• Title/Summary/Keyword: frequency-response

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Ion Transport and High Frequency Dielectric of the Hollandite Nax$(Ti_{8-x}Cr_x)O_{16}$ (Hollandite Nax$(Ti_{8-x}Cr_x)O_{16}$의 이온 전송과 고유전율 특성)

  • Yun, Ju-Ho;Li, Ying;Choi, Yong-Sung;Lee, Kyung-Sup
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.241-242
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    • 2008
  • The Velocity Autocorrelation Function (VAF) of the sodium ions is calculated for a range of temperature from 250K to 1000K and converted into the linear ac-conductivity and ac-susceptibility response via Fourier transformation. A peak is found in the conductivity around $6\times10^{12}$ Hz that has some of the character of a Poley absorption. Here it is shown to be due to an harmonically coupled site vibrations of the sodium atoms, which extend only over a limited range. At frequencies below the peak the conductivity tends towards a constant i.e. dc value corresponding to a constant flow of ions through the simulation cell. At high temperatures the conductivity due to this ion transport process behaves like a metal with an insulator to metal transition occurring around a specific temperature.

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Seismic Analysis on Recycled Aggregate Concrete Frame Considering Strain Rate Effect

  • Wang, Changqing;Xiao, Jianzhuang;Sun, Zhenping
    • International Journal of Concrete Structures and Materials
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    • v.10 no.3
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    • pp.307-323
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    • 2016
  • The nonlinear behaviors of recycled aggregate concrete (RAC) frame structure are investigated by numerical simulation method with 3-D finite fiber elements. The dynamic characteristics and the seismic performance of the RAC frame structure are analyzed and validated with the shaking table test results. Specifically, the natural frequency and the typical responses (e.g., storey deformation, capacity curve, etc.) from Model 1 (exclusion of strain rate effect) and Model 2 (inclusion of strain rate effect) are analyzed and compared. It is revealed that Model 2 is more likely to provide a better match between the numerical simulation and the shaking table test as key attributes of seismic behaviors of the frame structure are captured by this model. For the purpose to examine how seismic behaviors of the RAC frame structure vary under different strain rates in a real seismic situation, a numerical simulation is performed by varying the strain rate. The storey displacement response and the base shear for the RAC frame structure under different strain rates are investigated and analyzed. It is implied that the structural behavior of the RAC frame structure is significantly influenced by the strain rate effect. On one hand, the storey displacements vary slightly in the trend of decreasing with the increasing strain rate. On the other hand, the base shear of the RAC frame structure under dynamic loading conditions increases with gradually increasing amplitude of the strain rate.

Enhanced Amplitude Panning for Virtual Source Imaging (가상 음원 이미징을 위한 향상된 진폭 패닝 기법)

  • Hyun, Dong-Il;Park, Young-Cheol;Youn, Dae Hee
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.3
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    • pp.139-145
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    • 2013
  • In this paper, the problems of the conventional amplitude panning method for a stereophonic panning system are analyzed. We observed that the distortion showed a feedforward comb filter response. As a remedy to this distortion, we propose a stereophonic panning system using a feedback comb filter. The comb filter is designed to minimize the difference between interaural level difference(ILD) of the proposed system and that of HRTF because ILD is most salient cue for the perception of the source direction. The proposed system is configured to operate selectively for the frequency band related to the source direction. The performance of the proposed system is verified by subjective listening tests.

Elementary School Students' Psychological Proximity of Electricity and Magnetism Concepts (전기와 자기 개념간의 근접도에 대한 초등학생의 학년별 변화)

  • 권성기;이재호
    • Journal of Korean Elementary Science Education
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    • v.23 no.3
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    • pp.199-207
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    • 2004
  • Elementary science curriculum is designed to be closely-related magnetism with electricity in a physics domain and this paper explored whether elementary school students have recognized of relationships between them and whether there are any trends in the degree of recognition by grades. The elementary students of 3rd to 6th grade (total 154 persons) in a school in a local city participated in the experiment. Two forms of questionnaire were administrated to each grades. In the first questionnaire about magnetism, students were asked to rank the physics terms as the degree of proximity into magnetism and to write briefly the reason. In the second questionnaire about electricity, students were asked to do the same routine. The closer to the central term in the diagram, the lower score were given and the terms were classified as closely related to magnetism, electricity and the rest. Calculated the response frequency and averaged by the ranked terms, it was examined that the scores of proximity in how students closely rated conception to magnetism and electricity. The result said that the upper grades students showed the degree of proximity with magnetism and electricity as closely. Therefore, the sequence of comprehension of magnetism and electricity concept, which was found in the elementary school curriculum, seems to be found in the elementary students' recognitions by grades.

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An Improved Extraction Method for Splitting Base-Collector Capacitance in Bipolar Transistor Equivalent Circuit Model (바이폴라 트랜지스터 등가회로 모델의 베이스-컬렉터 캐패시턴스 분리를 위한 개선된 추출 방법)

  • 이성현
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.41 no.7
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    • pp.7-12
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    • 2004
  • An improved extraction method considering ac current crowding effect is investigated to determine intrinsic ( $C_{\mu}$) and extrinsic ( $C_{\mu}$) base-collector capacitances of bipolar junction transistors separately. The drawbacks of conventional methods are pointed out, and the improved extraction equations are derived from a cutoff mode equivalent circuit with the ac crowding capacitance. The frequency response curves of modeled current and power gains using the extracted values of $C_{\mu}$ and $C_{\mu}$ have much better agreements with measured ones than those of the conventional methods, verifying the accuracy of the improved technique.

Unconditionally Stable Analysis of Transient Scattering from Conductors Using Time-Domain Combined Field Integral Equations (시간영역 결합적분식을 이용한 도체 과도산란의 무조건 안정된 해석)

  • 정백호;서정훈;이원우
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.40 no.8
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    • pp.340-348
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    • 2003
  • In this paper, we propose a novel formulation to solve a time-domain combined field integral equation (CFIE) for analyzing the transient electromagnetic scattering response from closed conducting bodies. Instead of the conventional marching-on in time (MOT) technique, tile solution method in this paper is based on the moment method that involves separate spatial and temporal testing procedures. Triangular patch vector functions are used for spatial expansion and testing functions for three-dimensional arbitrarily shaped closed structures. The time-domain unknown coefficient is approximated as a basis function set that is derived from tile Laguerre functions with exponentially decaying functions. These basis functions are also used as the temporal testing. Numerical results computed by the proposed method arc stable without late-time oscillations and agree well with the frequency-domain CFIE solutions.

통신위성 전력제어 및 분배장치 설계 및 해석

  • Choi, Jae-Dong
    • Aerospace Engineering and Technology
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    • v.2 no.1
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    • pp.108-116
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    • 2003
  • This research presents the design and analysis of PCDU(Power Control & Distribution Unit) of communication satellite. The PCDU of a spacecraft must provide adequate power to each subsystem and payload during mission life, and it also needs high reliability and performance in space environment. A control circuit of the PCDU include bus sensing and filter circuits, error signal amplification circuit, error compensation circuit of SAS(Shunt Assembly Switch) and BPC(Battery Power Converter). The phase margin and DC gain for the designed circuits are analyzed through the frequency response characteristics of the compensated control circuit. And also the transfer function of the battery power converter circuit are discussed at the battery CCCM(Charge Continuous Conduction Mode) and battery C/DCCM(Continuous/Discontinuous Conduction Mode).

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An Iris-coupled Partial H-plane Filter (아이리스 결합형 Partial H-plane 필터)

  • Kim Dong-Won;Lee Jeong-Hae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.2 s.93
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    • pp.128-133
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    • 2005
  • An iris-coupled partial H-plane filter as a new type of partial H-plane filter is proposed. The proposed filter can be compared with conventional H-plane filter and uses an iris-type evanescent waveguide as a coupling structure. Filter design technique based on numerical simulation is developed to design and compare the proposed filter and H-plane filter. Designed iris-coupled partial H-plane filter has the same frequency response as that of the conventional H-plane filter while its cross section is one quarter. A good agreement between measurements and theoretical prediction is achieved.

The Effect of Appearance Concern on Purchase Intention and Brand Loyalty of Cosmetics of Middle and Elderly Women (중.노년 여성의 외모관심도가 화장품 구매의도 및 브랜드 충성도에 미치는 영향)

  • Hong, Byung-Sook;Cho, You-Hyun
    • Journal of the Korean Home Economics Association
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    • v.44 no.12
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    • pp.1-7
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    • 2006
  • The purpose of this study was to analyze whether appearance concern has an effect on purchase intention and brand loyalty of cosmetics of middle and elderly women. A survey was conducted from January 20 to February 10 in 2006, among middle and elderly women. Response form the 393 subjects underwent statistical analyzes including frequency analysis, reliability analysis, factor analysis, and multiple regression analysis. First, appearance concern factors were determined to be appearance-important, appearance-care, and skin-care. Second, appearance concern factors of appearance-important and skin-care had an effect on purchase intention of cosmetics of middle and elderly women. All of appearance concern factors had an effect on brand loyalty of cosmetics of middle and elderly women. Third, purchase intention of cosmetics had an effect on brand loyalty of cosmetics of middle and elderly women. The propitiation of putting basic and colored cosmetics was high in the appearance concerned group.after controlling for main effects.

A Study on the Communication Satisfaction with Father Perceived by Adolescents - Focused on the Family Cohesion and Adaptability - (청소년기 자녀가 인지한 아버지와의 의사소통 만족에 관한 연구 - 가족의 응집성과 적응성을 중심으로-)

  • 박옥임;이경주
    • Korean Journal of Rural Living Science
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    • v.4 no.2
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    • pp.99-114
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    • 1993
  • This study is conducted to find out what differences are made on among home-environmental variables, family cohesion, adaption and communication, and to define what variables influence to communication satisfaction of adolescent children. Questionaire survey method was used. The subjects of this study were 578 male and female middle school students living in Kwangiu from July 6, 1992 to July 15, 1992. For the statistical analysis of data, frequency distribution, percentage, average, standard deviation, T-test, F-test, Pearson's correlation and regression analysis were performed. The main findings were as follows : 1) Family cohesion and adaptability variables showed significant difference according to adolescent's sea age, father's education level, income level, occupation and father's religion. 2) Communication showed significant difference according to adolescent's sex, age, father's age, education level, income level, occupation and father's religion. 3) Communication satisfaction showed significant difference about adolescent's age, father's income level. 4) Communication satisfaction showed significant difference by high level in reference to family cohesion and adaptability. 5) Communication satisfaction in reference to communication showed significant difference. 6) The most influential variable on communication satisfaction between fathers and their adolescents children was active response and marked positive influence in order family adaptability, friendly nonverbalism.

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