• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제48권7호
• /
• pp.369-375
• /
• 1999

This paper presents the novel low-performance single-phase voltage regulator which has common arm between the AC/DC and DC/AC power converters and adopts appropriate switching strategy, resulting in the reduction of the number of switching devices. Moreover, by introducing the method to replace the method to replace the conventional AC condenser in filter circuit with the new low-cost type using two DC condenser, the whole voltage regulator system can be more compact, simpler and less expensive than conventional ones. The fully digital controller is designed using high speed DSP, and the proposed system is validated through the experimental results.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2002년도 학술.기술논문발표회
• /
• pp.67-76
• /
• 2002

Self-leveling material(SLM) is one of the floor finishing materials which make flat surface like as water level by itself in a short time. So it is possible to increase construction speed and enhance economical efficiency. In this study, author intended to develop SLM for the industrial warehouse and factory loading heavy weight machinery and vehicles. The demanded properties for this type of SLM are above 20mm of flow value and above 300kgf/cm2 of 28-days compressive strength. To possess demended strength and fluidity, SLM have to be composed of many types of binders and chemical additives. So it is difficult to decide suitable mixing proportion of composition materials. In this study, author investigated the weight percentage effect of main composition materials for high-strength self-leveling material, by experimental design such as tables of orthogonal arrays and simplex design, and by statistical analysis such as analysis of variance and analysis of response surface. Variables of experiments were ordinary portland cement(OPC), alumina cement(AC), anhydrous gypsum(AG), lime stone(LS) and sand, and properties of tests were fluidity of fresh state and strength of hardened state. Results of this study are showed that suitable mix proportions of binders for the high strength self-leveling materials are two groups. One is 78~85.5% OPC, 7.5~9.5% AC, 9~12.5% AG and the other is 72.5~78% OPC, 9~12.5% AC, 13~l5% AG.

• 한국초전도ㆍ저온공학회논문지
• /
• 제14권1호
• /
• pp.4-7
• /
• 2012

Coated conductors have been developed to increase piece length and critical current for electric power applications. Otherwise, Many efforts were carried out to reduce AC loss of coated conductor for AC applications. Twisting and cabling processes are effective to reduce AC loss but, these processes can not be applied for tape shaped coated conductor. It is inevitable to have thin rectangular shape because coated conductor is fabricated by thin film deposition process on metal substrate. In this study, round shape superconducting wire was first fabricated using coated conductors. First of all, Ag coated conductor was used. coated conductor was slitted to several wires with narrow width below 1mm. 12ea slitted wires were parallel stacked on top of another until making up the square cross-section. The bundle of coated conductors was heat treated to stick on each other by diffusion bonding and then copper plated to make round shape wire. Critical current of round wire was measured 185A at 77K, self field.

• 반도체디스플레이기술학회지
• /
• 제7권2호
• /
• pp.63-67
• /
• 2008

The MgO protective layer plays an important role in plasma display panels (PDPs). Our previous work demonstrated that the properties of MgO thin film could be improved, which were deposited by ion beam assisted deposition (IBAD). However arc discharge always occurs during the IBAD process. To avoid this problem, oxygen neutral beam assisted deposition (NBAD) is used to deposit MgO thin films in this paper. The energy of the oxygen neutral beam was used as the parameter to control the deposition. The experimental results showed that the oxygen neutral beam energy was effective in determining in F/$F^+$ centers, crystal orientation, surface morphology of the MgO thin film, and the discharge characteristics of AC PDP. The lowest firing voltage $(V_f)$ and the highest secondary electron emission coefficient $(\gamma)$ were obtained when the neutral beam energy was 300 eV.

• 한국초전도ㆍ저온공학회논문지
• /
• 제1권2호
• /
• pp.30-36
• /
• 1999

Superconductors are dissipative when exposed to time-varying magnetic fields. To analyze the AC characteristics of a superconductor, one usually needs to know magnetization curves of it. Good magnetization curves can be obtained only in homogeneous magnetic filed. In This paper, we report the setup and test results of a magnetization measurement system, which consists mainly of frequency-variable power supply and homeogenous magnet with 7-cm long air gap. Special emphasis are foused on the design and fabrication of the magnet, which aims to give background magnetic fields, and on the overall characteristics of the system.

• 한국컴퓨터정보학회논문지
• /
• 제22권10호
• /
• pp.1-7
• /
• 2017

In this paper, the separation force measuring system is developed. The separation force aries due to adhesive strength between semiconductor epoxy molding compound(EMC) and the metal plate in semiconductor formed plate. In general, when removing the metal plate in semiconductor formed plate from semiconductor epoxy molding compound, excessive strength can result in a increase in semiconductor defect rates, or conversely, if too little force is exerted on the metal plate in semiconductor formed plate, the semiconductor production rates can decrease. In this study, the design criteria for the selection of the AC servo motor, the role of the ball screw, the relationship between the load cell and the ball screw, and the rate of deceleration are given. In addition, minimizing the reject rate of semiconductors and maximizing the semiconductor production rate are achieved through the standardization of the collected separation force data measured by the proposed system.

• 대한안전경영과학회:학술대회논문집
• /
• 대한안전경영과학회 2003년도 추계학술대회
• /
• pp.335-343
• /
• 2003

In the electrode fabrication of unit cell, it was ascertained that electrochemical characteristics were greatly increased with 90 wt.% of BP-20, 5 wt.% of Super P and 5 wt.% of mixed binder [P(VdF-co-HFP) : PVP =7 : 3] The self-discharge of unit cell showed that diffusion process was controlled by the ion concentration difference of initial electrolyte due to the characteristics of Electric Double Layer Capacitor (EDLC) charged by ion adsorption in the beginning, but this by current leakage through the double-layer at the electrode/electrolyte interface had a minor effect and voltages of curves were remained constant regardless of electrode material. The electrochemical characteristics of 2.3 V/3,000 F grade EDLC were as follows: 0.35 m of DC-ESR (100 A discharge), 0.14 mof AC-ESR (AC amplitude 100 mV), 2.80 Wh/kg (3.73 Wh/L) of energy density and 4.64 kW /kg (6.19 kW/L) of power density. Power output was compatible with electric vehicle applications, uninterrupted power supply and engine starter, in due consideration of Ragone relations.

• 대한전기학회논문지
• /
• 제43권7호
• /
• pp.1193-1205
• /
• 1994

This paper presents a fuzzy system that adaptively classifies subimages to four classes according to image activity distribution. In adaptive transform image coding, subimage classification improves the compression performance by assigning different bit maps to different classes. A conventional classification method sorts subimages by their AC energy and divides them to classes with equal number of subimages. The fuzzy system provides more flexible classification to natural images with various distribution of image details than does the conventional method. Clustering of training data in the input-output product space generated the fuzzy rules for subimage classification. The fuzzy system of small number of fuzzy rules successfully classified subimages to improve the compression performance of the transform image coding without sorting of AC energies.

• E2M - 전기 전자와 첨단 소재
• /
• 제9권7호
• /
• pp.702-707
• /
• 1996

In this paper, in order to improve the withstand voltage properties of epoxy resin, IPN(interpenetrating polymer network) method was introduced and the influence was investigated. The single network structure specimen(E series), simultaneous interpenetrating polymer network specimen(EM series) and pseudo interpenetrating polymer network(EMP series) specimen were manufactured. In order to understand the internal structure properties, scanning electron microscopy method was utilized, and glass transition temperature was measured. Also, AC voltage dielectric breakdown strength, tensile strength and impact strength were measured to investigate the influence upon electrical and mechanical properties. As a result, it was confirmed that simultaneous interpenetrating polymer network specimen was the most execellent.

• 한국정보컨버전스학회논문지
• /
• 제7권2호
• /
• pp.25-29
• /
• 2014

본 연구에서는 알코올 섭취가 눈의 생리기능과 안기능에 영향을 미치는 가를 알아보기 위해 알코올 섭취 전,후의 안압, 누액분비량, 입체시차, AC/A비, 폭주여력, 개산여력을 측정하여 다음과 같은 결과를 얻었다. 전체 대상자의 알코올 섭취 전 평균 안압은 15.14mmHg이고 알코올 섭취 후 평균 안압은 12.8mmHg로 평균 15.44% 감소하는 것으로 나타났다. 누액분비량은 알코올 섭취 전 검사대상자 평균 17.125mm에서 알코올 섭취 후 평균 9.875mm로 42.33%로 감소하는 것으로 나타났다. 입체시차는 알코올 섭취 전 40'에서 알코올 섭취 후 165'로 약 4배가량 증가하였다. AC/A비는 알코올 섭취 전 $5.40{\Delta}/D$, 알코올 섭취 후 $6.19{\Delta}/D$로 14.6% 증가하였고 폭주여력과 개산여력은 원거리, 근거리 모두 유의한 변화가 없는 것으로 나타났다.