• Journal of the Mineralogical Society of Korea
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• v.22 no.4
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• pp.343-352
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• 2009

High-resolution Solid-state NMR provides element specific and quantitative information and also resolves, otherwise overlapping atomic configurations in multi-component non-crystalline silicates. Here we report the preliminary results on the effect of composition on the structure of CMAS (CaO-MgO-$Al_2O_3-SiO_2$) silicate glasses, as a model system for basaltic magmas, using the high-resolution 1D and 2D solid-state NMR. The $^{27}Al$ MAS NMR spectra for the CMAS silicate glasses show that four-coordinated Al is predominant, demonstrating that $Al^{3+}$ is network forming cation. The peak position moves toward lower frequency about 4.7 ppm with increasing $X_{MgO}$ due to an increase in $Q^4$(4Si) fraction with increasing Si content, indicating that Al are surrounded only by bridging oxygen. $^{17}O$ MAS NMR spectra for $CaAl_2SiO_6$ and $CaMgSi_2O_6$ glasses qualitatively suggest that NBO fraction in the former is smaller than that in $CaMgSi_2O_6$ glasses. As $^{17}O$ 3QMAS NMR spectrum of model quaternary aluminosilicate glass resolved distinct bridging and non-bridging oxygen environments, atomic structure for natural magmas can also be potentially probed using high-resolution 3QMAS NMR.

• Journal of the Korean Geographical Society
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• v.39 no.1
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• pp.27-44
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• 2004

Upper reach of Soyang River at the northernmost area around Taebaek Mountains in South korea is profitable area to understand paleo-environment during the Quaternary such as tectonic process and climate change in the Korean Peninsula. This study explained paleo-environment affect to channel development by geomorphic distribution and characteristics of terrace surfaces, and analysis of deposits at 58 fluvial terraces in upper reach of Soyang River. Fluvial terraces were classified from T1 to T6. Most terraces are distributed on the point bar in meandering channel and one side along river valley. Terraces tend to decrease in number and superficial dissection rate to be higher and channel slope to be steeper if it takes long time from T1 to 6. The paleo-channel of Soyang River is supposed to be stronger meandering in period of T2 than T3. The weathering rind of gravel is generally thicker in older terrace, however, differs by contents of water and air in deposits. Based on the data of stratigraphy, grain size analysis, pollen analysis and rubification index in deposit, formation age of T5 terrace in Soyang River are estimated in MIS(Marine Oxygen Isotope Stage) 10, and T2 terrace are estimated in MIS 6.

• BMB Reports
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• v.31 no.6
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• pp.595-599
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• 1998

To investigate conformational information of a low oxygen affinity recombinant hemoglobin (rHb) containing $96Val{\rightarrow}Trp$ mutation at the ${\alpha}96$ position, we ave produced rHb (${\alpha}96Val{\rightarrow}Phe$) and rHb (${\alpha}96Val{\rightarrow}Tyr$), using the Escherichia coli expression system and site-directed mutagenesis. The oxygen affinity of rHb (${\alpha}96Val{\rightarrow}Phe$) is similar to that of human normal adult hemoglobin (Hb A). However, the oxygen affinity of rHb (${\alpha}96Val{\rightarrow}Tyr$) showed much lower oxygen affinity than Hb A which is similar to that of rHb (${\alpha}96Val{\rightarrow}Tyr$), providing an opportunity as a potential candidate for a hemoglobin-based blood substitute. Both rHb (${\alpha}96Val{\rightarrow}Phe$) and rHb (${\alpha}96Val{\rightarrow}Tyr)$ showed high cooperativity in oxygen binding. IH-NMR spectroscopy shows that both rHb (${\alpha}96Val{\rightarrow}Phe$) and rHb (${\alpha}96Val{\rightarrow}Tyr$) have very similar tertiary structure around the heme pockets and uaternary structure in the ${\alpha}_1/{\beta}_2$ subunit interface ompared to Hb A. The low oxygen affinity of rHb (${\alpha}96Val{\rightarrow}Tyr$) has been suggested to be due to a hydrogen bond caused by an extra hydroxyl group not present in rHb (${\alpha}96Val{\rightarrow}Phe$). However, investigation of the carbonmonoxy form of rHb (${\alpha}96Val{\rightarrow}Phe$) and (${\alpha}96Val{\rightarrow}Try$) in the presence of inositol hexaphosphate at low temperature suggests that low oxygen affinity of (${\alpha}96Val{\rightarrow}Try$) may arise from a mechanism different to that of rHb (${\alpha}96Val{\rightarrow}Trp$).

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.1
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• pp.32-42
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• 2002

The late Quaternary deposit of Cheonsu Bay, up to 20 m in thickness above the Jurassic granite basement, consists of two sedimentary units: an upper Holocene mud and sandy mud deposit (Unit M1), and a lower late Pleistocene sand and mud deposit (Unit M2; 'Kanweoldo Deposit&apos). Unit M1 is a typical Holocene tidal-flat deposit of Cheonsu Bay, showing a coarsening upward, retrogradational facies trend. This retrograding facies trend is probably due to a relative low sedimentation rate during Holocene transgression. Overlain unconformably by Unit M1, Unit M2 deposit reaches up to 14 m in thickness and is mainly composed of muddy sediment with yellow to gray color. This unit is characterized by a variety of tide-influenced signatures such as rhythmic bedding, flaser bedding, crab burrow fossil, marine dinoflagellate assemblage and authigenic glauconite mineral, indicating very similar depositional environment to those of Unit M1 deposit. It suggests that Unit M2 was probably accumulated under the tidal-flat environment during a pre-Holocene sea-level highstand. In particular, the uppermost 3-4 m of Unit M2 appears to have undergone subaerial exposure and subsequent weathering during the sea-level lowstand after deposition. Therefore, stratigraphic unconformity between Holocene and late Pleistocene sediments is highlighted by the desiccated and weathered surface of Unit M2.

• Korean journal of applied entomology
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• v.59 no.4
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• pp.393-398
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• 2020

The blueberry gall midge, Dasineura oxycoccana (Johnson) (Diptera: Cecidomyiidae), is an emerging pest on cultivated blueberries in Korea. To develop a sensitive tool for monitoring this pest in blueberry orchards, we compared the attractiveness of host plant volatiles and sex pheromone to D. oxycoccana adults. We performed gas chromatography-mass spectrometry (GC-MS) analysis of solid-phase microextraction (SPME)-collected volatiles that were released from blueberry ('Darrow' cultivar). The analysis revealed two major volatiles, cinnamaldehyde and cinnamyl alcohol from flowers; and three major volatiles, β-caryophyllene, germacrene D, and α-farnesene from shoots and young fruits. In field tests conducted in Gunsan, Korea in 2019, commercialized cinnamaldehyde, cinnamyl alcohol, β-caryophyllene, and α-farnesene, used singly or in quaternary combination, were unattractive to the blueberry gall midge. However, traps baited with the known sex pheromone (2R,14R)-2,14-diacetoxyheptadecane attracted significantly more males than the treatments with plant volatiles or the control. No synergistic effect was observed between sex pheromone and plant volatiles. Male D. oxycoccana were captured in the pheromone traps from May to August, with three peaks in mid-May, late June, and late July in Gunsan blueberry fields in 2020.

• Economic and Environmental Geology
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• v.46 no.3
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• pp.267-278
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• 2013

The East African Rift System(EARS) is known to be hosted epithermal Au-Ag deposits, and the best-known example is Main Ethiopian Rift Valley(MER) related to Quaternary bimodal volcanism. Large horst-graben system during rifting provides open space for emplacement of bimodal magmas and flow channel of geothermal fluids. In recent, large hydrothermally altered zones(Shala, Langano, and Allalobeda) and hot spring related to deeply circulating geothermal water have been increasing their importance due to new discoveries in MER and Danakil depression. The hot springs in Shala and Allalobeda occur as boiling pool and geyser on the surface, whereas some areas didn't observe them due to decreasing ground water table. The host rocks are altered to quartz, kaolinite, illite, smectite, and chlorite due to interaction with rising geothermal water. The hot springs in MER are neutral to slightly alkaline pH(7.88~8.83) and mostly classified into $HCO_3{^-}$ type geothermal water. They are strongly depleted in Au, and Ag, but show a higher Se concentration of up to 26.7 ppm. In contrast, siliceous altered rocks around hot springs are strongly enriched in Pb(up to 33 ppm, Shala), Zn(up to 313 ppm, Shala), Cu(up to 53.1 ppm, Demaegona), and Mn(up to 0.18 wt%t, Shala). In conclusion, anomalous Se in hot spring water, Pb, Zn, Cu, and Mn in siliceous altered rocks, and new discoveries in MER have been increasing potential for epithermal gold mineralization.

• Analytical Science and Technology
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• v.11 no.6
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• pp.485-494
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• 1998

Ternary and quaternary alloys composed of Mo-Ru-Rh-Pd were prepared and their crystal structure and quantitative chemical compositions were analysed by XRD, WDX, EDX and ICP/AES. The results of X-ray diffraction studies showed that the alloys were crystallized in hexagonal close packing, well known as ${\varepsilon}$-phase with $P6_3/mmc$ of space group. The optimum accelerating voltage for Zr~Cd(40~48) analyzed by EPMA using PET crystal was found to be 15 kV and the linear regression coefficient(R) of atomic number and X-ray intensity was approximately 0.998 without Tc standard specimen. The WDX results of alloys of Mo and Pd by linear regression equations were detected to be 0.1% lower compared to WDX analysis results using standard specimen, while Ru, Rh were detected 3% higher. These alloys were completely dissolved in mixed acid of 12.5 mL HCl and 1 mL $HNO_3$, at $220^{\circ}C$ for 22 hours using autoclave with PTFE vessel. There was no reprecipitating phenomnon when diluted 100 times with 1N-HCl. The results of ICP/AES analysis deviated less than 4% comparing with those of normal WDX analysis.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.954-961
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• 2002

Extracts of raw bloody clams, broughton's ribbed ark (Scaphrca broughtonii), subcrenated ark (S. subcrenata), and granulated ark (Tegillarca granosa), were analyzed and compared foe extractive nitrogen, free amino acids, combined amino acids, ATP and related compounds, quaternary ammonium bases, and guanidino compounds. The contents of extractive nitrogen in broughton's ribbed ark, subcrenated ark, and granulated ark were 479, 506, and 432 mg/100 g, respectively. Twenty-eight or twenty-nine types of free amino acids were detected in all three extracts, among which taurine, ${\beta}-alanine$, glutamic acid, and alanine were the major ones. The composition of the major extractive components such as free amino acids, combined amino acids, ATP and related compounds, TMAO, TMA, and creatine in the extracts were similar among the extracts, but their contents were different.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.1
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• pp.35-44
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• 2022

The V_S30 map is used as a key variable for site amplification in the ShakeMap, which predicts ground motion at any site. However, no V_S30 map considering Korean geology and geomorphology has been developed yet. To develop a proxy-based V_S30 map, we used 1,101 V_S profiles obtained from a geophysical survey and collected proxy layers of geological and topographical information for the Korean Peninsula. Then, V_S30 prediction models were developed using linear regression analysis for each geological age considering the distribution of V_S30. As a result, models depending on geomorphology were suggested per each geologic group, including Quaternary, Fill, Ocean, Mesozoic group and Precambrian. Resolution of map is doubled from that of V_S30 map by U.S. Geological Survey (USGS). Standard deviation of residual in natural log of proxy-based V_S30 map is 0.233, whereas standard deviation of slope-based USGS V_S30 map is 0.387. Therefore, the proxy-based V_S30 map developed in this study is expected to have less uncertainty and to contribute to predicting more accurately the ground motion amplitude.

• 한국해양학회지
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• v.26 no.3
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• pp.193-203
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• 1991

KODOS (Korea Deep ocean Study)-89 sediments, recovered from western part of Clarion-Clipperton fracture zone in north Pacific, show two distinctly colored layer zones: surface yellow brown layer (unit A) and subsurface dark brown layer (unit B), and roughly recognized as Quaternary and Tertiary in age, respectively. Geochemical characteristics are also different in those two units. Smectite, water, micronodule, and heavy metal contents are higher in unit B, while POC content is higher in unit A. High smectite and low POC contents in unit B are due to the longer formation period of smectite, almost decomposition of labile organic matter in unit B relative to unit A. High water content in unit B is caused by coarse fabric which results from higher content of spicules and spines. Additionally, stronger electrostatic repulsion force caused by high smectite content also supports high water content in unit B relative to unit A. Variations in heavy metal contents are closely related to the amount of micronodule, which has higher metal contents than that of sediment. Therefore, we conclude that the differences of geochemical characteristics in unit A and unit B are resulted from the different diagenetic durations of unit A and unit B.