• Restorative Dentistry and Endodontics
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• 제16권1호
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• pp.121-132
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• 1991

The purpose of the study was to evaluate the marginal sealing effect of composite resin inlays according to the luting techniques and compare them to the conventional direct resin filling technique. 90 cavities of class V were prepared on the buccal surface of 90 extracted molar teeth, which were divided into four groups. Cavities of control group were directly filled with Scotchbond 2 and P - 50, and those of composite resin inlay groups were luted with one of the followings: Adhesive bond followed by Adhesive cement, All bond followed by Adhesive cement, Fuji - ionomer type L All the specimens were immersed in India ink dye solution for 7 days at $37^{\circ}C$ incubator after thermocycling between $5^{\circ}C$ and $60^{\circ}C$ and longitudinally sectioned with diamond disk inot two parts All the specimens were observed at the occlusal and gingival margins and statistical analysis was performed. The results were as follows: 1. Groups filled with composite resin inlay showed less marginal leakage than the group directly filled(p<0.01). 2. There was no significant difference in marginal leakage between composite resin inlay groups luted with Adhesive bond followed by Adhesive cement and the group luted with All bond followed by Adhesive cement(p>0.05). 3. At occlusal margins, Composite resin inlay group luted with Adhesive bond followed by Adhesive cement showed less marginal leakage than the group luted with Fuii ionomer type I(p<0.01). At gingival margins, composite resin inlay group luted with All bond followed by Adhesive cement showed less marignal leakage than the group luted with Fuji ionomer type I(P<0.01).

• The Journal of Advanced Prosthodontics
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• 제5권2호
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• pp.118-125
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• 2013

PURPOSE. The purpose of this study was to evaluate the effect of the span length on the fit of zirconia framework fabricated using CAD/CAM system. MATERIALS AND METHODS. Abutments for single, 4-unit and 6-unit fixed partial prostheses were fabricated. Ten zirconia frameworks were fabricated for each group. The marginal and internal gap were presented by means of replica technique and measured by measuring microscope ($AXIO^{(R)}$, Carl Zeiss, Rochester, NY) and software (I-$solution^{(R)}$, IMT i-solution Inc., Vancouver, BC, Canada). The results were statistically analyzed by multivariate analysis test and Dunnett T3 test for post hoc test (${\alpha}$=.05). RESULTS. There were statistically significant differences at 2, 4, 7, 8 points (mesio-distal section) and b, d, e, f, g (labio-lingual section). In some marginal reference points of 6-unit group (P<.05), the marginal gap were larger than 120 ${\mu}m$. CONCLUSION. Span length of zirconia core may have an influence on marginal and internal fit. Within the limitation of this study, the increase of span length of zirconia framework of 6 or more-unit fixed partial denture may decrease the marginal and internal fit.

• 경영과학
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• 제34권3호
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• pp.1-14
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• 2017

This study empirically analyzes the impact of inventory management performance on the energy efficiency in Korean petrochemical companies. The concept of the distance function is used to define the energy efficiency and the estimation of the distance function is performed using the stochastic frontier analysis. The inventory turnover is selected as the variable indicating the inventory management performance of the company. The main results of this study are as follows. First, the inventory turnover has a positive impact on energy efficiency. Second, during the period over 2011~2015, while the gap in energy efficiency among the companies expanded, the average energy efficiency decreased. Third, the average energy efficiency in upstream process companies was greater than downstream process companies and the gap in energy efficiency among downstream process companies was greater than upstream process companies. Fourth, the average marginal effect of inventory turnover on energy efficiency increased gradually from 2011 to 2015. Finally, the average marginal effect of inventory turnover in downstream process companies was greater than upstream process companies, and the gap in the marginal effect of inventory turnover among downstream process companies was greater than upstream process companies. These results together imply the importance of inventory management in terms of energy efficiency.

• 대한전기학회논문지:전력기술부문A
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• 제52권7호
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• pp.429-436
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• 2003

This paper presents a new approach for evaluating the transmission marginal loss factors (MLFs) considering the reactive power. Generally, MLFs are represented as the sensitivity of transmission losses, which is computed from the change of the generation at reference bus by the change of the load at the arbitrary bus-i. The conventional evaluation method for MLFs uses the only H matrix, which is a part of jacobian matrix. Therefore, the MLFs computed by the existing method, don't consider the effect of the reactive power, although the transmission losses are a function of the reactive power as well as the active power. To compensate the limits of the existing method for evaluating MLFs, the power factor at the bus-i is introduced for reflecting the effect of the reactive power in the evaluation method of the MLFs. Also, MLFs calculated by the developed method are applied to energy spot markets to reflect the impacts of reactive power. This method is tested with the sample system with 5-bus, and analyzed how much MLFs have an effect on the bidding/offer price, market clearing price(MCP), and settlement in the competitive energy spot market. This paper compared the results of MLFs calculated by the existing and proposed method for the IEEE 14-bus system, and the KEPCO system.

• 수산경영론집
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• 제54권2호
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• pp.77-90
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• 2023

This study employed the Gini coefficient decomposition analysis to classify and examine fishery household income inequality according to income sources. The raw data from the Fisheries Economic Survey by the National Statistical Office were used for the analysis after equalization according to the recommended method of the OECD. In particular, the Gini coefficient was decomposed by classifying with and without public subsidies, and the contribution, correlation, and marginal effect by income source were presented.As a result of the analysis, the inequality of fishing income and non-fishing income of fishermen was worsening, and the inequality of transfer income was continuously easing. Among them, fisheries subsidies have been analyzed to have the greatest contribution to the Gini coefficient of gross income and the highest relative marginal effect, although distribution inequality has been alleviated. On the other hand, other subsidies, including public pensions, were found to have the opposite contribution, correlation, and marginal effect to fisheries subsidies. The results of this analysis showed that even within public subsidies, the contribution to income redistribution might differ depending on the nature of the subsidy. In addition, in the case of other public subsidies, it can be seen that the transition from selective welfare to universal welfare occurs.

• 대한치과보철학회지
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• 제52권2호
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• pp.90-96
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• 2014

연구 목적: 이 연구의 목적은 열가압성형기법이 금속도재관의 치경부 변연적합도에 미치는 영향을 확인하는 것이다. 연구 재료 및 방법: 실험에 앞서, 4개의 금속 주모형을 형성하였다. 각 모형은 각각chamfer, heavy chamfer, shoulder with bevel, shoulder (collarless)변연을 형성하였다. 각 변연당 10개씩의 금관을 제작하여, 총 40개를 제작하였다. Coping 단계에서, 그리고 금속도재관 완성 단계에서 주모형과 금관 사이의 변연간극은 100배율의 광학현미경 관찰을 통하여 측정되었다. Data분석은 paired t-test along with one-way ANOVA와 Duncan multiple comparison test를 이용하여 이루어졌다. 결과: 변연간극의 평균과 표준편차를 분석한 결과, 금속 코핑과 그 후 완성된 금속도재관, 모든 경우에서 변연부 간격은 임상적 허용범위 안에 있었다. Chamfer 변연 실험군의 경우 Heavy chamfer 변연 실험군에 비하여 금속도재관 완성 후 변연부 간격의 유의한 증가가 있었다. 그리고Shoulder 변연 실험군에서 도재로 처리된 변연이 Chamfer와 Shoulder변연 실험군의 금속변연에 비하여 변연부 간격이 유의하게 작게 나타났다. 결론: 열가압성형기법을 통하여 제작한 금속도재수복물의 변연적합도는 전통적인 방법으로 제작한 금속도재수복물의 변연적합도와 유의한 차이점이 없었다. 제작과정의 효율성으로, 열가압성형기법은 임상에서의 효과적인 사용법으로 고려될 수 있다.

• Journal of the Korean Data and Information Science Society
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• 제28권5호
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• pp.1109-1123
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• 2017

본 샘플은 2001년부터 2013년까지 유가증권시장 기업의 재무특성과 라이프사이클을 동시에 고려하여 현금보유수준과 현금한계가치 결정요인을 분석했다. 본 연구의 주요한 연구결과는 다음과 같다. 첫째, 유가증권기업의 평균현금보유수준은 총자산대비 5.12%로 2000년 초에 비해서 소폭 상승했지만 외국 선행연구에서처럼 대폭적인 현금증가는 관찰되지 않았다. 평균현금보유 추이는 금융위기 발발이후 2008년경 전반적으로 상승했으나, 지난 13년 동안 최종적인 현금보유는 0.76%포인터 증가에 불과했다. 둘째, 기업라이프사이클에 따라서 현금보유수준의 결정요인의 영향정도가 서로 다르고 그 중에서도 투자기회와 관련된 변수들이 차이를 나타냈다. 기업현금의 예비적 수요 및 거래적 수요는 모두 감소한 것으로 파악되었다. 셋째, 기업라이프사이클에 따라서 현금한계가치가 서로 다르게 평가되고, 전체적으로 선행연구에 비해서 한계가치가 현저히 낮게 산출되었다. 넷째, 이러한 증거들은 유가증권시장 기업들이 투자기회의 위축 등으로 현금을 축적하고자하는 유인이 감소했음을 시사한다.

• 산업융합연구
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• 제2권1호
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• pp.23-46
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• 2004

Tax exhaustion effect hypothesis says that firms with low expected marginal tax rates on their interest deductions employ less debt in their capital structure. We use logit analysis to study how financing decision is related to tax after controlling non tax effects. We treat non debt tax shields as proxy of marginal corporate tax rates which affect the probability of using the deductibility of debt tax shields and empirically test the tax effect on financing decision in Korea. In conclusion, we provide evidence that debt financing is positively related to tax in the former sub-period. This results partially support for tax exhaustion effect hypothesis and low tax rate firms have lower debt levels than high tax rate firms.

• 구강회복응용과학지
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• 제28권2호
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• pp.127-138
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• 2012

본 연구에서는 임플란트 고정체와 지대주 간의 전하중 크기가 임플란트 주위 변연골의 응력분포에 미치는 영향에 대해 조사하였다. 해석 모델은 하악골에 식립되는 단일 임플란트(solid형 지대주와 submerged 형 고정체)로 제작되었고, 외력 조건으로는 임플란트 지대주 상부에 100N의 기능력이 협설 방향으로 30도 경사져 협측으로 작용하도록 설정하였다. 전하중의 크기가 변연골 응력 분포에 어떠한 차이가 생기게 하는지를 조사하기 위해 다섯개의 다른 전하중의 크기(0, 200, 400, 600, 800N)를 부여하였다. 모든 분석은 선형 탄성을 가정하여 ABAQUS/CAE(ver6.10-1, HKS, Fremont, CA, USA) 프로그램을 사용하였다. 임플란트 주위 변연골 응력분포의 차이는 전하중의 크기와 관련이 있었다. 100N의 교합력 하에 전하중이 0인 경우 변연골(임플란트 벽에서 0.1mm 떨어진 부분)에서 압축 응력은 28.33MPa이었는데, 전하중을 200N 증가시킬 때마다 1.76MPa씩 증가하였다. 이런 방식으로 800N의 전하중을 가할 때 나타나는 최대 압축 응력은 35.18MPa이었다. 반면 변연골에서의 인장 응력은 전하중이 증가할 수록 감소하였다. 임플란트 고정체와 지대주 간의 전하중은 변연골에서의 압축 응력을 증가시킬 수 있으나 기능력에 비하면 그 효과는 미미할 것으로 판단된다.

• 구강회복응용과학지
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• 제31권1호
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• pp.33-44
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• 2015

목적: 본 연구는 platform matching, platform switching을 시행한 임플란트의 변연골 소실을 비교하여 platform switching 개념의 임상적 의의를 평가하고자 한다. 연구 재료 및 방법: 원광대학교 치과병원 임플란트 센터에서 치료를 진행한 환자를 대상으로 임플란트 식립 시기, 직경, 길이, 지대주 연결방법 및 보철물 연결고정 유무를 조사하였다. 변연골 소실량을 측정하기 위해서 Emago advanced v5.6 프로그램을 사용하여 임플란트 식립 시와 가장 최근 내원 시의 치근단 방사선 사진을 비교하였다. 결과: 환자 82명의 임플란트 150개를 대상으로 6 - 63개월 동안 관찰한 결과 platform matching 임플란트는 $1.16{\pm}0.54mm$, platform switching 임플란트는 $0.68{\pm}0.27mm$의 변연골 소실을 나타내었다. 결론: Platform switching을 시행함으로써 임플란트의 변연골 소실을 줄이는 효과가 있는 것으로 사료된다.