• ALGAE
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• v.28 no.1
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• pp.101-109
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• 2013

Some Chlorella species grow heterotrophically with organic substrate in dark condition. However, heterotrophic Chlorella species are limited and their optimum culture conditions are not fully known. In this study, three heterotrophic Chlorella species, two strains (C4-3 and C4-4) of C. vulgaris and one Chlorella sp. (C4-8) were examined on optimum culture conditions such as carbon source, temperature, and concentrations of nitrogen and phosphorus in Jaworski's medium (JM). And the growth and fatty acid composition of Chlorella were analyzed. For three heterotrophic Chlorella species, glucose (1-2%) as a carbon source only increased the growth and the range of optimum culture temperature was $26-28^{\circ}C$. Doubled concentrations of the nitrogen or phosphorus in JM medium also improved the growth of Chlorella. Chlorella cultured heterotrophically showed significantly higher growth rate and bigger cell size than those autotrophically did. C. vulgaris (C4-3) cultured heterotrophically showed the highest biomass in dry weight ($0.8g\;L^{-1}$) among three species. With respect to fatty acid composition, the contents of C16:0 and n-3 highly unsaturated fatty acid (HUFA) were significantly higher in autotrophic Chlorella than in heterotrophic one and those of total lipid were not different between different concentrations of nitrogen and phosphorus in JM medium. Among three Chlorella species in this study, C. vulgaris (C4-3) appeared to be the most ideal heterotrophic Chlorella species for industrial application since it had a high biomass and lipid content.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.1
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• pp.228-236
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• 1997

The browning characteristic and dyeability of the mushroom were examined to establish the optimum condition for browning and extraction in the process of obtaining the natural dye, brown colorant. The composition of browning extracts from mushroom was also analyzed and the dyeability were investigated. The results of this study are as follows, 1. The optimum condition for obtaining the browning colorant from mushroom was the crushed phase of sample. 2. The browning reaction by enzymes in mushroom was efficient at a temperature of 35$^{\circ}C$, a duratron period of 2 hr and pH of 8. 3. The optimum condition for extraction of browning extracts from browned mushroom was at 95$^{\circ}C$ and Ihr. 4. To analyze the content of browning extracts in the mushroom, three fractions were obtained from gel filtration using Sephadex G-25 and the fraction 1 was melanin and the fraction 3 was dihydroxyphenylanine (DOPA) and glutaminyldihydroxybenzene (GDHB) . 5. The turbidity in enzymatic browning extraction of mushroom increased depending on refrigeration storage (4$^{\circ}C$) and UV radiation. The filtration of the extracts resulted in a decrease of absorbance. 6. The dyeability of the fraction 1 was greater compared to that of the fraction 3 and that of wool greater compared to the other two fabric materiales.

• Tribology and Lubricants
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• v.22 no.5
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• pp.269-275
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• 2006

Rolling bearings are classified one of the most important machine elements. The various function of bearings are greatly influenced by grease, and higher performance of rolling bearing greases is required to improve bearing lubrication. Three urea/ether oil greases with different composition were synthesized to compare the performance of these greases. The typical grease physical properties were investigated, and life test of these greases was conducted by FE-9 grease life tester. The grease with higher content of the thickener showed higher performance. After these preliminary test, twelve greases were synthesized and evaluated the performance of dropping point and OIT value. And optimized conditions for grease synthesis were selected by SSRED (Six Sigma Robust Engineering Design) using dropping point and OIT value respectively. The optimized grease using OIT value showed longer grease life than that using dropping point. Two greases were synthesized following the optimum synthesis conditions by means of OIT value. Then grease life and other properties of these greases were investigated. These two greasaes showed longer grease life than typical urea/ether oil grease.

• Journal of environmental and Sanitary engineering
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• v.15 no.3
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• pp.23-23
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• 2000

In this study, to determine the optimum fermentation process for the feed production of food wastes and estimate the practical value of fermented feed using kudzu creeper and sawdust as bulking agent. This study considered initial C/N ratio control as the fermentation process variables. The results are summarized as follows. Minimum water contents of byproducts in the fermentation feed production showed 3994(kudzu), 37%( sawdust) at the C/N ratio 25 and 45%(kudzu, sawdust) at the C/N ratio 35. Temperature variations in the fermentation feed production at the C/n ratio 25 indicated 68'C(kudzu), 70'C (sawdust).Optimum condition of consists of fermentation process of water content, C/N ratio and permeability (porous structure of the mixture). For optimum fermentation of gravitationally, dewatered garbage, the proper mixing ratios of kudzu(moisture contents : 17.3%) and sawdust(moisture contents : 13.2%) were 41% and 39%, respectively Major biological reaction in the aerobic fermentation feed production occurred during 12~14hrs

• Computers and Concrete
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• v.9 no.2
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• pp.119-131
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• 2012

Optimum packing of aggregate is an important aspect of mixture design, since porosity may be reduced and strength improved. It may also cause a reduction in paste content and is thus of economic relevance too. Several mathematic packing models have been developed in the literature for optimization of mixture design. However in this study, numerical simulation will be used as the main tool for this purpose. A basic, simple theoretical model is used for approximate assessment of mixture optimization. Calculation and simulation will start from a bimodal mixture that is based on the mono-sized packing experiences. Tri-modal and multi-sized particle packing will then be discussed to find the optimum mixture. This study will demonstrate that computer simulation is a good alternative for mixture design and optimization when appropriate particle shapes are selected. Although primarily focusing on aggregate, optimization of blends of Portland cement and mineral admixtures could basically be approached in a similar way.

• Journal of Ginseng Research
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• v.3 no.2
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• pp.156-167
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• 1979

Physiological characteristics of Panax ginseng were reviewed in relation to temperature. According to the old literatures and records of cultivator's experiences it was elucidated that ginseng plants require light but hate high temperature and that the cultural methods were developed to content two characteristics in contradiction. Low temperature (cool climate) during growing season seems (or ginseng to be essential and to escape from the extreme coldness according to air and soil temperature of natural habitat and cultivated area. Optimum temperature of dehiscence (15∼below 20$^{\circ}C$) is a little higher than that of germination (10∼15$^{\circ}C$). Optimum temperature for growing of new buds (18∼20$^{\circ}C$) is similar to that for growing after emergence (17∼21$^{\circ}C$). Dormancy of both matured embryo and new buds is broken at the same temperature (2∼3$^{\circ}C$). It seems reasonable that optimum temperature of photosynthesis (22$^{\circ}C$) is similar to that of growth. Respiration quotients of various organs or of whole plant ranged from 1.7 to 3 incrased with high temperature. Respiratory consumption and oxygen limitation seem to be potential factors to induce decay during dehiscence and germination of seeds and root rot in fields. Research on organ differentiation. photosynthesis, respiration and growth with age is needed for the development of cultivation methods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.5
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• pp.381-388
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• 2004

In Korea, production of super sweet corn has been economically feasible and is substituting for traditional sweet corn due to better flavor in recent years. Major limiting factors for super sweet corn production are low field emergence and low seedling vigor. The optimum water potential (WP) for the priming of normal and aged seeds of dent, sweet (su) and super sweet (sh2) corns was studied to improve low seed quality. Seeds were primed at 0, -0.3, -0.6, -0.9, and -1.2 MPa of polyethylene glycol (PEG) 8000 solution at $15^{\circ}C$ for 2 days. Priming effects differed depending on the type of corn, seed quality, and WP of PEG solution. Although WP of priming solution did not influence the emergence rate of extremely high quality normal dent corn seeds, it reduced time to $50\%$ emergence (T50) and increased plumule weight. In contrast, the emergence rate of aged field corn was improved by seed priming at 0 MPa and plumule weight and $\alpha-amylase$ activity was enhanced. The optimum WP for both normal and aged sweet and super sweet corn seeds was between -0.3 and -0.6 Mpa. At the optimum WP emergence rate, $\alpha-amylase$ activity, and content of DNA and soluble protein increased, while T50 and leakage of total sugars and electrolytes reduced.

• Preventive Nutrition and Food Science
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• v.11 no.2
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• pp.166-170
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• 2006

This study was carried out to investigate the fermentation characteristics and optimum conditions for alcohol fermentation of the Korean native mulberry. The yeast strains of S. kluyveri DJ97, La parisienne (Saccharomyces cerevisiae, Netherlands) and Enoferm (Saccharomyces cerevisiae, Denmark) produced higher alcohol concentrations than other strains, and further study was therefore performed with these three species. The optimum additional water content for maximizing alcohol concentration was 250% (v/w). The alcohol concentrations were rapidly increased in the first 4 days under the optimum conditions and reached 13.8% for S. kluyveri DJ97, 14.0% for La parisienne and 14.0% for Enoferm, respectively. Residual sugar concentration was decreased steadily from the beginning of fermentation until 5 days, after which it maintained a constant level. The pH was decreased steadily in the log phase during further maturation. However, the pH underwent a slight decrease after 4 days and then was stabilized during further maturation. Methanol concentrations for the three species used were analyzed after 60 days maturation and were lower than the levels regulated by the food standard. Fusel oils such as n-propanol, iso-butanol, and iso-amyl-alcohol were produced as by-products with the highest production from Enoferm and the lowest from S. kluyveri DJ97.

• Microbiology and Biotechnology Letters
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• v.41 no.3
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• pp.278-283
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• 2013

A gram-positive, rod-shaped, spore-forming, motile thermophilic bacterium was isolated from a sterilization oven. The microorganism GWE1, formally named Geobacillus wiegelii identified as a member of the genus Geobacillus. GWE1 grew under aerobic conditions of between $60-80^{\circ}C$ (optimum $670^{\circ}C$), in a pH range of 3.0-8.0 (optimum $pH^{70^{\circ}C}$ 5.8), and between 0 and 2 M NaCl (optimum 0.3 M). The membrane polar lipids were dominated by branched saturated fatty acids, which included as the major constituents; iso-15:0 (13.3%), 16:1(${\omega}7$) (12.8%), 16:0 (28.5%), iso-17:0 (13.5%) and anteiso-17:0 (12.3%). The DNA G+C content was 47.2 mol% (determined by HPLC). The 16S rRNA gene sequence of GWE1 showed a high similarity with Geobacillus caldoxylosilyticus (97%). However, the level of DNA-DNA relatedness was only 58%. These data suggest that GWE1 is probably a novel specie of the genus Geobacillus.

• Applied Biological Chemistry
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• v.35 no.1
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• pp.64-67
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• 1992

To extract insoluble proteins of soymilk residue by microorganism, the soymilk residue was treated with crude enzyme solution from Aspergillus oryzae. Optimum conditions of pH, temperature and digestion time were determined, and amino acid composition of the extract was analyzed. The optimum pH for the extraction was 7.5, and the maximum extraction was obtained at $50^{\circ}C$. Under optimum conditions, the extractability with Koji reached to 70% in 12 hrs. The content of essential amino acids of extract was generally high and the composition of essential amino acid was good.