• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권3호
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• pp.130-136
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• 2003

Crowbar system Vacuum switches, widely used In a pulsed power system, could use the magnetic force to prevent the electrode damage. Vacuum switches using the magnetic forces are classified roughly into RMF(Radial Magnetic Field) and AMF(Axial Magnetic Field) type. The RMF type switches restrain a main electrode from aging due to high temperature and high density arc by rotating the arc which is driven by the Lorenz force. The AMF type switches generate axial magnetic field which decreases the electrode damage by diffusing arc. In this paper, we present the energy loss characteristics of both RMF and AMF type switches which are made of CuCr(75:25 wt%) electrodes. The time-dependent dynamic arc resistance of high-current pulsed discharge in a high vacuum chamber(~10$^{-6}$ Torr). which occurs in RMF and AMF type switches, was obtained by solving the circuit equation using the measured values of the arc voltage and current. In addition, we compared energy loss characteristics of both switches. Based on our results, it was found that the arc voltage and the energy loss of an AMF type switch are lower than a RMF type switch.

• Journal of Magnetics
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• 제18권3호
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• pp.289-296
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• 2013

This work presents results of the study which concerns the influence of the rotating magnetic field (RMF) on the growth rate, cell metabolic activity and ability to form biofilms by E. coli and S. aureus. Liquid cultures of the bacteria were exposed to the RMF (RMF frequency f = 1-50 Hz, RMF magnetic induction B = 22-34 mT, time of exposure t = 60 min, temperature of incubation $37^{\circ}C$). The present study indicate the exposition to the RMF, as compared to the unexposed controls causing an increase in the growth dynamics, cell metabolic activities and percentage of biofilm-forming bacteria, in both S. aureus and E. coli cultures. It was also found that the stimulating effects of the RMF exposition enhanced with its increasing frequencies and magnetic inductions.

• 정보보호학회논문지
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• 제32권6호
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• pp.1183-1192
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• 2022

정보 및 정보를 생산, 처리, 폐기하는 시스템은 정보의 총수명주기에 걸쳐 일정수준의 보안이 유지되어야 한다. 일정수준의 보안을 유지하기 위해 소프트웨어 및 자동차 개발, 미국 연방정부 정보체계 등 시스템 수명주기의 보안관리 프로세스를 적용하고 있으나, 우리나라에는 이와 유사한 보안관리 프로세스가 전무한 실정이다. 본 논문에서는 국방 분야 정보 및 정보 처리시스템의 총수명주기에 걸쳐 일정수준의 보안을 유지하기 위한 한국형 보안위험관리 프레임워크를 제안한다. 국방 분야에 적용할 수 있는 한국형 보안위험관리 프레임워크의 개발 목적과 적용방안을 소개함으로써 향후 국방 보안업무가 나가야 할 방향을 제시하고 보안 패러다임의 전환을 유도하고자 한다

• Journal of Magnetics
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• 제21권1호
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• pp.141-147
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• 2016

Staphylococcus aureus cultures exposed to rotating magnetic field (RMF) were studied in order to analyse the possible induced changes in staphylococcal enterotoxin genes (se) expression. Liquid cultures of S. aureus strains carrying different se were exposed to the RMF of magnetic frequency 50 Hz and magnetic induction 34 mT for 10 h at $37^{\circ}C$. Three time points of bacterial growth cycle were considered for RNA extractions. Gene expression analyses were evaluated using real-time quantitative PCR method. The present study confirmed, that the RMF can stimulate the growth rate of S. aureus cultures in comparison to the unexposed controls, while the stimulation is not strain dependent. The studies have also shown, that the RMF, depending on the exposure time but regardless the bacterial strain, can influence on the expression of various se. In general, except for sea, as a result of bacterial exposure to the RMF through subsequent growth phases, the expression of se decreased, reaching the values below results recorded for unexposed controls. In the case of sea expression remained at a lower level as compared to the control, regardless the time of exposition.

• Journal of Electrical Engineering and Technology
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• 제11권2호
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• pp.377-382
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• 2016

In this paper, influence of vibration on cogging torque and Radial Magnetic Force(RMF) imbalance was investigated in the IPM type BLDC motor. Design of cogging torque reduction and the RMF equilibrium was proceed applied to Design of Experiment(DOE). Vibration test results, the RMF imbalance was confirmed that a significant impact of vibration.

• 전기학회논문지
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• 제62권11호
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• pp.1535-1540
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• 2013

In this paper, the Radial Magnetic Force(RMF) and cogging torque which cause vibration and noise in IPM type BLDC motor were analyzed. The cogging torque and RMF cause electromagnetic vibration. So, a notch was installed for the equilibrium of RMF and cogging torque reduction. The notch was analyzed by using a Fourier Series for the energy distribution of the air-gap. The equilibrium of RMF and the reduction of cogging torque were performed by a Design Of Experiment(DOE) with the notch. Also, operating characteristics and efficiency were analyzed and compared.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.25-32
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• 1998

Most recent seismic design codes include Response Modification Factor(RMF) for determining equivalent lateral forces. The RMF is used to reduce the linear elastic design spectrum to account for the energy dissipation capacity, overstrength and damping of the structure. In this study the RMF is defined as the ratio of the absolute maximum linear elastic base shear to the absolute maximum nonlinear base shear of a structure subject to the same earthquake accelerogram. This study investigates the effect of hysteretic model, as well as target ductility ratio and natural period on duct based RMF using nonlinear dynamic analyses of the SDOF systems. Special emphasis is given to the effects of the hysteretic characteristics such as strength deterioration and stiffness degradation. Results indicate that RMFs are dependent on ductility, period and hysteretic model.

• Metals and materials international
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• 제24권6호
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• pp.1275-1284
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• 2018

A rotating magnetic field (RMF) was applied in the solidification process of Cu-8Fe alloy. Focus on the mechanism of RMF on the solid solution Fe(Cu) atoms in Cu-8Fe alloy, the influences of RMF on solidification structure, solute distribution, and material properties were discussed. Results show that the solidification behavior of Cu-Fe alloy have influenced through the change of temperature and solute fields in the presence of an applied RMF. The Fe dendrites were refined and transformed to rosettes or spherical grains under forced convection. The solute distribution in Cu-rich phase and Fe-rich phase were changed because of the variation of the supercooling degree and the solidification rate. Further, the variation in solute distribution was impacted the strengthening mechanism and conductive mechanism of the material.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.321-326
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• 2013

This paper investigates the magnetic excitation force of a surface-mounted permanent magnet (SPM) motor according to the change of pole/slot combination. The characteristics of magnetic flux and radial magnetic force (RMF) due to pole/slot combination were analyzed by using magnetic circuit analysis. Also, the RMF of motors with the variable pole/slot combination was numerically simulated by using the finite element analysis to verify the result of the magnetic circuit analysis. This research shows that RMF ripple is reduced when the number of pole is smaller than the number of slot.

• 전기학회논문지
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• 제65권2호
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• pp.298-303
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• 2016

In this paper, the vibration source of IPM type BLDC motor was analyzed by finite element method. The main causes of the electrical vibration were RMF(Radial magnetic force) and cogging torque. It was designed model of minimized cogging torque and RMF equilibrium. Design models were selected the optimum model using the design of experiment method. And, the vibration experiment was carried out through prototype machine of each model. Finally, the experimental results were compared with the analysis ones.