• Tribology and Lubricants
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• v.18 no.4
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• pp.305-311
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• 2002

Three different kinds of brake discs including two coated brake discs and one steel disc were tested under the same experimental conditions on a reduced scale braking test bench. A braking test bench was specially designed to analyse thermo-mechanical and frictional behaviors of two types of brake with different sizes in stop and hold braking modes. Plasma spray coating technique was also used to coat the discs with ceramic powder. During the test four commercial brake pads were coupled with discs. Ceramic coated discs showed good stability in friction coefficient at high speed and high energy braking conditions. But they caused large wear loss of pad mass compared with the steel disc. It was shown that thermal barrier effect in ceramic coated discs adjusted the thermal partition between pad and disc. For a steel disc. it showed fluctuating friction coefficient at high speed but small wear loss of pad mass compared with ceramic coated discs.

• Investigative Magnetic Resonance Imaging
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• v.12 no.2
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• pp.197-200
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• 2008

Intracapsular and paraarticular chondroma is a rare benign lesion of the large joints (mostly the knee). We report a case of intracapsular and paraarticular chondroma in the infrapatellar Hoffa’s fat pad that presented as a painful palpable mass in 15-year-old woman. A physical examination revealed a firm, movable and tender mass in the infrapatellar area. Magnetic resonance images showed an ovoid, well-defined, soft tissue mass with focal calcification in the infrapatellar fat pad. The final pathology revealed an intracapsular and paraarticular chondroma.

• Journal of Korean Foot and Ankle Society
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• v.19 no.4
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• pp.188-192
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• 2015

Purpose: The purpose of this study is to provide Korean data on heel pad thickness according to age, gender, underlying disease, occupation, and body mass index (BMI). Materials and Methods: A retrospective study was conducted on 670 patients who underwent foot lateral plain radiography and magnetic resonance imaging (MRI) between January 2010 and July 2014. Through measurements of heel pad thickness, the usefulness and accuracy of foot lateral plain radiography was evaluated, and the mean Korean heel pad thickness in the weight-bearing and non-weight-bearing conditions was also evaluated according to age, gender, underlying disease, occupation, and BMI. Results: The 670 subjects with a mean age of 44 years (range, 12 to 84 years) consisted of 420 males and 250 females. The difference in heel pad thickness between non-weight-bearing foot lateral plain radiography and MRI was 0.69 mm. The heel pad thickness did not show a significant difference with age (p=0.08) and the presence of diabetes (p=0.09). With the increase in the Tegner score, the thickness of the heel pad increased (p=0.035), and subjects with a higher BMI had a thicker heel pad (p=0.03). The compressibility of the heel pad thickness showed no correlation with gender, diabetes, and Tegner score. Compressibility also increased with the increase in age and body weight. Conclusion: The mean Korean heel pad thickness measured through non-weight-bearing foot lateral plain radiography was 18.79 mm. The heel pad thickness increased with increasing BMI; however, age and diabetes did not show significant correlation. The compressibility of heel pad increased with the increase in age.

• Journal of Korean Foot and Ankle Society
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• v.8 no.1
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• pp.22-25
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• 2004

Purpose: The heel fat pad has a unique structure that is important for its shock absorbing function. Loss of elasticity and change in the thickness of the heel pad have been suggested as cause of heel pain. The present study shows the relationship between the thickness of heel fat pad and age, sex, obesity and plantar heel pain. Materials and Methods: A study of heel pad thickness using plain lateral radiographs, unloaded by body weight, was carried out on 66 patients with plantar heel pain and 326 normal subjects. The population was divided into two or three groups according to their age, sex, body mass index, and the presence of symptom. We evaluated the differences in heel pad thickness between groups, and the relationship between BMI and Sex and Age was also determined, using statistically analytic method by SPSS version 10.1 program. Results: Heel pad thickness was greater in the subject over 40 years old (p<0.001), and in the overweight (p<0.001), and male heel pad was thicker than female (p<0.001). But there was no statistically significant difference for heel pad thickness between normal subject and plantar heel pain group. Conclusion: In this study, we found that there is a relationship between heel pad thickness and age, sex, and obesity. But we could not show that the difference of heel pad thickness is contributing factor to plantar heel pain. Although it could not be proved statistically, we believe that a change of heel pad thickness play a role in the development of heel pain. So we are planning to assess a relationship of heel pad elasticity and thickness and plantar heel pain again with prospective study method on the basis of the results of this study.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.924-929
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• 2001

The flying height of contact slider is determined by vertical and pitching motions of slider. This paper performed the computer simulation for flying height change of contact slider. It is changed by many parameters, contact stiffness, contact damping, air bearing stiffness ratio, a location of mass center, and so on. Computer simulation is performed for knowing for what change of these parameters influences in flying height of contact slider. Disk surface is modeled in harmonic wave with from 10㎑ to 600㎑. Tri-pad slider is modeled in that contact slider has 2-DOF motion (vertical motion, pitching motion). Tri-pad contact slider is analyzed by numerical analysis method in computer simulation.

• Journal of the Microelectronics and Packaging Society
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• v.5 no.2
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• pp.37-48
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• 1998

The popcorn cracking phenomena in plastic IC packages during reflow soldering are investigated by considering the heat transfer and moisture diffusion through the epoxy molding compound(EMC) along with the mechanics of interface delamination. Heat transfer and moisture diffusion through EMC under die pad are analyzed by finite difference method (FDM)during the pre-conditioning and subsequent reflow soldiering pro-cess and the amounts of moisture mass and vapor pressure at delaminated die pad/ EMC interface are calculated as a function of the reflow soldering time. The energy release rate stress intensity factor and phase angle were obtained under various loading conditions which are thermal crack face vapor pressure and mixed loadings. It was shown that thermal loading was the main driving force for the crack propagation for small crack lengths but vapor pressure loading played more significant role as crack grew.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.44 no.1
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• pp.29-33
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• 2018

Sinonasal mucosal melanoma (SNMM) in the maxillary sinus is a rare disease condition. Compared to oral mucosal melanoma, SNMM has a bulky, exophytic, and polypoid appearance, is weakly pigmented, and associated with unspecific symptoms. Due to these features, SNMM in the maxillary sinus has been misdiagnosed as nasal polyps and chronic sinusitis. In this case report, we described SNMM occurring in the right maxillary sinus simulated as a cystic or benign lesion. Cortical bone thinning and expansion were observed around the mass. The excised soft mass was encapsulated and weakly pigmented. The mass was clearly excised and covered with a pedicled buccal fat pad graft. Diagnosis using immunohistochemistry with S-100 and homatropine methylbromide-45 (HMB-45) is critical for proper treatment.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.13 no.2
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• pp.153-159
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• 1991

The use of the autogenous free fat is a well-known procedure to fill in superficial depressions resulting from the traumatic or congenital defects. The major donor site for this procedure was the abdominal subcutaneous fat or buttocks. In 1977, Egyedi was the first to report the use of the buccal fat pad as a pedicled graft. The buccal fat pad is a structure usually considered to be a nuisance when encountered in intraoral procedures such as facial bone osteotomies, elevation of buccal falp, or procedures on Stensen's duct. In these operations, appearance of the buccal fat pad complicates surgical exposure. The buccal fat pad is a lobulated convex mass of fatty tissue covered by a very delicate membrane, and is described as having a body from which four processes extend. These projection serve as a filling material between the various muscular structures in the area. Recently malar depression was augmented with the pedicled buccal fat pad in 3 cases, and it was used for the reconstruction of the nasolabial fold in one case.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.8
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• pp.104-109
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• 2020

Recently, vibration and noise have become an important issue in the auto industry. Asphalt vibration damping pads are used to reduce the noise and vibration of automobile bodies, and asphalt is used for many mass-produced parts due to its simple attachment process and low processing costs. In this study, the self-adhesion of asphalt pads using Joule heating was evaluated. To create the asphalt pad for the experiment, the asphalt pad was molded into a specific thickness by using SGACC material and rubber used in the vehicle body as a main component and a modified resin and filler. The SGACC material was 200 mm in length, 200 mm in width, and 0.7 mm in thickness. The asphalt pad was 200 mm in length, 100 mm in width, and 3 mm in thickness. The equipment was composed of a TR (Transformer) DC254kVA and a TC (Time controller) for a current of up to 20,000 A. The current for the Joule heating was set to 7.0 kA and a 3/1 cycle, for which the adhesion of the asphalt pad over the current flow time was evaluated.

• Tribology and Lubricants
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• v.29 no.2
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• pp.98-104
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• 2013

Cu-matrix-sintered brake pads and heat-resistant low-alloy steel are commonly applied to basic brake systems in high-energy moving machines. We analyzed how the tribological characteristics are influenced by the inertial mass. A high inertial mass decreased the friction coefficient by about 15% compared to a low inertial mass under all velocity conditions. The wear rates of the friction materials increased with the inertial mass. Thus, the inertial mass influences the friction coefficient and wear rate of the friction materials and disk but not the friction stability.