• Tribology and Lubricants
• /
• v.25 no.3
• /
• pp.141-149
• /
• 2009

The effect of micro-cavities fabricated using laser surface texturing (LST) technique on polyoxymethylene (POM) surface was studied in terms of heat affected zone (HAZ), cavity geometry, surface roughness, deformation of cavity along with sliding cycles, and tribological characteristics. Cavity process parameters were lamp current, process time, and the stream of air used to minimize the flow of molten polymer into cavity. Especially, the deformation of cavity geometry was extensively studied to provide deep insight into morphological analysis of the cavities. Also, this paper presents the behavior of friction and wear of POM specimens as a function of sliding cycles.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.12 no.2
• /
• pp.133-138
• /
• 1987

In this paper the tuning characteristics of resonant frequencies are experimentally studied through the variation of the length of the inner conducting rod in a re-enterant eavity resonator. The re-enterant eavity resonator consists of a coaxial cable and a cylindrical wave guide. The length of the inner conducting rod can be varied to the longitudinal direction. The resonant frequencies of TMonq modes are measured according to the arbitrary length. In order to verify the propriety of experimental results, experimental results are compared with other theoretical results. The results in this paper can be applied to wave meter and resonant circuit of amplifier. They will be use to vary resonant frequencies of a dielectric resonator in MIC and filter.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.5
• /
• pp.223-228
• /
• 2018

In this paper the water sensor using a coaxial cavity resonator is designed and manufactured. The water sensor which can sense water drop linearly has been constructed with voltage controlled oscillator(VCO), coaxial cavity resonator, RF switch, RF detector, A/D converter, DAC and micro controller. The operating frequency range of the designed water sensor is from 2.5GHz to 3.2GHz and the input voltage and current source are 24[V/DC] and 1[A]. The designed sensor circuit includes VCO, RF switch, RF detector which varies the frequency characteristics of the devices in the high frequency of 3GHz. And so we should correct the error of the frequency characteristics of those devices in the sensor circuit. To do this, we make the reference path which switches the signals to the RF detector directly without sending it to the resonator. According to the result of simulation and measurement, we can see that there is 0-50MHz difference between simulated resonator frequency and manufactured resonator frequency.

• Journal of the Korean Ceramic Society
• /
• v.35 no.7
• /
• pp.699-705
• /
• 1998

This paper is about design of optimal structure of microstrip dielectric ceramic antenna with rectangular electrode patches in accordance with the cavity model and fabrication of its prototype sample operating at the frequency of 900 MHz. Results of this work can be employed as a useful too to develop and diversify ceramic antenna having superior performance and omni-directivity to that of current helical antenna.

• Journal of Institute of Control, Robotics and Systems
• /
• v.6 no.3
• /
• pp.309-316
• /
• 2000

A coordination method for a macro/micro robot with separate controllers is proposed and evaluated. The macro/micro robot system generally has independent controllers for the macro and the micro robot respectively. A controller for the coordination of the macro and the micro robot has been designed based on the stable independent controller of each system. The method and trajectory generation method is also proposed to track the moving desired position rapidly. The control method and trajectory generation method is also proposed to track the moving desired position rapidly. The control strategy has been implemented to the macro/micron robot system to evaluate the performance. The experimental results show that the proposed method for maintaining the micro robot within its workspace has uniform performance over the various range of the bandwidth and the proposed trajectory generator is shown to be efficient.

• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.193-197
• /
• 2008

Array of micro-dimple on polyoxymethylene (POM) surface was fabricated using Q-switched Nd:YAG laser and its characteristics were studied in terms of heat affected zone (HAZ), dimple geometry, and the effect of specimen surface roughness. Process parameters such as lamp current, process time, and the stream of air in order to minimize HAZ and flow of molten polymer into cavity were extensively studied in this work. Dimple geometry was further investigated by 3-D optical microscopy to provide deep insight into morphological analysis near the dimples. This paper also presents the applicapability of micro-dimples in polymeric tribological system, such as a thrust bearing. Micro-dimples were expected to provide low coefficient of friction and enhanced lubricity at the sliding interface.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.9B
• /
• pp.1189-1195
• /
• 2001

본 연구에서는 수평면에 대해서 양방향성을 갖고 접지면을 향해서 주빔이 25$^{\circ}$의 기울기로 지향하도록 설계된 대칭 SSAIP(Strip, Air, Inverted Patch) 구조의 슬롯 결합 back-to-back 마이크로스트립 위생배열 안테나를 설계, 제작하였다. 이 구조의 안테나는 2-섹터 셀 사이트에서 기지국 또는 중계기의 지향성 안테나에 적용할 수 있으며, 도로 환경에 따라 지향각 25$^{\circ}$를 기준으로 약 $\pm$$10^{\circ}$정도 빔을 틸트할 수 있도록 위상기와 결합된다. 안테나는 공동모델을 이용하여 해석하고 앙상블로 설계한다. IMT-2000의 상.하향 링크 주파수 범위인 1.885~2.2GHz에서 안테나를 측정한 결과 임피던스 대역폭은 약 21%이였으며, $\pm$37$^{\circ}$의 지향각 오차를 보였다.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.20 no.6
• /
• pp.33-36
• /
• 1983

This paper briefly describes the hardware side of "Development of a 16 bit computer system, " one of the national projects in which Samsung Semiconductor Telecommunication Inc. '||'&'||' KIET combined their efforts to develop a 16 bit microcomputer system based on IEEE 796 hardware bus structure. In the project CPU, memory and I/O controller boards were developed, tested and integrated into a complete system.m.

• 정보화사회
• /
• s.104
• /
• pp.28-34
• /
• 1996

다가올 초고속 정보망 시대에는 많은 부분에서 커다란 변화가 예측되고 잇다. 이러한 미래의 정보화사회에서 요구되는 효과적인 기술 개발전략을 설정하기 위해서는 미래에 대한 정확한 예측이 선결조건이라고 하겠다. 그러나 미래를 정확하게 예측하는 것은 비록 그 범위를 기술분야로 한정시킨다고 하여도 매우 어려운 일임은 주지의 사실이다. 일례로서, 1898년 미국 특허청장 듀엘은 "발명될 수 있는 것은 이미 모두 발명되었기 때문에 특허청을 폐지하자"라는 제안을 한 적이 있으며, 인텔의 공동설립자인 고든 E.무어는 마이크로 프로세서를 채용한 초기 형태의 개인용 컴퓨터 개발제의를 "개인적으로 볼때 그러한 시스템은 전혀 쓸모없다고 생각되며, 일고의 가치도 없다"라고 말한 바 있다.본 고에서는 구체적이고 상세한 기술에 대하여 논의하고자하는 것이 아니라, 향후에 전개될 초고속정보망에서의 정보기술개발의 전략적 방향과 정보기술이 가져야 할 특성의 대강에 대하여 기술하고자 한다. 먼저 새로운 패러다임 변화의 필요성 및 정보기술에서의 그 형태에 대하여 기술한 후, 새로운 패러다임에 따른 개발전략을 기술, 사업의 형태, 개발환경의 세가지 관점에서 논의한다. 그리고 초고속 정보 통신 기술이 지향하는 핵심 기술 요소 및 그 기본기술에 대하여 설명한 후, 끝으로 결론을 맺는다.

• The Science & Technology
• /
• v.33 no.5 s.372
• /
• pp.74-75
• /
• 2000

서울대 물리교육과에서 마이크로웨이브 소자에 관한 공동연구를 위해 지난 98년 12월 한국에 온 중국 과학자 Baoju Jia박사는 현재 박건식 교수팀과 함께 광대역에서 전자파를 발생하는 진행파관에 대한 연구를 계속하고 있다. 91년부터 중국전자과학기술대 교수로 재직해온 Baofu Jia박사는 "한국에서는 중국과는 달리 대부분의 연구과제가 일상생활과 밀접한 관계가 있어 연구결과를 시장에 쉽게 연결할 수 있는 장점이 있다."고 말한다.