• Title/Summary/Keyword: Air gap

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Comparison of old-old aged women's pants basic pattern using 3D data (3차원 계측데이터를 활용한 고령 여성의 팬츠 원형 비교)

  • Cha, Su-Joung
    • The Research Journal of the Costume Culture
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    • v.26 no.3
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    • pp.360-376
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    • 2018
  • The purpose of this study was to make a pants pattern suitable for women 70 to 85 years of age, then analyze that- pattern's shape, size, appearance, fit, allowance and air gap. Participants made the pattern using 3D simulation program DC Suite version 5.1. The results suggest a design method suitable for the lower-body shapes of elderly women. In external appearance, the A-type earned the highest evaluation in all items except the allowance of the back waist and back hip. The L type earned the highest evaluation in the allowance of back waist and hips. The A-type's, back waist appeared set at an angle that did not match the body shape of an old-old aged woman in the center-back-line setting. Therefore, the pattern method of A-type combined with L-type's method of center back, produces an excellent pants pattern. Evaluation of the air gaps among patterns revealed that; the A-type showed the largest air gap in waist and hip circumference and the smallest air gap in thigh circumference. The waists, abdomen, and hip circumferences of older women often become larger while their legs become slimmer. This study accounted for those factors in determining a pattern suitable for the lower-body shape of old-old aged women. However, participants only analyzed four patterns and compared them with women 70 to 85, years of age. Therefore, it is necessary to develop industrial patterns applicable to a wide age group.

Development of the Spark-gap Switch with Dual Trigger System (쌍방향 시동방식의 고속투입스위치 개발)

  • Kim, Maeng-Hyeon;Seo, Yun-Taek;Park, Seung-Jae;Park, Byeong-Rak;Go, Ui-Seok
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.49 no.7
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    • pp.359-364
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    • 2000
  • This paper is introducing a newly developed spark-gap switch with dual trigger system, into which the current from the voltage source is injected along with the test sequence during the synthetic testing of high voltage circuit-breaker. The currently-used spark gap switch is narrow in operating range due to the use of the method of triggering energy being injected by single way. As a result, the frequent happening of misoperation has greatly reduced the test quality and test efficiency and has required the cost of maintenance excessively. In this study, accordingly, in order to basically remove these problems, another triggering system is installed to the opposite direction on the existing triggering system; attaching the same time and the same rising time of pulse wave as on the existing system, so that at a comparatively trigger gap distance from the main electrode(the gap can be operated at 60% of self-break voltage, while at 80% in the current system), the main electrode has been enabled to be closed by the development of spark gap switch with dual trigger system.

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High Speed Segmental Stator Type 4/3 SRM: Design, Analysis, and Experimental Verification

  • Hieu, Pham Trung;Lee, Dong-Hee;Ahn, Jin-Woo
    • Journal of Electrical Engineering and Technology
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    • v.12 no.5
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    • pp.1864-1871
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    • 2017
  • This paper presents a design of a 2-phase segmental stator type 4/3 switched reluctance motor (SRM) for air-blower application. The air-blower requires only one direction rotation, high rotor speed without torque dead-zone. In order to satisfy the requirements of the load, the rotor of the 4/3 proposed SRM is designed with wider rotor pole arc and non-uniform air-gap is applied on the rotor shape. With a special rotor structure, the motor generates a wider positive torque region and has no torque dead-zone. The stator of the proposed SRM is constructed with two segmental C-cores, and there are no magnetic connections between 2 C-cores. The flux follows in a short closed loop in each C-core and has no reversal flux in the stator. The static and dynamic characteristics of the proposed motor are analyzed by the finite element method (FEA) and Matlab-Simulink, respectively. In order to verify the design, a prototype of the proposed motor has manufactured for laboratory test. The performance of the proposed motor is verified by the simulation and experimental results.

RF MEMS 기법을 이용한 US PCS 대역 FBAR BPF 개발

  • 박희대
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.3
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    • pp.15-19
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    • 2003
  • In This paper, we developed 1.96 GHz air gap type FBAR BPF using ZnO as piezoelectric sputtered by RF magnetron at room temperature. FBAR BPF was fabricated by sputtering bottom electrode (Al), ZnO as piezoelectric and top electrode (Mo) on Si wafer one by one with RF magnetron sputter, then Si was dry etched to make an air hole. XRD test result of fabricated FBAR BPF showed that ZnO crystal was well pre-oriented as (002) and sigma value of XRC was 1.018. IL(Insertion loss) showed excellent result as 1 dB.

AlN Based RF MEMS Tunable Capacitor with Air-Suspended Electrode with Two Stages

  • Cheon, Seong J.;Jang, Woo J.;Park, Hyeon S.;Yoon, Min K.;Park, Jae Y.
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.13 no.1
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    • pp.15-21
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    • 2013
  • In this paper, a MEMS tunable capacitor was successfully designed and fabricated using an aluminum nitride film and a gold suspended membrane with two air gap structure for commercial RF applications. Unlike conventional two-parallel-plate tunable capacitors, the proposed tunable capacitor consists of one air suspended top electrode and two fixed bottom electrodes. One fixed and the top movable electrodes form a variable capacitor, while the other one provides necessary electrostatic actuation. The fabricated tunable capacitor exhibited a capacitance tuning range of 375% at 2 GHz, exceeding the theoretical limit of conventional two-parallel-plate tunable capacitors. In case of the contact state, the maximal quality factor was approximately 25 at 1.5 GHz. The developed fabrication process is also compatible with the existing standard IC (integrated circuit) technology, which makes it suitable for on chip intelligent transceivers and radios.

Flow Visualization of Magnetic Particles under the external magnetic field in bubbly flow using Single Plane Illumination Microscopy - MicroPIV (Single Plane Illumination Microscopy - MicroPIV를 이용한 버블 유동에서 외부 자계 영향을 받는 자성입자 가시화)

  • Lee, Changje;Cho, Gyeong-rae;Lee, Sangyoup
    • Journal of the Korean Society of Visualization
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    • v.19 no.1
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    • pp.36-42
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    • 2021
  • This study measured the velocity of magnetic particles inside the power generation using external heat sources. Single Plane Illumination Microscopy (SPIM) was used to measure magnetic particles that are simultaneously affected by bubbly flow and magnetic field. It has the advantage of reducing errors due to particle superposition by illuminating the thin light sheet. The hydraulic diameter of the power generation is 3mm. Its surface is covered with a coil with a diameter of 0.3 mm. The average diameter of a magnetic particle is 200nm. The excitation and emission wavelengths are 530 and 650nm, respectively. In order to find out the flow characteristics, a total of four velocity fields were calculated in wide and narrow gap air bubbles, between the wall and the air bubble and just below the air bubble. Magnetic particles showed up to 8.59% velocity reduction in the wide gap between air bubbles due to external magnetic field.

Wireless Power Charging System Capable of Soft-Switching Operation Even in Wide Air Gaps (넓은 공극범위에서 소프트스위칭 동작하는 무선전력 충전시스템)

  • Yu-Jin, Moon;Jeong-Won, Woo;Eun-Soo, Kim;In-Gab, Hwang;Jong-Seob, Won;Sung-Soo, Kang
    • The Transactions of the Korean Institute of Power Electronics
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    • v.27 no.6
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    • pp.515-525
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    • 2022
  • The wireless power transfer (WPT) charging system for AGV depends highly on the coupling conditions due to air gap variation. To attain stable output power with high transfer efficiency under various coupling conditions, a single-stage, DC-DC converter that operates with robustness to changes in air gaps is proposed for the WPT system. The proposed converter is capable of soft switching under the set input voltage (Vin: 380 VDC), load conditions (0-1 kW), and air gap changes (30-70 mm). In addition, a wide output voltage range (Vo: 39-54 VDC) can be controlled by varying the link voltage due to the phase control at a fixed switching frequency. Experimental results are verified using a prototype of a 1 kW wireless power charging system.

A Study on the Active Control of Air Bearing (공기베어링의 능동제어에 관한 연구)

  • Lee, Jeong-Bae;Kim, Kyung-Woong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.8
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    • pp.2501-2507
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    • 1996
  • In this paper actively controlled air bearing is investigated to overcome the defects of air bearing such as low stiffness and damping coefficients. The actively controlled air beairng is composed of an air bearing, a gap sensor, a controller, and a piezo actuator. By controlling the position of air bearing with piezo actuator, the position of floating object is controlled. In this study the proportional-Integral-Derivative controller is employed. Active air bearing is investigated numerically and experimentally. There is good agreement between the simulation and the experimental results. It is shown that the stiffness and damping characteristics and positioning experimental results. It is shown that the stiffness and damping characteristics and positioning accuracy of air bearing can be improved by means of adopting actively controlled air bearing.