• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.7
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• pp.428-432
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• 2015

Sintering and microwave dielectric properties of $Zn_{2-2x}Si_{1+x}O_4$ (x=0~0.10) ceramics were investigated. The secondary phase of ZnO was observed in the specimen for x=0 whereas $SiO_2$ was detected in that for x=0.05. The composition of $Zn_2SiO_4$ might be close to x=0.02, i.e., $Zn_{1.96}Si_{1.02}O_4$; the ratio of Zn/Si is 1.922. The insufficient grain growth was observed in the specimen of x=0. For the specimens of $x{\geq}0.05$, the grain growth sufficiently occurred through the liquid phase sintering. The value of quality factor of all specimens was dependent on the x value, i.e., the ratio of Zn/Si, whereas that of dielectric constant was independent. Relative density, dielectric constant, and quality factor ($Q{\times}f$) of the specimen for x=0.05, i.e., $Zn_{1.9}Si_{1.05}O_4$, sintered at $1,400^{\circ}C$ were 96.5%, 6.43, and 115,166 GHz, respectively.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.3
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• pp.156-156
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• 2000

The piezoelectric properties and the doping effect for $0.95Pb(Zr_xTi_{l-x})O_3+0.O5Pb(Mn_{1/3}Nb_{2/3})O_3$compositions were studied. Also, the heat generation and the change of electromechanical characteristics, the important problem in practical usage, were investigated under high electric field driving. As a experiment results under low electric field, the value of $k_p$ and ${\varepsilon}_{33}^T$ were maximized, but $Q_m$ was minimized $(k_p=0.57, Q_m=1550)$ in the composition of x=0.51. In order to increase the values of $Q_m$, $Nb_2O_5$ was used as a dopant. As the result of that, the grain size was suppressed and the uniformity of grain was improved. Also, the values of $k_p$ decreased, and the values of $Q_m$ increased with doping concentration of $Nb_2O_5$ . As a experiment results under high electric field driving, when vibration velocity was ower than 0.6[m/s], the temperature increase was 20[℃], and the change ratio of mechanical quality factor was less than 10[%]. So, its electromechanical characteristics was very stable. Conclusively, piezoelectric ceramic composition investigated at this paper is suitable for application to high power piezoelectric devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.4
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• pp.338-343
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• 2002

In this study, $Pb_{0.88}(La_{\alpha}Nd_{1-\alpha})_{0.08}(Mn_{1/3}Sb_{2/3})_{0.02}Ti_{0.98}O_3$ system ceramics with La molar ratio $\alpha$ variation were manufactured for 24 MHz class resonator application. Electromechanical coupling factor, mechanical quality factor and dynamic range of $3^{rd}$ overtone thickness vibration mode were measured as the variations of La and Nd molar ratio. Mechanical quality factor and dynamic range at $\alpha$ = 0.6 composition ceramics showed the highest value of 2691 and 52.37 dB, respectively. The temperature coefficient of resonant frequency measured from $-20^{\circ} to 80^{\circ}$ showed an excellent value of $5ppm/^{\circ}C$ at $\alpha$=1 composition ceramics.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.2
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• pp.126-130
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• 2008

In this study, in order to develop low loss multilayer piezoelectric actuator, PZN-PZT ceramics were fabricated using $Li_2CO_3,\;Bi_2O_3$, CuO and ZnO as sintering aids, their structural, piezoelectric and dielectric characteristics were investigated according to the amount of ZnO addition, At the sintering temperature of $870^{\circ}C$, the density, electromechanical coupling factor(kp), mechanical quality factor(Qm), dielectric constant(${\epsilon}_r$) and piezoelectric constant($d_{33}$) of 0.4 wt% ZnO added specimen (sintered at $870^{\circ}C$) showed the optimum value of $7.812g/cm^3$, 0.535, 916, 1399, 335 pC/N respectively. Taking into consideration above piezoelectric properties of the specimen sintered at low temperature, it was concluded that PZN-PZT ceramics using 0.4 wt% ZnO as additive showed the optimum characteristics as the composition ceramics for low loss multilayer piezoelectric actuator application.

• Journal of Korean Society for Quality Management
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• v.43 no.2
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• pp.141-150
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• 2015

Purpose: The purpose of this paper is to motivate small/medium business challenged masterpiece development and to develop masterpiece strategic system. Methods: Each checklists are developed based on WC300 (World Class 300) and MQI (Masterpiece Quality Index). Correlation between the evaluation items about MQI and WC300 is analyzed. MQI is derived associated with main improvement areas of WC300 through IPA (Importance Performance Analysis). Compliance and ranking are analyzed through HOQ (House Of Quality) using masterpiece quality main factor and limiting factor. Strategy establishment base is secured through improvement derivation and correlation analysis between MQI and GQM 4.0(Global Quality Management 4.0). Results: Detail strategy is derived considering work condition about small/medium business's three kinds of industries (machine, electric and electronic). Conclusion: It is necessary to determine the potential capacity of the current domestic small/medium businesses. Small/medium businesses should be given the opportunity to self identify and manage their strengths and improvement.

• Culinary science and hospitality research
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• v.22 no.3
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• pp.155-165
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• 2016

This study investigated general educational quality, satisfaction and loyalty related to dietary life among K university students in Busan. SPSS version 20.0 was employed to conduct various analyses, namely frequency, factor, reliability and regression. A number of results were discovered. First, factors of nutrition education quality (knowledge, interest, instructor) had a positive influence on satisfaction. Second, factors of satisfaction with nutrition education quality had a positive influence on loyalty. Third, the three factorsof nutrition education quality had a positive influence on loyalty. Of the the three nutrition education quality factors, the knowledge factor exhibited the strongest effect on satisfaction among, while the Interest factor had the strongest impacton loyalty. As a result, consideration must be given the factors that act on nutrition education quality.

• Journal of the East Asian Society of Dietary Life
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• v.12 no.4
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• pp.307-317
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• 2002

The purpose of this study was to research Koreans western food experiences and the influence of sauce on food quality. Among 1,340 respondents, 660 were males and 680 femails in Daegu and Kyeongbuk area. The first part of this study was about their experiences on western foods. As the main motivation to visit western restaurants, 33.2% responded the facilities and atmosphere and 23.7% because they liked western foods. Family was the most common group of company with 33.5% of respondents when they visited the restaurants. In terms of monthly frequency, most of them (60.7%) visited 1~2 times a month. Taste of food was the main factor (34.0%) for choosing western foods. But taste of food was also the most common dissatisfaction with western foods for 36.2% of respondents. Price of foods was next (31.6%) and quality of waiter and waitress services was the third most common factor (13.6%). The second part of the study was an investigation of the influence of sauce on food quality. 35.0% of respondents tasted the sauce at the hotel restaurant. 40.5% of respondents indicated sauce influenced the image of the western foods and 40.9% indicated the level of the influence as substantial. In total, 81.4% of respondents answered that the quality of the quality of the sauce influenced the image of the western foods. In general, the influence of sauce on western food quality was perceived as a significant contributing factor with an average 4.00 on 5-point scale in 15 questionaires. Notably, the questionnaire, "The taste of the western food is improved mostly with sauce." ranked the highest with 4.45 on the 5-point scale.int scale.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.8
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• pp.675-680
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• 2000

In this study the temperature coefficient of resonant frequency(TC $F_{r}$) dielectric and piezoelectric properties of Pb[(S $b_{1}$2//N $b_{1}$2/)$_{0.065}$)-(Z $r_{x}$, $Ti_{1-x}$ )$_{0.90}$] $O_3$ceramics were investigated with Zr/Ti ratio. The compositions near the morphotropic phase boundary (MPB) appeared when Zr/Ti ratio was 49.5/50.5 The dielectric constant and electromechanical coupling factor( $k_{p}$) also showed the highest values of 1,257, 0.653 respectively when the Zr/Ti ratio was 49.5/50.5 Moreover the mechanical quality factor( $Q_{m}$) showed th lowest value of 713 when the Zr/Ti ratio. The temperature coefficient of resonant frequency(TC $F_{r}$) abruptly change at the morphotropic phase boundary(MPB) which existed between the rhombohedral phase with highly negative TC $F_{r}$ of -106ppm/$^{\circ}C$ and the tetragonal phase with highly positive TC $F_{r}$ of +64pp $m^{\circ}C$ as Zr/Ti ratio varied from 50/50 to 49.5/50.5.50.5..50.5.

• Journal of Korean Academy of Nursing Administration
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• v.14 no.2
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• pp.176-181
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• 2008

Purpose: This study was performed to identify the relationship between patient's perceived quality of healthcare services and intention to re-visit. Method: The study subjects were 242 patients from three local clinics. The data were analyzed using SPSS PC+ 12.0 program for descriptive, Pearson's correlation coefficient, and multiple regression analysis. Result: Patients' perceived quality of healthcare services was measured 5.73$\pm$0.71 using the 7-point scale. The patients' perceived quality was moderately correlated with patient satisfaction (r=0.647, p<0.001) and intention to re-visit (r=0.604, p<0.001). Also, patient satisfaction was highly correlated with intention to re-visit (r=0.788, p<0.001). 3) the reliability factor of patients' perceived quality of healthcare services and patient satisfaction were found significant predictors of intention to re-visit. Conclusion: In conclusion, service quality evaluated by patients influenced on their intention of re-visit and especially, reliability was the most significantly influential variable.

• Journal of the Korean Ceramic Society
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• v.35 no.3
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• pp.287-293
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• 1998

The effects of B2O3 addition on the sintering behavior and th microwave dielectric properties of $(Mg_{0.93}Ca_{0.07})TiO_3$ ceramics were investigated. By addition of $B_2O_3$, increases the density of the ceramics increases and grain growth enhances, It was densified to over 94% of $(Mg_{0.93}Ca_{0.07})TiO_3$ theoretical density by the addition of 0.15-1.0wt% B2O3 and stable microwave dielectric properties observed by the addition of 0.2-0.4wt% $B_2O_3.\;(Mg_{0.93}Ca_{0.07})TiO_3$ ceramics sintered at $1200^{\circ}C$ exhibits maximum dielectric constants of 24-25 quality factor($Q{\times}f$) of more than 70000 and temperature coefficient of resonant frequency of $0\;ppm/^{\circ}C$ by adding of 0.15-0.4wt% $B_2O_3$.