• 한국연소학회:학술대회논문집
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• 2000.12a
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• pp.168-174
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• 2000

A diode laser sensor system based on absorption spectroscopy techniques has been developed to measure $CO_2$ concentration and temperature non-intrusively in high temperature combustion environments using a 2.0 ${\mu}m$ DFB(Distributed Feedback) laser. Two optics was fabricated in pig-tail fashion and all optical components were implemented in a single box. The evolution of measurement sensitivity was done using test cell by changing sweep frequency and $CO_2$ concentration. Gas temperature was determined from the ratio of integrated line strengths. Species concentration was determined from the integrated line intensity and the measured temperature. The result show that the system has 2% error in wide operation frequency range and accuracy of $CO_2$ concentration was about 3%. The system was applied to measure temperature and concentration in the combustion region of a premixed $CH_4$ +air triangular flame. The measurement results of gas temperature agreed well with thermocouple results. Many considerations were taken into account to reduce optical noise, etalon effect, beam steering and base line matching problem. The evaluations results and actual combustion measurement demonstrate the practical and applicability for in-situ and real time combustion monitoring in a practical system.

• Corrosion Science and Technology
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• v.8 no.1
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• pp.21-26
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• 2009

The influence of $H_2S$ on the corrosion of iron and the corrosion prevention mechanism of an inhibitor was investigated with a differential capacitance measurement and a weight loss measurement method. The results show that $H_2S$ accelerates both the anodic iron dissolution and the cathodic hydrogen evolution in most cases. However, $H_2S$ acts as an inhibitor of the corrosion of iron under certain special conditions. An EIS method is proposed to explain the ability of inhibitors.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.2
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• pp.251-255
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• 2015

Thermal deformation, such as bending and twisting, occurs among the polymer parts of air-conditioner indoor units because of repetitive temperature change during heating operation. In this study, a numerical method employing finite-element analysis to efficiently simulate the thermal deformation of an assembly is proposed. Firstly, the displacement of an actual assembly produced by thermal deformation was measured using a 3D optical measurement system. The measurement results indicated a general downward sag of the assembly, and the maximum displacement value was approximately 1 mm. The temperature distribution was measured using a thermographic camera, and the results were used as initial-temperature boundary conditions to perform temperature-displacement analysis. The simulation results agreed well with the measured data. To reduce the thermal deformation, the stiffness increased 100%. As the results, the maximum displacement decreased by approximately 5.4% and the twisting deformation of the holder improved significantly.

• Journal of Mechanical Science and Technology
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• v.17 no.12
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• pp.2099-2106
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• 2003

In this paper, a novel fast response NDIR analyzer (FRNDIR), which uses an electrically pulsed semiconductor emitter and dual type PbSe detector for the PPM-level detection of carbon dioxide (CO$_2$) at a wavelength of 4.28 $\mu\textrm{m}$, is described. Modulation of conventional NDIR energy typically occurs at 1 to 20 Hz. To achieve real time high-speed measurement, the new analyzer employs a semiconductor light emitter that can be modulated by electrical chopping. Updated measurements are obtained every one millisecond. The detector has two independent lead selenide (PbSe) with IR band pass filters. Both the emitter accuracy and the detector sensitivity are increased by thermoelectric cooling of up to -20 degrees C in all semiconductor devices. Here we report the use of semiconductor devices to achieve improved performance such that these devices have potential application to CO$_2$ gas measurement and, in particular, the measurement of fast response CO$_2$ concentration at millisecond level.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.888-894
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• 2016

In this paper, we describe a method for precisely measuring the abrasion of the railway using an image processing technique. To calculate the wear of the rails, we provided a method for accurately matching the standard rail profile data and the profile data acquired by the rail inspection vehicle. After the lens distortion correction and the perspective transformation of the measured profile data, we used ICP Algorithm for accurate profile data matching with the reference profile extracted from the standard rail drawing. We constructed the prototype of the Rail Profile Measurement System for High-speed Railway and the experimental result on the three type of the standard rail used in Korea showed the excellent profile matching accuracy within 0.1mm.

• Korean Journal of Optics and Photonics
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• v.20 no.2
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• pp.134-140
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• 2009

In this study, the influence of surface roughness on light scattering from Au pads on a PCB surface was investigated. Angular distributions of light scattered from Au pads with different surface roughness were measured for several incident angles. Diffusely-scattered light could be separated by using the fact that the amount of specularly-scattered light was directly related to surface roughness. The separated diffuse term was curve-fitted with a physics-based model, and then the related scattering parameters were extracted and compared with measured parameters.

• Proceedings of the KWS Conference
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• 2003.11a
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• pp.39-41
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• 2003

• Proceedings of the Korean Society of Laser Processing Conference
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• 2001.11a
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• pp.55-59
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• 2001

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1675-1682
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• 2013

To resolve the Global Warming problem, it have to reduce $CO_2$ emission. Korea need to do actively more the effort to reduce the emission because $CO_2$ emission per person is top level in the world. It is performing variously. However, we should recognize the $CO_2$ emission attribute to decrease $CO_2$. Analyzing $CO_2$ emission of the construction equipment is important in this aspect. Present, the most popular $CO_2$ emission measuring method is the way using fuel consumption and emission factor. But this method have the problem of reliability because can't reflect the factor being out of proportion at fuel consumption. This study analyzed the reason of difference and compared to the emission factor method after calculate $CO_2$ emission in direct measurement method.

• Journal of Soil and Groundwater Environment
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• v.20 no.4
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• pp.73-82
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• 2015

Despite significant effects on macroscopic migration and distribution of CO₂ injected during geological sequestration, only limited information is available on wettability in microscopic scCO₂-brine-mineral systems due to difficulties in pore-scale observation. In this study, a micromodel had been developed to improve our understanding of how scCO₂ flooding and residual characteristics of porewater are affected by the wettability in scCO₂-water-glass bead systems. The micromodel (a transparent pore structure made of glass beads and glass plates) in a pressurized chamber provided the opportunity to visualize scCO₂ spreading and porewater displacement. CO₂ flooding followed by fingering migration and dewatering followed by formation of residual water were observed through an imaging system. Measurement of contact angles of residual porewater in micromodels were conducted to estimate wettability in a scCO₂-water-glass bead system. The measurement revealed that the brine-3M NaCl solution-is a wetting fluid and the surface of glass beads is water-wet. It is also found that the contact angle at equilibrium decreases as the pressure decreases, whereas it increases as the salinity increases. Such changes in wettability may significantly affect the patterns of scCO₂ migration and porewater residence during the process of CO₂ injection into a saline aquifer at high pressures.