• The Journal of Engineering Geology
• /
• v.13 no.1
• /
• pp.83-105
• /
• 2003

Geochemical studies on the alluvial aquifer system near the Nakdong River were carried out for the basic investigation of the estimation of artificial recharge for the river bank filtration. In-situ data do not show any distinct difference between the pumping well and river. Most of waters belong to $_3$ and Ca-$SO_4$ types and show high Mn concentration. In the borehole installed with Multi-Ca-HCOPacker (MP) system, Na, Ca, Mg, $HCO_3$ contents of the groundwater are increased with depth increasing. Cl and $SO_4$ contents of the groundwater show the lowest values at the bottom level (18m depth) and Mn content is very high at the middle level (13.5 m depth) of MP system. There is no distinct difference in the ${\delta}^{18}O$ and D values and tritium content between MP, borehole and surface water samples. The sulfur isotope data indicate that the possible sulfur source is dissolution of sulfate mineral from sedimentary rock. Strontium isotope ratio shows a little differences between the pumping well and observation borehole samples. Nitrogen isotope data indicate that the nitrogen of water samples is originated from fertilizer or organic materials.

• Korean Journal of Food Science and Technology
• /
• v.49 no.3
• /
• pp.235-241
• /
• 2017

Generally, peanuts are classified as high-fat foods as they possess high proportions of fatty acids. This study compared lipid constituents and properties between normal and high-oleic peanuts. Gas Chromatography-Flame Ionization Detector (GC-FID) analyses revealed that the fatty acid levels were significantly different between the normal and higholeic peanuts (p<0.05). Eight fatty acids were identified in the samples, including palmitic (C16:0), stearic (C18:0), oleic (C18:1, n9), linoleic (C18:2, n6), arachidic (C20:0), gondoic (C20:1, n9), behenic (C22:0), and lignoceric (C24:0) acids. Four tocopherol homologs were detected, and ${\alpha}$- and ${\gamma}$-tocopherols were the predominant ones. Tocopherols were rapidly decomposed during 25 day storage at $80^{\circ}C$. The main identified phytosterols were beta-sitosterol, ${\Delta}^5$-avenasterol, campesterol, and stigmasterol. Acid and peroxide values indicated that high-oleic peanuts have better oxidative stability than normal peanuts. These results can serve as the basis for the use of peanuts in the food industry.

• 한국해양학회지
• /
• v.29 no.2
• /
• pp.164-170
• /
• 1994

The well preserved ostracodes of the Chunbuk Formation in Pohang Basin were analyzed isotopically to understand paleoceanographic conditions of the southeastern park of Korean peninsula which Songhacdong, and Mulcheonri areas range from - 2.2 to - 0.7% (PDB), - 0.7 to 0.0% , and -20.0 to - 0.8%, and their corresponding paleotemperatures range from ca 20 to 27$^{\circ}C$ (average = 24$^{\circ}C$), 17 to 20$^{\circ}C$ (average = 18$^{\circ}C$), and 20 to 26$^{\circ}C$ (average=23$^{\circ}C$),respectively. Assuming the $\delta$/SUP 18/O composition of the Middle Miocene seawater was about - 0.34% (SMOW), the paleotemperatures of the Middle Miocene shallow seawater in the Pohang Basin was almost equal to or slightly higher than the present summer temperature (ca 16 to 20$^{\circ}C$) near Pohang area. Carbon isotopic value of Cyhere omotenipponica is - 0.8% (PDB), reflecting marine carbonate carbon composition. Carbon isotopic compositions of other ostracodes such as Aurial okumurai, Trachyleberis niitsmai, Urocythereis sp., Urocythereis cf. gorokuensis, and Acanthocythereis mutsuensis range from - 5.2 to - 3.4% (PDB), which might have secreted their shells out of equilibrium with ambient seawater. This disequilibrium was most likely to have resulted from metabolic (=vital) effect, rather than temperature of productivity.

• Economic and Environmental Geology
• /
• v.34 no.1
• /
• pp.25-38
• /
• 2001

Contrasts in the style of the gold-silver mineralization in geologic and tectonic settings in Korea, together with radiometric age data, reflect the genetically different nature of hydrothermal activities, coinciding with the emplacement age and depth of Mesozoic magmatic activities. It represents a clear distinction between the plutonic settings of the Jurassic Daebo orogeny and the subvolcanic environments of the Cretaceous Bulgugsa igneous activities. During the Daebo igneous activities (about 200-130 Ma) coincident with orogenic time, gold mineralization took place between 197 and 127 Ma. The Jurassic deposits commonly show several characteristics: prominent association with pegmatites, low Ag/Au ratios in the ore-concentrating parts, massive vein morphology and a distinctively simple mineralogy including Fe-rich sphalerite, galena, chalcopyrite, Au-rich eIectrum. pyrrhotite and/or pyrite. During the Bulgugsa igneous activities (120-60 Ma), the precious-metal deposits are generally characterized by such features as complex vein morphology, medium to high AgiAu ratios in the ore concentrates, and abundance of ore minerals including base-metal sulfides, Ag sulfides, native silver, Ag sulfosalts and Ag tellurides. Vein morphology, mineralogical, fluid inclusion and stable isotope results indicate the diverse genetic natures of hydrothermal systems. The Jurassic Au-dominant deposits were formed at the relatively high temperature (about 300 to 450$^{\circ}$C) and deep-crustal level (>3.0 kb) from the hydrothermal fluids containing more amounts of magmatic waters (3180; 5-10 %0). It can be explained by the dominant ore-depositing mechanisms as CO2 boiling and sulfidation, suggestive of hypo/mesothermal environments. In contrast, mineralization of the Cretaceous Au-Ag type (108-71 Ma) and Agdominant type (98-71 Ma) occurred at relatively low temperature (about 200 to 350$^{\circ}$C) and shallow-crustal level «1.0 kb) from the ore-fonning fluids containing more amounts of less-evolved meteoric waters (15180; -10-5%0). These characteristics of the Cretaceous precious-metal deposits can be attributed to the complexities in the ore-precipitating mechanisms (mixing, boiling, cooling), suggestive of epilmesothermal environments. Therefore, the differences of the emplacement depth between the Daebo and the Bulgugsa igneous activities directly influence the unique temporal and spatial association of the deposit type.

• Economic and Environmental Geology
• /
• v.36 no.4
• /
• pp.257-268
• /
• 2003

The Cretaceous magmatism in the Gyeongsang Basin, Korea, led to the formation of two contrasting metallogenic provinces: the Haman-Gunbug-Goseong(-Changwon) (HGGC) and the Euiseong (EU). The mineralization in the HGGC metallogenic province represents copper, gold and iron of porphyry-related deposits that display close relationships in time and space with subvolcanic granitoids. Much of copper-gold-forming events in this province are consistently constrained to the period between ca. 89 and 81 Ma. The hydrothermal systems of copper-gold vein deposits in the HGGC province are associated with ore-forming fluids of high to intermediate temperature (300∼50$0^{\circ}C$) with high salinity (20∼55 equiv. wt. % NaCl). The ore-forming fluids become progressively more diluted by the incorporation of decreased quantities of magmatic water further from the nearby intrusion, suggesting significant input and fluid mixing of a meteoric water component to the magmatic fluids during the late stage of geothermal systems. In contrast, the EU metallogenic province is characterized by polymetallic vein deposits that are consistently constrained to a period of 78∼60 Ma. The geothermal systems of polymetallic vein deposits in the EU province are derived from a narrow range of intermediate temperature (200∼40$0^{\circ}C$) with relatively low salinity(1∼7 equiv. wt.% NaCl). It may represent a mixed fluid of magmatic and meteoric waters. The base-metal mineralization in the Gyeongsang Basin shows a close spatial and temporal distinction between the proximal environment derived from shallow-level granitoids in the southwestern HGGC province and the distal condition derived from volcanic environments in the northwestern EU province.

• Journal of the Korean Chemical Society
• /
• v.33 no.3
• /
• pp.287-294
• /
• 1989

The optimum condition for the separation of priority pollutant phenols using isocratic elution has been determined. The elution behavior of eleven phenols has been also studied to interpret the retention. The reversed phase liquid chromatographic methods were performed on a ${\mu}$-Bondapak $C_{18}$ column with methanol-water, acetonitrile-water, and THF water mixtures as mobile phases. The COF method, where Snyder's solvent triangle concept was combined with a mixture-design statistical technique, was used to optimize the strength and selectivity of solvents for the separation of phenols. The optimum solvent composition, which gives a complete separation of eleven phenols, was found to be $MeOH:ACN:H_2O$ = 7:40:53. The plots of ln k' vs. -${\Delta}H^{\circ}$ and ${\Sigma}{\pi}$ of phenols showed relatively good linearities. Effect of van der Waals volume, pi-energy and hydrogen bonding on the retention of phenols were investigated. The following equation with the correlation coefficient of 0.9927 for ACN-water solvent system was obtained; $log^{k'}=2.515{\times}10^{-2}VWV-1.301{\times}10^{-1}E-3.674{\times}10^{-1}$

• Economic and Environmental Geology
• /
• v.31 no.3
• /
• pp.201-213
• /
• 1998

From the Jungwon and Munkyeong areas which are among the famous producers of the carbonate-type groundwaters in Korea, various kinds of natural waters (deep groundwater, shallow groundwater and surface water) were collected between 1996 and 1997 and were studied for hydrogeochemical and environmental isotope (${\delta}^{34}S_{so4}$, ${\delta}^{18}O$, ${\delta}D$)systematics. Two types of deep groundwaters (carbonate type and alkali type) occur together in the two areas, and each shows distinct hydrogeochemical and environmental isotope characteristics. The carbonate type waters show the hydrochemical feature of the 'calcium(-sodium)-bicarbonate(-sulfate) type', whereas the alkali type water of the 'sodium-bicarbonate type'. The former type waters are characterized by lower pH, higher Eh, and higher amounts of dissolved ions (especialJy, $Ca^{2+}$, $Na^{+}$, $Mg^{2+}$, $HCO_3{^-}$ and $SO_4{^{2-}}$). Two types of deep groundwaters are all saturated or supersaturated with respect to calcite. Two types of deep groundwaters were both derived from pre-thermonuclear (about more than 40 years old) meteoric waters (with lighter 0 and H isotope data than younger waters, i.e., shallow cold groundwaters and surface waters) which evolved through prolonged water-rock interaction. Based on the geologic setting, water chemistry, and environmental isotope data, however, each of these two different types of deep groundwaters represents distinct hydrologic and hydrogeochemical evolution at depths. The carbonate type groundwaters were formed through mixing with acidic waters that were derived from dissolution of pyrites in hydrothermal vein ores (for the Jungwon area water) or in anthracite coal beds (for the Munkyeong area water). If the deeply percolating meteoric waters did not meet pyrites during the circulation, only the alkali type groundwaters would form. This hydrologic and hydrogeochemical model may be successfully applied to the other carbonate type groundwaters in Korea.

• Economic and Environmental Geology
• /
• v.28 no.4
• /
• pp.337-350
• /
• 1995

The Hwacheon-ri mineralized area is located within the Cretaceous Gyeongsang Basin of the Korean peninsula. The mineralized area includes the Hwacheon, Daeweon, Kuryong and Cheongryong mines. Each of these mines occurs along copper-bearing hydrothermal quartz veins that crosscut late Cretaceous volcanic rocks, although some disseminated ores in host rocks also exist locally. Mineralization can be separated into three distinct stages (I, II, and III) which developed along preexisting fracture zones. Stage I is ore-bearing, whereas stages II and III are barren. The main phase of ore mineralization, stage I, can be classified into three substages (Ia, Ib and Ic) based on ore mineral assemblages and textures. Substage Ia is characterized by pyrite-arsenopyrite-molybdenite-pyrrhotite assemblage and is most common at the Hwacheon deposit. Substage Ib is represented by main precipitation of Cu, Zn, and Pb minerals. Substage Ic is characteristic of hematite occurrence and is shown only at the Kuryong and Cheongryong deposits. Some differences in the ore mineralization at each mine in the area suggest that the evolution of hydrothermal fluids in the area varied in space (both vertically and horizontally) with respect to igneous rocks relating the ore mineralization. Fluid inclusion data show that stage I ore mineralization mainly occurred at temperatures between ${\approx}350^{\circ}$ and ${\approx}200^{\circ}C$ from fluids with salinities between 9.2 and 0.5 wt.% eq. NaCl. In the waning period of substage Ia, the high temperature and salinity fluid gave way to progressively cooler, more dilute fluids of later substage Ib and Ic (down to $200^{\circ}C$, 0 wt.% NaCl). There is a systematic decrease in the calculated ${\delta}^{18}O_{H2O}$ values with paragenetic time in the Hwacheon-ri hydrothermal system from values of ${\approx}2.7$‰ for substage Ia, through ${\approx}-2.8$‰ for substage Ib, to ${\approx}-9.9$‰ for substage Ic. The ${\delta}D$ values of fluid inclusion water also decrease with decreasing temperature (except for the Daeweon deposit) from -62‰ (substage Ia) to -80‰ (substage Ic and stage III). These trends are interpreted to indicate the progressive cooler, more oxidizing unexchanged meteoric water inundation of an initial hydrothermal system which is composed of highly exchanged meteoric water. Equilibrium thermodynamic interpretation of the mineral assemblages with the variation in amounts of chalcopyrite through the paragenetic time, and the evolution of the Hwacheon-ri hydrothermal fluids indicate that the solubility of copper chloride complexes in the hydrothermal system was mainly controlled by the variation of temperature and $fo_2$ conditions.

• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.7
• /
• pp.445-453
• /
• 2012

An investigation for removal of 1-indanone (1-ID), which were commonly produced from the biological and/or chemical treatment and natural weathering of the PAHs-contaminated soils, via oxidative transformation mediated by birnessite in the presence of various phenolic mediators is described. This study also examines the potential effect of the natural occurring substance humic acid (HA) on the oxidative transformation. The experiment was carried out in aqueous phase as a batch test (10 mg/L 1-ID, 0.3 mM phenolic mediators, $1.0g/L\;{\delta}-MnO_2$, at pH 5). All of the 11 tested phenoilic mediators belong to the group of natural occurring phenols and are widely used as model constituents of humic substances. From the results of HPLC analysis, it is demonstrated that 1-ID was not reactive to birnessite itself, but it can be effectively removed in birnessite-mediated cross coupling reactions in the presence of the phenolic mediators. The percent removals of 1-ID after 2 day incubation were ranged from 9.2 to 71.2% depending on the phenolic mediators applied. The initial rate constant ($K_{int}$, $hr^{-1}$) values for the 1-ID removals obtained from the pseudo-first-order kinetic plots also widely ranged from 0.18 to 15.0. Results of the correlative analysis between the removal efficiencies and structural characteristics of phenolic mediators indicate that the transformation of the 1-ID was considerably enhanced by the addition of electron-donating substituents (e.g., -OH, $-OCH_3$) at the benzne ring, and much less enhanced by the addition of electron-withdrawing substituents (e.g., -COOH, -CHO). The presence of HA showed that removal efficiencies of 1-ID in the birnessite-phenolic mediator systems decreased with increasing HA concentrations. However at low concentration of HA (< 2 mg/L), it caused some enhancement in the removals of 1-ID as compared to the control.

• Korean Journal of Food Science and Technology
• /
• v.33 no.6
• /
• pp.737-744
• /
• 2001

This study was carried to investigate the changes in physical and chemical properties during preparation of Yukwa. Protein content of glutinous rice was decreased during soaking time and acid and pH values were increased while contents of lipid and ash were not changed. Particle size distribution showed thate average particle size of 7 days soaking treatment smaller than those of 3 days and starch damage of glutinous rice flour was increased during soaking time. The major flavor components after soaking were found ethyl ester acetic acid, ethanol, 2-butan -ol, 2-methyl 1-propanol, 1-butanol, 3-methyl 1-butanol and 1-pentanol, propanoic acid. Content of acetic acid and butanoic acid were rapidly increased during soaking time. Results for ratio of storage modulus(G') and loss modulus(G') in glutinous rice flour dough indicated $tan{\delta}$ was increased for a while and decreased as frequency increased. G' value was very similar with G' value after steaming which means rubber-like property while G' and G' value were changed after during storage time. Treatment at $-20^{\circ}C$ had the highest hardness for cutting degree of dough. There was no difference in color value between different water contents. Hardness of Bandegi (sheet) was decreased as water content increased and the highest popping value was obtained at 18% of water contents. Adding 3% soaked bean had higher redness value of Yukwa and lower value in yellowness.