• Nuclear Engineering and Technology
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• v.49 no.7
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• pp.1489-1494
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• 2017

The use of a room-temperature gamma spectrometer is an issue in environmental radiation monitoring. To monitor radionuclides released around a nuclear power plant, suitable instruments giving fast and reliable information are required. High-pressure xenon (HPXe) chambers have range of resolution and efficiency equivalent to those of other medium resolution detectors such as those using NaI(Tl), CdZnTe, and $LaBr_3:Ce$. An HPXe chamber could be a cost-effective alternative, assuming temperature stability and reliability. The CEA LIST actively studied and developed HPXe-based technology applied for environmental monitoring. Xenon purification and conditioning was performed. The design of a 4-L HPXe detector was performed to minimize the detector capacitance and the required power supply. Simulations were done with the MCNPX2.7 particle transport code to estimate the intrinsic efficiency of the HPXe detector. A behavioral study dealing with ballistic deficits and electronic noise will be utilized to provide perspective for further analysis.

• Mass Spectrometry Letters
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• v.8 no.1
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• pp.14-17
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• 2017

The effect of cationization agent concentration on glycan detection via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was investigated using $Na^+$ ions in the form of NaCl as the cationization agent. NaCl solution concentrations ranging from 1 mM to 1 M were investigated. Glycans from ovalbumin were mixed with the cationization agent solution and the 2,5-dihydroxybenzoic acid (2,5-DHB) matrix solution in a volume ratio of 1:1:1. The resulting mixture was loaded onto the MALDI plate. Two MALDI-TOF MS instruments (Voyager DE-STR MALDI-TOF MS and Tinkerbell RT MALDI-TOF MS) were used for detection of glycans. The best detection, in terms of the number of identified glycans, the peak intensity, and the signal-to-noise (S/N) ratio, was obtained with NaCl concentrations of 0.01-0.1 M for both MALDI-TOF MS instruments.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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• pp.23-28
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• 2002

As the interest on the air pollution is gradually rising up at home and abroad, automotive industries have been working on the exhaust emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative aftertreatment systems, and using clean fuels. Methanol, ethanol, LNG, LPG, H2, reformulated gasoline are generally recognized as the clean fuel. Since the low price policy of government on LPG has expanded its vehicle market recently, there is concern of the exhaust emission of LPG vehicle. In this paper, we studied the value of LPG fuel as a clean fuel by comparing the results of the exhaust emission from LPG and Gasoline fueled vehicles, and discussed its limitation of LPG vehicle with mixer type as a fuel supply system. FTIR was used to understand the difference of exhaust emission components of LPG and Gasoline fueled vehicles.

• Bulletin of the Korean Chemical Society
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• v.21 no.11
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• pp.1101-1105
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• 2000

A simultaneous determination method of BTEX (benzene, toluene, ethylbenzene, o,m.p-xylene) and TPH (kerosene, diesel, jet fuel and bunker C) in soil with gas chromatography/flame ionization detection (GC-FID) was described. The effects of extracti on method, extraction solvent, solvent volume and extraction time on the extraction performance were studied. A sonication method was simpler and more efficient than Soxhlet or shaking methods. Sonication with 10 mL of acetone/methylene chloride (1 : 1, v/v) for 10 min was found to be optimal extraction conditions for 20 g of soil. Peak shapes and quantification of BTEX and TPH were excellent, with linear calibration curves over a wide range of 1-500 mg/L for BTEX and 10-5000 mg/L for TPH. Good reproducibilities by sonication were obtained, with the RSD values below 10%. By using about 20 g of soil, detection limits were 0.8 mg/L for BTEX and 10 mg/L for TPH. The advantages of this procedure are the use of simple and common equipment, reduced volumes of organic solvents, rapid extraction periods of less than 20 min, and simultaneous analysis of volatile and semivolatile compounds.

• Analytical Science and Technology
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• v.11 no.2
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• pp.139-144
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• 1998

For the ambient monitoring of acrylamide, the adequate condition of sampling and analysis was checked. The adequate adsorbents and desorption solvents were tested. The combination of charcoal tube as a adsorbent and acetone as a desorption solvent showed 87% desorption efficiency. Flame ionization detector was used to detect acrylamide. The detection limit was 0.814 mg acrylamide in 1 L acetone. It is the equivalent concentration of 0.0203 mg acrylamide in $1m^3$ air if the volume of air collected was 40L. The permissible exposure level (PEL) of acrylamide in the workplace air recommended by Occupational Safety and Health Administration (OSHA, USA) is 0.3 mg acrylamide in $1m^3$ air. So, it is very simple and economic analytical method for acrylamide to be set in the industrial hygiene laboratories.

• Progress in Medical Physics
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• v.7 no.2
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• pp.29-40
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• 1996

We had designed and made the cylindrical ionization chamber which operated above 5 mR/h. Using commercial electrometer, we investigated the characterictic of charge collection in the ion chamber. The active volume was 190.4㎤ and overall length and diameter in the chamber was 15.5cm, 5.22cm, respectively. The chamber had three electrodes(inner, central, wall electrode). And background current was 8.39${\times}$10$\^$-14/${\pm}$1.5${\times}$10$\^$-15/A to arrange the electrodes which were coaxial in chamber axis. The collection efficiency of chamber for Cs$\^$137/ was 99.7％ when the opreating voltage was applied 400V. Comparing with the commertial dosimetry system, the exposure calibration constant was 4.531${\times}$19$\^$7/R/C. By normalizing to CS$\_$137/ the relative energy response of the chamber was 1.30 for Am$\_$24/, 1.05 for C0$\_$60/, respectively. When the irrarition tranversed to the chamber axis, the isotropic effect of the chamber was not considerable.

• Korean Journal of Pharmacognosy
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• v.47 no.1
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• pp.62-72
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• 2016

Banhasasim-tang is a well-known traditional Korean herbal formula and has been used clinically for the treatment of gastric disease, including acute and chronic gastritis, diarrhea and gastric ulcers in Korea. In this study, an ultra-performance liquid chromatography-electrospray ionization-mass spectrometer method was developed for the quantitative determination of the 13 marker constituents, homogentisic acid (1), 3,4-dihydroxybenzaldehyde (2), spinosin (3), liquiritin (4), baicalin (5), ginsenoside Rg1 (6), liquiritigenin (7), wogonoside (8), ginsenoside Rb1 (9), baicalein (10), glycyrrhizin (11), wogonin (12), and 6-gingerol (13) in Banhasasim-tang decoction. Separation of the compounds 1-13 was using 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) formic acid in water (A) and acetonitrile (B) by gradient elution. The injection volume and flow rate were $2.0{\mu}L$ and 0.3 mL/min, respectively. Calibration curves of the compounds 1-13 were showed with $r^2$ values ${\geq}0.9908$. The limit of detection and limit of quantification values of the compounds 1-13 were 0.04-1.11 ng/mL and 0.13-3.33 ng/mL, respectively. Among the these compounds, the compounds 1-3 were not detected, while the compounds 4-13 were detected in the ranges of $3.20-107,062.98{\mu}g/g$ in Banhasasim-tang sample.

• Progress in Medical Physics
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• v.12 no.2
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• pp.141-146
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• 2001

It is well known that assurance of the radiation therapy needs for an accuracy of $\pm$ 5 % in the delivery of an absorbed dose to target volume. Therefore, the dose evaluation of brachytherapy source and/or linear accelerate beam must be a stability with accuracy. In an advanced country, they recommended to use the radioactive check source for reference air ionization chamber for a stable response of radiation field chamber. In this experiments, the radioactive source Sr-90 and PR-05 air ionization chamber were used for standard source and reference ion chamber. The response of reference ion chamber showed as an 1.000$\pm$ 0.010 uncertainty for 10 years long and the evaliuation f dose discrepancy of clinical field ion chamber showed as 0.997 $\pm$0.011 in a $^{60}$ Co brachytherapy soruce. In our experiments, we can assuarance the long halflife standard source is reliable to preserve the calibration factor of reference chamber in stability.

• YAKHAK HOEJI
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• v.60 no.2
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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.

• Natural Product Sciences
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• v.22 no.2
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• pp.93-101
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• 2016

For efficient quality control of the Samryeongbaekchul-san decoction, a powerful and accurate an ultra-performance liquid chromatography (UPLC) coupled with electrospray ionization (ESI) tandem mass spectrometry (MS) method was developed for quantitative analysis of the thirteen constituents: allantoin (1), spinosin (2), liquiritin (3), ginsenoside Rg1 (4), liquiritigenin (5), platycodin D2 (6), platycodin D (7), ginsenoside Rb1 (8), glycyrrhizin (9), 6-gingerol (10), atractylenolide III (11), atractylenolide II (12), and atractylenolide I (13). Separation of the compounds 1 - 13 was performed on a UPLC BEH $C_{18}$ column ($2.1{\times}100mm$, $1.7{\mu}m$) at a column temperature of $40^{\circ}C$ with a gradient solvent system of 0.1% (v/v) formic acid aqueous-acetonitrile. The flow rate and injection volume were 0.3 mL/min and $2.0{\mu}L$. Calibration curves of all compounds were showed good linearity with values of the correlation coefficient ${\geq}0.9920$ within the test ranges. The values of limits of detection and quantification for all analytes were 0.04 - 4.53 ng/mL and 0.13 - 13.60 ng/mL. The result of an experiment, compounds 2, 6, 12, and 13 were not detected while compounds 1, 3 - 5, and 7 - 11 were detected with 1,570.42, 5,239.85, 299.35, 318.88, 562.27, 340.87, 12,253.69, 73.80, and $115.01{\mu}g/g$, respectively.