• Nuclear Engineering and Technology
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• 제27권2호
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• pp.234-247
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• 1995

Trace elements in airborne particulates were analyzed by instrumental neutron activation analysis (INAA) under the optimum analytical condition. Neutron irradiation for sample was done at the irradiation hole(neutron flux 1$\times$10$^{13}$ n/$\textrm{cm}^2$.s) of TRIGA MARK-III research reactor in the Korea Atomic Energy Research Institute. For the verification of the analytical method, NIST SRM-1648 and NIES CRM No.8 ore chosen and analyzed. The accuracy and precision of the analysis of 40 and 24 trace elements in the samples were compared with the certified and reported values, respectively. The analytical method was found to be reliable enough when the analytical data of NIES sample were compared with those of different counties. In the analytical result of two or both of standard reference materials, relative standard deviation wes within the 15％ except a few elements and the relative error was within the 10％. We used this method to analyze 30 trace elements in airborne particulates collected with the high volume air sampler(PM-10) at too different locations and also confirmed the possibility to use this method as a routine monitoring tool to find out environmental pollution sources.

• 한국정밀공학회지
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• 제15권7호
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• pp.149-159
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• 1998

The importance of soundness and safety evaluation in weld zone using by the ultrasonic wave has been recently increased rapidly because of the collapses of huge structures and safety accidents. Especially, the ultrasonic method that has been often used for a major non-destructive testing(NDT) technique in many engineering fields plays an important role as a volume test method. Hence, the defecting any defects of weld Bone in austenitic stainless steel type 304 using by ultrasonic wave and neural network is explored in this paper. In order to detect defects, a distance amplitude curve on standard scan sensitivity and preliminary scan sensitivity represented of the relation between ultrasonic probe, instrument, and materials was drawn based on a quantitative standard. Also, a total of 93％ of defect types by testing 30 defect patterns after organizing neural network system, which is learned with an accuracy of 99％, based on ultrasonic evaluation is distinguished in order to classify defects such as holes or notches in experimental results. Thus, the proposed ultrasonic wave and neural network is useful for defect detection and Ultrasonic Non-Destructive Evaluation(UNDE) of weld zone in austenitic stainless steel 304.

• 핵의학기술
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• 제21권2호
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• pp.28-30
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• 2017

본 연구를 통해 항 GAD 항체검사에서 뇌척수액에 대한 정상치 범위를 추정하였다. 본원에서 211명을 대상으로 혈청과 뇌척수액에 대한 항 GAD 항체검사를 함께 의뢰받은 환자 데이터를 분석해 본 결과 혈청은 1.0 U/mL 이상의 값을 가진 환자가 약 5%를 차지하였고. 뇌척수액의 경우에는 1.0 U/mL이상의 값을 가진 환자는 약 98% 이상을 차지하였다. 혈청의 참고치 (1.0 U/mL 이상 양성)를 뇌척수액에 적용했을 경우에는 대부분의 환자들이 강직증후군 및 간질을 진단 받게 된다. 이에 혈청과 뇌척수액의 참고치를 병용해서 사용하는 것은 부적합하다고 판단하였고 뇌척수액에 대한 참고치를 본원에서 자체적으로 설정하고자 하였다. 실험 대상으로는 정상인의 뇌척수액을 채취하는 데는 어려움이 있어 이와 가장 유사한 생리식염수를 음성대조군으로 선정하였다. 총 70개의 생리식염수를 검사한 결과 Mean값이 1.97 U/mL, SD 값이 0.72 U/mL가 나왔다. 이 값들에 Hoffmann법으로 Mean값에서 ${\pm}2SD$를 정상범위로 하여 0.54 U/mL ~ 3.40 U/mL로 Expected reference range를 설정할 수 있었다. 본 실험에서 아쉬운 점은 참고치 설정에 있어 정상인의 뇌척수액으로 검사가 이루어지지 못한 부분이다. 앞으로 정상인의 뇌척수액으로 참고치 설정을 할 수 있다면 보다 더 정확하게 임상적으로 적용할 수 있을 것이라 생각 된다.

• Journal of Radiation Protection and Research
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• 제41권4호
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• pp.359-367
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• 2016

Background: As new legislation has come into force implementing radiation safety management for the use of naturally occurring radioactive materials (NORM), it is necessary to establish a rapid and accurate measurement technique. Measurement of $^{238}U$ and $^{232}Th$ using conventional methods encounter the most significant difficulties for pretreatment (e.g., purification, speciation, and dilution/enrichment) or require time-consuming processes. Therefore, in this study, the applicability of ED-XRF as a non-destructive and rapid screening method was validated for raw materials and by-product samples. Materials and Methods: A series of experiments was conducted to test the applicability for rapid screening of XRF measurement to determine activity of $^{238}U$ and $^{232}Th$ based on certified reference materials (e.g., soil, rock, phosphorus rock, bauxite, zircon, and coal ash) and NORM samples commercially used in Korea. Statistical methods were used to compare the analytical results of ED-XRF to those of certified values of certified reference materials (CRM) and inductively coupled plasma mass spectrometry (ICP-MS). Results and Discussion: Results of the XRF measurement for $^{238}U$ and $^{232}Th$ showed under 20% relative error and standard deviation. The results of the U-test were statistically significant except for the case of U in coal fly ash samples. In addition, analytical results of $^{238}U$ and $^{232}Th$ in the raw material and by-product samples using XRF and the analytical results of those using ICP-MS ($R^2{\geq}0.95$) were consistent with each other. Thus, the analytical results rapidly derived using ED-XRF were fairly reliable. Conclusion: Based on the validation results, it can be concluded that the ED-XRF analysis may be applied to rapid screening of radioactivities ($^{238}U$ and $^{232}Th$) in NORM samples.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2940-2944
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• 2015

화순항에서 유효활용을 위한 준설토의 오염도 분석결과, Ni이 기준치를 전지점에서 초과하는 것으로 나타났다. 그러나 개정된 유효활용기준에 의하면 기준치를 초과하더라도 인위적인 오염원이 없고 펄의 평균 무게 비율이 10%미만이며 생태독성 시험을 통과하였을 경우 양빈재로 활용이 가능하다. 따라서 연구방법으로 해양환경공정시험법에 의한 펄의 평균무게 비율조사와 생태독성실험을 실시하였다. 펄의 평균 무게 비율은 5.37%로 기준치인 10%을 하회하는 것으로 조사되었다. 발광 박테리아를 이용한 생태독성실험 결과는 상대발광저해율이 0~9.13%로 독성없음으로 판정되었으며 저서성 단각류를 이용한 시험에서도 대조구와 시료의 상대평균생존률이 0%로 독성없음으로 판정되었다 따라서, 개정된 유효활용기준을 모두 만족하므로 양빈재로 사용이 가능한 것으로 적합성이 평가되었다.

• 한국염색가공학회지
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• 제30권3호
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• pp.190-198
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• 2018

We fabricated high transmission and high scattering poly(ethylene-co-vinyl acetate)(EVA) films embedding $SiO_2$ nanoparticles to improve outcoupling efficiency in organic display. The 800nm diameter $SiO_2$ nanoparticles aggregated and formed $1.56{\mu}m$ (with ${\pm}0.853{\mu}m$ standard deviation) diameter microparticles in EVA. The total transmission of scattering film was 83.3% on Polyethylene terephthalate(PET), which was higher than reference 82.8% PET substrate. The diffuse transmission and haze of the $SiO_2$ embedded EVA film were 76.1% and 91.4%, respectively. The optimized condition was 1:1 weight ratio of $SiO_2$ nanoparticles to EVA in Tetrahydrofuran(THF) solution. When the ratio of $SiO_2$ was larger than 1, the total transmission decreased by the increase in backscattering of light due to high scattering. With the optimized condition, we could succeed to fabricate a large scale film(35m in length) with a roll-to-roll process.

• Journal of Preventive Medicine and Public Health
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• 제28권4호
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• pp.863-873
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• 1995

This report describes a preperation and characterization of canine blood lead(Pb) standard reference material(SRM). Three adult beagle dogs(A, B, and C)were orally dosed with gelatin capsules containing $Pb(NO_3)_2$, equivalent to $10\sim80mg$ Pb/kg body weight. Blood was drawn 24 hours after the dose from the cephalic vein into lead free 500ml Pyrex beaker in which EDTA.K was contained as an anticoagulant. The amount of lead given to individual dog was varied arbitrarily. Three month later, 3 canine animals were orally dosed with lead secondarily to make mixed SRM(D1) which was mixed different concentrations of lead in bloods with A1, B1, and C1 in vitro. The SRMs for A, B, C, A1, B1, C1, and D1 were distributed 2ml each into more than 300 lead free bottles, and were stored in refregerator at $4^{\circ}C$. The amount of lead in canine whole blood samples were determined using a Varian 30A atomic absorption spectrophotometer(AAS) with a model GTA-96 graphite tube atomizer with D2 background correction and a Hitachi Z-8100 AAS with Zeeman background correction. The sensitivity and detection limits for lead determination of Varian 30A were $0.46{\mu}g/L,\;0.34{\mu}g/L,\;and\;0.56{\mu}g/L,\;0.14{\mu}g/L$ of Hitachi Z-8100, respectively. Day to day variations in determination of blood lead concentration in a certain sample were $31.11{\pm}1.36{\mu}g/100ml$ by Varian 30A, and $33.08{\pm}0.82{\mu}g/100ml$ by Hitachi Z-8100, showing the difference of 3% between the two results. At the blood lead concentrations of $56.31{\pm}1.98{\mu}g/100ml(A),\;40.89{\pm}0.80{\mu}g/100ml(B),\;59.01{\pm}1.38{\mu}g/100ml(C)$, the precisions of replicated measurements by AAS were 3.52%, 1.96%, and 2.34%, respectively. Coefficient variation(CV) of SRMs(A, B, and C) within a standard sample were ranged from 0.92% to 7.50%, and those between 5 standard samples were 1.21%, 2.64%, and 1.11%, respectively, showing inter-vial variation of $1{\mu}g/100ml$. Lead levels in SRMs during one month storage were unchanged. The overall recoveries were $89.6\sim100.4%,\;91.6\sim101.9%,\;90.3\sim100.0%$ for A, B, and C SRMs, means were $56.46{\pm}2.69{\mu}g/100ml,\;39.35{\pm}1.89{\mu}g/100ml,\;57.40{\pm}2.31{\mu}g/100ml$, and measurement ranges were$52.88{\pm}59.26{\mu}g/100ml,\;37.47{\pm}41.68{\mu}g/100ml,\;54.80{\pm}60.69{\mu}g/100ml$, respectively. Those results were laid within confidence limits values. The lead concentrations in the mixed sample(D1) stored over one month period were ranged from $32.76{\mu}g/100ml\;to\;33.54{\mu}g/100ml$, with CV ranging from 1.2% to 2.7%. The results were similiar to each of single samples(A1, B1, and C1) in respect of homogeneity and stability. Results of the mixed blood sample analysed after 1 month storage at $4^{\circ}C$ by four other laboratories(L1, L2, L3, L4) were similar with those of our laboratory($L5;31.18{\pm}0.24{\mu}g/100ml$, acceptable range by $CDC;25.18\sim37.18{\mu}g/100ml$), showing the concentrations of $25.91{\pm}1.19{\mu}g/100ml(L1),\;34.16{\pm}0.22{\mu}g/100ml(L2),\;35.68{\pm}0.85{\mu}g/100ml(L3),\;30.95{\pm}0.46{\mu}g/100ml(L4)$ in a each samples.

• 복식문화연구
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• 제15권5호
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• pp.737-748
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• 2007

Korea is now entering into aging society next to Japan in Asia, which is considered as unusual in the semi-developed countries. More than 50 year-old consumer market is anticipated to grow to 28.7% of the total in 2010 from 20.4% in 2000. In particular, the silver market is estimated to be formed in full range in 2010 when the generation born in 50s and 60s after the Korean War start to retire. In this study, body shapes are classified as standard, obese, and tiny according to the previous studies based on the body shape characteristics and the body measurement of the Elderly Women. Based on the classification, we developed pattern of the panty for the obese Elderly Women to provide basic materials for the quality enhancement of the clothing of the increasing Elderly Women. The followings are the result of the study 1. To categorize the body shapes of the Elderly Women focusing on the lower half, we grouped the target subjects using the nested approach by the average standard deviation and the factor analysis minimal diffusion method. Accordingly, type 1 and 2 had 36 members respectively and type 3 had 43 members. In this study, two Elderly Women subjects with standard body shape falling under the type 1 were selected as the subjects. 2. In the second trial evaluation for the panty pattern for the Elderly Women 32 items for appearance test and 3 items for functional test were evaluated. The scores in leg, sideline and hip were shown high and the balance between the parts was maintained very well. In the functional test, the panty used to be too tight for the leg curve but in the second trial it was improved, too. In each item, the second trial test showed better score than the first trial test. Conclusively, the most optimal panty prototype for the Elderly Women was proposed according to the trial test result.

• 환경분석과 독성보건
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• 제21권4호
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• pp.229-236
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• 2018

In this study, inter-laboratory comparison was done using elemental analyzer-isotope ratio mass spectrometers (EA-IRMSs) to determine carbon and nitrogen contents as well as stable carbon and nitrogen isotopic compositions (${\delta}^{13}C$ and ${\delta}^{15}N$) of five environmental samples containing lake and marine sediments, higher plant leaves, and fish muscle, and one organic analytical standard (Protein (Casein) Standard OAS). Five national laboratories participated in this comparison study, and each laboratory analyzed all five samples and the analytical standard. Results showed that variations in total organic carbon (TOC) and total nitrogen (TN) contents as well as ${\delta}^{13}C_{TOC}$ and ${\delta}^{15}N_{TN}$ values among the laboratories were large compared to the analytical uncertainties. The results highlighted the inhomogeneity of the test samples and thus, the need to select suitable standard reference materials for future inter-laboratory studies. Further inter-laboratory comparison exercises could promote good measurement practices in the acquisition of stable carbon and nitrogen isotopic composition data.

• Korean Journal of Radiology
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• 제23권1호
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• pp.139-149
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• 2022

Objective: To compare the effects of bone suppression imaging using deep learning (BSp-DL) based on a generative adversarial network (GAN) and bone subtraction imaging using a dual energy technique (BSt-DE) on radiologists' performance for pulmonary nodule detection on chest radiographs (CXRs). Materials and Methods: A total of 111 adults, including 49 patients with 83 pulmonary nodules, who underwent both CXR using the dual energy technique and chest CT, were enrolled. Using CT as a reference, two independent radiologists evaluated CXR images for the presence or absence of pulmonary nodules in three reading sessions (standard CXR, BSt-DE CXR, and BSp-DL CXR). Person-wise and nodule-wise performances were assessed using receiver-operating characteristic (ROC) and alternative free-response ROC (AFROC) curve analyses, respectively. Subgroup analyses based on nodule size, location, and the presence of overlapping bones were performed. Results: BSt-DE with an area under the AFROC curve (AUAFROC) of 0.996 and 0.976 for readers 1 and 2, respectively, and BSp-DL with AUAFROC of 0.981 and 0.958, respectively, showed better nodule-wise performance than standard CXR (AUAFROC of 0.907 and 0.808, respectively; p ≤ 0.005). In the person-wise analysis, BSp-DL with an area under the ROC curve (AUROC) of 0.984 and 0.931 for readers 1 and 2, respectively, showed better performance than standard CXR (AUROC of 0.915 and 0.798, respectively; p ≤ 0.011) and comparable performance to BSt-DE (AUROC of 0.988 and 0.974; p ≥ 0.064). BSt-DE and BSp-DL were superior to standard CXR for detecting nodules overlapping with bones (p < 0.017) or in the upper/middle lung zone (p < 0.017). BSt-DE was superior (p < 0.017) to BSp-DL in detecting peripheral and sub-centimeter nodules. Conclusion: BSp-DL (GAN-based bone suppression) showed comparable performance to BSt-DE and can improve radiologists' performance in detecting pulmonary nodules on CXRs. Nevertheless, for better delineation of small and peripheral nodules, further technical improvements are required.