• Food Science and Preservation
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• v.4 no.2
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• pp.131-137
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• 1997

Effect of storage on the tree and quality of early cultivar of Citrus unshiu Marc. produced in Cheju according to harvest time were investigated. Soluble solids, acid content, flesh ratio, firmness and specific cavity of the fruits harvested at 27th of November were 12.0, 1.03%, 79.98%, 0.774kg-force, 0.912, respectively. Soluble solids, total sugar and reducing sugar were increased gradually, but acid content was decreased slightly as delayed in harvest time. Otherwise specific gravity and firmness were not shown in great during harvest time, color index(a/b) was increased sharply till late November and then remained in stationary phase. On these result, we recommend that the harvest time of early cultivar of Citrus unshiu Marc. would be during December because of wilting partly. Fully ripened-fruits harvested late, compared to ordinary harvest time, with cold storage would be kept more quality and freshness of fruits for fresh consumption than the fruits harvested early and stored at room temperature.

• KSBB Journal
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• v.15 no.6
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• pp.541-547
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• 2000

Simulated moving bed (SMB) chromatography has been investigated in order to separate chiral compounds for pharmaceutical use. SMB utilizes the principle of true moving bed (TMB) chromatography, and has the advantages of low solvent usage, flexible configuration of columns and hardwares, and high productivity of the chiral compounds over the TMB. Large scale separation of xylene isomers and saccharides has been conducted since 1960s. However, the application of SMB in the fine chemical industries is still in the infant stage. The study of SMB for the chiral compounds production was initiated in the mid 1990s and further researches are actively undergoing. This review summarizes the principle of SMB as well as the chemistry of chiral stationary phase and chiral compounds.

• KSBB Journal
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• v.9 no.2
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• pp.98-103
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• 1994

A bed configuration wherein sheets of modified fibrous polyethylene are potted within a Millipore Filter Cartridge matrix has been developed. Polyethylene fibers form sturdy beds but the native hydrophobicity and inertness of polyethylene have precluded their use in protein chromatography The polyethylene fibers used in this system were modified by plasma oxidation and further derivatization. The resulting fibers are hydrophilic, bind protein reversibly and serve as an anion-exchange stationary phase. Separation of Bovine Serum Albumin on this bed, as well as results of basic studies on capacity and reversibility of binding within a fibrous bed and experimental data handling system are shown.

• Journal of Industrial Technology
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• v.1
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• pp.61-66
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• 1981

In order to use as a starter after drying, optimum growth conditions of Str. thermophilus and L. bulgaricus were investigated. The results were as follows. The growth of Str. thermophilus was reached at stationary phase after 12 hours incubation and L. bulgaricus was after 6 hours. Str. thermophilus was grown well, in the medium containing 10% of skim milk, 2% of sucrose, 0.1% of KCl and 0.015% (v./v.) of soy-sauce. In the case of L. bulgaricus, 10% of skim milk, 2% of glucose, 0.5% of bacto-peptone, 0.1% of $K_2HPO_4$ and 0.02% of pyridoxine was suitable for the maximum growth.

• Bulletin of the Korean Chemical Society
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• v.24 no.5
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• pp.555-558
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• 2003

An enrichment/separation system for atomic absorption spectrometric determinations of Cu(Ⅱ), Fe(Ⅲ), Ni(Ⅱ) and Co(Ⅱ) has been established. The procedure is based on the adsorption of the analytes as calmagite chelates on Chromosorb-102. The effects of some parameters including pH, amount of ligand, salt matrix, flow rates of sample and eluent solutions were investigated. Under optimized conditions, the relative standard deviation of the combined method of sample treatment, preconcentration and determination with FAAS (N=5) is generally lower than 5%. The limit of detection (3σ) was between 6.0-112.9 ㎍/L. The results were used for preconcentration of analytes from some sodium and ammonium salt.

• Bulletin of the Korean Chemical Society
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• v.27 no.1
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• pp.71-76
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• 2006

Porous polymer monolithic columns were prepared by the direct free radical copolymerization of methacrylic acid and ethylene glycol dimethacrylate within the confines of a chromatographic column in the presence of toluene-dodecanol as a porogenic solvent. The separation characteristics of the monolithic columns were tested by a homologous series of xanthine derivatives, theophylline and caffeine. The effects of the polymerization mixture composition and polymerization condition, mobile phase composition, flow rate and temperature on the retention times and separation efficiencies were investigated. The results showed that the selection of correct porogenic solvents and appropriate polymerization conditions are crucial for the preparation of the monolithic stationary phases. The separation efficiency was only extremely weakly dependent on flow rate and temperatures. Hydrogen-bonding interaction played an important role in the retention and separation. Compared with conventional particle columns, the monolithic column exhibited good stability, ease of regeneration, high separation efficiency and fast analysis.

• Archives of Pharmacal Research
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• v.16 no.4
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• pp.300-304
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• 1993

Genetic transformation of streptomyces gaespitosus by plasmid plJ 702 was camied out. Optimal conditions for the protoplast preparation of streptomyces casepitosus, its regeneration, and its transformation by plJ 702 were evaluated. Addition of 2% glycine to the culture broth was optimal for protoplast yield. Formation and regeneration of protoplasts were most efficient when the mycelium were harvested at between late log and stationary growth phase. The regeneration frequency of the protoplasts was 15% when the protoplats were regenerated on R2YE agar media containing 0.5M sucrose. Under the best condition for protoplats (M.W. 4,000) treatment for 2 minutes.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.55-60
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• 1998

Various Saccharomyces cerevisiae strains were transformed with a 2 ${\mu}$-based multicopy expression plasmid, pYIGP, carrying Kluyveromyces marxianus inulinase gene under the control of GAPDH promoter. Among then two strains, SEY2102 and 2805, showed high levels of cell growth and inulinase expression, and were selected to study their fermentation properties on inulin. Jerusalem artichoke inulin was more effective for cell growth (10∼11 g-dry wt./L at 48 hr) and inulinase expression (1.0 units/mL with SEY2102/pYIGP and 2.5 units/mL with 2805/pYIGP) than other inulin sources such as dahlia and chicory. It was also found that maximal ethanol production of 9 g/L was obtained from Jerusalem artichoke inulin at the early stationary phase (around 30 hr), indicating that recombinant S. cerevisiae cells secreting exoinulinase could be used for the simultaneous saccharification of inulin and ethanol fermentation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1073-1077
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• 2001

The objective of this paper is to apply an experimental method based on the principle of reciprocity to measuring the structural intensity. Since only one accelerometer is used in this method it has the advantages of shortening measurement time. reducing accelerometer phase error. overcoming the limitation that the situation should be stationary during the experiment. It has been used to measure the vibration intensity of an infinite beam (beam with damped ends) and a semi-infinite beam (beam with simply supported and damped ends). Results showed that the experiment method based on the principle of reciprocity can be effectively used to measure the structural intensity.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.143-144
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• 2016

The circulating current control within the phase legs is one of the main control objectives in a modular multilevel converter (MMC) under different operating conditions. This paper proposes a control strategy of circulating currents in the MMC under unbalanced voltage by using a proportional-resonant (PR) controller. Under the unbalanced voltage, the circulating currents in the MMC consists of three components such as positive-sequence, negative-sequence, and zero-sequence circulating currents. With the PR controller, all components of the circulating current will be directly controlled in the stationary reference frame without decomposing into positive- and negative-sequence components. Thus, the ripples in the circulating currents and the DC current are suppressed under the unbalanced voltage. The effectiveness of the proposed method is verified by simulation results based on PSCAD/EMTDC simulation program.