• Bulletin of the Korean Chemical Society
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• v.30 no.7
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• pp.1470-1474
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• 2009

Thermal and photochemistry of methyl iodide ($CH_3I)\;adsorbed\;on\;D_2O$ ice film on Cu(111) at 100 K were studied using temperature-programmed desorption (TPD) time-of-flight mass spectrometry (TOF-MS), X-ray and ultraviolet photoelectron spectroscopies. On the basis of TPD, multilayer and monolayer $CH_3I$ molecules desorb from $D_2O$ ice layer at 120 and 130 K, respectively. Photo-irradiation at 100 K exhibits dramatic changes in the TPD and I $3d_{5/2}\;XPS\;of\;CH_3I$ on ice film, due to a dramatic dissociation of $CH_3I$. The dissociation is likely activated by solvated electrons transferred from the metal substrate during photo-irradiation. No other photo-initiated reaction products were found within our instrumental detection limit. During photo-irradiation, the $CH_3I$, $CH_3$ and I could be trapped (or solvated) in ice film by rearrangement (and self-diffusion) of water molecules. A newly appeared parent molecular desorption peak at 145 K is attributed to trapped $CH_3I$. In addition, the $CH_3$ and I may diffuse through ice and chemisorb on Cu(111), indicated by TPD and I $d_{5/2}$ XPS taken with photo-irradiation time, respectively. No molecular ejection was found during photo-irradiation at 100 K. The work functions for $CH_3I/Cu(111),\;D_2O/Cu(111)\;and\;CH_3I/D_2$O/Cu(111) were all measured to be about 3.9 eV, 1.0 eV downward shift from that of clean Cu(111).

• Korean Journal of Plant Resources
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• v.15 no.2
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• pp.89-95
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• 2002

In woody plant germplasms, using prefrozen dormant buds for materials is one way to achieve successful cryopreservation. The protocol of cryopreservation for White birch (Betula platyphylla var. japonica) winter vegetative buds is the following. First, the branches of White birch were collected in January 20, when the vegetative buds were still in a state of quiescence. The winter buds with about 5㎜ of xylem tissue were removed from the branches. They were dehydrated to moisture contents about 44% by air dry treatment. The buds were prefrozen, with the temperature being decreased by 5∼-20$\^{C}$ and then transfered to the LN(liquid nitrogen) maintained below -l96$\^{C}$. After cryopreservation, the vegetative buds were rapidly thawed in a water bath at 40$\pm$5$\^{C}$. In this case, the cell survival rate of samples was about 86%. After sterilization, buds were then cultured on MS medium. These results demonstrate the feasibility for cryopreservation of winter vegetation buds of Betula platyphylla var. japonica.

• Bulletin of the Korean Chemical Society
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• v.34 no.5
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• pp.1421-1424
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• 2013

Two new isoflavanones, (3R) 5,7,3',4'-tetrahydroxy-2'-methoxyisoflavanone (1) and (3R) 5',8-di-(${\gamma}$,${\gamma}$-dimethylallyl)-2',5-dihydroxyl-4',7-dimethoxyl-isoflavanone (2), were isolated from Uraria clarkei, together with two known compounds dalbergioidin (3), 5,7-dihydroxy-2',4'-dimethoxyisoflavanone (4). The structures involving the absolute configuration of the new compounds were well elucidated by MS, IR, UV, CD, 1D and 2D NMR analyses. Cytotoxicity of the four compounds were assessed, results suggested that compound 2 possessed well cytotoxic activity, against the Hela, K562, and HL60 cell lines with $IC_{50}$ values of 28.0, 40.6 and $35.1{\mu}M$, respectively.

• Archives of Pharmacal Research
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• v.29 no.11
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• pp.998-1005
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• 2006

The effects of imipramine on A-type delayed rectifier $K^{+}$ currents and ATP-sensitive $K^{+}\;(K_{ATP)$ currents were studied in isolated murine proximal colonic myocytes using the whole-cell patch-clamp technique. Depolarizing test pulses between-80 mV and +30 mV with 10 mV increments from the holding potential of-80 mV activated voltage-dependent outward $K^{+}$ currents that peaked within 50 ms followed by slow decreasing sustained currents. Early peak currents were inhibited by the application of 4-aminopyridine, whereas sustained currents were inhibited by the application of TEA. The peak amplitude of A-type delayed rectifier $K^{+}$ currents was reduced by external application of imipramine. The half-inactivation potential and the half-recovery time of A-type delayed rectifier $K^{+}$ currents were not changed by imipramine. With 0.1 mM ATP and 140 mM $K^{+}$ in the pipette and 90 mM $K^{+}$ in the bath solution and a holding potential of -80 mV, pinacidil activated inward currents; this effect was blocked by glibenclamide. Imipramine also inhibited $K_{ATP}$ currents. The inhibitory effects of imipramine in A-type delayed rectifier $K^{+}$ currents and $K_{ATP}$ currents were not changed by guanosine 5-O-(2-thiodiphosphate) ($GDP{\beta}S$) and chelerythrine, a protein kinase C inhibitor. These results suggest that imipramine inhibits A-type delayed rectifier $K^{+}$ currents and $K_{ATP}$ currents in a manner independent of G-protein and protein kinase C.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1656-1658
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• 2003

고전압 대전류 시스템에 사용하는 스위치의 기본 요구조건은 저가, 긴 수명, 적은 지터와 대용량 그리고 seal-off 형태로 쉽게 설치하여 운전하는 것이다. 본 논문은 고전압 대전류용 Seal-off TVS (Triggered Vacuum Switch)를 개발하는 것을 목적으로 하고있다. 제작한 TVS는 양전극과 음전극이 교대로 고정된 간격으로 각각 3개의 전극으로 배열되어 있으며 전극은 사다리꼴 모양으로 되어있고 트리거 시스템과 개스를 흡수하는 게터가 내부에 설치되어 있다. 제작한 스위치 내부는 약 $10^{-7}$ torr의 진공상태를 유지하고 있으며 세라믹 챔버를 사용하여 Seal-off 상태로 설계, 제작하였다. TVS의 에너지 최고 전달량은 74 C 이며 30 kV, 100 kA, $1{\sim}2$ ms의 스위치를 제작하여 시험을 하였다. 스위치 시험 장치는 200 ${\mu}F$, 22 kV 6개를 병렬로 연결한 커패시터 뱅크와 160 ${\mu}H$의 인덕터와 0.2 ${\Omega}$의 저항을 이용하여 시험 장치를 구성하였다. 본 논문은 제작한 스위치의 전기적인 특성 시험한 결과에 대하여 논하고자 한다.

• Journal of Biosystems Engineering
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• v.30 no.5 s.112
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• pp.274-279
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• 2005

Impact is one of the major cause of damage to fruits druing varios processes from the production on the farm to the consumer. The tissue of fruits are ruptured in a very short period time less than 10ms by impact loading. Mechanical behavior of fruits under impact loading can be analyzed better with high speed sampling data acquisition system and one of them is a digital storage oscilloscope. A impact test system was developed to test the physical properties of fruits including apple, pear, and peach which may lead to a better understanding of the physical laws. The test system consisted of a digital storage oscilloscope and simple mechanism which can apply impact force to fresh produce. Rupture force, energy, and deffrmation were measured at the five levels of drop heights from 4 to 24cm fur each internal and external tissues. Rupture forces for apple and pear were in the range of 72.9 to 87.7 N and 70.8 to 84.1 N for external and internal tissues, respectively. Rupture forces far peach external tissues were in the range of 43.4 to 65.0 N.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.9
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• pp.94-102
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• 2008

Capacitor switching is essential for the economic operation and proper voltage control of KOREA electric utility distribution system. Voltage transients produced by capacitor switching (around 2.0 per unit at substation and 2.5 or less per unit at customer site, and lasting less then 1[ms]) do not have the magnitude or duration to interfere with the operation of computers, but they do disrupt the operation of adjustable speed drivers. The result of our research, ASD manufacturers should learn from the computer industry and design products that will operate satisfactory In the electrical envelopment in which they will be placed. In this case history, the inductors on the input to ADSs in order to prevent nuisance tripping from capacitor switching(and other causes within the apartment) proved to be an effective, low-cost solution.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.04a
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• pp.78-80
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• 2006

The hybrid thin-film (HTF) passivation layer composed of the Ultra Violet (UV) curable acrylate layer and MS-31 (MgO:$SiO_2$=3:1wt%) layer was adopted in organic light emitting device (OLEO) to protect organic light emitting materials from penetrations of oxygen and water vapors. The results showed that the HTF layer possessed a very low WVTR value of lower than $0.007gm/m^{2+}day$ at $37.8^{\circ}C$ and 100% RH. This value was within the limited range of the sensitivity of WVTR measurements. And the lifetime of the HTF passivated device became almost three times longer than that of the bare device. The HTF on the OLEO was found to be very effective in protect what from the penetrations of oxygen and moisture.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.1
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• pp.109-117
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• 2010

In the present study, the degradation characteristics of Lindane by Advanced Oxidation Processes(UV/$H_2O_2$, Photo-Fenton process) were studied. The degradation efficiency of Lindane in aqueous solution was investigated at various initial pH values, Fenton's reagent concentrations and initial concentrations of Lindane. GC-ECD was used to analyze lindane. Lindane has not been degraded without application of AOPs over two hours. But, approximately 5% of lindane was degraded with UV or $H_2O_2$ alone. Lindane with UV/$H_2O_2$ process showed approximately 7% higher removal efficiency than $H_2O_2$ process. In the UV/$H_2O_2$ process, the pH values did not affect the removal efficiency. The optimal mole ratio of $H_2O_2/Fe^{2+}$ for lindane degradation is about 1.0 in Photo-Fenton process. Also, the experimental results showed that lindane removal efficiency increased with the decrease of initial concentration of lindane. Under the same conditions, the order lindane of removal efficiency is as following : Photo-Fenton process > UV/$H_2O_2$ process > $H_2O_2$ process. In addition, intermediate products were identified by GC-MS techniques. Than PCCH(Pentachlorocyclohexene) was identified as a reaction intermediate of the Photo-Fenton process.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.721-727
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• 1998

An analytical method for simultaneous and rapid determination of organophosphorus, organochlorine, carbamate, and pyrethroid pesticides in polished rice was developed. The analysis is performed by gas chromatograph with mass selective detector (GC/MSD) in selected ion monitoring (SIM) mode. Pesticides were extracted from samples with acetone by automated Soxhlet apparatus and this extract was evaporated to dryness for the analysis. The residue was dissolved in hexane, followed by a treatment with a Sep-Pak florisil catridge. Pesticides were positively confirmed by GC/MS, retention times, and ion ratios. This analytical method allows a rapid, reliable, and a good recovery of hydrophilic pesticides. Except far captafol, captan, dichlofluanid and dichlorvos, recoveries of 42 pesticides were over 70%.