• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1884-1886
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• 2001

In this study, we fabricated Al mirror driven by electromagnetic force. Because the mirror has Ni staple joint, it reduces the deflection angle of torsion spring for the maximum deflection of mirror. Therefore the magnetic field for maximum deflection can be reduced, By additional electrostatic force, the deflection angle of mirror plate can be increased to $90^{\circ}$. The fabricated mirror is actuated by electromagnetic force of a simple solenoid. The maximum deflection angle by magnetic field is about $86^{\circ}$ with $1.2{\times}10^4$ A/m.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.321-321
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• 2010

In this paper, we propose a novel type shaft-less ring type ultrasonic motor. A traveling wave rotary type ultrasonic motor is selected as a base model. The newly designed stator has two piezoelectric ceramic rings which are bonded in sandwich shape as traveling wave generator. So, we can expect to produce higher torque. The proposed model has the rotor structure that coupled with the stator provokes the pressure, this model do not install the separate plate any spring device. We used the finite element method to verify the operation principle and to compute the vibration mode of proposed model.

• Structural Engineering and Mechanics
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• v.74 no.5
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• pp.577-588
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• 2020

A unified solution is presented for the buckling analysis of rectangular laminated composite plates with elastically restrained edges. The plate is subjected to biaxial in-plane compression, and the boundary conditions are simulated by employing uniform distribution of linear and rotational springs at all edges. The critical values of buckling loads and corresponding modes are calculated based on classical lamination theory and using the Ritz method. The deflection function is defined based on simple polynomials without any auxiliary function. The verifications of the current study are carried out with available combinations of classic boundary conditions in the literature. Through parametric study with a wide range of spring factors with some classical as well as some not classical boundary conditions, competency of the present model of boundary conditions is proved.

• Journal of Applied Reliability
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• v.11 no.1
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• pp.31-41
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• 2011

A strut mount is an important part of vehicles which reduces the vibration and the impact transmitted from the wheels while supporting a shock absorber and a coil spring. Rubber compounding, shape design, and process design technologies are important components to improve the functionality of a strut mount such as durability, static, dynamic, and torsional characteristics. Among them the rubber compounding technology is the key technology which dominates the quality of a strut mount. In this study a strut mount with high reliability has been developed by adopting new rubber compounding and improving the shape of the inner plate and the isolator. Through the tests for prototypes it has been shown that the durability has been improved more than 2.5 times, from about 60,000 cycles to about 160,000 cycles.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2003.11a
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• pp.41-46
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• 2003

In recent days, it is usual case to extend the dwelling area to the balcony which is provided by service area. But the use of the extended area can be arisen discomfort with a view point of thermal environment by excessive heat accumulation in summer and excessive cold draft in winter. In this study, the skills were reviewed to improve the thermal environment of the extended area and evaluations were carried out. Additional heat supply by heat-convector installed at the lower end of the curtain wall can improve the thermal environment of the extended area and also arise surface temperature of the curtain wall surface. And aluminum plate installed under the floor could not improve the thermal environment but it was effective to shortening the initial heating time.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2004.11a
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• pp.147-152
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• 2004

With the life style changing and the income level improving in our society, the composition of apartment residents and the preference are diversifying. For that reason, various residential plans are desired. However in bearing wall system the existing apartments have a clear attribute of a fixed system, consequently, they have a difficulty in being adapted to the social requirement. In this research, 1 would like to put a variable apartment to practical use in which with a suitable structure system applied to a variable apartment considered as remodeling system various residential requirements are accepted and the change of the family life cycle and moreover, effective and systematic remodeling are accomplished.

• Transactions of Materials Processing
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• v.19 no.4
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• pp.203-209
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• 2010

In the hot press forming process (HPF), a martensitic structure is obtained by controlling the cooling rate when cooling a boron sheet that is heated up to over $900^{\circ}C$. The HPF process has various advantages such as the improvement in formability and material properties and minimal spring back of the deformed materials. The factors related to the cooling rate depend on the heat transfer characteristics between heated materials and dies. Therefore, in this study, the cooling rate is controlled by adjusting the heat transfer coefficient of the material at the pressing process. And, the mechanical properties and microstructure of the deformed material is demonstrated during the HPF process where cold dies are used to form the heated steel plate. This is achieved by varying the major forming conditions that control the cooling rate regarded as the most important process parameter.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.177-183
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• 2008

For 10 kW-class Stirling engine using scroll expander and scroll compressor, considerations on thermal expansion of the fixed and orbiting scroll members of the scroll expander due to high gas temperature at the expander inlet has resulted in adopting of the keys between the fixed scroll and main frame for the fixed scroll side and spring type insertion between the orbiting scroll base plate and supporting holders for orbiting scroll side. Dynamic analysis on the fixed and orbiting scroll members and the shafts of the scroll expander showed that using of these devices for complying thermal expansion caused large variations of the forces acting on the fixed scroll keys and on the power transmitting shafts and also on the shaft bearings.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2260-2262
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• 2000

In this paper, micromirror which can rotate 45 degree is designed, analyzed and fabricated. The micromirror is parallel to the substrate initially. When external magnetic field is applied, a micromirror can rotate to align its easy axis to the field. The size of micromirror array is $10{\times}10$. The mirror plate and spring is made of aluminium, and nickel is used as soft magnetic material. To obtain 45 degree angular deflection, dimension ratio between stopper length and thickness of sacrificial layer is properly selected. By using electrostatic force, individual actuation is possible.

• Journal of Life Science
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• v.10 no.1
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• pp.74-78
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• 2000

This study was investigated to evaluate the distribution of airborne microorganisms at underground shops in Seomyun and Nampodong, Pusan. The number of bacterial colonies on the nutrient agar plate plates were calculated by the open petri dish method for 30 minutes in indoor air of underground shops at every seasons in a year. There was no statistically significant difference between Seomyun and Nampodong in mean colony counts. Isolation rates of Gram positive rods was highest, and Gram positive cocci and Gram negative rods were followed. In Nampodong underground shops, Enterobacteriaceae strains was isolated. Mean colony counts according to seasons was higher at summer and autumn in Seomyun, and spring and winter in Nampodong. In near future, a study on the distribution of bacteria causing respiratory infection should be followed.