• 대한예방의학회:학술대회논문집
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• 대한예방의학회 1998년도 제50차 추계 학술대회 연제집
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• pp.217-218
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• 1998

• 대한치과보철학회지
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• 제40권5호
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• pp.525-535
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• 2002

The purposes of this study were to evaluate the adherence of bacteria on various denture base resin materials and effects of chitosan, added to denture base materials on bacterial adherence. PMMA denture base resin such as heat-cured Vertex-RS, self-cured Vertex-SC and 4-META denture base resin such as heat-cured Meta-Dent, self-cured Meta-Fast were used in this study Samples were divided into two groups the denture base resin with chitosan, without chitosan Streptococcus mutans and Lactobacillus casei were used in this study. The surface of samples was observed by SEM. When chitosan was added to M17 and MRS broth, viable cell count of bacteria was reduced. Viable cell count of Streptococcus mutans on the samples decreased as follows : Meta-Dent, Vertex-SC, Meta-Fast, Vertex-RS. Viable cell count of Lactobacillus casei on the samples decreased as follows: Vertex-RS, Meta-Dent, Meta-Fast, Vertex-SC. The resin with chitosan showed lower adherence of bacteria than without chitosan. The images of SEM showed that the surface of the resin with chitosan was rougher than that of without chitosan. These results showed that the denture base resin materials with chitosan have rougher surface than without chitosan, but less bacteria adhered on them.

• 한국작물학회지
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• 제49권5호
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• pp.381-388
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• 2004

In Korea, production of super sweet corn has been economically feasible and is substituting for traditional sweet corn due to better flavor in recent years. Major limiting factors for super sweet corn production are low field emergence and low seedling vigor. The optimum water potential (WP) for the priming of normal and aged seeds of dent, sweet (su) and super sweet (sh2) corns was studied to improve low seed quality. Seeds were primed at 0, -0.3, -0.6, -0.9, and -1.2 MPa of polyethylene glycol (PEG) 8000 solution at $15^{\circ}C$ for 2 days. Priming effects differed depending on the type of corn, seed quality, and WP of PEG solution. Although WP of priming solution did not influence the emergence rate of extremely high quality normal dent corn seeds, it reduced time to $50\%$ emergence (T50) and increased plumule weight. In contrast, the emergence rate of aged field corn was improved by seed priming at 0 MPa and plumule weight and $\alpha-amylase$ activity was enhanced. The optimum WP for both normal and aged sweet and super sweet corn seeds was between -0.3 and -0.6 Mpa. At the optimum WP emergence rate, $\alpha-amylase$ activity, and content of DNA and soluble protein increased, while T50 and leakage of total sugars and electrolytes reduced.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.223-226
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• 2003

We propose an improvement method for a $\underline{G}ate$ $\underline{OX}ide(GOX)$ thinning at the edge of $\underline{S}hallow$ $\underline{T}rench$ $\underline{I}solation(STI)$, when STI is adopted to Dual Gate Oxide(DGOX) Process. In the case of SOC(System On-a-Chip), the DGOX process is usually used for realizing both a low and a high voltage parts in one chip. However, it is found that the severe GOX thinning occurs from at STI top edge region and a dent profile exists at the top edge of STI, when conventional DGOX and STI process carried out in high density device chip. In order to overcome this problem, a new DGOX process is tried in this study. And we are able to prevent the GOX thinning by H2 anneal, partially SiN liner skip, and a method which is merged a thick sidewall oxide(S/O) with a SiN pull-back process. Therefore, a good subthreshold characteristics without a double hump is obtained by the prevention of a GOX thinning and a deep dent profile.

• 열처리공학회지
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• 제20권2호
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• pp.72-77
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• 2007

Abrasive wear between piston ring face and cylinder liner is an extremely unpredictable and hard-to-reproduce phenomenon that significantly decreases engine performance. Wear by abrasion are forms of wear caused by contact between a particle and solid material. Abrasive wear is the loss of material by the passage of hard particles over a surface. From the pin-on-disk test, particle dent test and scuffing test, abrasive wear characteristics of diesel engine cylinder liner-piston ring have been investigated. Pin-on-disk test results indicate that abrasive wear resistance is not simply related to the hardness of materials, but is influenced also by the microstructure, temperature, lubricity and micro- fracture properties. In particle dent test, dent resistance stress decreases with increasing temperature. From the scuffing test by using pin-on-disk tester, scuffing mechanisms for the soft coating and hard coating were proposed and experimentally confirmed.

• 한국항공우주학회지
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• 제48권8호
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• pp.581-588
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• 2020

고전압 기폭관의 노화 특성에 관하여 연구하였다. 노화 특성 관측을 위해 먼저 고전압 기폭관의 주요 구성품을 분류하고, 고장 메커니즘을 정의하였다. 위력과 감도 측면에서 노화 특성을 정의하였으며, HFC (Heat Flow Calorimetry)를 통해 계산된 활성화 에너지와 아레니우스 이론을 기반으로 가속노화시험 계획을 수립하였다. 노화된 시료를 이용하여 민감도 시험인 Neyer Test와 위력시험인 Dent Test를 통하여 성능 변화를 관측하였다. 민감도 시험을 통해 구한 반폭점에서 노화 경향을 관찰하였으나 관련 규격을 고려하면 충분히 긴 수명을 가지고 있는 것으로 분석되었다.

• Restorative Dentistry and Endodontics
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• 제25권4호
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• pp.499-508
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• 2000

본 연구에서는 이종의 디지털 방사선사진술이 수복물의 방사선불투과성 비교에 적절하게 이용될 수 있는지의 여부를 평가하고, 이 기법을 이용하여 수종의 compomer 및 유동성 레진의 방사선불투과도를 측정, 비교하고자 하였다. Aluminum step wedge를 방사선사진촬영 하여 기 존의 transmission densitometer와 CD-Dent (phosphor scanning system) 및 RVG$^{(R)}$ (CCD system) 등 두 종류의 디지털 방사선사진술과의 광학밀도 상관관계를 평가하였고, 두께 2mm, 지름 5mm인 원형의 금속주형을 이용하여 Dyract$^{(R)}$ AP, Compoglass$^{(R)}$ 및 Dyract flow$^{(R)}$ 등 3종의 compomer와 Ultraseal-XT$^{(R)}$ plus$^{TM}$, Revolution$^{TM}$, Aeliteflo$^{TM}$ 및 Tetric-flow$^{(R)}$ 등 4종의 유동성 레진의 시편을 각각 5개씩 제작후 방사선불투과성을 측정하고 비교, 평가하여 다음과 같은 결과를 얻었다. 1. Aluminum step wedge를 사용한 광학밀도 측정곡선을 비교한 바, 통상적인 방사선사진술로 얻은 필름의 상에서 transmission densitometer로 방사선불투과도를 측정 한 곡선과 CD-Dent 및 RVG$^{(R)}$ 등 디지털 방사선사진술로 얻은 상에서 CADIA로 불투과도를 측정한 곡선들 사이에서 각각 매우 높은 역상관관계가 나타났다(${\gamma}$=-0.95, ${\gamma}$=-0.98 ; p<0.05). 2. 모든 수복채 공히 상아질과 유사하거나 높은 방사선불투과도를 나타내었고 (p<0.05), compomer인 Dyract$^{(R)}$ AP와 Compoglass$^{(R)}$, 그리고 유동성 레진인 Tetric-flow$^{(R)}$는 통상적인 방사선사진술 및 2종의 디지털 방사선사진술에서 공히 유동성 레진인 Revolution$^{TM}$과 Aeliteflo$^{TM}$, 그리고 상아질에 비해 유의하게 높은 방사선불투과도를 나타내었다 (p<0.05). 3. Compomer인 Dyract$^{(R)}$ AP와 Compoglass$^{(R)}$, 그리고 유동성 레진인 Tetric-flow$^{(R)}$는 통상적인 방사선사진술 및 CD-Dent 디지털 방사선사진술에서 공히 법랑질에 비해 높은 방사선불투과도를 나타내었고(p<0.05), compomer인 Dyract flow$^{(R)}$는 통상적인 방사선사진술에서만 법랑질에 비해 높은 방사선불투과도를 나타내었다(p<0.05).

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2002년도 춘계공동학술발표회요약집
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• pp.41.2-41
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• 2002

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 춘계학술발표회
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• pp.962-962
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• 2005

• Steel and Composite Structures
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• 제19권1호
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• pp.223-236
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• 2015

Despite the proliferation of the industrial application of steel tubes, the effect of collision on the surface of steel tubes subject to cyclic loading has largely remained untouched. This paper studies the fatigue behavior of steel tubes which are impacted by an external object. A dent imperfection caused by a collision was modeled and fatigue tests were conducted using a MTS machine. Fatigue life as well as the failure modes were thoroughly discussed in a way that the fatigue life of the dented tubes with similar geometrical specifications at full-scale can be generalized.