• 대한두경부종양학회지
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• 제26권2호
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• pp.256-258
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• 2010

Although liposarcoma is the second most common soft tissue sarcoma in adults, the incidence of liposarcoma in the head and neck is low. The histologic nature of liposarcoma is correlated clinically with treatment outcome, but histologic classification of liposarcoma is controversial. Well-differentiated liposarcoma and atypical lipoma are pathologic synonyms because they are identical lesions both morphologically and karyotypically. They represent the lowest grade lesions in the spectrum of liposarcoma. The terms "atypical lipoma" were introduced specifically to describe well-differentiated liposarcomas occurring in the extremities, because of their better prognosis in comparison with their retroperitoneal counterparts. We present 1 case of atypical lipomatous tumor of the neck.

• 대한두경부종양학회지
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• 제33권1호
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• pp.57-59
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• 2017

A non-recurrent laryngeal nerve on the left side is a rare anomaly which is reported in 0.04% and it is associated with abnormal developments of the aortic arch during embryogenesis. Although the possibility is extremely low, it is important to consider the possible existence of a non-recurrent laryngeal nerve to prevent a nerve injury during thyroidectomy. We experienced a 42 year-old male with left thyroid papillary cancer who had right side aortic arch and aberrant left subclavian artery. Even though we found that this patient had a recurrent laryngeal nerve, we present this case of the right aortic arch with an aberrant left subclavian artery variation with a brief review of literature.

• 대한두경부종양학회지
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• 제32권2호
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• pp.35-39
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• 2016

Castleman's disease (CD) is an uncommon lymphoproliferative disorder. The disease entity is classified into 2 clinical subtypes, unicentric and multicentric type. Prevalence of lymphoid malignancy in multicentric CD (MCD) is very low. In this case, we report a case of 77 years old woman who developed high fever and swelling in both side of her neck. Neck lymph node biopsy revealed plasma cell hyperplasia. Patient's symptom was subsided after treatment with Dexamethasone. Three months later, multiple lymph node enlargement was developed in abdomen and neck area again. Repeated neck lymph node biopsy confirmed diffuse large B cell lymphoma. The patient started chemotherapy.

• 한국분무공학회지
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• 제28권2호
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• pp.97-104
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• 2023

A sprinkler is a fire suppression system that extinguishes combustible materials in the early stages of a fire, creating a spray. However, spray formation method of the sprinkler can result in an uneven distribution of water spray on the surface of combustible materials. It is necessary to ensure a consistent water flux density regardless of the spray direction and angle. In this study, the water flux distribution was analyzed for the various types of sprinkler head: circular, flush, pendent, and upright types. All sprinkler heads have a K-factor of 80 LPM/(0.1MPa)^0.5. In this study, water collection cubes were used to examine the water flux distribution. The upright type sprinkler head showed a low standard deviation in total sprayed area, indicating a high level of uniformity. The upright type head showed the lowest standard deviation in the radial direction, and also showed the lowest standard deviation in the azimuthal direction. Upright sprinkler head has no obstructing structure along the path of droplets after they are generated. For this reason, upright sprinkler head showed the most uniform water flux distribution on the floor.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제29회 춘계학술대회
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• pp.339-344
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• 1999

In this paper, the hardness and wear characteristics of the head hardened rail, which is made by thermite and gas pressure weldings have been presented. In general, the wear rate of the gas pressure welded rail is high and uniform compared with that of thermite welded rail. The results indicate that HH 370 welded rail shows stable in hardness and low wear rate compared with other two welded rails. The hardness of head hardened rails shows uniformly distributed along the welded zone, thermally affected zone and a base matrix.

• 대한두경부종양학회지
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• 제31권2호
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• pp.46-48
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• 2015

Cystadenocarcinoma of salivary gland is an rare, slow-growing, low-grade malignant neoplasm characterized by cysts and papillary endocystic projections. Major locations of this tumor are parotid glands, and minor salivary glands, while occurrence in submandibular gland is extremely rare. Only few cases have been reported in the literatures. Cystadenicarcinoma behaves in an indolent manner and recurrence is rarely occured, surgical complete excision is considered treatment of choice. We experienced a case of cystadenocarcinoma arising from submandibular gland, so we report this case with a review of literature.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.322-326
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• 2001

Hard disk drive(HDD) consists of a head/slider system which flies over the magnetic disk at an extremely low height. As the density of HDD increases the flying height of the head needs to be decreased. This increases the chance for contact between the slider and the disk. This paper addresses some key issues related to surface failure characteristics of HDD. It is shown that flying behavior of the slider during contact-start-stop cycle can be analyzed based on different regimes of air film lubrication, experimental methods for identifying the underlying mechanisms and improving the reliability of HDD are discussed.

• KSTLE International Journal
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• 제3권2호
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• pp.114-118
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• 2002

In this work, head-disk interactions are studied when flying height becomes lower than laser bump height on the landing zone of a disk. With the reduction of the spinning speed in a spin stand, the flying height is decreased under the height of laser bumps. Conventional and padded pico sliders sweep between landing Bone and data zone and, then, the dynamic behavior of the pico sliders and head-disk impacts are investigated using AE and stiction/friction signals. After 200n cycle-sweep tests, bearing analysis and AFM analysis indicate that there are some signs of wear and plastic deformation in the landing zone of a disk, although AE and stiction/friction signals are not significantly changed during the sweep tests. The experimental results of this paper suggest that in CSS tests at component level, more rigorous examination methods of wear and plastic deformation might be necessary as flying height becomes getting lower.

• 한국정밀공학회지
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• 제25권9호
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• pp.116-125
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• 2008

Inkjet printing technology with a drop-on-demand (DOD) inkget head technology has been recognized as one of versatile and low cost manufacturing tools in the electronics industry. Concerned with control of driving signal, however, general strategy to optimize jetting stability has not been understood well, because of the inherent complex multi-physics nature in inkjet phenomena. Motivated by this, present study investigates the effect of driving waveforms of piezoelectric head on jetting characteristics of DOD inkjet system focused on jetting stability with phase matching of pressure waves in the print head. The results show that velocities and volumes of the ink jetted droplets were linear relations with the driving signal's maximum voltage, while periodic behaviors are observed with the driving signal's pulse widths.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1444-1449
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• 2007

Inkjet printing technology with a drop-on-demand (DOD) inkjet head technology has been recognized as one of versatile and low cost manufacturing tools in the electronics industry. Concerned with control of driving signal, however, general strategy to optimize jetting stability has not been understood well, because of the inherent complex multi-physics nature in inkjet phenomena. Motivated by this, present study investigates the effect of driving waveforms of piezoelectric head on jetting characteristics of DOD inkjet system focused on jetting stability with phase matching of pressure waves in the print head. The results show that velocities and volumes of the ink jetted droplets were linear relations with the driving signal's maximum voltage, while periodic behaviors are observed with the driving signal's pulse widths.