• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.295-298
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• 2002

In the analysis of the mass distribution and SMD (Sauter Mean Diameter), planar laser imaging technique Is a convenient and useful one when compared to the mechanical patternator or PDPA (Phase Doppler Particle Analyzer). But for the accurate usage of this laser technique, it is required to compensate the signal attenuation and to find the attenuation coefficients. In the present research, we considered effects of the spray distributions on the attenuation coefficient and improved the accuracy of planar laser imaging technique by the reduction of errors issuing from the signal attenuation.

• 전기전자학회논문지
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• 제17권3호
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• pp.360-364
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• 2013

The maximum breakdown voltage's characteristic within the Super Junction MOSFET structure comes from N-Drift and P-Pillar's charge balance. By developing P-Pillar from Planar MOSFET, it was confirmed that the breakdown voltage is improved through charge balance, and by setting the gate voltage at 10V, the characteristic comparisons of Planar MOSFET and Super Junction MOSFET are shown in picture 6. The results show that it had the same breakdown voltage as Planar MOSFET which increased temperature resistance by 87.4% at $.019{\Omega}cm^2$ which shows that by the temperature resistance increasing, the power module's power dissipation improved.

• 한국전기전자재료학회논문지
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• 제25권4호
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• pp.261-265
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• 2012

IGBT(insulated gate bipolar transistor) is outstanding device for current conduction capabilities. IGBT design to control the large power switching device for power supply, converter, solar converter, electric home appliances, etc. like this IGBT device can be used in many places so to increase the efficiency of the various structures are coming. in this paper optimization design of planar type IGBT and planar field stop IGBT, and both devices have a comparative analysis and reflection of the electrical characteristics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.276-278
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• 1997

The reliable etching process is one of the essential steps in fabricating GaN based-device. High etch rate is needed to obtain a deeply etched structure and perfect anisotropic etched facet is needed to obtain lasing profile. In the research, therefore, we had proposed a planar inductively coupled plasma etcher (Planar ICP Etcher) as a high density plasma source, and studied the etching mechanism using the $CH_4/H_2$/Ar gas mixture. Dry etching characteristics such as etch rate, anisotropic etching profile and so on, for the III-V nitride layers were investigated using Planar ICP Etcher, based on the plasma characteristic as a variation of plasma process parameters.

• 대한산업공학회지
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• 제35권2호
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• pp.129-140
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• 2009

This paper introduces the planar storage location assignment problem (PSLAP) that no research has attempted to mathematically solve. The PSLAP can be defined as the assignment of the inbound and outbound objects to the storage yard with aim of minimizing the number of obstructive object moves. The storage yard allows only planar moves of objects. The PSLAP usually occurs in the assembly block stockyard operations at a shipyard. This paper formulates the PSLAP using a mathematical programming model, but which belongs to the NP-hard problems category. Thus this paper utilizes an efficient genetic algorithm (GA) to solve the PSLAP for real-sized instances. The performance of the proposed mathematical programming model and developed GA is verified by a number of numerical experiments.

• 대한기계학회논문집A
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• 제30권2호
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• pp.171-178
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• 2006

Experimental and theoretical study of the non-planar response motions of a circular cantilever beam subject to base harmonic excitation has been presented in this paper work. Theoretical research is conducted using two non-linear coupled integral-differential equations of motion. These equations contain cubic linearities due do curvature term and inertial term. A combination of the Galerkin procedure and the method of multiple scales are used to construct a first-order uniform expansion for the case of one-to-one resonance. The results show that the non-linear geometric terms are very important for the low-frequency modes of the first and second mode. The non-linear inertia terms are also important for the high-frequency modes. We present the quantitative and qualitative results for non-planar motions of the dynamic behavior.

• Journal of Mechanical Science and Technology
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• 제15권3호
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• pp.309-319
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• 2001

This paper demonstrates the development of optical temperature sensor based on the etched silica-based planar waveguide Bragg grating. Topics include design and fabrication of the etched planar waveguide Bragg grating optical temperature sensor. The typical bandwidth and reflectivity of the surface etched grating has been ∼0.2nm and ∼9%, respectively, at a wavelength of ∼1552nm. The temperature-induced wavelength change is found to be slightly non-linear over ∼200$^{\circ}C$ temperature range. Typically, the temperature-induced fractional Bragg wavelength shift measured in this experiment is 0.0132nm/$^{\circ}C$ with linear curve fit. Theoretical models with nonlinear temperature effect for the grating response based on waveguide and plate deformation theories agree with experiments to within acceptable tolerance.

• 대한수학회지
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• 제42권4호
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• pp.847-856
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• 2005

M. Junger, G. Reinelt, and W. R. Pulleyblank asked the following questions ([2]). (1) Is it true that every simple planar 2-edge connected bipartite graph has a 3-partition in which each component consists of the edge set of a simple path? (2) Does every simple planar 2-edge connected graph have a 3-partition in which every component consists of the edge set of simple paths and triangles? The purpose of this paper is to provide a positive answer to the second question for simple outerplanar 2-vertex connected graphs and a positive answer to the first question for simple planar 2-edge connected bipartite graphs one set of whose bipartition has at most 4 vertices.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.781-786
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• 1996

In this paper, output precision characteristic of planar 3 and 6 degree-of-freedom parallel mechanisms are investigated. The 6 degree-of-freedom mechanism is formed by adding an additional small link along with an actuated joint in each of serial subchain of the 3 degree-of-freedom mechanism. First, kinematic analysis for two parallel mechanisms are performed, then their first-order kinematic characteristics are examined via isotropic index and minimum velocity transmission ratio of the mechanisms. It can be concluded that the planar 6 degrees-of-freedom parallel mechanism can be very effectively employed as a high-precision macro-micro manipulator from the analysis results when its link lengths are properly chosen.

• 한국정밀공학회지
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• 제20권4호
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• pp.59-67
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• 2003

This paper presents a new approach for the use of smart materials, piezoelectric materials of PVDF and PZT, for vibration attenuation of a planar parallel manipulator. Since lightweight linkages of parallel manipulators deform under high acceleration/deceleration, an active damper is needed to attenuate vibration due to structural flexibility of linkages. Based on the dynamic model of a planar parallel manipulator, an active damping controller is developed, which consists of a PD feedback control scheme, applied to linear electrical motors, and a linear velocity feedback (L-type) scheme applied to either PVDF layer or PZT actuator(5). Simulation results show that piezoelectric materials yield good damping performance, resulting in precise manipulations of a planar parallel manipulator.