• 제목/요약/키워드: URN

검색결과 250건 처리시간 0.029초

Iris 전송손실 측정값을 이용한 이중모드 협대역 도파관 채널여파기의 설계 및 제작 (Design and implementation of dual-mode narrow-band waveguide channel filter using measured iris transmission loss data)

  • 정근욱;이재현
    • 전자공학회논문지A
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    • 제32A권6호
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    • pp.19-28
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    • 1995
  • In this paper, measured iris transmission loss data and simulated data by using 3-dimension full-wave analysis S/W are presented and compared with Marcuvitz's theory. And by using measured iris data, dual-mode narrow-band channel filters can be successfully implemented. This paper shows that there is severe difference between the transmission loss of iris calculated by using Marcuvitz's equation to calculate iris dimension, if the length of slot iris is longer than .lambda./.pi., and in the long urn the response of channel filter is distorted. Experimental result shows that the characteristic response of implemented channel filter by using the iris transmission loss graph presented here matches well the design specfications. In conclusion, iris transmission loss measurement method will be very useful to design channel filter.

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THE DYNAMICS OF STELLAR WINDS: THEIR STRUCTURES AND [OIII] LINE FORMATION

  • CHA SEUNG-HOON;LEE YOUNG-JIN;CHOE SEUNG-URN
    • 천문학회지
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    • 제29권spc1호
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    • pp.253-254
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    • 1996
  • To understand the dynamical structures of stellar wind bubble, one and two-dimensional calculations has been performed. Using FCT Code with cooling effects and assuming constant mass loss rate and ambient medium density, we could divide stellar winds into the regime of slow and fast winds. The slow wind driven bubble shows initially radiative and becomes partially radiative bubble in which shocked stellar wind zone is still adiabatic. In contrast., the fast wind driven bubble shows initially fully adiabatic and becomes adiabatic bubbles with radiative outer shell. We also determine analytically the onset of thin-shell formation time in case of fast wind driven bubble with power-law energy injection and ambient density structure. We solve the line transfer problem with numerical results in order to calculate line profile of [OIII] forbidden line.

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고공 환경 엔진 시험 (Altitude Engine Test)

  • 이진근;김춘택;양수석;이대성
    • 한국추진공학회지
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    • 제9권4호
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    • pp.104-111
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    • 2005
  • 항공기용 가스터빈 엔진은 일반적으로 고고도 환경에서 작동되며 그 운용환경도 지상조건과 상당한 차이를 가지고 있다. 고공환경에서의 엔진성능을 정확히 측정하기 위해서는 이러한 운용 조건을 조성하여 성능 시험을 수행하여야 하며 이를 위해 실제 비행 시험이나 고공환경 엔진시험 설비를 이용한 모사 시험을 실시하게 된다. 본 논문에서는 한국항공우주연구원 항공추진그룹에서 운용하고 있는 고공환경 엔진시험 설비와 관련 시험 기술의 현황에 대하여 소개하고자 한다.

Sn-3.5Ag 솔더를 이용한 페리퍼럴 어레이 플립칩의 열 성능 분석

  • 이택영
    • 한국마이크로전자및패키징학회:학술대회논문집
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    • 한국마이크로전자및패키징학회 2003년도 기술심포지움 논문집
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    • pp.270-277
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    • 2003
  • Thermal performance of flip chip bonding with Sn-3.5Ag solder ball was studied. The temperature distribution was measured with IR(InfraRed) camera of 25 urn resolution. The measurement shows that most of the samples had much higher maximum temperature than average temperature. With central heater and 2.5 (W), the difference between maximum and average temperature is over $80^{\circ}C$. The distribution was influenced by the location of heater, the distance from heater to flip chip bonding, and the passivation opening of solder bumps. To reduce the maximum temperature, the bigger passivation opening, the smaller chip size, and the closer location of heater to flip chip bumps are preferrable.

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Development of the Test Instrument to Assess Students' Progress in Understanding Nature of Science: Based on AAAS Benchmarks for Science Literacy

  • Choe, Seung-Urn;Lee, Eun-Ah
    • 한국지구과학회지
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    • 제24권2호
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    • pp.93-99
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    • 2003
  • The purpose of this study was to develop a new test instrument based on AAAS Benchmarks for Science Literacy, to assess k-12 students' progress in understanding nature of science (NOS). A total of 276 items were developed including 33 items for grade k-2, 36 items for grade 3-5, 78 items for grade 6-8 and 129 items for grade 9-12 and they were reviewed for validity and reliability. Key ideas that were the foundation of test items were extended, sophisticated and enriched according to the grade level. The general score of this test represents a student's cognitive state about an understanding of NOS. The result of this test can be expected to give some useful information for follow-up investigations, improving instructional design, and conducting further studies.

유기 용매 혼합비에 따른 슬러리의 유동 특성과 세라믹 그린 쉬트의 두께 제어 (Effect of Solvent Mixture Ratio on Rheology Property of Slurry and Thickness Control of Ceramic Green Sheets)

  • 김준영;김승택;박종철;유명재
    • 한국전기전자재료학회논문지
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    • 제21권3호
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    • pp.236-241
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    • 2008
  • The effect of organic solvent mixture ratio on the rheology property of slurry and thickness control of ceramic green sheet was investigated. For selecting a suitable dispersant multiple light scattering method was used to evaluate the particle migration velocity and variation of clarification layer thickness. Using the selected dispersant the dispersion property of solution according to solvent mixture ratio was investigated. Binder and plasticizers were added to formulate slurries and their viscosity was evaluated according to solvent mixture ratio. Ceramic green sheets with average thickness of 30, 50 urn were fabricated via tape casting and their thickness tolerances measured. As a result according to solvent mixture ratio the solution and slurry properties varied and for the mixture ratio of ethanol/toluene of 80/20 the ceramic green sheet with the lowest thickness tolerance was obtained.

Hand Reaching Movement Acquired through Reinforcement Learning

  • Shibata, Katsunari;Sugisaka, Masanori;Ito, Koji
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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    • pp.474-474
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    • 2000
  • This paper shows that a system with two-link arm can obtain hand reaching movement to a target object projected on a visual sensor by reinforcement learning using a layered neural network. The reinforcement signal, which is an only signal from the environment, is given to the system only when the hand reaches the target object. The neural network computes two joint torques from visual sensory signals, joint angles, and joint angular velocities considering the urn dynamics. It is known that the trajectory of the voluntary movement o( human hand reaching is almost straight, and the hand velocity changes like bell-shape. Although there are some exceptions, the properties of the trajectories obtained by the reinforcement learning are somewhat similar to the experimental result of the human hand reaching movement.

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신경신호기록용 탐침형 반도체 미세전극 어레이의 제작 (Fabrication of Depth-probe type Silicon Microelectrode array for Neural signal Recording)

  • 윤태환;황은정;신동용;김성준
    • 대한의용생체공학회:학술대회논문집
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    • 대한의용생체공학회 1998년도 추계학술대회
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    • pp.147-148
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    • 1998
  • In this paper, we developed the process for depth-probe type silicon microelectrode arrays. The process consists of four mask steps only. The steps are for defining sites, windows, and for shaping probe using plasma etch from above, and for shaping using wet etch from below, respectively. The probe thickness is controlled by dry etching, not by impurity diffusion. We used gold electrodes with a triple dielectric system consisting of oxide/nitride/oxide. The shank of the probe taper from 200um to tens of urn tip and has 30 um thickness.

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효모 발현 시스템을 이용 PAP(Pokeweed Antiviral Protein) 유전자의 세포독성 연구 (Cytotoxicity Test of Pokeweed Antiviral Protein Type I Gene by Using Yeast Expression System)

  • 김선원;박성원;강신웅;이영기;이종철;최순용;이청호
    • 한국연초학회지
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    • 제23권2호
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    • pp.133-140
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    • 2001
  • PAP-I cDNA was synthesized from total RNA of Phytolacca americana leaves by RT-PCR, and then subcloned to recombinant vector pBluescript II SK-. Using PCR with primers designed in our laboratory, we could get the 9 deletion mutant PAP-I cDNA fragments. The first of the fragments was deleted by 66bp from immature N-terminal and then the rest were deleted by 90bp sequentially. Sequentially deletion mutant PAP-I cDNAs were inserted to pAc55M, on down-stream of gall promoter. Recombinant pAc55M was transformed to yeast cells, psy1 and the cells were spreaded on SC_urn-/glucose plate media. Colonies on SC_ura-/glucose plate were streaked on the same position of SC_ura-/glucose and SC_ura-/galactose plate, and we selected colonies growing on both plates, which carry non-cytotoxic deleted mutant PAP-I cDNA. We selected 4 deletion mutant PAP-I cDNAs which have not cytotoxicity.

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FORMATION OF LINE PROFILE: SEI METHOD

  • CHOE SEUNG-URN;KANG MIN-YOUNG;KIM KYUNG-MEE
    • 천문학회지
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    • 제29권2호
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    • pp.93-105
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    • 1996
  • We have solved the radiative transfer problem using a Sobolev approximation with an escape probability method in case of the supersonic expansion of a stellar envelope to an ambient medium. The radiation from the expanding envelope turns out to produce a P-Cygni type profile. In order to investigate the morphology of the theoretical P-Cygni type profile, we have treated $V_\infty,\;V_{sto},\;\beta$ (parameters for the velocity field), it and E(parameter for collisional effect) as model parameters. We have investigated that the velocity field and the mass loss rate affect the shapes of the P-Cygni type profiles most effectively. The secondarily important factors are $V_\infty,\;V_{sto}$. The collisional effect tends to make the total flux increased but not so much in magnitude. We have infered some physical parameters of 68 Cyg, HD24912, and $\xi$ persei such as $V_\infty,\;M$ from the model calculation, which shows a good agreenment with the observational results.

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