• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.192-192
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• 2011

Hyperthermal ion scattering experiments were conducted with low kinetic energy (<35 eV) cesium ion beams to analyze the UV-photolyzed water-ice films. Neutral molecules (X) on the surface were detected as cesium-molecule ion clusters ($CsX^+$) which were formed through a Reactive Ion Scattering (RIS) process. Ionic species on the surface were desorbed from the surface via a low energy sputtering (LES) process, and were analyzed [1]. Using these methods, the thermal stability of hydronium ion ($H_3O^+$) that was produced by UV light was examined. As the thermal stability of $H_3O^+$ is related with the reaction, $H_3O^+$ + OH + $e^-$ (or $OH^-$) ${\rightarrow}$ $2H_2O$, which is similar or same with the reverse reaction of the auto-ionization of water, the result from this work would be helpful to understand the auto-ionization of $H_2O$ in water-ice that has not been well-understood yet. However, as $H_3O^+$ was not detected through a LES method, the titration experiment of $H_3O^+$ with methylamine ($CH_3NH_2$, MA), MA + $H_3O^+\;{\rightarrow}\;MAH^+$ + $H_2O$, was conducted. In this case, the presence of $MAH^+$ indicates that of $H_3O^+$ in the ice. Thus the pristine ice was photolyzed with UV light for a few minutes and this photolyzed ice was remained at the certain temperature for minutes without UV light. Then MA was adsorbed on that surface so that the population of $H_3O^+$ was found. From the calibration experiments, the relation of $MAH^+$ and $H_3O^+$ was found, so that the thermal stability of $H_3O^+$ can be investigated [2].

• 분석과학
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• 제8권4호
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• pp.611-615
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• 1995

The design of appropriate chemically modified electrodes should allow development of new voltammetric measurement schemes with enhanced selectivity and sensitivity. Microorganism like algae has high ability to trap toxic and heavy metal ions and different affinities for metal ions. A copper(II) ion-selective carbon paste electrode was constructed by incorporating alga Anabaena into a conventional carbon paste mixture, and then the film of 10% Nafion was coated to avoid the swelling of the electrode surface. Copper ion could be deposited at the 25% algamodified electrode for 15 min without the applied potential while stirring the solution by only immersing the electrode in a buffer (pH 4.0) cot1taining copper(II). Temperature was controlled at $35^{\circ}C$. After preconcentration was carried out the electrode was transferred to a 0.1 M potassium chloride solution and was reduced at -0.6 volt at $25^{\circ}C$. The differential pulse anodic stripping voltammetry was employed. A well-defined oxidation peak could be obtained at -0.1 volt (vs SCE). In five deposition / measurement / regeneration cycles, the responses were reproducible and relative standard deviations were 3.3% for $8.0{\times}10^{-4}M$ copper(II). Calibration curve for copper was linear over the range from $2.0{\times}10^{-4}M$ to $1.0{\times}10^{-3}M$. The detection limit was $7.5{\times}10^{-5}M$. Studies of the effect of diverse ions showed that the coexisting metal ions had little or no effect for the determination of copper. But anions such as cyanide. oxalate and EDTA seriously interfered.

• Applied Biological Chemistry
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• 제18권1호
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• pp.52-55
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• 1975

1) 본실험조건(本實驗條件)에서 GLC에 의하여 AsA의 최저(最低)농도(濃度) 1mg%까지 정량가능(定量可能)하였다. 2) TMS 반응조건(反應條件)으로서 동결건조시료(凍結乾燥試料)에는 반드시 TMS 혼합시액중(混合試液中)에서 추출(抽出)과 TMS 화(化)를 동시(同時)에 시켜야만 98% 이상(以上)의 회수율(回收率)을 얻을 수 있다. 3) AsA 농도(濃度)가 1mg%이상(以上)인 시료(試料)에 대(對)하여 GLC에 의한 미량정량(微量定豊)을 확립(確立)하여 특(特)히 방해물질(妨害物質)이 많은 일반식품(一般食品)의 정량(定量)에 적용(適用)이 가능(可能)하도록 하였다. 4) 본실험(本實驗)에 사용(便用)한 일본전자(日本電子)의 750형(型)의 eletron meter의 성능(性能)보다 감도(感度)가 300배(倍)인 20K 형(型)을 사용(使用) 한다면 혈청중(血淸中) AsA의 정량(定量) 및 그 이하(以下)의 농도(濃度)인 미량정량(微量定量)도 충분(充分)히 가능(可能)하리라 생각된다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.241-246
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• 2005

Doam watershed is located at alpine areas in the Kangwon province. The annual average precipitation, including snow accumulation during the winter, at the Doam watershed is significantly higher than other areas. Thus, pollutant laden runoff and sediment discharge from the alpine agricultural fields are causing water quality degradation at the Doam watershed. To estimate soil erosion from the agricultural fields, the Universal Soil Loss Equation (USLE) has been widely used because of its simplicity to use. The USLE rainfall erosivity (R) factor is responsible for impacts of rainfall on soil erosion. Thus, use of constant R factor for the Doam watershed cannot reflect variations in precipitation patterns, consequently soil erosion estimation. In the early spring at the Doam watershed, the stream flow increases because of snow melt, which results in erosion of loosened soil experiencing freezing and thaw during the winter. However, the USLE model cannot consider the impacts on soil erosion of freezing and thaw of the soil. Also, it cannot simulate temporal changes in USLE input parameters. Thus, the Soil and Water Assessment Tool (SWAT) model was investigated for its applicability to estimate soil erosion at the Doam watershed, instead of the widely used USLE model. The SWAT hydrology and erosion/sediment components were validated after calibration of the hydrologic component. The $R^2$ and Nash-Sutcliffe coefficient values are higher enough, thus it was found the SWAT model can be efficiently used to simulate hydrology and sediment yield at the Doam watershed. The effects of snow melt on SWAT estimated stream flow and sediment were investigated using long-term precipitation and temperature data at the Doam watershed. It was found significant amount of flow and sediment in the spring are contributed by melting snow accumulated during the winter. Thus, it is recommend that the SWAT model capable of simulating snow melt and long-term weather data needs to be used in estimating soil erosion at alpine agricultural land instead of the USLE model for successful soil erosion management at the Doam watershed.

• 한국환경농학회지
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• 제31권2호
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• pp.113-121
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• 2012

BACKGROUND: The Doam watershed in Korea has been managed for the reduction and the prevention of non-point source pollution since 2007. Especially, the water quality of the Doam reservoir is a primary issue related to the Doam dam reoperation. We have carried out the modeling to evaluate the water quality based on suspended solids (SS) of the Doam watershed and the Doam reservoir. Two powerful hydrological and water quality models (HSPF and CE-QUAL-W2) were employed to simulate the combined processes of water quantity and quality both in the upland watershed of the Doam reservoir and the downstream waterbody. METHODS AND RESULTS: The HSPF model was calibrated and validated for streamflow and SS. The CE-QUAL-W2 was calibrated for water level, water temperature, and SS and was validated for the only water level owing to data lack. With the parameters obtained through the appropriate calibration, SS concentrations of inflow into and in the Doam reservoir were simulated for three years (2008, 2004 and 1998) of the minimum, the average, and the maximum of total annual precipitation during recent 30 years. The annual average SS concentrations of the inflow for 2008, 2004, and 1998 were 8.6, 10.9, and 18.4 mg/L, respectively and those in the Doam reservoir were 9.2, 13.8, and 21.5 mg/L. CONCLOUSION(s): The results showed that more intense and frequent precipitation would cause higher SS concentration and longer SS's retention in the reservoir. The HSPF and the CE-QUAL-W2 models could represent reasonably the SS from the Doam watershed and in the Doam reservoir.

• 약학회지
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• 제60권2호
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• pp.64-72
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• 2016

Jakyakgamcho-tang is a well-known traditional herbal medicine and has been used for the treatment of mainly pains in oriental medicine. In this study, analytical method for the quantitative determination of the eleven marker components, gallic acid (1), oxypaeoniflorin (2), paeoniflorin (3), albiflorin (4), liquiritin (5), isoliquiritin (6), ononin (7), liquiritigenin (8), benzoylpaeoniflorin (9), paeonol (10), and glycyrrhizin (11) in Jakyakgamcho-tang decoction was performed using an ultra-performance liquid chromatography-electrospray ionization-mass spectrometer. The analytical column for separation of the compounds 1~11 was used an UPLC BEH $C_{18}$ ($100{\times}2.1mm$, $1.7{\mu}m$) column and column oven temperature was maintained at $45^{\circ}C$. The mobile phase consisted of 0.1% (v/v) aqueous formic acid (A) and acetonitrile (B) by gradient elution. The flow rate was 0.3 ml/min and injection volume was $2.0{\mu}l$. Correlation coefficient in the calibration curves of the compounds 1~11 were showed a good linearity with more than 0.99. The limit of detection and limit of quantification values of the compounds 1~13 were detected in the ranges 0.06~18.43 ng/ml and 0.18~58.29 ng/ml, respectively. Among the compounds 1~11, the compounds 10 were not detected in this sample, while the ten compounds, 1~9 and 11, were detected $44.05{\sim}19,289.05{\mu}g/g$ in Jakyakgamcho-tang extract.

• 약학회지
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• 제54권3호
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• pp.157-163
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• 2010

A high-performance liquid chromatography (HPLC) with DAD detector and electrospray ionization mass spectrometry (ESI-MS) was established for the simultaneous determination of coniferin (1), loganic acid (2), demethylsecologanol (3), sweroside (4) and loganin (5) from caulis Lonicera joponica. The optimal chromatographic conditions were obtained on an ODS column ($5{\mu}m$, $4.6{\times}150mm$) with the column temperature $35^{\circ}C$. The mobile phase was composed of (A) water with 0.1% formic acid and (B) methanol with 0.1% formic acid using a gradient elution, the flow rate was 0.3 ml/min. Detection wavelength was set at 254 nm. All calibration curves showed good linear regression ($r^2$>0.998) within test ranges. The developed method provided satisfactory precision and accuracy with overall intra-day and interday variations of 0.16~3.28% and 0.14~1.99%, respectively, and the overall recoveries of 99.39~105.89% for the five compounds analyzed. The verified method was successfully applied to quantitative determination of the two types (phenolic compounds and iridoids) of bioactive compounds in 24 commercial caulis L. japonica samples from different markets in Korea and China. The analytical results demonstrated that the contents of the five analytes vary significantly with sources.

• 약학회지
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• 제55권1호
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• pp.64-68
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• 2011

In this study, a high performance liquid chromatography-diode array detector method was established, for simultaneous determination of three compounds, berberine, palmatine and geniposide in Hwangryunhaedok-tang, To develop and validate method, $C_{18}$ column (5 ${\mu}M$, 4.6 mm${\times}$250 mm) was used with gradient mobile phase, water containing 0.1% trifluoroacetic acid (TFA) and MeOH at the column temperature of $30^{\circ}C$. UV wavelength was set at 230 and 280 nm. Validation of the chromatography method was evaluated by linearity, precision and accuracy test. Calibration curve of standard components showed good linearity ($R^2$ > 0.9999). The limits of detection (LOD) and limits of quantification (LOQ) varied from 0.05 to 0.17 ${\mu}g/ml$ and 0.15 to 0.53 ${\mu}g/ml$, respectively. The relative standard deviations (RSDs) data of intra-day and inter-day test were in less than 2.99% and 1.90%, respectively. The results of the accuracy test were in the range of 98.36 to 102.52% with RSDs values 0.32 to 1.98%. The results of validation indicated that this method was a very accurate and sensitive assay.

• 대한화학회지
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• 제45권3호
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• pp.223-229
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• 2001

흐름주입 장치를 이용하여 화학발광법에 의한 전혈 중의 당을 정량하는 방법에 대하여 연구하였다. 당의 효소반응에서 생성되는 과산화수소에 의하여 424nm에서 발생하는 luminol의 화학발광 세기의 차이를 정량에 이용하였다. 효소반응기는 glucose oxidase를 aminopropyl glass bead에 혼입하여 만들었으며, 흐름셀에서 발생하는 화학발광의 세기는 광섬유 다발을 이용하여 측정하였다. 최적 실험조건을 구하기 위하여 화학발광 시약 및 효소반응기의 pH, 흐름속도 및 온도가 화학발광세기에 미치는 영향을 조사하였다. 최적실험조건에서 구한 검정 곡선은 $1.0{\times}10^{-1}$~ 7.0mM에서 직선성이 성립하였으며, 검출한계는 $6.0{\times}10^{-2}$mM이었다. 본 방법을 전혈 중의 당 정량에 적용하였으며, 그 결과를 기존의 분석법에서 구한 결과와 비교하였다. 또한, 회수율 측정을 통하여 본 방법의 신뢰성을 검증하였다.

• 한국자기학회지
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• 제11권1호
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• pp.38-44
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• 2001

저자장 영역(1 mT 이하)에서 국가 표준시스템을 분해능 0.26 nT 수준으로 확립하였다. 비자성 재료로 건축하여 자성체에 의한 영향을 배제할 수 있는 비자성동에서 세슘 광펌핑 마그네토미터, 3-축 헬름홀츠 코일 등을 이용하여 자동적으로 지자장을 상쇄시키는 장치를 만들었다. 그 특성은 대역폭 10 Hz에서 0.1 nT/10 min이었다. 지자장이 상쇄된 공간에 최적 설계한 단전류-다층 솔레노이드(길이 1.02 m, 평균반경 0.l1467 m, 단위길이당 권선수 1000 turns/m)를 설치하고, 솔레노이드에 정밀 전류를 홀려 자장을 발생시키는 방법을 사용하여 저자장 표준시스템의 성능을 향상시켰다. 솔레노이드 중심에서 자장의 안정도는 $\pm$ 1 cm 범위에서 1.0$\times$$10^{-7}$ T이었다. 핼륨 광펌핑 마그네토미터를 이용하여 측정한 솔레노이드의 코일상수는 1.231 058 9 mT/A이고, 온도계수는 0.38 nT/$^{\circ}C$이었다. 저자장 표준시스템은 저자장 측정기의 교정 및 저자장관련 시험검사 등에 사용된다.