• Title/Summary/Keyword: Three Rs

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Hydrothermal Precipitation of PZT Powder (PZT분말의 수열합성에 관한 연구)

  • 이경희;이병하;대문정기;천하희흥지;강원호;박한수
    • Journal of the Korean Ceramic Society
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    • v.24 no.4
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    • pp.397-403
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    • 1987
  • Pb(Zr0.52Ti0.48)O3 powders were prepared by hydrothermal synthesis. Using soluble salts such as Pb(NO3)2, TiCl4 and ZrOCl2$.$8H2O and oxide such as PbO and TiO2 as starting materials, PZT powder was hydrothermally synthesized at the temperature range between 150$^{\circ}C$ and 200$^{\circ}C$. The result showed that reactivity by alkali was decreased in the sequence of Pb(NO3)2, TiCl4, ZrOCl2, PbO, TiO2 and ZrO2. Using the first three soluble salts, PZT powder was synthesiged at 150$^{\circ}C$ for 1hr. In PbO-TiCl4-ZrOCl2 system, PZT powder was synthesized at 150$^{\circ}C$ for 8rs. In Pb(NO3)2-TiO2-ZrOCl2 system, PZT powder was synthesized at 150$^{\circ}C$ for 16hrs, in PbO-TiO2-ZrOCl2 system, the powder was synthesized at 200$^{\circ}C$ for 8hrs.

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A study on Development of 300m Class Underwater ROV (300m급 수중ROV 개발에 관한 연구)

  • 이종식;이판묵;홍석원
    • Journal of Ocean Engineering and Technology
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    • v.8 no.1
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    • pp.50-61
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    • 1994
  • A 300 meter class ROV(CROV300) is composed of three parts : a surface unit, a tether cable and an underwater vehicle. The vehicle controller is based on two processors : an Intel 8097-16-bit one chip micro-processor and a Texas Instruments TMS320E25 digital signal processor. In this paper, the surface controller, the vehicle controller and peripheral devices interfaced with the processors are described. These controllers transmit/receive measured status data and control commands through RS422 serial communication. Depth, heading, trimming, camera tilting, and leakage signals are acquired through the embedded AD converters of the 8097. On the other hand, altitude of ROV and lbstacle avoidance signals are processed by the DSP processor and periodically fetched by the 8097. The processor is interfaced with a 4-channel 12-bit D/A converter to generate control signals for DC motors an dseveral transistors to handle the relays for on/off switching of external devices.

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Photoelectric Obsrvations of RS Canum Venaticorum

  • Lee, Yong-Sam;Jeong, Jang-Hae
    • Journal of Astronomy and Space Sciences
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    • v.1 no.1
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    • pp.55-65
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    • 1984
  • A total of 618 photoelectric observations (302 in yellow and 316 in bule) is made in 1982 at the Yonsei University Observatory. Except that of the secondary eclipse the homogeneous coverage of observations successfully secured B, V, and B-V light curves. Enhanced distortions in the light curves are appeared at the phases aroung $0.^P1$, which supports the wave-like migration period of 9.7 years(Rodono 1981). One epoch time of the primary minimum was made by combining the observations in three nights. This minimum time shows that the O-C values are still decreasing and there seems to indication of increasing. B and V light curves of the primary minimum are in strong asymmetry which show less luminous in the third and fourth contacts compared to those of the first and second ones. This asymmetry may be as a result of the reflection of the wave minimum at $0.^P1$, and B-V curve also shows asymmetry, redder at the third contact than the second one by about $0.^m04$. This color difference apperature distribution on the surface of cooler, larger component(KO IV star).

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Quantitative Structure Activity Relationship between Diazabicyclo-[4.2.0]octanes Derivatives and Nicotinic Acetylcholine Receptor Agonists

  • Kim, Eun-Ae;Jung, Kyoung-Chul;Sohn, Uy-Dong;Im, Chae-Uk
    • The Korean Journal of Physiology and Pharmacology
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    • v.13 no.1
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    • pp.55-59
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    • 2009
  • Three dimensional quantitative structure activity relationship between diazabicyclo[4.2.0]octanes and nicotinic acetylcholine receptor($h{\alpha}4{\beta}2$ and $h{\alpha}3{\beta}4$) agonists was studied using comparative molecular field analysis(CoMFA) and comparative molecular similarity indices analysis(CoMSIA). From 11 CoMFA and CoMSIA models, CoMSIA with steric and electrostatic fields gave the best predictive models($q^2=0.926$ and 0.945, ${r^2}_{ncv}=0.983$ and 0.988). This study can be used to develop potent $h{\alpha}4{\beta}2$ receptor agonists with low activity on $h{\alpha}3{\beta}4$ subtype.

A Study on Sliding Shear(Mode II) Delamination of Woven Fabric composites for Carbody Structure (차체 구조용 섬유직물 복합재의 평면 전단(mode II) 층간분리 거동에 대한 시험적 연구)

  • Kim, Seung-Chul;Kim, Jung-Seok;Yoon, Hyuk-Jin;Seo, Sung-Il
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.557-563
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    • 2010
  • Mode II interlaminar fracture toughness was measured and fractured surfaces were observed of carbon/epoxy and glass/epoxy woven fabric composites for carbody structure. Woven fabric carbon/epoxy and glass/epoxy composites that made with prepreg and epoxy resin(RS1222) are used in carbody structure of Korean tilting train(TTX) and low floor bus. ENF(End Notched Flexure) specimens having $120mm{\times}20m{\times}5mm$ shape and 35mm initial crack were made with each composites and three point bending tests according to ASTM D790 were conducted for these specimens. Crack lengths in tests were recorded using optical microscope and digital camcorder. NL(Non Linear), 5% offset and Max. load points in load -displacement curves were checked and mode II interlaminar fracture toughness of these points were calculated and compared. Fractured surfaces of specimens were observed using optical microscope and mode II delamination behavior of each composites was discussed.

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Design of A Driving Circuit for Plasma Display Panels (플라즈마 디스플레이 패널 구동회로의 설계)

  • Choi, Ill-Hoon;Kim, Jun-Hyung;Lim, Beong-Ha;Yu, Sang-Dae
    • Proceedings of the KIEE Conference
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    • 2002.11c
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    • pp.554-557
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    • 2002
  • In this paper, PDP driving circuit is designed to show the pattern of still-image with ADS (Address Display Separation) driving method. The designed circuits consist of three stages which are the image processing program, digital logic parts, and power circuits. The Image processing program is designed serial-communication with RS-232C using BASIC language. Digital logic parts design ADS driving signals with Xilinx FPGA and are simulated by ModelSim 5.5f. Power circuits convert output of digital logic parts into high voltage which panel is drived.

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Performance Evaluation Study of Digital Watthour Meter using RTDS (RTDS를 이용한 Digital 적산전력량계의 성능 평가연구)

  • Kang, Min-Kyu;Park, Seok-Hoon;Kim, Woo-Hyun;Seong, Ki-Chul;Yu, In-Keun
    • Proceedings of the KIEE Conference
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    • 1999.11b
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    • pp.163-165
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    • 1999
  • This work presents the performance characteristic of digital watthour meter under the harmonics of voltage and current. Each waveform involved is different in magnitude phase, and THD(Total Harmonic Distortion). It is possible to generate harmonics and control those waveforms using RTDS(Real Time Digital Simulator). Tests were performed on a selected sample of three-phase digital watthour meter which is coupled with data acquisition system via RS 485/232 converter. The percentage error rate of the watthour meter is compared for both sinusoidal and nonsinusoidal cases and the results are given.

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Preliminary Design of Electric Interface It Software Protocol of MSC(Multi-Spectral Camera) on KOMPSAT-II (다목적실용위성 2호 고해상도 카메라 시스템의 전기적 인터페이스 및 소프트웨어 프로토콜 예비 설계)

  • 허행팔;용상순
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.101-101
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    • 2000
  • MSC(Multispectral Camera), which will be a unique payload on KOMPSAT-II, is designed to collect panchromatic and multi-spectral imagery with a ground sample distance of 1m and a swath width of 15km at 685km altitude in sun-synchronous orbit. The instrument is designed to have an orbit operation duty cycle of 20% over the mission life time of 3 years. MSC electronics consists of three main subsystems; PMU(Payload Management Unit), CEU(Camera Electronics Unit) and PDTS(Payload Data Transmission Subsystem). PMU performs all the interface between spacecraft and MSC, and manages all the other subsystems by sending commands to them and receiving telemetry from them with software protocol through RS-422 interface. CEU controls FPA(Focal Plane Assembly) which contains TDI(Timc Delay Integration) CCD(Charge Coupled Device) and its clock drivers. PMU provides a Master Clock to synchronize panchromatic and multispectral camera. PDTS performs compression, storage and encryption of image data and transmits them to the ground station through x-band.

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UBV Light Curves of AR Lacertae During 1980-'81 and 1981-'82

  • Nha, Il-Seong;Park, Hong-Suh;Kang, Young-Woon;Wood, Frank-Bradshaw;Williamon, Richard-M.;Leviton, Douglas-B.
    • Journal of Astronomy and Space Sciences
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    • v.2 no.2
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    • pp.69-99
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    • 1985
  • The UBV observations of the Brightest RS CVn-type eclipsing binary star AR Lac were made at four observatories, two in Korean and two in the U.S. in the 1980-81 and 1981-82 seasons. As a result of the cooperation, two light curves in the yellow and in the blue were completed for each observing seasons. Ultraviolet observations were also made at three of the four observatories. The orbital period of AR Lac apparantly decreased around 1977. An analysis of our yellow light curves together with five other yellow curves available in the literature since 1975 shows that there seems no periodicity in the migration of the distortion waves. There is a gradual decrease of at least 0.m1 between 1976 and 1982 in the brightness of the cooler component if one assumes that the hotter component is constant.

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A Study on the Hierarchical Real-time Operation Control and Monitoring for an Flexible Manufacturing System (유연생산시스템의 계층구조적 실시간 운용제어 및 모니터링에 관한 연구)

  • Kim, Jong-Won
    • Journal of the Korean Society for Precision Engineering
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    • v.9 no.4
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    • pp.36-43
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    • 1992
  • This paper presents a hierarchical real-time operation control and monitoring scheme of the FMS/CIM center which has been implemented at the Automation and Systems Research Institute of Seoul National University. The hierarchical structure of the whole scheme consists of three lavers. The upper layer is in charge of on-line scheduling, computer network control, shop-floor monitoring and command generation for AGV dispatching, machining, assembly, inspection, set-up, etc. The middle layer has six modules, which are installed in the FMS host computer with the upper layer and run on the multi-tasking basis. Each module is connected to one of six cell controllers distributed in the FMS model plant and transfers operation command down to each cell controller through the Ethernet/TCP-IP local area network. The lower layer is comprised of six cell control software modules for machining cell, assembly cell, inspection cell, set-up stations. AS/RS and AGV. Each cell controller reports the status of the manufacturing facilites to the middle layer as well as ecxecuting the appropriate sequence control of the manufacturing processes.

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