• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.1026-1031
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• 2003

The two-level full factorial and mixture design were used to screen ingredient type and to investigate effects of ingredients on properties of alkali surimi gel from frozen white croakers using measurements of a breaking force, deformation and color. The addition of starch decreased a breaking force and deformation of gel regardless of starch type. The breaking force was decreased, but a deformation was not significantly changed (p<0.05) with increasing starch level. The potato starch was more resonable than com and wheat starch for a breaking force and deformation. The bovine plasma protein (BPP) greatly improved a breaking force and deformation. The breaking force and deformation of gel were increased with concentration of BPP. The whiteness of gel was slightly improved with adding starch and non-muscle for all treatments. At 78% moisture, the optimum ratios of ingredients were 89.4∼90.0% for surimi, 5.9∼6.3% for potato starch and 5.0∼5.4% for BPP to obtain above 100g for a breaking force, 4.6 mm for a deformation, and 25.5 for a whiteness.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.3
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• pp.149-158
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• 2012

This study analyzed cross-sectional variations in residual current and strengths of stratification by observing cross-sectional velocity and salinity during spring tide and neap tide, respectively, for continuous 13-hour periods at 2 observation lines at northern and southern end of Seokmo Channel, which is located west of Ganghwado. Salinity distribution of channel depends on not only neap and spring tide but also impact of salinity. The residual current component was obtained by removing $M_2$ and $M_4$ tidal components that were extracted using the least squares method on 13-hour velocity component. Cross-section of residual velocity at northern and southern end of Seokmo Channel exhibited southward residual components at channel's surface layer, but northward residual current was observed at channel's bottom layer, clearly showing a 2-layer tidal circulation between surface and bottom layers. The variation in location of appearing northward residual current according to changes in spring and neap tidal cycle and its correlation with stratification were analyzed using the Richardson number and Simpsonhunter index. At northern and southern end of Seokmo Channel, northward residual current appears in the location where Richardson number is large, Simpson-hunter index appears as a value greater than 4.

• Analytical Science and Technology
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• v.17 no.3
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• pp.240-250
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• 2004

A gas chromatography-mass spectrometric (GC-MS) assay method was developed for the rapid and sensitive determination of volatile- and semivolatile organic compounds in water. Two hundreds mL of water sample was extracted in a 250 mL separatory funnel with 1 ml of pentane at pH 6.5. Fluorobenzene and 1,2-dichlorobenzene-d4 as internal standards were added to water sample and the solution was mechanically shaken for 5 min and analyzed by GC-MS (selected ion monitoring) without more any concentration or purification steps. The peaks had good chromatographic properties and the extraction of these compounds from water also gave relatively high recoveries with small variations. The range of detection limits of the assay was 0.5-10 ng/L. Turnaround time for up to about 40 samples was one day. This method is simple, convenient, and can be learned easily by relatively inexperienced personnel. This method was used to analyze 15 volatile- and semivolatile organic compounds in water of a Lake, and raw and treated water from three Water Treatment Plants in Korea. As the analytical results, benzene, toluene, xylene, isopropylbenzene, 1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, naphthalene and 2,4,6-trichlorophenol were detected at concentrations of up to 0.4, 1.9, 1.3, 0.2, 1.8, 13.0, 1.7 and $1.1{\mu}g/L$, respectively. But chlorobenzene, trichloroethylene, tetrachloroethylene, ethylbenzene, n-butylbenzene and dibromochloropropane levels during that period were not significant. The removal effect of the compounds in three Water Treatment Plants was calculated. The compounds studied were generally removed during conventional water treatment, especially during the active carbon filtration.

• Journal of the Korean Electrochemical Society
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• v.14 no.1
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• pp.16-21
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• 2011

$Li_4Sn_xTi_{5-x}O_{12}$ was manufactured by high energy ball milling (HEBM) and used as an anode material for lithium ion battery. Various amount of $SnO_2$was added to $Li_4Ti_5O_{12}$ and heated at different temperatures. The purpose of this research was to see the effect of $SnO_2$ addition into $Li_4Ti_5O_{12}$. Manufactured samples were analyzed by TGA, XRD, SEM, PSA. Battery cycler was used to test the charge/discharge properties of active materials. Heat treatment temperature of $800^{\circ}C$ was needed to make a stable structure of $Li_4Sn_xTi_{5-x}O_{12}$ and the particle size distribution was $0.2{\sim}0.6\;{\mu}m$. Charge/discharge process was repeated for 50 cycles at room temperature. The initial capacity was 168mAh/g and the voltage plateau was observed at 1.55V(Li/$Li^+$).

• Korean Journal of Ecology and Environment
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• v.47 no.spc
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• pp.57-65
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• 2014

Spatial and temporal distributions of zooplankton were measured in an oligotrophic pumped storage-type hydroelectric reservoir which was composed of two reservoirs exchanging water daily, with water going up at night and going down during the day. Repetitive diel disturbance of the water column can be a unique feature of this reservoir system. Chl-${\alpha}$ concentration was highest in the early winter season. Phytoplankton density was lower in summer monsoon due to high flushing rate on rainy days. The zooplankton density was higher in the smaller upper reservoir possibly due to lower fish density in the upper reservoir. In the seasonal variation a time gap was observed between the phytoplankton bloom and the zooplankton bloom (particularly a rotifer, Keratella cochlearis). It is likely to that Keratella production is partially supported by heterotrophic food sources than phytoplankton. The dominance of a mixotrophic dinoflagellate (Peridinium bipes f. ocultatum) might have complicated the trophic relationship between phytoplankton and zooplankton. Our results provide some ecological information of zooplankton community in a highly disturbed alpine reservoir ecosystem relying on mostly allochthonous organic matter.

• Clean Technology
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• v.27 no.3
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• pp.223-231
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• 2021

In order to address many issues associated with large volume changes of silicon, which has very low electrical conductivity but offers about 10 times higher theoretical capacity than graphite (Gr), a silicon nanoparticles/hollow carbon (SiNP/HC) composite having bimodal-mesopores was prepared using silica nanoparticles as a template. A control SiNP/C composite without a hollow structure was also prepared for comparison. The physico-chemical and electrochemical properties of SiNP/HC were analyzed by X-ray diffractometry, X-ray photoelectron spectroscopy, nitrogen adsorption/desorption measurements for surface area and pore size distribution, scanning electron microscopy, transmission electron microscopy, galvanostatic cycling, and cyclic voltammetry tests to compare them with those of the SiNP/C composite. The SiNP/HC composite showed significantly better cycle life and efficiency than the SiNP/C, with minimal increase in electrode thickness after long cycles. A hybrid composite, SiNP/HC@Gr, prepared by physical mixing of the SiNP/HC and Gr at a 50:50 weight ratio, exhibited even better cycle life and efficiency than the SiNP/HC at low capacity. Thus, silicon/carbon composites designed to have hollow spaces capable of accommodating volume expansion were found to be highly effective for long cycle life of silicon-based composites. However, further study is required to improve the low initial coulombic efficiency of SiNP/HC and SiNP/HC@Gr, which is possibly because of their high surface area causing excessive electrolyte decomposition for the formation of solid-electrolyte-interface layers.

• Economic and Environmental Geology
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• v.38 no.6 s.175
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• pp.633-642
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• 2005

We present the sedimentary sequence and distribution pattern of the late Holocene muddy deposits in the northern East China Sea shelf using the high-resolution 'Chirp' profiles. The seismic sedimentary sequence overlying acoustic basement (basal reflector-B) can be divided into two depositional units (Unit 1 and 2) bounded by erosional bounding surface (mid reflector-M). The lower Unit 1 above basal reflector-H is characterized by the acoustically parallel to subparallel reflections and channel-fill facies. The upper Unit 2, up to 7 m in thickness, shows seismically semi-transparent seismic facies and lenticular body form. On the base of sequence stratigraphic concept, these two sediment units have developed during transgression and highstand period, respectively, since the last sea-level lowstand. The transgressive systems tract (Unit 1) lie directly on the sequence boundary (reflector B) that have farmed during the last glacial maximum. The transgressive systems tract in this study consists mostly of complex of delta, fluvial, and tidal deposits within the incised valley estuary system. The maximum flooding surface (reflector M) corresponding to the top surface of transgressive systems tract is obviously characterized by erosional depression. The highstand systems tract (Unit 2) above maximum flooding surface is made up of the mud patch filled with the erosional depression. The high-stand mud deposits showing a circle shape just like a typhoon symbol locates about 140 km off the south of Cheju Island with water depth of $60\~90m$. Coverage area and total sediment volume of the mud deposits are about $3,200km^2$ and $10.7\times10^9\;m^3$, respectively. The origin of the mud patch is interpreted as a result of accumulating suspended sediments derived from the paleo-Yellow and/or Yangtze Rivers. The circular distribution pattern of the mud patch appears to be largely controlled by the presence of cyclonic eddy in the northern East China Sea.

• Economic and Environmental Geology
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• v.19 no.4
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• pp.243-264
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• 1986

This work is a metallogeny on gold-silver deposits in South Korea based on the close examination of the author's own data and a broad review of existing literature available. The metallogenic epochs in Korea are temporarily connected with the history of tectonism and igneous activities, and are identified as the Precambrian, Paleozoic, Jurassic to early Cretaceous, late Cretaceous to early Tertiary, and Quaternary epochs, whereas the metallogenic provinces are spatially associated with some of the felsic to intermediate igneous rocks, lacking mineralization related to basic and ultrabasic rocks. The metallogeny on the gold-silver deposits is mostly related to the granitic rocks intrusives. Epigenetic gold-silver mineralization in South Korea ranges in metallogenic epochs from Precambrian through Triassic, Jurassic and Cretaceous to Eocene (?), in genetic types from hypothermal through mesothermal and epithermal quartz-sulfide veins to volcanogenic stockworks, with some disseminated types. Reporting on metallic association from gold without silver, gold-silver, silver-gold, silver without gold, and gold or silver as a by-product from other metallic ores. The most representative genetic types and metal associations of gold-silver deposits are hydrothermal quartz veins associated with the Daebo and Bulgugsa granitic magmatism. The most closely associated paragenetic metallic minerals in gold-silver hydrothermal quartz-sulfide vein type deposits are: copper, lead, zinc, pyrite and arsenopyrite. More than 560 gold-silver mines are plotted in the distribution map grouped within the 10 different metallogenic provinces of South Korea. Specific mineralizations with related mineral association in both sulfides and gangues observed selected from 18 Korean and 8 Japanese Au-Ag deposits. The 7 selected individual gold-silver mines representing specific mineralization types are described in this report.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.2
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• pp.69-79
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• 2009

Major and trace elements were analyzed in three core sediments to investigate geochemical characteristics of East Sea sediments and provenance changes during late Quaternary in Ulleung Basin. Comparing with Yellow and South Sea sediments, contents of major elements were generally similar while contents of trace elements were significantly different. Furthermore, within this basin, there were some variabilities in trace element compositions. In the western slope sediments (WS), Mo was enriched over 6 times as much as other sites. On the other hand, Zr, Nb, Hf and Ta were enriched in basin sediments (Basin), and Ca and Cs were enriched in southern slope sediments (SS). After excluding elements derived from biogenic, authigenic and diagenetic origins, the lithogenic elements (K, Ti, Cs, Zr, Nb, Hf and Ta) could be classified into three groups from the comparison of element/Al ratios among cores. The first group consisted of elements (K and Ti) that showed the nearly similar element/Al ratios among three cores. The second group contained Cs which showed significant difference between two slope sediments. The third group elements (Zr, Nb, Hf and Ta) showed highly enriched in basin relative to both slope areas. The depth profiles of metal/Al ratios in basin sediments provided the following interpretation for the compositions of sediment and their variation. From 10,000 yr B.P. to 7,000 yr B.P. two lithogenic components (volcanic ashes and western slope sediments) were mixed and deposited in the basin. After 7,000 yr B.P., however, southern slope sediments were mixed with volcanic ashes and deposited in basin area. This event of source change is nearly close to inflow period of the Tsushima Warm Current to Ulleung Basin. Thus, it might be suggested that element geochemistry in Ulleung basin sediment indicate the change of current system in the study area.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.59-73
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• 1982

Differences of lipids, especially total lipid composition, fatty acid and sterol composition of the flesh lipids between three species of cephalopods were investigated, since available researches concerning lipids in flesh tissues of the cephalopod are very limited. Extracted total lipid from the flesh tissues were fractionated by silicic acid column chromatography into three lipid classes of neutral lipids, glycolipids and phospholipids. The lipid compositions of total lipid and neutral lipids were estimated by the method of thin layer chromatography and TLC-scanner. The sterol compositions of unsaponifiable matters from total lipid were determined by using thin layer chromatography and gas-liquid chromatography. The fatty acid composition of each lipid class was also determined by gas-liquid chromatography. Total lipid contents of flesh tissues from three species of the cephalopods were 0.5 in Octopus vulgare, 0.8 in Octopus variabilis and $0.6\%$ in Loligo beka based on wet weight, the contents of total fatty acid in total lipid were 19.3, 47.8 and $38.4\%$, and the contents of unsaponifiable matters were 10.9, 18.8 and $41.1\%$, respectively. Total lipid was mainly composed of sterols and polar lipid-pigments as major components in each sample and the proportion of sterols and polar lipid-pigments to total lipid ranged from 27.0 to $35.5\%$ and 38.3 to $63.4\%$, respectively. The other lipid components of total lipid, e.g. triglycerides, free fatty acids, and carbohydrate-esterified sterols were determined as a minor components. The major component fatty acid in total lipid was palmitic acid and additionaly it chiefly consisted of the other unsaturated acids such as oleic, linoleic, octadecatetraenoic and eicosapentaenoic acid as major components of the acid. The compositions of sterol in three species of cephalopod were found to contain mainly cholesterol for its proportion to total sterols was 82.4 to $89.1\%$. However the other sterols such as 22-dehydrocholesterol and 24-methylenecholesterol were determined in addition to cholesterol as a minor components. The result of fractional composition of lipid class in total lipid was that total lipid had large .amount of polar lipid and small amount of nonpolar lipid i, e, neutral lipid in each sample, and the contents of phospholipid were higher than that of glycolipid in polar lipid. Neutral lipid was mainly composed of free sterol as major components in each sample and its proportion of free sterols to total neutral lipid was 50.0 to $70.5\%$. The other lipid components of neutral lipid showing similar in quantity, esterified sterols, free fatty acids and triglycerides were determined as a minor components. The major components fatty acid in neutral lipid were palmitic, oleic and hexadecadienoic acid. Palmitic acid was the most abundant and additionaly oleic, linoleic, octadecatetraenoic and myristic acid were the major component fatty acid in glycolipid. But, especially, glycolipid of Loligo beka contained a higher amount of arachidonic acid which also consists of major component in addition to those of acids. Palmitic acid was the most abundant and additionaly, oleic, linoleic and octadecatetraenoic acid were the major component fatty acids in phospholipid.