• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.495-497
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• 2015

Galaxies can be "pre-processed" in the low-density outskirts by ambient medium in the filaments or tidal interactions with other galaxies while falling into the cluster. In order to probe how early on and by which mechanisms galaxies can be affected before they enter high-density cluster environments, we are carrying out an atomic hydrogen ($H\small{I}$) imaging study of a sample of galaxies selected from three filamentary structures around the Virgo cluster. Our sample consists of 14 late-type galaxies, which are potentially interacting with their surroundings. The $H\small{I}$ observations have been done using the Westerbork Synthesis Radio Telescope, the Giant Metrewave Radio Telescope, and the Jansky Very Large Array with column density sensitivity of ${\approx}3-5{\times}10^{19}cm^{-2}$ in $3{\sigma}$ per channel, which is low enough to detect faint $H\small{I}$ features in the outer disks of galaxies. In this work, we present the Hi data of two galaxies that were observed with GMRT. We examine the $H\small{I}$ morphology and kinematics to find the evidence for gas-gas and/or tidal interactions, and discuss which mechanism(s) could be responsible for pre-processing in these cases.

• The Journal of Korean Obstetrics and Gynecology
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• v.18 no.1
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• pp.15-28
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• 2005

To address the ability of Kung-Kyung-Ilho-Jeon(KK) to induce cell death, we investigated the effect of KK on cell viability. Forty-eight hours later, loss of viability occurred following KK exposure in a dose-dependent manner. The treatment of KK, a commonly used herb formulation in Korea and China, caused a decrease in cell viability. KK also resulted in apoptotic morphology a brightly blue-fluorescent condensed nuclei by Hoechst 33258-staining, and reduction of cell volume. Our results show that KK induces caspase-3 and -9 activation in a time-dependent manner. In addtion, the translocation of cytochrome c release into cytoplasm has been observed under the presence of $5mg/m{\ell}$ KK. The subsequent loss of mitochondria membrane potential is collapsed by the addition of KK. Our immunoblotting data show that PARP, a well known caspase-3 and -6 substrate, is cleaved by KK. We show that a pro-apoptotic protein, Bax is increased in the presence of KK but that the amount of Bcl-2 is not changed. We suggest that Bax, a critical protein which can regulate channel of mitochondria to release cytochrome c, is a key protein in KK-induced apoptosis of Hela human cervical carcinoma cells

• Electronic Materials Letters
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• v.14 no.6
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• pp.669-677
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• 2018

In this work, the high ${\kappa}$ $Zr_xAl_{1-x}O_y$ films with a different Zr concentration have been deposited by atomic layer deposition, and the effect of Zr concentrations on the structure, chemical composition, surface morphology and dielectric properties of $Zr_xAl_{1-x}O_y$ films is analyzed by Atomic force microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and capacitance-frequency measurement. The effect of Zr concentrations of $Zr_xAl_{1-x}O_y$ gate insulator on the electrical property and stability under negative bias illumination stress (NBIS) or temperature stress (TS) of ZnSnO (ZTO) TFTs is firstly investigated. Under NBIS and TS, the much better stability of ZTO TFTs with $Zr_xAl_{1-x}O_y$ film as a gate insulator is due to the suppression of oxygen vacancy in ZTO channel layer and the decreased trap states originating from the Zr atom permeation at the $ZTO/Zr_xAl_{1-x}O_y$ interface. It provides a new strategy to fabricate the low consumption and high stability ZTO TFTs for application.

• Membrane Journal
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• v.29 no.5
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• pp.252-262
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• 2019

A sulfonated star branched poly(styrene-b-butadiene-b-styrene) triblock copolymer (SSBS) was synthesized with varying degrees of sulfonation. The effective sulfonation on the butadiene block was confirmed by FT-IR spectroscopy. Ion exchange capacity by titration was used to determine the degree of sulfonation. The synthesized polymer observed enhanced water uptake and proton conductivity. At room temperature, the SSBS with 25 mol% degree of sulfonation showed an outstanding proton conductivity of 0.114 S/cm, similar to that of commercial membrane, Nafion. The effect of temperature at constant relative humidity on conductivity resulted to a remarkable increase in proton conductivity. Methanol permeability studies showed a value lower than Nafion for all the sulfonated membranes. Structural nature observed using AFM showed that the membranes observed microphase separated nanostructures and the connectivity of the interionic channels.

• Korean Journal of Metals and Materials
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• v.49 no.2
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• pp.112-120
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• 2011

The out-of-phase thermo-mechanical fatigue (OP TMF) in a <001> oriented single crystal nickel-based superalloy CMSX-4 has been studied. OP TMF life was less than a half of low cycle fatigue(LCF) life in spite of a small hysteresis loop area of OP TMF compared to that of LCF. The failure was caused by the initiation of a crack at the oxide-layered surface followed by its planar growth along the <100> ${\gamma}$ channel in both LCF and OP TMF. However, deformation twins appeared near the major crack of OP TMF. The multiple groups of parallel twin plates on {111} planes provided a preferential path for crack propagation, which caused a significant decrease in OP TMF life. Additionally, the analysis on the surface crack morphology revealed that the tensile strain at the minimum temperature of OP TMF was found to accelerate the crack propagation.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1519-1526
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• 2023

For the first time Aluminium-BariumeZinc oxide nanocomposite (ZABONC) was synthesized by solution combustion method where calcination was carried out at low temperatures (600℃) to study the electromagnetic (EM) (X/γ) radiation shielding properties. Further for characterization purpose standard techniques like PXRD, SEM, UV-VISIBLE, FTIR were used to find phase purity, functional groups, surface morphology, and to do structural analysis and energy band gap determination. The PXRD pattern shows (hkl) planes corresponding to spinel cubic phase of ZnAl₂O4, cubic Ba(NO₃)₂, α and γ phase of Al₂O₃ which clearly confirms the formation of complex nano composite. From SEM histogram mean size of nano particles was calculated and is in the order of 17 nm. Wood and Tauc's relation direct energy band gap calculation gives energy gap of 2.9 eV. In addition, EM (X/γ) shielding properties were measured and compared with the theoretical ones using standard procedures (NaI (Tl) detector and multi channel analyzer MCA). For energy above 356 keV the measured shielding parameters agree well with the theory, while below this value slight deviation is observed, due to the influence of atomic/crystallite size of the ZABONC. Hence synthesized ZABONC can be used as a shielding material in EM (X/γ) radiation shielding.

• Journal of the Korean association of regional geographers
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• v.12 no.4
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• pp.449-460
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• 2006

This study aims to analyze distribution of natural lakes including lagoonal lake(lagoon) and tributary dammed lake(tributary lake) and calculate the size, morphology in order to interpret time-serial change of lakes using methodology of remote sensing images(1990s), GIS and topographic maps(1920s) in east coast of Korean Peninsular. Analysis results show that in 1990s, there are 57 natural lakes, with the total size of $75.62km^2$ over size $0.01km^2$. marine-origin lagoons are 48 with total size of $64.85km^2$, composing 85% of total natural lake, and the largest lagoon is Beonpo in Raseon City. Tributary lakes have been formed by damming of tributary channels by fluvial sand bars from main stream, located nearby at coastal zone, similar to lagoon sites. Large tributary lake, Jangyeonho, is developed in lava plateau dissection valley of Eorang Gun, Hamnam Province. There are more distributed at Duman River mouth$\sim$Cheongjin City, Heungnam City$\sim$Hodo Peninsular and Anbyeon Gun$\sim$Gangreung City. Geomorphometrically, correlation of size to circumference is very high, but correlation of size to shape irregularity is very low. The direction of lagoonal coast, NW-SE and NE-SW are predominated due to direction of tectonic structure and longshore currents. The length of the river into lake are generally short, maximum under 15km, and lake size is smaller, degree of size decreasing is higher. Geomorphic patterns of the lake location are classified as coast-hill range, coastal plain, coastal plain-channel valley, coastal plain-hill range and channel valley-hill range. During from 1920s to 1990s, change with lake size decreasing is highest at coastal plain-channel valley, next is coastal plain. Causes of the size decreasing are fluvial deposition from upper rivers and human impacts such as reclamation.

• Korean Journal of Digital Imaging in Medicine
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• v.15 no.2
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• pp.63-68
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• 2013

Purpose : The relaxation times of tissue in MRI depend on strength of magnetic field, morphology of nuclear, viscosity, size of molecules and temperature. This study intended to analyze quantitatively that materials' temperatures have effects on T1 and T2 relaxation times without changing of other conditions. Materials and Methods : The equipment was used MAGNETOM SKYRA of 3.0T(SIEMENS, Erlagen, Germany), 32 channel spine coil and Gd-DTPA water concentration phantom. To find out T1 relaxation time, Inversion Recovery Spin Echo sequences were used at 50, 400, 1100, 2500 ms of TI. To find out T2 relaxation time, Multi Echo Spin Echo sequences were used at 30, 60, 90, 120, 150, 180, 210, 240, 270 ms of TE. This experiment was scanned with 5 steps from 25 to $45^{\circ}C$. next, using MRmap(Messroghli, BMC Medical Imaging, 2012) T1 and T2 relaxation times were mapped. on the Piview STAR v5.0(Infinitt, Seoul, Korea) 5 steps were measured as the same ROI, and then mean values were calculated. Correlation between the temperatures and relaxation times were analyzed by SPSS(version 17.0, Chicago, IL, USA). Results : According to increase of temperatures, T1 relaxation times were $214.39{\pm}0.25$, $236.02{\pm}0.87$, $267.47{\pm}0.48$, $299.44{\pm}0.64$, $330.19{\pm}1.72$ ms. T2 relaxation times were $180.17{\pm}0.27$, $197.17{\pm}0.44$, $217.92{\pm}0.39$, $239.89{\pm}0.53$, $257.40{\pm}1.77$ ms. With the correlation analysis, the correlation coefficients of T1 and T2 relaxation times were statistically significant at 0.998 and 0.999 (p< 0.05). Conclusion : T1 and T2 relaxation times are increased as temperature of tissue goes up. In conclusion, we suggest to recognize errors of relaxation time caused local temperature's differences, and consider external factors as well in the quantitative analysis of relaxation time or clinical tests.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.6
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• pp.474-481
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• 2004

Squamous cell carcinoma is the most prevalent oral cancer, which is characterized by its low survival rate, high malignancy, mortality with facial defects, and poor prognosis. Exact cause and pathogenesis of the squamous cell carcinoma is still unknown. Various routes including smoking, radiation, and viral infections predispose its genesis, and recent studies revealed that genetic defects which fail to prevent cancer proliferation play a role. Generally, a cancer develops from the decreased rate of apoptosis which is an active and voluntary cell death, and from the altered cell cycles. Anticancer effect can be obtained by recovering the apoptotic process, and by suppressing the cell cycles. Among the apoptosis related factors, bcl-2, caspase-9, and VDAC (voltage-dependent anion channel)are produced in mitochondria of the cell. Cyclosporin-A is known to induce apoptosis through its activation with VDAC. This study was to reveal the anticancer effect of Cyclosporin A to the oral squamous cell carcinoma. The inverted microscope was used to find alterations in the tissue, and sensitivity test to the anticancer cells was performed with MTT (Tetrazolium-based colorimetric) assay. Following cell line culture of primary and metastastic oral squamous cell carcinoma, electrophoresis was performed with extracted total RNA. Finally, semi-quantitative study was carried out through RT-PCR (Reverse Transcription-Polymerase Chain Reaction). The results of this study are as follows: 1. The inverted microscopic observation revealed a poorly defined cytoplasm at $2000ng{\sim}3000ng/ml$, indistinct nucleus, and apoptosis. 2. The Growth of cancer cells was decreased at 1000ng/ml of cyclosporin-A. No cancer cell growth was observed at over 2000ng/ml concentration of cyclosporin-A, and at one week, growth of cancer cells was ceased. 3. The MTT assays were decreased as cyclosporin-A concentration was increased. This means that the activation of succinyl dehydrogenase in mitochondria was decreased following administration of cyclosporin A. 4. A result of RT-PCR showed that amount of mRNA of VDAC-2 was decreased half times at a cyclosporine-A concentration of 2000ng/ml. In bcl-2, amount of mRNA was significantly decreased 1/5 times at 2000ng/ml. caspase-9, however, showed slight increase compared to the control group. From the results obtained in this study, administration of cyclosporin-A to the cell lines of oral squamous cell carcinoma induced alterations in morphology and growth of the cells as its concentration increased. Since apoptosis related factors such as VDAS-2, bcl-2, and caspase-9 also showed distinct alterations on their mRNAs, further research on cyclosporin A as an anti-cancer agent will be feasible.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.1
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• pp.141-148
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• 2012

The objective of this study is to remove arsenate from artificially contaminated wastewater using CaAl-ettringite and CaAl-monosulfate which were synthesized in laboratory. The study was carried on the basis of solidification/stabilization of waste using cement. Monosulfate and ettringite are constituents of cement paste. The CaAl-ettringite has a chemical formula of $Ca_6Al_2O_6(SO_4)_3{\cdot}32H_2O$ and has a needle like morphology. Whereas CaAl-monosulfate $Ca_4Al_2O_6(SO_4){\cdot}12H_2O$ has layered double hydroxide structure (LDH) in which the mainlayer consists of Ca and Al and S as interlayer. Ettringite and monosulfate were synthesized by reaction of tricalcium aluminate and gypsum and hydrating this mixture at elevated temperature. The synthesized mineral were characterized by PXRD and FESEM to ensure purity. It was found that concentrations of As(V) in contaminated water were reduced from initial concentration of 1.335 mmol/L to 0.054 mmol/L and 0.300 mmol/L by CaAl-monosulfate and CaAl-ettringite respectively. The post experimental results of PXRD and FESEM analysis indicate that arsenate removal was by ion exchange.