• Title/Summary/Keyword: Quality(0) factor

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Study on Dielectric Characteristics of Pb($Zn_{1/3}Nb_{2/3}$)$O_3$-$PbTiO_3$-$PbZrO_3$Ceramics) (Pb($Zn_{1/3}Nb_{2/3}$)$O_3$-$PbTiO_3$-$PbZrO_3$계 세라믹의 유전특성에 관한 연구)

  • 최창문;박정철;소대화
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1994.11a
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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[㏖%].

Microwave Dielectric Properties of the MST Ceramics with addition of Ce (Ce첨가에 따른 MST 세라믹스의 마이크로파 유전특성)

  • Choi, Eui-Sun;Park, In-Gil;Bae, Seon-Gi;Lee, Young-Hie
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.430-433
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    • 2001
  • The $0.96MgTiO_{3}-0.04SrTiO_{3}+xCe(x=0{\sim}1.6wt%)$ ceramics were fabricated by the conventional mixed oxide method. The sintering temperature and time were $1300^{\circ}C$, 2hr., respectively. From the X-ray diffraction patterns, it was found that the perovskite $SrTiO_{3}$ and ilmenite $MgTiO_{3}$ structures were coexisted in the $0.96MgTiO_{3}-0.04SrTiO_{3}+xCe(x=0{\sim}1.6wt%)$ ceramics. The dielectric constant$(\varepsilon_{r})$ was increased with addition of Ce. The temperature coefficient of resonant frequency$(\Gamma_{f})$ was gradually varied from positive value to the negative value with increasing the Ce. The temperature coefficient of resonant frequency of the $0.96MgTiO_{3}-0.04SrTiO_{3}+0.2Ce$ ceramics was near zero, where the dielectric constant, quality factor, and $\Gamma_{f}$ were 20.68, 50,272 and ${-0.5ppm/^{\circ}C}$, respectively.

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Microwave Dielectric Properties of the MST Ceramics with Addition of Ce (Ce첨가에 따른 MST 세라믹스의 마이크로파 유전특성)

  • 최의선;박인길;배선기;이영희
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.430-433
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    • 2001
  • The 0.96MgTiO$_3$-0.04SrTiO$_3$+xCe(x=0∼1.6 wt%) ceramics were fabricated by the conventional mixed oxide method. The sintering temperature and time were 1300$^{\circ}C$, 2hr., respectively. From the X-ray diffraction patterns, it was found that the perovskite SrTiO$_3$ and ilmenite MgTiO$_3$ structures were coexisted in the 0.96MgTiO$_3$-0.04SrTiO$_3$+xCe(x=0∼1.6 wt%) ceramics. The dielectric constant($\varepsilon$$\sub$r/) was increased with addition of Ce. The temperature coefficient of resonant frequency($\tau$$\sub$f/) was gradually varied from positive value to the negative value with increasing the Ce. The temperature coefficient of resonant frequency of the 0.96MgTiO$_3$-0.04SrTiO$_3$+0.2Ce ceramics was near zero, where the dielectric constant, quality factor, and $\tau$$\sub$f/ were 20.68, 50, 272 and -0.5pm/$^{\circ}C$, respectively.

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Microwave Dielectric Properties of $0.6TiTe_3O_8-0.4CaWO_4$ Ceramics with Sintering Temperature (소결온도에 따른 $0.6TiTe_3O_8-0.4CaWO_4$ 세라믹스의 마이크로파 유전특성)

  • Kim, Jae-Sik;Lee, Moon-Kee;Ryu, Ki-Won;Lee, Sung-Gap;Lee, Young-Hie
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.342-343
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    • 2005
  • In this study,. the microwave dielectric properties of the $0.6TiTe_3O_8-0.4CaWO_4$ ceramics with sintering temperature were investigated for LTCC application. According to the X-ray diffraction patterns, the $0.6TiTe_3O_8-0.4CaWO_4$ ceramics had columbite structure of the $TiTe_3O_8$ phase and scheelite structure of the $CaWO_4$ phase. Increasing the sintering temperature, the bulk density, the dielectric constant and the quality factor of the $0.6TiTe_3O_8-0.4CaWO_4$ ceramics were increased. In the case of the $0.6TiTe_3O_8-0.4CaWO_4$ ceramics sintered at $810^{\circ}C$, the bulk density, the dielectric constant and the quality factor were 5.72$g/cm^2$, 33.6, 22,013GHz respectively.

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Analysis of Staff Satisfaction with Staff Foodservice Quality in Hospitals (병원 직원식 서비스의 품질특성에 대한 직원만족도 분석)

  • Lee, Min-Ji;Lee, Yeon-Kyung
    • Journal of the Korean Society of Food Culture
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    • v.17 no.1
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    • pp.49-56
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    • 2002
  • The purpose of this study was to analyze staff satisfaction with staff foodservice in hospitals. The study compared the hospital staff's expectations and perceptions of foodservice. The quality satisfaction values were indicated as the differences between their expectations and perceptions. The subjects were 643 hospital staff in 11 Daegu . Kyungpook hospitals. Written questionnaires were used to collect the data. The completion rate was 76.9%. There were 17 attributes for foodservice quality, which were divided by factor analysis into four main quality factors; sensory, nutrition, sanitation and service. The high expectation and low perception items on the expectation and perception grid were: seasoning of the meals, taste of the meals, variety of the menu, nutritional considerations, cleanliness of the dishes, and prompt handling of meal complaints. On all the attributes measured, expectations were higher than perceptions. The quality satisfaction values were all negative. There were highly significant(p<0.001) correlations between quality satisfaction and variety of the menu(r=0.783), nutritional considerations(r=0.770), prompt dealing with meal complaints(r=0.762), cleanliness of meals(r=0.689), and courtesy of employees (r=0.653). There is a need to improve taste, menu variety, nutrition, sanitation, speed of handling meal complaints, and courtesy.

A Study on Quality Maintaining of Dried Red Pepper Fruits (고추의 품질보존에 대한 연구)

  • 박무현;김현구김건희
    • Food Science and Preservation
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    • v.1 no.2
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    • pp.81-86
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    • 1994
  • This study examined the quality change of red peppers during storage at various temperatures and humidities. It was observed that red peppers showed mold at aw 0.75(>25% water content), discoloration at aw 0.33(<10%) and browning at aw 0.75(>19%). The most ideal condition of the storage for red peppers was a 13∼15% water content and 60${\pm}$5% RH. The storage life for whole red peppers were 2.0 months at 40$^{\circ}C$, 13.6 months at 25$^{\circ}C$, 27.3 months at 15$^{\circ}C$, 30.0 months at 10$^{\circ}C$, and 65.0 months at -3$^{\circ}C$. During any storage period above, level of capsanthin, browning and capsaicin were changed for whole peppers. Browning appeared to be a crucial factor for marketable quality of stored red peppers. It was found that the level of capsaicin & capsanthin have a miner relationship with marketable quality for consumer. Storing red peppers in nitrogen and vacuum atmosphere packing condition was found to be better than storing them in air at various temperatures in terms of storage life and quality maintenance. The nitrogen gas packaged red peppers kept longer shelf life and better quality compared with vacuum packaging.

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Association of Sleep, Dietary Behaviors and Physical Activity with Quality of Life among Shift-work Nurses (교대근무 간호사의 수면, 식생활 행위, 신체활동이 삶의 질에 미치는 영향)

  • Lee, A-ra;Lim, Sungju;Han, Kihye
    • Journal of Korean Biological Nursing Science
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    • v.19 no.4
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    • pp.252-257
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    • 2017
  • Purpose: This study aimed to investigate the associations of sleep, dietary behaviors and physical activity with quality of life among shift-work nurses. Methods: For this cross-sectional descriptive study, data were collected from 191 shift-work nurses in a tertiary hospital. Multiple linear regression analysis was used to identify the relationships among variables. Results: The levels of sleep quality, dietary behaviors and physical activity were low. Factors associated with quality of life among shift-work nurses included sleep disturbance (B=-0.16, ${\beta}=-0.26$, p<.001), dietary behaviors (B=0.28, ${\beta}=0.24$, p<.001), and physical activity (B=0.05, ${\beta}=0.19$, p<.001). The strongest factor was sleep disturbance. Conclusion: In order to improve quality of life among shift-work nurses, it is significant to encourage and maintain health behaviors such as sleep, dietary behaviors and physical activity. Under the circumstances where shift-work cannot be avoided, personal efforts made by nurses to establish their own living standards for positive health behaviors will benefit their quality of life.

Study on Q Improvement of CMOS Spiral Inductor Using Multi Metal Layer for Silicon Substrate (실리콘 기판에서 다층 메탈을 이용한 CMOS 나선형 인덕터의 Q향상에 관한 연구)

  • 손주호;최석우;김동용
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.52 no.1
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    • pp.6-11
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    • 2003
  • The multi layer spiral inductors, which enhance the quality factor Q of an inductor fabricated on the silicon substrate, has been designed using a TSMC CMOS 0.2sum 1-poly 5-metal layer technology. To investigate the performance of the designed inductors, a 2.5-dimensional field simulation tool(Momentum) is used. The simulation results show that the quality factor Q of the 5-metal inductor is improved 1.8 times over that of a convention31 spiral inductor at 2GHz for wireless LAN applications.

Frequency Characteristics for Micro-scale SMD RE Chip Inductors of Solenoid-Type (Solenoid 형태의 초소형 SMD RF 칩 인덕터에 대한 주파수 특성)

  • Kim, Jae-Wook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.3
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    • pp.454-459
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    • 2007
  • In this work, micro-scale, high-performance solenoid-type RF chip inductors utilizing amorphous $Al_2O_3$ core material were investigated. The size of the chip inductors was $0.86{\times}0.46{\times}0.45mm^3$ and copper(Cu) wire with $27{\mu}m$ diameter was used as the coil. High frequency characteristics of the inductance(L), quality factor(Q), impedance(Z), and equivalent circuit parameters of the RE chip inductors were measured and analyzed using an RF impedance/material analyzer(HP4291B with HP16193A test fixture). It was observed that the RF chip inductors with the number of turns of 9 to 12 have the inductance of 21 to 34nH and exhibit the self-resonant frequency(SRF) of 5.7 to 3.7GHz. The SRF of inductors decreases with increasing the inductance and inductors have the quality factor of 38 to 49 in the frequency range of 900MHz to 1,7GHz.

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A Study on the Foodservice Quality of Japanese Restaurants using the Importance-Performance Analysis (IPA) (중요도-만족도 분석을 활용한 일식 레스토랑의 품질특성에 관한 연구)

  • Sohn, Jeong-Min;Kim, Hak-Seon
    • Culinary science and hospitality research
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    • v.20 no.2
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    • pp.199-213
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    • 2014
  • Japanese restaurant owners seek to secure their competitive advantage by implementing a unique competition strategy that may overcome hostile environment. Brand power, aggressive expansion and the partnership strategy with other businesses may be suggested. The present study is to find out the competitive advantages of Japanese restaurants, to compare the importance and satisfaction by different customer factors of choices and then, to identify what kinds of factors affect customer satisfaction. Total 205 copies of questionnaire, out of 230 distributed, were used for analyses. Cronbarch's alpha coefficient of all 20 items was 0.911. In terms of importance, Cronbarch's alpha coefficients were 0.887(food), 0.796(menu), 0.851(employee), 0.815(service), and 0.730(physical environment). For satisfaction, the coefficients were 0.876(food), 0.860(menu), 0.880(employee), 0.851(service), 0.730(physical environment). In addition, the exploratory factor analysis showed an acceptable factor loading, supporting 20 items' validity. The result showed that customers' perceptions of the importance of Japanese restaurant service quality was higher than their level of satisfaction in general. In particular, IPA analysis revealed that food and service factors were well operated as located in the first quadrant. However, service factor located in the second quadrant was perceived to be important yet perceived as being satisfied poorly. So this study suggests that Japanese restaurant owners should concentrate on the attributes included in this quadrant to improve the quality of foodservice. Lastly, menu and physical environment factors were located in the third quadrant showing low level of importance and satisfaction. On the basic of the IPA analysis, Japanese restaurant owners should identify their strengths and weaknesses and draw up a plan to improve service quality and to maximize their profits.