1,721,011 research outputs found
Optimization of Genetic Switching Systems based on SQP: A Synthetic Lambda-Switch System
No full textHow to synthesize an optimized genetic λ-switch system? A system-theoretic approach based on SQP
No full textCharacterization of PVdF(HFP) gel electrolytes based on 1-(2-hydroxyethyl)-3-methyl imidazolium ionic liquids
No full textPoly(vinylidenefluoride)-hexafluoropropylene (PVdF(HFP)) -ionic liquid gel electrolytes were prepared using ionic liquids based on 1-(2-hydroxyethyl)-3-methyl imidazolium tetrafluoroborate and 1-(2-hydroxyethyl)3-methyl imidazolium hexafluorophosphate. A conventional metathesis reaction was used to prepare these ionic liquids, which have high purity and exhibit a liquid state at room temperature. The prepared polymerionic liquid gel proved to be a free-standing and rubbery film in which the degree of transparency differed according to the ratio and type of ionic liquid used. TGA and FTIR analyses confirmed that the solvent, N,N-Dimethylacetamide (DMAC), used for mixing PVdF(HFP) polymer with ionic liquid was almost totally removed during the gelling and drying processes. SEM photographs were taken of the surface structure of the PVdF(HFP)-ionic liquid gel in order to evaluate the morphology of the film's surface according to the mixing ratio and the nature of the ionic liquid. The thermal behaviors of PVdF(HFP)-ionic liquid gels were observed to be similar to those of neat ionic liquids through DSC analysis, and the compatibility between the polymer and ionic liquid was investigated by XRD analysis. The ionic conductivities of all the gels were 10(-3)-10(-5) S cm(-1) in a temperature range of 20-70 degrees C.This work was supported by Grant R01-2003-000-10300-0 from the Basic Research Program of the Korea Science & Engineering Foundation, and was partially funded by the Brain Korea 21 Project. The authors thank KBSI (Korea Basic Science Institute) for assistance with NMR, FAB mass, and ion chromatography, and Reliability Assessment Center of KRICT (Korea Research Institute of Chemical Technology) for assistance with DSC and TGA
The effect of polydispersity on the static and dynamic behavior of dodecyl ethoxylates at the air-water interface
No full textThe effect of polydispersity of polyoxyethylene chain has been studied with dodecyl alcohol 7 ethoxylates (C12E7) having different homologue distribution at air-water interface. The CMCs and the cross-sectional areas of head groups of C12E7 decreased linearly with the polydispersity of oxyethylene chain. The headgroup areas, deduced from the Gibbs adsorption equation, became small due to the preferential adsorption of short chain molecules onto the surface, whereas the limiting areas of the pi-A isotherm at collapse did not change although the polydispersity of C12E7 increased, because they were averaged over all distributions. The effective chain length of oxyethylene decreased on the surface as the polydispersity of C12E7 increased. Also the polydispersity of oxyethylene chain increased the dynamic surface tension at the fresh surface while it decreased the equilibrium surface tension at the aged surface. (C) 2002 Elsevier Science B.V. All rights reserved
Facile one-pot synthesis of gold nanoparticles using alcohol ionic liquids
No full textWe developed a novel synthesis of Au nanoparticles using alcohol ionic liquids. The alcohol ionic liquids simultaneously serve as both reductants and protective agents, thereby significantly simplifying the process of nanoparticle preparation
Size-controlled electrochemical synthesis of palladium nanoparticles using morpholinium ionic liquid
No full textWe have successfully synthesized morpholinium ionic liquid-stabilized palladium (Pd) nanoparticles by electrochemical reduction. For characterization of Pd nanoparticles, FT-IR, UV-visible spectroscopy, and Transmission electron microscopy (TEM) were employed. The FT-IR spectrum of Pd nanoparticles indicated the surface binding of the IL to the nanoparticles. The UV-visible spectrum showed that nano-sized I'd particles were produced. The particle size was controlled by the adjustment of the current density, temperature, and electrolysis duration. The TEM images showed an average size of 2.0, 2.2, 2.4, 2.9, 3.5, 3.9, and 4.5 nm. Nearly a 0.5 run-sized control of the nanoparticle was achieved. The particle size increased with a decrease in the current density and an increase in temperature and electrolysis duration. The electron diffraction patterns of resulting nanoparticles indicated that the particles had a crystalline structure.This work was supported by Grant No. R01-2003-000-10300-0
from the Basic Research Program of the Korea Science & Engineering
Foundation and also partially funded by the Brain Korea
21 Project. We are grateful to KBSI (Korea Basic Science Institute)
for assistance with NMR, FAB mass, and ion chromatograph
Thermal and electrochemical properties of morpholinium salts with bromide anion
No full textThe present work is a study of the thermal properties and electrochemical stabilities of N-ethyl-N-methyl-morpholinium bromide ([Mor(1.2)][Br]), N-butyl-N-methylmorpholinium bromide ([Mor(1.4)][Br]), N-butyl-N-methylmorpholinium bromide ([Mor(1.8])[Br]), N-dodecyl-N-methylmorpholinium bromide ([Mor(1,12)] [Br]), and N,N-dihydroxyethylmorpholinium bromide ([DHEMor][Br]). The melting points, decomposition temperatures, and electrochemical stabilities of the salts were measured by DSC (differential scanning calorimetry), TGA (thermogravimetric analysis), and CV (cyclic voltammogram), respectively. All salts were decomposed below approximately 230.00 degrees C and their melting points were above 100.00 degrees C except [DHEMor][Br], which melted at 75.17 degrees C. [DHEMor][Br] appeared to possess the most wide liquid-phase range between melting point and decomposition temperature. The electrochemical windows of salts ranged from 3.3 V for [Mor(1)(8)(.)][Br] to 3.6 V for [Mor(1.4)][Br] and thus did not show any noticeable variation with cations used for salt synthesis
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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