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21.
Kang Ji-Hoon Hwang Jinyul Sung Hyung Jin Ryu Hoon 《The Journal of supercomputing》2021,77(9):9597-9614
The Journal of Supercomputing - Direct numerical simulations (DNS) of turbulent flows have increasing importance because they not only provide fundamental understanding of turbulent flows but also... 相似文献
22.
Fine structures of several plastic/rubber two -phase polymer systems were studied by means of direct observations of ultrathin sections under the electron microscope using osmium tetroxide staining and a hardening procedure developed recently by Kato. Samples used are several types of both ABS polymers and high -impact polystyrenes, and several PVC/rubber blends and the results were discussed in relation to their dynamic viscoelastic properties. It is suggested that these studies may fruitfully be extended to clarify the structure -to property relationships by use of this method. 相似文献
23.
Synthesis of silver/polymer colloidal composites from surface-functional porous polymer microspheres
This study presents a different colloidal silver (Ag)/polymer system where Ag nanoparticles are deposited uniformly onto surface-functional porous poly(ethylene glycol dimethacrylate-co-acrylonitrile) (poly(EGDMA-co-AN)) microspheres. The formation and morphology of the composite microspheres were characterized from electron microscopy and X-ray diffraction analyses. The significance of the present report is that owing to the high affinity between Ag and nitrile group (CN) on the large surface of the microspheres, the Ag nanoparticles having a face-centered cubic phase were incorporated evenly into the deep pores of the microspheres with fine size and size distribution. In the preservation test, the Ag/poly(EGDMA-co-AN) composite microspheres obtained showed an excellent anti-bacterial performance, elucidating a high applicability for a new preservative. 相似文献
24.
A model representing the wet-end section of a paper mill has been developed to characterize its dynamic behavior during the
grade change. The model is based on the mass balance relationships written for the simplified wetend white water network.
From the linearization of the dynamic model, higher-order Laplace transfer functions were obtained followed by the reduction
procedure to give simple lower-order models in the form of 1st-order or 2nd-order plus dead times. The dynamic response of the wet-end is influenced both by the white water volume and by the level
of wire retention. Effects of key manipulated variables such as the thick stock flow rate, the ash flow rate and the retention
aid flow rate on the major controlled variables were analyzed by numerical simulations. The simple dynamic model developed
in the present study can be effectively used in the operation and control.
This paper is dedicated to Professor Se Ki Moon on the occasion of his retirement from Hanyang University. 相似文献
25.
Jong-Ho Ryu Jong Hyun Seo Jae-Han Jeong Sung-Kap Kim Dong Nyung Lee 《Journal of Applied Electrochemistry》2004,34(9):879-884
A study has been made of the electrochemical etching of 99.99% aluminum foils at a current density of 50 mA cm–2in AlCl3–HCl solutions (1 m Cl–) at 80 °C. The solutions were made by dissolving metallic aluminum into 1m HCl solution, to give a Cl– concentration of 1 m. The number density of etch tunnels and the homogeneity of tunnel length decreased, and the mean pit size and its standard deviation increased with increasing Al3+ concentration. The results were discussed based on potential transients at a current density of 50 mA cm–2, current–potential curves at a scan rate of 10 m Vs–1 and electrochemical impedance spectra. 相似文献
26.
Rheological characteristics of two pretreated petroleum pitches, during their transformation to mesophase, have been studied
by using rotalional viscometer. Simultaneously, the formation, growth, coalescence of mesuphase spheres, and the alignment
of coalesced mesophase were observed by Hot-Stage-Cinema-Microscope, discussed with the results of viscosity change and the
Q.I. content. It is found that both pretreated pitches were Newtonian fluids at low temperature, but behaved pseudoplastics
as increase of mesophase content above 390C. Shear thinning behaviour was also apparent in the shear rate range of 1.9–20
sec−1 at temperature above 390C. The apparent viscosity-temperature curves of this pyrolysed pitches were much affected by the
pretreatment conditions. 相似文献
27.
Yongwon Seo Sung-Ho Jo Ho-Jung Ryu Hee Dal Bae Chong Kul Ryu Chang-Keun Yi 《Korean Journal of Chemical Engineering》2007,24(3):457-460
A bubbling fluidized bed reactor was used to study CO2 capture from flue gas by using a potassium-based solid sorbent, sorbKX35 which was manufactured by the Korea Electric Power
Research Institute. A dry sorbent, sorbKX35, consists of K2CO3 for absorption and supporters for mechanical strength. To increase initial CO2 removal, some amount of H2O was absorbed in the sorbent before injecting simulated flue gas. It was possible to achieve 100% CO2 removal for more than 10 minutes at 60°C and a residence time of 2 s with H2O pretreatment. When H2O pretreatment time was long enough to convert K2CO3 of sorbKX35 into K2CO3 · 1.5H2O, CO2 removal was excellent. The results obtained in this study can be used as basic data for designing and operating a large scale
CO2 capture process with two fluidized bed reactors.
This work was presented at the 6
th
Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006. 相似文献
28.
Bo Hyun Ryu Sang Yup Lee Dong Hyun Lee Gui Young Han Tae-Jin Lee Ki June Yoon 《Catalysis Today》2007,123(1-4):303-309
Carbon black has recently been reported to act as an effective catalyst for methane decomposition and to exhibit stable catalytic behavior despite carbon deposition, and thus it can be used for CO2-free production of hydrogen from natural gas. In this work, various carbon blacks with different primary particle size were investigated with respect to methane decomposition under atmospheric pressure from 1123 to 1223 K. Catalytic characteristics, such as activity, activation energy and reaction order, were investigated and compared. It was observed that with decreasing primary particle size (or increasing specific surface area), the specific activity increased and the activation energy decreased. The reaction orders for various pelletized, rubber-reinforcing carbon blacks were 0.6–0.7, about the same regardless of the primary particle size, while they were near 1 for fluffy carbon blacks. Fluffy carbon black showed higher activity and activation energy than the pelletized carbon black of the same primary particle size. Changes of the surface morphology during carbon deposition were observed by TEM. Variations of the number of active sites were discussed in regard of the primary particle size, carbon deposition and binder. The presence of different types of active sites was also suggested. 相似文献
29.
30.
Latent catalyst effects were investigated to improve the physical properties of halogen‐free epoxy molding compounds (EMCs) for semiconductor encapsulation. In this study, biphenyl‐type resins were used as the epoxy and hardener resin for halogen‐free EMCs to obtain high flame‐retardant properties and high filler contents. Latent catalyst effects were examined with two kinds of EMC compositions, halogen‐free EMCs and conventional EMC compositions. We used triphenylphosphine‐benzoquinone salt (TPP‐BQ) as a latent catalyst. Spiral flow and gel time were measured to investigate the change in moldability with the latent catalyst. We measured package fail, moisture absorption, and delamination for reliability evaluation and flexural strength, flexural modulus, and adhesion for mechanical properties to examine latent catalyst effects. An improvement in moldability, reliability, and the mechanical properties were observed in two types of halogen‐free EMCs with TPP‐BQ as a latent catalyst. These phenomena were seen in conventional EMCs, including o‐cresol novolac epoxy resin. The cure kinetics of these systems were investigated by differential scanning calorimetry with an isothermal approach to explain these phenomena. The results indicate that the improvement in moldability in halogen‐free EMCs with TPP‐BQ was due to the low conversion rate of this system, and the increase in mechanical properties was attributed to the high conversion of curing reaction. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2287–2299, 2005 相似文献