• Journal of Astronomy and Space Sciences
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• 제17권1호
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• pp.33-38
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• 2000

Synchrotron emission at 408 MHz and HI column density have been used to find an evidence for the relationship between the Galactic magnetic field and the gas density. The observational data of the brightness temperature and HI column density, $T_b(408)\;and \;N_{HI}$, near the galactic plane between galactic longitudes $l=62^{circ}\;and\;l=250^{\circ}$ show a clear linear correlation of $T_b(408)=A(l,b)+B\;N_{HI}$, where A(l, b)is a background and forground radiation at the galactic coordinate. We found $(1.4{pm}0.3)10^{-21}$ for the slope B, which describes the strength of the syncrotron radiation from the HI cloud, and agrees with the value for the MIlky Way obtained by Beuermann et al. (1985). We conclude therefore that a well defined nonthermal corelates with the HI column density originating from this HI cloud.

• 수산해양기술연구
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• 제48권2호
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• pp.174-179
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• 2012

A new absorption material, cellulose sponge soaked in cement, was made for anechoic water tank and its acoustical properties were investigated by pulse methods. The sound absorption coefficient a (dB/cm) of the material was obtained in the frequency range of 40~120kHz from the echo reduction ER (dB) and insertion loss IL (dB) data. The result was averagely 1.8dB/cm higher than the sound absorption coefficient a (dB/cm) of cork-filled rubber which is one of the most effective absorption materials. The wedge (1.2~5.0cm long) type absorption tiles were made with this new material. The echo reduction ER (dB) of the absorption tile with 5.0cm wedge measured in water tank was higher than 20dB in the experimental frequency range.

• 충청수학회지
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• 제26권1호
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• pp.91-103
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• 2013

Let (D,B) be an admissible pair. Then recall that $B\;{\times}^L_HD^{{\rightarrow}{\pi}_D}_{{\leftarrow}i_D}\;D$ are bialgebra maps satisfying ${\pi}_D{\circ}i_D=I$. We have solved a converse in case D is a Hopf algebra. Let D be a Hopf algebra with antipode $S_D$ and be a left H-comodule algebra and a left H-module coalgebra over a field $k$. Let A be a bialgebra over $k$. Suppose $A^{{\rightarrow}{\pi}}_{{\leftarrow}i}D$ are bialgebra maps satisfying ${\pi}{\circ}i=I_D$. Set ${\Pi}=I_D*(i{\circ}s_D{\circ}{\pi}),B=\Pi(A)$ and $j:B{\rightarrow}A$ be the inclusion. Suppose that ${\Pi}$ is an algebra map. We show that (D,B) is an admissible pair and $B^{\leftarrow{\Pi}}_{\rightarrow{j}}A^{\rightarrow{\pi}}_{\leftarrow{i}}D$ is an admissible mapping system and that the generalized biproduct bialgebra $B{\times}^L_HD$ is isomorphic to A as bialgebras.

• 환경위생공학
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• 제5권1호
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• pp.54-62
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• 1990

충청북도 일원에서 1976년부터 1981년사이에 산불이 발생한 산화적지와 그에 인접한 비산화지의 식생과 토양성분을 조사하여, 산화 후의 식생회복과 토양성분과의 관계를 분석한 결과는 다음과 같다. 1. 79-B의 우점종 순위가 억새-산거울-싸리의 순으로 비산화지와 같게 나타나 산화 후 2년째 회복되었고, 그 후 산화적지에서 싸리가 점차 우점종으로 발달하여 산화 후 5년이 지난 76-B의 우점종 순위가 싸리-산거울-억새의 순이었다. 2. 생활형 조성은 산화 후 2년째부터 조사지소에 따라 H-e-$D_1-R_5$ 또는 Ph-e-$D_1-R_5$로 산화적지와 비산화지가 같게 되어, 산화 후 2년째에 산화적지의 생활형이 회복되었다. 3. 천이도는 81-B의 DS=423, 81-U의 DS=524로 산화적지가 낮았으나, 산화 후 2년째인 79-B의 DS=510, 79-U의 DS=520으로 거의 같았고, 산화 후 3년째부터는 산화적지가 비산화지보다 점차 높게 나타나 산화적지는 비산화지보다 천이가 빠르게 진행됨을 알 수 있다. 4. Shannon-Wiener function, Morishita's index 및 Simpson's index 등 종 다양성의 분석 결과에 의하면, 산화 당년에는 복잡한 군집이었으나 산화 후 2~3년째에 비산화지와 같은 단순한 군집으로 회복되었다. 또한 Evenness index의 분석 결과, 산화 당년에 식물종수가 비산화지보다 많았으나 산화 후 2년째부터 비산화지와 같은 종수가 되었다. 6. 산화적지의 식생은 산화 후 2~3년째에 비산화지의 식생과 거의 같게 회복되었고, 토양성분도 2~3년째에 회복되었다. 따라서, 산화 후 식생회복 과정과 토양성분의 변화사이에는 밀접한 관련이 있었다.

• 한국전자파학회논문지
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• 제24권3호
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• pp.270-277
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• 2013

본 논문에서는 초고주파 대역에서 활용 가능한 ridge 기판 집적 도파관(RSIW:Ridge Substrate Integrated Waveguide)과 기판 집적 도파관(SIW: Substrate Integrated Waveguide) 간의 전이 구조를 제안한다. 제안된 전이 구조는 일정한 간격으로 도통 비아를 삽입하여 임피던스 정합과 전계 정합을 하였으며, 광대역 정합 특성을 갖는다. 측정 결과에서 20 dB 이하의 반사 손실 대역이 9.21~12.41 GHz이고, 중심 주파수 11 GHz 기준으로 비대역폭이 29.1 %임을 확인하였다. 또한, 가용 대역폭에서 급전 선로 부분을 제외한 전이 구조만의 삽입 손실은 최대 0.49 dB이다.

• Journal of Astronomy and Space Sciences
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• 제32권4호
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• pp.305-310
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• 2015

In this study, we examined a morningside Pi2 pulsation, with a non-substorm signature, that occurred in very quiet geomagnetic conditions (Kp = 0) at 05:38 UT on December 8, 2012, using data obtained by Van Allen Probes A and B (VAP-A and VAP-B, respectively) and at a ground station. Using 1 sec resolution vector magnetic field data, we measured the X-component of the pulsation from the Abu Simbel ground station (L = 1.07, LT = UT +2 hr, where LT represents local time) in Egypt. At the time of the Pi2 event, Abu Simbel and VAP-A (L = 3.3) were in the morning sector (07:38 LT and 07:59 MLT, respectively, where MLT represents magnetic local time), and VAP-B was in the postmidnight sector (04:18 MLT and L = 5.7). VAP-A and VAP-B observed oscillations in the compressional magnetic field component (Bz), which were in close agreement with the X-component measurements of the Pi2 pulsation that were made at Abu Simbel. The oscillations observed by the satellites and on the ground were in phase. Thus, we concluded that the observed morningside Pi2 pulsation was caused by the cavity resonance mode rather than by ionospheric current systems.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권10호
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• pp.461-469
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• 2005

In this paper, a double-excitation type single sheet tester is developed to measure the magnetic characteristics of the electrical steel sheets. The developed system has the uniform magnetic field area of 20$\times$20mm$^{2}$, and can be applied to the measurement of the magnetic characteristics of the Non-oriented and Grain oriented electrical steel sheets. In the developed system, the magnetic flux density and magnetic field intensity are measured by using B-coil and H-coil, respectively. The B-coil has 1 turn search coil for each direction, and H-coil has 640 and 640 turns for rolling direction and transverse direction on the Im thickness Glass-Epoxy basement, respectively. Through experiments, it Is shown that the system can measure the magnetic characteristics up to 1.87 of magnetic flux density in the rolling direction in case of the Grain oriented electrical steel sheet. The measured results are compared with those measured in Okayama university, .Japan.

• E2M - 전기 전자와 첨단 소재
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• 제8권3호
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• pp.267-271
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• 1995

The electrical properties of (S $r_{0.50}$P $b_{0.25}$B $a_{0.25}$)Ti $O_{3}$ ceramics were studied. Specimens were prepared by the conventional mixed oxide method, and fired between 1300[.deg. C] - 1375[.deg. C], for 2[hr.]. The electrical and structural preperties of specimens were investigated with sintering temperature. Increasing the sintering temperature from 1300[.deg. C] to 1375[.deg. C], average grain size was increased from 2.61[.mu.m] to 4.53[.mu.m]. (S $r_{0.50}$P $b_{0.25}$B $a_{0.25}$)Ti $O_{3}$ specimen sintered at 1350[.deg. C] for two hours showed good dielectric constant(2147) and dielectric loss(1.7[%]) properties at 1[khz]. Sintered density and breakdown field strength were the highest value of 5.75[g/c $m^{3}$], 20[kV/cm], respectively. Dielectric properties with applied voltage were independent of the sintering temperature.temperature.

• The Plant Pathology Journal
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• 제24권1호
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• pp.58-62
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• 2008

Utilization of carbon sources by Bacillus cereus D324, a biological control agent, and Pythium species, which causes rice seedling disease, was studied with the objective of increasing the efficacy of biological control by providing the biological control agent with specific beneficial carbon sources. D-galactose, D-sorbitol, and D-mannitol were poor carbon sources for Pythium spp. growth but were good for B. cereus D324 growth. Growth in a growth chamber of rice seeds coated with B. cereus D324 amended with specific carbon sources, such as D-galactose and D-sorbitol, showed significantly enhanced seedling emergence compared to seeds coated only with B. cereus D324. Field trials showed that both seedling emergence and yield increased, when the above specific carbon sources were added to B. cereus D324 in seed coating formulations. This result indicated that amending seed coating formulations with specific carbon sources could significantly increase seedling emergence and yield in the field.

• 한국전자파학회논문지
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• 제10권6호
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• pp.866-878
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• 1999

본 논문에서는 원형 디스크와 두 개의 환 디스크로 구성된 페라이트 공진기를 갖는 스트럽라인 서률레이 터를 설계하고 제작한다. 순환 그런함수 가법을 이용하여 각 단자의 전자계를 구하고 입력 임피던스와 산란 행렬을 유도한다. 페라이트 공진기의 각 디스크에 대한 매질 배치에 따른 서율레이션 특성, 바이어스 필드의 세기에 따른 서률레이션 특성과 포트 단자의 폭에 따른 서률레이션 특성을 비교. 분석한다. 설계된 제원을 사용하여 제작한 서률레이터의 통과대역 주파수는 1.55 GHz에서 2.95 G Hz까지이고 입력 단의 반사계수 $S_{11}$ 은 공진접 2.38 GHz에서 30 dB, 아이솔레이션 단에서 입력 단으로의 전송계수 $S_{21}$은 - 28 dB로 나타났다