• The Transactions of the Korean Institute of Power Electronics
• /
• v.5 no.2
• /
• pp.105-114
• /
• 2000

To chive a traveling wave type ultrasonic motor with the series""-resonant inverter, the external inductor is i lnserted between the motor and inverter. In $\psi$is paper, we proposed a novel 3Ilalysis method to design the 3 ~xternal inductor. An equivalent model of the ultrasonic motor is expressed, and a selection method of the , ;;eries inductor is proposed from the basis of the model. When the series inductor has an optimal value, it is v velified by computer simulation results that power is efficiently transmitted to the mechanical resonant c component in the motor. The frequency and speed characteristics of the ultrasonic motor are investigated by e experiments for several external inductors. The validity of the proposed method for selecting external inductor i is clarified.clarified.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07a
• /
• pp.111-114
• /
• 2003

In order to improve the surface uniformity and the conduction properties of the fabricated YBCO thick films, a system that applies alternating field vertically to the EPD field has been developed for the first time and applied to the electrophoretic deposition process. The applied alternating electric field caused a force to be exerted on each YBCO particle and resulted in a shaking of the particle in the direction of applied electric field, accomplishing a uniform particle orientation. The usual commercial electrical power was used for the vertically applied alternating voltage and the induced electric field was 25-120 V/cm at 60Hz. The thick film fabricated by the method developed in this paper showed better surface uniformity without crack and porosity and improved film characteristics such as critical temperature ($T_{c,zero}$ : 90 K) and critical current density ($2354\;A/cm^2$). Therefore, it is expected that the shaky-aligned electrophoretic deposition method can be used to fabricate superconductor films through a simpler process and at less expense.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.11b
• /
• pp.558-561
• /
• 2001

Vanadium oxide ($VO_x$) thin films are very good candidate material for uncooled infrared (IR) detectors due to their high temperature coefficient of resistance (TCR) at room temperature. But, the deposition of $VO_x$ thin films showing good electrical properties is very difficult in micro bolometer fabrication process using sacrificial layer removal because of its low process temperature and thickness of thin films less than $1000{\AA}$. This paper presents a new fabrication process of $VO_x$ thin films having high TCR and low resistance. Through sandwich structure of $VO_{x}(100{\AA})/V(80{\AA})/VO_{x}(500{\AA})$ by sputter method and post-annealing at oxygen ambient, we have achieved high TCR more than $-2%/^{\circ}C$ and low resistance less than $10K\Omega$ at room temperature.

• Proceedings of the KIEE Conference
• /
• 2002.07c
• /
• pp.1416-1418
• /
• 2002

In order to examine the thermal properties of the wire materials, we analyzed the shrinkage, the expansion and the form transformation, the surface structure according to the thermal deterioration temperature through the testing method for a heating shrinkage of Korean Industrial Standard(KS C 3004). For IV(600V grade polyvinyl chloride insulated wires), we measured the shrinkage and the expansion rate, analyzed the surface structure using SEM(Scanning Electron Microscope). In the result of this experiment, the shrinkage rate of IV 2.0mm covering was high in comparison with other wires. As the deterioration temperature rises gradually, the covering is molten and harden.

• Journal of Surface Science and Engineering
• /
• v.41 no.4
• /
• pp.129-133
• /
• 2008

Nitrogen and aluminum codoped ZnO(NAZO) thin films were grown on glass substrates with changing the nitrogen flow ratio by radio-frequency magnetron sputtering. The structural, optical, and electrical properties of the NAZO films were investigated. The surface morphologies and the structural properties of the thin films were analyzed by using the X-ray diffraction and scanning electron microscopy. The NAZO thin film, deposited at nitrogen flow ratio of 0%, showed a strongly c-axis preferred orientation and the lowest resistivity of $3.2{\times}10^{-3}{\Omega}cm$. The intensity of ZnO(002) diffraction peak was decreased gradually with increasing the nitrogen flow ratio. The optical properties of the films were measured by UV-VIS spectrophotometer and the optical transmittances for all the samples were found to be an average 90% in the visible range. Based on the transmittance value, the optical bandgap energy for the NAZO thin film deposited at nitrogen flow ratio of 0% was determined to be 3.46 eV. As for the electrical properties, the carrier concentration and the hall mobility were decreased, but the electrical resistivity was increased as the nitrogen flow ratio was increased.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2017.05a
• /
• pp.141-141
• /
• 2017

국제해사기구(International Maritime Organization)는 선박 평형수로 인하여 발생하는 환경문제를 방지하기 위하여 지난 2004년 선박 평형수 관리 협약을 제정하였고, 2016년 핀란드의 비준함에 따라 2017년 9월 8일부터 발효될 예정이다. 이 협약에 대응하기 위하여 선박 평형수 처리기술이 개발되어 승인이 되었다. 이중 수중방전을 이용한 기술은 화학약품의 첨가 등이 없어 경제적이고 내부에서 발생하는 OH라디컬, 자외선, 충격파, 전기장, 오존 등에 다양한 요소들에 의하여 수처리가 가능하고, 중화를 위한 첨가제 등이 필요없어 친환경적이다. 본 연구에서는 부산 항만 근처연안에서 채취한 바닷물을 대상으로 수중방전을 이용한 방법을 연구하였다. 실험방법은 그림1과 같이 Point to Point 방식의 전극을 꾸몄고, 용액은 1L이며, 전압은 8kV, 30kHZ로 가해주었다. 광학분석장비(OES)를 이용하여 수중방전시 발생되는 빛 분석을 하였다. 실험결과 OES분석 결과 살균작용하는 OH 라디컬이 발생하는 것을 확인할 수 있었다. 또한 실험 도중 시료를 채취하여 $35^{\circ}C$ 48시간동안 배양하였다. 배양 결과 시간이 경과함에 따라 미생물의 개체가 그림 2와 같이줄어두는 것을 확인할 수 있었다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.10a
• /
• pp.98-100
• /
• 2000

현대 사회는 웹이라는 것을 통하여 수많은 정보들을 얻을 수 있으며 시간과 공간을 초월하고 있다. 이러한 정보들 가운데 이미지, 동영상, 오디오, 텍스트 등을 실시간으로 동시에 제공받는 것은 아직도 웹 상에서는 한계가 있다. 이러한 한계를 극복하기 위해 W3C(World Wide Web Consortium)에서 XML 어플리케이션의 하나로서 SMIL (Synchronized Multimedia Integration Language)이란 표준화한 방안과 기술을 개발하였고, 이러한 표준화된 SMIL을 바탕으로 기존의 디지털 T.V, VOD, 웹 상에서의 멀티미디어 프리젠테이션 등과 같은 분야와 연계하고자 하는 연구가 활발히 진행되고 있다. 그러나, 리얼시스템사의 G2나 애플사의 QuickTime과 같은 SMIL을 지원하는 상용 플레이어들을 비롯한 기존의 다양한 SMIL 플레이어에는 SMIL 문서를 검색할 수 있는 해결책을 제시하지 못하고 있다. 현재와 같으 기하급수적인 웹의 발전은 기본적인 웹의 기능 외에 웹에 대한 다양한 검색 기능이 제공되면서부터 이며 웹의 이러한 발전 과정을 미뤄볼 때 SMIL 또한 이러한 검색 기능의 제공은 필수적이라 할 수 있다. 그러므로, 본 논문에서는 기존의 SMIL 플레이어들이 지원하지 못했던 검색 기능을 지원하기 위해 SMIL에서 의미를 가지는 엘리먼트와 컨텐트를 가지고 인덱스를 구축하고, 또한 이를 이용하여 산재해 있는 SMIL 문서와 문서내의 미디어 객체 등에 대한 검색을 수행한 후 선별적으로 디스플레이할 수 있게 하는 검색 기능을 갖는 SMIL 플레이어를 설계 및 구현한다.

• Journal of Pharmaceutical Investigation
• /
• v.22 no.1
• /
• pp.33-40
• /
• 1992

This study was aimed to control the release characteristics of ketoprofen by microencapsulating $ketoprofen-{\beta}-cyclodextrin\;(KF-{\beta}-CyD)$ solid dispersion with Eudragit RS by the phase separation method using a nonaqueous vehicle. KF alone was also microencapsulated with Eudragit RS by the evaporation process in water phase. The results obtained showed that it was not possible to microencapsulate KF alone by phase separation in a chloroform-cyclohexane system while it was easy to microencapsulate $(KF-{\beta}-CyD)$ solid dispersion system. For the microcapsules, the release test was performed in the first fluid (pH 1.2) and the second fluid (pH 6.8) of K.P.V disintegration medium at $37^{\circ}C$. The release of KF from $(KF-{\beta}-CyD)$ solid dispersion microcapsules (1:1 core wall ratio) was more sustained than that from KF microcapsules, and followed zero-order kinetics. Especially, solid dispersion microcapsules showed pH-independent release patterns with higher wall to core ratio (1:1 w/w).

• Journal of the Korean Society of Clothing and Textiles
• /
• v.19 no.2
• /
• pp.203-215
• /
• 1995

The funning process in the symbolism of dress can be approached by the semiotics of C. S. Pierce. According to Pearce\ulcorners theory, symbiosis consists of sign, its object, and interpret ant. Especially Pierce classifies the sign into three categories; icon, index, and symbol. The icon is based on the similarity in properties and forms, and the index is based on the actual connection with their objects, while the symbol is based on the association of interpret ant. This classification method can be considered as a theoretical base for symbol of ritual dress. On the other hand, it was discussed the analyzing method of the concept of dress same (symbolic element) by introducing the isolate concept of structuralism for explaining how the symbol reveals itself. So it is discussed the several concepts of structuralism; the concept of relation syntagmatique and relation paradigmatique, the relation binaries, and the units. It would be also necessary to consider dimension of context in addition to dimension of dress itself for the dimension of total symbolic elements of ritual dress. It is proposed that the above developed dress symbol elements should be used for under\ulcornerstanding the society or culture that includes the elements by introducing the symbolic anthropology such as V. Turner's three dimensions of symbol.

• Korean Journal of Animal Reproduction
• /
• v.3 no.1
• /
• pp.56-60
• /
• 1979

This study was carried out to find the difference between the naturaly born sex rtio among 1,242 head of pigs(120 litters) at Swine Farm, Cheil Sugar Co. and B-body a, pp.arance from their semen, and to find the conception rates which were inseminated to 40 sows with sperm from the anode and cathode after electrophoresis of boar semen. In order to the electrophoretic separation, the semen was placed into the platimum loop electrodes(105 cc) at room temperature for 30 minutes with D.C. 3V. and 350${\mu}$A. constant. The sperm fluorescent staining method was performed in accordance with Bhattacharya's(1970) method. The spermatozoa were observed through a Olympus Vanox microscope(made in Japan) using exciter filter with I heat barrier HPO 120. The results obtained were summarized as follows: 1. The natural sex ratio of 1,242 piglets(120 litters) which were born at Swine Farm, Cheil Sugar Co. was 50%, and B-body a, pp.arance of its boar semen were 49.24%. 2. With electrophoretic separation, the anode and cathode attracted 65.5${\pm}$5.03% and 29.89${\pm}$4.29% of B-body bearing sperm, respectively. 3. After electrophoresis of boar sperm, they were inseminated to 40 sows with sperm from anode and cathode. The conception rate was 92.5%.