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131.
P.W. Ruch M. Hahn M. Holzapfel H. Kaiser B. Schmitt R. Kötz A. Wokaun 《Electrochimica acta》2007,53(3):1074-1082
The intercalation of (C2H5)4N+ and BF4− from acetonitrile (AN) and propylene carbonate (PC) solutions into bound graphite electrodes during cyclic voltammetry was investigated by in situ X-ray diffraction (XRD) using synchrotron radiation. The disappearance of the 0 0 2 reflection of graphite in the XRD patterns upon intercalation of (C2H5)4N+ indicates that the cations are accumulated between the graphene layers. For the intercalation of BF4−, the appearance of 0 0 l reflexes in the intercalated state provides clear evidence of staging. In both cases, the in-plane periodicity was not significantly altered by the intercalation process apart from slight changes in the CC bond length. The intercalation of BF4− from the PC-based electrolyte was found to have the least destructive effect on the periodicity of the graphite structure during initial cycling in the anodic potential range along with the highest charge/discharge efficiency. 相似文献
132.
The crystal structure of poly(pentamethylene 2,6-naphthalate) (PPN) was determined by using X-ray diffraction and molecular modeling. The unit cell of PPN was found to be triclinic (
space group) with dimensions of a=0.457 nm, b=0.635 nm, c=2.916 nm, =121.6°, β=90.4°, γ=87.6°, and the calculated crystal density was 1.311 g cm−3. The unit cell contains one polymer chain with two repeating units. In the unit cell, the PPN backbone takes gauche/gauche conformation in the middle part of each pentamethylene unit, and two naphthalene rings are in face-to-face arrangement. 相似文献
133.
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
134.
Bassam Alkotaini Hyunseok Koo Beom Soo Kim 《Korean Journal of Chemical Engineering》2016,33(5):1669-1673
Polyhydroxyalkanoates (PHAs) are linear polyesters synthesized by microbial fermentation of various substrates. PHAs are accumulated in microbial cells in order to store carbon and energy for future use. We used acid-pre-treated red alga (Gelidium amansii) as a cheap, abundant carbon source to produce PHA via batch and fed-batch cultivation of Bacillus megaterium KCTC 2194. After acid treatment of 10% (w/v) G. amansii, 25.5 g/L galactose, 3.6 g/L glucose, 6 g/L 5-HMF, and 1.05 g/L levulinic acid were formed. In batch culture at pH 7, the dry cell weight (DCW) and PHA content increased to 5.5 g/L and 51.4%, respectively. The cell concentration was enhanced by fed-batch cultivation using two feeding strategies: pH-stat and intermittent feeding. When the pH-stat feeding strategy was employed to add concentrated hydrolysate to the fermentor, DCW increased to 8.2 g/L, with 53.2% PHA content. When concentrated hydrolysate was fed using the intermittent feeding strategy, higher DCW (10.1 g/L) was obtained, along with a slight increase of PHA content to 54.5%. This study demonstrates that red algae could be used after simple acid treatment, to produce PHA without steps for enzymatic hydrolysis and inhibitor removal. 相似文献
135.
Yehoon Kim Seungjoo Haam Woo-Sik Kim Kee-Kahb Koo 《Korean Journal of Chemical Engineering》2003,20(6):1111-1117
Crystallization of L-ornithine-L-aspartate (LOLA) by drowning out was performed for the production of the anhydrous form of
LOLA. The needle-like LOLA crystals were formed and spherically agglomerated during precipitation in a semibatch crystallizer.
The primary crystal size in the agglomerate remains unchanged after completion of the crystallization. Therefore, the agglomeration
process of primary crystals played an important role for controlling LOLA crystal size. The agglomeration of LOLA crystals
was governed by not only the physico-chemical parameters such as the temperature and feed concentration, but also the hydrodynamic
parameters such as agitation speed and feeding rate. The crystal size and the shape have been shown to be important factors
in product impurity and flowability. Thus, the optimum condition of LOLA crystallization process by drowning-out could be
obtained. 相似文献
136.
137.
Polyurethane macroiniferter/poly(methyl methacrylate) block copolymer dispersions with inverse core‐shell morphologies were obtained from 1,1,2,2,‐tetraphenylethane‐1,2‐diol, dimethylol propionic acid, 4,4′‐diphenylmethane diisocyanate, and poly(propylene glycol) via a living radical mechanism. Molecular weight, particle size and dispersion viscosity, and thermal, mechanical, and dynamic mechanical properties of the dispersion cast films are reported as a function of copolymerization time. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1971–1975, 2003 相似文献
138.
We investigated the effects of the different content ratios of 2‐ethylhexylacrylate (2‐EHA) and 2‐ethylhexylmethacrylate (2‐EHMA) on the relationships among the photopolymerization rate, morphology of liquid crystals (LCs) droplets, and electro‐optical properties of trifunctional urethane acrylate‐based polymer‐dispersed liquid crystal (PDLC) systems. Photo‐differential scanning calorimetry (DSC) analysis and resistivity measurement revealed that increasing 2‐EHMA content gradually decreased the photocure rate of trifunctional urethane acrylate‐based PDLCs, which prolonged the phase separation between the LC molecules and the prepolymers. Morphological observations and electro‐optical measurements demonstrated that trifunctional urethane acrylate‐based PDLCs with the 2‐EHA:2‐EHMA ratios from 4:1 to 3:2 in weight percent formed the favorable microstructures of LC droplets being within the range of 1–5 µm to scatter light efficiently and showed the satisfactory off‐state opacity and on‐state transmittance and the relatively low‐driving voltage. The microstructures of LC droplets and electro‐optical properties of trifunctional urethane acrylate‐based PDLCs could be usefully optimized by controlling the photocure rate using the different 2‐EHA/2‐EHMA content ratios. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3098–3104, 2013 相似文献
139.
A cocured joint whose manufacturing process is simpler than that of an adhesively bonded joint is attractive for composite structures due to its several benefits. Fatigue behavior in the cocured joint is important because under alternating loads it will fail at stress levels much lower than it can withstand under monotonic loading. Although some researchers have recently reported on cocured joints, there are only a few articles published on the fatigue characteristics of cocured joints. In this article, effects of bond parameters on fatigue characteristics of a steel-composite cocured double lap joint under cyclic tensile loads were experimentally investigated. In order to observe stress distributions near the interface edge of the cocured double lap joint, finite element analysis was also performed. We considered the surface roughness of the steel adherend and the stacking sequence of the composite adherend as bond parameters. A fatigue failure mechanism of the cocured double lap joint was explained systematically by investigating the surfaces of failed specimens and stress distributions at the interface edge. Failure criteria of the cocured double lap joint under cyclic tensile loads were shown graphically. 相似文献
140.
Seung Hun Oh Jae Seong Kim Jin Suk Chung Sung Hong Hahn 《Chemical Engineering Communications》2013,200(3):327-335
Transparent nanophase TiO2 thin films on soda lime glass were prepared from titanium tetraisopropoxide (TTIP) by a sol-gel dip-coating method. The TiO2 films had amorphous phase up to 400°C and anatase phase at 500°C. The amorphous TiO2 films obtained at 300–400°C showed considerable photoactivity for the degradation of formic acid. The photoactivity of the TiO2 films was enhanced with increasing calcination temperature from 300° to 500°C. The crystallinity of the anatase films at 500°C was improved with increasing calcination time up to 2 h and reduced with a further increase in calcination time to 4 h due to the significant formation of sodium titanate phase as a result of sodium diffusion. The four-time-dipping anatase films at 500°C exhibited the greatest photoactivity at the calcination time of 2 h. Sodium diffusion into TiO2 films was retarded by a SiO2 underlayer of 50 nm in thickness. 相似文献