYM. ENG. SCI., 59:304–310, 2019. © 2018 Society of Plastics Engineers 相似文献
87.
In this study, cells from the stromal vascular fraction of human subcutaneous tissues were induced to differentiate toward
adipose cells in vitro for 2 weeks. During adipogenic differentiation, we followed the chronological changes in their morphology
with Coherent anti-Stokes Raman scattering (CARS) microscopy and checked the PPAR-γ and UCP-1 expression with RT-PCR. On day
4 after inducing adipogenic differentiation, CARS imaging showed multiple small lipid droplets (LD) distributed peripherally
along the cellular membrane. PPAR-γ began to express at this time and increased until day 14 at a steady rate. On day 7, the
cells appeared as brown adipocytes with numerous small LD throughout the cytoplasm, and the mRNA level of UCP-1 rose abruptly
by 6- to 7-fold. After an additional 7 days, CARS imaging showed the development of a large LD, which is characteristic of
white adipocytes, and the mRNA level of UCP-1 slumped significantly. These results demonstrate the possibility that ADSC pass
through a brown adipocyte-like stage while differentiating into white adipocytes. 相似文献
88.
Correlation between IR peak position and bond parameter of silica glass: Molecular dynamics study on fictive temperature (cooling rate) effect 下载免费PDF全文
Jiawei Luo Yuxing Zhou Carlo G. Pantano Seong H. Kim 《Journal of the American Ceramic Society》2018,101(12):5419-5427
The fictive temperature of glass is a consequence of its thermal history (cooling rate, primarily) and has a direct effect on physical and chemical properties of the glass. But, it is not easy to measure. The ability to nondestructively and spectroscopically measure it at room temperature would be of great benefit. Although empirical correlations have been established between fictive temperature and selected absorption peaks in the infrared spectra of silica glass, the fundamental understanding for this correlation has not been reported. Here, we use molecular dynamics simulations to show that the blue shift in the Si–O–Si asymmetric stretching peak of pure silica glass, which is known to correlate with a decrease in fictive temperature, can be attributed to a decrease in the average length of the Si–O bond in the silica network, not changes in the density or the Si–O–Si bond angle. The decrease in density at higher fictive temperatures of silica is associated with a decreased population of 5‐ and 6‐membered rings and broadening of the ring‐size distribution, and an increase in the average Si–O–Si bond angle. 相似文献
89.
A polysaccharide‐immobilized chiral stationary phase (CSP) was prepared by the surface‐initiated atom transfer radical polymerization (SI‐ATRP), in pyridine, of cellulose 2,3‐bis(3,5‐dimethylphenylcarbamate), having a polymerizable vinyl group, on the surface of SiO2 support. The successful preparation of the CSP was confirmed via Fourier transform infrared spectroscopy, field‐emission scanning electron microscopy, X‐ray photoelectron spectroscopy, elemental analysis and thermal analysis. The chiral recognition ability of the prepared CSP was evaluated with high‐performance liquid chromatography using 10 racemates with various mobile phases of hexane/alcohol, hexane/tetrahydrofuran and hexane/chloroform. As a result, this CSP prepared using SI‐ATRP can be used in tetrahydrofuran and chloroform solutions as eluents. Copyright © 2011 Society of Chemical Industry 相似文献
90.
Ji Yeong Lee Won Kyung Seong In-Suk Choi Ranajay Ghosh Ashkan Vaziri Cheol-Woong Yang 《The Journal of Adhesion》2015,91(5):369-380
We report the deformation behavior and mechanical properties of a polymeric micropillar, which measures approximately 10 μm by 30 μm in size by measuring the loading/unloading response using an in situ force measurement system. When the single poly(dimethylsiloxane) (PDMS) micropillar was subjected to compression, we observed a periodic wrinkle and global (Euler) buckling at the sidewall. During unloading, we found the pull-off force (adhesion force) to increase for higher values of preloading and also for lower loading/unloading rates. From the slope of the load–displacement curves measured in situ, we calculated the effective elastic stiffness of the PDMS micropillar to be about 2.03 MPa. In addition to the current work, we report that this method can be used more broadly for in situ measurement of the intrinsic mechanical and adhesion properties of polymers and other relatively soft materials. 相似文献