• Polymer(Korea)
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• v.36 no.2
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• pp.190-195
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• 2012

Interfacial and rheological properties of selected hydrogel formulations were studied to understand the contact-lens comfort in end use. It was concluded that protein adsorption from aqueous solution decreased monotonically with increasing surface energy (water wettability) of tested hydrogels. Also, it has revealed that friction coefficient of polydimethylsiloxane-polyvinylpyrrolidone (PDMS-PVP) was significantly larger that 2-hydroxyethyl methacrylate (HEMA) based hydrogels. Interestingly, in artificial tear solution, friction coefficients of HEMA based hydrogels were larger than silicone hydrogels.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.2
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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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• 1999.12a
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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.

• Journal of the Korean GEO-environmental Society
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• v.8 no.1
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• pp.27-32
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• 2007

Trafficability for construction equipments in soft ground should be secured by improving the surface course. For this situation, the ground improvement technique has been used with stiffening agent, but the improvement cement has been mostly used so far. However, oyster shell has been developed and used as the stiffening agent to expand the chance of recycling oyster shell, which is regarded as solid waste. In this research, it was confirmed mechanical characteristics of oyster shell as stiffening agent by analyzing the strength characteristic such as mixing rates, water contents, and curing days of that to the dredging soil.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.7
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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.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.3
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• pp.115-124
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• 2003

In this study, the relationships between the displacement and stress of the tunnel using various analysis methods were compared with monitoring results carried out during construction and maintenance monitoring. The behavior of tunnel were measured in the subway tunnel passing comparative soft the weathering and analyzed both security and mechanical characteristics of the tunnel lining. With the results of simplified monitoring observed in top heading and bench excavation tunnel, it is confirmed that the crown settlement is larger than the surface settlement. it is interesting to note that the crown settlement and the crown shotcrete lining stress are widely used monitoring items for the back analysis. It is analyzed that the residual water pressure applied in the drainage type tunnel is reasonable.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.3
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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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• v.46 no.3
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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.

• Journal of the Korean Society of Physical Medicine
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• v.16 no.2
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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.

• Journal of Veterinary Clinics
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• v.36 no.2
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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.