• International Journal of Precision Engineering and Manufacturing
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• 제9권4호
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• pp.22-25
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• 2008

The dynamic response of the head arm assembly (HAA) of a hard disk drive to an impact load was obtained from a 3D non-linear finite element model using ANSYS/LS-DYNA and from experiments using a modified levitation mass method (LMM). In the finite element model, the impact load was created by modeling the mass as a rigid body and making it collide with the HAA. The velocity, displacement, acceleration, and inertial force of the mass were then obtained from the time history data of the finite element analysis. In the LMM, a mass that was levitated with an aerostatic linear bearing, and hence encountered negligible friction, was made to collide with the actuator arm, resulting in a dynamic bending test for the arm. During the collision, the Doppler frequency shift of the laser beam reflected from the mass was accurately measured with an optical interferometer. The velocity, displacement, acceleration, and inertial force of the mass were accurately calculated from the measured time-varying Doppler frequency shift. A good correlation between the experimental data and FEA results was observed. The FEA was also used to investigate the dynamic response of the HAA to impact by different masses.

• 대한두경부종양학회지
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• 제36권2호
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• pp.27-31
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• 2020

Neck mass has various etiologies, including inflammatory, congenital, neoplastic causes. The IgG4-related disease can cause symptoms in the head and neck areas with an inflammatory neck mass. It also shows clinical and pathological findings from inflammation caused by immune reactions, such as lymphocyte and plasma cell infiltration, storiform fibrosis, obliteration phlebitis, and invigorated serum IgG4 levels. The treatment guideline has not been established and still under debate, but systemic glucocorticoid seems to be effective in the most cases. In this brief report, a 48-year-old male patient presented with voice change for 3 weeks. Left side paramedian vocal fold palsy was observed in the flexible laryngoscopy. About 2.5×2.0×1.2cm size, heterogeneously enhanced neck mass with irregular margin encasing left carotid artery was noted on preoperative contrast enhanced neck CT scan, and it was suspicious of left carotid body tumor. The pathology shows IgG4-related disease rather than carotid body tumors. We report this case of IgG4-related disease, which can be misdiagnosed to carotid body tumors.

• Nuclear Engineering and Technology
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• 제48권4호
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• pp.906-914
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• 2016

We investigated the heat load imposed on the lower head of a reactor vessel by the natural convection of the oxide pool in a severe accident. Mass transfer experiments using a $CuSO_4-H_2SO_4$ electroplating system were performed based on the analogy between heat and mass transfer. The $Ra^{\prime}_H$ of $10^{14}$ order was achieved with a facility height of only 0.1 m. Three different volumetric heat sources were compared; two had identical configurations to those previously reported, and the other was designed by the authors. The measured Nu's of the lower head were about 30% lower than those previously reported. The measured angular heat flux ratios were similar to those reported in existing studies except for the peaks appearing near the top. The volumetric heat sources did not affect the Nu of the lower head but affected the Nu of the top plate by obstructing the rising flow from the bottom.

• Medical Lasers
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• 제10권2호
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• pp.115-119
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• 2021

A giant thyroid mass can be associated with severe compressive symptoms, requiring surgery for treatment. This paper reports the case of an 82-year-old man who presented with a giant thyroid mass that was suspected of being a metastatic papillary thyroid carcinoma on fine-needle aspiration cytology. A harmonic scalpel was used to excise the giant thyroid mass. A pectoralis major myocutaneous flap was used for reconstruction. The histopathology assessment confirmed the metastases in the lymph node and papillary thyroid carcinoma in the resected gland.

• 대한두경부종양학회지
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• 제29권1호
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• pp.14-17
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• 2013

Giant cell reparative granuloma(GCRG) is a non-neoplastic rapidly expanding and locally destructive tumor that occurs almost exclusively within the mandible and maxilla. A 58-year-old man, complained of a mass on the left infra-auricular area starting 2 months ago. The radiologic finding suggests a mass that originate from mandible, pathology diagnosed the lesion as a giant cell reparative granuloma. The tumor was surgically excised without complications. We report the case with a review of literature.

• 소음진동
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• 제10권5호
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• pp.865-872
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• 2000

This paper presents the modeling, theoretical formulation, and stability analysis for a combined system of a spinning disc and a head that contacts the disc. In the analytic model, head interference is considered by a rotating mass-spring-damper system together with a frictional follower force on the damped annular discs. The multiple scale method is utilized to perform the stability system that shows the existence of instability associated with parametric resonances. Using the formulated system , instability regions of optical recording disc are investigated with variation of mass, stiffness and friction force of a head, respectively. The simulation results show that the stiffness of a head is the most sensitive parameter on the instability of the disc.

• 대한두경부종양학회지
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• 제30권2호
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• pp.79-82
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• 2014

Salivary gland tumors take possession of almost 5% in head and neck malignancies. Among these, mucoepidermoid carcinoma(MEC) is most common malignany in major salivary glands(12-29%) and the parotid gland is most predilection site. Intra-oral MEC has a tendency to various locations, and the predilection sites are palate, cheek, mandible, lip and tongue in order of frequency. A few cases of MEC are occurred in with retromolar trigone, oropharynx, and ectopic salivary gland. Recently, we experienced a-65-year old woman with retromolar trigonal mass, and she was finally diagnosed as MEC. We report it with review of literature.

• 대한두경부종양학회지
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• 제13권1호
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• pp.69-73
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• 1997

We have experienced a case of occult papillary thyroid carcinoma presenting as an anterior mediastinal mass in a 40-year-old man. The CT scan revealed a huge mass behind the manubrium of the sternum but the ultrasound examination failed to detect any lesion and developmental defect in the thyroid. Excision of the mediastinal mass and total thyroidectomy were carried out. Histologically, the mediastinal mass turned out to be papillary carcinoma without any portion of the normal thyroid tissue or normal lymph node tissue and the thyroid gland showed a tiny papillary carcinoma with the diameter of 0.3cm. Although a mediastinal mass as the sole presentation of the thyroid carcinoma is very rare, we suggest that a mediastinal mass should be added to the list of possible metastatic thyroid carcinoma.

• Journal of Astronomy and Space Sciences
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• 제32권4호
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• pp.419-425
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• 2015

In this study, a new idea for developing a space scale for measuring mass in a microgravity environment was proposed by using the inertial force properties of an object to measure its mass. The space scale detected the momentum change of the specimen and reference masses by using a load-cell sensor as the force transducer based on Newton's laws of motion. In addition, the space scale calculated the specimen mass by comparing the inertial forces of the specimen and reference masses in the same acceleration field. By using this concept, a space scale with a capacity of 3 kg based on the law of momentum conservation was implemented and demonstrated under microgravity conditions onboard International Space Station (ISS) with an accuracy of ${\pm}1g$. By the performance analysis on the space scale, it was verified that an instrument with a compact size could be implemented and be quickly measured with a reasonable accuracy under microgravity conditions.

• 대한두경부종양학회지
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• 제31권2호
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• pp.82-85
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• 2015

Adenocarcinoma is a cancer that begins in glandular cells and can occur in several parts of the body. Adenocarcinoma is a rare malignancy of the oropharynx with a few cases reported in the previous report. We describe 1 case of adenocarcinoma of the oropharynx. 46-year-old man was found to have an asymptomatic left tonsil mass and left neck mass that revealed adenocarcinoma by biopsy. A left tonsillectomy and selective neck dissection was performed and pathology confirmed adenocarcinoma with tonsil and neck mass. We report this case with a brief literature review.