• Korean Journal of Environmental Agriculture
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• v.34 no.3
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• pp.230-237
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• 2015

BACKGROUND: To identify the sources of inaccuracy in LC/MS/MS methods used in the routine quantitation of small molecules are described and discussed. METHODS AND RESULTS: Various UPLC coupled to triple quadrupole mass spectrometer and time of flight (TOF) were used to identify the potential sources of inaccuracy and inducing the pitfalls of qualification and quntitation during the veterinary drug residue analysis. Some of stable isotope labelled veterinary drugs, which were used as internal standards, presented "cross-talk", regardless of manufactures of mass spectrometer and types of spectrometer. Group of sulfonamides also presented inaccuracy qualification and quantitation due to the multi-residue analytical method with the same fragment ions at the close retention times. CONCLUSION: The phenomena of "cross-talk" occurring between subsequently monitored transition from stable isotope labelled and isotope non-labelled authentic chemical were identified. To prevent errors and achieve more accurate data during the analysis of small molecules by LC/MS/MS SRM method, Followings should be taken care of and kept checking; purity and concentration of stable isotope as an internal standard, prevention of carry-over during the separation in column, minimizing the ion suppression by matrix effect, identification of retention time, precursor ion and product ion, and full knowledge of data processing including smoothing and peak integration.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4636-4643
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• 2022

A time-of-flight and energy (TOF-E) detection system for the measurement of ²³⁶U accelerator mass spectrometry (AMS) has been developed to improve the ²³⁶U/²³⁸U sensitivity at Micro Analysis Laboratory, Tandem accelerator (MALT), The University of Tokyo. With observing TOF distribution of ²³⁵U, ²³⁶U and ²³⁸U, this TOF-E detection system has clearly separated ²³⁶U from the interference of ²³⁵U and ²³⁸U when measuring three kinds of uranium standards. In addition, we have developed a novel method combining kernel-based density estimation method and multi-Gaussian fitting method to estimate the ²³⁶U/²³⁸U sensitivity of the TOF-E detection system. Using this new estimation method, 3.4 × 10^-12 of ²³⁶U/²³⁸U sensitivity and 1.9 ns of time resolution are obtained. ²³⁶U/²³⁸U sensitivity of TOF-E detection system has improved two orders of magnitude better than that of previous gas ionization chamber. Moreover, unknown species other than uranium isotopes were also observed in the measurement of a surface soil sample, which has demonstrated that TOF-E detection system has a higher sensitivity in particle identification. With its high sensibility in mass determination, this TOF-E detection system could also be used in other heavy isotope AMS.

• Journal of the Korea Institute of Building Construction
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• v.1 no.2
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• pp.146-153
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• 2001

Radical development has been made in the every field of our society for the past scores of year. Radical development of industry and lining environment has mass-produced various toxic wastes . Which comes to the fore as a serious environmental problem. The purpose of this is to suggest the optima mix design by studying the utility of a toxic waste, plated sludge as a building material and deciding the standards of quality and use of cement and evaluating the properties of mortar and concrete in which plated sludge mixed. From an experiment, compressive strength required high early strength cement or special cement. Watertightness proved to be excellent. Heavy metals, such as Cd, Pb, Cu came out below an environmental standard. Cr+6 exceeded an environmental standard under a steam curing, but came out below an environmental under a standard curing. The higher replacement rate was, the lower frost, fusion and resistance were. Thus, got better results above the goal by condition. It was possible that plated sludge was replaced and solidified to aggregate. Therefore, it is necessary to define the standards of quality on strength, replacement rate of wastes, water permeability, endurance in other to solidify plated sludge to concrete products.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.1
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• pp.1-10
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• 2016

Nowadays, the importance of role of the international standardization keeps increasing substantially. We have already known that international standards have a huge impact on many companies, industries and nations. So far, it has been thought that standardizations are needed after the new products come into the market and are mass-produced in order to encourage the use of the products, systems and services. Standardization will make the products more safe, efficient, and environmentally friendly for the users. However, in these days, a paradigm of the standardization has been changed. International standard becomes a tool for dominating global market and is the most important ingredients of the competitiveness and economic progress of the nation and enterprises. Many countries like Japan, Germany and U.S. use the standardization as an effective method to dominate the market and monopolized the new technologies. Therefore, worldwide competition for the standardization of the new technology become fierce. Korea is leading the technology in semiconductor field. However, activities of international standardization are not sufficient. In order to boost the standardization activities in Korea from industry, academia, and research institute, this paper briefly introduce the international standard organization and some critical issues for next-generation semiconductor memory such as flexible semiconductor, automobile semiconductor and wearable devices.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.9
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• pp.724-730
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• 2014

It is essential to control noise and vibration in various industrial fields. In the automobile industry, various plastics have been developed and replaced metallic materials in order to reduce mass and vibration effectively. In this study, we measured and analyzed the Young's moduli and the loss factors of Acrylonitrile butadiene styrene(ABS) and Polypropylene(PP). In order to solve the fundamental error to determine the two quantities, a loudspeaker was used instead of conventional electromagnetic devices to generate bending motion to the specimens and a laser vibrometer was also used in detection of vibration signal of the specimen. The measured Young's moduli and loss factors of the ABS specimen were nearly constant as the temperature($-10{\sim}60^{\circ}C$) was increased. The loss factor of PP specimen showed peak value at $20^{\circ}C$ and it means that there is glass transition for the PP specimen. Young's modulus of PP specimen was linearly decreased as the temperature was increased.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.3
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• pp.115-122
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• 2017

To achieve designed quality and reliability from R&D to force integration, an establishment of precise and distinct specifications and standards are required. However, the recent process of R&D standardization on defense acquisition system, has brought plenty of corrections on specifications and standards that may cause not only difficulties to production line and retardation to the military forces, but also a degradation of provided weapon systems. Therefore, a technical review should be performed by the developer, the producer, and the client, establishing the standard that include mass production requirements as well as clients' requirements. This paper propose a specified solution on process of R&D standardization, by applying a substantial FCA(Functional Configuration Audit) and PCA(Physical Configuration Audit) which implies participation of related agencies. By the improved PCA, 2,023 corrections on 74 types of QAR(Quality Assurance Requirement)s and 12,715 corrections on drawings are identified.

• Journal of the Korean Society of Combustion
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• v.7 no.1
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• pp.1-7
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• 2002

Experiments have been performed to investigate the structure of axisymmetric hydrogen diffusion flame in a supersonic coflow air. The characteristics and structure of supersonic flames are compared with those of subsonic flames as the velocity of coflow air increases from subsonic to supersonic velocity of Mach 1.8. Also, the subsonic and supersonic flow fields are analyzed numerically for the non-reacting conditions and the possible flame contours indicated by fuel mass fraction are compared with the measured OH radical distributions. It is found that the flame structure indicates more like a partially premixed flame as the coflow air velocity is increased from subsonic to supersonic regimes; strong reaction zone indicated by intense OH signal is found at the center, which is different from subsonic flame cases. And it is shown that the fuel jet passes along the recirculation zones behind the bluff-body fuel nozzle resulting in relatively long mixing time. This is believed to be the reason of the partially premixed flame characteristics found in the present supersonic flames.

• YAKHAK HOEJI
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• v.51 no.3
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• pp.206-213
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• 2007

Recently estimating the uncertainty of an analytical result has become an essential part of quantitative analysis. This study describes the uncertainty of the measurement for the determination of methamphetamine and its major metabolite amphetamine in human hair, The method consists of washing, drying, weighing, incubation and extraction with methanolic HCI solution, clean-up, trifluoroacetyl derivatization, and qualification/quantification of residues by gas chromatography/mass spectrometry (GC/MS). Traceability of measurement was established through traceable standards and calibrated volumetric equipment and measuring instruments. Measurement uncertainty associated with each analyte in real samples was estimated using quality control (QC) data. The main source of combined standard uncertainty comprised two components, which are uncertainties associated with calibration linearity and variations in QC, while those associated with preparation of analytical standards and sample weighing were not so important considering the degree of contribution. Relative combined standard uncertainties associated with the described method ranged for individual analytes from 4.99 to5.03%.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.565-568
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• 2006

This study evaluates the physical mchanical properties, durability of porous concrete for pavement according to content of polymer and steel fiber to elicit the presentation of data and the way to enhance its function for the practical field application of porous concrete as a material of pavement. The results of the test indicate that in every condition, the void ratio and the coefficient of water permeability of porous concrete for pavement satisfy both the domestic standards and proposition values. Among the properties of strength, the compressive strength satisfies the standards in the specification of Korea National Housing Corporation as for every factor of mixture but in the case of the flexural strength, more than 0.6Vol.% of steel fiber satisfied the Japan Concrete Institute proposition values. The case when 0.6Vol.% of steel fiber and 10Wt.% of polymer are used at the same time shows that the loss rate of mass by Cantabro test became 36.7% better and freeze-thaw resistance became 33% better.

• Journal of Conservation Science
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• v.35 no.1
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• pp.51-60
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• 2019

This paper provides quantitative data that describes the evolution of the air quality in the Whale and Sea Museum, located in the Iwate prefecture, collected after the 2011 Great East Japan Earthquake and tsunami. The museum was damaged significantly by the disaster, and restoration works continued for over six years. The air quality in the temporary storage facility and museum was monitored during the rehabilitation process. Evaluation of air quality is carried out by gas chromatography- mass spectrometry, ion chromatography and high-performance liquid chromatography. The results showed that the characteristics of the chemical components differed depending on the measurement locations inside the building. The museum atmosphere tended to be alkaline as the airtightness increased because of the maintenance works at the entrance. It was also determined that it was necessary to study the intake/exhaust routes and to clean them according to the contamination degree. In Japan, there are recommended museum air quality standards for acetic acid, formic acid, alkali, and aldehydes. The results indicated that these standards should not be used as a reference for damaged museums. Furthermore, at the temporary storage facilities for to store the collections during the rehabilitation of the museum, solvents such as ethyl benzene, toluene, and xylene are initially abundant, although they can be reduced by ventilation, while other components such as 2E1H was confirmed in this case are likely to remain.