• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.92-98
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• 2008

A combination of the instrumented indentation and 3D morphology measurement has been tried in order to perform a real-time property measurement of degraded materials in gas pipelines; three-dimensional indent morphologies were recorded using a reflective laser scanner after a series of insturmented indentations on three metallic specimens. Dimensions of the permanent deformation zone and contact boundary were analyzed from the cross-sectional profile over an remnant indent and used for estimating yield strength and hardness, respectively. Estimated yield strength was comparable with that from uniaxial tensile test and actual hardness implying material pile-up effects was lower than the calculated value from indentation curve by $20{\sim}30%$. It means that this 3D image analysis can explain the material pile-up effects on the contact properties. Additionally, a combined system of indentation and laser sensor was newly designed by modifying a shape of the indentation loading fixture.

• Korean Journal of Head & Neck Oncology
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• v.33 no.2
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• pp.95-99
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• 2017

Schwannoma, also known as a neurilemmomas or neurinomas, is benign peripheral nerve sheath tumors arising from the Schwann cells. About 25~45 % of all schwannomas are found in the head and neck region, and the majority are found in the parapharyngeal space. Schwannoma of the larynx is very rare with an incidence of 0.1~1.5% in all benign laryngeal tumors. Recently, we experienced a case of a pedunculated schwannoma arising from the left aryepiglottic fold in a 80-year-old patient. The tumor was completely excised under direct laryngoscopy with the use of a $CO_2$ laser and subsequently confirmed as schwannoma. So, we report this case with a review of the literatures.

• Journal of the Korean Society of Combustion
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• v.4 no.1
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• pp.49-57
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• 1999

An experimental study on double-concentric diffusion flame has been carried out in order to investigate the shape, the flame length, and the other characteristics of the flame. Flow visualization of the flame by the $TiO_2$ particles and also the emission measurements are conducted. The commercial grade LP gases are used as fuel. The inverse diffusion flames are formed at the center when the central air flow rate is about 0.1 L/min. With a larger flow rate of the central air jet than 0.2 L/min the flame turns to be an annular-shaped flame, which is very bright. When the central air flow rate increases over 2.4 L/min, the flame turns to blue and the flame tips are opened because of the lifting of the inner part of the flame. Because of this lifting and the incomplete combustion, the CO emission increases abruptly from 25 ppm to more than 150 ppm. On the contrary, the NOx emission is decreased.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.658-663
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• 2003

A process of 3-D stereo particle image velocimetry(PIV)was developed for the measurement of an illuminated sliced section field of 3-D complex flows. The present method includes modeling of camera by a calibrator based on the homogeneous coordinate system, transformation of the oblique-angled image to the right-angled image, identification of 2-D velocity vectors by 2-D cross-correlation equation, stereo matching of 2-D velocity vectors of two cameras, accurate calculation of 3-D velocity vectors by homogeneous coordinate system, removal of error vectors by a statistical method followed by a continuity equation criteria, and finally 3-D display as the post processing. An experimental system was also used for the application of the proposed method. Two high speed digital CCD cameras and an Argon-Ion Laser for the illumination were adopted to clarify the time-dependent characteristics of the leading edge extension(LEX) in a highly swept shape applied to a delta wing found in modern air-fighters.

• Korean Journal of Head & Neck Oncology
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• v.35 no.2
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• pp.71-75
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• 2019

Inflammatory myofibrolastic tumor (IMT) is a rare borderline neoplasm. It frequently occurs in the lung but occasionally occurs in extrapulmonary sites such as the genitourinary tract, gastrointestinal tract, breast, salivary glands, sinonasal tract, orbit, and the central nervous system. Laryngeal involvement of IMT is very rare. A 61-year-old woman who complained of hoarseness persisting for 3 months visited our hospital. Laryngoscopy showed an elevated lesion in the right true vocal cord. Incisional biopsy was confirmed as larygeal inflammatory myofibrolastic tumor. We performed a transoral excision with CO₂ LASER under suspension examination. Regional recurrence or distant metastasis was not observed after 9 months of follow-up. Herein we report a case of larygeal inflammatory myofibrolastic tumor that was treated with surgery alone, with a literature review.

• Tuberculosis and Respiratory Diseases
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• v.78 no.2
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• pp.106-111
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• 2015

Tracheal hemangioma is a rare benign vascular tumor in adults. We reported a case of massive hemoptysis caused by a cavernous hemangioma in a 75-year-old man. This is the first report, to our knowledge, of a tracheal cavernous hemangioma that presented with massive hemoptysis. The lesion was removed with a $CO_2$ laser under rigid laryngoscopy. Endovascular tumors, such as tracheobronchial hemangiomas, should be considered a diagnostic option in cases of massive hemoptysis without a significant underlying lung lesion.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.32 no.2
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• pp.94-97
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• 2021

Muscle tension dysphonia (MTD) is a voice disorder characterized by excessive tension of the laryngeal muscles during phonation. Voice therapy is the gold standard of treatment for MTD. However, patients with MTD do not always respond to voice therapy. Multidisciplinary approaches have been attempted to treat intractable MTD such as lidocaine instillation, lidocaine injection to recurrent laryngeal nerve, botox injection and excision of false ventricle using CO₂ laser. Recently, injection laryngoplasty is suggested that assists in more efficient phonation and voice therapy to MTD patients. A patient with intractable MTD underwent lidocaine injection and injection laryngoplasty showed improved voice quality and remained stable until postoperative 3 months without any complications.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.32 no.2
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• pp.104-108
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• 2021

The etiology of laryngeal hemangioma is unclear, and it is classified into infant and adult types. The former is capillary hemangioma and relatively common, the latter is cavernous type and very rare. The adult laryngeal hemangioma mainly occurs in supraglottis and glottis. A 75-year-old man came to our clinic with a voice change that started four months ago. The laryngoscopic finding showed that the surface of oval-shaped mass is covered with turbid exudates. We performed the laryngeal microsurgery with CO₂ laser. The mass was pathologically proven as cavernous hemangioma. We report a very rare and didactic case with review of relevant literature.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.1
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• pp.67-71
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• 2010

Impingement of a high power laser pulse (above 1 GW/$cm^2$) on a metal foil causes its ablation, which is characterized by a rapid expulsion of matter and the initiation of a strong shock wave inside the solid metal. The shock propagates through the foil and reverberates on the rear side, causing its deformation and microparticle ejection, which were deposited on the foil prior to ablation. Based on this principle, we are developing a new drug delivery system - Biolistic gun. Current study is focused on the controllability, stability, efficiency of the system, and characterization of the penetration shapes in various conditions. We have tested the system by applying direct and confined ablation. Several different media combinations were used for confinement-BK7 glass, water, BK7 glass with water, and succulent jelly(ultrasono jelly, RHAPAPHRM). Biological tissue was replicated by a 3% gelatin solution. Present data shows that the confinement results in enhancement of penetration shape reached by 5 um cobalt microparticles. Based on the analysis of the experimental results we observe that the penetration shape of microparticles can be controlled by adjusting the thickness of confinement media.

• The Journal of Advanced Prosthodontics
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• v.5 no.4
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• pp.471-478
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• 2013

PURPOSE. The aim of the study was to evaluate the effect of annealing on the nanostructure and hardness of Co-Cr metal ceramic samples that were fabricated with a direct metal laser sintering (DMLS) technique. MATERIALS AND METHODS. Five groups of Co-Cr dental alloy samples were manufactured in a rectangular form measuring $4{\times}2{\times}2$ mm. Samples fabricated by a conventional casting technique (Group I) and prefabricated milling blanks (Group II) were examined as conventional technique groups. The DMLS samples were randomly divided into three groups as not annealed (Group III), annealed in argon atmosphere (Group IV), or annealed in oxygen atmosphere (Group V). The nanostructure was examined with the small-angle X-ray scattering method. The Rockwell hardness test was used to measure the hardness changes in each group, and the means and standard deviations were statistically analyzed by one-way ANOVA for comparison of continuous variables and Tukey's HSD test was used for post hoc analysis. P values of <.05 were accepted as statistically significant. RESULTS. The general nanostructures of the samples were composed of small spherical entities stacked atop one another in dendritic form. All groups also displayed different hardness values depending on the manufacturing technique. The annealing procedure and environment directly affected both the nanostructure and hardness of the Co-Cr alloy. Group III exhibited a non-homogeneous structure and increased hardness ($48.16{\pm}3.02$ HRC) because the annealing process was incomplete and the inner stress was not relieved. Annealing in argon atmosphere of Group IV not only relieved the inner stresses but also decreased the hardness ($27.40{\pm}3.98$ HRC). The results of fitting function presented that Group IV was the most homogeneous product as the minimum bilayer thickness was measured (7.11 ${\AA}$). CONCLUSION. After the manufacturing with DMLS technique, annealing in argon atmosphere is an essential process for Co-Cr metal ceramic substructures. The dentists should be familiar with the materials that are used in clinic for prosthodontics treatments.