• Journal of The Korean Astronomical Society
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• v.41 no.5
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• pp.121-137
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• 2008

We present optical and near-infrared imaging and long-slit spectroscopy for the blue compact dwarf galaxy (BCD) Mrk 49 in the Virgo Cluster. The surface brightness distribution analysis shows that Mrk 49 consists of an off-centered blue bright compact core of r = 10" and a red faint outer exponential envelope. The $H_{\alpha}$ image and color difference suggest that these two components have different stellar populations: a high surface brightness population of massive young stars and an underlying low surface brightness population of older stars. The redder near-infrared colors of the inner most region suggest that the near-infrared flux of Mrk 49 originates from evolved massive stars associated with the current star-forming activity. The total apparent magnitude is $B_T\;=\;14.32$ mag and the mean effective surface brightness is ${\mu}_{eff}(B)\;=\;21.56$ mag $arcsec^{-2}$. Long-slit spectroscopy shows that Mrk 49 rotates apparently as a solid body within r = 10" in a plane at position angle 55 degrees with an amplitude of about $20\;km\;sec^{-1}$. The measured radial velocity of Mrk 49 was derived as $1,535\;km\;sec^{-1}$; and the total mass of stars and gases is in the range of 3 to $6\;{\times}\;10^9\;M_{\odot}$. The mass-to-light ratios for the central region of Mrk 49 in I and B band are estimated 1.0 and 0.5, respectively. The upper limit of the dark matter to visible matter ratio seems to be < 5. The oxygen abundance is $12\;+\;\log(O/H)\;=\;8.21\;{\pm}\; 0.1$ which is about one quarter of the solar value while the relative helium abundance appears to be similar to that of the sun.

• Journal of Powder Materials
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• v.27 no.3
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• pp.233-240
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• 2020

Nano-sized ZnSe particles are successfully synthesized in an aqueous solution at room temperature using sodium borohydride (NaBH₄) and thioglycolic acid (TGA) as the reducing agent and stabilizer, respectively. The effects of the mass ratio of the reducing agent to Se, stabilizer concentration, and stirring time on the synthesis of the ZnSe nanoparticles are evaluated. The light absorption/emission properties of the synthesized nanoparticles are characterized using ultraviolet-visible (UV-vis) spectroscopy, photoluminescence (PL) spectroscopy, and particle size analyzer (PSA) techniques. At least one mass ratio (NaBH4/Se) of the reducing agent should be added to produce ZnSe nanoparticles finer than 10 nm and to absorb UV-vis light shorter than the ZnSe bulk absorption wavelength of 460 nm. As the ratio of the reducing agent increases, the absorption wavelengths in the UV-vis curves are blue-shifted. Stirring in the atmosphere acts as a deterrent to the reduction reaction and formation of nanoparticles, but if not stirred in the atmosphere, the result is on par with synthesis in a nitrogen atmosphere. The stabilizer, TGA, has an impact on the Zn precursor synthesis. The fabricated nanoparticles exhibit excellent photo-absorption/discharge characteristics, suggesting that ZnSe nanoparticles can be alloyed without the need for organic solutions or high-temperature environments.

• Current Photovoltaic Research
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• v.2 no.3
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• pp.120-123
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• 2014

Thermal doping method using furnace is generally used for solar-cell wafer doping. It takes a lot of time and high cost and use toxic gas. Generally selective emitter doping using laser, but laser is very high equipment and induce the wafer's structure damage. In this study, we apply atmospheric pressure plasma for solar-cell wafer doping. We fabricated that the atmospheric pressure plasma jet injected Ar gas is inputted a low frequency (1 kHz ~ 100 kHz). We used shallow doping wafers existing PSG (Phosphorus Silicate Glass) on the shallow doping CZ P-type wafer (120 ohm/square). SIMS (Secondary Ion Mass Spectroscopy) are used for measuring wafer doping depth and concentration of phosphorus. We check that wafer's surface is not changed after plasma doping and atmospheric pressure doping width is broaden by increase of plasma treatment time and current.

• Journal of the Korean Chemical Society
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• v.59 no.2
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• pp.142-147
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• 2015

Two new chitosan derivatives, polyamine grafted chitosan copolymers have been synthesized for corrosion protection of carbon steel in acidic medium. First, methyl acrylate graft chitosan copolymer (CS-MAA) was prepared by the reaction of chitosan (CS) and methyl acrylate (MAA) via the Michael addition reaction. Then, CS-MAA was reacted with ethylene diamine (EN) and triethylene tetramine (TN) respectively to synthesize ethylene diamine grafted chitosan copolymer (CS-MAA-EN) and triethylene tetramine grafted chitosan copolymer (CS-MAA-TN), and the structures were characterized by Fourier-transform infrared spectroscopy (FT-IR). At last, the corrosion inhibition activities on Q235 carbon steel were investigated by using gravimetric measurements, metallographic microscope, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. The compounds CS-MAA-EN and CS-MAA-TN show an appreciable corrosion inhibition property against corrosion of Q235 carbon steel in 5% HCl solution at $25^{\circ}C$. It has been observed that CS-MAA-EN shows greater corrosion inhibition efficiency than CS-MAA-TN. The inhibition efficiency of CS-MAA-EN was close to 90% when the mass fraction concentration was 0.2%~0.3%; the inhibition efficiency of CS-MAA-TN was close to 85% when the mass fraction concentration was 0.02%. The present work provided very promising results in the preparation of green corrosion inhibitors.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.5
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• pp.653-656
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• 2009

This paper is intended as an investigation of the method of extraction and the analysis by high-performance liquid chromatography mass spectroscopy of decursin and decursinol angelate in the dried root of Angelica gigas Nakai. The extracted decursin and decursinol angelate were the purity of >95% using 60% ethanol at $-20^{\circ}C$ for 12 hours by HPLC analysis. Decursin and decursinol angelate were efficiently isolated using recycling HPLC. The purity of isolated decursin and decursinol angelate was identified as 99.97 and 99.40% by HPLC analysis, respectively. The molecular weights of Decursin and decursinol angelate were also identified as m/z=329 ($[M+H]^+$) and m/z=351 ($[M+Na]^+$) by mass spectroscopy.

• Journal of Applied Biological Chemistry
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• v.59 no.2
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• pp.103-106
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• 2016

The leaves of eggplant (Solanum melongena L.) were extracted with 80 % aqueous MeOH, and the concentrated extract was partitioned with n-hexane, EtOAc, n-BuOH, and water fractions. From the n-BuOH fraction, five compounds were isolated through the repeated silica gel, octadecyl silica gel, and Sephadex LH-20 column chromatographies. On the basis of physic-chemical and spectroscopic data including mass spectrometry, infrared spectroscopy, and nuclear magnetic resonance, they were identified to be caffeic acid (1), chlorogenic acid (2), cryptochlorogenic acid (3), panasenoside (4), and (6R,7E,9R)-4,7-megastigmadien-3-one-9-${\beta}$-${\small{D}}$-glucopyranoside (5). Compounds 3 and 4 were isolated for the first time from the leaves of S. melongena L. in this study.

• Korean Journal of Medicinal Crop Science
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• v.28 no.4
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• pp.245-253
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• 2020

Background: Research on hot water extracts of medicinal plants that are easily applicable in the clinical setting is essential. To confirm the anti-inflammatory-related active compounds present in the hot water extract of Eriobotrya japonica leaves, ability to inhibit nitric oxide (NO) production was measured and active compounds isolated from the extract were analyzed. Methods and Results: Sovent fractionation by solvent was performed to identify the active compounds present in the hot water extract, and the ability of the extract and the fractions obtained to inhibit NO production was measured. Subsequently, based on the results of liquid chromatography (LC) profile analysis of the n-butanol fraction that had a relatively high inhibitory ability of NO production, six subfractions were separated around the main peak. Among the separated subfractions spectra from mass spectroscopy (MS) were analyzed and standard comparisons were performed on the compounds of the three main peaks on the chromatogram. NO production inhibitory activity of subfraction 2 identified as neochlorogenic acid was the highest with an IC₅₀ of 18.49 ㎍/㎖ followed by that of subfraction 5 identified as cryptochlorogenic acid with IC₅₀ of 25.82 ㎍/㎖. Conclusions: Our result, it was confirmed that several caffeoylquinic acids, including neochlorogenic acid and cryptochlorogenic acid present in the hot water extract of E. japonica leaves have an important role as compounds exhibiting anti-inflammatory activity.

• Journal of Korean Society on Water Environment
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• v.38 no.1
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• pp.31-42
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• 2022

Dissolved organic matter (DOM), which changes according to various factors, is ubiquitously present from natural environments to engineered treatment systems. Only limited information is available regarding the environmental functions of DOM after bulk analyses are only applied for characterization. In this paper, latest DOM analytical techniques are briefly introduced, which include fluorescence excitation-emission matrix with parallel factor analysis (EEM-PARAFAC), size-exclusion chromatography with an organic carbon detector (SEC-OCD), carbon/nitrogen stable-isotope ratio, and Fourier transform-ion cyclotron resonance-mass spectroscopy (FT-ICR-MS). Recent examples of using advanced analyses to interpret the phenomena associated with DOM occurring in natural and engineered systems are presented here. Through EEM-PARAFAC, different components like protein-like, fulvic-like, and humic-like can be identified and tracked individually through the investigated systems. SEC-OCD allows researchers to quantify different size fractions. FT-ICR-MS provides thousands of molecular formulas present in bulk DOM samples. Lastly, carbon/nitrogen stable-isotope ratio offers reasonable tools for tracking the sources in environments. We also discuss the advantages and weakness of the above-mentioned characterizing tools. Specifically, they focus on single environmental factors (different sourced-DOM and interaction of sediment-pore water) or simple changes after individual treatment processes. Through collaboration with the advanced techniques later, they help the researchers to better understand environmental behaviors in aquatic systems and serve as essential tools for addressing various pending problems associated with DOM.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.5
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• pp.224-230
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• 2001

The characteristics of $NO/N_2O$ annealed reoxidized nitrided oxide being studied as super thin gate oxide and gate dielectric layers of Non-Volatile Semiconductor Memory (NVSM) were investigated by Dynamic Secondary Ion Mass Spectrometry (D-SIMS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), and Auger Electron Spectroscopy (AES). The specimen was annealed by $NO/N_2O$ after initial oxide process and then rcoxidized for nitrogen redistribution in nitrided oxide. Out-diffusion of incorporated nitrogen during the wet oxidation in reoxidation process took place more strongly than that of the dry oxidation. It seems to indicate that hydrogen plays a role in breaking the Si N bonds. As reoxidation proceeds, incorporated nitrogen of $NO/N_2O$ annealed nitrided oxide is obsen-ed to diffuse toward the surface and substrate at the same time. ToF-SIMS results show that SiON species are detected at the initialoxide interface, and Si,NO species near the new $Si_2NO$ interface that formed after reoxidation. These SiON and $Si_2NO$ species most likely to relate to the origin of the state of memory charge traps in reoxidized nitrided oxide, because nitrogen dangling bonds of SiON and silicon dangling bonds of $Si_2NO$ are contained defects associated with memory effect.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.37.2-37.2
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• 2016

There exist scaling relations that link the mass of supermassive black holes with both the velocity dispersion and the mass of the central stellar cusp of their host galaxies. This implies that galaxies co-evolve with their central black holes, potentially through the feedback from actively accreting supermassive black holes (AGN). We use integral field spectroscopy data from the 8.2m Gemini-North telescope to investigate ionized gas outflows in luminous local (z<0.1) Type 2 AGN. Our sample of 6 galaxies was selected based on their [OIII] dust-corrected luminosity (>$10^{42}erg/s$) and signatures of outflows in the [OIII] line profile of their SDSS spectra. These are arguably the best candidates to explore AGN feedback in action since they are < 1% of a large local type 2 AGN SDSS sample selected based on their [OIII] kinematics. Expanding on previously reported results concerning the kinematic decomposition and size determination of these outflows, here we report their photoionization properties and energetics. We find strong evidence that connect the extreme kinematics of the ionized gas with AGN photoionization. The kinematic component related to the AGN-driven outflow is clearly separated from other kinematic components, such as gravitation- or stellar-driven motions, on the velocity and velocity dispersion diagram. Our spatially resolved kinematic analysis reveals that up to 90% of the mass and kinetic energy of the outflow is contained within the central kiloparcec of the galaxy. The total mass and kinetic energy of the outflow correlate well with the AGN bolometric luminosity, resulting in energy conversion efficiencies between 0.01% and 1%. Intriguingly, we detect ubiquitous signs of ongoing circumnuclear star formation. Their small size, the centrally contained mass and energy, and the universally detected circumnuclear star formation cast doubts on the potency of these AGN-driven outflows as agents of negative feedback.