• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.113-116
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• 2006

Some nano hair systems in the nature are found to show excellent adhesive characteristic, which is called dry adhesive, and synthetic nano hairs to mimic these adhesiveness are believed to have many applications. To develop a practical synthetic dry adhesive system, we mold nano hairs on plastic substrates using thermoplstic materials including COC, PP, PC and PMMA. and estimate the moldability and the adhesive characteristic. As a template for molding nano hairs, AAO membrane is first adopted, which is 60um thick and 13mm in diameter. This membrane has about a billion of through-holes of which diameter is around 200nm. This AAO membrane and the pellet of materials are stacked in the mold and pressed to mold after heating up to be melted. The AAO membrane is removed using KOH to obtain the molded nano hairs. As a result, the diameter of the molded hairs is around 200nm and the length is $2um{\sim}60um$ depending on the molding conditions and materials. The molded nano hair substrates is estimated to show much better adhesive characteristic than a substrate without nano hairs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.04a
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• pp.123-126
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• 2003

Recently, there is a growing concern on the photovoltaic effects using organic materials. This is a phenomena which converts the solar energy into the electrical one. We have fabricated a device structure of $ITO/PEDOT:PSS/CuPc/C_{60}/BCP/AI$. The PEDOT:PSS layer is made by spin coating, and the other organic layers are made by thermal vapor deposition. By measuring the current-voltage characteristics with an illumination of light, we have obtained value of Voc=0.38V, Jsc=$0.5mA/cm^{2}$. And a fill factor and efficiency are about 0.314 and 0.083%, respectively. A 500W xenon lamp(ORIEL) is used for a light source, and the light intensity illuminated into the device was about 10mW.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.71.1-71.1
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• 2019

We report the first high-resolution (sub-arcminute) large-scale mapping $^{12}CO$ and $^{13}CO$ observations of the molecular clouds associated with the giant outer Galaxy H II region CTB 102 (KR 1). These observations were made using a newly commissioned receiver on the 13.7-m radio telescope at the Taeduk Radio astronomy Observatory (TRAO). Our observations show that the molecular clouds have a spatial extent of $60{\times}35pc$ and a total mass of $10^{4.8}-10^{5.0}$ solar mass, Infrared data from WISE and 2MASS were used to identify and classify the YSO population associated with ongoing star formation activity within the molecular clouds. Moving away from the H II region, there is an age/class gradient consistent with sequential star formation. The infrared and molecular line data were combined to estimate the star formation efficiency (SFE) of the entire cloud as well as the SFE for various sub regions of the cloud.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.235-235
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• 2017

Chromium (Cr) toxicity is hazardous to the seed germination, growth, and development of plants. ${\gamma}$-Aminobutyric acid (GABA) is a non-protein amino acid and is involved in stress tolerance in plants. To investigate the effects of GABA in alleviating Cr toxicity, we treated eight-d-old mustard (Brassica juncea L.) seedlings with Cr (0.15 mM and 0.3 mM $K_2CrO_4$, 5 days) alone and in combination with GABA ($125{\mu}M$) in a semi-hydroponic medium. The roots and shoots of the seedlings accumulated Cr in a dose-dependent manner, which led to an increase in oxidative damage [lipid peroxidation; hydrogen peroxide ($H_2O_2$) content; superoxide ($O{_2}^{{\cdot}-}$) generation; lipoxygenase (LOX) activity], MG content, and disrupted antioxidant defense and glyoxalase systems. Chromium stress also reduced growth, leaf relative water content (RWC), and chlorophyll (chl) content but increased phytochelatin (PC) and proline (Pro) content. Furthermore, supplementing the Cr-treated seedlings with GABA reduced Cr uptake and upregulated the non-enzymatic antioxidants (ascorbate, AsA; glutathione, GSH) and the activities of the enzymatic antioxidants including ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione peroxidase (GPX), superoxide dismutase (SOD), catalase (CAT), glyoxalase I (Gly I), and glyoxalase II (Gly II), and finally reduced oxidative damage. Adding GABA also increased leaf RWC and chl content, decreased Pro and PC content, and restored plant growth. These findings shed light on the effect of GABA in improving the physiological mechanisms of mustard seedlings in response to Cr stress.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3307-3311
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• 2013

A new fiber optical sensor was developed for the determination of 2,4-dichlorophenol (DCP). The sensor was based on DCP oxidation by oxygen with the catalysis of iron(III) tetrasulfophthalocyanine (Fe(III)PcTs). The optical oxygen sensing film with $Ru(bpy)_3Cl_2$ as the fluorescence indicator was used to determine the consumption of oxygen in solution. A lock-in amplifier was used for detecting the lifetime of the oxygen sensing film by measuring the phase delay change of the sensor head. The different variables affecting the sensor performance were evaluated and optimized. Under the optimal conditions (i.e. pH 6.0, $25^{\circ}C$, Fe(III)PcTs concentration of 0.62 mg/mL), the linear detection range and response time of the sensor are $1.0{\times}10^{-6}-9.0{\times}10^{-6}$ mol/L and 250 s, respectively. The sensor displays high selectivity, good repeatability and stability, and can be used as an effective tool in analyzing DCP concentration in practical samples.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3257-3260
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• 2013

Two new diphenylethylenes, gramniphenols H and I (1 and 2), together with six known diphenylethylenes (3-8), were isolated from Arundina graminifolia. The structures of 1-8 were elucidated by spectroscopic methods including extensive 1D- and 2D-NMR techniques. Compounds 1 and 2 were evaluated for their cytotoxicity against five human tumor cell lines. Compound 1 showed cytotoxicity against PC3 cells with $IC_{50}$ value of 3.5 ${\mu}M$. Compound 2 showed cytotoxicity against NB4 and PC3 cells with $IC_{50}$ values of 3.6 and 3.8 ${\mu}M$, respectively.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.133-137
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• 2015

The Galactic center uniquely provides opportunities to resolve how star clusters form in neutral gas overdensities engulfed in a large-scale accretion flow. We have performed sensitive Green Bank 100m Telescope (GBT), Karl G. Jansky Very Large Array (JVLA), and Submillimeter Array (SMA) mapping observations of molecular gas and thermal dust emission surrounding the Galaxy's supermassive black hole (SMBH) Sgr $A^{\ast}$. We resolved several molecular gas streams orbiting the center on ${\gtrsim}10$ pc scales. Some of these gas streams appear connected to the well-known 2-4 pc scale molecular circumnuclear disk (CND). The CND may be the tidally trapped inner part of the large-scale accretion flow, which incorporates inflow via exterior gas filaments/arms, and ultimately feeds gas toward Sgr $A^{\ast}$. Our high resolution GBT+JVLA $NH_3$ images and SMA+JCMT 0.86 mm dust continuum image consistently reveal abundant dense molecular clumps in this region. These gas clumps are characterized by ${\gtrsim}100$ times higher virial masses than the derived molecular gas masses based on 0.86 mm dust continuum emission. In addition, Class I $CH_3OH$ masers and some $H_2O$ masers are observed to be well associated with the dense clumps. We propose that the resolved gas clumps may be pressurized gas reservoirs for feeding the formation of 1-10 solar-mass stars. These sources may be the most promising candidates for ALMA to probe the process of high-mass star-formation in the Galactic center.

• Journal of the Korean earth science society
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• v.43 no.3
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• pp.351-366
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• 2022

We investigated the kinematic activity of the Type II Seyfert galaxy Mrk 1 based on H𝛽 and [O III] 5007 extracted from the MR 1 grism spectra observed with the OASIS attached to the CFHT 3.6 m telescope. The [O III] forbidden Gaussian line profiles exhibited asymmetric features with an excess of the blue component: (1) strongest at a distance of about 960 pc from the galaxy center, and (2) a wider line width of about ~900 km s^-1 in the NS direction of the center. The velocity distributions in the spectral images showed blue or approaching flow motion in the NE zone, while receding in the SW zone, implying the counter-clockwise rotation. The radial velocity data showed that the center of the AGN region appears to be blocked by gas-dust approaching toward the Earth.

• Korean Journal of Food Science and Technology
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• v.36 no.3
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• pp.385-392
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• 2004

Physicochemical and sensory characteristics of commercial Oiji, Korean pickled cucumbers (six commercial and three traditionally made products) were investigated. Saltiness values for commercial and traditionally made products were 3.424-4.47 and 3.92-7,23%, and acidity and pH were 3.43-3.85 and 0.39-0.75%, respectively, Commercial products showed lower L and higher b values than traditionally made products. Redness of both products ranged from -1.47 to -3.71. Numbers of total microbial, lactic acid bacteria, and yeast in traditionally made products ($1{\times}10^{7}-1.3{\times}10^{9},\;4{\times}10^{6}-4.7{\times}10^{8},\;and\;1.3{\times}10^{6}-3{\times}10^{8}\;cfu/mL,\;respectively$), were higher than those of commercial products ($1{\times}10^{4}-2{\times}10^{7},\;1{\times}10^{4}-6{\times}10^{6},\;and\;1{\times}10^{4}-6{\times}10^{6}cfu/mL\;respectively$). Texture analysis revealed fracturability (2,103-3,010 g) and hardness (409-890 g) varied among the products above. Overall acceptability scores of commercial products C1 and C2 were highest at 7.6-8.0 compared to other products (p<0.05). From the principal component analysis, the first principal component (PC1, 79.94%) and the second principal component (PC2, 19.94%) could describe the majority of the variability. Commercial product C1, C2, C3, and C7 having high negative loadings on the PC2 axis are closely related to over-all acceptability, over-all taste, savory taste and hardness. From Pearson correlation analysis, hardness and chewiness correlated positively with saltiness, whereas over-all acceptability, positively correlated with savory and overall taste, respectively (p<0.05).

• The Korean Journal of Pharmacology
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• v.31 no.1 s.57
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• pp.103-114
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• 1995

Platinum coordination complexes are currently one of the most compounds used in the treatment of solid tumors. However, its use is limited by severe side effects such as renal toxicity. Our platinum-based drug discovery program is aimed at developing drugs capable of diminishing toxicity and improving antitumor activity. We synthesized new Pt (Ⅱ) complex analogue containing 1,2-diaminocyclohexane (dach) as carrier ligand and 1,2-bis(diphenylphosphino) ethane (DPPE) as a leaving group. Furthermore, nitrate was added to improve the solubility. A new series of [Pt(trans-ddach)(DPPE).$2NO_3(PC)$ was synthesized and characterized by their elemental analysis and by various spectroscopic techniques [infrared (IR), $^{13}carbon$ nuclear magnetic resonance (NMR)]. PC demonstrated acceptable antitumor activity aganist P388, L-1210 lymphocytic leukemia cells and SK=OV3 human ovarian adenocarcinoma cells, and significant. activity as compared with that. cisplatin. The toxicity of PC was found quite less than thar of cisplatin using MTT, $[^3H]$ thymidine uptake and glucose consumption tests in rabbit proximal tubule cells, human kidney cortical cells and human renal cortical tissues. Based on these results, this novel platinum compound represent a valuable lead in the development of a new anticancer chemotherapeutic agent capable of improving antitumor activity and low toxicity.