• Progress in Medical Physics
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• v.16 no.3
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• pp.111-115
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• 2005

We have designed the multi channel detector for the quality assurance of clinical photon beams. The detector was composed of solid phantom inserted by six plane-parallel ionization chambers at different depth. The chamber as a mini plane parallel chamber was made of carbon coated microfilms. In this study the electrical characteristics of the six chambers in the solid phantom were evaluated using 6 MV photon beam. The leakage currents were less than 0.5 pA, reproducibility was less than 0.5$\%$, linearity was less than 0.5$\%$, and dose rate effect was less than 0.7$\%$. In addition the effect of dose variation from other chambers was estimated to maximum 0.8$\%$ approximately. The developed detector can be used for quality determination in output dosimetry or measurement of percentage depth dose approximately for clinical photon beam.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2001.11a
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• pp.211-215
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• 2001

실내나 의복내 열적쾌적성을 평가하기 위해서는 정밀하고, 안정성이 높으며 빠른 응답특성을 갖는 센서와 측정시스템이 필요하다. 더욱이 의복내의 온도를 측정하기 위해서는 소형, 경량으로 인체에 부착하기 쉬워야하며 측정기의 부착이 피험자에게 부담을 주어서는 안된다. 본 연구에서는 이러한 요구사항을 만족할 수 있으면서도 이동이 자유롭고 장시간 측정이 가능한 큰 Data 저장용량, 실시간 측정 기능, 손쉬운 온습도 변환장치등을 갖춘 의복내 및 실내 온습도 측정등의 다양한 분야에 활용이 가능한 온습도 측정기와 이에 필요한 센서를 개발하고 개발된 측정기의 선형특성을 평가하였다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.6
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• pp.77-83
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• 2015

This paper is a study of the functions required for the system to quantify the closest target weight by combining several random weights such as chips, snacks, fruits, and vegetables. The multi-head weigher is designed for high-performance applications requiring increased production rates and tight accuracy tolerances. This combination system has 12 heads considered in the form of a rectangular array of $2{\times}6$ or $3{\times}4$. Channel combination can usually occur between 1 and n, and the frequency was the highest with two or three combinations. Experimental result of a combination system for a total target weight was measured at the range from 100g to 500g by increments of 50g, and the average success rate was about 70%. The average elapsed time was about 1.7 seconds, which means it can be used for the packaging of agricultural products with a variety of items.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.1
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• pp.384-398
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• 1996

An improved multi-channel Impedance Void Meter (IVM) is developed to measure an area-averaged void fraction. It consists of a main sensor, a reference sensor and a signal processor. The sensor was designed to be flush-mounted to the inner wall of the test section to avoid the flow disturbances. Guard electrodes are used to obtain evenly distributed electrical field in a measuring volume. A reference sensor is also installed to eliminate the drift in void signal caused by the changes in electrical properties of working fluid. The signal processor with three channels is specially designed so as to minimize the inherent error due to the phase difference between channels. As an example of applications, the mean and fluctuating components of void fraction are measured for bubbly and slug flow regime, and it is shown that IVM has good dynamic resolution which is required to investigate the structural developments of bubbly flow and the propagation of void waves in a flow channel.