• 반도체디스플레이기술학회지
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• 제7권2호
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• pp.55-58
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• 2008

The objective of the research is to design, manufacture and test a Mass Flow Controller(MFC) capable of measuring compressible fluid flows based on a "bucket and stop-watch"method. The basic principle is the measurement of time, where the time taken to fill and empty a bucket of known volume is measured. This method of flow measurement is a new concept when compared to a commercilized current mass flow controller. For the flow meter to be able to compete with established designs it not only must be comparable in cost and robustness, it must be very accurate and reliable as well. This device should be able to handle fluid flows in the range of 0.1ml/min to 10ml/min within an accuracy of ${\pm}$1%. A possible application for a device such as this is in electronics industry where arsenic gas is used in the production of silicon chips.

• 한국입자에어로졸학회지
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• 제14권2호
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• pp.35-40
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• 2018

Vertical particle size distribution, total particle concentration, wind velocity, temperature and humidity measurement was performed with a drone. The drone was equipped with a wind sensor, house-made optical particle count(Hy-OPC), condensation particle counter(Hy-CPC), GPS, Temperature, Relative Humidity, Pressure and communication system. Base on the wind velocity and the particle size vertical distribution measurement with drone, the particle mass flux was calculated. The vertical particle distribution showed that the particle number concentration was very strongly correlated with the relative humidity.

• Bulletin of the Korean Chemical Society
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• 제20권8호
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• pp.910-916
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• 1999

A current interest in chemistry concerns traceability of analytical measurements to the International System of Units (SI) and the proper estimation of their uncertainties in accordance with the internationally agreed guide provided by the International Organization for Standardization (ISO). Isotope dilution mass spectrometry (IDMS) is regarded as a primary method, which make the measurement results traceable to SI units without significant empirical correction factors. Our laboratory, as the national standards institute of Korea, participated in an intercomparison of environmental analysis, pp'-DDE in corn oil, which was organized by the CCQM under supervision of the CIPM to test feasibility of IDMS as a primary method for the trace analysis of organic compounds. In this report, we provide basic equations used for the calculation of the concentration of the analyte in a sample and a precise description of the processes for the evaluation of the uncertainties of the measurement results. Also, we report the experimental conditions adopted to improve the accuracy of the IDMS measurement. The principles contained in ？？Guide to the Expression of Uncertainty in Measurement'' provided by ISO are followed for the uncertainty evaluation.

• 대한기계학회논문집B
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• 제30권6호
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• pp.497-504
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• 2006

A Coriolis mass flowmeter(CMF), which has U-Shaped unique measurins tube was developed fo. direct mass flow measurement. In order to convert the time difference between two measuring tubes motion into mass flowrate and flow quantity, a signal processing circuit, as a part of CMF, was also developed. The CMF was designed as the 15 mm nominal diameter of pipe connection and the 8 mm stainless steel(sus 316) pipe was used for measuring tube. To maximize the flow signal(time difference) from the measuring tubes, the natural frequency of measuring tube was adjusted as 220 Hz, which is same as the frequency of exciter. The maximum displacement at the end of the measuring tube was measured as 0.05 mm and the maximum time difference between two measuring tubes was observed as $20{\mu}s$, which was proper for discrimination and measuring range of CMF. The developed CMF was tested against the gravimetric flowmeter calibrator in the range of 3 kg/min and 30 kg/min. The results showed that the CMF has good linearity and repeatability in the tested flow range. Large size of CMF base on the current study experience will be developed.

• 한국분무공학회지
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• 제7권3호
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• pp.24-30
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• 2002

In the analysis of the mass distribution and SMD(Sauter Mean Diameter), planar laser imaging technique is a convenient and useful one when compared to the mechanical pattemator or PDPA (Phase Doppler Particle Analyzer). But recorded signals at cameras and intensity of laser are distorted by attenuation. Using experimental datum and assumptions, we study measurement errors due to attenuation in plannar image technique.

• 대한통합의학회지
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• 제11권2호
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• pp.129-140
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• 2023

Purpose : This study was conducted to investigate and analyze the physical health of older Koreans with sarcopenia and locomotive syndrome and identify the related factors. Methods : In this study, the sarcopenia and locomotive syndrome evaluations were applied to 210 elderly people, and the sarcopenia group was 36, the locomotive syndrome group was 164, and the normal group was 10. After group selection, a physical health status survey was conducted. The physical health status was assessed via body composition analysis, physical characteristics survey including measurement of waist and calf circumference, investigation of diseases currently being diagnosed by a doctor, and frailty measurements. The collected data were statistically analyzed using one-way ANOVA, the Kruskal-Wallis test, and the Chi-square test. Results : There were significant differences between groups in all elements of physical characteristics including body mass index, waist circumference, and calf circumference. Among them, a consistent result was found that the normal group had the largest amount of muscle mass and the sarcopenia group had the least amount of muscle mass in the factors related to muscle mass. However, the factors relating to fat mass and obesity also showed significant differences between the groups, but the results were not consistent. Considering the group differences in current diseases, a significant difference was only detected for osteoporosis among 12 diseases. Moreover, those in the sarcopenia group had the highest rate of osteoporosis. And there was no significant difference between the groups in the total score of the frailty measurement, but there was a significant difference between the groups in the frailty measurement levels. Conclusion : This study on physical health status confirmed that muscle mass-related factors, osteoporosis, and frailty levels were significantly related to sarcopenia and locomotive syndrome.

• Tuberculosis and Respiratory Diseases
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• 제86권4호
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• pp.272-283
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• 2023

Background: In patients with chronic obstructive pulmonary disease (COPD), decreased muscle mass is a frequently encountered comorbidity in clinical practice. However, the evaluation of muscle mass in patients with COPD in real-world practice is rare. Methods: We retrospectively reviewed the electronic medical records of all patients with COPD who underwent bioelectrical impedance analysis at least once between January 2011 and December 2021 in three hospitals. Then, we analyzed the performance rate of muscle mass measurement in the patients and the correlation between muscle mass, clinical parameters, and COPD prognosis. Results: Among the 24,502 patients with COPD, only 270 (1.1%) underwent muscle mass measurements. The total skeletal muscle mass index was significantly correlated with albumin, alanine transaminase, and creatinine to cystatin C ratio in patients with COPD (r=0.1614, p=0.011; r=0.2112, p=0.001; and r=0.3671, p=0.001, respectively). Acute exacerbation of COPD (AE COPD) was significantly correlated with muscle mass, especially the truncal skeletal muscle mass index (TSMI) in males (r=-0.196, p=0.007). In the multivariate analysis, TSMI and cystatin C were significant risk factors for AE COPD (hazard ratio, 0.200 [95% confidence interval, CI, 0.048 to 0.838] and 4.990 [95% CI, 1.070 to 23.278], respectively). Conclusion: Low muscle mass negatively affects the clinical outcomes in patients with COPD. Despite its clinical significance, muscle mass measurement is performed in a small proportion of patients with COPD. Therefore, protocols and guidelines for the screening of sarcopenia in patients with COPD should be established.

• Clinical and Experimental Pediatrics
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• 제48권7호
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• pp.696-700
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• 2005

목 적 : 소아 체지방 평가에 있어 여러 가지 방법 중 BIA를 이용한 체성분 분석은 비침습적이고, 경제적이며, 방사선 노출의 위험이 없이 검사가 용이해 반복 시행할 수 있다는 장점이 있는 반면 검사 결과의 정확성에 대해 확인해 볼 필요가 있다. 이에 BIA 및 이중 DEXA에 의한 측정치들을 비교하여 BIA의 타당성을 알아보고자 하였다. 방 법 : 2003년 7월에서 10월까지 4개월 동안 부산대학교병원 소아과 방문하였던 소아 100명(남아 58명, 여아 42명)을 연구대상으로 하여 연구 대상자들에 대하여 각각 신장, 체중, 피부두께를 측정하였으며, BIA 및 DEXA법을 이용하여 체성분(체지방량, 제지방량, 제지방률, 체수분량)을 분석하였다. 결 과 : BIA와 DEXA법을 통한 검사상 FBM, LBM, %BF의 상관관계는 남녀 모두에서 통계학적으로 의미있는 양의 상관관계를 보였으며, 통계학적으로 의미가 있었다(P<0.001). 특히 FBM에서 남녀 모두 상관 계수가 높았다. 결 론 : 소아 비만의 평가에 있어 BIA를 통한 체성분 분석은 장치가 간단하고 특별한 기술을 필요로 하지 않으며, 비침습적이면서 경제적일 뿐 아니라 측정치가 객관적이고 정확한 것으로 분석되었다.

• 분석과학
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• 제8권4호
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• pp.849-854
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• 1995

A series of biologically active phosphopeptides were synthesized and their behavior in tandem mass spectrometry have been investigated. The structure identifications of other unusual peptides such as sulphated, glycosylated, lipoidal, and backbone modified peptides have been carried out. For all tested peptides, the structural modification could be determined directly by measurement of the absolute molecular weight in combination with collision-induced-dissociation in tandem mass spectrometry.

• 한국진공학회지
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• 제2권3호
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• pp.314-318
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• 1993

Quadrupole mass spectrometer는 부분압 측정 및 잔류기체 분석에 널리 이용되고 있는 장비이다. CO, H2, Ar이 혼합되어 존재할 때 quadrupole mass spectrometer의 감도를 10-4∼10-8torr영역에서 측정하고 단일기체로 존재할 때의 감도와 비교하였다. 그 결과 일정한 부분압을 유지하고 있는 경우라도, 주위 분위기 기체 종류와 부위기 기체 압력에 따라 감도 별화가 심한 것을 알 수 있었다. 따라서 QMS를 부분압 측정이나 조성분석에 이용하기 위해서는 이에 대한 특성조사가 반드시 필요하다.