• 음성과학
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• 제10권2호
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• pp.145-157
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• 2003

Vowels are classified by the shapes of vocal tract. These shapes form constriction points along the tract, which have an influence on such vocal tract resonance as F1, F2, F3, and so on. The formant frequency is influenced by aperture and placement of tongue and the intensity is influenced by air pressure of subglottis. The object of this study compares to characterize the spectral outputs of oral and nasal spectra for the formant frequencies and intensity of Korean oral vowels. Subjects consisted of 20 normal persons (10 male and 10 female) without laryngeal pathology. The speech sample included /a/, /e/, /i/, /o/, /u/ of Korean oral vowels. The spectrum of each vowel was analysed by Nasal View and Real Analysis Program using Dr. Speech. The result showed that nasal intensity is decreased manifestly from F1 to F2. But oral intensity and Intensity is decreased little bit from F1 to F2. The most of values of nasal formant frequency is similarity oral formant frequency and Formant frequency or little bit smaller.

• 전기학회논문지
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• 제61권12호
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• pp.1892-1897
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• 2012

Modern electronic circuits are of importance for the function of communication, traffic systems and security systems. An intentional threat to these systems could be of big casualties and economic disasters. This study has examined susceptibility of electronic circuits inside the cavity by HPEM(High Power Electromagnetics). The UWB measurements were done at an anechoic chamber using a RADAN voltage source, which can generate a transient impulse of about 200 kV. The HPEM wave penetrated inside the metal case appeared to the long damped ringwave of pulse length compared with the incident wave. In addition, the resonant frequency generated inside the metal case occurred primarily in the range of 1~3 GHz. The frequency band of 1~3 GHz was influenced on the electronic circuit, which was confirmed by an external antenna and an internal absorber. The electronic circuit was influenced by HPEM infiltrated into the cavity at the 86 kV/m out of the metal cases. Also in case of an absorber the susceptibility of an electronic circuit was smallest among other cases(aperture, antenna). It is considered that absorber has a function absorbing electromagnetic wave infiltrated into the cavity and simultaneously limiting resonance by varying a boundary condition inside the cavity. Based on the results, electronic equipment systems could be applied to protection that has suited system requirements.

• 천문학회보
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• 제37권2호
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• pp.209.2-209.2
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• 2012

UFFO Burst Alert & Trigger telescope (UBAT) is one of major instruments of UFFO-Pathfinder. The UBAT aims at 10 arcmin resolution localization of Gamma Ray Bursts with X-ray coded mask technique. It has $400mm{\times}400mm$ coded mask aperture, hopper, shielding and detector module with effective area of $191cm^2$. The detector module consists of an assembly of 36 64-ch MAPMTs and $25mm{\times}25mm$ pixellated YSO crystal array, and associated analog and digital electronics of about 2500 channels. We performed a vibration test using a dummy MAPMT with the detector module structure to measure the indused stress applied onto the MAPMT. We designed a sub-structure on the detector module to avoid the resonance that would otherwise deforms the detector module structure. A finite element analysis confirms the reduction of the load acceleration down to 12g. The experimental results are to be reported. Consequently, it proves that the MAPMT arrays of the flight UBAT detector module structure would survive in the space launch environment.

• Molecules and Cells
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• 제38권2호
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• pp.180-186
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• 2015

Escherichia coli AcrAB-TolC is a multidrug efflux pump that expels a wide range of toxic substrates. The dynamic nature of the binding or low affinity between the components has impeded elucidation of how the three components assemble in the functional state. Here, we created fusion proteins composed of AcrB, a transmembrane linker, and two copies of AcrA. The fusion protein exhibited acridine pumping activity, suggesting that the protein reflects the functional structure in vivo. To discern the assembling mode with TolC, the AcrBA fusion protein was incubated with TolC or a chimeric protein containing the TolC aperture tip region. Three-dimensional structures of the complex proteins were determined through transmission electron microscopy. The overall structure exemplifies the adaptor bridging model, wherein the funnel-like AcrA hexamer forms an intermeshing cogwheel interaction with the ${\alpha}$-barrel tip region of TolC, and a direct interaction between AcrB and TolC is not allowed. These observations provide a structural blueprint for understanding multidrug resistance in pathogenic Gram-negative bacteria.

• 한국전자파학회논문지
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• 제10권7호
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• pp.1131-1137
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• 1999

본 논문에서는 개구 결합 방식을 이용하여 단일 급전으로 이중 공진을 일으키며 공진된 면파가 서로 직교 하는 새로운 형태의 패치 안테나를 제안하였으며. 이 패치 안테나의 특성을 실험적으로 고창하였다 이를 위 해 방사소자는 새로운 형태의 두 개의 사각형 홈이 파인 정사각 패치를 사용하였고 개구 결합 구조도 패치 소자에서 발생되는 2중 편파를 수용할 수 있도록 십자형 슬롯과 90도 굽은 급전션을 사용하였다. 제안된 패 치 안테나의 특성을 이용하여 Ku 밴드 위성통신용 송수선 겸용 $2\times$ 배열 안테나를 설계 제작하였으며, 성능 분석을 통하여 위성단말기용 안테나로서의 이용 타당성을 고찰하였다. 측정된 안테나의 성능을 살펴보면 송 수신 중심주파수에서 10 dBi 이상의 이득을 얻었고, 부엽은 - 13 dB 이하, 편파 분리도는 - 17 dB 이하의 값 을 나타냈다.