• Journal of Ocean Engineering and Technology
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• v.13 no.3B
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• pp.22-28
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• 1999

The purpose of this study is to investigate the NOx emission of turbulent diffusion flame formed in the after burner, which is located on the waste gas coming out from the test furnace. Three types of flame was tested and each of which was changed by adequate equivalence ratio. It is necessary to study more about NOx reduction effect in the after burner system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.174-177
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• 2001

The electron transport coefficients, the electron drift velocity W, the longitudinal diffusion coefficient $ND_L$ and $D_L/{\mu}$, in pure Xe were calculated over the wide E/N range from 0.01 to 500 Td at 1 Torr by two-term approximation of the Boltzmann equation for determination of electron collision cross sections set and for quantitative characteristic analysis of Xe molecular gas.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.182-185
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• 2001

The electron transport coefficients, the electron drift velocity W, the longitudinal diffusion coefficient $ND_L$ and $D_L/{\mu}$, in pure Ne were calculated over the wide E/N range from 0.01 to 300 Td at 1 Torr by two-term approximation of the Boltzmann equation for determination of electron collision cross sections set and for quantitative characteristic analysis of Ne molecular gas.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.164-167
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• 2001

The electron transport coefficients, the electron drift velocity W, the longitudinal diffusion coefficient $ND_L$ and $D_L/{\mu}$, in pure $CO_2$ were calculated over the wide E/N range from 0.01 to 500 Td at 1 Torr by two-term approximation of the Boltzmann equation for determination of electron collision cross sections set and for quantitative characteristic analysis of $CO_2$ molecular gas. And for propriety of two-term approximation of Boltzmann equation analysis, the calculated results compared with the electron transport coefficients measured by Nakamura.

• Journal of Welding and Joining
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• v.35 no.3
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• pp.52-61
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• 2017

Transient liquid phase (TLP) bonding is essential technology to repair micro-cracking on the airfoil of blades and vanes for gas turbines. Understanding of the characteristics of TLP bonding of the superalloys is necessary in the application of the technology for repairing these components. In this study, the focus was on investigating TLP bonding characteristics of ${\gamma}^{\prime}$ precipitation strengthened Ni based superalloy. TLP bonding was carried out with an amorphous filler metal in various bonding conditions, and the microstructural characterization was investigated through optical microscopy (OM) and electron probe micro-analysis (EPMA). The experimantal results explained clearly that bonding temperatures had critical effects on the TLP bonding behaviors, and that isothermal solidication of the joints made at higher temperatures than $1170^{\circ}C$ was controlled by Ti diffusion instead of B.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.1
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• pp.115-121
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• 2008

In this paper, a three-dimensional computational fluid dynamic model of a proton exchange membrane fuel cell(PEMFC) with serpentine flow channel is presented. A steady state, single phase and isothermal numerical model has been established to investigate the influence of the GDL (Gas Diffusion Layer) parameters. The GDL is made of a porous material such as carbon cloth, carbon paper or metal wire mesh. For the simplicity, the GDL is modeled as a block of material having numerous pathways through which gaseous reactants and liquid water can pass. The porosity, permeability and thickness of the GDL, which are employed in the model parameters significantly affect the PEMFC performance at the high current region.

• Journal of the Korean Society of Safety
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• v.24 no.1
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• pp.21-25
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• 2009

Extinguishing limits of laminar ethylene/oxygen flames in both normal and inverse co-flow jet burner have been determined experimentally and computationally. An inert gas($N_2$, Ar, $CO_2$) was added into the oxidizer to find the critical concentration and the effectiveness of the agents on flame extinction. The experimental results showed that the physical aspect of inert gases was main mechanism for flame blow-out as same as cup burner test, but the flow effect should be considered to determine the extinction concentration. The numerical prediction was performed with modified WSR model and the result was in good agreement with the measurements. The experimental and numerical methods could be used for the assessment of various flame suppression agents such as minimum extinguishing concentration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.157-158
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• 2007

Effects of post-metallization anneal (PMA) on interface trap characteristics of Si-$SiO_2$ are studied. The conventional PMA method utilizes forming gas anneal, where 10% hydrogen in nitrogen atmosphere is used. A new PMA method utilizes hydrogen rich PECVD- silicon nitride $(SiN_x)$ film as a hydrogen diffusion source and a out-diffusion blocking layer. It can be shown through charge pumping current measurement that the new PMA is indeed effective to decrease Si-$SiO_2$ interface trap density.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.5
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• pp.1-8
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• 2019

Breath analysis using a portable device is better than the classical breath analysis system in terms of installation and operation. There is an increasing need to develop cost-effective equipment for testing gas sensors from the viewpoint of functionalities that can be applied applicable to portable devices. In the present study, an economical gas chamber for in-situ gas measurement is implemented with a single gas chamber without using expensive gas storage and control equipment; the gas response characteristics are analyzed using the above-described chamber. The main features of the implemented gas chamber are simple injection procedure, improved gas diffusion, easy measurement and cleaning, support for low-power mode measurement function for portable devices, and open source platform. Moreover, an analysis of gas response characteristics based on changes in sensor voltage show that the sensitivity and 90% response time are affected by the sensor voltage. Furthermore, the sensitivity graph has an inflection point in a specific range. The gas sensor applied in this study showed fast response speed and high sensitivity for sensor voltages of 3.0-3.5 V, regardless of the concentration of acetone gas, the target gas used in this study.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.2
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• pp.55-58
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• 2003

This paper examines the electrical characteristic of single oxide layer due to various diffusion conditions, substrate orientations, substrate resistivity and gas atmosphere in a diffusion furnace. The oxide quality was examined through the capacitance-voltage characteristic due to the annealing time after oxidation process, and the capacitance-voltage characteristics of the single oxide layer by will be described via semiconductor device simulation.