• 한국도로학회논문집
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• 제19권5호
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• pp.33-42
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• 2017

PURPOSES : The purpose of this study is to suggest the construction and quality control method for the re-repair of a deteriorated partial depth repair for sections of Portland cement concrete pavement. METHODS : An experimental construction was conducted to extend the repair width for removing an existing repair section. A removal method was used to ensure early performance for a deteriorated partial depth repair section. Bond strength and split tensile strength were measured at the near vertical interface layer between the existing pavement and repair material. The area was analyzed for various conditions such as the extended repair area and the removing method of the existing repair section. RESULTS : As a result of analysis of bond strength and split tensile strength, the bonding performance of a milling removed section was improved over a cutting and hand breaker removed section. The bond strength was analyzed to increase slightly as the extended repair width for removing the existing repair section increased. The split tensile strength did not show a clear relationship to an increased extended repair width of an existing removed repair section. CONCLUSIONS : The milling removal method should be applied in the removal of existing deteriorated partial depth repair sections. The extended repair width for a re-repair section should be wider than the existing partial depth repair with at least a 75-mm length and width for the bond strength and the split tensile strength.

• The Korean Journal of Ecology
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• 제23권5호
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• pp.377-382
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• 2000

독일가문비 조림지를 식물사회학적 식생조사를 하여 이곳의 원식생인 유럽너도밤나무군락과의 비교를 통해 식생구조, 종조성, 생태계, 생활형의 차이점이 있는지를 조사하였다 독일가문비 조림지에서의 평균출현 종수는 13종이었으며, 이들 종은 생태적 분포특성에 따라 유럽너도밤나무림에 나타나는 종, 자연 침엽수림에 나타나는 종, 그리고 개벌 후의 나지에 나타나는 종 등 크게 세가지 그룹으로 구분되었다. Luzulo-Fagetum군락에서는 Luzula luzuloides가 우점종이나 독일가문비 조림지에서는 Avenella flexuosa가 우점하고 있었다. 조림지 내의 초본식물을 Ellenberg의 지표종에 따라 분석한 결과, 호광성식물과 강산성식물이 증가하고 있었다. 한편 생활형 분석에서는 지표식물, 지상식물 그리고 반지중식물이 증가하고 지중식물은 감소하는 경향을 나타내었다. 위의 결과들은 과거 유럽너도밤나무군락이 우점하던 지역에 조성된 독일가문비 조림지가 생태학적 불안정하다는 것을 보여준다.

• International Journal of Concrete Structures and Materials
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• 제11권2호
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• pp.327-341
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• 2017

Openings in slabs are usually required for many different applications such as aeriation ducts and air conditioning. Opening in concrete slabs due to cutouts significantly decrease the member stiffness. There are different techniques to strengthen slabs with opening cutouts. This study presents experimental and numerical investigations on the use of Carbon Fiber Reinforced Polymers (CFRP) as strengthening material to strengthen and restore the load carrying capacity of R.C. slabs after having cutout in the hogging moment region. The experimental program consisted of testing five (oneway spanning R.C. flat slabs) with overhang. All slabs were prismatic, rectangular in cross-section and nominally 2000 mm long, 1000 mm width, and 100 mm thickness with a clear span (distance between supports) of 1200 mm and the overhang length is 700 mm. All slabs were loaded up to 30 kN (45% of ultimate load for reference slab, before yielding of the longitudinal reinforcement), then the load was kept constant during cutting concrete and steel bars (producing cut out). After that operation, slabs were loaded till failure. An analytical study using finite element analysis (FEA) is performed using the commercial software ANSYS. The FEA has been validated and calibrated using the experimental results. The FE model was found to be in a good agreement with the experimental results. The investigated key parameters were slab aspect ratio for the opening ratios of [1:1, 2:1], CFRP layers and the laminates widths, positions for cutouts and the CFRP configurations around cutouts.

• 대한치과보철학회지
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• 제41권2호
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• pp.111-127
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• 2003

Statement of problem : Resin cements were used widely on all ceramic crowns, but the influence of resin cements on biocells was not understood clearly. Purpose : This study was investigated to evaluate the biocompatibility of resin cements for all-ceramic crowns. Material and Method : The resin cements used in this study were Panavia F (Kuraray Co., Ltd. Japan), Variolink II (Vivadent Ets., Schann / Liechtenstein), and Bistite II (Bistite dual cure resin cement-clear Tokuyama Soda Co. Japan). The viability of normal human oral keratocytes, gingival fibroblast, and gingival fibroblast immortalized by Human Papilloma virus 16 was measured in vitro for evaluation of cytotoxicity on resin cements, and the response of pulp tissue was analyzed and evaluated with light microscope after application of cements at cutting edge of incisors. Results : The normal human oral keratocytes was the most sensitive to toxicity of resin cement, and toxicity of cements was higher in Bistite II than in Variolink II. The cell viability of immortalized gingival fibroblast did not affected by type of cement and cultivation period, but there was a tendency that cytotoxicity in Bistite II was higher than in Variolink II. The cell viability of gingival fibroblast was similar to that of immortalized gingival fibroblast regardless of cement type, but Bistite II showed more toxic than others after 5 days cultivation. The responses of pulp tissue according to cement type were similar after 2 days cultivation, but revealed high toxicity in Bistite II after 10 days cultivation. Conclusion : Variolink II was more biocompatible than any other resin cements used in this study.

• Design & Manufacturing
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• 제11권3호
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• pp.19-24
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• 2017

In these days, increase requirement of TEM (Transmission Electro Microscope) in not only scientific field but also industrial field. Because TEM can measure inner-structure of specimen a variety of materials like metal, bio. etc. When use TEM, specimen should be thin about 50nm. So making for thin specimen, use Ion milling device that include specimen holder. The holder generally made of Aluminium Aluminium holder is worn away easily. For this reason, using time of ion milling with aluminum holder is too short. To solve the problem, we replace aluminium holer to molybdenum alloy holder. In this paper, we design molybdenum alloy holer for CAM and modify CAD modeling for effective machining process. So we array a specimen 3 by 4 and setup orientation for one-shot machining process. Next we make a CAM program for machining. we making a decision two machining strategy that chose condition of tool-path method, step-down, step-over. etc. And then conduct machining using CNC milling machining center. To make clear difference between case.1 and case.2, we fixed machining conditions like feed-rate, main spindle rpm, etc. After machining, we confirm the condition of workpiece and analysis the problems case by case. Finally, case.2 work piece that superior than case.1 cutting with WEDM because that method can not ant mechanical effect on workpiece.

• 융합신호처리학회논문지
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• 제13권2호
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• pp.70-76
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• 2012

본 연구에서는 신장 조직 영상으로부터 자동적으로 사구체 영역을 추출하는 방법을 제안한다. 사구체 조직은 신장의 상태를 나타내는 많은 정보를 포함하고 있기 때문에 사구체 영역의 추출은 신장검사를 자동화하기위한 첫 번째 단계이다. 신장 조직 영상은 신장조직조각을 현미경을 통해서 CCD 카메라로 촬영함으로써 얻어진다. 특히, 사구체 영역과 타 영역과의 차이는 명확치 않아 기존 분할방법에 의해 그 배경으로부터 사구체 영역을 추출하는 일은 쉽지않다. 이에 여러 가지 모양을 갖는 사구체 영역의 경계 에지를 공통의 특징으로서 주목하였다. 우선 가우스 함수에 의한 원영상의 몽롱화 영상을 동적인 임계값으로서 사용하여 이 임계값에 의해 원영상을 2치화 한다. 다음으로 획득한 영상으로부터 일반적인 패턴처리 기법으로 사구체 영역의 경계 에지를 포함하는 모든 에지를 추출한다. 그 다음으로 사구체 영역은 폐곡선에 의해 둘러쌓인 원영상내의 영역을 추출함으로써 얻어진다. 그 결과 사구체 영역이 85%정도 정확하게 추출되어 제안 방법의 유효성을 확인하였다.

• 한국기후변화학회지
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• 제6권4호
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• pp.303-310
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• 2015

This study was conducted to estimate of carbon stock and greenhouse gas (GHGs) removals by tree species and forest type at Gangwon province. We used a point sampling data with permanent sample plots in national forest inventory and national emission factors. GHGs emissions was caclulated using the stock change method related to K-MRV and IPCC guidance. Total carbon stock and greenhouse gas removals were high in deciduous forest and species than in coniferous. The range of annual net greenhouse gas emissions in other deciduous species was from $-11,564.83Gg\;CO_2\;yr^{-1}$ to $-13,500.60Gg\;CO_2\;yr^{-1}$ during 3 years (2011~2013). On the other hand, coniferous forest was temporally converted to source due to reducing of growing stock in 2012. It was that growing stocks and forest area were likely to reduce by the deforestation and clear cutting. This study did not consider other carbon pools (soil and dead organic matter) due to the lack of data. This study needs to complement the activity data and emission factors, and then will find the way to calculate the greenhouse gas emissions and removals in the near future.

• 한국산림과학회지
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• 제100권4호
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• pp.548-557
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• 2011

현재 국제사회에서 가장 비용효과적인 온실가스 감축방안으로 제시되고 있는 REDD를 UNFCCC 체제 내에 도입하기 위한 논의가 두 가지 측면에서 진행되고 있다. 첫째, 산림전용과 산림황폐화의 방지를 통한 탄소배출감축량의 산정방법과 그에 대한 측정방법개발, 둘째, REDD 사업 수혜대상국인 개발도상국에 대한 인센티브 체제 결정이 그것이다. 우리나라의 REDD 사업이 추진된다면 적절한 수준의 상쇄배출권 확보를 통해 포스트 교토체제에서 한국에게 온실가스 감축을 위한 폭넓은 기회를 제공해 줄 수 있을 것이다. 그를 위해 REDD를 국내에 도입하기 위해서는 무엇보다 법제도적 확실성 보장과 더불어 적절한 투자대상국들과의 거버넌스 구축이 필요하다.

• 한국정보통신학회논문지
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• 제27권1호
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• pp.8-14
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• 2023

기존의 자기지도 학습 기반의 CutPaste 기법은 정상 이미지에서 특정 패치를 자르고 붙이는 방법으로 합성 데이터를 생성한 뒤 이상탐지를 수행하였다. 그러나 이런 방식으로 생성된 합성데이터는 패치의 경계에 뚜렷한 차이가 나타나는 문제가 발생된다. 이러한 문제를 해결하기 위한 NSA 기법은 Poisson Blending을 통해 자연스러운 합성 데이터를 생성하여 더 높은 이상탐지 성능을 달성하였다. 그러나 NSA 기법은 클래스마다 조정해야하는 하이퍼 파라미터가 많은 단점을 가지고 있다. 본 논문에서는 합성 패치의 크기를 매우 작게 하는 단순한 방법으로 정상과 유사한 합성 데이터를 생성하였다. 이 때 패치가 매우 지역적으로 합성되기 때문에, 지역적인 특징을 학습하는 모델을 사용하면 합성 데이터에 쉽게 과적합 될 수 있다. 따라서 전역적인 특징을 학습하는 gMLP를 사용하여 이상탐지를 수행하였고, 단순한 합성 방법으로도 기존 자기 지도 학습 기법보다 더 높은 성능을 달성할 수 있었다.

• Tribology and Lubricants
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• 제39권5호
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• pp.190-196
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• 2023

Anti-adhesion coatings are very important in the processing of adhesive materials such as optical clear adhesive (OCA) films. Choosing the appropriate release coating material for dies and tools can be quite challenging. Hydrophobic surface treatment is usually performed, and its performance is often estimated by the static water contact angle (CA). However, the relationship between the release performance and the CA is not well understood. In this study, the water CAs of surfaces coated with anti-adhesion materials and the peel strengths of the acrylic-based adhesive films are evaluated. STC5 and SUS304 are selected as the base materials. Base materials with different surface roughnesses are produced by hairline finishing, mirror-polishing, and end milling. Four fluoropolymer compounds, including a self-assembled monolayer, are selected to make the base surface hydrophobic. Static, advancing, and receding CAs are mostly increased due to the coating, but the CA hysteresis is found to increase or decrease depending on the coating material. The peel strengths all decreased after coating and are largely dependent on the coating material, with significantly lower values observed for fluorosilane and perfluoropolyether silane coatings. The peel strength is observed to correlate better with the static CA and advancing CA than with the receding CA or hysteresis. However, it is not possible to accurately predict the anti-adhesion performance based on water CA alone, as the peel strengths are not fully proportional to the CAs.