• Korean Journal of Ichthyology
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• v.22 no.4
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• pp.256-266
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• 2010

The distribution characteristics of the eggs and larvae of anchovy Engraulis japonica, and environmental factors in the southern coastal waters of Korea were investigated from May to August 2009. Eggs and larvae were mainly distributed in the waters off Naro Island, Namhae Island and Saryang Island. High densities of eggs and larvae in temperatures of $19.0{\sim}24.0^{\circ}C$, salinites of 33.0~34.4 psu, DO of 6.05~8.13 mg/L and chlorophyll-a $1.2{\sim}2.3{\mu}g/L$ were observed. Water temperature in the coastal region was higher than that in the open sea, while salinity was lower. Evidence of sea water intrusion toward Sori Island and Maemul Island, and an inner-water intrusion from Yeoja Bay, Gamak Bay and Gwangyang Bay were observed. High densities of eggs in early developmental stage occurred in waters off Naro Island, Dolsan Island and Namhae Island, but high densities of eggs in a later developmental stage occurred in waters off Yokji Island and Maemul Island. During the survey period, the proportion of later developmental-stage eggs was higher in the eastern part of the study area.

• Korean Journal of Agricultural Science
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• v.5 no.2
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• pp.87-92
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• 1978

Extensive studies on the commercial fermented milks, which had been distributed over four months from July to October in 1978, were carried out for their microbial characterization including an investigation on the variations of bacterial populations under various storage conditions. 1. Total number of viable cells in the products were in between $5{\times}10^7$ cells/ml and $73{\times}10^7$ cells/ml, and $62{\times}10^7$ cells/ml, however no coliform bacteria were detected in the products. 2. Acidities of the products were not very high but fit in the standard as appeared to be in between 0.4869% and 0.6689%. 3. The acidities of the products showed little changes when stored at $5^{\circ}C$, but rises in 22.55% at $20^{\circ}C$ and in 117.66% at $30^{\circ}C$. 4. Total viable counts weren't varied much upto 96 hours when stored at $5^{\circ}C$, but increased during first 24 hours then decreased gradually at the higher temperatures. 5. Viable counts of lactic acid bacteria were decreased markedly with ascending the storage temperature, showing minimal variations when stored at $5^{\circ}C$.

• Journal of Technologic Dentistry
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• v.29 no.1
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• pp.121-131
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• 2007

A preparation process's conditions of aqueous sol which contains anatase-type nano titania particles with photocatalyic properties was established by using Yoldas process, so called, DCS(Destabilization of Colloidal Solution) process in this study. And crystal size change and phase transformation of titania particles in aqueous titania sol depending on reaction conditions was investigated by a light scattering method and XRD analysis of frozen dried powders, respectively. This sol with photo catalytic nano titania particles was used to the following hydrophilic hybrid coating film's fabrication and its properties was evaluated. Subsequently, for coating film using the above mentioned aqueous titania sol, non-aqueous titania sol was prepared without any chemical additives and its time stability according to aging time was investigate. By using the above mentioned aqueous titania sol and non-aqueous sol, a complex oxide coating sol for metal and ceramic substrate and a organic-inorganic hybrid coating sol for polymer substrate was prepared and it's hydrophilicity depending on UV irradiation conditions was evaluated. As a conclusions, the following results were obtained. (1)Aqueous titania sol The average particle size of titania in formed aqueous titania sol was distributed between 20$\sim$90nm range depending on reaction conditions. And the crystal phase of titania powders obtained by frozen drying method was changed from amorphous state to anatase and subsequently transformed to rutile crystal phase and it is attributed to concentration gradient in aqueous sol. (2)Non-aqueous titania sol Non-aqueous titania sol was prepared using methanol as a solvent and a little distilled water for hydrolysis and nitric acid as a catalyst were used. The obtained non-aqueous titania sol was stable at room temperature for 20 days. Additionally, non-aqueous titania sol with addition of chealating reagent such as acethylaceton and ethylene glycol prolonged the stability of sol by six months. (3)Complex sol and hybrid sol with super hydrophilicity The above mentioned aqueous titania sol as a main photocataylic component and non-aqueous titania sol as a binder for coating process was used to prepare a complex sol used for metal, ceramic and wood material substrate and also to prepare the organic-inorganic hybrid sol for polymer substrate such as polycarbonate and polyethylene, in which process APMS(3-Aminopropyltrimethoxysilane), GPTS(3-Glycidoxypropyl-trimethoxysilane) as a hydrophilic silane compound and HEMA(2-Hydroxyethyl methacrylate) as a forming network in hybrid coating film were used. The hybrid coating film such as prepared through this process showed a superhydrophilicity below 1$10^{\circ}$ depending on processing conditions and a pencil's hardness over 6 H.

• Journal of Aquaculture
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• v.9 no.4
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• pp.409-417
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• 1996

Age, annual growth pattern, and other ecologically important observations are reporting from the analysis of annual growth annuli of the sun and moon scallop, Amusium japonicum. Field survey made from 1993 to 1994 indicated that the sun and moon scallops are mostly distributed along the southern coast of Cheju-do, especially around the Sogwipo area. They inhabit on muddy sand bottom, at depth between 30 and 40 m where water temperature varies from 14 to $23^{\circ}C$ annually. The gonadal analysis indicated that the spawning mostly occurs during October and December and they exhibit multiple spawning peaks. The formation of annual growth annuli was found to be related with their spawning period. The shell growth on A. japonium japonicum appeared that their shell growth rate is comparatively faster than that of other scallops : 1. japonium japonicum reaches 6.28 cm in shell hight at the first year and 9.07 cm at the second year. The growth rate of gonadal somatic tissue was also found to be faster than growth rates of other scallops. One year old scallops weigh about 18.8 g, two and three year old scallops weigh 60 and 102.4 g. Based upon these observations, it is concluded that A. japonium japonicum can be a valuable species for aquaculture development due to their rapid growth.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.4
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• pp.323-328
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• 1982

Kareius bicoloratus (Basilewsky) is one of the commonly found right-eye flounders and widely distributed in the coastal waters of Korea and Japan. On December 11,1980, the ailthors carried out an experiment to obtain a large number of fertilized eggs from wild adult fish caught by a trawler. The fish were obtained from Maisaka fish market, Shizuoka Prefecture, Japan. The egg is pelagic, spherical in shape and measuring 1.014-1.04 mm in diameter. The yolk as well as the egg capsule is colorless and transparent, and contain no oil globules. The hatching took place in 73 hr 45 min after fertilization at the water temperature $8.0-9.5^{\circ}C$. Newly hatched larvae are 3.09-3.146 mm in total length, with the anus situated in the middle of the body. The marginal fin does not have Pigment cells and myotome number is 17+20=37. Within one day after hatching, the larvae attained 3.77 mm in total length, and there appeared three or four melanophore on yolk sac. When the larvae attained 3.96 mm in total length, melanophores began to appear on the eye ball. Two days after hatching, the larvae attained 4.05 mm in total length, most of yolk material was absorbed, and the caudal fin began to grow at the terminal part of the notochord. When the larvae attained 4.21 mm in total length, mouth and eyes began to move. After 3 days, the larvae attained 4.342-4.394 mm in total length, alimentary canal differentiated, melanophores appeared on the lower jaw and posterior part of the fin membrane. When the larvae attaind 4.576 mm in total length, marginal line of dorsal fin membrane became concave.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.415-419
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• 2007

This study was conducted to compare the storability of some sprout vegetables; alfalfa, broccoli, radish, red-cabbage, and red-radish, packed with 50 low density polyethylene (LDPE) film in MA storage. Most of all 5 different sprout vegetable crops maintained the fresh weight higher than 99% until 10 days storage at 2 and $8^{\circ}C$. The carbon dioxide concentration in packages was higher at 8 than at $2^{\circ}C$. It was higher in radish and red-radish sprouts than other crops. As the oxygen concentration showed opposite trends to carbon dioxide, that of radish and red-radish sprouts decreased more than 3% after 3 days in 8 storage. Ethylene concentration in the packages of alfalfa was 0.1 ppm, significantly higher than other four crops with less than 1.0 ppm. Temperature treatment, however, did not influence the ethylene concentration in packages. The radish and red-radish sprouts, with lowest oxygen concentration in package, showed lowest off-flavor compared to the others. The visual quality of these sprouts in packages showed higher at $2^{\circ}C\;than\;at\;8^{\circ}C$ and was maintained the highest in radish sprouts, followed by red-radish, broccoli, red-cabbage, and alfalfa sprouts in that order. In conclusion, as the sprout vegetables have different shelf-life, of which radish was $4{\sim}5$ days longer than that of alfalfa the distributed condition of sprout vegetables should be differently controlled according to kinds of crops.

• Korean Journal of Ichthyology
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• v.10 no.1
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• pp.1-10
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• 1998

The early history of Korean mandarin fish, Siniperca scherzeri was studied to obtain some information required in aquaculture and reinforcement of natural population. During the period from June 1996 to July 1997, the mature adults of Siniperca scherzeri were collected from the middle Soyang Lake at Puksan - myon, Chunchon - shi, Kangwon - do, Korea. The eggs from females were obtained by injecting HCG or/and GnRH - a and fertilized by dry method in the laboratory. The fertilized eggs, measuring 1.70~2.10 mm in diameter and expanded to 2.20~2.66mm after absorption of water, were globosity, light orange yellow, separative, submergence and had one large oil globules of 0.5~0.7 mm. The blastodisc was formed in 1 hour and cleavage started in 1 hour 30 min. after fertilization, and the intervals of each stage of cleavage was about 50 min. at the water temperature of $21{\sim}24^{\circ}C$. Hatching occurred 131 hours 30 min. after fertilization and newly hatched larvae were 5.86~6.85 mm in total length(TL) and numerous stellate melanophores were distributed on the yolk and abdomen of caudal peduncle. The yolk was almost absorbed and the teeth development. 3 days after hatching, at 6.98~7.60 mm TL. The head spines and the teeth were largely developed and all fins were completely formed and became postlarva stage 15 days after hatching, at 10.10~12.90 mm TL. The body shape and the color pattern were similar to adult, 25 days after hatching, at 15.3~23.8 mm TL. In 5 months after hatching were reached at 154.10~175.02 mm TL and 49.32~82.67 g in body weight.

• Korean Journal of Optics and Photonics
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• v.5 no.3
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• pp.423-430
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• 1994

We designed and fabricated the single mode fiber pigtailed DFB-LD module for 2.5 Gbps optical communication system. In the design of the DFB-LD module, we made the module divided into two parts of inner sub-module and outer 14-pin butterfly package and cylindrical shaped sub-module contain quasi confocal 2 lens system including optical isolator and electrical connection between these parts via hybrid substrate of bias T circuit. Laser welding was used to assemble the sub-module which requires accurate fixing between optical elements. The fabricated DFB-LD module showed optical coupling efficiency of 20% and - 3 dB small signal response of more than 2.6 GHz. We confirmed mechanical reliability of the module by temperature cycle test where the tested module exhibit optical power fluctuation of less than 10%. Finally we evaluated the performance of the fabricated DFB-LD module as light source of 2.5 Gbps optical communication system, sensitivity of - 30.2 dBm was obtained through 47 km optical fiber transmission under the criterion of $1\times10^{-10}$ BER and transmission penalties were 1.5 dB caused by extinction ratio and 1.0 dB caused by chromatic dispersion of normal single mode fiber. fiber.

• Economic and Environmental Geology
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• v.29 no.5
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• pp.545-559
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• 1996

Rare metal (Nb-Zr-REE) ore deposits are located in the Chungju area. Geotectonically, the rare metal ore deposits are situated in the transitional zone between Kyeonggi massif and Okcheon belt. The rare metal deposits are distributed in Kyemyeongsan Formation which consist of schist and alkaline igneous rocks. Alkali granite has suffered extensive post-magmatic metasomatism and hydrothermal processes. The ore contains mainly Ce-La, Ta-Nb, Y, Y-Nd, Nd-Th group minerals. More than 15 RE and REE minerals are found in the ore deposits. Allanite, one of the Ce-La rich REE minerals belonging to the epidote group, is the most common mineral in the studied area. The allanite- bearing rocks may be devided into seven types by features of occurrence and mineral associations; zircon type (ZT), allanite-vein type (AT), feldspar type (KT), fluorite type (FT), quartz-mica type (QT), iron-oxide type (MT), and amphibole type (HT). The allanite veins (AT) and zircon rich rocks (ZT) contain the highest total REE contents. Differences in REE abundance can be interpreted in terms of varying portions of magmatic hydrothermal fluid. Petrographical and chemical data are presented for allanites which were collected from different types. The allanites show wide variations in optical properties, due in part to differences in their chemical composition (depending on the types) and to the degree of crystallinity of the individual specimens. Allanite metamicts in biotite are generally surrounded by well developed pleochroic haloes. Usually, allanite is accompanied by zircon and other REE-bearing minerals. CaO and total REE contents $({\sum}RE_2O_3)$ range from 9.29 to 18.79% and 11.66 to 26.31%, respectively. Also, SiO, (28.87~32.61%), $Al_2O_3$ (8.30~16.88%), and $Fc_2O_3$ (16.74~24.38%) contents show varying contents from type to type. The ${\sum}RE_2O_3$ of allanite has positive relationships with $Fe_2O_3$ and negative relaton with CaO, $SiO_2$, and $Al_2O_3$ Backscattered electron microscope images (BEl) of allanite shows that the its mineral composition and texture is very complex. The allanite-bearing hosts show distinct light REE enrichment with strong negative Eu anomaly except for HI. The HT has an almost flat REE distribution pattern with a small negative Eu anomaly. The chemical variation of the allanites with occurrences and mineral association can be related to condition of temperature and oxidation states in precipitation environment.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.1
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• pp.1-10
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• 2006

Concentration and identification of airborne bacteria in the regulated public facilities were examined with the six-stage cascade impactor. Geometric mean total and respirable concentrations of airborne bacteria were $404cfu/m^3$ and $194cfu/m^3$ in hospital, $931cfu/m^3$ and $358cfu/m^3$ in kindergarten, $294cfu/m^3$ and $134cfu/m^3$ in day-care center, and $586cfu/m^3$ and $254cfu/m^3$ in postpartum nurse center, respectively. As a result, culturable total and respirable concentrations of airborne bacteria were significantly highest in kindergarten and lowest in day-care center (p<0.05). The ratio of respirable to total concentration of airborne bacteria in the investigated public facilities was ranged from 30% to 40% but there was no significant difference among them (p>0.05). The mean I/O ratio of culturable total and respirable concentrations were 0.58 and 0.66 in hospital, 0.71 and 0.83 in kindergarten, 0.28 and 0.41 in day-care center, and 0.63 and 0.78 in postpartum nurse center, respectively. Day-care center showed the lowest I/O ratio of culturable total and respirable concentration of airborne bacteria (p<0.05) but a significant difference was not found among other facilities. Indoor concentration of airborne bacteria did not correlated significantly with indoor temperature and relative humidity (p>0.05) but had a significant positive correlation with $CO_2$ and surrounding condition (p<0.05). Staphylococcus spp., Micrococcus spp., Corynebacterium spp., and Bacillus spp. were dominant genera and amounted to over 95% of total airborne bacteria identified in the investigated public facilities. Size distributions of four dominant genera did not observed inconsistently regardless of type of public facility.