• The Bulletin of The Korean Astronomical Society
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• 제41권1호
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• pp.71.3-72
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• 2016

운동학적으로 측정된 질량과 측광으로 측정된 질량이 불일치하는 질량 불일치 문제는 현대천문학의 중요한 문제이다. 현재 이러한 질량 불일치에 대한 두 가지 해결책이 제시 되었다. 하나는 현대 표준우주론인 ${\Lambda}CDM$ 패러다임의 핵심 요소인 암흑물질, 다른 하나는 Milgrom에 의해 제시된 수정된 뉴턴역학(Modified Newtonian dynamics: MOND)이다. 두 방법에 대한 많은 연구가 진행되었는데, 최근 연구 결과에 의하면 나선형 은하의 회전속도 윤곽은 MOND와 잘 부합하나 타원은하에 대해서는 불명확하다. 여기서 우리는 ATLAS3D project 에서 얻어진 260개의 조기형 은하 중 거의 원형인 11개의 타원은하들을 선별하여 표준패러다임(뉴턴역학과 암흑물질)과 MOND 하에서 속도분산 윤곽에 대한 모델링을 수행하였다. 속도분산 anisotropy에 대한 parametric 모형을 가정하고 다음의 결과를 얻었다. (1) anisotropy가 속도분산 윤곽에 큰 영향을 준다는 것을 확인하였고, (2) 전체적으로 표준패러다임과 MOND 중 어느 패러다임이 관측된 속도분산 윤곽에 더 잘 부합하는지 결론을 도출하기가 어려웠고, (3) 은하 개별적으로는 표준패러다임 하에서 요구되는 암흑물질의 양이 달랐고, 선호되는 MOND 모형에서도 미세한 차이가 나타나는 것으로 보였다. 이 결과는 anisotropy에 대한 더 나은 이해를 바탕으로 개선될 수 있을 것이다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 한국환경과학회 2019년도 정기학술대회 발표논문집
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• pp.199-199
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• 2019

• The Monthly Technology and Standards
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• 통권101호
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• pp.26-27
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• 2010

유해물질제한지침(RoHS)의 제6조항에 따라 유럽위원회가 지침을 재검토 중이다. 유럽의회는 RoHS 규제에 현 8종의 전기전자 제품군에서 모든 제품으로의 규제 시행 확대와 기존 4종의 중금속과 2종의 난연제 규제에서 브롬계 난연제, 크롬계 난연제, PVC, 유해 플라스틱 첨가제 등의 즉각적 규제를 목표로 하고 있다.

• Analytical Science and Technology
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• 제37권3호
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• pp.166-173
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• 2024

Steroids have a temporary skin improvement and whitening effect by controlling vasodilation, but they also cause side effects when used for a long time. Therefore, steroids were designated and managed as raw materials that cannot be used in cosmetics in Korea. However, steroids are continuously being detected in cosmetics, causing social issues. In this study, we developed a certified reference material (CRM) for the determination of steroids such as hydrocortisone in cosmetics. A cream-type cosmetic CRM was manufactured and subsequently certified following the guidelines outlined in ISO Guide 35. Homogeneity, short-term stability, and long-term stability were evaluated using isotope dilution mass spectrometry (ID-MS). The certified values were determined by using NIST's primary reference material to ensure traceability. From now on, we intend to supply the certified reference material as a cosmetic CRM to national and international companies, as well as research institutes after certification as certified reference material from KOLAS and registering on COMAR.

• Analytical Science and Technology
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• 제25권5호
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• pp.273-283
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• 2012

Phthalate plasticizers are regulated by RoHS, REACH and CPSC as hazardous substances. Responding to these international environmental restrictions, we developed ABS certified reference material (CRM) for determination of phthalate plasticizers such as DMP, DEP, DBP, BBP, DEHP and DnOP. The candidate material has been made with ABS resin widely used in electric and electronic products and 6 kinds of phthalate plasticizers. The making of the material involved a series of processes like extruding, cooling, pelletizing, and drying using twin screw extruder. Then it has been certified according to ISO Guide 35. Using isotope dilution-gas chromatography/mass spectrometry (ID-GC/MS), homogeneity, short-term stability, and long-term stability were evaluated. The certified values were determined by using primary reference material (PRM) of KRISS for traceability. From now on, we will provide ABS CRM to national and international companies and research institutes after certification as certified reference material and registering on COMAR (code of reference material).

• Journal of the Korean Vacuum Society
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• 제11권4호
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• pp.218-224
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• 2002

A domestic round robin test(RRT) for the quantitative analysis of minor impurities was performed by a standard procedure and standard reference material. The certified reference material(CRM)s for B-doped Si thin film and analysis specimens and the analysis specimens were prepared by an ion beam sputter deposition method. These samples were certified by inductively coupled plasma mass spectrometry(ICP-MS) with isotope dilution method which il one of the most quantitative methods in chemical analysis. By using an international standard procedure(ISO/DIS-l4237) for the quantitative analysis of B in Si by SIMS, a domestic RRT was performed for these specimens. Although only a few laboratories participated in this RRT, the average B concentration well agreed with the certified value within 2% error.

• Analytical Science and Technology
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• 제13권5호
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• pp.565-572
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• 2000

In this paper it was described on the standards for Xe analysis by Wavelength Dispersive X-ray Spectrometer (WDS) of Electron Probe Micro Analyser. According to the experimental results, CsI and $BaCO_3$ are appropriate compounds as standard specimen for Cs, I and Ba which has not suitable pure metal standards. In the beam current of 10-30 nA range, the Cs x-ray intensity measured from CsBr and CsI was proportional to the beam current. It was found that the linear regression factor R, showing the linearity between the atomic number and x-ray intensity between In and Nd elements, was higher than 0.99 at 25 kV and PET crystal. The caJlculated x-ray intensity of Xe standard from this linear regression equation was 1.095 times higher than that ofTe at 25 kV.

• Analytical Science and Technology
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• 제16권4호
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• pp.261-268
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• 2003

To investigate the matrix effect of sample for hydrogen analysis by inert gas fusion-thermal conductivity detection, calibration factor for the hydrogen analyser of the inert gas fusion-thermal conductivity detection method was measured with hydrogen standard materials in Ti, Zr-2.5Nb and by hydrogen gas dosing method. Also the hydrogen extraction efficiency for the different sample matrix, Ti and Zr-2.5Nb, was evaluated without adding tin flux. The calibration factor of the hydrogen analyser which was calibrated by hydrogen standard material in Zr-2.5Nb and Ti was 2~3% and 14% higher than that by hydrogen gas dosing method, respectively. Based on the results of calibration factor measurement, it could be concluded that the hydrogen extraction efficiency of the Ti matrix sample will be 12% lower than that of the Zr-2.5Nb. And according to the experimental results of hydrogen recovery test by no tin flux, the hydrogen recovery percentage of the Ti and Zr-2.5Nb matrix sample was about 70% but the recovery rate of Ti matrix sample was slightly lower than that of Zr-2.5Nb.

• Journal of the Korean Society of Food Science and Nutrition
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• 제24권3호
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• pp.409-414
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• 1995

Antioxidative characteristics of dihydroxyphenylalalnine(DOPA), melanin and enzymatic oxidation products of tyrosine(EOPTs) were studied in a model system. EOPTs were prepared by the tyrosine-tyrosinase reaction at pH 6.5 and $25^{\circ}C$ at various time intervals(0~120min). All EOPTs were brown in varied intensities with increased absorption at 200~210, 280, 310~320nm, and 450~490nm. EOPTs obtaiend at the early stage of the reaction(1~3min especially) showed a higher antioxidative activity than those from the later stage on the inhibition of peroxide, conjugated dienoic acid and malonaldehyde formations in linoleic acid autoxidation. Additionally among the substances of tyrosine, DOPA and melanin, DOPA showed the highest antioxidative activity while that of tyrosine was the lowest during the linoleic acid autooxidation. It was observed that DOPA and melanin had the ability of free radical scavenging, which may party contribute to their antioxidative activity.

• The Korean Journal of Pesticide Science
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• 제20권3호
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• pp.211-220
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• 2016

This study was to develop the analytical reference material of green-pepper for multi-residue analysis of pesticides. According to the ISO Guide 35, ISO Guide 13528 and EURL-PT protocol, the homogeneity, stability, assigned value and uncertainty were calculated to assess if it was suitable to be used as the proficiency test or quality control. The values of the within-bottle standard variation ($s_{wb}$) and the between-bottle standard variation ($s_{bb}$) were 1.7~3.7% of assigned value according to the requirement of the ISO guide 35. And, the uncertainty ($u^*{_{bb}}$) due to inhomogeneity was 0.8~1.1% for all pesticides. The storage stabilities of ten-pesticides at various conditions were assessed. For all target pesticides, the slop ($b_1$) values were smaller than the corresponding values of $[t_{0.95,n-2}{\times}s(b_1)]$ specified by the ISO guide 35, indicating that there were no statistically significant decreases in the concentration of the target pesticides when the analytical reference material was stored at room temperature ($20{\sim}30^{\circ}C$) for 7 days, freezing ($-20^{\circ}C$) for 30 days and deep freezer ($-80^{\circ}C$. except for bifenthrin, fenpropathrin) for 245 days. For proficiency test by using it developed by Korea Institute of Toxicology, inter-lab test was performed with eight organization performing the residual pesticide analysis. We found that there were some different results among them. Some were assessed as questionable or unacceptable for two pesticides and one organization didn't analyze the six pesticides. From these results, this green-pepper analytical reference material containing ten-pesticides could be used as a tool for the proficiency test to improve the reliability or consistency for pesticide residue's results.