• 제목/요약/키워드: Characteristic radiation

검색결과 604건 처리시간 0.036초

조화 가진에 의한 원통형 음향 방사기의 방사 효율 특성 (The Characteristic of Radiation Efficiency from Harmonic-excited Cylindrical Radiator)

  • 김관주;최승권
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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    • pp.516-523
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    • 1998
  • Radiation efficiency of a cylindrical shell whose surface vibrates under harmonic distribution is investigated by theoretical solutions and Boundary Element Method. The vibration modes of a cylindrical shell is determined from experiment and is compared with the result of Finite Element Method. Harmonic vibration response of the cylindrical shell under the point excitation and the radiation phenomena from its response is analyzed by Finite Element Method and Boundary Element Method.

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일사량 변화에 대한 최대전력점 추종 제어의 비교 연구 (Comparison Study of Maximum Power Point Tracking Control with Changing of Radiation)

  • 최정식;고재섭;정동화
    • 전기학회논문지
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    • 제59권6호
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    • pp.1075-1082
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    • 2010
  • This paper analyzes a operating characteristic for maximum power point tracking (MPPT) of photovoltaic generation system. MPPT methods are used to maximize PV array output power by tracking maximum power point(MPP) continuously. To increase the output efficiency of PV system, it is important to have more efficient MPPT. MPPT algorithm is widely used the control method such as the perturbation and observation(PO) method, incremental conductance(IC) method and constant voltage(CV) method. In case of the radiation is changed, this paper proposes a response characteristic with MPPT control algorithms. Also, it proposes the direct for a novel MPPT control algorithm development through the analyzed data, hereby proves the effectiveness of this paper.

한국형 고속철도의 소음 방사특성에 관한 연구 (A Study on Radiation Characteristics of Noise Sources for Korean Train Express)

  • Kim, Jae-Chul;Koo, Dong-Hoe;Moon, Kyung-Ho;Lee, Jae-Eun
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 추계학술대회논문초록집
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    • pp.337.1-337
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    • 2002
  • In order to control the railway noise, the radiation characteristic of the noise during the train passage should be analyzed. Generally, the major noise sources for Korean Train Express are the rolling noise and power unit noise up to 300km/h. In this paper, we describe on a train model that is considered to be a row of point sources to calculate the radiation characteristic. The calculation results are compared with short distance measurement. (omitted)

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평면 배열 안테나를 이용한 수선 지역 형태에 적합한 빔 형성 방법에 관한 연구 (A Study on the Beam forming method suitable receive area shape using planar array antenna)

  • 이봉수;장재철;안도희
    • 한국컴퓨터정보학회논문지
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    • 제8권1호
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    • pp.90-96
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    • 2003
  • 본 논문에서는 N개의 등방성 점원을 수신 지역과 동일한 구조로 배열하고 수신 지역과 동일한 방사패턴을 갖는 배열 구조에 대하여 연구하였다. 배열된 소자 간격은 그레이팅 로브를 피하면서 최적의 특성을 얻기 위하여 반파장 등간격으로 선택하였고, 각 배열 구조의 어레이 팩터를 유도한 후, 방사패턴을 이론적으로 계산하였다. 계산된 특성으로부터 각 평면 배열 안테나의 방사패턴은 수신 지역의 구조와 유사한 빔 특성을 얻을 수 있었다.

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X-선 발생장치 정류방식에 따른 출력특성에 관한 연구

  • 나길주;백수웅;양현훈;박계춘
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 추계학술대회 논문집
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    • pp.126-126
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    • 2009
  • X-ray high-voltage generator is the most important part that can decide the radiation exposure dose affecting a patient or operator according to the characteristic. If decrease of X-ray radiation exposure dose and output characteristic of high-voltage generator is unstable, a patient or operator must be exposed to more radiation. This study measures and analyzes the exposure dose reproducibility and output characteristic according to a change of tube current on the various rectification methods of diagnostic X-ray equipment. It can find that quality bastardize and output is increased if voltage of X-ray tube is increased. Exposure dose reproducibility according to output of X-ray equipment is extremely excellent in inverter type, and is stable in order of following three-phase, a single-phase and condenser method. This study can find that the reply incidence of high-voltage generator is generated due to difference in rectification method, noise occurs in X-ray due to that, quality of an image is decreased due to that, and medical diagnosis can be failed due to that.

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단일 비아 위치를 이용한 PCB의 복사성 방사 성능 향상 (Improved Characteristic of Radiated Emission of a PCB by Using the Via-Hole Position)

  • 김리진;이재현
    • 한국전자파학회논문지
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    • 제20권12호
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    • pp.1272-1278
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    • 2009
  • 본 논문은 신호 전송용 비아가 있는 4층 PCB(Printed Circuit Boards)의 P/G(power/ground)면 사이에서 발생되는 공진을 상쇄시켜 복사성 방사(RE: Radiated Emission) 성능을 개선할 수 있는 기법을 제안하였다. 면간 공진 상쇄를 확인하기 위하여 비아가 있는 4층 PCB에서 신호 전송 선로의 전송 특성, PCB 개방 모서리를 통한 방사(radiation)와 RE 세기를 계산하고, 측정하여 제안된 기법의 타당성을 입증하였다.

상용 의학용 X-ray 필름의 특성곡선 (The Characteristic Curves of Commercial Medical X-ray Films)

  • 허훈;정연태;이재성
    • 한국인쇄학회지
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    • 제19권2호
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    • pp.12-21
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    • 2001
  • For the purpose of determining characteristics of widely used commercial medical x-ray films, which are used for obtaining the Linac-grams for radiational treatment of cancers, we placed several commercial x-ray films at a fixed distance form the linear accelerator. After varying the exposed amount of radiation step by step, we could obtain a continually increasing density image for each film whose densities were determined by microdensitometer readings. The characteristic curves of the films were obtained by plotting the densities vs. the exposed radiation amounts, and their ${\gamma}$ values were determined. These values can be used to suggest a minimum necessary amount of exposed radiation to get a useful Linac-gram. The measured ${\gamma}$ values of the characteristic curves of the Kodak-DVP/RA-1 film were 1.73 when used 6MV x-ray, 1.70 when used 15MV of intensity. For the Konica-AX film, ${\gamma}$ values were 1.29 and 1.18 respectively. The result suggests that the effective conditions for high resolution of a L-gram be 6 MV of x-ray intensity and about 3 rad of exposed dose on a Kodak-DVP/RA-1 film.

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Hot Gas Analysis of Circuit Breakers By Combining Partial Characteristic Method with Net Emission Coefficient

  • Park, Sang-Hun;Bae, Chae-Yoon;Jung, Hyun-Kyo
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • 제3B권3호
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    • pp.115-121
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    • 2003
  • This paper proposes a radiation model, which considers radiation transport as an important component in hot gas analysis. This radiation model is derived from combining the method of partial characteristics (MPC) with net emission coefficient (NEC), and it covers the drawbacks of existing models. Subsequently, using this proposed model, the arc-flow interaction in an arcing chamber can be efficiently computed. The arc is represented as an energy source term composed of ohmic heating and the radiation transport in the energy conservation equation. Ohmic heating term was computed by the electric field analysis within the conducting plasma region. Radiation transport was calculated by the proposed radiation model. Also, in this paper, radiation models were introduced and applied to the gas circuit breaker (GCB) model. Through simulation results, the efficiency of the proposed model was confirmed.

Specificity Protein 1 Expression Contributes to Bcl-w-Induced Aggressiveness in Glioblastoma Multiforme

  • Lee, Woo Sang;Kwon, Junhye;Yun, Dong Ho;Lee, Young Nam;Woo, Eun Young;Park, Myung-Jin;Lee, Jae-Seon;Han, Young-Hoon;Bae, In Hwa
    • Molecules and Cells
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    • 제37권1호
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    • pp.17-23
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    • 2014
  • We already had reported that Bcl-w promotes invasion or migration in gastric cancer cells and glioblastoma multiforme (GBM) by activating matrix metalloproteinase-2 (MMP-2) via specificity protein 1 (Sp1) or ${\beta}$-cateinin, respectively. High expression of Bcl-w also has been reported in GBM which is the most common malignant brain tumor and exhibits aggressive and invasive behavior. These reports propose that Bcl-w-induced signaling is strongly associated with aggressive characteristic of GBM. We demonstrated that Sp1 protein or mRNA expression is induced by Bcl-w using Western blotting or RT-PCR, respectively, and markedly elevated in high-grade glioma specimens compared with low-grade glioma tissues using tissue array. However, relationship between Bcl-w-related signaling and aggressive characteristic of GBM is poorly characterized. This study suggested that Bcl-w-induced Sp1 activation promoted expression of glioma stem-like cell markers, such as Musashi, Nanog, Oct4 and sox-2, as well as neurosphere formation and invasiveness, using western blotting, neurosphere formation assay, or invasion assay, culminating in their aggressive behavior. Therefore, Bcl-w-induced Sp1 activation is proposed as a putative marker for aggressiveness of GBM.