• 대한치과의사협회지
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• 제50권7호
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• pp.384-393
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• 2012

Successful treatment of a badly broken down tooth with pulpal disease depends not only on good endodontic therapy, but also on good prosthetic reconstruction of the tooth after endodontic therapy is completed. The ideal treatment of endodontically treated teeth has been widely and controversially discussed. Endocrown is a restorative option for endodontically treated teeth. Endocrown design incorporates the core and short post into the crown as a single restoration. The preparation of endocrown consists of a circular equigingival butt-joint margin and central retention cavity of the entire pulp chamber instead of employing intraradicular posts. This design significantly increases the surface area of the preparation available for cementation. It is particularly useful in young patient teeth for long-term provisional restoration and in teeth with short clinical crowns. This technique represents a promising and conservative method for the treatment of endodontically treated teeth that require long-term protection and stability. Endocrown can be considered as a feasible alternative to full crowns or composite overlays for the restoration of non vital teeth.

• 통합자연과학논문집
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• 제6권3호
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• pp.151-157
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• 2013

The ion exchange resins were synthesized from 1-aza-18-crown-6 macrocyclic ligand attached to styrene (2th petroleum in 4th class hazardous material) divinylbenzene (DVB) copolymer with crosslinks of 1%, 6%, and 15% by substitution reaction. These synthetic resins were confirmed by chlorine content, elementary analysis, surface area, and IR-spectrum. The object of this study was to seperate the metal ion absorbed in reinforcement water fire extinguishing agent. As the results of the effects of pH, equilibrium arrival time, and crosslink of synthetic resin on metal ion adsorption for resin adsorbent, the metal ions were showed high adsorption at pH 3 or over and adsorption equilibrium of metal ions was about 2 hours. In addition, adsorption selectivity for the resin in water was the order of Al (III) > Ni (II) > Sm (III) ions, adsorbability of the metal ions was in the crosslinks order of 1%, 6%, and 15%.

• 통합자연과학논문집
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• 제10권4호
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• pp.225-231
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• 2017

Cryptand resins were synthesized by mixing 1-aza-18-crown-6 macrocyclic ligand with styrene divinylbenzene copolymer having 1%, 2%, 5%, and 10% crosslink by a substitution reaction. These synthetic resins were confirmed by chlorine content, elementary analysis, SEM, surface area, and IR-spectrum. As the results of the effects of pH, crosslink of synthetic resin, and dielectric constant of a solvent on uranium ion adsorption for resin adsorbent, the uranium ion showed high adsorption at pH 3 or over. Adsorption selectivity for the resin in methanol solvent was the order of uranium ($UO_2{^{2+}}$) > calcium ($Ca^{2+}$) > neodymium ($Nd^{3+}$) ion, adsorbability of the uranium ion was the crosslink in order of 1%, 2%, 5%, and 10% and it was increased with the lower dielectric constant.

• The International Journal of Costume Culture
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• 제6권2호
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• pp.69-82
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• 2003

The Scythians had a veritable passion for adornment, delighting in decorating themselves no less than their horses and belongings. Their love of jewellery was expressed at every turn. The most magnificent pieces naturally come from the royal tombs. In the area of the neck and chest the Scythian had a massive gold Torques, a symbol of power, made of gold, turquoise, cornelian coral and even amber. The entire surface of the torque, like that of many of the other artefacts, is decorated with depictions of animals. Scythian Torques are worn with the decorative terminals to the front. It was put a Torque on, grasped both terminals and placed the opening at the back of the neck. It is possible the Torque signified its wearer's religious leadership responsibilities. Scythian Torques were divided into several types according to the shape, Torque with Terminal style, Spiral style, Layers style, Crown style, Crescent-shaped pectoral style.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.845-862
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• 2009

Recently, Tunnel in soil has been designed frequently because Mountain Tunnel has been increased rapidly due to straight of horizontal curve and residents' complaints, tunnel portal has been planned at closed to surface for minimization of environmental damage. To excavate tunnel in soil, where displacement and crushing occur in tunnel face and crown because of unstable ground condition, appropriate reinforcement method needed. On this paper, through design and construction of the soil tunnel, consider application of reinforcement method, economical efficiency and stability.

• 대한공간정보학회지
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• 제24권4호
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• pp.67-74
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• 2016

공간해상도가 높은 드론 영상은 수목 밀도가 높은 지역에서 추출 한계를 갖는 기존 연구의 대안으로 떠오르고 있다. 본 연구에서는 드론 영상으로부터 수목이 우거진 산림 지역 내 수목 개체를 추출하였다. 영상 분할 과정을 거쳐서 추출되는 수목 개체 인식을 위해, DSM(digital surface model), 그리고 R, G, B 밴드 모두를 조합한 경우와 각각을 분리 조합한 경우의 영상 분할 결과를 비교하였다. 또한, 낙엽수림의 수목 우거짐의 변화를 시기별 영상별로 실험하였다. 3, 4, 5월 영상 중 숲이 울창한 5월의 경우 현지 측량한 나무를 기준으로 한 수목 개체 추출율은 50%로 나타났고, 수관폭 정확도 분석 결과 RMSE(root mean square error)가 1.5미터 이하로 가장 좋은 결과를 보였다. 실험지역의 추출은 중간 나무, 작은 나무 2가지 크기로 추출하였으며 작은 크기의 나무가 추출 정확도가 더 높았다. 이를 바탕으로 수고 추출을 하고, 수관폭과 흉고직경간의 관계식을 이용하여 흉고직경을 추정한다면, 임목재적 추정 및 산림바이오매스 추정까지 가능할 것으로 보인다.

• The Korean Journal of Ecology
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• 제8권2호
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• pp.109-117
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• 1985

This report is a part of the investigations of the secondary vegetation successions carried out and the analysis of soil properties in the burned areas of forest. The fires-crown fire and surface fire-were occurred at April, 1978 and February, 1984. The investigations were carrited out from August 10. 1983 to September 25, 1984. The burned areas studied are located in southern slope of Mt. Ssalibagu (above sea-level, 590m), So-myon, Sungju-gun, Chollanam-do, Korea. The results are as follows: The floristic compositions of the burned area at the 5th year after the fires were 85 families, 250 genera, 321 species and 53 varieties. Among them, 85 families, 127 genera, 129 species and 30 varieties were found in the currently burned area. In all the sampling sites (10*10cm), 31 and 57 species were found in the currently burned and in the 5th years after the fires, respectively. Miscanthus sinensis var. purpurascens, Quercus serrata and Festuca ovina were dominant species in the both areas. Biological spectra in both the burned areas showed $H-D_1-R_5-e$ type. Degree of the succession(DS) was 412-884 in the 5th years passed burned area and it was high level. Species diversity index(H) was 0.59~1.13 and evennes index(e) was 0.43~0.79, these indexes between both areas were different considerably. Indexes of similarity between both areas were different, too, but that between $B_1$ and $B_6$ was the highest (CCj=0.5). Probably this phenomenon is due to the great numbers of the pine trees appeared simulataneously. Content of the organic matter, N, P, K and Ca of soil in the burned area at the 5th years after the fires was lower than that of soil in the currently burned area.

• 터널과지하공간
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• 제15권1호
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• pp.71-79
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• 2005

지표로부터 터널까지의 토피가 얇고 지반이 풍화토 혹은 풍화암으로 연약한 곳에서 두 터널이 교차되도록 굴찰할 때 교차부의 역학적 안정성을 계측으로 확인하였다. 터널의 시공방법은 주로 12 m의 강관 다단그라우팅 3열로 막장전방을 선보강한 후 터널상반부를 굴착하였고 두 터널의 교차부는 자천공 록볼트로 추가 보강하였다. 터널 굴착 후 교차부 주변 지반의 변위가 수렴되어 역학적인 안정을 확인 할 수 있었다. 최종적으로 수렴된 변위는 천단침하와 내공변위가 각각 약 6-7 mm. 약 5 mm로 터널의 심도와 연약한 지반조건을 고려할 때 작은 값이었다. 따라서 길이 12 m의 강관 다단그라우팅 3열로 막장전방을 보강한 후 터널 교차부 주변을 굴착한 것은 변위를 억제하고 터널의 안정화에 효과적인 것으로 분석되었다.

• 터널과지하공간
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• 제33권3호
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• pp.126-140
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• 2023

본 연구에서는 석회석 광산에서 발생한 지반침하지에 대해 라이다 기반 정밀 형상 모델을 활용하여 침하 원인을 분석하였다. 드론 및 지상 기반 라이다 시스템을 활용하여 침하지 지표 및 갱도에 대한 정밀 형상 모델 구축을 수행하고 현장 지질조사 및 암반 분류 결과를 활용하였다, 정밀 형상 모델을 통해 침하지 주변부 크라운필러 두께 및 단층 분포, 침하지 및 침하 적치물 부피 계산, 침하 지표 경사 분석을 수행하였다. 이와 같은 분석을 통해 석회석 광산에서 발생한 지반침하 원인을 규명하였다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제43권2호
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• pp.70-76
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• 2017

The purpose of this study was to perform a literature review of short implants in the posterior maxilla and to assess the influence of different factors on implant success rate. A comprehensive search was conducted to retrieve articles published from 2004 to 2015 using short dental implants with lengths less than 10 mm in the posterior maxilla with at least one year of follow-up. Twenty-four of 253 papers were selected, reviewed, and produced the following results. (1) The initial survival rate of short implants in the posterior maxilla was not related to implant width, surface, or design; however, the cumulative success rate of rough-surface short implants was higher than that of machined-surface implants especially in performance of edentulous dental implants of length <7 mm. (2) While bone augmentation can be used for rehabilitation of the atrophic posterior maxilla, short dental implants may be an alternative approach with fewer biological complications. (3) The increased crown-to-implant (C/I) ratio and occlusal table (OT) values in short dental implants with favorable occlusal loading do not seem to cause peri-implant bone loss. Higher C/I ratio does not produce any negative influence on implant success. (4) Some approaches that decrease the stress in posterior short implants use an implant designed to increase bone-implant contact surface area, providing the patient with a mutually protected or canine guidance occlusion and splinting implants together with no cantilever load. The survival rate of short implants in the posterior edentulous maxilla is high, and applying short implants under strict clinical protocols seems to be a safe and predictable technique.