• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.1
• /
• pp.64-71
• /
• 2015

This paper deals with analysis of armature reaction magnetic field of linear generator with three phases coreless/cored type concentrated winding. On the basis of a magnetic vector potential and Maxwell's equations, governing equations to predict armature reaction field are derived, and current density modeling is also performed analytically by using the Fourier series expansion. The analytical method used in this paper is confirmed by comparing with finite element analysis results.

• Journal of Ocean Engineering and Technology
• /
• v.7 no.2
• /
• pp.162-172
• /
• 1993

In the present paper, the overall state of the arts of ice mechanics which is the most typical research topic of the artic engineering field was studied. And also, ice loads genrated by ice-structure interaction were estimated using numerical approach. The effects of viscous property of ice sheets to the ice load were investigated. The time dependent deformation behaviors of ice was modeled by visco-plastic problem using the finite element formalism. Constitutive model representing the material properties of ice was idealized by comblned rheological model with Maxwell and Voigt models. Numerical calculations for the bending and crushing behavior of ice sheet which are the most typical interaction modes between ice sheets and structures were carried out. The time dependent viscous behaviors of ice sheets interaction forces acting on structures were analyzed and the results were studied in detail.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.5
• /
• pp.94-101
• /
• 1996

The purpose of this paper is to analyze the field distribution and the current distribution of leaky coaxial cable with the finite difference-tiem domain(FDTD) algorithm. finite difference equations of maxwell's equations are defined in cylindrical coordinate systems. To simulate the unbounded problem like a free space, the Mur's absorbing boundary conditon is also used. After modeling the leaky coaxial cable with the three dimensional grid structure, the transient resoponse of th efield distribution and the current distribution are depicted in the time domain.

• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.2
• /
• pp.58.2-58.2
• /
• 2017

The special session of the East Asian Observatory was prepared to let the Korean Astronomical Community know the current status and future prospect of the EAO, and to hear the opinion from the community. The East Asian Observatory (EAO) was formulated on September 5, 2014 by East Asian Core Observatories Associations (EACOA) as a non-profit company registered in the State of Hawaii. As a first mission of the EAO, it has successfully operated the James Clerk Maxwell Telescope (JCMT) since March 2015. The Submillimeter Array (SMA) has been available to the East Asian astronomers from 2017A season through the EAO, and the Subaru and the East Asian VLBI Network (EAVN) are the possible facilities to be available in near future.

• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.2
• /
• pp.79.1-79.1
• /
• 2017

The B-fields In STar-forming Region Observations (BISTRO) is the 3-year large program of the James Clerk Maxwell Telescope (JCMT) using SCUBA-2 and POL-2, started in 2016. We aim to study the roles of magnetic fields in star formation by observing 16 fields of nearby star forming regions, e.g., Orion and Ophiuchus molecular clouds. The angular resolution and wavelength provided by JCMT (14 arcsecond at 850 micrometer) is ideal to investigate the intermediate scales of magnetic fields (1000-10000 au) associated in cold dense cores and filaments. This year, moreover, we were awarded JCMT time for additional 16 fields (BISTRO-2), which allows us to cover broader physical properties of star forming regions. We report the current status of BISTRO and introduce BISTRO-2.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.14 no.5
• /
• pp.102-106
• /
• 2015

In this paper, we study the optimal design for improved rotation latch system performance. The factors affecting the Torque generated in the armature were chosen as design variables. Utilizing the vertical matrix, the orthogonal array table was created to predict the results through minimal analysis. To confirm the Torque generation amount, by utilizing the commercial electromagnetic analysis software MAXWELL, finite element analysis was performed. The approximation method and experimental design through the commercial PIDO tool PIAnO for optimal design and calculations were utilized to perform experiments using an optimization method with evolutionary algorithms. Using the approximation model, design factors were determined that can maximize the torque generated in the armature, and the simulation was performed.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.1089-1093
• /
• 2003

The moving least square (MLS) basis is implemented for the real-space band-structure calculation of 2D photonic crystals. The value-periodic MLS shape function is thus used in order to represent the periodicity of crystal lattice. Any periodic function can properly be reproduced using this shape function. Matrix eigenequations, derived from the macroscopic Maxwell equations, are then solved to obtain photonic band structures. Through numerical examples of several lattice structures, the MLS-based method is proved to be a promising scheme for predicting band gaps of photonic crystals.

• Proceedings of the Korea Contents Association Conference
• /
• 2010.05a
• /
• pp.381-383
• /
• 2010

In order to solve electromagnetic boundary value problems efficiently, we prove the equivalence of tangential and normal boundary conditions. Using four Maxwell's equations simultaneously, we deduce the conditions to satisfy the equivalence of tangential and normal boundary conditions for electromagnetic waves. The conditions proposed in this work can be used to obtain the simultaneous equations of electromagnetic boundary value problems.

• 한국전산유체공학회:학술대회논문집
• /
• 2006.10a
• /
• pp.101-105
• /
• 2006

The computational fluid dynamic analysis has been conducted for the thermo-chemical flow field in an arcjet thruster with mono-propellant Hydrazine (N2H4) as a working fluid. The Reynolds Averaged Navier-Stokes (RANS) equations are modified to analyze compressible flows with the thermal radiation and electric field. The Maxwell equation, which is loosely coupled with the fluid dynamic equations through the Ohm heating and Lorentz forces, is adopted to analyze the electric field induced by the electric arc. The chemical reactions of Hydrazine were assumed to be infinitely fast due to the high temperature field inside the arcjet thruster. The chemical and the thermal radiation models for the nitrogen-hydrogen mixture and optically thick media respectively, were incorporated with the fluid dynamic equations. The results show that performance indices of the arcjet thruster with 1kW arc heating are improved by amount of 180% in thrust and 200% in specific impulse more than frozen flow. In addition to thermo-physical process inside the arcjet thruster is understood from the flow field results.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.848-853
• /
• 2001

Electrostatic actuation was adopted for ease of fabrication. We proposed a new driving scheme that uses the vector sum of force generated by comb-finger and by parallel plate. The moving and fixed electrodes are arranged to maximize the driving force. In this paper, an electrostatic field analysis is performed by Maxwell analysis tool for micro actuators. From the analysis, a comb-parallel type micro-actuator with 4${\mu}{\textrm}{m}$ width, 6${\mu}{\textrm}{m}$ overlap and 45${\mu}{\textrm}{m}$ height could be designed. In order to compare the new type of actuator with the conventional comb type of actuator, we arranged that both types have the same area and the same number of actuators. To make a high aspect ratio structure, we are developing fabrication process using SU-8 and electro-plating.