• The Journal of the Petrological Society of Korea
• /
• v.14 no.1
• /
• pp.24-37
• /
• 2005

In this study we examined the geomorphological and geological characteristics of the granite landforms in the Iksan area. Moreover we investigated the source areas of stones which are used to build the Mieruksaji west stone pagoda. Joint is most identifiable geomorphological and geological structure in the Iksan area. Direction of J1 joint appears to be N71°E∼EW, and that of J2 joint ranges N20°W∼N20°E. Cross-pattern joint is predominant in the study area, and linen.-pattern vertical joint is also observed. Tor and corestone are easily found as geomorphological features in the study area. Corestones forming for are almost 2∼3 m across and 2∼3 m or over 5 m high. Their hardness is mainly of hammer bounce. Tower-type and castle-type of for are characteristic in the Mireuksan granites. Other geomorphological features such as tafoni, gnamma are also observed in the study area. Petrographical and geochemical features of the stones used for the Mireuksaji west stone pagoda are compared with those of the granites cropped out nearby, and indicate that the stones from the Mieruksaji west stone pagoda are quite similar to the Mireuksan granites. In the Mireuksan we can easily find lots of old traces for rock cutting.

• The Journal of the Petrological Society of Korea
• /
• v.6 no.2
• /
• pp.96-110
• /
• 1997

The Wondong Caldera, formed by the voluminous eruption of the rhyolitic ashflows of the Wondong Tuff which is about 1,550 m thick at the intracaldera and 550 m at the outflow, is a resurgent caldera which shows a dome structure on the central exposure of the caldera. The Wondong caldera volcanism eviscerated the magma chamber by a series of explosive eruptions during which rhyolitic magma was ejected, as small fallouts and voluminous ash-flows, to form the Wondong Tuff. The explosive eruptions began with ash-falls, progressed through pumice-falls and transmitted ash-flows. During the ash-flow phase the initial central vent eruption transmitted into late ring-fissure eruption which accompanied with caldera collapse. Contemporaneous collapse of the roop of the chamber resulted in the formation of the Wondong Caldera, a subcircular depression subsiding about 1,930 deep. Following the collapse, quartz porphyry was intruded as ring dykes along the ring fracture near the southwestern caldera rim. Subsequently the central part of the caldera floor began to be uplifted into a circular resurgent dome by the rising of residual magma. Concurrent with the resurgent doming, the volcaniclastic sediments of Hwajeri Formation were accumulated in the caldera moat and then rhyodacite lava erupted from the initial central resurgent dome and another ash-flow tuff from the northern ring fracture. After the sedimentation, the find-grained granodiorite was intruded as an arc along the eastern ring fracture of the caldera. Finally in the central part, the resurgent magma was emplaced as a hornblende biotite granite stock that formed the central dome.

• The Journal of the Petrological Society of Korea
• /
• v.25 no.1
• /
• pp.1-12
• /
• 2016

This study reports the results about the petrography of volcanic rocks in Namoo island and Namhyeongje island, off the southern coast of Busan City. The rocks in the Namhyeongje island composed of dacitic crystal-vitric welded tuff, showing phenocrysts of plagioclase, rock fragment with flow structure of elongated and flattened pumice fragments. In thin section it shows pyroclastic texture. The volcanic rocks in Namoo island are mainly dark grey-bluish dacite with phenocrysts of plagioclase and gradually changed to pink-greyish rhyodacite with auto-brecciated. In the northeastern part of the island, the volcanic rocks occurred as aggromerate with a poorly sorted mixture of blocks, lappili and ash and felsic feeder dike intrude the aggromerate. Major element composition of the volcanic rocks in Namhyeongje island and Namoo island are $SiO_2$ 73.6~74.4 wt.% and 65.5~68.3 wt.%, respectively. The volcanic rocks in these island are felsic volcanic rocks.

• The Journal of the Petrological Society of Korea
• /
• v.21 no.4
• /
• pp.397-403
• /
• 2012

Fe-REE deposits occurred in Jaeunri, Hongcheon formed by carbonatitic melts consist of 3 parts such as northern, middle and southern ore bodies showing discontinuous distribution, and extension shape of ore bodies can be figured through field survey and geometric analysis. Foliations in gneiss around northern and middle ore bodies represent NNE, whereas toward south its direction changes gradually from NE to ENE and finally N-S direction appears in southern ore body. From Jaeungyo to Saemaeulgyo geometric analysis from field work gives that fold shape in this area is open synclinal fold concavely and gently to NW with $45^{\circ}$ northwestward plunging axis, in contrast small scale anticline with $45^{\circ}$ northwestward plunging axis in Yagsooteo area near western part of Saemaeulgyo. Dragging effect could be occurred on these folds by WNW trending dextral strike-slip fault from Yagsooteo to Saemaeulgyo. New ore body can be confirmed from folding structure estimated by trend of foliation, and thus unidentified ore body may be exist under alluvial surface from middle to southern ore body and its distribution could show reversed "ㄱ", one of Korean consonants, considering with estimated strike and dip of foliations. This estimated extension of ore body figured out by structural analysis in the studied area works an important role for measuring of ore reserve and selecting of drilling site to find new ore body.

• Korean Journal of Optics and Photonics
• /
• v.28 no.1
• /
• pp.28-32
• /
• 2017

In this research, we designed an LSPR sensor based on a thin-film multilayer comprising $TiO_2$ and $SiO_2$. The thickness of the overall substrate layer of the suggested multilayer LSPR sensor is limited to 100 nm, and the number of repeating $TiO_2$ and $SiO_2$ thin films is 1-4 within a limited thickness. Additionally, a nanowire structure with a gold thin film of 40 nm, height of 40 nm, period of 600 nm, and line width of 300 nm was formed on the multilayer. To design the variable wavelength-type SPR, the angle was fixed at $75^{\circ}$ and the wavelength was changed. We then simulated the system with the finite-element method (FEM) using Maxwell's equations. It was confirmed that the resonance wavelength became shorter as the number of multilayers increased when the refractive index was fixed. We found that the wavelength changes were more sensitive. However, no changes were observed when the number of the multilayers was three or higher.

• Food Science and Preservation
• /
• v.22 no.6
• /
• pp.823-830
• /
• 2015

Physicochemical properties of five commercial rice products were investigated in order to select the appropriate rice varieties for the preparation of frozen fried rice. Among the evaluated rice varieties, Onnuri (16.06%) had the highest amylose content, while Beakjinju (11.83%) had the lowest. The water absorption index ranged from 1.45 to 1.65 g/g. Regarding the Hunter's color values, the L and a values of all rice varieties decreased while the b value increased with freezing-storage following the cooking process. The initial pasting temperature showed no significant differences among the five rice varieties. The highest viscosity (peak, trough, and final) and setback were found in the Sindongjin, while the lowest breakdown was found in the Baekjinju variety. Hardness, chewiness, and cohesiveness of all five cooked rice varieties decreased while their adhesiveness increased after freezing-storage. Under electron microscopy scanning, pores were observed inside the tissue of frozen cooked rices manufactured from Baekjinju and Hopum varieties, while substantially smooth tissue structure was observed in Sindognjin, Onnuri, and Ilmi rice varieties.

• Food Science and Preservation
• /
• v.22 no.6
• /
• pp.886-892
• /
• 2015

The antimicrobial effects of ten isothiocyanates (ITCs) present in cruciferous vegetables and radish root hydrolysate were investigated against pathogenic bacteria from olive flounder. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were measured against two gram-positive bacterial strains (Streptococcus parauberis, S. iniae) and four gram-negative bacterial strains (Edwardsiella tarda, Vibrio ichthyoenteri, V. harveyi, Photobacterium damselae) by using a broth microdilution technique. The antibacterial activity of ITCs was in the order sulforaphane > sulforaphene > phenylethyl ITC > erucin > benzyl ITC > iberin > I3C > allyl ITC > phenyl ITC > hexyl ITC. The susceptibility of fish pathogens to ITCs was in the order of V. harveyi > E. tarda > P. damselae > S. parauberis > S. iniae > V. ichthyoenteri. Antimicrobial activity (MIC) of radish root hydrolysate was 0.250 mg/mL against S. iniae, 0.438 mg/mL against S. parauberis, and 0.500 mg/mL against both E. tarda and V. harveyi. The aliphatic ITCs were potent inhibitors of the growth of fish pathogens, followed by aromatic ITCs and indolyl ITC. The presence of a double bond in the chemical structure of ITCs decreased antibacterial activity, while ITCs with a thiol (-S-) group and a longer carbon chain increased antibacterial activity. These results suggest that ITCs have strong antibacterial activities and may be useful in the prevention of fish pathogens.

• Food Science and Preservation
• /
• v.15 no.4
• /
• pp.532-541
• /
• 2008

A central composite design was applied to investigate the effects of the independent variables of NaOH concentration(X1) and extraction time(X2) on dependent variables such as Yield(Y1), Xyl/Ara ratio(Y2), uronic acid(Y3), $\beta$-glucan(Y4) and total sugars(Y5) of hemicelluloses separated from rice bran. The Coefficients of determination(R2) in various models ranged from 0.8626 to 0.9319. Yield increased with increased NaOH concentration and extraction time. The optimum extraction conditions were NaOH concentration at 2.45M and extraction time of 24.2 h. Predicted values at the optimized conditions were acceptable, compared with experimental values. The structural characteristics of an optimum hemicellulose extract were explored. As a result, it showed that the surfaces of hemicellulose had a highly irregular reticulated structure. And also it was both small and large molecular particle in the hemicelluloses. Their average molecular weights were in the ranges $235{\sim}240$ kDa and $8.0{\sim}9.4kDa$, respectively.

• Korean Journal of Plant Resources
• /
• v.24 no.2
• /
• pp.139-149
• /
• 2011

RAPD (random amplified polymorphic DNA) analysis was examined to detect variation of in vitro cultured 30 rhizomes of Cymbidium goeringii Lindley and Cymbidium kanran Makino, with long-term (8 years) subculture, respectively. Out of 151 DNA bands detected, the 40 were polymorphic with a polymorphic rate 26.4% in the C. goeringii. Out of 155 DNA bands detected, the 56 were polymorphic with a polymorphic rate 36.1% in the C. kanran. Genetic similarity matrix (GSM) shows from 0.825 to 1.00 with an average of 0.944 in the rhizomes of C. goeringii and 0.812 to 1.00 with an average of 0.913 in the C. kanran. According to the clustering analysis, C. goeringii was divided into 1 group and 2 independent individuals and its structure of clustering was simple than that of C. kanran. The higher polymorphism and the decreased GSM were showed in the long-term in vitro cultured C. goeringii and C. kanran supplemented with growth regulators. The results provide as fundamental data to develop a new materials for plant breeding and resources plant.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.4
• /
• pp.1081-1088
• /
• 2013

Two new metal-free organic dyes bridged by anthracene-mediated ${\pi}$-conjugated moieties were successfully synthesized for use in a dye-sensitized solar cell (DSSC). A N,N-diphenylthiophen-2-amine unit in these dyes acts as an electron donor, while a (E)-2-cyano-3-(thiophen-2-yl)acrylic acid group acts as an electron acceptor and an anchoring group to the $TiO_2$ electrode. The photovoltaic properties of (E)-2-cyano-3-(5-((10-(5-(diphenylamino)thiophen-2-yl)anthracen-9-yl)ethynyl)thiophen-2-yl)acrylic acid (DPATAT) and (E)-2-cyano-3-(5'-((10-(5-(diphenylamino)thiophen-2-yl)anthracen-9-yl)ethynyl)-2,2'-bithiophen-5-yl)acrylic acid (DPATABT) were investigated to identify the effect of conjugation length between electron donor and acceptor on the DSSC performance. By introducing an anthracene moiety into the dye structure, together with a triple bond and thiophene moieties for fine-tuning of molecular configurations and for broadening the absorption spectra, the short-circuit photocurrent densities ($J_{sc}$), and open-circuit photovoltages ($V_{oc}$) of DSSCs were improved. The improvement of $J_{sc}$ in DSSC made of DPATABT might be attributed to much broader absorption spectrum and higher molecular extinction coefficient (${\varepsilon}$) in the visible wavelength range. The DPATABT-based DSSC showed the highest power conversion efficiency (PCE) of 3.34% (${\eta}_{max}$ = 3.70%) under AM 1.5 illumination ($100mWcm^{-2}$) in a photoactive area of $0.41cm^2$, with the $J_{sc}$ of $7.89mAcm^{-2}$, the $V_{oc}$ of 0.59 V, and the fill factor (FF) of 72%. In brief, the solar cell performance with DPATABT was found to be better than that of DPATAT-based DSSC.