• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 학술대회 논문집 정보 및 제어부문
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• pp.151-152
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• 2008

Laser has been applied in various diagnostic and therapeutic medical fields. For last few decades, medical low-level laser devices have been introduced in market, but they have limitations which cannot convey enough energy to deep layer of tissues for diagnostic or therapeutic purposes. To address the issue, there have been many studies of using physical and chemical methods; it is one of ways to apply negative or positive pressure to tissue. However, it is hard to apply desired pressure on tissues continuously when practical laser devices arc used. In this study, we introduce a low-level laser probe which allows maintain pressure on skin tissue. Consequently, we are confident that the pressure probe for low-level laser treatment should be a useful tool in order to deliver sufficient energy for practical uses.

• 한국분말재료학회지
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• 제19권1호
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• pp.19-24
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• 2012

The consolidation results of fine tungsten powders, W-Cu composite and W/Cu FGM by using a novel method combining resistance sintering with ultra high pressure have been reviewed. The densification effects of the consolidation parameters, including pressure, input power and sintering time, have been investigated. The sintering mechanism of this method was quite different from other sintering methods. Particle rearrangement, sliding, distortion and crushing due to the ultra high pressure are the dominant mehanisms at the initial stage, then the dominant sintering mechanisms are transient arc-fused processes controlled by the input power.

• International Journal of Korean Welding Society
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• 제1권1호
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• pp.1-6
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• 2001

This paper describes several advances in sensor and process control techniques for applications in Submerged Arc Welding (SAW), which combine to give a fully automatic system capable of controlling and adapting the overall welding process. This technology has been applied in longitudinal and spiral pipe mills and in pressure vessel production.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.837-840
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• 1988

We study both theoretically and experimentally the motion of fluid driven by electro-thermally ablated gas pressure in a cavity with a single exhauster. A possibility of jet propulsion engine for steamers is also discussed as an application of the fluid motion.

• Journal of Welding and Joining
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• 제26권1호
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• pp.63-68
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• 2008

This paper has aimed to prevent excessive heat input by controlling arc distribution and heat input capacity with pulse GTAW in order to improve weld quality in 0.08mm pressure gauge diaphragm and flange welding parts. A design of experiment was designed using Box-Behnken method to optimize a welding process. The pulse GTAW parameters such as pulse current, base current, pulse duty, frequency and welding speed were set to input variables while hydraulic pressure that represents welding characteristics in diaphragm and flange joint were set to output variables. Based on the test result, a second regression equation was obtained between input and output variables and turned out significant. Besides, an influence of parameters has been confirmed through response surface analysis using the second-order regression equation and optimum welding condition was obtained through a grid-search method. The optimum welding condition was set to pulse current 84.4(A), base current 29.6(A), pulse duty 58.8(%), frequency 10(%), and welding speed 596(mm/min). Then, decent bead shape was acquired with no excessive heat input under the $2.3kgf/cm^2$ of hydrostatic pressure.

• Journal of Welding and Joining
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• 제33권3호
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• pp.68-74
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• 2015

Superduplex stainless steels are important materials to the oil and gas industry, especially for off-shore production. TIG welding of super duplex stainless steels to obtain the optimal phase balance between austenite and ferrite is mainly achieved by controlling the cooling rate and the weld chemistry. The latter depends on the filler wire chosen and the shielding gas used. If TIG welding of superduplex stainless steels is performed with argon shielding gas only, then nitrogen gets lost from the weld pool, which can result in a ferrite-rich weld metal, with an inferior corrosion resistance than parent metal. In the present study, nitrogen permeation model from the shield gas which gets into the weld metal in DCEN-TIG welding has suggested. This plasma stream model shows characteristics of permeation of nitrogen ions into the molten metal due to the strong physical effect of plasma stream which formed by the arc pressure rather than the permeation of nitrogen ions caused by electric effect.

• 대한기계학회논문집
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• 제12권3호
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• pp.457-465
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• 1988

본 연구에서는 벨트 연삭시 즉 집중하중을 받는 평벨트 구동에서 벨트와 풀리 사이의 내접촉 특성을 구하고자 하였다.준 정적평형(quasi-static equilibrium) 상 태에서 벨트구동계의 이론적 해석을 하여 집중하중점을 포함한 벨트-풀리 전접촉구간 에서 벨트장력분포를 구하고 이 결과를 실험치와 비교하였다. 본 연구에서는 집중하 중점 보다는, 집중하중의 벨트-풀리 전접촉구간에 대한 영향을 밝히는데 주안점을 두 었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1669-1671
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• 1997

Liquid nitrogen has many adventages. It is cheaper than other cooling medium. It is easy to obtain high purity. It's utilized with easy. In future, liquid nitrogen is able to be accepted cooling medium for the superconducting and cryogenic applicated equipments. Cryogenic liquid may be atmospheric pressure state because thermoinsulation is ineffective, airtight decreasing by long time using and bubble occured by flowing current. If it is to be atmospheric pressure state, the electrical insulation strength is dropped and processed partial discharge, finally breakdown. Processing of breakdown has anticipated by measuring radiated-electromagnetic wave which is happened in time of breakdown. There is a measurement of radiated electromagnetic wave as a method that proceeding breakdown is anticipated. In this paper, radiated electromagnetic wave was measured in arc discharge by above conditions as a basic experiment.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 춘계학술대회
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• pp.241-246
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• 1995

An experimental investigation was performed under steady flow condition to assess hydrodynamic performance of floating-type monoleaflet polymer valves (MLPV) with different leaflet thickness. The St. Jude Medical valve (SJMV) was also used for comparison tests. Pressure drops of MLPVs are larger than those for other types of polymer valves and mechanical valves. Furthermore, the thicker is the leaflet thickness of a polymer valve, the larger arc the corresponding press drop. The velocity profiles for MLPV reveal a large reversed flow region downward to the valve position. The maximum wall shear stresses of MLPVs at a flow rate of 30 l/min are in the range $54-130\;dyn/cm^2$, and the corresponding maximum. Reynolds shear stresses are in the range of $100-500\;dyn/cm^2$, respectively. Both arc beyond the allowable limit clinically. In contrast, floating-type monoleaflet polymer valves show better hydrodynamic performance in leakage volume. From the designing point of view, it can be concluded that the optimum thickness of leaflet for better hydrodynamic performance is one of the important parameters.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.43-43
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• 2010

We have characterized the parametric and functional properties of live cell and cancer cell according to plasma treatment conditions using Atmospheric Pressure (AP) Plasma with uniquely designed low temperature arc-free unit. AP plasma system showed very highly efficient capabilities of reacting and interfacing directly with live and cancer cells. The parametric results with the types of gases, applied power, applied gap, and process times on cells will be presented in accordance with functional studies of the works. The growth of cancer cells is directly influenced by AP plasma exposure with evaluating plasma conditions in several human cancer cells and understanding how plasma exposure alters molecular signaling pathways. The cells exhibit a slower or faster growth rates compared with untreated cells, depending on the cell types. These results strongly support the conclusion that alterations in one or more of each gene are responsible, at least in part, for plasma-induced apoptosis in cancer cells. In addition, it also will be presented that AP plasma has an important role for the improvement of sensor performance due to excellent interface property between enzyme and metal electrode for bio sensor manufacturing process.