• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.9
• /
• pp.1315-1322
• /
• 1993

본 연구에서는 헤어핀 공진기를 이용하여 L대역 대역통과 MIC여파기를 설계하였다. 여파기의 크기를 줄이기 위해 헤어핀 공진기 간의 결합을 일반결합 대신에 안쪽견합 또는 혼합결합을 사용할 누 있다. 안쪽결합을 사용한 4개의 공진기로 된 여파기는 일반결합 여파기 보다 크기가 20~30% 감소되었다.

• Proceedings of the KAIS Fall Conference
• /
• 2010.05b
• /
• pp.606-609
• /
• 2010

본 연구를 통해 각 업체에 공급되고 있는 제품 중 세계최고 수준의 품질과 정밀도를 갖는 몰리브덴 핀 제품과 동등 하거나 이상의 제조기술의 개발을 최종목표로 진행하였다. 1년간의 연구개발을 통해 몰리브덴 핀의 생산기술을 셋업 하였으며, 시 제작품의 제작을 완료하였다. 현재 시작품은 전극업체에서 전극으로 제작되어 램프 수명 테스트를 진행 중에 있으며 수명테스트가 완료되면 본격적인 양산이 진행될 것으로 기대하고 있다.

• Tribology and Lubricants
• /
• v.23 no.3
• /
• pp.95-102
• /
• 2007

In recently designed diesel engines, the running conditions for piston pin bearings have become very severe due to combustion pressure and temperature increase. Moreover, the lead removal from the bush material has strongly reduced the capability of the anti friction material to accept asperity contacts. In this paper, before trying to find the pressure distributions on the oil film of piston pin bearings by the unsteady two dimensional thermohydrodynamic lubrication analysis in order to do the optimum design of the bearings of piston pin, it will be investigated the tendancy of piston pin rotating motion by calculating the friction coefficient at piston pin bearings, the oil film thickness and the frictional torques induced by hydrodynamic shear stress.

• Tribology and Lubricants
• /
• v.24 no.3
• /
• pp.133-139
• /
• 2008

In recently designed diesel engines, the running conditions for piston pin bearings have become very severe due to combustion pressure and temperature increase. In this paper, it will be investigated the tendency of piston pin rotating motion by calculating the friction coefficient at piston pin bearings, the oil film thickness and the frictional torques induced by hydrodynamic shear stress. Finally, the pressure distributions on the oil film of piston pin bearings will be found by two-dimensional lubrication analysis in order to help the optimum design of the bearings of piston pin. Specially, it is investigated the effects on the film pressure distribution due to the change in maximum combustion pressure.

• Tribology and Lubricants
• /
• v.24 no.2
• /
• pp.55-62
• /
• 2008

In recently designed diesel engines, the running conditions for piston pin bearings have become very severe due to combustion pressure and temperature increase. In this paper, it will be investigated the tendency of piston pin rotating motion by calculating the friction coefficient at piston pin bearings, the oil film thickness and the frictional torques induced by hydrodynamic shear stress. Finally, the pressure distributions on the oil film of piston pin bearings will be found by two-dimensional lubrication analysis in order to help the optimum design of the bearings of piston pin. Specially, it is investigated how the changes in combustion pressure at exhaust and intake stroke and the pressure-viscosity index effect on the film pressure distribution.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2004.10a
• /
• pp.500-504
• /
• 2004

The bio-micro pin has been usually used for the biochemistry analysis. The manufacturing capability of the micro-pin and the their array with the effective and low-cost way is very important and it gives great economical benefits to developers. The micro-pin is composed of the sample channel for holding the liquid with the fixed volume, the flat tip which determines the printing quality and the pin head for preventing the rotation of the pin in the holder. In this study, we have manufactured newly designed micro-pins by the wire-EDM process with special jigs, and analyzed liquid holding and printing characteristics with respect to the variation of the shape and the tip size of the micro-pin.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.15 no.10
• /
• pp.860-869
• /
• 2003

Design optimization of the heat sink with 7${\times}$7 square pin-fins is performed numerically using the Computational Fluid Dynamics (CFD) and the Computer Aided Optimization (CAO). In the pin-fins heat sink, the optimum design variables for fin height (h), fin width (w), and fan-to-heat sink distance (c) can be achieved when the thermal resistance ($\theta$$_{j}$) at the junction and the overall pressure drop ($\Delta$p) are minimized simultaneously. To complete the optimization, the finite volume method for calculating the objective functions, the BFGS method for solving the unconstrained non-linear optimization problem, and the weighting method for predicting the multi-objective problem are used. The results show that the optimum design variable for the weighting coefficient of 0.5 are as follows: w=4.653 mm, h=59.215 mm, and c=2.667 mm. In this case, the objective functions are predicted as 0.56K/W of thermal resistance and 6.91 Pa of pressure drop. The Pareto optimal solutions are also presented.re also presented.d.

• Journal of Advanced Marine Engineering and Technology
• /
• v.31 no.4
• /
• pp.394-400
• /
• 2007

The properties and weldability of lap joints by PFSW with 1050 Al sheet was investigated according to tool shape. dimension and welding condition. Tensile shear test was carried out for lap jointed specimen, and the hardness in the joint regions was examined. Moreover interfacial joining length, metallograph and failure location of the lap-jointed cross section were discussed. Two tool types were a simple cylindrical type and a notched cylindrical type. Under joining conditions such as plunging depth of 2.2mm. rotating speed of 1600rpm and dwelling time of 3s, the tensile shear strength of lap-jointed specimen by the notched type tool was superior to that by simple cylindrical type tool. The maximum tensile shear load of lap jointed specimen was 5807N. Optimal dimensions of the notched type tool were as follows : diameters of the shoulder and pin were $18{\phi}mm$ and $10{\phi}mm$, and pin length was 2.2mm.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.3
• /
• pp.235-241
• /
• 2014

As a fiber-optic cable is being unwound, it is protected by a tube that is designed to prevent unwinding problems such as tangling and unintentional cutting. In addition, a guide body is separated from the protective tube if a shear pin breaks when the maximum allowable load is exceeded. Therefore, it is important to analyze and predict the unwinding behavior of the protective tube, as well as the load on the shear pin, to enhance the likelihood of a successful operation when laying cables at extreme depths. In this study, the protective tube and the guide body are modeled with particles and are constrained with a constant-length constraint. The load on the shear pin was verified against experimental data, and the unwinding behavior was predicted from the load prediction results.

• Journal of Welding and Joining
• /
• v.24 no.6
• /
• pp.1-4
• /
• 2006