• 대한기계학회논문집B
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• 제23권11호
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• pp.1444-1452
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• 1999

The turbulence structure of e. tip vortex generated by e. fixed wing was investigated with the use of two-dimensional laser Doppler velocimetry. The velocity field, composed of circumferential end axial components, was measured on the vertical section to the vortex trail, located at 2C downstream from the wing tip in the incoming flow condition of $Re=2.24{\times}10^5$. A quasi 3-dimensional measurement technique by use of 2-dimensional LDV system was suggested for Reynolds stresses and the higher moments. The validity of this technique was confirmed with the uncertainty analysis. The budget of the turbulence kinetic energy was analyzed by those results in the radial direction of the vortex core. It is resulted that the production is to be very likely balanced with the dissipation in most range of the vortex core.

• 한국생산제조학회지
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• 제20권4호
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• pp.434-439
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• 2011

There are about 2.4million disabled in Korea, 2009. Also, Korean society entered into an aging society. Therefore disable and elderly are getting more involved in our society. This study proposes simple ramp design for wheel chair users and welding method and condition for manufacturing. In the middle of ramp, screw jack and motor are installed so that ramp can be moved left and right side. To make the ramp moves easily, ramp was fixed by installing LM guide on both sides. Ramp production for using Nd:YAG laser certain dissimilar welding in stainless steel sheet and cold reduced carbon steel. The output was fixed by 3kW, the speed was increased to 2~7m/min, Argon was used as shielding gas and the flow rate was changed to 10~30L/min. The proper welding condition is the output 3kW and welding speed 2~5m/min.

• 한국자동차공학회논문집
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• 제9권3호
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• pp.9-17
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• 2001

This paper is the second of 3 companion papers which investigate axial stratification process. In-cylinder fuel behavior has been investigated in the port injected Sl engine by visualizing for the purpose of understanding stratification. Planar laser light sheet from an Nd:YAG laser has been illuminated through the transparent quartz cylinder of the single cylinder optical engine and the Mie scattered light has been captured through the quartz window in the piston head with an ICCD camera. Fuel has been replaced with an air-ethanol mixture to utilize atomized fuel spray fur the visualization purposes. This results have been compared with steady flow concentration measurement. For low/medium swirl port, the early injection makes such a fuel distribution state that is upper-rich, middle-lean and lower-rich along the combustion chamber and cylinder by tumbling motion. On the other hand, the late injection induces upper-rich, middle-lean and lower-rich state due to the short fuel penetration.

• 한국자동차공학회논문집
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• 제9권3호
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• pp.18-26
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• 2001

This paper is the third of 3 companion papers which investigate axial stratification process. In-cylinder fuel behavior has been investigated in the port injected SI engine by visualizing for the purpose of understanding stratification. Planar laser light sheet from an Nd:YAG laser has been illuminated through the transparent quartz cylinder of the single cylinder optical engine and the Mie scattered light has been captured through the quartz window in the piston head with an ICCD camera. Fuel has been replaced with an air-ethanol mixture to utilize atomized fuel spray for the visualization purposes. This results have been compared with steady flow concentration measurement. In high swirl port, the most fuel remains at combustion chamber and upper cylinder region without being affected by injection timing. The macro-distributed state is not changed but the difference of the amount of fuel around the spark plug varies according to injection timing, which determines LML.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 2006년도 제28회 동계학술발표회 논문집
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• pp.170-186
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• 2006

The guarantee funds for government policy fund, venture capital investment fund, technology guarantee debt are the core parts of the external financing system in the constant technology innovation company. However, the enterpriser's requirement to keep the technology innovation with minimized management intervention and policy maker's hope to advance technology development with clear operation of funds is enough to request for research of the project investment plan to the R&D project. This paper will analyze whether technology innovation company that creates cash flow prefers to the project investment as a financing program or not, and if prefers, what characters of company affect on this preference. The more the company that pursuit the additional R&D activity separated to on-going items becomes over the fixed size, the more prefers the project investment as future external fund-raising. Together with that, this paper suggests that we can apply the plan like special purpose vehicle, SWORD(Stock Warrant Off-Balance sheet R&D) and R&D Limited Partnership as R&D project investment policy, and improve the system itself.

• 소성∙가공
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• 제15권6호
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• pp.428-435
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• 2006

IC leadframe needs precision shape for good efficiency. Friction conditions also have a significant impact on blanking deformation. Therefore, studying the friction produced by the tribology between die and materials becomes necessary. In this study, in order to measure mechanical properties and frictions for leadframe materials such as Ni alloys and coppers, tensile test and straight pulling friction test are executed. In particular, the effect of clearance on the blanking characteristics depending on friction coefficient is examined by finite element simulation. From the finite element simulation, the metal flow, side pressure of punch and crack initiation are evaluated according to the leadframe materials.

• 한국식품영양과학회지
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• 제25권6호
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• pp.1087-1093
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• 1996

국내 및 해외에서의 멸치액젓 관련 제품의 가공공정과 포장에 대하여 살펴 본 후 멸치액젓의 표준화된 가공과 품질관리를 위해 새로운 가공공정 및 포장방법을 제시하였다. 제시된 방법에서는 원료 멸치를 소금과 혼합한 다음(염도 20%), 온도조절된 상태에서 발효숙성시키고, 여과 혹은 원심분리, 여과잔사를 염수첨가 후 2차 발효시켜서 재여과하여 1차 여과액과 혼합시키고, 용기에 포장하고 저온에서 살균하는 과정에 의해 구성되도록 설계되었다. 여과잔사 폐기물의 처리 문제도 함께 고려하였다.

• Carbon letters
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• 제16권3호
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• pp.183-191
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• 2015

Gas transport through graphene-derived membranes has gained much interest recently due to its promising potential in filtration and separation applications. In this work, we explore Kr-85 gas radionuclide sequestration from natural air in nanoporous graphene oxide membranes in which different sizes and geometries of pores were modeled on the graphene oxide sheet. This was done using atomistic simulations considering mean-squared displacement, diffusion coefficient, number of crossed species of gases through nanoporous graphene oxide, and flow through interlayer galleries. The results showed that the gas features have the densest adsorbed zone in nanoporous graphene oxide, compared with a graphene membrane, and that graphene oxide was more favorable than graphene for Kr separation. The aim of this paper is to show that for the well-defined pore size called P-7, it is possible to separate Kr-85 from a gas mixture containing Kr-85, O₂ and N₂. The results would benefit the oil industry among others.

• 대한기계학회논문집B
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• 제26권5호
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• pp.716-723
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• 2002

Heat transfer in linear motor driven stages for surface mounting device applications was investigated. A simple one-dimensional thermal resistance model (TRM) was introduced. In order to reduce three-dimensional nature to one-dimensional, a few assumptions and simplifications were employed suitably. A good agreement with a finite element heat transfer analysis in temperature profile was obtained. For validation, the analysis was compared with the measurement with respect to motor driving power. Overall discrepancy was less than 7$^{\circ}C$. The influence of two high thermal resistance parts, insulation sheet and thermal contact between the coil assembly and the mounting plate, was examined through the analysis. Additionally, the thermal resistance analysis was applied to another stage including an internal cooling-air passage, and was found available for this system as well. After validation, the cooling effect was surveyed in terms of motor power, and cooling-air and -water flow rate.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.96-101
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• 2001

Heat transfer in linear motor driven stages for surface mounting device applications was investigated. A simple one-dimensional thermal resistance model was introduced. In order to reduce three-dimensional nature to one-dimensional, a few assumptions and simplifications were employed suitably. A good agreement with a finite element heat transfer analysis in temperature profile was obtained. For validation, the analysis was compared with the measurement with respect to motor driving power. Overall discrepancy was less than $7^{\circ}C$. The influence of two high thermal resistance parts, insulation sheet and thermal contact between the coil assembly and the mounting plate, was examined through the analysis. Additionally, the thermal resistance analysis was applied to another stage including an internal cooling-air passage, and was found available for this system as well. After validation, the cooling effect was surveyed in terms of motor power, and cooling-air flow rate.