• Current Photovoltaic Research
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• v.3 no.3
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• pp.71-74
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• 2015

Soluble polyaniline was synthesized by attaching titanium isoproxide ($Ti(OPr)_4$) to the amine group of the aniline. Approximately 1 to 1 molar ratio of aniline and $Ti(OPr)_4$ was mixed and polymerized with ammonium persulfate. The FTIR result showed clear difference between $TiO_2$-aniline composite ($TiO_2An$) and $TiO_2$-polyaniline composite ($TiO_2PAn$). Although the $TiO_2An$ had negligible UV-visible absorption, the $TiO_2PAn$ showed strong absorption in the UV-visible region. Photoluminescence (PL) peaks of $TiO_2An$ were shifted toward red with the reduction of the excitation energy, which could be due to the multiple emission centers. The luminescence peak shift stopped at 501 nm. The PL spectra of $TiO_2PAn$ exhibited three emission peaks at 2.88 eV (430 nm), 2.48 eV (501 nm) and 2.22 eV (558 nm). The new emission center (2.22 eV) was observed after polymerization. Field emission scanning electron microscope image showed crack-free composite film.

• Macromolecular Research
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• v.17 no.9
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• pp.638-645
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• 2009

We report the effect of the amount of the mesoporous material, SBA-15, on the basic traits of fully aliphatic polyimides (API). For this purpose, water soluble, fully aliphatic poly(amic acid) triethyl amine salts ($PAA_{(s)}$) were prepared and mixed with various amounts of SBA-15. Fully aliphatic polyimide hybrid composites containing the SBA 15-type mesoporous silica were synthesized successfully from bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride and alicyclic diamine, 4,4'-methylene bis(2-methylcyclohexylamine). The structure of the hybrid composites was confirmed by IR spectroscopic analysis. Scanning electron microscopy revealed the morphology of the compounds. The hybrid composites exhibited good thermal stability, reasonable transparency, and a low dielectric constant.

• Macromolecular Research
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• v.15 no.2
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• pp.160-166
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• 2007

Novel multiblock copolymers, based on segmented sulfonated hydrophilic-hydrophobic blocks, were synthesized and investigated for their application as proton exchange membranes. A series of segmented sulfonated poly(arylene ether sulfone)-b-polyimide multiblock copolymers, with various block lengths, were synthesized via the coupling reaction between the terminal amine moieties on the hydrophilic blocks and naphthalene anhydride functionalized hydrophobic blocks. Successful imidization reactions required a mixed solvent system, comprised of NMP and m-cresol, in the presence of catalysts. Proton conductivity measurements revealed that the proton conductivity improved with increasing hydrophilic and hydrophobic block lengths. The morphological structure of the multiblock copolymers was investigated using tapping mode atomic force microscopy (TM-AFM). The AFM images of the copolymers demonstrated well-defined nanophase separated morphologies, with the changes in the block length having a pronounced effect on the phase separated morphologies of the system. The self diffusion coefficient of water, as measured by $^1H$ NMR, provided a better understanding of the transport process. Thus, the block copolymers showed higher values than Nafion, and comparable proton conductivities in liquid water, as well as under partially hydrated conditions at $80^{\circ}C$. The new materials are strong candidates for use in PEM systems.

• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.124-130
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• 2001

The in vitro activities of 2,2'-dipyridyl, an iron-chelator, against clinical isolates of Trichomonas vaginalis, Candida albicans, and Gardnerella vaginalis was evaluated and compared with those of four other vaginal suppositories, ornidazole, clotrimazole, povidone-iodine, and $Cenacert^{\circledR}$ (Methylbezethonium Chloride mixed with 9-aminoacrydine undecylenate and hydrochloric acid N-myristyl-3-hydroxy butyl amine). The 2,2'-dipyridyl killed T. vaginalis and G. vaginalis at concentrations of $410\;{\mu}g/ml$ and $205\;{\mu}g/ml$, respectively, however, ths agent was less active against C. albicans (80% of which was inhiited at $410\;{\mu}g/ml$). The inhibition of these three pathogens by 2,2'-dipyridyl was similar to clotrimazole. In addition, the effect of 2,2'-dipyridyl on the ultrastructure of T. vaginalis, C. albicans, an G. vaginalis was examined. Transmission electron microscopy indicated that 2,2'-dipyridyl induced modifications of the cellular contents and cell envolope concumitant with the degradation of the three pathogens. These results suggest that 2,2'-dipyridyl has an inhibitory effect on C. albicans and G. vaginalis, as well as T. vaginalis.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.4
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• pp.21-27
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• 2014

As a part of the study on manufacture of low density paper by organic bulky agent treatment, the effects of cationic fatty acid bulky agent on physical and optical properties of handsheets were elucidated. The research on change of physical and optical properties of paper samples according to bulky agent concentration, pulp type, and pulp combination were carried out. The results demonstrated that an increase of the concentration of cationic fatty acid bulky agent was proportional to an increase of the bulky properties of paper samples while tensile strength decreased. Also, the more the treated concentration of cationic fatty acid bulky agent increased, the more the ISO brightness of paper samples decreased while the opacity increased. The effectiveness of bulky agent with softwood bleached kraft pulp (SwBKP) was higher than that with hardwood bleached kraft pulp (HwBKP). In addition, the effectiveness with mixed pulps was higher than that with single pulp.

• Polymer(Korea)
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• v.29 no.2
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• pp.172-176
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• 2005

Environmentally friendly water dispersion polyurethanes containing fluorine were prepared with a fluorinated polyol having $62\%$ of fluorine $(Fluorolink^{(R)}\;M_n\;1000)$. In order to control the fluorine contents of the synthesized polyurethanes polytetramethylene glycol (PTMG2000) and $Fluorolink^{(R)}$ were mixed at assigned ratios and reacted with isophorone diisocyanate (IPDI) as a diisocyanate used. Introducing hydrophilic anion to the polymer chain was achieved by applying dimethyl propionic acid (DMPA). The ionic groups were neutralized with triethyl amine (TEA) before dispersion into water. Chain extension was executed by adding ethylene diamine at the final stage. Mechanical properties of the polymers showed that modulus increased with increasing $Fluorolink^{(R)}$ content. Surface energy values obtained from contact angle measurement decreased with increasing $Fluorolink^{(R)}$ content up to $20\%$. We expect that the synthesized polyurethanes present reliable effect from the fluorine atoms incorporated even at a small amount of $Fluorolink^{(R)}$.

• Journal of the Korean Ceramic Society
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• v.31 no.9
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• pp.1076-1086
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• 1994

This study covers synthetic effect of the various hydrothermal treatments on formation of artificially made kaolinite mineral. The hydrothermal treatment includes the temperature treatment with time duration, addition of seeds, particle size of the starting material used, pH variation and the different types of organic acids. A colloidal silica and alumina sol which are commercially available are used for this study. A colloidal silica and alumina sol are mixed by the atomic ratio of Al/Si = 1, based on the theoretical kaolinite composition and calcined at $600^{\circ}C$ for 8 hours duration. It was found that the kaolinitic clay mineral was well developed; thereby, the different patterns of crystalline mineral are appeared. Spherical type as a crystal form was distinctively formed at the temperature of 20$0^{\circ}C$ to 25$0^{\circ}C$ with short duration time, while platy type as a crystal was highly yielded at 300~35$0^{\circ}C$. Moreover, by adding more than 20 wt% of seed as the natural kaolinitic clay to the starting material is widely distributed and developed when 2 ${\mu}{\textrm}{m}$ or less particle size of the starting material is used; also, when they are heat-treated at the temperature of 25$0^{\circ}C$ with 5 hours duration. With respect of the effect of pH variation on formation of the synthetic kaolinite minerals, the crystalline minerals are highly yielded at less than pH 2 and gradually diminished at more than pH9. Regarding to the effect of different acids on development of the kaolinite mineral, the organic acids with high chelating capacity produces good formation of crystalline minerals; whereas, amine radical-(NH2) is not an effective agent to generate the crystalline minerals.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.7
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• pp.1087-1095
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• 2020

Objective: The present study aimed to evaluate the effects of γ-aminobutyric acid (GABA)-producing bacteria (GPB) on in vitro rumen fermentation and on the growth performance and meat quality of Hanwoo steers. Methods: The effects of GPB (Lactobacillus brevis YM 3-30)-produced and commercially available GABA were investigated using in vitro rumen fermentation. Using soybean meal as a substrate, either GPB-produced or commercially available GABA were added to the in vitro rumen fermentation bottles, as follows: control, no additive; T1, 2 g/L GPB; T2, 5 g/L GPB; T3, 2 g/L autoclaved GPB; T4, 5 g/L autoclaved GPB; T5, 2 g/L GABA; and T6, 5 g/L GABA. In addition, 27 Hanwoo steers (602.06±10.13 kg) were subjected to a 129-day feeding trial, during which they were fed daily with a commercially available total mixed ration that was supplemented with different amounts of GPB-produced GABA (control, no additive; T1, 2 g/L GPB; T2, 5 g/L GPB). The degree of marbling was assessed using the nine-point beef marbling standard while endotoxin was analyzed using a Chromo-Limulus amebocyte lysate test. Results: In regard to in vitro rumen fermentation, the addition of GPB-produced GABA failed to significantly affect pH or total gas production but did increase the ammonia nitrogen (NH₃-N) concentration (p<0.05) and reduce total biogenic amines (p<0.05). Animals fed the GPB-produced GABA diet exhibited significantly lower levels of blood endotoxins than control animals and yielded comparable average daily gain, feed conversion ratio, and beef marbling scores. Conclusion: The addition of GPB improved in vitro fermentation by reducing biogenic amine production and by increasing both antioxidant activity and NH₃-N production. Moreover, it also reduced the blood endotoxin levels of Hanwoo steers.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.280-285
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• 2005

The method of chemical absorption has been presented to separate and recover acid gases like $CO_2\;and\;H_2S$. But, this method has some problems such as loss of valuable amine and operational problems (forming, corrosion and fouling) by degradation. In this study, we investigated the degradation characteristics of aqueous AMP solution containing additives such as HMDA, MDEA and piperazine. The degradation was affected by temperature and process time. AMP solution absorbing $CO_2\;and\;H_2S$ was degraded 105% and 23% more than pure AMP at $120^{\circ}C$ respectively. In addition, all the additives were degraded significantly as the temperature increased. The order of the degraded amount of additives mixed in the AMP solution containing absorbed $CO_2$ was as followings : HMDA > piperazine > MDEA.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4265-4269
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• 2011

A method based on ethyl acetate extraction and gas chromatography with tandem mass spectrometry was developed for determining tetraconazole residues in fruits and vegetables. A 10 g homogenized sample was mixed with 10 mL ethyl acetate, shaken vigorously for 3 min, stored at $-20^{\circ}C$ for 15 min, and then vortexed vigorously for 1 min; 1 g NaCl and 4 g anhydrous $MgSO_4$ were added. The clean-up was carried out by applying dispersive solid-phase with 150 mg $MgSO_4$and 50 mg primary secondary amine. Three precursor product ion transitions for tetraconazole were measured and evaluated to provide the maximum degree of confidence. Average recoveries in fruits and vegetables at three levels (0.005, 0.05 and 0.5 mg/kg) ranged from 85.53% to 110.66% with relative standard deviations ($RSD_r$) from 1.3% to 17.5%. The LODs ranged from 0.002 to 0.004 ${\mu}g$/kg, and LOQs ranged from 0.006 to 0.012 ${\mu}g$/kg. This method was also applied to determine tetraconazole residue in cucumber dissipation experiment under field conditions. The half-lives of tetraconazole in cucumber were in the range of 2.1-3.1 days.