• 한국전기전자재료학회논문지
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• 제35권1호
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• pp.66-71
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• 2022

The insulator used for the transmission line is a device that is bonded with a cap, pin, ceramic, and cement to withstand insulation capacity and mechanical load. The insulator design can help to reduce the dispersion of the electric field; thus, the optimization of today's design, especially as demanded power grows, is critical. The designs of four manufacturers were used to perform a comparative analysis. Under dry circumstances of the new product, an electric field distribution study was done with no pollutants attached. Manufacturer D's design has the best voltage uniformity of 24.33% and the arc length of 500 mm or more. Manufacturer C's design has an equalizing voltage of more than 2% higher than that of other manufacturers. The importance of the design of the insulator and the number of connections according to the installation conditions is very efficient for transmission lines that will increase in the future.

• Advances in materials Research
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• 제11권4호
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• pp.251-277
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• 2022

Disposal of industrial waste in cities where municipal authorities permitting higher floor area ratio coupled with increasing living standards, a lot of demolition waste is being generated. Its disposal is a challenge particularly in megacities where no landfills are available. The ever-increasing cost of building construction materials also necessitates consuming demolition wastes in a useful manner to save fresh natural raw materials. In the present work, the crushed waste glass is used in high-strength concrete as a partial replacement of fine aggregate. The control concrete of grade M60 was proportioned following BIS 10262-2009. The crushed waste glass has been used as a partial replacement with varying percentages of 10, 20, 30, and 40% by weight of fine aggregate. Experimental tests were carried on the fresh and hardened state of the concrete. The effect of crushed waste glass on the workability of the concrete has been investigated. Non-destructive tests, acid attack tests, compressive strength, split tensile strength, and X-ray diffraction analysis was carried out for the control concrete and concrete containing crushed waste glass after 7, 28, and 270 days of normal curing. The results show that for the same w/c ratio, the workability of concrete increases with increasing replaced crushed waste glass content. However, the decrease in compressive strength of the concrete after 28 days of normal curing and further after 28 days of acid attacks, up to 30% replacement level of fine aggregate by the crushed waste glass is insignificant.

• 융합경영연구
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• 제3권4호
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• pp.13-20
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• 2015

This study examined the relationship between working capital management and performance of listed companies Stock Exchange in Tehran. A total of 40 companies from the cement industry for the period 2007 to 2010 of which only 25 were selected for this study had the condition. In order to achieve the objectives, this study surveys the exploration of correlation regression analysis and used the curve obtained, the regression equation. To test the hypothesis, quantitative analysis was used as a method. The results showed a negative relationship between the variables of working capital management and the company's performance and the only variable cash conversion cycle did not show a significant relationship. There is often a negative correlation between the variables studied. This study is based on five assumptions impact of working capital management on corporate profitability is examined. Therefore, the results suggest that the variables in working capital (average collection of receivables, average inventory turnover period, the average net debt and average transaction cycle) and net operating profit is significant negative correlation Net cash conversion cycle and only illustrates the relationship is not significant. Thus, it showed that in debt collection and debt payment period, the turnover of inventory and net trade cycle to reduce the profitability of companies will increase.

• The Journal of Advanced Prosthodontics
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• 제16권1호
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• pp.48-56
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• 2024

PURPOSE. To evaluate the metameric disparities among monolithic zirconia materials with differing yttrium compositions across various lighting conditions. MATERIALS AND METHODS. Thirty-six square-shaped zirconia samples measuring 10 × 10 × 0.5 mm were prepared from monolithic zirconia materials with three different yttrium contents. A 0.2 mm thick layer of polymerized dual-polymerizable self-adhesive resin cement was created using a silicone mold with the same dimensions as the prepared zirconia specimens. To evaluate metamerism, color measurements were conducted using a spectrophotometer device on a neutral gray background in a color measurement cabinet that offers four different illumination environments. All samples underwent aging by subjecting them to 10000 thermal cycles using a thermal cycle tester. Following thermal aging, color measurements were taken once more, and the data were recorded using the CIE L^*, a^*, b^* color system. Two-way ANOVA and Post-hoc Bonferroni tests were employed to analyze the data. RESULTS. It was observed that there was no statistical difference among the color measurements made in different illumination environments of the monolithic zirconia ceramics used to evaluate metamerism (P > .05). This observation remained consistent both before and after thermal aging. After thermal aging, the color of monolithic zirconia materials exhibited a tendency towards red and yellow hues, accompanied by a decrease in brightness levels. CONCLUSION. It can be stated that different illumination conditions did not affect the metamerism of monolithic zirconia materials, but there was a color change in monolithic zirconia materials after a thermal aging period equivalent to one year.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권3호
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• pp.215-219
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• 2012

Cemento-ossifying fibroma (COF) is a benign fibro-osseous tumor with fibrous tissue, abnormal cement and bone, or a combination of such elements. These are slow-growing lesions and are more frequent in women. Here, we report the case of a 28-year-old Korean woman. The patient having no underlying disease complained about facial swelling and asymmetry. A firm mass with impacted molars and teeth deviation on the right maxilla was observed. A computed tomography scan was taken and an incisional biopsy was performed. Following this, COF was diagnosed. Complete surgical removal of the lesion was carried out. A post-operative follow-up was conducted and 3 months later the patient reported no discomfort or any sign of recurrence in regards to the lesion. Differential diagnosis with fibrous dysplasia and the COF is important because of the treatment choice. We report a case of COF and offer a review of the literature on this article.

• Journal of Korean Neurosurgical Society
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• 제42권2호
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• pp.112-117
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• 2007

Objective : Kyphoplasty and vertebroplasty are two minimally invasive procedures for osteoporotic vertebral compression fractures. The purpose of this retrospective study was to compare the radiological findings and clinical outcomes between two procedures. Methods : Osteoporotic vertebral fractures were treated in 76 vertebrae, using kyphoplasty (n=35 vertebrae) and using vertebroplasty (n=41 vertebrae). Fractured vertebral bodies were diagnosed by correlating the clinical symptoms with radiologic study. The responses of pain symptoms were measured by a self-reported Visual Analog Scale (VAS) score. Plain X-rays were checked preoperatively and postoperatively at admission and 6 months. The vertebral body height and kyphotic angle were measured to assess the reduction of the sagittal alignment. Results : The mean pain scores were decreased significantly for both procedures postoperatively, but there were no significant differences between two groups. Kyphoplasty led to a significant reduction of the vertebral body height and improvement of kyphotic angle. There were no neurological deficits after kyphoplasty, but one patient experienced paraparesis after vertebroplasty. During the 6 months follow-up both procedures provided stabilization of the sagittal alignment. Conclusion : Kyphoplasty and vertebroplasty are considered effective minimally invasive techniques for the stabilization of osteoporotic vertebral body fractures, leading to a statistically significant reduction in pain. Kyphoplasty significantly restore sagittal alignment. Also, complications and the incidence of bone cement leakage are significantly lesser than vertebroplasty. Therefore, kyphoplasty seems to be reasonable procedure for osteoporotic vertebral body compression fractures when medical treatment fail.

• Journal of Chest Surgery
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• 제29권3호
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• pp.346-349
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• 1996

This 32 year old female patient underwent left radical mastectomy due to ductal carcinoma on May 1990, and treated with FAM (5-fluorouracil, Adriamycin and Mitomycin C) regimen postoperatively. However, right cervical Iymph node enlargement and facial edema progressively developed since December 199). On April 1994, operation was performed, and findings were as followes; x4$\times$5$\times$7 to 1 : 1 $\times$ 1 cm sized multiple enlarged and hyperemic Iymph nodes were scatterred throughout submandibular area to the junction of superior vents cave and pericardium, and partially invaded both anterior segmental lobe, sternum and both distal tip of clavicles. After radical dissection of the nodes of neck and mediastinal nodes, and wedge resection of both anterior segments of lung, and partial resection of both clavicle tips and total sternum. The both innominate veins and superior vena cava were partially obstructed by invaded cancer SVC reconstruction was done with preclotted 10$\times$ 10$\times$ 18mm Y shap d woven Dacron graft, which was anastomosed to the point of the junction of subclavian vein and jugular vein after cross clamping both veins and 2cm above the pericardial junction with one arm clamp. After maintaining blood drainage to the SVC from the right side, left innominate vein was anastomosed with 4-0 Prolene continuous running suture. Bone cement was used for resected sternal portion and clavicular ends were fixed to postal portion with 18 Gauge wires. The patient was treated with radiation and chemotherapy after discharge, and there were no evidence of regrowing of the mass nor obstruction of the graft inspite of no antithrombotic therapy.

• 품질경영학회지
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• 제45권4호
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• pp.995-1002
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• 2017

Purpose: The purpose of this study was to evaluate the color stability of composite resins used for splinting teeth by comparing a self-cure resin cement (Superbond C&B, SB), a flowable composite resin (G-aenial Universal Flo A2, GU), and a composite resin exclusively used for splinting teeth (G-Fix, GF) before and after aging in NaOCl. Methods: Resin samples were fabricated to a size of 2 mm thickness and 8.5 mm diameter and light-cured with an LED light curing unit (G-Light, n = 12). Immediately after fabrication, CIE L*a*b* values of the resin samples were measured with a spectrophotometer (CM-5) as baseline. Then, the resin samples were immersed in 5% NaOCl at $60^{\circ}C$ and the color was measured after 23 hours every day for 4 days. Data were analyzed with one-way ANOVA followed by Duncan post hoc test (p<0.05), and color differences (${\Delta}E$) of resin samples before and after NaOCl aging were also calculated. Results: For SB, there were no changes in L* and a* values but changes were observed in b* values. For GU, there were no changes in L* and b* values but in a* values. For GF, changes were observed in L*, a*, and b* values. All resin samples showed highest ${\Delta}E$ between baseline and the 1st day of NaOCl immersion. ${\Delta}E$ of SB, GU, and GF was 4.6 - 5.8, 4.9 - 7.9, and 9.9 - 16.9, respectively. GF showed highest color change during NaOCl aging. Conclusion: The results of this color quality evaluation showed that the composite resin exclusively used for splinting teeth might be more vulnerable to color change during intraoral service.

• 지질공학
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• 제20권1호
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• pp.1-12
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• 2010

본 연구에서는 인천 해안 LPG공동의 수리화학적 안정성을 평가하기 위해 공동 유출수 및 주변 지하수에 대한 수리지구화학적 및 미생물학적 특성을 평가하였다. 수질특성을 파악하기 위하여 2007년 2월, 5월, 8월, 10월에 걸쳐 시료채취 및 수질분석을 실시하였다. 프로판공동 지하수의 경우 pH는 8.1~12.4의 높은 값을 보였으며 이는 공동건설 및 관측정설치에 사용된 시멘트 그라우팅 물질의 용해영향으로 사료된다. 전기전도도는 시료채취 시기별로 큰 차이를 보였으며, 음의 산화환원전위는 유출수 및 지하수가 환원환경에 있음을 지시하였다. 수질분석결과 유출수 및 지하수의 수질유형은 모두 Na-Cl type으로 나타났으며 이는 해수의 영향으로 판단된다. 호기성세균, 혐기성세균, 점액질세균, 황산환원세균 모두 500 CFU/mL 미만으로 낮은 값을 보였으며 급격한 미생물 성장은 관찰되지 않았다. 현재로선 공동 운영에 지장을 주는 특이적 수리화학적 현상이 발견되지는 않았으나 지속적인 모니터링이 필요하다.

• The Journal of Advanced Prosthodontics
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• 제6권1호
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• pp.8-13
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• 2014

PURPOSE. The purpose of this study was to evaluate whether surface treatments affect the translucency of laminate veneers with different shades and thicknesses. MATERIALS AND METHODS. A total of 224 disc-shaped ceramic veneers were prepared from A1, A3, HT (High Translucent) and HO (High Opaque) shades of IPS e.max Press (Ivoclar Vivadent) with 0.5 mm and 1.0 mm thicknesses. The ceramics were divided into four groups for surface treatments. Group C: no surface treatments; Group HF: etched with hydrofluoric acid; Group SB: sandblasted with 50-${\mu}m$ $Al_2O_3$; and Group L; irradiated with an Er;YAG laser. A translucent shade of resin cement (Rely X Veneer, 3M ESPE) was chosen for cementation. The color values of the veneers were measured with a colorimeter and translucency parameter (TP) values were calculated. A three-way ANOVA with interactions for TP values was performed and Bonferroni tests were used when appropriate (${\alpha}=0.05$). RESULTS. There were significant interactions between the surface treatments, ceramic shades and thicknesses (P=.001). For the 0.5-mm-thick specimens there were significant differences after the SB and L treatments. There was no significant difference between the HF and C treatments for any shades or thicknesses (P>.05). For the 1-mm-thick ceramics, there was only a significant difference between the L and C treatments for the HT shade ceramics (P=.01). There were also significant differences between the SB and C treatments except not for the HO shades (P=.768). CONCLUSION. The SB and L treatments caused laminate veneers to become more opaque; however, HF treatment did not affect the TP values. When the laminate veneers were thinner, both the shade of the ceramic and the SB and laser treatments had a greater effect on the TP values.