• 터널과지하공간
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• 제8권2호
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• pp.139-145
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• 1998

The reliable estimation of the system parameters and the accurate prediction of the system behavior are important to design underground structures safely and economically. Especially, the elastic modulus and the in-situ stresses are very important parameters in predicting the behavior of the underground structure. Therefore, the back analysis using the field measurement data is developed to determine accurately the elastic modulus and the in-situ stresses of the underground structural system in this study. A back analysis using the combined finite and boundary element is developed. It can consider the far field boundary condition and is efficient in computation. In this study, a back analysis is performed to predict behaviors of underground structures for the real construction site. The comparison between the results of the back analysis with field measurement data and the obtained material properties from the field test shows good agreement for the real construction site.

• 한국광학회:학술대회논문집
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• 한국광학회 1998년도 제15회 광학 및 양자전자 학술발표회 논문집
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• pp.132-133
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• 1998

• Environmental Engineering Research
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• 제10권2호
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• pp.71-78
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• 2005

A series of column experiments was conducted to develop a monitoring system for in-situ and realtime measurement of ozone transport in unsaturated porous media using a fiber optic sensor. The calibration of the fiber optic transflection dip probe (FOTDP) system was successfully carried out at various ozone concentrations using a column with length of 30 cm and diameter of 5 cm packed with glass beads, which don't react with gaseous ozone. The breakthrough curves (BTCs) of ozone were obtained by converting the normalized intensity into ozone concentration. The FOTDP system worked well for in-situ monitoring of gas phase ozone at various water saturations and in presence of soil organic matter (SOM). However, the FOTDP system did not measure the ozone concentration at more than 70% water saturation.

• 공업화학
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• 제34권4호
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• pp.383-387
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• 2023

범용적으로 고진공 성막 장비에서 사용되는 quartz crystal microbalance (QCM)는 두꺼운 필름이 quartz 위에 성막되는 경우, 크리스탈 고유의 진동에 영향을 주어 사용이 어려워진다. 본 논문에서는 실시간 필름 증착 공정 중에 센서의 손상이 없는 광학적 계측 방식을 통해 필름의 성막 속도를 측정하는 방법을 연구하였다. 기체 이동 경로로 지나가는 페럴린 가스 중 다이머에 의한 레이저의 산란 정도를 측정하여, 페럴린 공정의 분해부 온도가 감소할수록 페럴린 가스 중 다이머의 비율이 증가하는 것을 성공적으로 확인하였다. 또한, 성막된 필름의 특성을 확인한 결과, 분해부 온도가 감소할수록 필름의 두께와 haze가 증가한 것을 확인할 수 있었다. 우리는 연구 결과를 통해 개발한 안정적인 실시간 성막 속도 계측 시스템을 이용함으로써, 진공 공정을 통해 성막하는 페럴린 필름의 정밀한 성막 속도 제어에 활용하고자 한다.

• 한국대기환경학회지
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• 제23권2호
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• pp.191-202
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• 2007

We developed an in-situ analyzer to understand the HONO levels in indoor environments. The in-situ measurement system utilizes a diffusion scrubber and luminol chemiluminescence to measure the HONO concentration with time resolution of 4-minute. Concentrations of NO, $NO_{2}$, and HONO were determined at an indoor air of an apartment for 9 days using the developed in-situ analyzer. Indoor HONO concentrations were highly elevated when a gas range was operated. Enhancements of the indoor NO, $NO_{2}$, and HONO concentrations during combustion indicate that the observed indoor HONO was formed by direct emission. In addition to the direct emission, the indoor HONO was partially generated from heterogeneous reactions of $NO_{2}$ on indoor surfaces, which was supported by strong relationships between peak NO, $NO_{2}$, and HONO concentrations, high HONO/$NO_{2}$ ratio and a weak correlation between NO and HONO concentrations. Additionally, three combustion experiments during the whole measurement period were performed to investigate the effects of unvented and vented gas burning on the HONO, NO, and $NO_{2}$ concentrations and their decay. The decay rate of the HONO concentration was significantly less than the NO and $NO_{2}$ decay rates for all the experiments, indicating that the lifetimes of trace nitrogen species in indoor environment varied in the order approximately HONO>$NO_{2}$>NO.

• 터널과지하공간
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• 제6권3호
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• pp.197-208
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• 1996

Due to the constraints in pre site-investigation for tunnel, it is essential to redesign the support structures suitable for rock mass conditions such as rock strength, ground water and discontinuity conditions for safe tunnel construction. For the selection of optimum support, it is very important to carry out the rock mass classification and in-situ measurement in tunnelling. In this paper, in a mountain tunnel designed by NATM in hard rock, the selectable system for optimum support has been studied. The tunnel is situated at Chun-an in Kyungbu highspeed railway line with 2 lanes over a length of 4, 020 m and a diameter of 15 m. The tunnel was constructed by drill & blasting method and long bench cut method, designed five types of standard support patterns according to rock mass conditions. In this tunnel, face mapping based on image processing of tunnel face and rock mass classification by RMR carried out for the quantitative evaluation of the characteristics of rock mass and compared with rock mass classes in design. Also, in-situ measurement of convergence and crown settlement conducted about 30 m interval, assessed the stability of tunnel from the analysis of monitoring data. Through the results of rock mass classification and in-situ measurement in several sections, the design of supports were modified for the safe and economic tunnelling.

• 대한기계학회논문집A
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• 제21권7호
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• pp.1156-1165
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• 1997

Complex modal testing is employed for the in-situ parameter identification of a four-axis active magnetic bearing system while the system is in operation. In the test, magnetic bearings are used as exciters as well as actuators for feedback control. The experimental results show that the directional frequency response function, which is properly defined in the complex domain, is a powerful tool for identification of bearing as well as modal parameters. It is also shown that the position and current stiffnesses can be accurately estimated using the relations between the measured forces, displacements, and currents.

• 한국소음진동공학회논문집
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• 제22권4호
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• pp.377-382
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• 2012

This paper presents a proof-of-concept study on the evaluation of torsional vibration isolation performance through in-situ output torque measurement by using a non-contacting magneto-elastic torque transducer installed in the vehicle driveline system. The de-trending processing is first conducted to extract the torsional vibration from the measured driveline output torque. In order to estimate the transmissibility, primary performance indicator of a vibration isolator, the magnitude of transmitted torsional vibration with different frequencies is compared. From the conservative estimation results, the torsional damper built in a lock-up clutch of a torque converter is identified to be a vibration isolator. The evaluation results show that the fluid damping by torque converter outperforms the vibration isolation function of a torsional damper, and the isolation performance needs to be enhanced.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.382-387
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• 2012

This paper presents a proof-of-concept study on the evaluation of torsional vibration isolation performance through in-situ output torque measurement by using a non-contacting magneto-elastic torque transducer installed in the vehicle driveline system. The de-trending processing is first conducted to extract the torsional vibration from the measured driveline output torque. In order to estimate the transmissibility, primary performance indicator of a vibration isolator, the magnitude of transmitted torsional vibration with different frequencies is compared. From the conservative estimation results, the torsional damper built in a lock-up clutch of a torque converter is identified to be a vibration isolator. The evaluation results show that the fluid damping by torque converter outperforms the vibration isolation function of a torsional damper, and the isolation performance needs to be enhanced.

• 한국자동차공학회논문집
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• 제20권4호
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• pp.68-75
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• 2012

This paper presents a study on the driveline output torque estimation using a discrete Kalman filter. The in-situ output shaft torque is first measured by a non-contacting magneto-elastic torque transducer. The linear state-space system equations are first derived and the discrete Kalman filter is designed based on the Kalman filter theory to recover the driveline output torque contaminated by random noises. In addition to using torque measurement, the estimation of the output torque using two angular velocities: the output and wheel, is also conducted. The experimental results show that the discrete Kalman filter can be effective for not only removing the random noise in output torque but also estimating the output torque without torque measurement.