• Korean Journal of Clinical Laboratory Science
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• v.48 no.4
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• pp.355-364
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• 2016

This study was initiated to evaluate the antioxidant and antimicrobial activities of methanol extract (ME) and hot water extract (HWE) obtained from the fruiting bodies of medicinal mushroom, Phellinus gilvus. The free radical scavenging activity of ME from P. gilvus on 1,1-diphenyl-2-picrylhydrazyl (DPPH) were 93.65% at 2 mg/mL, which was comparable with the positive control, butylated hydroxytoluene (BHT, 96.97%) at the same concentration. The ferrous ion-chelating ability of ME and HWE was significantly higher than that of BHT at all concentration levels. The antimicrobial assay of ME was performed against six bacteria and one species of fungus. ME exhibited antibacterial activity against 5 out of 6 bacteria: Staphylococcus aureus, Streptococcus mutans, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa; whereas, ME did not show antimicrobial activity against gram-negative bacterium Vibrio vulnificus and fungal species Candida albicans. The minimum inhibitory concentration (MIC) of ME against 5 strains of bacteria, such as S. aureus, S. mutans, B. subtilis, E. coli, and P. aeruginosa, was 100, 100, 50, 100, 200 mg/mL, respectively. The results suggest that good antioxidant and microbial activities of P. gilvus fruiting bodies might be used for natural antioxidant and antimicrobial agents.

• Journal of the Korean Electrochemical Society
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• v.9 no.1
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• pp.1-5
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• 2006

Lithium titanium oxide $(Li_4Ti_5O_{12})$ with spinel-framework structures as anode material for lithium-ion battery was prepared by sol-gel and high energy ball milling (HEBH) method. According to the X-ray diffraction (XRD), Particle Size Analyses(PSA) and scanning electron microscopy (SEM) analysis, uniformly distributed $Li_4Ti_5O_{12}$ particles with grain sizes of 100 nm were observed. Half cells, consisting of $Li_4Ti_5O_{12}$ as working electrode and lithium foil as both counter and reference electrodes showed the high performance of high rate discharge capacity and 173 mAh/g at 0.2C in the range of $1.0\sim2.5 V$. Furthermore, the crystalline structure of $Li_4Ti_5O_{12}$ didn't transform during the lithium intercalation and deintercalation process.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.1
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• pp.11-14
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• 2012

The AlGaN layer has direct wide bandgaps ranging from 3.4 to 6.2 eV. Nowadays, it is becoming more important to fabricate optical devices in an UV region for the many applications. The high quality AlGaN layer is necessary to establish the UV optical devices. However, the growth of AlGaN layer on GaN layer is difficult due to the lattice mismatch and difference thermal expansion coefficient between GaN layer and AlGaN layer. In this paper, we attempted to grow the LED structure on GaN template by mixed-source HVPE method with multi-sliding boat system. We tried to find the optical and lattice transition of active layer by control the Al content in mixed-source. For the growth of epi layer, the HCl and $NH_3$ gas were flowed over the mixed-source and the carrier gas was $N_2$. The temperature of source zone and growth zone was stabled at 900 and $1090^{\circ}C$, respectively. After the growth, we performed the x-ray diffraction (XRD) and electro luminescence (EL) measurement.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.2
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• pp.85-90
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• 1978

In present study, the effect of various factors including the solvent concentration, extraction time, extraction temperature and the ratio of sample vs extraction solvent(w/v) upon the extractability of the NaOH soluble proteins of marine algae were investigated. Seven species of sun-dried algae, the major ones in consumption as food, namely Porphyra suborbiculata, Undaria pinnatifida(natural and cultivated), Sargassum fulvellum, Sargassum kjellmanianum, Ulva pertusa, Enteromorpha linza and Codium coarctatum were used for the extraction of the NaOH soluble protein. The frozen and masceratd samples were prepared by the same mettled described in previous paper(Lee, 1977). In case of the TCA insoluble protein, all samples reached maxima at 0.025M NaOH solution while the 0.05M for extractable total nitrogen. Variation of the ratio of sample vs solvent gave slight effect upon the extractability, 100 ml solvent added to 1 g dried sample was effective. The effect of extraction time on the extractability differed from species. The extractabilty of Enteromorpha linza, Ulva pertusa and Codium coarctatum reached maxima within 1 hour extraction and 2 hours for the cultivated Undaria pinnatifida while 3 flours for the natural Undaria pinnatifida, Sargassum fulvellum, Sargassum kjellmanianum and Porphyra suborbiculata. The most effective extraction temperature was $60^{\circ}C$ for all samples.

• Korean Journal of Food Science and Technology
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• v.23 no.5
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• pp.587-592
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• 1991

The curd yogurt was prepared from milk or milk added with skim milk powder or four types of rice powder. Acid production by lactic acid bacteria in milk containing additive of 2% (w/v) was investigated and quality of curd yogurt (sensory property and keeping quality) was examined. Some organic acids in curd yogurt were analyzed by HPLC. Four types of rice powder, particularly brown rice, stimulated acid production by lactic acid bacteria more than control (milk yogurt). Among four organisms tested, Leuconostoc mesenteroides and Lactobacillus bulgaricus produced more acid than L. casei and L. delbrueckii. HPLC analysis of organic acids in curd yogurt showed that the amount of lactic acid markedly increased during the fermentation by L. bulgaricus for 24 hours while the amount of citric acid markedly decreased. Addition of rice powders to milk slightly reduced sensory property of curd yogurt. Among four types of rice powder tested, tongil rice added sample showed better sensory acceptability than other samples. When curd yogurt was kept at $5^{\circ}C$ for two weeks, acidity and number of viable cells of curd yogurt were not changed.

• Korean Journal of Materials Research
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• v.10 no.2
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• pp.117-123
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• 2000

In this study, to fabricate the semi-solid Al alloy, the 3phase-2poles electromagnetic stirring system was adopted. The changes of primary grain size, aspect ratio, standard deviation, hardness and the size morphology of eutectic Si with pouring temperatures and input voltages were investigated. At the same pouring temperature, with increasing input voltage, aspect ratio, standard deviation and primary grain size were decreased. The optimum condition for fabrication of semisolid Al alloys by EMS horizontal continuous casting process was determined that the input voltage was 220V and the pouring temperature was 68$0^{\circ}C$. At this optimum conditions the primary grain size was 54$\mu\textrm{m}$, the aspect ratio was 1.56 and the size of eutectic Si was 0.5$\mu\textrm{m}$. The micro-hardness of the Al alloy was 72.1 Hv. The semi-solid A356 Al alloy which has very low aspect ratio and standard deviation value could be fabricated by adopting the EMS horizontal continuous casting facility that was manufactured for this study.

• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.405-413
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• 2000

This study was conducted to develop an on-line monitoring system for a forest hydrological environment and its meteorological condition, such as temperature, wind direction and speed, rainfall and water level on V-notch, electrical conductivity(EC), potential of hydrogen(PH) by the motor drive sensor unit and measurement with a single-chip microprocessor as controller. These results are summarized as follows ; 1. The monitoring system consists of a signal process unit, motor drive sensor unit, radio modem unit and power supply. 2. The motor drive sensor unit protects the sensor from swift current or freezing and can constantly maintain fixed water level during measurements. 3. This monitoring system can transfer the data by radio modem. Additionally, this system can monitor hydrological conditions in real time. 4. The hardware was made of several modules with an independent CPU. They can be mounted, removed, repaired and added to. Their function can be changed and expanded. 5. These are the result of an accuracy test, the values of temperature, EC and pH measured within an error range of ${\pm}0.2^{\circ}C$, ${\pm}1{\mu}S$ and ${\pm}0.1pH$ respectively. 6. This monitoring system proved to be able to measure various factors for a forest hydrological environment in various experimental stations.

• Korean journal of applied entomology
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• v.47 no.2
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• pp.149-154
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• 2008

Pyrausta panopealis is the major pest in green perilla. The larva weaves a web on the shoot of green perilla and damages. In case of extreme, The larva cuts the main branch of green perilla and the leaf of green perilla isn't harvested anymore. A field study was conducted to estimate economic injury levels (EILs) and control thresholds (CTs) for P. panopealis injuring green perilla in green-houses. Different densities of P. panopealis ranged from 1 to 20 crops (2 units per crop) per 100 crops on 13. June, early inoculation. The number of injured leaf and the rate of injured crop were increased by 23. June, on the other hand were decreased after that day. Also, the amount of yield sow the same result above. The economic loss time calculated by the ratio of cost managing this moth to market price (C/V) (C: cost managing a moth, V: Market price) was 4.0%. The economic injury level was 5.1 larval per 100 crops. The control thresholds calculated by 80% level of economic injury level was 4.1 larval per 100 crops.

• The Korean Journal of Mycology
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• v.44 no.3
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• pp.150-154
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• 2016

To determine a favorable substrate formulation for Grifola frondosa, physicochemical conditions, culture properties, and yields according to various substrate formulations were investigated. Based on these analyses, T4 (80:5:15 ratio of oak sawdust to dried bean-curd refuse to corn husk) resulted in a shorter cultivation period and higher yields (weight of fresh mushrooms harvested at maturity) than those of other treatments. The physicochemical properties of T4 were pH 5.4, 2.4% crude fat contents, 54 C/N ratio, 74.3% porosity, and 0.26 g/cm3 bulk density. These results emphasize the importance of optimal substrate development on the production efficiency of G. frondosa mushrooms and have implications for commercial applications.

• KSBB Journal
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• v.10 no.5
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• pp.510-517
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• 1995

The hydrolysates of three kinds [FSEH(first step enzymatic hydrolysate), SSEH(second step enzymatic hydrolysate), and TSEH(third step enzymatic hydyolysate)] were prepared by continuous hydrolysis of Alaska pollack(Theragra chalcogramma) skin gelatin with three-step membrane enzyme reactor. The molecular weight distributions of FSEH, SSEH, and THSE are 9,500∼4,800Da, 6,600∼3,400Da, and 2,300∼900Da, respectively. The contents of amino acid having sweet taste (glycine, proline, serine, alanine, hydroxyproline, glutamic acid, and aspartic acid) were about 70% of total amino acid being in the three kind hydrolysates. We also tried preparing of natural seasonings (complex seasoning and enzymeatic hydrolysale sauce) using the hydrolysates. From the results of sensory evaluations, complex seasoning containing TSEH was nearly equal to shellfish complex seasoning on the market. The mixture sauce which was made by mixing of 80% enzymatic hydrolysis sauce and 20% fermented soy sauce, was at least similar to the tradition soybean sauce in product quality, too.