• Title/Summary/Keyword: RF

Search Result 8,570, Processing Time 0.126 seconds

Distribution and Inheritance of Trypsin Inhibitor Variant in Soybeans Grown in Korea (한국대두에서의 Trypsin Inhibitor Variant의 분포와 유전)

  • Choi, J.Y.;Chang, B.H.
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.26 no.1
    • /
    • pp.51-55
    • /
    • 1981
  • Seed proteins of 51 varieties of soybean were separated by disc electrophoresis. Nine varieties had Rf 0.79 electrophoretic band, and 42 varieties had Rf 0.83 band. The frequency for Rf 0.79 was 0.176 and the frequency for Rf 0.83 was 0.824. The F_1 seeds of crossed between Kumgangdaepp (Rf 0.79) and Uidu (Rf 0.83) possessed both bands. Analysis of 96 F_2 seeds showed a ratio of 22 : 53 : 21 (Rf 0.79 : Rf 0.79/Rf 0.83 : Rf 0.83), suggesting single gene control with two co dominant alleles.

  • PDF

Analysis of Endcap Effect for MRI Birdcage RF Coil by FDTD Method (FDTD 방법을 이용한 MRI Birdcage RF Coil의 Endcap 효과 분석)

  • Chung Sung-Taek;Park Bu-Sik;Shin Yoon-Mi;Kwak June-Sik;Cho Jong-Woon;Kim Kyoung-Nam
    • Investigative Magnetic Resonance Imaging
    • /
    • v.7 no.2
    • /
    • pp.137-143
    • /
    • 2003
  • Purpose : B1 field of birdcage RF (radiofrequency) coil that is used most for brain imaging in magnetic resonance imaging (MRI) decreases toward endring from the coil center. We investigated how much RE B1 homogeneity effect the endcap shield brings form the coil center as it towards to endcap region. Materials and Methods : We compared RF B1 field distribution by each finite difference time domain (EDTD) simulations for lowpass, highpass and hybrid birdcage RF coils. We selected the highpass birdcage RF coil that was the highest RF B1 field condition as simulation result, and studied how much RF B1 homogeneity effect was occurred when endcap shield was applied to endring area. Results : B1 field of the highpass birdcage RF coil was higher than other birdcage RF coil types as simulation result. However, the RF B1 homogeneity was lower than other coil types. RE B1 field of highpass birdcage RF coil with endcap shield is similar with RF B1 field of hybrid birdcage RF coil and the overall RE B1 homogeneity in sagittal direction was better. Conclusion In this paper, proposed method can apply improving RF B1 homogeneity of RF coil in clinical examination.

  • PDF

Basic RF Coils Used in Multi-channel RF Coil and Its B1 Field Distribution for Magnetic Resonance Imaging System (자기공명영상 촬영 장치에서 다채널 RF Coil에 이용되는 기본 구조 RF Coil의 B1 Field 분석)

  • Kim, Yong-Gwon
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.11 no.12
    • /
    • pp.4891-4895
    • /
    • 2010
  • RF coil is an important component of the Magnetic Resonance Imaging (MRI) system and the performance of RF coil is one of major factors for high SNR images. Sensitivity and RF field uniformity are parameters for evaluating RF coil performance. Since the B1 field is induced by RF coil, MR signal is strongly affected by RF coil structure and arrangement. In receiving MR signal, the RF coil sensitivity to MR Signal is also determined by the induced B1 field of RF coil. Therefore, the spatial distribution of B1 field must be verified. In this work, we performed computer simulation of the basic RF coil structures using Matlab and verified their sensitivity and uniformity through their B1 field distribution. This work will be useful for the advanced multi-channel RF coil design.

eRF1aMC and $Mg^{2+}$ Dependent Structure Switch of GTP Binding to eRF3 in Euplotes octocarinatus

  • Song, Li;Jia, Yu-Xin;Zhu, Wen-Si;Chai, Bao-Feng;Liang, Ai-Hua
    • Journal of Microbiology and Biotechnology
    • /
    • v.22 no.2
    • /
    • pp.176-183
    • /
    • 2012
  • Eukaryotic translation termination is governed by eRF1 and eRF3. eRF1 recognizes the stop codons and then hydrolyzes peptidyl-tRNA. eRF3, which facilitates the termination process, belongs to the GTPase superfamily. In this study, the effect of the MC domain of eRF1a (eRF1aMC) on the GTPase activity of eRF3 was analyzed using fluorescence spectra and high-performance liquid chromatography. The results indicated eRF1aMC promotes the GTPase activity of eRF3, which is similar to the role of eRF1a. Furthermore, the increased affinity of eRF3 for GTP induced by eRF1aMC was dependent on the concentration of $Mg^{2+}$. Changes in the secondary structure of eRF3C after binding GTP/GDP were detected by CD spectroscopy. The results revealed changes of conformation during formation of the eRF3C GTP complex that were detected in the presence of eRF1a or eRF1aMC. The conformations of the eRF3C eRF1a GTP and eRF3C eRF1aMC GTP complexes were further altered upon the addition of $Mg^{2+}$. By contrast, there was no change in the conformation of GTP bound to free eRF3C or the eRF3C eRF1aN complex. These results suggest that alterations in the conformation of GTP bound to eRF3 is dependent on eRF1a and $Mg^{2+}$, whereas the MC domain of eRF1a is responsible for the change in the conformation of GTP bound to eRF3 in Euplotes octocarinatus.

TEM Analysis of Interfaces between Cr Film Sputtered with RE Bias and Photosensitive Polyimide (RE 바이어스 스퍼터링한 Cr 박막과 감광성 폴리이미드 사이의 계면 TEM 분석)

  • 조성수;김영호
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.10 no.2
    • /
    • pp.39-47
    • /
    • 2003
  • Cr thin films were deposited on photosensitive polyimide substrates by RF bias sputtering and DC sputtering and the interfaces between Cr thin film and polyimide were observed using TEM. When the polyimide surface was in-situ RF plasma cleaned at the RF power density of 0.13-2.12 $W/cm^2$, increasing of RF power density changed the morphology of polyimide surfaces from round dig to sharp shape, and surface roughness increased by anisotropic etching. The intermixed layer-like interfaces between Cr and polyimide were observed in the RF bias sputtered specimens. This interface seems to be formed due to the RF cleaning effect; the polyimide surface was RF plasma cleaned while RF power was increased to the setting point before Cr deposition.

  • PDF

Hot electron induced degradation model of the DC and RF characteristics of RF-nMOSFET (Hot electron에 의한 RF-nMOSFET의 DC및 RF 특성 열화 모델)

  • 이병진;홍성희;유종근;전석희;박종태
    • Journal of the Korean Institute of Telematics and Electronics D
    • /
    • v.35D no.11
    • /
    • pp.62-69
    • /
    • 1998
  • The general degradation model has been applied to analyze the hot carrier induced degradation of the DC and RF characteristics of RF-nMOSFET. The degradation of cut-off frequency has been severer than the degradation of bulk MOSFET drain current. The value of the degradation rate n and the degradation parameter m for RF-nMOSFET has been equal to those for bulk MOSFET. The decrease of device degradation with the increase of fingers could be explained by the large source/drain parasitic resistance and drain saturation voltage. It has been also found that the RF performance degradation could be explained by the decrease of $g_{m}$ and $C_{gd}$ and the increase of $g_{ds}$ after stress. The degradation of the DC and RF characteristics of RF-nMOSFET could be predicted by the measurement of the substrate current.t.

  • PDF

Design and Fabrication of RF evaluation board for 900MHz (900MHz대역 수신기용 RF 특성평가보드의 설계 및 제작)

  • 이규복;박현식
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.6 no.3
    • /
    • pp.1-7
    • /
    • 1999
  • A single RF transceiver evaluation board have been developed for the purpose of application to the 900MHz band transceiver contained RF-IC chip And environment test was evaluated. The RF-IC chipset includes LNA(Low Noise Amplifier), down-conversion mixer, AGC(Automatic Gain Controller), switched capacitor filter and down sampling mixer. The RF evaluation board for the testing of chipset contained various external matching circuits, filters such as RF/IF SAW(Surface Acoustic Wave) filter and duplexer and power supply circuits. With the range of 2.7~3.3V the operated chip revealed moderate power consumption of 42mA. The chip was well operated at the receiving frequency of 925~960MHz. Measurement result is similar to general RF receiving specification of the 900MHz digital mobile phone.

  • PDF

Simulation Method for Radio-Frequency Single-Electron Transistor (RF-SET) Operation (고주파 단일전자 트랜지스터 (RF-SET) 동작의 시뮬레이션 방법)

  • Yu Yun Seop;Park Hyun-Sik
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.42 no.5
    • /
    • pp.9-14
    • /
    • 2005
  • Simulation method for a pure radio-frequency (rf) mode of reflection-type and a pure rf mode of transmission-type radio-frequency single-electron transistor (RF-SET) operation is introduced. In this method, the solutions of differential equations based on Kirchhoff's law are obtained self-consistently at frequency-domain. Also, the steady-sate single-electron transistor (SET) current model and the time-dependent SET current model are used in this method. The reflected wave of a typical reflection-type RF-SET and the transmitted wave of a typical transmission-type RF-SET are calculated, and the accuracy of our developed method including the steady-state SET current model is verified with the method introduced by reference 2. At high frequency over GHz, results of our developed method including the time-dependent SET current model are considerably different from that including the steady-state SET current model. At high frequency over GHz, an exact time-dependent SET current model is needed to analyze RF-SET operation.

RF Interference Analysis and Verification in the Synthetic Aperture Radar Satellite System (영상레이더 위성시스템 구조물의 RF 간섭특성 분석 및 검증)

  • Jang, Jae-Woong;Kim, Tae-Yoon;Lim, Seong-Bin
    • Aerospace Engineering and Technology
    • /
    • v.8 no.1
    • /
    • pp.187-196
    • /
    • 2009
  • Synthetic Aperture Radar(SAR) satellite system for broad-area imaging has RF systems including SAR radiating a high power, data link system transmitting the acquired image data from the SAR, TC&R(Telemetry, Command, and Ranging) to communicate with a ground segment to control a satellite. Each system transmits RF signal having various frequencies and radiates a high power, RS(Radiated Susceptibility) specification should be verified at an electronic unit mounted in satellite. RF interference can be happened because of non-linearity of a RF system. Therefore, we manufactured a structure model installed antennas which have a similar pattern with a real antenna, the effect by RF interference is analyzed and verified.

  • PDF

Design and Fabrication of a Broadband RF Module for 2.4GHz Band Applications (2.4GHz 대역에서의 응용을 위한 광대역 RF모듈 설계 및 제작)

  • Yang Doo-Yeong;Kang Bong-Soo
    • The Journal of the Korea Contents Association
    • /
    • v.6 no.4
    • /
    • pp.1-10
    • /
    • 2006
  • In this paper, a broadband RF module is designed and tested for 2.4GHz band applications. The RF module is composed of a low noise amplifier (LNA) with a three stage amplifier, a single ended gate mixer, matching circuits, a hairpin line band pass filter and a Chebyshev low pass filter to convert the radio frequency (RF) into the intermediate frequency (IF). The LNA has a high gain and stability, and the single ended gate mixer has a high conversion gain and wide dynamic range. In the analysis of the broadband RF module, the composite harmonic balance technique is used to analyze the operating characteristics of an RF module circuit. The RF module has a 55.2dB conversion gain with a 1.54dB low noise figure, $-120{\sim}-60dBm$ wide RF power dynamic range, -60dBm low harmonic spectrum and a good isolation factor among the RF, IF, and local oscillator (LO) ports.

  • PDF