• Journal of the Korean Society for Marine Environment & Energy
• /
• v.8 no.2
• /
• pp.83-99
• /
• 2005

To evaluate environmental charateristics of the South Sea and East China Sea on summer, water and sediment quality were measured in June 2001-2003. Surface layer was affceted by Warm water originated from the high temperature and salinity-Tsushima Warm Current, on the other hand, Yellow Sea Cold Water was spread to the bottom layer in the south-western part of the Jeju island, and salinity at stations near the Yangtze River was decreased below 29psu because of a enormous freshwater discharges. Thermocline-depth was formed at about 10m, and chlorophyll maximum layer was existed in and below the thermocline. COD(Chemical Oxygen Demand), TN(Total Nitrogen), and TP(Total Phosphorus) concentrations showed seawater quality grade II in surface layer of the most area, but concentrations of such as COD, Chl. a, TSS(Total Suspended Solid), and nutrients were greatly increased in the effect area of Yangtze River discharges. Correlations between dissolved inorganic nitrogen, Chl. a and salinity were negative patterns strongly, in contrast, those of inorganic phosphorus, COD and Chl. a were positive, which indicates that phytoplankton biomass and phosphorus are considered as important factors of organic matter distribution and algal growth, respectively. in the study area. The distribution of ignition loss, COD, and $H_2S$ of surface sediment were in the ranges of 2.61-8.81%, $0.64-11.86mgO_2/g-dry$, and ND-0.25 mgS/g-dry, respectively, with relatively high concentration in the eastern part of the study area. Therefore, to effective and sustainable use and management of this area, continuous monitoring and countermeasures about major input sources to the water and sediment, and prediction according to the environmental variation, are necessary.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.30 no.3
• /
• pp.393-407
• /
• 1997

A survey of biological and chemical characteristics in the middle-northern East Sea of Korea was carried out at 28 stations in October, 1995 on board R/V Tam-Yang. On the basis of the vertical profiles of temperature, salinity and dissolved oxygen, water masses in the study area were divided into 5 major groups; (1) Low Saline Surface Water (LSSW), (2) Tsushima Surface Water (TSW), (3) Tsushima Middle Water (TMW), (4) North Korean Cold Water (NKCW), (5) last Sea Porper Water (ESPW). Other 4 mixed water masses were also observed. It is highly possible that the LSSW which occured at depths of $0\~30m$ in the most southern part of the study area is originated from the Yangtze River (Kiang) of China due to very low salinity $(<32.0\%_{\circ})$ relatively high concentration of dissolved silicate and no sources of freshwater input into that area. Oxygen maximum layer in the vertical profile was located near surface at northern cold waters and became deeper at the warm southern area. Oxygen minimum layer af depths $50\~100m$, which is TMW, were found in only southern area. In the vortical profiles of nutrients, the concentrations were very low in the surface layer and increased drammatically near the thermocline. The highest concentration occurred in the ESPW. The relatively low value of Si/P ratio in the ESPW (13.63) compared to other reports in the East Sea was due to continuous increase of P with depth as well as Si. The N : P ratio was about 6.92, showing that nitrogenous nutrient is the limiting factor for phytoplankton growth. The exponential relationship between Si and P, compared to the linear relationship between N and P, indicates that nitrate and phosphate have approximately the same regenerative pattern, but silicate has delayed regenerative pattern.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.14 no.2
• /
• pp.182-187
• /
• 1985

This study was attempted to evaluate the chemical components of Aldaegu, Gadus macrocephalus, which consumed as a salted and dried product popularly in Korea. The contents of such compounds as amino acids, nucleotides and their related compounds, fatty acids and minerals were analysed. The content of total free amino acids was 814.9 mg% on dry basis and the major amino acids were tyrosine, alanine, histidine, leucine, phenylalanine, lysine and valine in a decreasing order. These amino acids were resulted as 45% of total free amino acids in Aldaegu. In the nucleotides and their related compounds, inosine and hypoxanthine were the only compounds detected. The overall content of nucleotide and their related nitrogenous compounds, free amino acid-N., ammonia-N., creatine and creatinine-N., and betaine-N., was 78.6% of extractable nitrogen. Ammonia-N was the most abundant of other nitrogenous compounds, resulting 36.6% of extractable nitrogen from the sample. In the fatty acid composition of total lipid and phospholipid, polyenoic fatty acid was abundant holding about 48% respectively. However, higher amounts of saturated fatty acids(39.8%) were found in glycolipid, and the predominant fatty acids in quantity were palmitic $acid(C_{16:0})$, stearic acid $(C_{18:0})$, oleic $acid(C_{18:1})$, docosahexaenoic $acid(C_{22:6})$, eicosapentaenoic $acid(C_{20:5})$ and eicosatetraenoic $acid(C_{20:4})$. Aldaegu contained 27,430 ppm of sodium and the trace amount of lead and cadmium was detected, which gave a good safety in the food sanitation aspects. It was presumed that free amino acids, ammonia, hypoxanthine, betaine, creatine and creatinine, and minerals play an important role for the characteristics of taste and flavor of Aldaegu.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.10
• /
• pp.1307-1313
• /
• 2007

In order to evaluate the utilization of immature green wheat kernels as food processing material, these experiments were carried out to analyze general composition, free sugars, free amino acids, mineral content and color of 3 wheat varieties according to their heading dates. Contents such as moisture, crude protein, crude lipid and ash were gradually decreased according to the days after heading of 3 wheat varieties, while crude fiber and starch were gradually increased. Maltose and maltotriose contents in immature green wheat kernels were high but its rapidity decreased by closing to ripeness. Contents of free amino acids showed a tendency to decrease, among which alanine content was the highest around 25 days after heading, and then glutamic acid, GABA, glycine in order. Contents of total free amino acid were decreased by closing to ripeness. Among 3 wheat varieties, its contents of Guru wheat was the highest. As wheat matured, ${\beta}-glucan$ contents were decreased from 1.5% to 0.28% on 43 days after heading. Mineral contents of 3 wheat varieties were generally increased by closing to ripeness after coming into ears, and K, Mg were especially prominent. As wheat matured, lightness was decreased, while redness and yellowness were increased. Considering chemical composition and color, the immature green wheat were produced through blanching the spikes harvested before the yellow ripe stage. The harvested green wheat cereals is able to eat raw wheat or cook it as food processing material.

• Journal of Korean Society of Forest Science
• /
• v.90 no.5
• /
• pp.608-618
• /
• 2001

To understand the weathering processes of the soil by submicroscopic method is very important to realize the properties of the soils. In this study soil formation processes show every steps to the changes in chemical and mechanical properties and the submicroscopic characteristics of soil weathering on the profiles of forest soils derived from granite in southern part of Korea. Fecal pellets(SEM) are given a full detail of the positive activities of the forest soil animals; mainly invertebrates in the O horizon and the E horizon. External shapes of fecal pellets have been divided into five groups : spherical, ellipsoidal, cylindrical, platy and threadlike. But doughnutlike form of fecal pellets is observed in this study. The soluble and suspended materials in the soils move downwards by percolation from the A horizon to the B or the BC horizons, and result in the illuviation cutans(SEM) on the ped surface of the lower horizon and deposited stack of kaolinite. Illuviated cutans are deposited on the ped surface even in the depth of 312cm in the BC horizon as well as the Bt horizon and comprise of fine silt, coarse clay and fine clay. A lot of halloysites are observed on the cutan surface. Halloysite formation from feldspars has been well known but a lot of hallyosite formation are observed in this study. The formation were predicted by Jackson(1962), inferred by Wada and Kakuto(1983a, b) and proved evidently by Cho and Mermut(1992a, b). This also suggests that halloysites in the soils derived from granite are formed a lot from ferruginous chlorites. The release of Fe from the chlorite structure are significant pedogenic processes and newly formed Fe oxides imparted a red color to the soils. The iron oxides particles, which are ejected and recrystalized, aggregate thickly on the edge of the ferruginous chlorites, and this indicates the release of structural Fe from weathered chlorites. Hematites and goethites are frequent in the fine clay in this soils.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2003.05a
• /
• pp.91-93
• /
• 2003

A comprehensive numerical study is carried out to investigate for the understanding of the flow evolution and flame development in a supersonic combustor with normal injection of ncumally injecting hydrogen in airsupersonic flows. The formulation treats the complete conservation equations of mass, momentum, energy, and species concentration for a multi-component chemically reacting system. For the numerical simulation of supersonic combustion, multi-species Navier-Stokes equations and detailed chemistry of H2-Air is considered. It also accommodates a finite-rate chemical kinetics mechanism of hydrogen-air combustion GRI-Mech. 2.11[1], which consists of nine species and twenty-five reaction steps. Turbulence closure is achieved by means of a k-two-equation model (2). The governing equations are spatially discretized using a finite-volume approach, and temporally integrated by means of a second-order accurate implicit scheme (3-5).The supersonic combustor consists of a flat channel of 10 cm height and a fuel-injection slit of 0.1 cm width located at 10 cm downstream of the inlet. A cavity of 5 cm height and 20 cm width is installed at 15 cm downstream of the injection slit. A total of 936160 grids are used for the main-combustor flow passage, and 159161 grids for the cavity. The grids are clustered in the flow direction near the fuel injector and cavity, as well as in the vertical direction near the bottom wall. The no-slip and adiabatic conditions are assumed throughout the entire wall boundary. As a specific example, the inflow Mach number is assumed to be 3, and the temperature and pressure are 600 K and 0.1 MPa, respectively. Gaseous hydrogen at a temperature of 151.5 K is injected normal to the wall from a choked injector.A series of calculations were carried out by varying the fuel injection pressure from 0.5 to 1.5MPa. This amounts to changing the fuel mass flow rate or the overall equivalence ratio for different operating regimes. Figure 1 shows the instantaneous temperature fields in the supersonic combustor at four different conditions. The dark blue region represents the hot burned gases. At the fuel injection pressure of 0.5 MPa, the flame is stably anchored, but the flow field exhibits a high-amplitude oscillation. At the fuel injection pressure of 1.0 MPa, the Mach reflection occurs ahead of the injector. The interaction between the incoming air and the injection flow becomes much more complex, and the fuel/air mixing is strongly enhanced. The Mach reflection oscillates and results in a strong fluctuation in the combustor wall pressure. At the fuel injection pressure of 1.5MPa, the flow inside the combustor becomes nearly choked and the Mach reflection is displaced forward. The leading shock wave moves slowly toward the inlet, and eventually causes the combustor-upstart due to the thermal choking. The cavity appears to play a secondary role in driving the flow unsteadiness, in spite of its influence on the fuel/air mixing and flame evolution. Further investigation is necessary on this issue. The present study features detailed resolution of the flow and flame dynamics in the combustor, which was not typically available in most of the previous works. In particular, the oscillatory flow characteristics are captured at a scale sufficient to identify the underlying physical mechanisms. Much of the flow unsteadiness is not related to the cavity, but rather to the intrinsic unsteadiness in the flowfield, as also shown experimentally by Ben-Yakar et al. [6], The interactions between the unsteady flow and flame evolution may cause a large excursion of flow oscillation. The work appears to be the first of its kind in the numerical study of combustion oscillations in a supersonic combustor, although a similar phenomenon was previously reported experimentally. A more comprehensive discussion will be given in the final paper presented at the colloquium.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.4 no.4
• /
• pp.388-395
• /
• 2016

This paper explores the photocatalytic sensitivity of cement mortar incorporated with recycled $TiO_2$ from waste water sludge. Basically, $TiO_2$ cluster sank down slowly to the bottom of cement mortar specimen before setting and hardening process. This leads the mismatch of $TiO_2$ concentration on the top and the bottom faces of a specimen. This poorly dispersed $TiO_2$-cement mortar naturally exhibits poor NOx removal efficiency especially on the top of cementitious structure. In architectural engineering application such as building or housing structures, one can simply filp over from the bottom so that more $TiO_2$ concentrated surface can be placed outward into the air. However, in highway pavement case, this could not be applicable due to in-situ installation of concrete pavement. Hence, the dispersion of $TiO_2$ cluster inside the cementitous material is getting important issue onto road construction application. To elaborate this issue, according to our results, silica fume, high-ranged water reducer, viscosity agent, blast furnace slag were not enhanced much of dispersion characteristics of $TiO_2$ cluster. The combination of foaming agent and accelerator of hardening with viscosity agent and small grain size of fine aggregate may help the dispersion of $TiO_2$ inside cementitious materials. Even though the enhanced dispersion were applied to the specimen, NOx removal efficiency doest not change much for the top surface of the specimen. This concurrently affected by the presence of tiny air voids and the dispersion of $TiO_2$ in that these voids could easily adsorbed NOx gas with the aid of large surface area.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.3
• /
• pp.348-356
• /
• 2008

For the effective use of rainbow trout, the seasoned and dried rainbow trout slice (SR) was prepared and its characterization was compared with the commercial skipjack tuna (CSS) and pork products (CSP) by determining chemical components and sensory evaluation. The moisture content of SR, 20.5%, was lower, and the lipid content of SR, 7.5%, was higher than those of commercial products, CSS and CSP. The protein content of SR (41.4%) was higher than that of CSS (28.6%), but lower than that of CSP (50.1%). The water activity of SR was 0.654, which was lower than those of CSS and CSP, 0.724 and 0.771, respectively. According to the results, the color of SR was lower in lightness and redness and higher in browning index and ${\Delta}$E value than that of commercial products. The texture of SR was harder than that of CSS, but softer than that of CSP. According to the result of taste value, the taste of SR was stronger than that of CSP, while weaker than that of CSS. The mineral (Ca, P, and Fe), total amino acid contents, and the n-3/n-6 of SR showed significant levels in nutrition and health functional senses.

• KSBB Journal
• /
• v.25 no.6
• /
• pp.572-576
• /
• 2010

Biological products, such as live varicella vaccine, are composed of biological substances derived from biological organisms. It is very difficult to identify these biologics' characteristics by analysis of simple physical and chemical methods alone. So the reference material is essential in order to evaluate the quality of bilogics. The 1'st national standard for varicella live vaccine was manufactured, established in 2002 and 2003, and have been used for the manufacturer's quality control and national lot release since then. As the lack of its availability and the decrease of its stability, this study was initiated by National Institute of Food and Drug Safety Evaluation (NiFDS) in 2008 to manufacture and establish the 2nd national standard for varicella live vaccine. The candidate material was manufactured from one of domestic manufacterers and the joint research of the NiFDS and manufacturers of varicella live vaccine was conducted to estimate of the reliable virus content. In the collaborative study, 3 laboratories including NiFDS performed the virus content test more than 7 times and all assay results were statistically analyzed. The mean coefficient of variation (CV) was 1.24%, and the geometric mean titre (GMT) variation range of each laboratory was low. On the basis of the results of this study, the candidate material of 2nd national standard for varicella live vaccine was assigned a potency of 4.26 log10 pfu/0.5 mL, when reconstituted in 0.7 mL.

• The Journal of the Petrological Society of Korea
• /
• v.18 no.3
• /
• pp.223-236
• /
• 2009

Ultramafic xenoliths from southeastern part of Jeju Island can be grouped into two types: Type I and Type II. Type I xenoliths are magnesian and olivine-rich peridotite (mg#=89-91), which are commonly found at the outcrop. Most previous works have been focused on Type I xenoliths. Type II xenoliths, consisting of olivine, orthopyroxene and clinopyroxene with higher Fe and Ti components (mg#=77-83) and lower Mg, Ni, Cr, are reported in this study. They are less common with a more extensive compositional range. The studied Type II xenoliths are wehrlite, olivine-clinopyroxenite, olivine websterite, and websterite. They sometimes show ophitic textures in outcrops indicating cumulate natures. The textural characteristics, such as kink banding and more straight grain boundaries with triple junctions, are interpreted as the result of recrystallization and annealing. Large pyroxene grains have exsolution textures and show almost the same major compositions as small exsolution-free pyroxenes. Although the exsolution texture indicates a previous high-temperature history, all mineral phases are completely reequilibrated to some lower temperature. Orthopyroxenes replacing clinopyroxene margin or olivine indicate an orthopyroxene enrichment event. Mineral phases of Type II are compared with Type I xenoliths, gabbroic xenoliths, and the host basalts. Those from Type II xenoliths show a distinct discontinuity with those from Type I mantle xenoliths, whereas they show a continuous or overlapping relation with those from gabbroic xenoliths and the host basalts. Our petrographic and geochemical results suggest that the studied type II xenoliths appear to be cumulates derived from the host magma-related system, being formed by early fractional crystallization, although these xenoliths may not be directly linked to the host basalt.