• 폴리머
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• 제36권2호
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• pp.190-195
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• 2012

소프트 콘텍트 렌즈의 재질 별 계면학적 특성 및 유변학적 변화를 조사하여 렌즈 재료의 성분 설계에 기본 정보를 제시하고자 하였다. 눈물 단백질인 albumin과 IgG의 흡착량을 측정한 결과 하이드로젤의 표면 에너지가 증가함에 따라 점차 단백질 흡착량이 감소하는 것을 볼 수 있었다. Polydimethylsiloxane-polyvinylpyrrolidone(PDMS-PVP) 하이드로젤은 albumin과 IgG 흡착량이 가장 높았으며 poly(2-hydroxyethyl methacrylate)-polyvinylpyroolidone(HEMA-PVP)의 경우 albumin의 흡착량은 매우 미미한 것으로 나타났다. 일정한 수직항력 하에서의 하이드로젤의 토크는 실리콘 재질인 PDMS-PVP의 경우 HEMA계열보다 약 5배 이상 크게 측정된 것을 볼 수 있었다. 흥미로운 것은 단백질 흡착량이 적은 HEMA계열 하이드로젤의 경우 실리콘 계열 하이드로젤보다 인공 눈물 내 거동 시 마찰계수가 오히려 더 큰 것을 알 수 있었다. 인공눈물 내의 하이드로젤의 거동은 단백질 흡착으로 인한 윤활 효과 외에도 하이드로 젤 고유의 구조와 회전하는 계면의 성질에 큰 영향을 받는 것을 알 수 있었다.

• 한국수소및신에너지학회논문집
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• 제27권2호
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• pp.176-181
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• 2016

Recent years, supercapacitors have been attracting a growing attention as an efficient energy storage, due to their long-lifetime, device reliability, simple device structure and operation mechanism and, most importantly, high power density. Along with the increasing interest in flexible/stretchable electronics, the supercapacitors with compatible mechanical properties have been also required. A eutectic gallium-indium (EGaIn) liquid metal could be a strong candidate as a soft electrode material of the supercapacitors because of its insulating surface oxide layer for electric double layer formation. Here, we report the electrochemical study on the charging/reaction process at the interface of EGaIn liquid metal and electrolyte. Numerical fitting of the charging current curves provides the capacitance of EGaIn/insulating layer/electrolyte (${\sim}38F/m^2$). This value is two orders of magnitude higher than a capacitance of a general metal electrode/electrolyte interface.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1999년도 유체기계 연구개발 발표회 논문집
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• pp.301-308
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• 1999

The present study investigates numerically particle laden flow through compressor cascades and a rocket nozzle. Engines are affected by various particles which are suspending in the atmosphere. Especially in the case of aircraft aviating in volcanic, industrial and desert region including many particles, each components of engine system are damaged severely. That damage modes are erosion of compressor blading and rotor path components, partial or total blockage of cooling passage and engine control system degradation. Numerical prediction and experimental data, erosion rates are predicted for two materials - ceramic, soft metal - on compressor blade surface. Aluminum oxide ($Al_2O_3$) Particles included in solid rocket propelant make ablative the rocket motor nozzle and imped the expansion processes of propulsion. By the definition of particle deposition efficiency, characteristics of particles impaction are considered quantitatively Stoke number is defined over the various particle sizes and particle trajectories are treated by Lagrangian approach. Particle stability is considered by definition of Weber number in rocket nozzle and particle breakup and evaporation is simulated in a rocket nozzle.

• 한국지반환경공학회 논문집
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• 제8권1호
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• pp.27-32
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• 2007

연약지반과 관련된 공사에서는 표층을 개량하여 교통성을 확보하여야 한다. 이를 위해 고화재를 이용한 지반개량공법이 이용되고 있으나, 지금까지 사용된 고화재는 시멘트를 개량한 제품을 이용하였다. 그러나 현재 폐기물로 인정되는 굴패각의 재활용 기회를 확대하기 위해 굴패각을 이용한 고화재를 개발하여 사용하고 있다. 본 연구에서는 준설토를 대상으로 굴패각 고화재의 혼입율, 함수비, 양생일에 따른 강도 특성을 분석하여 굴패각 고화재의 역학적 특성이 우수함을 확인하였다.

• 한국전기전자재료학회논문지
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• 제13권7호
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• pp.568-574
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• 2000

We have been optimized tungsten(W) plug CMP(chemical mechanical polishing) characteristics using two different kinds of component of slurry and two different kinds of pad which have different hardness. The comparison of oxide film roughness on around W plug after polishing has been carried out. And W plug recess for consumable sets and dishing effect at dense area according to the rate of over-polishing has been investigated. Also the analysis of residue on surface after cleaning have been performed. As a experimental result we have concluded that the consumable set of slurry A and hard pad was good for W plug CMP process. After decreasing the rate of chemical reaction of silica slurry and adding two step buffering we could reduce the expanding of W plug void however we are still recognizing to need a more development for those kinds of CMP consumables.

• 한국구조물진단유지관리공학회 논문집
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• 제7권3호
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• pp.115-124
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• 2003

본 연구에서는 공사중 계측 결과와 유지관리 계측 결과를 토대로 다양한 분석방법을 통하여 터널의 변위와 응력 등을 분석하였으며, 지반조건이 비교적 연약한 풍화대를 통과하는 지하철 터널의 거동을 분석하여 터널 라이닝의 역학적 특성을 분석하였다. 공사중 계측결과 상부 및 하부 반단면 굴착 완료시의 계측결과를 단순화하여 터널 굴착시 천단침하가 지표침하와 내공변위보다 크다는 것을 확인하였으며, 천단침하와 천단숏크리트 라이닝응력이 역해석 시에 가장 많이 사용되는 계측항목임을 알 수 있었다. 그리고, 간극수압 분석결과를 통해 배수형 터널에 설계시 적용되고 있는 잔류수압의 타당성을 분석하였다.

• 비파괴검사학회지
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• 제30권3호
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• pp.181-193
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• 2010

The paper presents an alternative way to classical stereocorrelation. First, 2D image processing of random patterns is described. Sub-pixel displacements are determined using phase analysis. Then distortion evaluation is presented. The distortion is identified without any assumption on the lens model because of the use of a grid technique approach. Last, shape measurement and shape variation is caught by fringe projection. Analysis is based on two pin-hole assumptions for the video-projector and the camera. Then, fringe projection is coupled to in-plane displacement to give rise to 3D measurement set-up. Metrological characterization shows a resolution comparable to classical (stereo) correlation technique ($1/100^{th}$ pixel). Spatial resolution seems to be an advantage of the method, because of the use of temporal phase stepping (shape measurement, 1 pixel) and windowed Fourier transform (in plane displacements measurement, 9 pixels). Two examples are given. First one is the study of skin properties; second one is a study on leather fabric. In both cases, results are convincing, and have been exploited to give mechanical interpretation.

• Journal of Oral Medicine and Pain
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• 제46권3호
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• pp.84-87
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• 2021

Morsicatio buccarum is a condition caused by chronic cheek biting. It means frictional hyperkeratosis by repetitive cheek biting, which may be associated with obsessive compulsion. Clinically it presents as rough, shaggy, whitish, often peeling surface. We report a 9-year-old female patient who complained oral ulceration on both buccal mucosa. The initial diagnosis was oral candidiasis because of whitish plaques which were peeled off. Topical antifungal agent was ineffective and the symptom did not disappear. By incisional biopsy, she was diagnosed with morsicatio buccarum. A soft oral appliance was placed in the patient's oral cavity. Although morsicatio buccarum improved significantly when the appliance was used, the oral lesion had a tendency to recur, when the patient stopped using the appliance. In case of recurrence, cognitive behavioral therapy for obsessive-compulsive disorder is needed for the fundamental treatment.

• 대한물리의학회지
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• 제16권2호
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• pp.63-70
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• 2021

PURPOSE: This study aimed to analyze the factors influencing the improvement of global synkinesis (GS) and gait in stroke patients by the weight shift exercise. METHODS: Twenty stroke patients were randomly assigned to experimental group I (n = 10) and experimental group II (n = 10). In experimental group I, weight shift with upper extremity exercises in a standing position were mediated and in experimental group II, upper extremity exercises in a standing position were mediated. These interventions were conducted in both groups for three sessions per week, 30 minutes per session over four weeks. Before the interventions, leg GS was measured using surface electromyography and the 10m walk test (10MWT). The same parameters were measured four weeks later. RESULTS: The GS and 10MWT of the experimental group I showed that there was a statistically significant difference between dorsiflexion (p < .05) and plantarflexion (p < .01) and 10MWT (p < .01). In experimental group II, there was a statistically significant difference only in 10MWT (p < .01). The comparison between the changes in both groups showed that in the case of GS, there was a statistically significant difference in the dorsiflexion (p < .01) and plantarflexion (p < .05), and in the 10MWT too (p < .05). CONCLUSION: GS of the lower extremities was decreased by improving posture control and enlarging soft tissues due to the symmetrical weight shift in experimental group I, which turned out to be effective in improving the gait speed.

• 한국임상수의학회지
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• 제36권2호
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• pp.119-122
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• 2019

The prevailing discipline notes that primary pulmonary angiosarcoma is an extremely rare malignant tumor with almost grave prognosis when presented in a dog. No cases have been reported earlier as occurring in dogs. This is the first time we are reporting a case of primary lung angiosarcoma in a 12-year-old Yorkshire terrier breed dog, that will explore the clinical as well as histopathological features of the tumor as noted in a dog. In this case, radiography revealed a well-defined large soft tissue mass in the caudo-dorsal lung field across the left hemi-thorax. After necropsy, it is noted that the lung was found to have the blood-filled nodular lesions on its surface, as determined with no such lesions on other organs. Upon the histological examination, it showed the presence of an extensive necrotic hemorrhage with anastomosing vascular space. Later, the immunohistochemistry showed strongly positive CD31 cells confirming the endothelial origin of the tumor. This is the first report of canine primary lung angiosarcoma in the Republic of Korea.