• 한국염색가공학회지
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• 제14권4호
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• pp.240-248
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• 2002

The most effective solvent for extract of dye from amur cork tree was methanol. Two protoberberine alkaloids, berberine and palmatine, were isolated from amur cork tree by Prep-TLC, and the developing solvent was Benzene : AcOEt ; PrOH ; MeOH ; EtNH$_2$(8: 4: 2: 0.5: 0.5). Dyes were stable at a high temperature and there wasn't any change of color at pH 3~9 and with added metal mordants. In adsorption spectra of aqueous solution of berberine and tannin mixture, two isosbestic points$(328^{nm},\;357^{nm})$ were found and the mole fraction of reaction of components was 1:1.

• 한국식품저장유통학회지
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• 제7권2호
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• pp.195-200
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• 2000

Yields of various solvent extracts for Zanthoxylum schinifolium and Z. piperitum leaves were higher in ethanol extract layer. Ethanol Extract in sancho and chopi leaves was fractionated with different solvents, such as hexane, chloroform, ethyl acetate, butanol and water, yields of hexane fraction was higher. In the solvent extracts using methanol, ethanol, hexane, chloroform, and water, ethanol extract showed the most effective antimicrobial activities. Ethanol extract in sancho and chopi leaves was fractionated, the most antimicrobial activities of sancho leaf were ethyl acetate fraction, and chopi leaf were chloroform fraction.

• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2212-2216
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• 2011

An ionic liquid-based ultrasonic-assisted extraction method has been successfully applied to the effective extraction of phenolic compounds from Laminaria japonica Aresch. Three kinds of 1-alkyl-3-methyl-imidazolium with different cations and anions were evaluated for extraction efficiency. The results showed that both the characteristics of anions and cations have remarkable effects on the extraction efficiency. In addition, the ionic liquid-based ultrasonic-assisted extraction procedure was also optimized on some extraction parameters, such as ultrasonic power, extraction time and solid-liquid ratio. Compared with the conventional solvent, the optimum approach gained the highest extraction efficiency within the shortest extraction time. Average recoveries of phenolic compounds were from 75.5% to 88.3% at three concentration levels.

• KSBB Journal
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• 제13권2호
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• pp.133-140
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• 1998

Using rlFN-$\alpha$ and rhGH as the model proteins, the refolding performances of the published processes were evaluated and compared. Key engineering parameters such as the type of denaturant and this concentration, protein concentration in the refolding buffer, and pH and ionic strength of the buffer were experimentally investigated. Furthermore, the role of a co-solvent of surfactant type in aggregation reduction was also studied. Of the denaturants tested (8M urea, 6M guanidine HCI, 0.5% SDS), SDS at alkaline pH (9.5) and ambient temperature gave the highest recovery yield. The SDS process was effective in the refolding of observed where dissolution proceeded better under lower strength (10 mM) but aggregation was suppressed under higher strength (>50 mM.) When PEG-4000 and/or Tween were added as co-solvent or refolding-enhancing additive, 1.6-2 times higher yield was realized. The‘masking’of the hyrophobic patches located on the surface of the protein with the surfactant molecules was believed to be responsible for the considerable reduction in aggregation during refolding.

• 한국세라믹학회지
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• 제32권5호
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• pp.559-566
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• 1995

Alumina powder was coated with stearic acid and then mixed with isotactic polypropylene, atactic polypropylene as binders at 15$0^{\circ}C$ for 2 hours. The mixture was then injection molded at various mold temperatures using injection molding machine to investigate the effect of the molding temperature and debinding parameters on the formation of the defects. The molded specimens were debinded in both air and nitrogen atmospheres. Wicking and solvent methods were also used to enhance debinding efficiency. The specimens were prefired at 120$0^{\circ}C$ and then sintered at 150$0^{\circ}C$ for 3 hours. Various defects were formed at mold temoperature of 3$0^{\circ}C$, 6$0^{\circ}C$ and 10$0^{\circ}C$ and any noticeable defect was not formed at 85$^{\circ}C$. The density of green body increased with mold temperature. Debinding in air atmosphere was more effective than in nitrogen atmosphere. Results also proved that wicking and solvent treatments helped minimize the number of defects.

• 한국응용과학기술학회지
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• 제13권1호
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• pp.47-54
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• 1996

Cinnamoyl ester(PGEFC) of poly(phloroglucinol-formaldehyde) glycidyl ether which has photosensitive functional group was prepared to apply to photoresist. Photosensitivity of PGEFC was estimated by the solubility difference in organic solvent before and after exposure to light. The yield of residual film was calculated by immersing the sample-coated quartz plates in the solvent which was used in coating. The yield of the residual film which was closely related to the sensitivity of the film, was affected by the degree of polymerization of the backbone resin, sensitizers and their concentration. The sensitivity was depended upon the degree of polymerization. Most of effective sensitizer for PGEFC among the sensitizers was 2, 6-dichloro-4-nitroaniline.

• 한국식품영양과학회지
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• 제29권2호
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• pp.329-334
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• 2000

Two major oleananesaponins in Bupleuri radix, saikosaponin $\alpha$ and d, were extracted at various solvent compositions and leaching temperatures. Solvent composition was varied at 0 to 100%(v/v) of ethanol-water and methanol-water, whereas leaching temperature was adjusted to te range of 25~45$^{\circ}C$. The most effective extractant and leaching temperature were 70% ethanol and 45$^{\circ}C$, respectively. However, no major differences in saikosaponin content and cAMP phosphodiesterase inhibition were found at various leaching times. The cAMP phosphodiesterase inhibitions were alo the highest when 70% ethanol was used as the extractant.

• 한국광학회:학술대회논문집
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• 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.13-19
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• 1989

Passive mode-locking of a pulsed Nd:YAG laser is achieved with saturable absorbers, BDN dye in iodoethane solvent and Kodak Eastman # 26 dye in 1,2-dichloroethane solvent, and its optimum conditions are investigated. The thickness of saturable absorbers employed in the laser mode-locking is 0.16~0.50mm. The PBR (peak-to-background ratio) measured in the oscilloscope is 79.8% in Kodak Eastman # 26 dye at the neighbourhood of the peak power, whereas the passive mode-locking with BDN dye gives PBR of 67.7%. BDN and Kodak Eastman # 26 dyes are superior in photostability over Kodak eastman # 9860 and # 9740 dyes which were used previously in passive mode-locking. From the PBR curve, we find that Kodak Eastman # 26dye is more effective than BDN dye in passive mode-locking. The spacing between the adjacent pulses of the pulse train, which depends on the laser cavity length, is measured and is found to be 7 nsec for the cavity length of 100cm.

• 분석과학
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• 제34권4호
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• pp.180-190
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• 2021

This study compared the efficacy of chiral GC and chiral HPLC for the analysis of nicotine. To develop a suitable dispersive liquid-liquid microextraction (DLLME) method, the following parameters were optimized: pH, extraction solvent, dispersive solvent, type and quantity of salt, and laboratory temperature. The validation of the method was carried out by the established HPLC method. The LODs were 0.11 ㎍/mL and 0.17 ㎍/mL for the (S)- and (R)- enantiomers, respectively. The LOQs were 0.30 ㎍/mL and 0.44 ㎍/mL, respectively. The optimal calibration range was between 0.30-18 ㎍/mL and 0.44-4.40 ㎍/mL, respectively, and the correlation coefficient (r²) was 0.9978-0.9996. The intra-day accuracy was 79.9-110.6 %, and the intra-day precision was 1.3-12.0 %. The inter-day accuracy was 87.8-108.0 %, and the inter-day precision was 4.0-12.8 %. E-liquid and biological fluids (urine and saliva) were analyzed using the established method.

• Journal of Microbiology and Biotechnology
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• 제25권5호
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• pp.718-722
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• 2015

Techniques for immobilizing effective enzymes on nanoparticles for stabilization of the activity of free enzymes have been developing as a pharmaceutical field. In this study, we examined the effect of three different pH conditions of phosphate buffer, as a dissolving solvent for lysosomal enzymes, on the direct immobilization of lysosomal enzymes extracted from Hen's egg white and Saccharomyces cerevisiae. Titanium(IV) oxide (TiO₂) nanoparticles, which are extensively used in many research fields, were used in this study. The lysosomal enzymes immobilized on TiO₂ under each pH condition were evaluated to maintain the specific activity of lysosomal enzymes, so that we can determine the degree of melanin treatment in lysosomal enzymes immobilized on TiO₂. We found that the immobilization efficiency and melanin treatment activity in both lysosomal enzymes extracted from Hen's egg white and S. cerevisiae were the highest in an acidic condition of phosphate buffer (pH 4). However, the immobilization efficiency and melanin treatment activity were inversely proportional to the increase in pH under alkaline conditions. In addition, enhanced immobilization efficiency was shown in TiO₂ pretreated with a divalent, positively charged ion, Ca²⁺, and the melanin treatment activity of immobilized lysosomal enzymes on TiO₂ pretreated with Ca²⁺ was also increased. Therefore, this result suggests that the immobilization efficiency and melanin treatment activity of lysosomal enzymes can be enhanced according to the pH conditions of the dissolving solvent.