• Bulletin of the Korean Chemical Society
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• v.16 no.7
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• pp.654-657
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• 1995

A series of excitation spectra (7Fo→5Do transition) of Eu(Ⅲ) ion in aqueous solution ([Eu(Ⅲ)]=1.12 × 10-2 mol L-1; pH 1.0 to 7.0) were obtained under CO2 free atmosphere using a pulsed tunable dye laser system. The broad and low intensity spectra (peak maximum: 578.89 nm) showed that the trivalent ion (Eu3+) underwent a low degree of hydrolysis at pH below 6.0. Eu(Ⅲ) hydroxo complex formation seemed more significant at pH above 6.0, shown by the occurrence of intense new peak at 578.63 nm. The spectra of those solutions prepared in N2 atmosphere showed no signs of the presence of interfering carbonate species. The Eu(Ⅲ) hydroxo complex formation was not observed when complexation studies between Eu(Ⅲ) ion and weak organic acids (e.g. glutarate and diglycolate) were conducted at pH 6.0 or below.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.651-654
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• 2009

Novel compounds with rod and disc mesogens were synthesized and characterized. The molecular structures were confirmed by FT-IR, $^1H$-NMR spectroscopy and elemental analysis. The optical properties of these molecules were investigated by UV-vis absorption spectroscopy and photo-luminescence spectroscopy. We found that they are a novel series of blue light-emitting molecules. The absorption spectra peaks of these compounds varied from 336 nm-341 nm, while the maximum emissions centered form 410 nm-450 nm in chloroform solution. However, unexpectedly we could not found their biaxiality and mesomorphic properties by POM, conoscopy and DSC method.

• Bulletin of the Korean Chemical Society
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• v.19 no.6
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• pp.654-660
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• 1998

$[Fe^{II}Fe^{III}BPLMP(OAc)_2](BPh_4)_2$ (1), a new model for the reduced form of the purple acid phosphatases, has been synthesized by using a dinucleating ligand, 2,6-bis[((2-pyridylmethyl)(6-methyl-2-pyridylmethyl)amino) methyl]-4-methylphenol (HBPLMP). Complex I has been characterized by X-ray diffraction method as having (μ-phenoxo)bis(acetato)diiron core. Complex 1 was crystallized in the monoclinic space group C2/c with the following cell parameters: a=41.620(6) Å, b=14.020(3) Å, c=27.007(4) Å, β=90.60(2)°, and Z=8. The iron centers in the complex 1 are ordered as indicated by the difference in the Fe-O bond lengths which match well with typical $Fe^{III}-O\; and\; Fe^{II}-O$ bond lengths. Complex 1 has been studied by electronic spectral, NMR, EPR, SQUID, and electochemical methods. Complex 1 exhibits strong bands at 592 nm, 1380 nm in $CH_3CN$ (ε = 1.0 × 103 , 3.0 × 102). These are assigned to $phenolate-to-Fe^{III}$ and intervalence charge-transfer transitions, respectively. Its NMR spectrum exhibits sharp isotropically shifted resonances, which number half of those expected for a valence-trapped species, indicating that electron transfer between $Fe^{II}\;and\;Fe^{III}$ centers is faster than NMR time scale. This complex undergoes quasireversible one-electron redox processes. The $Fe^{III}_2/Fe^{II}Fe^{III}\;and\;Fe^{II}Fe^{III}/Fe^{II}_2$ redox couples are at 0.655 and -0.085 V vs SCE, respectively. It has $K_{comp}=3.3{\times}10^{12}$ representing that BPLMP/bis(acetate) ligand combination stabilizes a mixed-valence $Fe^{II}Fe^{III}$ complex in the air. Complex 1 exhibits a broad EPR signal centered near g=1.55 which is a characteristic feature of the antiferromagnetically coupled high-spin $Fe^{II}Fe^{III}$ system $(S_{total}=1/2)$. This is consistent with the magnetic susceptibility study showing the weak antiferromagnetic coupling $(J= - 4.6\;cm^{-1},\; H= - 2JS_1{\cdot}S2)$ between $Fe^{II}\; and \;Fe^{III}$center.

• Horticultural Science & Technology
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• v.30 no.6
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• pp.664-672
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• 2012

As an artificial light source, light-emitting diode (LED) with a short wavelength range can be used in closed-type plant production systems. Among various wavelength ranges in visible light, individual light spectra induce distinguishing influences on plant growth and development. In this study, we determined the effects of monochromatic LEDs on leaf shape index, growth and the accumulation of phytochemicals in a red leaf lettuce (Lactuca sativa L. 'Sunmang') and a green leaf lettuce (Lactuca sativa L. 'Grand rapid TBR'). Lettuce seedlings grown under normal growing conditions ($20^{\circ}C$, fluorescent lamp + high pressure sodium lamp, $130{\pm}5{\mu}mmol{\cdot}m^{-2}{\cdot}s^{-1}$, 12 hours photoperiod) for 18 days were transferred into incubators at $20^{\circ}C$ equipped with various monochromatic LEDs (blue LED, 456 nm; green LED, 518 nm; red LED, 654 nm; white LED, 456 nm + 558 nm) under the same light intensity and photoperiod ($130{\pm}7{\mu}mmol{\cdot}m^{-2}{\cdot}s^{-1}$, 12 hours photoperiod). Leaf length, leaf width, leaf area, fresh and dry weights of shoots and roots, shoot/root ratio, SPAD value, total phenolic concentration, antioxidant capacity, and the expression of a key gene involved in the biosynthesis of phenolic compounds, phenylalanine ammonia-lyase (PAL), were measured at 9 and 23 days after transplanting. The leaf shape indexes of both lettuce cultivars subjected to blue or white LEDs were similar with those of control during whole growth stage. However, red and green LEDs induced significantly higher leaf shape index than the other treatments. The green LED had a negative impact on the lettuce growth. Most of growth characteristics such as fresh and dry weights of shoots and leaf area were the highest in both cultivars subjected to red LED treatment. In case of red leaf lettuce plants, shoot fresh weight under red LED was 3.8 times higher than that under green LED at 23 days after transplanting. In contrast, the accumulation of chlorophyll, phenolics including antioxidants in lettuce plants showed an opposite trend compared with growth. SPAD value, total phenolic concentration, and antioxidant capacity of lettuce grown under blue LED were significantly higher than those under other LED treatments. In addition, PAL gene was remarkably activated by blue LED at 9 days after transplanting. Thus, this study suggested that the light quality using LEDs is a crucial factor for morphology, growth, and phytochemicals of two lettuce cultivars.

• Journal of the Korean Chemical Society
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• v.63 no.6
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• pp.453-458
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• 2019

Synthesis of ZnCo₂O₃ oxide is performed by sol-gel method via nitrate-citrate route. Powder X-ray diffraction (XRD) study shows monoclinic unit cell having lattice parameters: a = 5.721(1) Å, b = 8.073(2) Å, c = 5.670(1) Å, β = 93.221(8)°, space group P_2/m and Z = 4. Average crystallite sizes determined by Scherrer equation are the range ~14-32 nm, whereas SEM micrographs show nano-micro meter size particles formed in ZnCo₂O₃. Endothermic peak at ~798 K in the Differential scanning calorimetric (DSC) trace without weight loss could be due to structural transformation and the endothermic peak ~1143 K with weight loss is due to reversible loss of O₂ in air atmosphere. Energy Dispersive X-ray (EDX) analysis profile shows the presence of elements Zn, Co and O which indicates the purity of the sample. Magnetic measurements in the range of +12 kOe to -12 kOe at 10 K, 77 K, 120 K and at 300 K by PPMS-II Physical Property Measurement System (PPMS) shows hysteresis loops having very low values of the coercivity and retentivity which indicates the weakly ferromagnetic nature of the oxide. Observed X-band EPR isotropic lineshapes at 300 K and 77 K show positive g-shift at g_iso ~2.230 and g_iso ~2.217, respectively which is in agreement with the presence of paramagnetic site Co²⁺(3d⁷) in the oxide. DC conductivity value of 2.875 ×10^-8 S/cm indicates very weakly semiconducting nature of ZnCo₂O₃ at 300 K. DRS absorption bands ~357 nm, ~572 nm, ~619 nm and ~654 nm are due to the d-d transitions ⁴T_1g(⁴F)→²E_g(²G), ⁴T_1g(⁴F)→⁴T_1g(⁴P), ⁴T_1g(⁴F)→⁴A_2g(⁴F), ⁴T_1g(⁴F)→⁴T_2g(⁴F), respectively in octahedral ligand field around Co²⁺ ions. Direct band gap energy, E_g~ 1.5 eV in the oxide is obtained by extrapolating the linear part of the Tauc plot to the energy axis indicates fairly strong semiconducting nature of ZnCo₂O₃.

• Food Science of Animal Resources
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• v.37 no.5
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• pp.654-662
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• 2017

Extracellular microvesicles are membranous nano-sized cellular organelles secreted by a variety of cells under normal and pathological conditions and heterogeneous in size ranging from 30 nm to $1{\mu}m$. They carry functional microRNAs that can influence immunity and development. For a particular application of microvesicles, choice of isolation method is particularly important; however, their isolation methods from colostrum in particular have not been described clearly. In this work, differential ultracentrifugation as a conventional method, ultracentrifugation with some modification such as additional precipitations, ultrafiltration, sucrose gradient separation and ExoQuick$^{TM}$ as a commercial reagent were compared. The goal was to compare mainly microvesicular total microRNA yield, distribution and purity among the methods then select the best isolation method for bovine colostrum microvesicles based largely on microRNA yield with the view of applying the vesicles in work where vesicular microRNA cargo is the target bioactive component. Highest yields for vesicular microRNA were obtained using conventional methods and among them, subsequent ultracentrifugation with 100,000 g and 135,000 g conventional method 2 was selected as it had the highest RNA to protein ratio indicating that it pelleted the least protein in relation to RNA an important factor for in vivo applications to assess microvesicle functionalities without risk of contaminating non-vesicular biomaterial. Microvesicles isolated using conventional method 2 were successfully internalized by cells in vitro showing their potential to deliver their cargo into cells in vitro and in vivo in case of functional studies.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.4
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• pp.654-658
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• 1996

Organic acid content and volatile aroma components in Jehotang were investigated. Organic acids were detceted by HPLC and it is composed of formic acid(0.07%). lactic acid(0.22%) acetic acid (0.32%), and citric acid(3.17%), the last of which is one of the noteworthy features of Jehotang contributing greatly to its sour flavor and taste. Among the 39 volatile aroma components, whose peaks were identified by GC/MSD, and whose structures were analyzable, 17 kinds of hydrocarbon(30.81%) one kind of aldehyde(7.18%), 2 kinds of ketone(4.79%), 8 kinds of terpene(25.96%) a variety of acids (16%), 2 kinds of alcohol(5.42%), 2 kinds of phenol(2.76%) and 3 kinds of the others(7.68%) were found. The hydrocarbons, terpenes and acids occupied 70% of the aroma components, contributing to and also composing the particular flavor of Jehotang. Extracted pigments from the Jehotang showed maximum light absorbance in the wave length ranges of 200~400nm, showing a high degree of light adsorption of yellow to red color.

• Korean Journal of Materials Research
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• v.7 no.8
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• pp.654-659
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• 1997

HMDS[Si$_{2}$(CH$_{3}$)$_{6}$]단일 선구체를 이용하여 화학증착 방법으로 성장된 3C-SiC/Si(001) 이종접합박막의 특성을 XRD, 라만 스펙트럼 및 투과전자현미경(TEM)등을 이용하여 조사하였으며 시판되고 있는 상용 3C-SiC/Si 시편을 같은 방법으로 분석하여 특성을 비교검토하였다. $C_{3}$H$_{8}$-SiH$_{4}$-H$_{2}$혼합가스를 선구체로 이용하여 5$\mu\textrm{m}$두께로 성장된 상용 3C-SiC/Si 이종접합박막 시료의 XRD스펙트럼에서는 강한 3C-SiC(002)피크 만이 관찰되었으며, 라만 스펙트럼의 LO피크는 970nm$^{-1}$ 정도에서 강하게 나타났다. TEM 관찰 결과 다수의 전위, 쌍정, 적층결함 및 APB와 같은 결정결함들이 3C-SiC/Si 계면 근처에 집중적으로 분포되어 있었으며 성장된 박막은 단결정임을 확인할 수 있었다. 선구체로 HMDS를 사용하여 0.3$\mu\textrm{m}$ 및 2$\mu\textrm{m}$ 두께로 성장시킨 3C-SiC/Si 박막 시료의 XRD 스펙트럼은 다소 완만한 3C-SiC(002) 피크와 함께 3C-SiC(111)피크가 관찰되었으며, TEM으로 확인한 결과 소경각 결정립들이 약 5˚-10˚ 정도 방위차를 가지고 성장하여 기둥구조(columnar structure)를 이루고 있기 때문임을 알 수 있었다. 라만 스펙트럼 분석 결과 박막의 LO 피크가 967-969nm$^{-1}$정도로 다소 낮은 wavenumber쪽으로 이동되어 박막 내에 상당한 응력이 존재함을 확인할 수 있었다. 이와 같은 HMDS 3C-SiC박막의 특성은 성장 온도가 낮고 박막 성장용 가스로 사용한 HMDS 선구체에서 탄소가 과잉으로 공급되기 때문으로 제안되었다.다.

• Journal of the Korean Institute of Gas
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• v.28 no.1
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• pp.53-58
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• 2024

Due to the development of industry and improvement of living standards, the amount of natural gas used in the world is constantly increasing, and related industrial facilities such as power plants, storage facilities, and supply pipelines are constantly increasing. Natural gas is a convenient and clean fuel that does not pollute the environment, but in the event of an accident due to leakage, it can cause human casualties, large-scale property damage, and negative effects on the global warming effect. In addition to the severe penalties under the Severe Disaster Punishment Act, it is necessary to ensure safety. Therefore, by applying the principle of laser-based absorption spectroscopy, we developed a long-range portable methane leakage gas detection system that can detect the concentration of methane leaking from a distance of up to 30 meters and verified its effectiveness.

• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.649-654
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• 1994

In order to provide a quality index of Korean folk sojues, physicochemical properties of Korean folk sojues (Andong soju, Moonbaesul, Leekangju, Jindo Hongju, Chebiwon soju, Yethyang (rice) and Yethyang (barley)), Paekrosul, Chinese kaoliangchiews (Moutaichiew, Ergoutoutiu, Chuyehchingchiew, Zhikukaoliangchiew and Paigal), Japanese Senbatanuki shochu and two whiskies were determined. The pH of sojues ($3.43{\sim}5.85$) were mainly influenced by total acidity which was described as acetic acid. The conductivities of Paekrosul and Leekangju showed relatively high value of $246\;and\;122.7{\mu}S/cm$, respectively. Korean folk sojues and Paekrosul showed maximum absorption at 274 or $278{\sim}280nm$ in the spectrometric study. We performed principal components analysis (PCA) of physicochemical properties and spectrometric data to extract representative characteristics and to compare the similarity or the dissimilarity. The PCA plot showed the distinguished cluster of Korean folk sojues comparing with Chinese kaoliangchiew or Paekrosul etc.