• 한국조명전기설비학회지:조명전기설비
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• 제6권5호
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• pp.27-37
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• 1992

We studied the dielectric and dynamic mechanical losses according to the quenching condition in low density polyethylene being used to power cables. According to severe quenching condition, characteristics of the temperature in internal friction los peak have decreased the magnitude of loss peak as amorphous region lengthen. From now on, the frequency dependent characteristics of dielectric loss have investigated at room temperature, and the dielectric loss peak due to interface polarization, between crystal and amorphous region, occurs about 30[Hz], and that, the peak due to orientation polarization in correspondence to the loss peak in internal friction has observed at about 3 [MHz]. As quenching velocity increased, the effect on quenching condition about the dielectric loss has decreased the magnitude of the loss peak. Thus, estimation has been carried out on the activation energies nd the degree of crystallinity by means of X-ray diffraction are obtained as follows: room quenching : 26.4 [kal/mole] and 54.73 [%], ice quenching : 25.6 [kcal/mole] and 48.47 [%], liquid nitrogen quenching specimens : 22.56 [kcal/mole] and 40.95 [%].

• 한국전기전자재료학회논문지
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• 제11권7호
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• pp.557-564
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• 1998

A low loss x-cut $LiNbO_3$optical waveguide was fabricated by Yi in-diffusion, and the properties of guided-mode and the total insertion loss of the pigtailed waveguide with polarization maintaining fiber(PMF) were measured at optical wavelength 1550nm. for forming the waveguides, the parameters of diffusion, Ti thickness, waveguide line-width, length, diffusion temperature, time and atmosphere were set $1400{\AA}$, $8{\mu}m$, 3.3cm, $1050^{\circ}C$, 8 hours and wet bubbled oxygen, respectively. And then after the polishing and piatailing, it showed that the total insertion loss was -4.1dB for TM mode, -5.5dB for TE mode, and mode size, that is, the horizontal/ vertical size were $13.8{\mu}m/18{\mu}m$ for TM mode, $9.6{\mu}m/6.5{\mu}m$ for TE mode.

• 한국사회복지학
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• 제65권2호
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• pp.335-356
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• 2013

이 연구는 저소득층이 겪는 물리적 자원에서의 상실과 획득이 안녕감에 어떠한 영향을 주는지 그리고 이들이 경제환경과 상호작용하며 경험하는 경제적 안정감이 그러한 상실 및 획득의 영향을 받아 안녕감에 어떠한 역할을 하는지를 탐색하고자 하였다. 이에 자활센터를 이용하는 저소득층 남녀 성인 254명을 대상으로 물리적 자원의 상실과 획득, 경제안정, 안녕감의 수준을 살펴보고, 자원의 상실 및 획득 각각이 안녕감에 영향을 주는 관계와 이 관계에서 경제안정 수준이 보이는 매개역할을 구조방정식모형 분석으로 검토하였다. 주요 연구결과는 첫째, 참여자들은 물리적 자원을 약간 잃거나 얻은 수준이고 획득이 상대적으로 높았다. 둘째, 경제안정 및 안녕감과의 관계에서 자원상실은 유의한 부적관계를, 획득은 유의한 정적 관계를 보였다. 셋째, 자원상실은 경제안정과 안녕감 각각에 대해 유의한 부적인 직접효과를 보인 한편 경제안정의 감소를 통해 안녕감을 감소시키는 간접효과도 유의하였다. 끝으로, 자원획득 역시 경제안정과 안녕감 각각에 대해 유의한 직접효과를 보이고 또 경제안정을 통한 정적인 간접효과가 유의하여 자원상실과 획득 두 모형 모두에서 부분매개모형이 지지되었다. 이러한 결과에 기초하여 사회복지실천에서 저소득층 성인의 생활과 밀접히 관련되는 물리적 자원의 상실 및 획득, 경제안정, 안녕감을 활용할 방안과 조사연구에서 가질 수 있는 함의를 찾고 제언하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권6호
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• pp.290-295
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• 2001

The transport loss of a Bi-2223 tape exposed to external magnetic fields was investigated. The results show that the transport loss is independent on voltage lead arrangements in case the magnetization loss is compensated. A serous increase of the transport loss due to external AC magnetic field is observed. The loss is described well by dynamic resistance loss in relatively high fields, but another mechanism than the dynamic resistance must be responsible for the increase of the loss in low fields. The transport loss is also dependent strongly on the orientation of the external fields.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.61-64
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• 2005

The packet loss problem that occurs in the mobile multicast (MoM) protocol due to designated multicast service provider (DMSP) handoff is investigated through simulation experiments for several DMSP selection policies. Then, two enhanced DMSP schemes are proposed to minimize the packet loss of the MoM protocol with single DMSP. The first scheme uses a backup DMSP and greatly reduces the packet loss rate at the expense of the increased network traffic. The second scheme utilizes the extended DMSP operation and shows many desirable features such as the almost-zero packet loss rate and relatively low network traffic.

• 한국유체기계학회 논문집
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• 제10권2호
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• pp.46-53
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• 2007

An improved performance characteristics analysis model of a regenerative pump is proposed in the present paper. For its low characteristic speed, a regenerative pump generates high head with low flow rate. However, the efficiency is fairly low due to the skin friction between impeller and casing. Also, the complexity of its internal flow pattern makes prediction of performance characteristics difficult. In the present research, a one-dimensional analysis model was improved with consideration of disc friction loss, minor loss, and modified flow length, and the result was proven to be close in range with the results from experiments.

• 대한기계학회논문집
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• 제17권8호
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• pp.2110-2121
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• 1993

A numerical investigation has been carried out for the flow characteristics after exchange of some filters from the original layer to the new low pressure loss layer with equal filtering efficiency. The solution domain includes upper plenum, filter layer, clean space, access panels, and lower plenum. The concept of the distributed pressure resistance was applied to describe the momentum loss in filter layer and access panels. The evolution of the flow field is simulated using the low Reynolds number k-.epsilon. over bar turbulent model and SIMPLE algorithm based on the finite volume method. As a result, after the exchange of filter layer the power requirement can be reduced by 8-9 percent. The results also demonstrate that the perpendicularity of the flow near access panels may become worse at new filter layer than origianl filter layer. But the situation can be recovered by adjusting the jopening ratio of access panels.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 춘계학술발표대회 논문집
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• pp.241-246
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• 2008

In this paper, we analyze the I-V curve and hot-spot phenomenon caused by solar cells' serial and parallel connected circuit. The mis-match loss of parallel interconnection with low Isc string decrease lower than serially interconnected one and temperature caused by hot-spot does. Also, mis-match loss of parallel interconnection with low Voc string increase more than serially interconnected one. The string having low Voc happened hot-spot phenomenon when open circuit. The bad solar cell in string gives revere bias to good solar cell and make hot-spot phenomenon. If we consider the mis-match loss, when designing PV module and array. the efficiency of PV system might increase.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 춘계종합학술대회
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• pp.489-492
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• 2000

This paper describes a new transient voltage suppressor(TVS) with a low insertion loss and a very wide frequency bandwidth to protect antenna circuit from transient voltages. Conventional protection devices have some problems such as low frequency bandwidth and high insertion loss. In order to improve these limitations, a coaxal type TVS, which consists of a gas tube is developed. The performance of the proposed transient voltage suppressor is tested by using a combination surge generator specified in IEC 61000-4-5 standard and by using a network analyzer of 40 MHz ∼ 5GHz bandwidth. From the experimental results, it is confirmed that the proposed TVS has an enough protection performance in low insertion loss and in wide frequency bandwidth

• International journal of advanced smart convergence
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• 제9권2호
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• pp.105-113
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• 2020

In this paper, we proposed a soft switched synchronous boost converter, which can perform discharging the battery, is proposed. The proposed converter has low switching loss even at high frequency operation due to its soft switching characteristics. The converter operates in synchronous mode to minimize conduction loss because of changing the rectified diode to MOSFET with a low on resistance. In this reason, the efficiency of the converter can be greatly improved in high frequency. In this paper, the battery discharger with a switching frequency of 100 kHz, has been designed. The designed converter also simulated to prove the converter's characteristics of synchronous operation as well as soft switching operation. The simulation shows that the proposed converter always meets the soft switching conditions of turning on and off switching in the zero voltage and zero current states. Therefore, simulation results have confirmed that the proposed battery discharge had soft switching characteristics. The simulation results have confirmed that the proposed battery discharger had soft switching and synchronous operation characteristics.