• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.207-210
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• 2002

PVDF는 측쇄에 C=O기를 갖는 고분자인 PMMA와 PVAc와의 블렌드 및 주쇄에 C=O기를 갖는 poly(1,4-butylene adipate) (PBA)와의 블렌드에서 PVDF의 융점보다 상당히 높은 온도에서 LCST거동을 보이고 있음이 알려져 있다. 그런데 PVDF/PMMA와 PVDF/PVAC 블렌드계에서는 LCST가 고분자의 열분해온도와 유사하여 LCST거동을 실험적으로 관찰하기 어려웠다. 그런데 PVDF/PBA 블렌드계에서는 실험적으로 측정할 수 있을 정도로 LCST가 낮아지긴 하였지만 PBA의 열분해를 완전히 배제하기엔 아직도 높은 온도이다.[1] (중략)

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.32-32
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• 2003

Calcuim borate 화합물의 하나인 Colemanite 천연원광을 출발물질로 붕산을 제조하는 공정에 대한 연구로 황산 첨가량과 처리온도, 건조온도와 시간에 따라 생성되는 붕산의 결정상과 수득률, 순도 및 입자의 형상을 관찰하였다. 황산 첨가로 붕소 성분은 용해되어 액상에 남고, SO$_4$$^{2-}$ 와 결합하여 불용성 고체로 분리되고, 붕소의 온도에 따른 용해도 차를 이용하여 재결정화하는 방법으로 99% 이상의 순도를 갖는 붕산(H$_3$BO$_3$)을 얻었다. 공정의 각 단계에서 생성되는 화합물을 TG, NMR, IR, XRD, ICP 등의 방법으로 분석하여 최적 제조 조건을 찾았다.

• The Korean Journal of Food And Nutrition
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• v.19 no.4
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• pp.496-501
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• 2006

This study was to isolate a bacterium producing a alkaline protease from mud flats of the west seaside of Korea and to investigate the biochemical analysis of the alkaline protease producing from the isolate. The isolate was named as Gelidibacter sp. HK-1 based on 16S rRNA sequence, Gram staining and the photograph of electron microsceope. Optimum temperature for growth and pretense production of the isolate was $25^{\circ}C$. Growth of the isolate was reached at stationary phase after 10hrs followed by inoculation. Maximum activity of protease produced from the isolate was shown after 14hrs. Optimum temperature and pH for the protease activity were $45^{\circ}C$ and pH 9, respectively. Molecular weight of the pretense was about 50KD and the partial amino acid sequence of the pretense was Ala-Try-Ala-Leu-Asn-Thr-Ser-Val-Thr-Glu-Thr-Phe-Ala-Lys. The partial amino acid sequences of the protease showed significant homology with a pretense produced from Streptomyces avermitilis.

• Membrane Journal
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• v.27 no.2
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• pp.189-198
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• 2017

In this study, we used thermally induced phase separation (TIPS) to produce water treatment membrane and poly(vinylidene fluoride) (PVDF), silica with excellent mechanical properties and chemical resistance to evaluate characterization of the membrane. The diluents used for the characterization were dioctyl phthalate (DOP) and dibutyl phthalate (DBP). We observed the crystallization temperature, cloud point and SEM images to see the manufacture conditions according to the ratio of PVDF and silica. The crystallization temperature and cloud point increased with the contents of silica. Through the phase diagram drawn from these results, the conditions for the preparation of the membrane confirmed.

• Clean Technology
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• v.18 no.4
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• pp.360-365
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• 2012

With rapid increase in municipal solid waste (MSW) due to the rising economy, solid waste gasification emerges as one of the promising technologies. Separation of the carbon monoxide (CO) and hydrogen ($H_2$) from syngas obtained by gasification of MSW was studied using the polyamide composite membrane. The separation characteristics of the CO and $H_2$ were studied at different gas flow rates and stage cuts. The permeability of CO and $H_2$ along with the selectivity of $H_2$ with respect to CO was obtained. Furthermore, the Arrhenius plots were obtained to estimate the activation energies of CO and $H_2$ permeabilites.

• Korean Journal of Microbiology
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• v.45 no.1
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• pp.58-62
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• 2009

From the course of screening of useful enzyme producing microorganism from marine sedimentary layer, we isolated 2 lipase producing strains and their lipase producing activities were tested. 16S rDNA sequence analysis showed that they were Gram-positive bacteria grouped on Janibacter sp. An excellent lipase producing strain, Janibacter sp. LI-68 and J. sp. LI-80 identified by 16S rDNA analysis and biochemical methods (BIOLOG), was further studied its lipase producing characteristics. The optimum initial pH, temperature and the optimum cultral time for the enzyme production on MA medium were 8, $30{\sim}40^{\circ}C$ and 96 h, respectively.

• Journal of the Korean Chemical Society
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• v.37 no.12
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• pp.1035-1046
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• 1993

Some iron(III)porphyrin complexes were prepared, and identified by the spectroscopic methods. Elution behavior of iron(III)porphyrin complexes was investigated by reversed-phase HPLC. The optimum conditions for the separation of iron(III)porphyrin complexes were examined with respect to flow rate and mobile phase strength. These complexes were successfully separated on NOVA-PAK $C_{18}$ column using methanol / water(95/5) for $[T_pCF_3PP)Fe(R)]$ and methanol / water (98/2) for $[(P)Fe(C_6F_5)]$ as a mobile phase. It was found that these complexes were largely eluted in an acceptable range of capacity factor value ($0{\leq}logk'{\leq}1$). The dependence of the capacity factor (k') on the volume fraction of water in the binary mobile phase as well as the dependence of k' on the liquid-liquid extraction distribution ratio$(D_c)$ in methanol-water / n-pentadecane extraction system showed a good linearity. It means that the retention of iron(III)porphyrin complexes on NOVA-PAK $C_{18}$ column is largely due to the solvophobic effect. Also, there was a good linear dependence of the capacity factor(k') on the column temperature and enthalpy calculated by van't Hoff plot. From these results, it was confirmed that the retention mechanism of iron(III)porphyrin complexes in reversed-phase liquid chromatography was invariant under the condition of various temperature, and the solvophobic binding process exhibited isoequilibrium behavior.

• Membrane Journal
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• v.32 no.2
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• pp.140-149
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• 2022

In this study, the conditions of low temperature and high pressure of biogas upgrading process using polysulfone membrane have been designed and tested to achieve the high recovery and efficiency corresponding to those of the highly selective polymeric materials. Polysulfone hollow fiber membrane with 4-component dope solution was spun via non-solvent induced phase separation. The hollow fiber membrane was mounted into a 1.5 inch housing. The effective area was 1.6 m², and its performance was examined in various operation temperatures and pressures. CO₂ and CH₄ permeances were 412 and 12.7 GPU at 20℃, and 280 and 3.6 GPU at -20℃, respectively, while the CO₂/CH₄ selectivity increased from 32.4 to 77.8. Single gas test was followed by the mixed gas experiments using single-stage and double stage where the membrane area ratio varied from 1:1 to 1:3. At the single-stage, CH₄ purity increased and the recovery decreased as the stage-cut increased. At the double stage, the area ratio of 1:3 showed the higher CH₄ recovery as decreasing the operation temperature at the same purity of CH₄ 97%. Finally, polysulfone hollow fiber membranes have yielded of both CH₄ purity and recovery of 97% at -20℃ and 16 barg.

• Membrane Journal
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• v.20 no.3
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• pp.249-258
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• 2010

In this study, we tried to observe the permeation on the single $O_2$, $CF_4$ and $SF_6$ gas using a PSF (polysulfone), PC (tetra-bromo polycarbonate) and PI (polyimide) hollow fiber membranes. We also observed the permselectivity on the $O_2/SF_6$ and $CF_4/SF_6$. According to the results of single gases permeation for different pressures, PSF membrane has the highest $O_2$ permeation of 37.5 GPU and PC membrane has the highest $SF_6$ permeation of 2.7 GPU and the highest $CF_4$ permeation of 2.5 GPU at 1.1 MPa. According to the results of single gases permeation for different temperatures, PSF membrane has the highest permeation of $O_2$ at $45^{\circ}C$ and PC membrane has the highest permeation of $SF_6$ and $CF_4$ at $25^{\circ}C$. From the result of $O_2/SF_6$ and $CF_4/SF_6$ permselectivity for different pressures and temperature, the highest permeation and the lowest permselectivity were observed in the PSF and PC membrane. On the contrary, the lowest permeation and the highest permselectivity was observed in the PI membrane.

• Journal of Applied Biological Chemistry
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• v.54 no.2
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• pp.94-100
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• 2011

A gene encoding a putative phospholipase D was isolated from Bacillus licheniformis and cloned into pGEM-T easy vector. The gene was expressed in E. coli BL21 (DE3) using a pET-21(a) vector containing His6 tag. Affinity purification of the recombinant phospholipase D with nickel-nitrilotriacetic acid (Ni-NTA) resin resulted major one-band by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The purified enzyme showed a molecular weight of 44 kDa. The optimum activity of enzyme was around pH 7.0 and the enzyme was also the most stable around this condition. The optimum temperature was about $40-45^{\circ}C$ and the enzyme still showed considerable activities at wide range of temperature. Among various detergents, Triton X-100 significantly increased the enzyme activity, resulting in 181% activity of control at 0.6 mM of the detergent. Calcium ion did not significantly affect the enzyme activity, suggesting that the enzyme might be classified into $Ca^{2+}$-independent PLD.