• Title/Summary/Keyword: chemical measurement

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측정불확도의 개념과 GUM (The Concept of Measurement Uncertainty and the GUM)

  • 이종화
    • 대한화학회지
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    • 제67권5호
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    • pp.319-332
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    • 2023
  • Guide to the Expression of Uncertainty in Measurement (GUM)가 발간된 1993년부터 측정불확도는 측정학의 핵심 개념으로 여겨져 왔으며 적절한 불확도 평가의 중요성은 꾸준히 높아지고 있다. 하지만 측정불확도의 개념과 GUM에 대해 충분히 정확하고 상세하게 설명하는 국문 자료는 거의 없는 실정이다. 본 총설은 측정불확도 개념과 GUM의 수학적, 역사적, 철학적 배경을 상세하게 설명하며 화학 분야 불확도 평가의 특수성을 논한다.

침적식 온라인 굴절계를 이용한 알코올 농도의 측정 (Concentration Measurement of Alcohol Solution Using Immersion-Type On-Line Refractometer)

  • 정옥진;김영한
    • 제어로봇시스템학회논문지
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    • 제9권6호
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    • pp.473-477
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    • 2003
  • An immersion-type on-line refractometer useful for the in-situ measurement of chemical composition and temperature is developed, and its performance is examined by applying the refractometer to known alcohol solution having concentrations between 0 vol. % and 25 vol. %. Because refractive index and temperature are measured simultaneously, it is possible to compensate the effect of temperature for fast and direct measurement. The outcome of composition measurement for the different concentrations of alcohol solution indicates that the device is suitable for the chemical composition measurement by yielding stable and reproducible reading.

Static measurement of yield stress using a cylindrical penetrometer

  • Uhlherr, P.H.T.;Guo, J.;Fang, T.N.;Tiu, C.
    • Korea-Australia Rheology Journal
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    • 제14권1호
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    • pp.17-23
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    • 2002
  • A novel and simple method using a cylindrical penetrometer is being developed for the measurement of yield stress. The principle of this technique is based on the measurement of the static equilibrium of a falling penetrometer in a yield stress fluid. The yield stress is simply determined by a balance of forces acting on the penetrometer. The yield stress of Carbopol gels and $TiO_2$ suspensions has been measured using this method. The results are in reasonable agreement with the values from conventional methods. The effects of the dimensions and weight of the penetrometer have been examined. The long-term behaviour was also observed. No measurable creep was seen and equilibrium was found to be very quickly established. The cylindrical penetrometer technique promises to be a simple, quick and reliable static method for the measurement of yield stress.

수정진동자 미량저울을 이용한 공기 중 먼지의 온라인 측정 (On-Line Measurement of Solid Particles in Air Using a Quartz Crystal Microbalance)

  • 최광재;김영한;장상목
    • 센서학회지
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    • 제8권4호
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    • pp.314-319
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    • 1999
  • 공기중의 먼지를 수정진동자를 이용한 미량저울을 써서 측정하는 실험을 수행하였다. 측정장치를 컴퓨터에 연결하여 여러 개의 센서를 활용함으로서 동시측정이 가능한 장치를 만들었다. 본 연구에서는 실험장치의 구체적인 사항을 자세히 설명하여 비슷한 장치를 이용한 다른 유사한 실험에 활용하는 데 도움을 주고자 하였다. 연구의 결과 본 측정시스템이 공기 중 먼지농도의 연속측정에 적합함을 알 수 있었다.

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An Approach for the Uncertainty Evaluation of the Overall Result from Replications of Measurement: Separately Combining Individual Uncertainty Components According to their 'systematic' and 'random' Effects

  • Kim, In Jung;Kim, Byungjoo;Hwang, Euijin
    • Bulletin of the Korean Chemical Society
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    • 제35권4호
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    • pp.1057-1060
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    • 2014
  • In our previous articles, an approach has been proposed for the evaluation of the uncertainty of overall result from multiple measurements. In the approach, uncertainty sources were classified into two groups: the first including those giving same 'systematic' effect on each individual measurement and the second including the others giving 'random' effect on each individual measurement and causing a variation among individual measurement results. The arithmetic mean of the replicated measurements is usually assigned as the value for the overall result. Uncertainty of the overall result is determined by separately evaluating and combining an overall uncertainty from sources of the 'systematic' effect and another overall uncertainty from sources of the 'random' effect. This conceptual approach has been widely adopted in chemical metrology society. In this study, further logical proof with more detailed mathematical expressions is provided on the approach.

Effect of D-(+)-Glucose on the Stability of Polyvinyl Alcohol Fricke Hydrogel Three-Dimensional Dosimeter for Radiotherapy

  • Yang, Yuejiao;Chen, Jie;Yang, Liming;Chen, Bin;Sheng, Zhenmei;Luo, Wenyun;Sui, Guoping;Lu, Xun;Chen, Jianxin
    • Nuclear Engineering and Technology
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    • 제48권3호
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    • pp.608-612
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    • 2016
  • D-(+)-glucose (Glc) was added to the original Fricke polyvinyl alcohol-glutaraldehyde-xylenol orange (FPGX) hydrogel dosimeter system to make a more stable FPGX hydrogel three-dimensional dosimeter in this paper. Polyvinyl alcohol was used as a substrate, which was combined with Fricke solution. Various concentrations of Glc were tested with linear relevant fitting for optimal hydrogel production conditions. The effects of various formulations on the stability and sensitivity of dosimeters were evaluated. The results indicated that D-(+)-Glc, as a free radical scavenger, had a great effect on stabilizing the dose response related to absorbency and reducing the auto-oxidization of ferrous ions. A careful doping with Glc could slow down the color change of the dosimeter before and after radiation without any effect on the sensitivity of the dosimeter.

Numerical and Experimental Analyses of a Hot-Wire Gas Flowmeter

  • Kim, Byoung-Chul;Joung, Ok-Jin;Kim, Young-Han
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2003년도 ICCAS
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    • pp.1201-1206
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    • 2003
  • A measurement device for gas flow rate using hot-wire module is developed for the utilization in low-accuracy industrial applications. The module has three wires of measuring and heating, and a bridge circuit is installed to detect electric current through the wire in the module. An amplification of the signal and conversion to digital output are conducted for the online measurement with a personal computer. In addition, temperature distribution in the module is numerically analyzed to examine the measured outcome from the module experiment. The flow rate of air and carbon dioxide gas is separately measured for the performance examination of the device. The experimental relation of measurement and flow agrees with the prediction from the numerical analysis. The outcome of the performance test indicates that the accuracy and reproducibility of the module is satisfactory for the purpose of industrial applications.

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Performance Evaluation of Hazardous Substances using Measurement Vehicle of Field Mode through Emergency Response of Chemical Incidents

  • Lee, Yeon-Hee;Hwang, Seung-Ryul;Kim, Jae-Young;Kim, Kyun;Kwak, Ji Hyun;Kim, Min Sun;Park, Joong Don;Jeon, Junho;Kim, Ki Joon;Lee, Jin Hwan
    • 한국환경농학회지
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    • 제34권4호
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    • pp.294-302
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    • 2015
  • BACKGROUND: Chemical accidents have increased owing to chemical usage, human error and technical failures during the last decades. Many countries have organized supervisory authorities in charge of enforcing related rules and regulations to prevent chemical accidents. A very important part in chemical accidents has been coping with comprehensive first aid tool. Therefore, the present research has provided information with the initial applications concern to the rapid analysis of hazardous material using instruments in vehicle of field mode after chemical accidents. METHODS AND RESULTS: Mobile measurement vehicle was manufactured to obtain information regarding field assessments of chemical accidents. This vehicle was equipped with four instruments including gas chromatography with mass spectrometry (GC/MS), Fourier Transform Infrared Spectroscopy (FT-IR), Ion Chromatography (IC), and UV/Vis spectrometer (UV) to analyses of accident preparedness substances, volatile compounds, and organic gases. Moreover, this work was the first examined the evaluation of applicability for analysis instruments using 20 chemicals in various accident preparedness substances (GC/MS; 6 chemicals, FT-IR; 2 chemicals, IC; 11 chemicals, and UV; 1 chemical) and their calibration curves were obtained with high linearity ( r 2 > 0.991). Our results were observed the advantage of the high chromatographic peak capacity, fast analysis, and good sensitivity as well as resolution. CONCLUSION: When chemical accidents are occurred, the posted measurement vehicle may be utilized as tool an effective for qualitative and quantitative information in the scene of an accident owing to the rapid analysis of hazardous material.