• 대한치과보철학회지
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• 제40권6호
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• pp.572-576
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• 2002

This investigation was designed to estimate the biaxial flexure strength and fracture toughness of lithium disilicate glass-ceramics of IPS Empress 2 system pressed with as-received ingots and their sprue buttons. Two groups of the lithium disilicate glass-ceramics were prepared as follows: group 1 is ingot-pressed group; group 2 is sprue button-pressed group. A ball-on-three-ball test was used to determine biaxial flexure strength (BFS) of disks in wet environment. Scanning electron microscopy(SEM) analysis was conducted to observe the microstructure of the ceramics. Unpaired t-test showed that there were no differences in the mean biaxial Hem strength (BFS) and KIC values between group 1 and 2 (p > 0.05). Two groups showed similar values in the KIC and the strength at 5% failure probability. The SEM micrographs of the IPS Empress 2 glass-ceramic showed a closely packed, multi-directionally interlocking pattern of numerous lithium disilicate crystals protruding from the glass matrix. The lithium orthophosphate crystals could not be observed on the fracture surface etched. There was no a marked difference of the microstructure between group 1 and 2. Although there were no tests including color stability, casting accuracy, etc., the results of this study implied that we could reuse the sprue button of the pressed lithium disilicate glass-ceramic of IPS Empress 2 system.

• Structural Engineering and Mechanics
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• 제43권1호
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• pp.71-87
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• 2012

This paper extends a single equation, semi-analytical approach for three-span bridges to multi-span ones for the rapid and precise determination of natural frequencies and natural mode shapes of an orthotropic, multi-span plate. This method can be used to study the dynamic interaction between bridges and vehicles. It is based on the modal superposition method taking into account intermodal coupling to determine natural frequencies and mode shapes of a bridge deck. In this paper, a four- and a five-span orthotropic roadway bridge deck are compared in the first 10 modes with a finite element method analysis using ANSYS software. This simplified implementation matches numerical modeling within 2% in all cases. This paper verifies that applicability of a single formula approach as a simpler alternative to finite element modeling.

• 대한치과보철학회지
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• 제38권5호
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• pp.575-582
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• 2000

This investigation was designed to determine whether heat-pressing and/or simulated heat treatments affected the flexure strength and the microstructure of the lithium disilicate glass-ceramic in the IPS Empress 2 system. Four groups of the specimens were prepared as follows: group 1 - as-received material, group 2 - heat-pressed material; group 3 - heat-pressed and simulated initial heat-treated material; group 4 - heat-pressed and the simulated heat-treated material with full firings for a final restoration. The three-point bending test and the scanning elec-tron microscope (SEM) analysis was conducted for the purpose of this study. The flexure strength of group 2 was significantly higher than that of group 1. However, there were no significant differences in strength among group 2, 3, and 4, and between group 1 and 4. The SEM micrographs of the lithium disilicate glass-ceramic showed the closely packed, multi-directionally interlocking microstructure of numerous lithium disilicate crystals protruding from the glass matrix. The crystals of the heat-pressed materials (group 2, 3, and 4) were a little denser and about two times bigger than those of the as-received material (group 1). This change of microstructure is more obviously exhibited particularly between group 1 and 2. However, there was no a marked difference among group 2, 3, and 4 after the heat-pressing procedure. Although there were significant increase of the strength and some changes of the microstructure after the heat-pressing operation, the combination of the heat-pressing and the simulated subsequent heat treatments did not produce the increase of strength of IPS Empress 2 glass-ceramic.

• 융합정보논문지
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• 제7권6호
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• pp.253-258
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• 2017

이 연구는 국내 중소기업을 대상으로 사업 리스크 인지 수준이 높은 기업과 그렇지 않은 기업 간 사회적 책임(CSR) 수행 활동과 그 이행 효과에 차이가 있는지 그리고 그 차이가 어떤 경로를 거쳐 발현되는지를 분석하는 것이 목적이다. 이를 위해 분석 대상 중소기업을 리스크 지각 정도에 따라 두 집단으로 분류하고, t-검정과 구조모형을 통해 두 집단 간 경로계수를 비교하였다. 그로써 CSR 수행 활동 요인과 CSR 이행에 따른 재무성과 및 비재무성과 차이 및 그 차이의 통계적 유의미성을 검증한 결과, 두 그룹 간 CSR 활동 차이는 소통과 차별전략 변인에서 나타나는 것으로 확인되었다. 그리고 두 그룹 간 CSR 수행 효과는 재무성과에서 그 차이가 발생하고 있음을 보였다.

• The Journal of Asian Finance, Economics and Business
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• 제9권7호
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• pp.153-171
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• 2022

To measure economic performance, customer satisfaction indices are constructed. This study proposes an index for banking and telecom, a significant evaluative system for comparing and enhancing customer satisfaction across the industries. The study suggests and examines amendments and improvements to the prior indices and incorporates ignored indicators to propose a punier index for Pakistan. The study is a pioneer in integrating online and offline indices into a single comprehensive model. The study is enriched by the Theory of Reasoned Action and Technological Acceptance Model. A sample of 320 respondents was used. The sample was divided based on gender and marital status. To authenticate the theoretical model, PLS-SEM was applied. We discovered nine latent variables that define customer satisfaction and conclude that a single model can be utilized for e-commerce enterprises as well. The index scores are comparable to the American index for banking and the Turkish index for telecom. Multi-group analysis (MGA) was used to comprehend the differences among the groups. This reveals that customization, design, reliability, and responsiveness induce satisfaction in telecom male and married customers. For the banking industry, the difference exists in complaint handling, customization, corporate image, perceived price, reliability, responsiveness, sentiments, convenience, and security to satisfaction links, image and complaint handling to loyalty links.

• 한국보육지원학회지
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• 제14권2호
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• pp.39-58
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• 2018

Objective: The purpose of this study was to explore the mediating effects of parenting efficacy on the relationship between parenting alliance and parenting stress, and to investigate whether the relationships between these indicators were the same for mothers and fathers. Methods: A sample of 228 parents (114 mothers and 114 fathers) of 6 month old infants in Gyeonggi Province completed measures of Perceived Parenting Competence, Parenting Alliance Inventory, and Parenting Stress Inventory-Short Form. Results: The results indicated that parenting alliance produced its effect directly and indirectly through parenting efficacy on parenting stress. Using multiple group SEM analyses, it revealed that fathers parenting efficacy was mediated by parenting alliance and that the strength of the pathways was stronger for fathers than for mothers. Conclusion/Implications: These findings suggest that parenting alliance can improve father's parenting efficacy. The differential predictors of mother and father efficacy as well as their implications for future research are discussed.

• 유통과학연구
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• 제17권3호
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• pp.5-19
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• 2019

Purpose - The purpose of this research is to investigate the factors contributing to sustainable competitive advantage for multi-level marketing (MLM) firms in Malaysia. The selected variables in this study are company image, product innovation, leadership, distributor rewards system and distributor training system. Research design, data, and methodology - Quantitative research method is employed with collected sample size of 398 respondents using judgmental sampling technique. Normality and reliability test were performed in the first stage utilizing SPSS 22 and Confirmatory Factory Analysis (CFA) and variance analysis were obtained in the subsequent stage, following up with the overall fit of the measurement model, Structural Equation Model (SEM) using AMOS 22 with maximum likelihood estimation to assess the internal consistency, convergent validity and discriminant validity. Results - The research findings show that company image, leadership, distributor rewards system and distributor training system were supported and are factors affecting the sustainable competitive advantage of MLM companies in Malaysia. However, in this study, product innovation was not supported but this result does not depict that it is trivial and inconsequential in maintain sustainable advantage. Conclusion - Companies can build sustainable competitive advantage by focusing on these contributing factors. Several other comments and implications were brought to light and discussed in the paper.

• 지식경영연구
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• 제22권2호
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• pp.189-208
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• 2021

이 연구의 목적은 교육서비스품질(교수자서비스품질, 교육과정서비스품질)이 진로결정자기효능감과 진로결정수준 및 진로준비행동에 미치는 영향을 규명하는 것이다. 최종 유효 설문지 426부에 대해 타당성 검정 후, 측정모형분석(CFA)과 구조모형분석(SEM) 그리고 다중집단 분석(MCFA와 MSEM)을 실시하였다. 연구결과를 요약하면 다음과 같다. 첫째, 교육서비스품질(교수자서비스품질, 교육과정서비스품질)은 진로결정자기효능감에 정의 유의한 영향을 미쳤다. 둘째, 진로결정자기효능감은 진로결정수준과 진로준비행동에 정의 유의한 영향을 미쳤다. 셋째, 진로결정수준은 진로준비행동에 정의 유의한 영향을 미쳤다. 마지막으로, 신입생과 재학생의 차이는 교육서비스품질(교수자서비스품질, 교육과정서비스품질)과 진로결정자기효능감, 진로결정수준, 진로준비행동 간의 관계에 조절효과가 있는 것으로 나타났다. 본 연구는 대학생의 진로에 있어 진로결정수준과 진로준비행동의 결정요인을 파악하여 제공함으로써 대학 진로 교육 개선에 유용한 기초자료로 활용할 수 있을 것이다.

• The Journal of Advanced Prosthodontics
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• 제12권4호
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• pp.197-203
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• 2020

PURPOSE. The aim of this study was to evaluate the effect of multiple firings on the bond strength between yttriatetragonal zirconia polycrystals (Y-TZP) and 2 types of resin cements. MATERIALS AND METHODS. Sixty 3Y-TZP specimens (LAVA Frame Multi) were divided into 3 groups depending on the following firing procedures: (1) 2-firing cycles, (2) 5-firing cycles, (3) 10-firing cycles. Two samples from each group were investigated by using SEM to determine the morphological changes. All specimens were treated with 125 ㎛ airborne-particle abrasion and the surface roughness of each specimen was measured. The specimens from each firing group were then further divided into 2 subgroups (n = 9) to apply 2 types of resin cement (MDP-free resin cement: RelyX Unicem-RU, and MDP containing resin cement: Panavia F 2.0-PA). The shear bond strength (SBS) test was performed and failure types of all the debonded specimens were classified by using a stereomicroscope as adhesive, cohesive, and mixed. The statistical analysis of surface roughness and SBS data were performed by using 1-way ANOVA and 2-way ANOVA followed by Tukey-HSD tests (α=.05). Failure modes were calculated as a percentage for each group. RESULTS. The bond strength of RU and PA to the specimens obtained with 2 firings were not statistically different from each other (P=.1). However, the SBS values of PA were found to be significantly higher than RU for the specimens obtained with 5 and 10 firing cycles (P=.001 and P=.02, respectively). Surface roughness analysis revealed no statistical difference between groups (P=.2). The SEM analysis of samples fired 5- and 10- times showed irregularities and boundary loss in zirconia grains, and empty spaces between zirconia grains. CONCLUSION. The bond strength of PA cement was higher than that of RU to the zirconia subjected to repeated firings (5 and 10 firing cycles). When zirconia is subjected to multiple firings, using MDP-containing resin cement can be recommended.

• 한국환경보건학회지
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• 제41권6호
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• pp.369-379
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• 2015

Objectives: The lack of reliable information on environmental pollution and health impacts related to asbestos contamination from abandoned mines has drawn attention to the need for a community health study. This study was performed to evaluate asbestos-related health symptoms among residents near abandoned asbestos mines located in the Chungcheong Provinces. In addition, exposure assessment for asbestos is needed although the exposure to asbestos was in the past. Methods: Past exposure to asbestos among inhabitants near abandoned asbestos mines was estimated by using surface sampling of deposited dust in indoor and outdoor residences. A total of 54 participants were divided into two groups with (34 cases) and without (20 controls) diseases related to asbestos. Surface sampling of deposited dust was carried out in indoor and outdoor residences by collecting 105 samples. Deposited dust for sampling was analyzed by polarization microscope (PLM) and scanning electron microscope?energy dispersive x-ray spectrometer (SEM-EDX) to detect asbestos. Subsequently, the elements of the deposited dust with asbestos were analyzed by SEM-EDX to assess the contribution of sources such as abandoned mines, slate and soil. Results: Among the 105 samples, asbestos was detected by PLM in 29 (27.6%) sampling points, and detected by SEM in 56 (48.6%) sampling points. Asbestos in indoor residences was detected by PLM in four sampling points, and by SEM in 12 sampling points. Asbestos detection in indoor residences may be due to ventilation between indoors and outdoors, and indicates long-term exposure. The asbestos detection rate for outdoor residences in the case group was higher than that in the control group. This can be explained as the case group having had higher exposure to asbestos, and there has been continuous exposure to asbestos in the control group as well as the case group. Conclusion: Past residential asbestos exposure may be associated with asbestosis among local residents near abandoned asbestos mines. Odds ratios were calculated for asbestos detection in outdoor residence by logistic regression analysis. Odds ratio between asbestos detection and asbestosis pulmonum was 3.36 (95% CI 0.90-12.53) (p=0.072), adjusting for age, sex, smoking status and work history with multi-variable logistic regression by PLM analysis method.