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21.
Xueming Niu Shuqian Wan Xiaona Rong Mian Lin Nabila Mehwish Kun Wei Bae Hoon Lee 《大分子材料与工程》2021,306(9):2100193
It remains a challenge to maintain the antiadhesion properties of superhydrophobic films after exposure to bacterial environments. In this work, superhydrophobic bactericidal polymer films via the simple incorporation of polyvinylpyrrolidone-iodine (PVP-I) or iodine into polytetrafluoroethylene (PTFE) are fabricated to improve their antiadhesive and antibacterial capability. Superhydrophobic iodine-embedded films, polytetrafluoroethylene/polyvinylpyrrolidone-iodine and polytetrafluoroethylene-iodine (PTFE/PVP-I and PTFE-I), show excellent antiadhesive and bactericidal performances even post exposure to bacterial solutions as compared to iodine-free counterparts by controlling the release of iodine. Especially, superhydrophobic PTFE/PVP-I films display a more sustained iodine release profile and significant antibacterial properties against gram-positive (S. aureus, methicillin-resistant S. aureus (MRSA)) and gram-negative (E. coli) bacteria. Such a facile combination of antiseptic agents and superhydrophobic surface could be widely used for antiseptic biomedical applications. 相似文献
22.
Sk S. Hossain Chang-Jun Bae P. K. Roy 《International Journal of Applied Ceramic Technology》2021,18(5):1783-1791
Lightweight insulation refractories are essential for high-temperature performance to reduce energy consumption. This study investigates a new insulation material, that is, solid waste rice husk ash (RHA) derived lightweight refractory castable, replacing traditional insulation refractory brick. The RHA is generated after the burning of rice husk as biomass fuel. The RHA is used as an aggregate and alkali-extracted silica sol from RHA as a binder to fabricate the insulation castable. The nanosilica containing (~30 wt%) sol is employed to synthesize the refractory castable by varying the sol amount (2.5-12.5 wt% silica from sol). The castable specimens are cast by a vibro-caster and fired at 900-1200°C in a muffle furnace. The physic-mechanical and thermal conductivity (κ) of the castable is investigated. At 1100°C with 10 wt% dry sol retaining sample shows an excellent apparent porosity (~65%), low bulk density (~ 0.8 g/cm3), and κ (0.136 W/m k) with sustainable compressive strength (6 MPa). The acquired results are a good match with the literature (other wastes-derived insulation materials) and industrial (silica insulation brick) obtained data. These promising outcomes may inspire the refractory industries for using RHA as an aggregate and RHA extracted sol as a binder for making insulation castable. 相似文献
23.
The binary lanthanide catalyst for 1,3‐butadiene was invented for 40 years ago. However, it has not been employed in commercial application due to its poor solubility and low activity. Nanosized neodymium chloride (NdCl3) was prepared in tetrahydrofuran (THF) medium through dissolution, chelation, and colloidal formation steps. Anhydrous NdCl3 was dissolved in THF, and ca. 1.5 THF molecules were coordinated. In the colloidal formation step, THF was slowly replaced with the addition of cyclohexane, and pale blue nuclei, nanosize below 200 nm, were formed. The structural studies for NdCl3 · xTHF using X‐ray powder diffraction (XRD) and scanning electron microscope (SEM) indicate that high ordered crystallinity is decreased with reduced particle size from trigonal prismatic to porous sphere structure. Nano NdCl3, obtained as colloidal state in cyclohexane, was activated with Al(iBu)3 and Al(iBu)2H at room temperature and employed for 1,3‐butadiene solution polymerization. The nanosized Nd catalysts showed high activity (1.0 ~ 1.3 × 105 g/Nd mol · h), which is comparable to that of the ternary neodymium catalyst Nd(neodecanoate)3/AlEt2Cl/Al(iBu)3. The microstructures of polybutadiene, cis, trans, and vinyl, are about 96.0, 3.5, and 0.5%, respectively. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1279–1283, 2005 相似文献
24.
Neung‐Ju Lee Ja‐Chul Koo Sung‐Suk Ju Seong‐Bae Moon Won‐Jei Cho In‐Cheol Jeong Song‐Jae Lee Moo‐Youn Cho Emmanuel A Theodorakis 《Polymer International》2002,51(7):569-576
The attachment of anticancer agents to polymers is a promising approach towards reducing the toxic side‐effects and retaining the potent antitumour activity of these agents. A new tetrahydrophthalimido monomer containing 5‐fluorouracil (ETPFU) and its homopolymer and copolymers with acrylic acid (AA) and with vinyl acetate (VAc) have been synthesized and spectroscopically characterized. The ETPFU contents in poly(ETPFU‐co‐AA) and poly(ETPFU‐co‐VAc) obtained by elemental analysis were 21 mol% and 20 mol%, respectively. The average molecular weights of the polymers determined by gel permeation chromatography were as follows: Mn = 8900 g mol?1, Mw = 13 300 g mol?1, Mw/Mn = 1.5 for poly(ETPFU); Mn = 13 500 g mol?1, Mw = 16 600 g mol?1, Mw/Mn = 1.2 for poly(ETPFU‐co‐AA); Mn = 8300 g mol?1, Mw = 11 600 g mol?1, Mw/Mn = 1.4 poly(ETPFU‐co‐VAc). The in vitro cytotoxicity of the compounds against FM3A and U937 cancer cell lines increased in the following order: ETPFU > 5‐FU > poly(ETPFU) > poly(ETPFU‐co‐AA) > poly(ETPFU‐co‐VAc). The in vivo antitumour activities of all the polymers in Balb/C mice bearing the sarcoma 180 tumour cell line were greater than those of 5‐FU and monomer at the highest dose (800 mg kg?1). © 2002 Society of Chemical Industry 相似文献
25.
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
26.
Hae Jin Kim Jin Bae Lee Young-Min Kim Myung-Hwa Jung Z. Jagličić P. Umek J. Dolinšek 《Nanoscale research letters》2007,2(2):81-86
We present synthesis, structure and magnetic properties of structurally well-ordered single-crystalline β-MnO2 nanorods of 50–100 nm diameter and several μm length. Thorough structural characterization shows that the basic β-MnO2 material is covered by a thin surface layer (∼2.5 nm) of α-Mn2O3 phase with a reduced Mn valence that adds its own magnetic signal to the total magnetization of the β-MnO2 nanorods. The relatively complicated temperature-dependent magnetism of the nanorods can be explained in terms of a superposition
of bulk magnetic properties of spatially segregated β-MnO2 and α-Mn2O3 constituent phases and the soft ferromagnetism of the thin interface layer between these two phases. 相似文献
27.
Highly Efficient Overall Water Splitting Through Optimization of Preparation and Operation Conditions of Layered Perovskite Photocatalysts 总被引:1,自引:0,他引:1
Jindo Kim Dong Won Hwang Hyun Gyu Kim Sang Won Bae Jae Sung Lee Wei Li Se Hyuk Oh 《Topics in Catalysis》2005,35(3-4):295-303
The layered perovskite materials were found to give the high photocatalytic activity in water splitting reaction under UV
irradiation, where the electronic structure of perovskite slab constructing the layered structure (the total cation valency)
was the most crucial factor to the high photocatalytic activity. Both the excessive cation valency and the layered structure
were required for active photocatalysts, while the slab thickness of layered perovskites had an insignificant effect on water-splitting
activity. In order to identify key variables that affected photocatalytic activity and to optimize the performance of (110)
layered perovskite, La2Ti2O7 was modified by various methods. The optimum amount of loaded nickel had a great effect and the amount depended on the surface
area of the perovskite phase. When an alkaline-earth element such as Ba, Sr, and Ca was doped on La2Ti2O7, the photocatalytic activity was enhanced markedly. Introduction of an alkaline hydroxide into the reaction system as an
external additive enhanced the activity further showing extremely high quantum yields close to 50%. 相似文献
28.
Fractionation of the MeOH extract of Homaxinella sp., a marine sponge, led to the isolation of a sodium salt of a new brominated FA (1), two new MG (2 and 4), and a new lysoPC (6). The geometry of the double bonds in 1 and 2 was defined by comparison of the NMR chemical shifts of the allylic carbons, nuclear Overhauser effect spectroscopy correlations
of the allylic protons, and coupling constants of the vinylic protons with those reported. Evidence mainly from NMR and MS
analyses established the planar structures of the compounds. Compounds 1, 2, 4, and 6 were evaluated for cytotoxicity against a panel of five human solid tumor cell lines. Only compound 1 showed moderate activity. 相似文献
29.
Seong-Youl Bae Du-Hyon Cho Hee-Taik Kim Hidehiro Kumazawa 《Korean Journal of Chemical Engineering》1994,11(2):127-130
Sorption equilibria and permeation rates for oxygen and carbon dioxide in polycarbonate membrane were measured at different
temperature between 30 and 60°C and at pressures up to 2.5 MPa. The pressure dependence of mean permeability coefficient to
oxygen obeyed the conventional dual-mode mobility model, whereas that to carbon dioxide followed a modified dual-mode mobility
model with concentration-dependent diffusivities, as that of polystyrene to the same gas did. 相似文献
30.
The key to the success of flip‐chip technology lies in the availability of sucessful underfill materials. However, the reliability of flip‐chip technology using current underfill materials is generally found to be lower than that of conventional wire‐bond connection packaging materials such as epoxy molding compound (EMC) because of the high coefficients of thermal expansion (CTE) and moisture absorption of cured underfill material. In this study desbimide (DBMI), which has a low melting point (about 80°C), was used in the underfill materials as a cohardener. As a result, DBMI‐added underfill can show excellent thermal reliability, which is due to the superior properties of the CTE, the elastic modulus, and water resistance. When the properties of a 2 wt % DBMI‐added underfill were compared with those of a typical underfill (epoxy/anhydride), the CTE value was reduced to less than one‐half at the solder reflow temperature (about 200°C), the elastic modulus was reduced to less than one‐half in the temperature region below the glass‐transition temperature, and the water resistance was improved twofold. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2617–2624, 2002 相似文献