• Proceedings of the KIEE Conference
• /
• 1996.07a
• /
• pp.216-218
• /
• 1996

In this paper, it is treated the design and characteristics analysis of the voice coil type LOA which is composed of a voice coil type mover and permanent magnets. The design is acomplished using FEM analysis to make up the magnetic circuit. And the characteristics of LOA are analyzed to be used on the control system for the earthquake-proof experiments.

• Proceedings of the KIEE Conference
• /
• 1998.07d
• /
• pp.1534-1536
• /
• 1998

We designed and fabricated plate-type linear ultrasonic motor. It used multi-vibration mode, 1st Longitudinal and 4th Bending mode. To analyze vibration mode and find maximum displacement point, we simulated using FEM(Finite Element Method). The plate-type linear ultrasonic motor was fabricated by the simulation results. Also, to confirm application to card-forwarding device, frequency and load characteristics were measured. Its resonance frequency was 49.6 kHz, and its maximum speed was about 0.6m/s when no load. Also, its maximum efficiency was 1.2 % and in that time, speed and torque was 0.3 m/s and 0.7 mNm, respectively.

• Proceedings of the KIEE Conference
• /
• 1996.11a
• /
• pp.15-18
• /
• 1996

In the case of need for reciprocating motion, the study for application of Linear Oscillating Actuator(LOA) is being accomplished. LOA is the simpler and more efficient than other linear apparatus using the rotary motor because LOA produce the thrust force without any converter such as cam, clutch, rack, pinion and belt, etc. We designed the flat moving core type LOA and manufactured for trial. This paper shows the structure and dynamic characteristics of LOA.

• Proceedings of the KIEE Conference
• /
• 1998.11a
• /
• pp.52-54
• /
• 1998

LOA is the linear electromechanical device that mover is similar to secondary conductor of LIM. The mover reciprocates along stroke by supplying the alternating current to primary coil. LOA is the simpler and more efficient than other linear apparatus using the rotary motor because LOA produce the thrust force without any mechanical converter such as cam, clutch, belt, rack and pinion, etc. This paper deals with the static characteristics of moving coil type LOA by virtual work method, FEM analysis and experiment Results show that thrust force increases when mover travels form center to both ends.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.40 no.11
• /
• pp.93-98
• /
• 2003

In this paper, we designed a printed square loop antenna for operating of PCS and IMT2000 band. The proposed antenna has omni-directional radiation patterns with broad bandwidth, similar to the conventional antenna, to easy feed on composing single planar. We obtain an ideal impedance matching and increase bandwidth. An antenna bandwidth is about 150MHz(1.74∼l.89〔GHz〕) at 1$^{st}$ resonance frequency and 290MHz(1.95∼2.24GHz) at 2$^{nd}$ resonance frequency on VSWR(equation omitted)1.5, and then we can obtain not only 1.73∼l.87 〔GHz〕 PCS band but also 1.92∼2.17 (GHz) IMT2000 band. band.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.51 no.7
• /
• pp.292-297
• /
• 2002

In this paper, a flat-type $L_{-}$-$B_{8}$ mode Ultrasonic Motor[USM] having the size of 80 x 20 x ${1.5}mm^3$($l{\times}\omega{\times}t$) was designed and fabricated to examine the characteristics of an ultrasonic vibration. We used ANSYS simulation program based on FEM to get the optimum design of this USM. As results of experiment, the fastest speed of revolution(v), the maximum torque(T) and the efficiency(n) were 37.5cm/s, 5.0 mN.m and 1.17% when 27.9KHz, 150N, 50V were applied respectively. And this flat-type $L_{-}$-$B_{8}$ mode USM could be controlled the speed of rotor revolution by applied voltage, frequency and pre-load of rotor as well as showed the characteristics of typical drooping torque-speed, large torque and high speed. So, we think that this flat-type $L_{-}$-$B_{8}$ mode USM has characteristics of enough torque and velocity to be usable for applications in forwarding device of an electric card or a paper, etc.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.11a
• /
• pp.414-417
• /
• 2001

Recently, developments of device using characteristics of ceramics as a new technical material is in progress. While doing so, Ultrasonic motor which is a part of research & flat-type $L_1-B_8$ mode Ultrasonic motor and measured the operation characteristics of its. The size of USM is 80*20*1.5[$mm{^1}$](length*width*thickness) and is constructed with stator by piezo-ceramics and stainless elastic body and rotator by bearings. As results of experiments, the fastest speed of revolution($\upsilon$), the maximum torque(T) and the efficiency($\eta$) were 37.5[cm/sec], 5.0[mN$\cdot$M] and 1.17[%] respectively when 27.9[kHz], 150[gf], 50[V] were applied. SO, we think this flat-type $L{_1}-B{_8}$ mode Ultrasonic motor is able to be used for applications in forwarding device of a paper or electric card so on. Key Words: Flat=type $L{_1}-B{_8}$ mode Ultrasonic Motors, Piezoelectric ceramics, forwarding device.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.39 no.4
• /
• pp.343-350
• /
• 2015

The natural convection heatsink is the most commonly used cooling device, especially for high-power LED lights, because of its reliability and low long-term cost. High power LED lights are generally used in an inclined configuration for street lamps and security lamps. However, it was difficult to estimate the thermal performance of an inclined heatsink, because the results from previous studies are not applicable to the inclined configuration. In this study, we measured the thermal performance of an inclined cylindrical heatsink with plate fins. Various fin numbers, fin heights, base temperatures, and inclination angles ($30^{\circ}$ and $60^{\circ}$) were examined. Based on the experimental results, the Nusselt number correlation is presented. This correlation is applicable when the Rayleigh number, ratio of the fin height to cylinder diameter, and fin number are in the ranges 100,000-600,000, 1/6-1/2, and 9-72, respectively.

• Proceedings of the KIEE Conference
• /
• 1996.07a
• /
• pp.50-52
• /
• 1996

The exiting apparatus for rectilinear reciprocating motion has low efficiency because of various mechanical converting equipments from rotary motion. The LOA(Linear Oscillation Actuator) is the rectilinear reciprocating actuator. This paper shows the operating principle of bifiler winding LOA and the comparison the characteristics of thrust force of no tapered moving core type LOA with the tapered one. Through FEM analysis tapered LOA has the lower peak force and longer stroke than no tapered LOA.

• Proceedings of the KAIS Fall Conference
• /
• 2009.12a
• /
• pp.846-849
• /
• 2009

본 논문에서는 듀얼 밴드(UHF: 470-862 MHz, L: 1452-1492 MHz) DVB-H 안테나를 제작하였다. 제안된 안테나는 입력 임피던스 매칭 회로를 이용한 평판형 역 F 안테나(PIFA)로 구성되었다. 급전점에 구성된 매칭 회로는 안테나의 광대역(UHF: 470-862 MHz: 63%) 동작특성을 만족시킨다. 제시된 안테나는 전방향적 방사특성을 가지며 상용 모바일(PMP)에 적용가능한 충분한 이득(최대이득: 1.70dBi)을 보인다. 또한 안테나는 유전율($\varepsilon_r$ = 3.2)인 PMP 케이스에 부착되어 상용 모바일용으로 소형화 되었다.