• 한국대기환경학회지
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• 제24권1호
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• pp.43-54
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• 2008

Management and control of ammonia at the sources and ambient largely depend on sampling and measurement techniques. Good sampling and measurement techniques provide high quality data. The main purpose of the study is compare the analytical characteristics of the Indolphenol method which is one of the standard method in Korea with automatic analyzers for continued measuring gaseous ammonia. For comparison with other analytical methods, the verification test was designed to evaluate performance parameters; linearity, absorption efficiency, reproducibility and repeatability test, accuracy, and response time test. $R^2$ of calibration curve using IPM and CLM was very high (value is 1.000), but for EcSM $R^2$ value was estimated to be lower than IPM and CLM (as 0.991). The RSD of the CLM ranged from 0.1 to 2.3% over the nine concentration levels measured, %Ds was 0.1 to 10.7%, and average RA over all the measurements was 3.3%. The RSD of IPM and EcSM was ranged from 1.0 to 8.1, 3.9 to 14.0 respectively, and average RA were 8.71, 4.9% respectively. Rise in response times of EcSM was estimated to be 1 minute. It is found to be more sensitive than response time (which ranged from 2 to 9 minute) of CLM. For ammonia concentration measured using the IPM and the CLM from the same ammonia source, linear regression of IPM versus CLM show a slope of 0.805, an intercept of 637 ppb, and $R^2$ of 0.868.

• 분석과학
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• 제18권6호
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• pp.475-482
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• 2005

화학분석 분야에는 ISO 17025에 따른 체계적 품질 관리/보증의 요구가 커지면서, 측정 불확도의 표기가 크게 요구되고 있다. 측정품질의 정량화를 위하여, 화학분석의 QA/QC 문헌들로부터 화학분석 품질에 영향을 미치는 중요한 불확도 요소를 선정하였고, 이것을 측정결과 평가 요소의 기본인 7개의 품질요소로서 반복성, 직선성, 소급성, 변동성, 매질효과, 균질성, 안정성으로 구분하였다. 화학분석의 QA/QC를 위한 이 7대 품질 요소의 측정 모델화, 표준불확도의 계산 및 합성방법을 각각 예로서 제시하였다.

• Natural Product Sciences
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• 제18권3호
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• pp.158-165
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• 2012

A UPLC method for the simultaneous determination of seven compounds was established for the quality control in H. cordata. The UPLC was performed on a $C_{18}$ HSS T3 $2.1{\times}100$ mm, 1.8 ${\mu}m$ column during a 13 minute gradient elution of 0.2% aqueous acetic acid and acetonitrile with the flow rate of 0.2 mL/min at $30^{\circ}C$. The UPLC method was validated according to the ICH guideline of analytical procedures with respect to precision, accuracy, and linearity. The limit of determination and quantitation for the seven compounds were 0.01-0.09 and 0.03-0.28 ${\mu}g/mL$, respectively. The calibration curves of all seven compounds showed good linearity ($r^2$ > 0.999). The intra-day and inter-day the RSD values used to evaluate the precision of analysis were less than 0.9%. The recoveries of quantified compounds ranged from 98.63 to 103.85%. The developed UPLC method was found to be effective, convenient and sensitivity for quantitative analysis of seven compounds in H. cordata. This work could be provided a baseline source for quality control of H. cordata.

• 한국정밀공학회지
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• 제23권8호
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• pp.72-79
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• 2006

We measured grating pitch standards using optical diffractometry and analyzed measurement uncertainty. Grating pitch standards have been used widely as a magnification standard for a scanning electron microscope (SEM) and a scanning probe microscope (SPM). Thus, to establish the meter-traceability in nano-metrology using SPM and SEM, it is important to certify grating pitch standards accurately. The optical diffractometer consists of two laser sources, argon ion laser (488 nm) and He-Cd laser (325 nm), optics to make an incident beam, a precision rotary table and a quadrant photo-diode to detect the position of diffraction beam. The precision rotary table incorporates a calibrated angle encoder, enabling the precise and accurate measurement of diffraction angle. Applying the measured diffraction angle to the grating equation, the mean pitch of grating specimen can be obtained very accurately. The pitch and orthogonality of two-dimensional grating pitch standards were measured, and the measurement uncertainty was analyzed according to the Guide to the Expression of Uncertainty in Measurement. The expanded uncertainties (k = 2) in pitch measurement were less than 0.015 nm and 0.03 nm for the specimen with the nominal pitch of 300 nm and 1000 nm. In the case of orthogonality measurement, the expanded uncertainties were less than $0.006^{\circ}$. In the pitch measurement, the main uncertainty source was the variation of measured pitch values according to the diffraction order. The measurement results show that the optical diffractometry can be used as an effective calibration tool for grating pitch standards.

• 한국식품영양학회지
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• 제30권4호
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• pp.796-803
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• 2017

This study investigated the crude protein and amino acid contents of local agricultural products widely and specifically grown in Korea, including 25 vegetables and 13 fruits. The crude protein content of vegetables and fruits ranged from 0.46 to 6.53% and 0.29 to 2.23%, respectively. Totally, 17 types of amino acids were found in most samples. The total amino acid content of vegetables and fruits ranged from 457.38 to 9,303.18 mg% and 368.82 to 3,118.75 mg%, respectively. The total amino acid contents of garlic and passion fruit was higher compared to other vagetables and fruits. The calibration curves of the standard components showed good linearity ($r^2$>0.99), except Met ($r^2=0.989$). The limits of LOD and LOQ were in the range 0.034 to $0.991{\mu}g/mL$ and 0.009 to $0.474{\mu}g/mL$, respectively. The results of the study can serve as a fundamental source of information regarding crude protein and amino acids contents in food, for diet planning.

• Journal of Radiation Protection and Research
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• 제44권2호
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• pp.79-88
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• 2019

Background: The main goal of experiments is to compare various operational and technical characteristics of D-Shuttle semiconductor personal dosimeters of the Japanese company "Chiyoda Technol Corporation" and Harshaw thermoluminescent dosimeters (TLD) manufactured by "Thermo Fisher Scientific" and DTL-02 of the Russian Research and Production Enterprise (RPE) "Doza" by their occupational and calibration exposure at various dose equivalents from 0.5 to 20 mSv of gamma-radiation. Materials and Methods: Besides dosimeters DTL-02, D-Shuttle and Harshaw TLD, there were also used: (1) the primary reference radionuclide source Hopewell Designs IAEA: G10-1-12 with $^{137}Cs$ isotope (an error is not more than 6% and activity is 20 Ci), and (2) the verification device UPGD-2M of RPE "Doza" and installed in the National Center for Expertise and Certification of the Republic of Kazakhstan (Kapchagai, the National Center for Expertise and Certification). Results and Discussion: The main results of researches are the following: (1) TLDs for Harshaw 6600 and DVG-02TM have an approximately equal measurement accuracy of the individual dose equivalents in the range from 0.5 to 20 mSv of gamma-radiation. (2) Advantages of dosimeters for Harshaw 6600 are due to the high measurement productivity and opportunity to indicate the dose on the skin $H_p$(0.07). Advantages of DVG-02TM consist of operation simplicity and lower cost than of Harshaw 6600. (3) D-Shuttles are convenient for use in the current and the operational monitoring of ionizing radiation. Measurement accuracy and 10% linearity of measurements are ensured when D-Shuttle is irradiated with dose equivalents below 1 mSv at the equivalent dose rate not higher than $3mSv{\cdot}hr^{-1}$. This allows using D-Shuttle at a routine technological activity. Conclusion: The obtained results of experiments demonstrate advantages and disadvantages of D-Shuttle semiconductor dosimeters in comparison with two TLD systems of DVG-02TM and Harshaw 6600.

• 한국정보통신학회논문지
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• 제23권12호
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• pp.1535-1541
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• 2019

방사선 사고 지역 및 제염이 필요한 지역에서의 안전하고 신속한 제염작업을 진행하기 위해서는 방사선 오염원에 대한 다양한 정보 획득이 필요하다. 특히 방사선원의 정확한 위치와 분포 정보의 파악은 신속한 후속 조치 및 오염원 제거를 위해 반드시 필요하며, 작업자의 방사선 피폭을 최소화할 수 있다. 방사선원의 위치와 분포 정보를 획득하기 위해서는 방사선 분포 탐지 장치를 사용한다. 방사선 분포 탐지 장치의 경우 일반적으로 탐지 센서 부가 단일 센서로 구성되며, 단일 센서의 물리적 한계로 인해 탐지 범위가 제한되는 문제점이 있다. 본 논문에서는 방사선 오염 분포 영상화 장치에 사용되는 단일 센서의 탐지 감도 제어를 위하여 보정 검출기를 적용하였으며, 이를 통해 제한적이었던 선량률 탐지 범위를 향상하였다. 또한 감마선 조사 시험을 통해 방사선 분포 탐지 범위의 개선을 확인하였다.

• 한국전기전자재료학회논문지
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• 제35권5호
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• pp.459-465
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• 2022

This paper reports a method to use a wireless sensor network deployed in the field to real-time monitor soil moisture, warning when the moisture level reaches a specific value, and wirelessly controlling an additional device (LED or water supply system, etc.). In addition, we report all processes related to wireless irrigation system, including field deployment of sensors, real-time monitoring using a smartphone, data calibration, and control of additional devices deployed in the field by smartphone. A commercially available open-source Internet of Things (IoT) platform, NodeMCU, was used, which was combined with a 9V battery, LED and soil humidity sensor to be integrated into a portable prototype. The IoT-based soil humidity sensor prototype deployed in the field was installed next to a tree for on-site demonstration for the measurement of soil humidity in real-time for about 30 hours, and the measured data was successfully transmitted to a smartphone via Wifi. The measurement data were automatically transmitted via e-mail in the form of a text file, stored on the web, followed by analyses and calibrations. The user can check the humidity of the soil real-time through a personal smartphone. When the humidity of a soil reached a specific value, an additional device, an LED device, placed in the field was successfully controlled through the smartphone. This LED can be easily replaced by other electronic devices such as water supplies, which can also be controlled by smartphones. These results show that farmers can not only monitor the condition of the field real-time through a sensor monitoring system manufactured simply at a low cost but also control additional devices such as irrigation facilities from a distance, thereby reducing unnecessary energy consumption and helping improve agricultural productivity.

• 대한방사선기술학회지:방사선기술과학
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• 제45권6호
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• pp.553-560
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• 2022

The purpose of this study is to evaluate the clinical risk according to the applicator heterogeneity, mislocation, and tissue heterogeneity correction through a dose verification program during brachytherapy of cervical cancer. We performed image processing with MATLAB on images acquired with CT simulator. The source was modeled and stochiometric calibration and Monte-Carlo algorithm were applied based on dwell time and location to calculate the dose, and the secondary cancer risk was evaluated in the dose verification program. The result calculated by correcting for applicator and tissue heterogeneity showed a maximum dose of about 25% higher. In the bladder, the difference in excess absolute risk according to the heterogeneity correction was not significant. In the rectum, the difference in excess absolute risk was lower than that calculated by correcting applicator and tissue heterogeneity compared to the water-based calculation. In the femur, the water-based calculation result was the lowest, and the result calculated by correcting the applicator and tissue heterogeneity was 10% higher. A maximum of 14% dose difference occurred when the applicator mislocation was 20 mm in the Z-axis. In a future study, it is expected that a system that can independently verify the treatment plan can be developed by automating the interface between the treatment planning system and the dose verification program.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.268-268
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• 2021

Groundwater resource is mostly used in Abomey-calavi (southern region of Benin) as main source of water for domestic, industrial, and agricultural activities. Groundwater intake across the region is not perfectly controlled by a network due to the presence of many private boreholes and traditional wells used by the population. After some decades, this important resource is becoming more and more vulnerable and needs more attention. For a better groundwater management in the region of Abomey-calavi, the present study attempts to predict a future probable groundwater drought using Recurrent Neural Network (RNN) for future groundwater level prediction. The RNN model was created in python using jupyter library. Six years monthly groundwater level data was used for the model calibration, two years data for the model test and the model was finaly used to predict two years future groundwater level (years 2020 and 2021). GRI was calculated for 9 wells across the area from 2012 to 2021. The GRI value in dry season (by the end of March) showed groundwater drought for the first time during the study period in 2014 as severe and moderate; from 2015 to 2021 it shows only moderate drought. The rainy season in years 2020 and 2021 is relatively wet and near normal. GRI showed no drought in rainy season during the study period but an important diminution of groundwater level between 2012 and 2021. The Pearson's correlation coefficient calculated between GRI and rainfall from 2005 to 2020 (using only three wells with times series long period data) proved that the groundwater drought mostly observed in dry season is not mainly caused by rainfall scarcity (correlation values between -0.113 and -0.083), but this could be the consequence of an overexploitation of the resource which caused the important spatial and temporal diminution observed from 2012 to 2021.