• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.224-227
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• 2011

In order to determine the enthalpy profile in the high temperature transpiration cooling test facility for the air-breating engine compartments, theoretical calculation and measurement for the flow of the test section are performed. The mass averaged enthalpy value determined by the heat balance and sonic throat methods is 10 MJ/kg. The centerline enthalpy value measured using the slug type copper calorimeter is 15 MJ/kg. Typically, the ratio of centerline and mass averaged enthalpy should be varies from 1.4 to 4. This facility has lower bound of enthalpy profile. It will be effective in testing of high temperature transpiration cooling.

• Atmosphere
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• v.29 no.5
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• pp.511-523
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• 2019

A new Korean Meteorological Administration (KMA) airborne measurement platform has been established for regular observations for scientific purpose over South Korea since late 2017. CRDS G-2401m analyzer mounted on the King Air 350HW was used to continuous measurement of CO₂, CH₄ and CO mole fraction. The total uncertainty of measurements was estimated to be 0.07 ppm for CO₂, 0.5 ppb for CH₄, and 4.2 ppb for CO by combination of instrument precision, repeatability test simulated in-flight condition and water vapor correction uncertainty. The airborne vertical profile measurements were performed at a regional Global Atmosphere Watch (GAW) Anmyeon-do (AMY) station that belongs to the Total Carbon Column Observing Network (TCCON) and provides concurrent observations to the Greenhouse Gases Observing Satellite (GOSAT) overpasses. The vertical profile of CO₂ shows clear altitude gradient, while the CH₄ shows non-homogenous pattern in the free troposphere over Anmyeon-do. Vertically averaged CO₂ at the altitude between 1.5 and 8.0km are lower than AMY surface background value about 7 ppm but higher than that observed in free troposphere of western pacific region about 4 ppm, respectively. CH₄ shows lower level than those from ground GAW stations, comparable with flask airborne data that was taken in the western pacific region. Furthermore, this study shows that the combination of CH₄ distribution in free troposphere and trajectory analysis, taking account of convective mixing, is a useful tool in investigating CH₄ transport processes from tropical region to Korean region in winter season.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.4
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• pp.154-160
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• 2005

We have investigated thermal properties showed by changing the content of carbon black which is the component parts of semiconductive shield in underground power transmission cable. Specimens were made of sheet with the nine of those for measurement. Density of specimens was measured by density meter, and then stress-strain of specimens was measured by TENSOMETER 2000. A speed of measurement was 200[mm/min], ranges of stress and strain were 400(Kgf/$cm^2$) and 600[$\%$]. In addition, tests of stress-strain were progressed by aging specimens at air oven. Finally surface profile was shown in order to looking for protrusion of specimens by using smoothness tester. Density was highly measured according to increasing the content of carbon black from this experimental result, and stress was decreased, while strain was increased according to increasing the content of carbon black. And stress-strain were decreased some after aging because of oxidation reaction of chemical defect. Lastly surface of specimens smoothed generally.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.1
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• pp.37-44
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• 2012

This paper describes energy loss in a pipe line of refuse collecting system. Analysis of energy loss in a pipe line is the decisive factor in a design of refuse collecting system. Using the results of energy loss analysis, we can determine the power of turbo-blower. The flow characteristics of the pipe line with refuse bags were analyzed by three-dimensional CFD. The refuse bag is modeled by using the shape obtained from profile measurement. Friction factors were calculated with changing the refuse bag size, mixing ratio and Reynolds number. And drag coefficients were calculated using the CFD results. From the results we can calculate energy loss in a pipe line of refuse collecting system and predict the capacity of turbo-blower.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2356-2361
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• 2003

Proteome research in the medical field is expected to accelerate the understanding of disease mechanism, and to create new diagnostic concept. For protein profiling, this paper proposes a new methodology named CPDIB (Crude Protein Direct Blotting). In the CPDIB procedure, crude protein sample is directly immobilized on a membrane and the expression of protein molecules in the sample are analyzed quantitatively by using a special device called ImmobiChip, where the membrane is used as a field of the immune reaction. The over-all structure of the ImmobiChip is based on the conventional Slot blot device. Mechanical improvement in the air-tightness of the case holding the membrane realizes the direct blotting and results in high performance of stability in the immune reaction. In the measurement of multiple proteins, a dispensing robot is used for increasing the efficiency of handling of liquid. Cooperation of the dispensing robot with the ImmobiChip for immobilizing proteins realizes automated and stable performance of the CPDIB procedure. This paper shows the evaluation of the air-tightness of the ImmobiChip, the ability of analyzing proteins using the CPDIB procedure and the performance of the automated equipment.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.1
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• pp.73-77
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• 1998

In this study, a total of 10 volatile organic compounds (VOCs) including BTEX were determined in the inside and outside of a highway thnnel in order to evaluate the emission profile of automobile exhaust with respect to the concentrations, relative ratio and correlation coefficient of target analytes. In addition to VOCs, CO $CO_2 and NO_2$ were measured simultaneously. The results of this study indicated that the most abundant compound was toluene followed by benzene and m+p-xylenes, and the correlation coefficients between VOCs except styrene were higher than 0.96. The concentration ratio of toluene, ethylbenzene, xylenes with respect to benzene measured in the inside of tunnel was 1.5, 0.13, 0.74, respectively. Such ratios were found to be very similar to those measured in tunnels in the USA.

• Journal of the Optical Society of Korea
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• v.7 no.2
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• pp.79-83
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• 2003

In this paper, we describe the fabrication process of a photonic crystal fiber and present the measured optical properties of the photonic crystal fiber. The fabrication of the photonic crystal fiber involves stacking, jacketing, collapsing, and drawing using a conventional drawing tower The photonic crystal fiber drawing needs higher tension to maintain the uniform air hole structure. Thus, the temperature of the photonic crystal fiber drawing is lowered by a few hundred degrees Celsius than for the case of conventional optical fiber drawing. The optical properties of the fabricated photonic crystal fiber such as mode profile, optical loss, transmission spectrum, bending loss, and polarization dependent loss are measured.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.3
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• pp.27-32
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• 2008

This paper describes a contact atomic force microscope (AFM) that can be used for high-speed precision measurements of microstructured surfaces. The AFM is composed of an air-bearing X stage, an air-bearing spindle with the axis of rotation in the Z direction, and an AFM probe unit. The traversing distance and maximum speed of the X stage are 300 mm and 400 mm/s, respectively. The spindle has the ability to hold a sample in a vacuum chuck with a maximum diameter of 130 mm and has a maximum rotation speed of 300 rpm. The bandwidth of the AFM probe unit in an open loop control circuit is more than 40 kHz. To achieve precision measurements of microstructured surfaces with slopes, a scanning strategy combining constant height measurements with a slope compensation technique is proposed. In this scanning strategy, the Z direction PZT actuator of the AFM probe unit is employed to compensate for the slope of the sample surface while the microstructures are scanned by the AFM probe at a constant height. The precision of such a scanning strategy is demonstrated by obtaining profile measurements of a microstructure surface at a series of scanning speeds ranging from 0.1 to 20.0 mm/s.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.599-603
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• 2003

This paper present an error compensation system and On-Machine Measurement(OMM) system for improving the machining accuracy of ultra-precision lathe. The Fast-Tool-Servo(FTS) driven by a piezoelectric actuator is applied for error compensation system. The controller is implemented on the 32bit DSP for feedback control of piezoelectric actuator. The control system is designed to compensates three kinds of machining errors such as the straightness error of X-axis slide, the thermal growth error of the spindle. and the squareness between spindle and X-axis slide. OMM is preposed to measure the finished profile of workpiece on the machine-tool using capacitive sensor with highly accurate ruby tip probe guided by air bearing. The data acquisition system is linked to the CNC controller to get the position of each axis in real-time. Through the experiments, it is founded that the thermal growth of spindle and tile squareness error between spindle and X-axis slide influenced to machining error more than straightness error of X-axis slide in small travel length. These errors were simulated as a sinusoidal signal which has very low frequency and the FTS could compensate the signal less than 30 m. The implemented OMM system has been tested by measuring flat surface of 50 mm diameter and shows measurement error less than 400 mm

• Korean Journal of Remote Sensing
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• v.19 no.3
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• pp.217-221
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• 2003

The Measurement of Pollution in the Troposphere (MOPITT) instrument is an eight-channel gas correlation radiometer that launched on the Earth Observing System (EOS) Terra spacecraft in 1999. Its main objectives are to measure carbon monoxide (CO) and methane (CH4) concentrations in the troposphere. This study analyzes tropospheric carbon monoxide distributions using MOPITT data and compare with ozone distributions in Northeast Asia. In general, seasonal CO variations are characterized by a peak in spring and decrease in summer. Also, this study revealed that the seasonal cycles of CO are maximum in spring and minimum in summer with average concentrations ranging from 118ppbv to 170ppbv. The monthly average of CO shows a similar profile to those of O3. This fact clearly indicates that the high concentration of CO in spring is caused by two possible causes: the photochemical CO production in the troposphere, or the transport of the CO in the northeast Asia. The CO and $O_3$ seasonal cycles in the Northeast Asia are influenced extensively by the seasonal exchange of the different types of air mass due to the Asian monsoon. The continental air masses contain high concentrations of $O_3$ and CO due to higher continental background concentrations and sometimes due to the contribution of regional pollution. In summer the transport pattern is reversed. The Pacific marine air masses prevail over Korea, so that the marine air masses bring low concentrations of CO and $O_3$, which tend to give the apparent minimum in summer.