• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 추계학술대회 논문집
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• pp.13-16
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• 1994

In this paper, xPb(Zn$_{1/3}Nb_{2/3}$)$O_3$-yPbTiO$_3$-zPbZrO$_3$-(0.5wt%)MnO$_2$ ceramics were fabricated by the mixed oxide method sintered at $1250^{\circ}C$ for 2[hr] and then the deielectric, electromechanical coupling factor($K_{p}$ and mechanical coupling factor(Qm) properties were investigated. In 0.1PZN-0.45PT-0.45PZsample, dielectric properties and electromechanical coupling factor were 829 and 29%. In the case of 0.5PZN-0.45PT-0.50PZ sample, that was 101 according to mechanical quality facotr. molphotropic phase boundary(MPB) certained area which $PbTiO_3$addition quatity 40∼50[㏖%].

• 한국음향학회지
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• 제21권4호
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• pp.164-164
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• 2002

This paper proposes a hybrid method for vibration analysis in the medium to high frequency ranges using Power Flow Analysis (PFA) algorithm and Statistical Energy Analysis (SEA) coupling concepts. The main part of the developed method is the application of coupling loss factor (CLF) suggested in SEA to the power transmission, reflection coefficients in PI' A boundary conditions. The developed hybrid method shows very promising results with regard to the applications for the various damping loss factors in wide frequency ranges. And also this paper presents the applied results of Power Flow Finite Element Method (PFFEM) by forming the new joint element matrix with CLF to analyze the various plate structures in shape. The analytical results of automobile, complex plate structures show good agreement with those of PFFEM using the PFA coefficients.

• 반도체디스플레이기술학회지
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• 제17권1호
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• pp.21-26
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• 2018

In this paper, a multiple coupling inductor with expandable-integrated magnetic structure was proposed to enable miniaturization of external switched mode power supply (SMPS) for a large display. Inductance formula of the proposed inductor structure was derived through magnetic circuit analysis for a simple inductance designing process. The proposed inductor was applied into a 1kW class interleaved bridgeless power factor correction circuit which requires four inductors, and experimental steady state result of the circuit was compared. According to the experimental result, it was found that the proposed multiple coupling inductor shows the electrical characteristics that can replace the conventional separated inductors and is suitable for miniaturization of the SMPS since the circuit configuration is possible with one shared inductor.

• 한국전기전자재료학회논문지
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• 제20권1호
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• pp.31-34
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• 2007

In this study, in order to develop multilayer ceramics vibrator for ultrasonic nozzle, PMN-PNN-PZT ceramics were fabricated using $Li_{2}CO_{3}-Na_{2}_CO_{3}$ as sintering aids and their piezoelectric and dielectric characteristics were investigated according to the amount of PbO. With increasing PbO contents, secondary phases were increased and phase structure was changed from tetragonal structure to rhombohedral structure and also electromechanical coupling factor was linearly decreased. At the composition ceramics with the sintering temperature of $870^{\circ}C$ and 1 mol% excess PbO, density, electromechanical coupling factor, dielectric constant, piezoelectric d constant and mechanical quality factor showed the optimum value of $7.879\;g/cm^{3}$, 0.55, 1149, 328 pC/N, 1224, respectively for multilayer ceramics vibrator application for ultrasonic nozzle.

• 소음진동
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• 제11권2호
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• pp.257-264
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• 2001

In this research, piezoelectric smart structures are applied for SEA(Statistical Energy Analysis), which is well known approach for high frequency analysis. A new input power measurement based on piezoelectric electrical power measurement is proposed and compared with the conventional method in SEA. As an example, a simple aluminum beam on which piezoelectric actuator is attached is considered. By measuring the electrical impedance and electrical current of the piezoelectric actuator, the electrical power given on the actuator is found and this is In turn converted into the mechanical energy. From the measured value of the stored energy of the beam, the Internal loss factor is calculated and this value shows a good agreement with that given by the conventional method as well as the theoretical value. To compare the coupling loss factor, L-shape beam system which consists of a aluminum beam subsystem and a steel beam subsystem coupled by three pin is taken as second example. The input power and stored energy of each subsystem are found by the proposed approach. The coupling loss factor found by the electrical input power obtained from the piezoelectric actuator exhibits similar trend to the value found by the conventional method as well as the theoretical value. In conclusion, the use of SEA for high frequency application of piezoelectric smart structures is Possible. Especially, the input power that is essential for SEA can be found accurately by measuring the electrical input power of the piezoelectric actuator.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.959-962
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• 2001

In this study, the piezoelectric and dielectric properties and Temperature stability of resonant frequency with MnO$_2$doped 0.36Pb(Sc$_{1}$2/Nb$_{1}$2/)O$_3$- 0.25Pb(Ni$_{1}$3/Nb$_{2}$3/)O$_3$-0.39PbTiO$_3$(hereafter PSNNT) were investigated. The tetagonality of crystal structure was developed with increasing MnO$_2$additive content. With increasing MnO$_2$additive content, the electromechanical coupling factor and quality factor were increased. Electromechanical coupling k$_{p}$ and quality factor Q$_{m}$ at MnO$_2$doped with 2.0mol% were showed highest value of 55.6% and 252. In the case of specimen for MnO$_2$doped with 2mol%, temperature dependance of resonant frequency had a good properties.ies.

• 한국전기전자재료학회논문지
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• 제17권5호
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• pp.481-485
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• 2004

0.91 (PSN-PZT) －0.05BF －0.04PNW＋0.3wt%MnO$_2$＋0.6wt%CuO＋xwt%CeO$_2$ ceramics were fabricated with the variations of CeO$_2$addition at the sintering temperature of 95$0^{\circ}C$ and their microstructure, dielectric and piezoelectric characteristics were investigated. As the amount of CeO$_2$ addition increased, the grain size, density and electromechanical coupling factor(k$_{p}$) were increased and the mechanical quality factor(Q$_{m}$ ) was decreased. At the 0.3 wt% CeO$_2$, the density, grain size, electromechanical coupling factor(k$_{p}$), and pizoelectric constants(d$_{33}$, g$_{33}$) showed the maximum value of 7.87 g/㎤, 3.22 $\mu\textrm{m}$, 0.5, 289 pC/N, and 22.2 ㎷ㆍm/N, respectively. However, mechanical quality factor(Q$_{m}$ ) showed the minimum value of 807 at the 0.5 wt% CeO$_2$.$.EX>.EX>.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.269-272
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• 1999

In this study, electrical properties and TCFr of Pb(Sb$_{1}$2/Nb$_{1}$2/)O$_3$-Pb(Mn $_{1}$3/Nb$_{2}$3/)O$_3$-Pb(zr, Ti)O$_3$ composition ceramics were investigated wish the Zr/Ti ratio and the additions of Y2O3. and Fe$_2$O$_3$ Electromechanical coupling factor(Kp) showed the highest value of 0.555 in the Zr/Ti=0.50/0.50 ratio ,however, dielectric constant showed the highest value of 1,217 in the Zr/Ti = 0.49/0.51 ratio. Excellent TCFr vague of 421ppm/$^{\circ}C$] at-30~9O$^{\circ}C$ was appeared in the Zr/Ti=0.50/0.50 ratio and electro-mechanical coupling factor(Kp) , mechanical quility factor(Qm) and dielectric constant was 0.496, 1,286 and 1,085 ,respectively ,in the composition ceramics of lwt%Y$_2$O$_3$ and 0.3wt%Fe$_2$O$_3$.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2007년도 춘계학술대회 학술발표 논문집 제17권 제1호
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• pp.435-439
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• 2007

This paper deals with RLS algorithm using Newton-Raphson method based adaptive forgetting factor for a passive telemetry RF sensor system in order to estimate the time variant parameter to be included in RF sensor model. For this estimation with RLS algorithm, phasor typed RF sensor system modelled with inductive coupling principle is used. Instead of applying constant forgetting factor to estimate time variant parameter, the adaptive forgetting factor based on Newton-Raphson method is applied to RLS algorithm without constant forgetting factor to be determined intuitively. Finally, we provide numerical examples to evaluate the feasibility and generality of the proposed method in this paper.

• 한국전기전자재료학회논문지
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• 제23권5호
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• pp.379-382
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• 2010

In this study, in order to develop the lead-free piezoelectric ceramics with high piezoelectric and dielectric properties, $(K_{0.5}Na_{0.5})(Nb_{0.97}Sb_{0.03})O_3$ ceramics were fabricated using a conventional mixed oxide process and their piezoelectric and dielectric characteristics were investigated according to the $K_{5.4}Cu_{1.3}Ta_{10}O_{29}$ addition. $K_{5.4}Cu_{1.3}Ta_{10}O_{29}$ addition enhanced density, electromechanical coupling factor($k_p$) piezoelectric constant $d_{33}$ and mechanical quality factor($Q_m$). At the 0.9 mol% $K_{5.4}Cu_{1.3}Ta_{10}O_{29}$ addition, density, electromechanical coupling factor($k_p$), dielectric constant(${\varepsilon}_r$) and piezoelectric constant($d_{33}$) of specimen showed the optimum values of 0.46, 471, and 148 pC/N, respectively.