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61.
Ik Hyun Kwon Hye Ryoung Park Young Youp Song 《Russian Journal of Electrochemistry》2013,49(3):221-227
LiNi1 ? y Ti y O2 (0.000 ≤ y ≤ 0.100) and LiNi0.990M0.010O2 (M = Zn, Al, and Ti) were synthesized by the combustion method. The effects of Zn, Al and Ti substitution for Ni of LiNiO2 on the electrochemical properties of LiNiO2 were investigated. LiNi0.995Ti0.005O2 has the largest first discharge capacity (188.1 mA h/g) among the Ti-substituted samples. LiNi0.990Ti0.010O2 has a relatively large first discharge capacity (185.5 mA h/g) and a relatively good cycling performance. Among LiNi0.990M0.010O2 (M = Ni, Zn, Al, and Ti), LiNiO2 has the largest discharge capacities at a rate of 0.1 C from n = 1(189.3 mA h/g) to n = 10. LiNi0.990Al0.010O2 has the lowest discharge capacities from n = 1 to n = 10, but it has the best cycling performance. LiNi0.990Zn0.010O2 showed poor crystallinity, LiNi0.990Ti0.010O2 showed high cation mixing, and LiNi0.990Al0.010O2 had good crystallinity and showed low cation mixing. Fewer occurrence of phase transitions and the least change of the ?dx/|dV| vs. voltage curve at the second cycle from the curve at the first cycle of LiNi0.990Al0.010O2 suggest that Al substitution stabilizes the structure and leads to a good cycling performance. 相似文献
62.
Glutamic acid is readily converted into N-butenyl-2-pyrrolidi-none-5-carboxaldehyde. The novel butenyl protecting group allows the synthesis of this aldehyde which can be olefinated using standard Wittig methodology. 相似文献
63.
A series of self-healable polyurethane (SHPU)/modified graphene (MG) nanocomposites were synthesized from poly(tetramethylene glycol) (PTMG) and 4,4′-methylene diphenyl diisocyanate (MDI) with minute amounts (0–1 wt%) of MG which was chemically modified graphene oxide (GO) with phenyl isocyanate and reduced in the presence of phenylhydrazine. 相似文献
64.
Taek Kwan Kwon 《Journal of Dispersion Science and Technology》2013,34(4):480-484
Monoolein (MO) cubic phase incorporating hydrophobically modified chosan (Hm chitosan) was prepared to obtain a pH-dependent release. Following calorimetric study, Hm chitosan had little effect on the crystal structure of MO cubic phase under acidic condition where Hm chitosan is readily soluble. At a higher pH (e.g., pH 9.0), however, the crystal structure of MO cubic phase was disturbed, possibly due to the insolubilization of Hm chitosan at the alkali condition. Whether the dye included in the cubic phase is anionic (amaranth) or cationic (methylene blue), the release from the cubic phase was suppressed as the pH of release medium increased. The structural change of cubic phase caused by the insolubilization of Hm chitosan, or the blockage of the water channel of the cubic phase by precipitated Hm chitosan would be responsible for the suppressed released. 相似文献
65.
Adsorption and desorption of ions at interface between liquid crystal and alignment layer in liquid crystal displays play a crucial role in residual direct current voltage associated with image sticking. In this article, the dependency of such adsorption and desorption of ions on resistivity of alignment layer and sign of liquid crystal dielectric anisotropy in the fringe-field liquid crystal cell has been investigated. Our studies show that the time constant of ions during adsorption and desorption depends upon resistivity and dielectric constant of liquid crystal and alignment layer, and most strongly influenced by the resistivity of alignment layer such that the one with lower resistivity in two orders shows much faster adsorption and desorption at the interface than that of the one with higher resistivity. 相似文献
66.
Chong-Kwang Lee Soon-Sik Kwon Seung-Tae Shin E-Joon Choi Soonnam Lee Liang-Chy Chien 《Liquid crystals》2013,40(8):1007-1013
Banana-shaped achiral compounds, the 1,3-phenylene bis[4-(alkenyloxyphenyliminomethyl)benzoate]s, were synthesized with varying length of the alkenyl group; their ferroelectric properties are described. The smectic mesophases, including a switchable chiral smectic C (SmC*) phase, were characterized by differential scanning calorimetry, polarizing optical microscopy and the triangular wave method. The presence of vinyl groups at the ends of the linear side-wings in the banana-shaped achiral molecules, containing a Schiff's base mesogen, induced a decrease in melting temperature and formation of the switchable SmC* phase in the melt. The compound having the octenyloxy group exhibited a spontaneous polarization of 120 nC cm?2 on reversal of an applied electric field. 相似文献
67.
Sungchil Kang Alexander Efremov Sun Jin Yun Jinyoung Son Kwang-Ho Kwon 《Plasma Chemistry and Plasma Processing》2013,33(2):527-538
An investigation of etching behaviors for Mo and Al2O3 thin films in O2/Cl2/Ar inductively coupled plasmas at constant gas pressure (6 mTorr), input power (700 W) and bias power (200 W) was carried out. It was found that an increase in Ar mixing ratio for Cl2/Ar plasma results in non-monotonic etching rates with the maximums of 160 nm/min at 60 % Ar for Mo and 27 nm/min at 20 % Ar for Al2O3. The addition of O2 in the Cl2/Ar plasma causes the non-monotonic Mo etching rate (max. 320 nm/min at 40–45 % O2) while the Al2O3 etching rate decreases monotonically. The model-based analysis of etching kinetics allows one to relate the non-monotonic etching rates in Cl2/Ar plasma to the change in the etching regime from the ion-flux-limited mode (at low Ar mixing ratios) to the neutral-flux-limited mode (for high Ar mixing ratios). In the Cl2/O2/Ar plasma, the non-monotonic Mo etching rate is probably due to the change in reaction probability. 相似文献
68.
Hui‐Jun Yun Yun‐Ji Lee Seung‐Jin Yoo Prof. Dae Sung Chung Prof. Yun‐Hi Kim Prof. Soon‐Ki Kwon 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(39):13242-13248
We describe herein the synthesis of novel donor–acceptor conjugated polymers with dithienobenzodithiophenes (DTBDT) as the electron donor and 2,1,3‐benzothiadiazole as the electron acceptor for high‐performance organic photovoltaics (OPVs). We studied the effects of strategically inserting thiophene into the DTBDT as a substituent on the skeletal structure on the opto‐electronic performances of fabricated devices. From UV/Vis absorption, electrochemical, and field‐effect transistor analyses, we found that the thiophene‐containing DTBDT derivative can substantially increase the orbital overlap area between adjacent conjugated chains and thus dramatically enhance charge‐carrier mobility up to 0.55 cm2 V?1 s?1. The outstanding charge‐transport characteristics of this polymer allowed the realization of high‐performance organic solar cells with a power conversion efficiency (PCE) of 5.1 %. Detailed studies on the morphological factors that enable the maximum PCE of the polymer solar cells are discussed along with a hole/electron mobility analysis based on the space‐charge‐limited current model. 相似文献
69.
So Young An Seung Man Noh Joon Hyun Nam Jung Kwon Oh 《Macromolecular rapid communications》2015,36(13):1255-1260
Polymer‐based crosslinked networks with intrinsic self‐repairing ability have emerged due to their built‐in ability to repair physical damages. Here, novel dual sulfide–disulfide crosslinked networks (s‐ssPxNs) are reported exhibiting rapid and room temperature self‐healability within seconds to minutes, with no extra healing agents and no change under any environmental conditions. The method to synthesize these self‐healable networks utilizes a combination of well‐known crosslinking chemistry: photoinduced thiol‐ene click‐type radical addition, generating lightly sulfide‐crosslinked polysulfide‐based networks with excess thiols, and their oxidation, creating dynamic disulfide crosslinkages to yield the dual s‐ssPxNs. The resulting s‐ssPxN networks show rapid self‐healing within 30 s to 30 min at room temperature, as well as self‐healing elasticity with reversible viscoelastic properties. These results, combined with tunable self‐healing kinetics, demonstrate the versatility of the method as a new means to synthesize smart multifunctional polymeric materials.
70.