• Advances in nano research
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• v.13 no.2
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• pp.187-197
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• 2022

The synthesis of organic and hybrid organic-inorganic perovskites directly from solution improves the cost- and energy-efficiency of processing. To date, numerous research efforts have been devoted to investigating the influence of the various solvent parameters for the synthesis of lead halide perovskites, focused on the effects of different single solvents on the efficiency of the resulting perovskites. In this work, we investigated the effect of solvent blends for the first time on the structure and phase of perovskites produced via the Lewis base vapor diffusion method to develop a new synthetic approach for water-stable CsPbBr₃ particles with nanometer-sized dimensions. Solvent blends prepared with DMF and water-miscible solvents with different Gutmann's donor numbers (D_N) affect the Pb ions differently, resulting in a variety of lead bromide species with various colors. The use of a DMF/isopropanol solvent mixture was found to induce the formation of the Ruddlesden-Popper perovskite based on lead bromide. This perovskite undergoes a blue color shift in the solvated state owing to the separation of nanoplatelets. In contrast, the replacement of isopropanol with DMSO, which has a high DN, induces the formation of spherical CsPbBr₃ perovskite nanoparticles that exhibit green emission. Finally, the integration of acetone in the solvent system leads to the formation of lead bromide complexes with a yellow-orange color and the perovskite CsPbBr₃.

• Membrane Journal
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• v.34 no.4
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• pp.216-223
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• 2024

In comparison to commonly employed polypropylene (PP) material, polymethylpentene (PMP) exhibits low surface energy and reduced crystallinity, allowing fabrication of asymmetric membranes with a dense skin layer. However, its higher melting point poses significant challenges with respect to polymer processability. In this work, we utilized the N-TIPS method, which combines the advantages of non-solvent induced phase separation (NIPS) and thermally induced phase separation (TIPS), to fabricate PMP membranes. Cyclohexane was employed as the solvent for preparing the PMP dope solution, while water, ethanol (EtOH), and isopropanol (IPA) were used as nonsolvents. When cyclohexane-immiscible water was used as the nonsolvent, the resulting membrane exhibited TIPS morphology with unifrom pore structure but lacked suface uniformity. In contrast, when cyclohexane-miscible alcohols (EtOH, IPA) were employed, the membranes displayed NIPS morphology with a dense skin layer with higher mechanical strength. Furthermore, the effect of polyethylene glycol (PEG) as a pore forming agent was investigated to better control the surface pore size.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2623-2628
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• 2013

Three di-acyl chlolide reagents, adipoyl chloride, terephthaloyl chloride and isophthaloyl chloride, were used as spacer reagents to prepare bonded type of three cellulose (3,5-dimethylphenyl)carbamate (CDMPC) chiral stationary phases (CSPs). The CDMPC CSPs were prepared using these three acid chlorides as spacer agents at the 6-position of the primary hydroxyl group on the glucose unit of cellulose regioselectively. The chiral recognition ability of the prepared CSPs for five racemates was evaluated by normal-phase high-performance liquid chromatography (HPLC) with the following mobile phases: hexane/isopropanol (IPA), hexane/IPA/tetrahydrofuran (THF) and hexane/IPA/chloroform. The result showed that these prepared CSPs can be used in THF and chloroform solutions and the chiral recognition abilities of the CSPs were improved depending on the eluents and chiral samples.

• Journal of the Korean institute of surface engineering
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• v.37 no.2
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• pp.76-79
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• 2004

Nickel chloride coated protein chip plate was developed by using a spin coating method. The ability of histidine tagged protein adsorption was investigated at various solvents. The surface of plate has a large aggregated nickel complex with high density in water. However, the surface of plate has a very small size of aggregated nickel complex with low density in isopropanol. The ability of protein adsorption decreased as increasing the size of alkyl chain in various alcohol solvents. The mechanism on the ability of protein adsorption at the plate surface is discussed.

• Membrane Journal
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• v.12 no.4
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• pp.193-206
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• 2002

Pervaporation separation is one of promising membrane technology for the energy saving processes and it has been developed to separate complex mixture systems including azeotropic mixture, close-boiling mixture, aqueous organic mixtures etc. Many researchers focused on dehydration pervaporation separation and they commercialized ethanol dehydration and isopropanol recycling processes. Nowadays, petroleum separation and volatile organic compound removal using pervaporation membranes is one of the emerging application of pervaporation separation. We reviewed the development and application of pervaporation membranes.

• Microbiology and Biotechnology Letters
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• v.24 no.6
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• pp.687-692
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• 1996

Xylanase (EC 3.2.1.8) was purified approximately 4.3 fold from Aspergillus niger SFN-416 by ammonium sulfate fractionation, Sephadex G-100 gel filtration and DEAE-Sephacel ion exchange chromatography. Molecular weight of the enzyme was approximately 42,000 daltons. The optimum pH and temperature of the enzyme activity were 5.5 and 50$\circ$C, respectively. The enzyme activity was enhanced by Fe$^{2+}$, and inhibited by Hg$^{2+}$. The activity was decreased by addition of methanol, ethanol, isopropanol and 1-butanol at a concentration of 10%(v/v).

• Journal of environmental and Sanitary engineering
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• v.14 no.4
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• pp.35-40
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• 1999

For application of a yellow pigment as food additives, stability of a water-soluble yellow pigment from Bacillus sp. PY123 was investigated. The yellow pigment from Bacillus sp. PY123 was purified with pH treatment, activated carbon and silica gel column chromatography. The partial purified yellow pigment appeared only one spot on silica gel TLC after 12 evaporation and under irradiation of UV 253nm at dark room. Rf value of the pigment was measured at 0.04 and 0.12 with development of a solvent mixture (Butanol : Acetic acid : water = 4 :1:5) and a solvent mixture (Isopropanol : Ammonia : Water = 9 :1: 2), respectively, The partial purified pigment appeared a white fluorescence under UV365nm irradiation. The partial purified yellow pigment had a main peak and a minor peak on HPLC using 20mM phosphate buffer(pH 7.0) at 1ml/min flow rate. The partial purified pigment was stable at heat treatment, acidic pH, oxide-reductants and surfactants.

• Journal of the Korean Ceramic Society
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• v.33 no.12
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• pp.1319-1324
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• 1996

Silica aerogels were synthesis by the sol-gel-supercritical drying process using isopropanol as a solvent. Effets of the heat-treatment and the surface modification through propoxylation on the structural reinforcement as well as the surface hydrophobic/hydrophilic characteristics of aerogels were investigated. Silica aerogels synthesized by supercritical drying were hydrophobic but aerogels heat-treated above 20$0^{\circ}C$ were transformed to be hydrophilic. In particular it was found that the skeletal structure of aerogels heat-treated at 50$0^{\circ}C$ was strong enough not to crack after adsorbing a large amount of water vapor. Hydrophilic aerogels modified by propoxylation at 28$0^{\circ}C$ for 20 h were reversed to the hydrophobic form. Transition between hydrophobicity and hydrophilicity was reversible. The hydrophobicvity and the hydrophilicity of silica aerogels were attributed to the Si-Oh bond and the nonpolar C-H bond groups of orgainc species respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.426-426
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• 2008

Blend membranes were prepared by solvent casting method from sulfonated fluorinated poly(arylene ether)s (SDFF) and chemically modified polyvinylidene fluoride (mPVdF) in isopropanol and were evaluated as proton exchange membrane electrolytes in PEMFC. $^1H$-NMR, differential scanning calorimeter and thermogravimetric analysis was utilized to characterize the structure of the blend membranes (SDFF/mPVDF) and effects of mPVDF content on the properties of the membrane such as water uptake and proton conductivity were also investigated.

• Bulletin of the Korean Chemical Society
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• v.26 no.2
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• pp.238-240
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• 2005

The enthalpies of transfer, ${\Delta}H_t{\Theta}$, of NaI from water to aqueous methanol, ethanol and isopropanol, iPrOH, systems are reported. These data have been analysed in terms of the new solvation theory. These data are considered in terms of the new developed solvation theory including variable ($\alpha$n + $\beta$N), the net effect of the solute on the solvent-solvent bonding, is positive if there is a net breaking or weakening of solvent-solvent bonds. The solvation parameters recovered from the analyses indicate that the net affect of NaI on solvent structure is a breaking of solvent-solvent bonds and that NaI is preferentially solvated by water in all aqueous alcohol systems considered. ($\alpha$n + $\beta$N) values increase with increasing in the size of the alcohol alkyl residue from methanol to iPrOH.