• 비파괴검사학회지
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• 제29권6호
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• pp.534-549
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• 2009

As the thin film technology has emerged in various fields, adhesion of the film interface becomes an important issue in terms of the longevity and durability of thin film devices. Diverse nondestructive methods utilizing acoustic techniques have been developed to assess the interfacial integrity. As an effective technique based on the ultrasonic wave focusing and the surface acoustic wave(SAW) generation, scanning acoustic microscopy(SAM) has been investigated for adhesion evaluation. Visualization of film microstructures and quantification of adhesion weakness levels by SAW dispersion are the recent achievements of SAM. To overcome the limitations in the theoretical dispersion model only suitable for perfectly elastic and isotropic materials, a new model has been more recently developed in consideration of film anisotropy and viscoelasticity and applied to the adhesion evaluation of polymeric films fabricated on semiconductive wafers.

• 한국전산구조공학회논문집
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• 제23권4호
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• pp.403-407
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• 2010

게코 접착 시스템은 보(beam)의 형상을 가지는 seta와 접착패드 역할을 하는 spatula로 구성된다. 본 논문에서는 보 접착 모델(ahhesive beam contact model)을 사용하여 게코(gecko) 접착 시스템의 접착 메커니즘의 해석을 수행한다. 보 접착 모델은 접촉면에서 불균일한 응력 분포를 가지는 특징이 있으며, 접촉면에서의 최대 인장 응력(tensile stress)에 의하여 접착/분리 메커니즘이 결정된다. 접착패드 역할을 하는 spatula는 최대 인장응력을 감소시키는 역할을 하며, 이로 인해 접착력이 증가한다. 역방향 하중에 대해서는 spatula에 의하여 최대 압축 응력(compressive stress)이 감소하며, 이러한 현상에 의하여 접착력과 분리력의 비대칭성이 발생한다. 본 연구에서는 보 접착 모델의 해석을 위해 유한요소법(Finite Element Method)을 사용되며, spatula effect를 위한 해석 결과가 제시된다.

• 한국컴퓨터그래픽스학회논문지
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• 제25권1호
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• pp.1-11
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• 2019

책상 위에 놓인 젖은 옷감을 움직이기 위해서는 마른 옷감을 움직일 때와 비교하여 더 많은 힘이 필요하게 되는데, 그 이유는 젖은 옷감과 책상의 표면 사이의 위치한 유체가 접착력을 만들어내기 때문이다. 본 논문은 젖은 옷감이 물체의 표면에 달라 붙는 현상에 집중하여 젖은 옷감을 표현한다. 접착력을 계산하기 위해서 우리는 섬유 관련 연구 분야에서 실제 실험을 기반으로 모델링한 접착력 모델을 활용하였고, 기존 연구와 다르게 젖은 옷감이 물체와 닿아있는 부분에서도 자연스럽게 주름이 만들어지는 모습을 표현한다. 젖은 옷감이 물체에 달라 붙는 현상과 더불어 젖은 옷감끼리도 서로에게 달라 붙는 현상을 표현함으로써 보다 실제의 젖은 옷감과 유사한 결과를 보인다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.2-5
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• 2011

This paper presents a numerical study on multiphase flows induced by wall adhesion The CSF(Continuum Surface Force} model is used for the calculation of the surface tension force and implemented in an in-house solution code(PowerCFD). The present method(code) employs an unstructured cell-centered method based on a conservative pressure-based finite-volume method with volume capturing method(CICSAM) in a volume of fluid(VOF) scheme for phase interface capturing As an application of the present method, the effects of wall adhesion are numerically simulated with the CSF model for a shallow pool of water located at the bottom of a cylindrical tank. Two different cases are computed, one in which the water wets the wall and one in which the water does not wet the wall. It is found that the present method simulates efficiently and accurately surface tension-dominant multiphase flows induced by wall adhesion.

• 한국임상수의학회지
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• 제17권2호
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• pp.381-387
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• 2000

Efficacy of a 1% solution of sodium carboxymethylcellulose (SCMC) infu7ed into the peritoneal cavity of dogs was evaluated for prevention of intraperitoneal adhesion, resulting from operations of the reproductive tract. Saline-treated deles (n = 5) were controls that underwent ventral midline celiotomy, and adhesions were cleated by incision and scraping about 5 cm segment of each uterine horn. Saline (7 ml/kg of body weight) was then infused into the peritoneal cavity. Others (n = 5) were treaded similarly to the saline-treated dogs. except that 1% SCMC :solution (7mH/kg of body weight) was infused into the peritoneal cavity. This group was studied to determine whether SCHC would prevent the adhesions in the peritoneal cavity, especially in the uterine horn model. Abdominal adhesions were evaluated and an adhesion severity score was assigned to each dog on the basis of severity of adhesions. At the time of necropsy. the mean adhesion score in the saline treated group was $2.65{\pm}0.22.$ In contrast, adhesion formation in the SCMC treated group was less ($mean score =1.70{\pm}0.26$). Statistic71 analysis was performed using the grouped t-test and paired t-test. A significanlty lower adhesion score was observed in dogs given SCMC than in the saline treated group (P<0.01). In summary, SCMC significantly reduced adhesion formation in the dog uterine horn model. The results of this study suggest that application of 1% SCMC solution, following various reproductive pelvic surgery, will present the adhesions.

• Tribology and Lubricants
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• 제39권1호
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• pp.8-12
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• 2023

This study presents a molecular simulation of adhesion control between carbon nanotube (CNT) and Ag thin film deposited on silicon substrate. Rough and flat Ag thin film models were prepared to investigate the effect of surface roughness on adhesion force. Heat treatment was applied to the models to modify the adhesion characteristics of the Ag/CNT interface based on thermal wetting. Simulation results showed that the heat treatment altered the Ag thin film morphology by thermal wetting, causing an increase in contact area of Ag/CNT interface and the adhesion force for both the flat and rough models changed. Despite the increase in contact area, the adhesion force of flat Ag/CNT interface decreased after the heat treatment because of plastic deformation of the Ag thin film. The result suggests that internal stress of the CNT induced by the substrate deformation contributes in reduction of adhesion. Contrarily, heat treatment to the rough model increases adhesion force because of the expanded contact area. The contact area is speculated to be more influential to the adhesion force rather than the internal stress of the CNT on the rough Ag thin film, because the CNT on the rough model contains internal stress regardless of the heat treatment. Therefore, as demonstrated by simulation results, the heat treatment can prevent delamination or wear of CNT coating on a rough metallic substrate by thermal wetting phenomena.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1744-1748
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• 2007

In this study, the Johnson-Kendall-Roberts (JKR) theory was combined with the instrumented indentation technique (IIT) to evaluate work of adhesion and modulus of elastomeric polymer. Indentation test was used to obtain the load-displacement data for contacts between Tungsten Carbide indenter and elastomeric polymer. And the JKR contact model, contrived to take viscoelastic effects of polymer into account, was applied to compensate the contact area and the elastic modulus which Hertzian contact model would underestimate and overestimate, respectively. Besides, we could obtain the thermodynamic work of adhesion by considering the surface energy in this contact model. In order to define the relation between JKR contact area and applied load without optical measuring of contact area, we used the relation between applied load and contact stiffness by examining the correlation between JKR contact area and stiffness through dimensional analysis with 14 kinds of elastomeric polymer. From this work, it could be demonstrated that the interfacial work of adhesion and elastic modulus of compliant polymer can be obtained from a simple instrumented indentation testing without area measurement, and provided as the main algorithm of compliant polymer characterization.

• 멤브레인
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• 제15권3호
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• pp.213-223
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• 2005

본 연구에서는 히알루론산나트륨/카르복시메틸셀룰로오스나트륨(HA/CMC)으로 구성된 유착방지 막을 제조하였고, 쥐에서 유착방지용에 대한 효과를 평가하였다. 유착방지 막은 HA/CMC 용액을 동결건조한 후 1-에틸-3-(3-디메틸아미노프로필)카보디이미드 (EDAC)로 가교하여 제조하였다. Sprague-Dawley쥐의 맹장/복벽 찰과상 모델에서 복부 중앙선 절개 후 장막과 복벽을 bone burr로 $1\times2\;(cm^2)$ 크기로 찰과상을 만들고, 상처 면 주위의 3곳을 봉합사로 고정시켰다. 상처난 장을 실험군의 경우 HA/CMC 막으로 덮어주었으며, 대조군은 아무처치도 하지 않은 상태로 복벽을 마주보게 하였다. 대조군의 대부분은 수술 후 7, 14, 21, 28일에 유착정도 3 이상을 나타내었고, 반면 실험군의 $60\~70\%$는 수술 후 14, 21, 28일에 유착정도 2 이하를 나타내었다. 이는 유착세기에서도 유사하였다. 일반적으로 유착정도와 유착세기는 수술 후 14일까지 점차 증가하였고, 수술 후 21일에는 거의 동일하거나 약간 증가하였으며, 28일째에는 감소하였다. 대조군은 유착정도와 유착세기, 유착면적에서 높은 수치를 나타내었다. 이 유착방지막은 수술 후 유착방지에서 좋은 임상결과를 나타낼 수 있을 것으로 기대된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.1255-1256
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• 2012

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.620-622
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• 2004

Mobility of an indoor wheeled robot is affected by adhesion force that is related to various floor conditions. When the adhesion force between driving wheels and the floor decreases suddenly, the robot has a slip state. In order to overcome this slip problem, optimal slip velocity must be decided for stable movement of wheeled robot. First of all, this paper shows that conventional PI control can not be applied to a wheeled robot of the light weigh. Secondly, reposed fuzzy logic applied by the Takagi-Sugeno model for the configuration of fuzzy sets. For the design of Takaki-Sugeno model and fuzzy rule, proposed algorithm uses FCM(Fuzzy c-mean clustering method) algorithm. In additionally, this algorithm controls recovered driving torque for the restrain the re-slip. The proposed fuzzy logic controller(FLC) is pretty useful with prevention of the slip phenomena through that compare fuzzy with PI control for the controller performance in the re-adhesion control strategy. These procedures are implemented using a Pioneer 2-DXE wheeled robot parameter.