• Journal of Korean society of Dental Hygiene
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• v.6 no.1
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• pp.1-12
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• 2006

The purpose of this study was to examine what factors determined the image of dental hygienists. The subjects in this study were 396 patients and caregivers who visited 14 dental institutes in Seoul and Gyeonggi province. After a survey was conducted, the following findings were given: 1. As for what factors had a decisive impact on the image of dental hygienists, friendliness(4.53) ranked first. 2. The image of dental hygienists was decided by five different kinds of factors, which included institutional, subjective, work-related, formal and media factors. Those factors made a 57.827% prediction of the image of dental hygienists. 3. The relationship of their general characteristics to the decisive factors of dental hygienist image was as follows: 1) By age(pE0.01), marital status(pE0.01), education(pE0.01), occupation(pE0.001), were under the significantly different influence of the formal factor(pE0.01). 2) As to the type of dental institutes they visited, the subjective factor exercised a significantly different influence on the groups(pE0.01). 3) Regarding the frequency of visiting dental institutes, the institutional and work-related factors had a significantly different impact on the groups(pE0.05). 4) Concerning the experience of the caregivers, the work-related factor exercised a significantly different influence on the groups(pE0.05). 5) As to connections between their general characteristics and the decisive factors of dental hygienist image in different areas, the subjective factor mostly had the strongest impact, and the formal factor was least influential.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.1
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• pp.41-49
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• 2011

The power plants are one of the GHG major source among the sectors of fossil fuel combustion, therefore information of its emission factors is very essential to the establishing control strategies for the greenhouse gas emissions. The $CH_4$ and $N_2O$ concentration from power plants were measured using GC-FID and GC-ECD. The results showed that $CH_4$ emission factor was 0.33 kg/TJ and $N_2O$ emission factor was 0.88 kg/TJ. The $CH_4$ and $N_2O$ emission factors developed in this study were compared with those for IPCC default value and other countries emission factors. The results showed that $CH_4$ emission factor was lower than IPCC default value and Finnish emission factor, but higher than Japanese emission factor. $N_2O$ emission factor was higher Japanese emission factor and IPCC default emission factor however lower than Finnish emission factor. More research is needed on our own emission factors of various energy-consuming facilities in order to stand on a higher position in international negotiations regarding the treaties on climate changes.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1661-1668
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• 2016

A fixed off-time controlled high power factor ac-dc LED driver is proposed in this paper, which employs a novel zero-crossing-compensation (ZCC) circuit based on a fixed off-time controlled scheme. Due to the parasitic parameters of the system, the practical waveforms have a dead region. By detecting the zero-crossing boundary, the proposed ZCC circuit compensates the control signal VCOMP within the dead region, and is invalid above this region. With further optimization of the parameters KR and Kτ of the ZCC circuit, the dead zone can be eliminated and lower THD is achieved. Finally, the chip is implemented in HHNEC 0.5μm 5V/40V HVCMOS process, and a prototype circuit, delivering 7~12W of power to several 3-W LED loads, is tested under AC input voltage ranging from 85V to 265V. The test results indicate that the average total harmonic distortion (THD) of the entire system is approximately 10%, with a minimum of 5.5%, and that the power factor is above 0.955, with a maximum of 0.999.

• Nutrition Research and Practice
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• v.12 no.4
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• pp.342-347
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• 2018

BACKGROUND/OBJECTIVES: School meals are not just meals consumed at school, they are part of the culture, education, and life experience at school. Nevertheless, few studies have revealed the influence of school meals on students' school lives. The purpose of this study was to investigate the effect of satisfaction with the school meal program on students' school happiness. SUBJECTS/METHODS: A survey conducted in December 2015 asked 2,336 students (1,062 elementary school students, 880 middle school students, and 394 high school students) about their satisfaction with the school meal program and their school happiness. Multiple regression analyses were used to examine the relation between the students' school meal satisfaction and their happiness level. RESULTS: The average level of satisfaction with school meals of elementary school students was 4.1 out of 5 points, comparatively higher than that of middle and high school students, with a significant difference between school levels (P < 0.001). In addition, school happiness, as well as overall happiness, of elementary school students was higher than that of middle and high school students (P < 0.001). The school meal operation factor (0.232, P < 0.001) had the most influence on students' school happiness, followed by the school meal environment factor (0.219, P < 0.001) and school meal quality factor (0.136, P < 0.001). Overall satisfaction (0.097, P = 0.001) and school meal hygiene factor (0.095, P = 0.001) also had significant influences on students' school happiness. CONCLUSIONS: Students' satisfaction with the school meal program was related to their school happiness. Therefore, plans to enhance students' satisfaction with a school meal program needs to be implemented, with emphasis on placing a priority on school meal operation and school environment factors, in order to improve students' level of happiness.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.9
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• pp.838-842
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• 2006

0.03Pb$(Sb_{0.5}Nb_{0.5})O_{3}-0.03Pb(Mn{1/3}Nb{2/3)O_{3}-(0.94-x)PbTiO_{3}-xPbZrO_{3}$ ceramics doped with $CeO_{2}$ were synthesized by conventional bulk ceramic processing technique. Phases analysis, microstructures and piezoelectric properties were investigated as a function of $CeO_{2}$ content (0.03, 0.05, 0.1 0.3, 0.5 and 0.7 wt%). Microstructures and phases information were characterized using a scanning electron microscope (SEM) and an X-ray diffractometer (XRD). Mechanical quality factor ($Q_{m}$) and coupling factor(kp) were obtained from the resonance measurement method. Both $Q_{m}$ and $k_{p}$ were shown to reach to the maximum at 0.1 wt% $CeO_{2}$. In order to evaluate the stability of resonance frequency and effective electromechanical coupling factor ($K_{eff}$) as a function of $CeO_{2}$, the variation of resonance and anti-resonance frequency were also measured using a high voltage frequency response analyzer under various alternating electric fields from 10 V/mm to 80 V/mm. It was shown that the stability of resonance frequency and effective electromechanical coupling factor were increased with increasing the $CeO_{2}$ contents.

• Korean Journal of Biological Psychiatry
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• v.22 no.4
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• pp.163-172
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• 2015

Objectives This study was aimed to examine the multidimensional relationship between auditory verbal hallucinations (AVHs) and Positive and Negative Syndrome Scale (PANSS) factors of psychopathology in the patients with schizophrenia. And we explored the differences between assessments to hallucination by the clinicians and patients. Methods 82 patients with schizophrenia who were assessed by the Hamilton Program for Schizophrenia Voices Questionnaire (HPSVQ), Psychotic Symptom Rating Scale-Auditory Hallucination (PSYRATS-AHS), and the PANSS were recruited. Hwang's five-factor model of PANSS, items and total scores of hallucination scales, Kim's and Haddock's factor models of hallucination were applied to examine the correlations between psychopathology and AVHs. AVH-positive patients was 50 in PANSS-HPSVQ group and 24 in PANSS-PSYRATS-AHS. These two groups were separately analyzed. Results Among the five factors of the PANSS, negative and depression/anxiety factors were correlated with the total scores of HPSVQ and PSYRATS-AHS, and positive and autistic preoccupation factors were correlated only with the total score of PSYRATS-AHS. The activation factor was correlated with none of the total scores of HPSVQ/PSYRATS-AHS. These correlation patterns of a total score of HPSVQ/PSYRATS-AHS were same in the emotional factor of HPSVQ and physical factor of PSYRATS-AHS respectively. In the items which showed significant correlations, correlation coefficients of PANSS-PSYRATS-AHS group ranged between 0.406-0.755 and those of PANSS-HPSVQ ranged between 0.283-0.420. Conclusions This study suggested that the psychopathological domains of schizophrenia were differentially correlated with AVHs and the assessment of AVHs by clinicians and patients showed substantial differences which should be integrated into the therapeutic interventions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.317-320
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• 1999

In this study, the piezoelectric ceramics PZT powder was synthesized by Wet-Dry combination method. And the flexible 1-3-0 type composites were fabricated with piezoceramic PZT and Eccogel polymer matrix embedded 3rd phase. Dielectric constant of 1-3-0 type composites was lower than that of single phase PZT ceramics. Thickness mode coupling factor k/sub t/ which was comparable with single phase PZT ceramics and mechanical quality factor Qm were about 0.65 and 6, respectively. These composites are considered as a good candidates for broad-band type transducer applications. The acoustic impedance of 1-3-0 type composites was lower than that of single phase PZT ceramics. Therefore, these composites would be better used for hydrophone applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.229-233
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• 2000

In this study, the temperature coefficient of resonant frequency($TCF_r$), dielectric and piezoelectric properties of $Pb_{1-x}Sr_x[(Sb_{1/2}Nb_{1/2})_{0.035}(Mn_{1/3}Nb_{2/3})_{0.065}(Zr_{0.49},Ti_{0.51})_{0.90}]O_3$ ceramics were investigated with the Sr substitution to Pb site. The dielectric constant was increased according to the increase of Sr substitution and electromechanical coupling factor($k_t$) also showed the highest values of 0.485 when the Sr substitution was 5 mol%. Moreover, the mechanical quality factor($Q_{mt}$) showed the highest value of 233 when the Sr substitution was 2 mol%.

• Journal of the Korean Ceramic Society
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• v.56 no.4
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• pp.399-402
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• 2019

The phase evolution, microstructure, and microwave dielectric properties of (Ba_1-xNa_x)(Mg_0.5-2xY_2xW_0.5-xTa_x)O₃ (0 ≤ x ≤ 0.05) ceramics were investigated. All compositions exhibited a 1:1 ordered perovskite structure. As the value of x increased, the dielectric constant (ε_r) exhibited a tendency to increase slightly. The quality factor reached the maximum value at x = 0.01. The temperature coefficient of resonant frequency (τ_f) increased from -19.32 ppm/℃ to -5.64 ppm/℃ in the positive direction as x increased. The dielectric constant (ε_r), quality factor (Q × f₀), and temperature coefficient of resonant frequency (τ_f) of the composition x = 0.05, i.e., (Ba_0.95Na_0.05)(Mg_0.4Y_0.1W_0.45Ta_0.05)O₃ were 19.9, 128,553 GHz, and -5.6 ppm/℃, respectively.

• Korean Journal of Acupuncture
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• v.25 no.4
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• pp.175-185
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• 2008

Objective : Acupuncture (from the Latin acus, "needle," and pungere, "to prick") is a technique of inserting and manipulating fine needles at specific points on the body. As a placebo acupuncture needle device was developed based on the visual impact of needling, it has been raised that it is useful only when acupuncture points and needling are visible to subjects. To examine the visual factor of the placebo acupuncture, the present study was aimed to compare the blinding index of the verum and placebo acupuncture between masked and unmasked situation. Methods : Thirty-six patients were randomly alloted to be stimulated with a verum or placebo acupuncture in a cross-over design. They were asked to guess a right answer whether they were stimulated with the verum or placebo acupuncture at LI4 in an unmasked or masked situation. The penetrating, pain, and deqi sensations were also measured after the stimulation using modified visual analogue scale. Results : The correct answer rate of the placebo acupuncture was 22.2% and 16.7% in an unmasked and masked situation, respectively (P>0.767). The blinding index of the placebo acupuncture was -0.56 (95%CI -0.84 to -0.27) and -0.67 (95%CI -0.91 to -0.42) in an unmasked and masked situation, respectively. The penetrating and deqi sensation of the verum acupuncture were significantly higher than those of the placebo acupuncture in both unmasked and masked situation. The pain sensation of the verum acupuncture was significantly higher than that of the placebo acupuncture in masked situation, but not in unmasked situation. Conclusion : Blinding of the placebo acupuncture was successful both in the unmasked and masked situation. These finding indicate that visual factor might not play a critical role in blinding of the placebo needle. We suggest that placebo needle would be also useful in a functional magnetic resonance imaging scan even when the subject could not see the placebo needle.