• 한국식품위생안전성학회지
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• 제21권2호
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• pp.82-91
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• 2006

식품첨가물공전의 일반시험법 중 납시험법에 대하여 국내에 유통되는 식품첨가물을 대상으로 한국, 일본, JECFA, 미국 및 EU의 규격 및 시험법에 따라 비교 분석하였다. 식품첨가물의 납 함량을 분석하는 방법으로서 한국은 비색법에 의한 디티존법을 채택하고 있으며, 일본은 원자흡광도측정법(분광광도계법)을, 미국은 디티존법(비색법), 원자흡광도측정법(분광광도계법), 원자흡광도측정법(흑연로법), APDC 추출법 등 4가지의 방법을, JECFA와 EU는 디티존법(비색법), 원자흡광도측정법(분광광도계법)을 채택하고 있다. 한국, 미국 및 JECFA의 디티존법은 거의 동일하였으며, 미국, JECFA및 EU는 검체의 종류에 따라 사용하는 방법을 개별 품목에 별도로 나타내고 있다. 국내에서 유통되는 112.스테아린산마그네슘 등 화학적합성품 13품목과 5.구아검 등 천연첨가물 12품목 등 검체의 납함량을 각 기관의 분석방법에 따라 분석한 결과 모두 각 기관의 규격 및 기준에 적합한 것으로 나타났으며, 시험 및 조작방법상의 문제점도 나타나지 않았다.

• 산업기술연구
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• 제16권
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• pp.169-174
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• 1996

Microstructural analyses of synthetic arsenic-containing heavy metal sludges solidified with Portland cement were performed. Heavy metal sludges containing 0.04M of cadmium, chromium, copper, lead, and arsenic were prepared by sodium hydroxide precipitation and successive vacuum filtration. The sludges mixed with cement were cured for 14 days. The solidified sample was characterized by 1) leaching test, 2) scanning electron microscopy and 3) X-ray diffractometry. Of the metals tested, only Pb concentration in the leachate exceeded the Korean regulatory limit. The level of lead in the leachate was as high as 10 times the regulatory limit. X-ray analysis suggested that the metal hydroxides might be present in complex or impure crystalline phases.

• 산업기술연구
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• 제22권B호
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• pp.89-93
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• 2002

When testing products before shipment to the customer, quality characteristics are measured to decide whether or not their values are between the specification limits. Unfortunately, this testing procedure can lead to incorrect decisions because of gauge error. That is, good products can erroneously be qualified as bad, and bad products as good, and this has consequences for producer's and consumer's risk. In cases of such as this, the compressed gauge limit can be used to achieve the desired product quality level dictated by the manufacturer or the customer. A compressed gauge limit is a limit set by the manufacturer on a test gauge that is tighter than the specification limit established by the customer. The compressed gauge limits should be set at levels to achieve the defect levels desired by the customer and simultaneously minimize the loss of good product that is rejected due to errors in the gauges. In this article, the models for determining the defect levels and the losses obtained by adding compressed gauge limits will be developed. A response surface model approach is utilized which allows an optimal operating condition to be generated relatively easily.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.195-198
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• 2004

This study applied EK method to remediate contaminated soil by heavy metal(Pb), tried to increase the efficiency of remediation using zeolite as enhanced EK remediation method to overcome the limit of traditional EK remediation method. Adsorption tests on Pb were conducted to apply the EK extraction and test conditions which contained the electrode reversal, operating time were established. After tests, lead-ions were transported into the specific position of zeolite by EK phenomena, then the immobilization of lead-ions at zeolite was developed. Based on these tests, the efficiency of remediation is different with its test conditions. In addition, the efficiency of remediation was improved dramatically by adding zeolite without electrode reversal and satisfied TCLP regulation of EPA in USA through the whole sample range. Finally, absorption and immobilization capacity of zeolite were proved its excellence and confirmed the possibility of application as enhanced EK remediation method.

• 항공우주시스템공학회지
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• 제9권1호
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• pp.28-34
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• 2015

Armed aircraft of a basic trainer class installs external stores under wing box by using pylon and performs an operation such as weapon delivery and jettison, and should be designed to withstand all kinds of loads applied to external stores. The static strength test of pylons and wing box was performed to assess the static strength of pylon and their support structures for substantiation. Based on the test, the structures were verified to fully satisfy a given design requirement. In this paper, methods of test load generation of wing box and pylon, evaluation of test result data and design result of test set-up were presented. Comparing the FEM analysis with the same test data can lead to good match and reasonable deviation between both. Finally, based on the test and the analysis, the static strength of test article was substantiated and the reliability and effectiveness of analysis math model were obtained.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.235-240
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• 2001

The CHFG (Critical Heat Flux in Gap) test results have been evaluated to quantify the critical power in hemispherical narrow gaps and a new correlation has been developed. The CHFG test results have shown that increases in the gap thickness and pressure lead to an increase in critical power. The pressure effect on the critical power was found to be much milder than predictions by CHF correlations of other researches. From the CHFG test results, a new correlation on critical power in the hemispherical gap has been developed using the non-dimensional parameters as follows: $$\frac{qCHF}{{\rho}g^hfg}{\cdot}4\sqrt{\frac{{\rho}_g^2}{g{\sigma}{\Delta}{\rho}}=\frac{0.1042}{1+0.1375({\rho}g/{\rho}l)^{0.21}(D/s)}$$ The developed correlation has been expanded to apply the spherical geometry using the Siemens/KWU's correlation.

• 한국포장학회지
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• 제14권1호
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• pp.35-42
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• 2008

국내에서 유통 중인 NY/PE 또는 NY/LLDPE, PETP/PE와 PVDC 재질의 총 28가지 식품용 공기차단성 합성수지 필름들을 수집하여 증발잔류물(총이행량), 항산화제, 과망간산칼륨소비량, 중금속, 그리고 가소제에 대한 재질실험과/또는 용출실험을 함으로써 이들 포장재들이 국내 기준규격에 적합한지 여부와 안전성 수준을 파악하였다. 지방성식품모사용매로서 n-heptane을 이용하여 측정한 총이행량의 평균값은 NY/PE 또는 NY/LLDPE, PETP/PE와 PVDC에서 각각 7.6, 6.9, 그리고 14.1 mg/L이었다. 이러한 총이행량값은 국내 식품공전에 명시된 PE과 PVDC 재질에 대한 기준치인 150과 30 mg/L와 비교하여 매우 낮은 수준이었다. 조사된 거의 대부분의 포장재 시료들에서 Irganox 1010, Irganox 1076과 Irgafos 168같은 항산화제들이 검출되었다. 특정이행량 실험 결과 PVDC를 제외한 모든 시료들에서 Irganox 1076과 Irgafos 168이 이행된 것으로 확인되었는데 Ny/PE/LLDPE(15/25/50 ${\mu}m$) 시료로 Irganox 1076이 216.9 ${\mu}g/g$ 이행된 것이 가장 높은 값이었던 것으로 확인되었다. 조사된 시료들에서 가소제들은 모두 검출한계 이상으로 확인이 불가능하였으며, 과망간산칼륨소비량은 국내 기준치인 10 mg/L보다 훨씬 낮은 수준이었음이 확인되었다. 조사된 모든 재질내 카드뮴과 납의 함량은 국내 기준치인 100 mg/kg보다 매우 낮은 수준이었고 이행량은 검출한계 이하의 값을 보였다. 국내외 관련 법규에서의 국내 식품용 용기포장재에 대한 안전성과 관련한 재질과 용출실험의 기준치를 감안할 때 모든 차단성 합성수지식품 포장재 시료들은 조사된 항목에 대한 현행 기준 규격에 적합한 것으로 확인되었다.

• 펄프종이기술
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• 제39권5호
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• pp.45-51
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• 2007

This study was carried out to investigate various heavy metal contents in packaging papers by pre-treatments for ICP-ES (Inductively Coupled Plasma Emission Spectrometry) analysis. Pre-treatment methods of heavy metals in this study include extraction, migration and decomposition methods (dry ashing, $HNO_3-HClO_4-HF,\;HNO_3,\;and\;H_2SO_4-HNO_3$). Test results were compared with conventional extraction (water) and migration (3% acetic acid) methods. The five representative heavy metals (Cd, As, Pb, Cr and Hg) were analyzed. For Cd, Hg, and As, the results were below detection limit of the instrumental technique. It was considered that the migration test was a better method compared to extraction test, but all the decomposition methods showed much higher detection values than the extraction or migration test. In case of recycled corrugated containers, 3% acetic acid solution extracted about 25% of chromium and 30% of lead compared to the content by decomposition methods. Among all decomposition methods, the nitric acid - perchloric acid - hydrofluoric acid treatment brought a slightly higher detection value than others, but there was no significant difference among them except sulfuric acid - nitric acid method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 춘계학술대회 논문집
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• pp.381-385
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• 2014

This paper investigates the magneto-rheological(MR) mount for the marine diesel-generator(D/G) sets. Sometimes, significant vibrations over the allowable limit are observed on the D/G sets due to their huge excitation forces. Because the severe vibration can lead to structural damages to the D/G sets, it should be reduced below the limit. Although passive mounts with rubber isolators are usually used, the vibration reduction performance is not always sufficient. In addition, expecting that the vibration levels required by customers will get more severe, vibration reduction devices need to be developed. To the aim, the flow mode type of MR mount has been designed. Especially, the annular-radial configuration was adopted to enhance the damping force within the restricted space. The geometry of the mount has been optimized to obtain the required damping force and the magnetic field analysis has been carried out using ANSYS APDL. To verify the performance of the developed MR mount, an excitation test was conducted. In addition, they were applied to a medium-speed diesel generator and it was verified that about 40% of vibration reduction was yielded.

• 대한방사선기술학회지:방사선기술과학
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• 제45권2호
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• pp.159-164
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• 2022

The study developed a radiation dose measurement program in the radiology laboratory to measure how much exposure the students are exposed to during the radiology class, to request for the improvement and the revision of the current Nuclear Safety Act. The experimental program is shown in the following figure, and experiments were conducted to determine the degree of radiation exposure in the control room with a lead gown at a distance of 1 m, 2 m, and 1 m, and in a control room with a radiographic lead glass wall. The duration of the experiment was 3 months from April to June, when radiation imaging practice classes were conducted, and 128 hours of imaging practice per month were conducted. In order to find out the dose of radiation dose during radiology imaging practice class, the experiment was carried out from April to June for 3 months, and according to the program, the results of exposure dose were 0.34 mSv at 1 m distance, 0.01 mSv at shielding of lead gown at 1 m distance, 0.16 mSv at 2 m distance, and 0.01 mSv at control room with radiation lead glass wall. The exposure dose from the test results was much below the annual general public limit dose of 1 mSv. The restriction on the operation of the radiation equipment in the practice of the students is a regulation that infringes the right of students to learn, and amendments or exemptions of Nuclear Safety Act should be enacted to ensure that it does not violate the fundamental right to learn for students in radiology.