• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.4
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• pp.140-144
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• 2015

Effects of the shape, the size and the material of head mass on performances of tonpilz transducer were studied with a finite element method. The shape of head mass was changed with an angle between symmetric axis and side of head mass of transducer from 0 to 60 degree. As a result of the simulations, the bandwidth leached to 86.4 % at 35.5 degree in case of Al head mass. The size of head mass showed a decrease in the power of transducer with little change of bandwidth. For the Ti head mass, the transmitted power showed 100 % increase with a bandwidth of 88.1 % even though the weight of the head mass increased to 167 % of Al. This can be attributed to the mechanical properties like elastic modulus of Ti relative to Al.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.3
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• pp.330-336
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• 2009

This paper studies on the new control algorithm for the mass-flow stabilization in strip head part of a hot strip mill. A new strip tension model in the strip head part is derived using the current deviation of two neighboring stands. The current deviation means a difference between a measured current and a lock-on current, where the lock-on current is set up when a strip tension or a looper angle reaches each target value or time is about 0.4sec, respectively. On the basis of the tension calculation model, a mill velocity of a backward stand is controlled to stabilize a strip mass-flow by PI control algorithm. Therefore, the mass-flow control for strip head part is executed from a metal-in time into a foreward stand till the looper works normally. It is known by the results of a computer simulation and an experiment that the proposed control algorithm is very effective in stabilizing the mass flow of the strip head part.

• The Journal of the Acoustical Society of Korea
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• v.29 no.7
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• pp.422-430
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• 2010

The radiation property of a Tonpilz transducer is influenced by the structural variables of the transducer. In this study, with respect to a single mode Tonpilz transducer, the radiation patterns were calculated for different head mass geometries of the same effective radiation area. The shapes of the head mass analyzed were the most popular circular, regular triangular, square, regular hexagonal and regular octagonal types, and radiation pattern equations were derived for each of the head mass shapes. Based on the derived equations, radiation patterns in accordance with the shape and size of the head mass were calculated and the results were compared with each other. Validity of the calculation results were confirmed by means of finite element analysis.

• Journal of Clinical Otolaryngology Head and Neck Surgery
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• v.29 no.2
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• pp.301-306
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• 2018

Immunoglobulin G4-related disease (IgG4RD) is a chronic inflammatory condition characterized by tissue infiltration with lymphocytes and IgG4-secreting plasma cells, as well as varying degrees of fibrosis. We report a case of a 70-year-old man with a rapid-growing cervical mass for several months. Computed tomography and positron emission tomography showed a huge, ill-defined mass involving left thyroid lobe and encasing the common carotid artery, which was clinically and radiologically suspicious for anaplastic thyroid carcinoma. Ultrasonography-guided core needle biopsy was performed and histopathology examination revealed to be consistent with IgG4RD, and the IgG4/IgG ratio was 0.6. After oral corticosteroid was administered, the mass was dramatically resolved. Because IgG4RD often presents as a single localized and infiltrated mass lesion, it can be confused and misdiagnosed as a malignancy. Thus, clinicians should consider IgG4RD as a differential diagnosis in a rapid-growing neck mass to prevent unnecessary and excessive treatments.

• Korean Journal of Head & Neck Oncology
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• v.10 no.2
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• pp.157-162
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• 1994

It is the purpose of this paper to determine the relative frequency of the neoplastic vs. non-neoplastic disease in a series of surgically removed parotid and submandibular masses. The study was conducted a retrospective review of 249 consecutive, operated patients' records seen over a 9-year period from 1985 through 1993 at Department of Otolaryngology-Head and Neck Surgery, Korea Cancer Center Hospital. One hundred and fifteen patients had parotid mass and 134 patients had submandibular mass. All the specimen surgically removed were studied histopathologically. The numbers and percentages of patients are reported along with a pathological classification of the lesions encountered: neoplastic(benign, malignant) and non-neoplastic (inflammatory, non-inflammatory). There were 59 benign, 46 malignant, 6 inflammatory, 4 non-inflammatory in 115 parotid mass, and 33 benign, 48 malgnant, 47 inflammatory, 6 non-inflammatory in 134 submandibular mass. One-hundred-eighty-six of entire 249 patients had tumor involvement, for a 74.7% incidence of neoplasia. There was a neoplastic predominance in parotid mass(91.3%) and a relative inflammatory predominance in submandibular mass(35.1%).

• Korean Journal of Head & Neck Oncology
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• v.29 no.2
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• pp.71-74
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• 2013

Neck mass is a common manifestation from head and neck malignancy, most of which come from mucosal squamous cell carcinomas in the upper aero-digestive tract. However, once aspiration cytology suggests atypical malignant cells in the neck mass rather than metastatic squamous cell carcinomas, it is confusing to decide the adequate diagnostic work-ups and treatment planning. Here, we report a 29-year-old woman presenting with a growing neck mass mimicking malignancy of unknown origin, which was finally diagnosed as primary lymphoepithelial carcinoma in the parotid gland with multiple metastases to the lymph nodes. The patient underwent comprehensive neck dissection and total parotidectomy and the adjuvant radiation treatment was given. Our report highlight that the primary salivary gland cancer should be considered as the potential tumor origin in case of malignancy of unknown origin in the head and neck region and neck mass suggestive of atypical carcinomas.

• Korean Journal of Head & Neck Oncology
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• v.26 no.2
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• pp.250-252
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• 2010

Vascular leiomyomas are benign tumors of smooth muscle origin arising from the muscularis layer of blood vessel walls. They can occur anywhere in the body where smooth muscle is found and usually occur in the lower extremity as a slow-growing, firm, occasionally painful mass. However they are rare in the head and neck and very rare in hard palate. Here we report a case of a vascular leiomyoma presenting as a soft mass of the hard palate and review the literatures.

• Korean Journal of Head & Neck Oncology
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• v.26 no.2
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• pp.221-224
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• 2010

Papillary thyroid carcinoma frequently invades the lymph node, trachea, esophagus and perithyroid tissue. However, direct extension to posterior pharyngeal area is known to be rare. A 64-year-old male was referred to our clinic presenting as posterior pharyngeal mass during gastrofiberscopy. The neck CT scan showed soft tissue mass in retropharynx and lymph node in right level III with calcifications. We performed the total thyroidectomy with selective(level II, III, IV) and anterior compartment neck dissection. In operative findings, the right thyroid mass were connected to the retropharynx through the posterior portion of inferior constrictor muscle. Histopathologic findings revealed the papillary thyroid carcinoma extended to retropharynx. We report a unique case with a literature review.

• Korean Journal of Bronchoesophagology
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• v.13 no.2
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• pp.72-77
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• 2007

The case report of migrating ingested fish bone presenting as an unresolving inflamed neck mass is rare. The diagnosis must be suspected in a patient with an unresolving inflamed cutaneous lesion, especially one with a punctum, the tenderness of the lesion elicited on swallowing and the presence of a palpable subcutaneous neck mass. In such a patient, a history of recent foreign body ingestion must be actively sought. An accurate early diagnosis of this easily treatable condition is desirable because it could avert unnecessary delays, inconveniences, anxiety, costs, and surgery. The authors experienced a case of lateral neck mass resulting from the migration of a fish bone which was successfully removed by surgical exploration and made a report with a review of literature.

• Korean Journal of Head & Neck Oncology
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• v.23 no.2
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• pp.178-180
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• 2007

Tortuosity of the internal carotid artery is not a rare condition. A 68-year-old woman presented with a 3 years' history of a pulsatile tinnitus and throat abnormal sensation. On physical examination, a soft pulsatile mass on the left posterior oropharyngeal wall was noted. By neck CT and neck MRI the tortuous internal carotd artery was visualized. Otolaryngologists should recognize this anomaly and the patient should be made aware of their condition, because it may cause a fatal or near-fatal hemorrhage during surgical procedures in the pharynx, especially tonsillectomy and adenoidectomy and drainage of peritonsillar abscess. We report a case of a left internal carotid artery tortuosity as an oropharyngeal mass.