• 정보저장시스템학회논문집
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• 제5권2호
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• pp.76-81
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• 2009

Mobile devices have become an important part of daily life. This is especially true of laptop PCs, which are portable enough to be used almost anywhere. Laptop PCs, however, cannot be nomadic if each component is not robust enough to endure rugged laptop operating environment. Generally, external shock makes collision on head-disk interface and damage to read-write performance. To minimize the likelihood of failure, shock analysis must be incorporated into the design of hard disk drive in laptop. This research explores the structure modification of laptop HDD base, for improving shock performance using finite element analysis which considers the flexibility of whole HDD structure. FE model is verified by modal test and finely tuned. Then we obtained the transmitted acceleration of spindle and pivot and the relative displacement between disk and slider head as shock response. Based on shock simulation, the structural dynamics modification is performed and the primary design parameters are extracted.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.65-69
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• 2004

The small form factor optical data storage devices are developing rapidly nowadays. Since it is designed for portable and compatibility with flash memory, its components such as disk, head, focusing actuator, and spindle motor should be assembled within 5 m thickness. The thickness of focusing actuator is within 2 mm and the total working range is $+/-100{\mu}m$, with the resolution of less than $1{\mu}m$. Since the thickness is limited tightly, it is hard to place the yoke that closes the magnetic circuit and hard to make strong flux density without yoke. Therefore, Halbach array is adopted to increase the magnetic flux of one side without yoke. The proposed Halbach array type focusing actuator has the advantage of thin actuation structure with sacrificing less flux density than conventional magnetic array. The optical head unit is moved on the swing arm type tracking actuator. Focusing coil is attached to swing arm, and Halbach magnet array is positioned at the bottom of deck along the tracking line, and focusing actuator exerts force by the Fleming's left hand rule. The working range and resolution of focusing actuator are analyzed with FEM and experiment.

• 임상이비인후과
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• 제29권2호
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• pp.254-258
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• 2018

The solitary fibrous tumor (SFT) is a mesenchymal neoplasm that is described as spindle-shaped tumor cells on a collagenous background originating from pleural tissues. Recently, extrapleural SFT has been reported in nearly all sites, including the sublingual gland, parotid gland, nasal cavity and paranasal sinuses. Complete surgical excision is primary treatment for SFT, but diagnosing SFT is not often made until immunohistochemical evaluation after surgical resection. We report that the patient, 45-year-old male, was considered as a case of inflammation polyp arising from left nasal cavity with initial biopsy, however, it has turned out to be SFT after surgical treatment.

• 대한두경부종양학회지
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• 제39권2호
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• pp.7-11
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• 2023

Adult fibrosarcoma is a malignant tumor comprising of spindle-shaped fibroblasts with variable collagen production. Due to their aggressive nature and high probability of local tumor recurrence, these tumors require accurate diagnosis and resection according to guidelines. A 57-year-old male presented to the clinic with a complaint of a palpable growing mass in the left scapular area. Examination of the back revealed a 6 cm protruding tumor with a nodular surface. We performed a wide excision, including the infraspinatus fascia layer and subsequent reconstruction using a parascapular island flap. Histopathological analysis demonstrated the typical microscopic features of adult fibrosarcoma. At the 3-year follow-up, there was no evidence of local recurrence and the resection margin was completely clear of tumor.

• Journal of Korean Neurosurgical Society
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• 제37권3호
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• pp.238-240
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• 2005

Meningioma is usually known to occur stuck to the dura mater, but extradural meningioma occurs rarely. Most of the extradural meningiomas are located in the head and neck and we report a case of the primary intraosseous meningioma in the orbit. A 50-year old woman presented with the left eye hyperemia and exophthalmos. Neuroimaging modalities showed hyperostosis at the left sphenoid and orbital wall. On microscopic view, spindle cells and psammoma bodies between the woven bones were observed. The origin of the intraosseous meningioma is explained with various potent possibilities and differential diagnosis thoroughly explored.

• Archives of Plastic Surgery
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• 제32권1호
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• pp.139-142
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• 2005

Atypical fibroxanthoma(AFX) is a tumor that occurs as a solitary and ulcerative nodule on actinically damaged or radiation damaged skin of the head and neck in the elderly. AFX is a pleomorphic spindle cell neoplasm of the dermis, which is a clinically benign reactive lesion despite of apparently malignant histologic features. We report a case of AFX which developed on the nasal root area of a 23-year-old man. This case is very unusual in terms of site(less sun-damaged area), overlying skin feature(grossly normal skin) and age(too young). This tumor was completely removed with surgical excision and remained free of recurrence for a period of about 1 year follow-up.

• Archives of Plastic Surgery
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• 제32권6호
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• pp.770-772
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• 2005

Nodular fasciitis is an unusual benign tumor which is composed of myofibroblast. Typical histologic findings include haphazardly arranged pleomorphic arranged spindle cells in a myxoid stroma. These lesions may easily be misinterpreted as malignancy clinically and histologically because it presents as a rapidly growing mass from subcutaneous or deep fascia. These lesions are usually located over upper extremity and rarely in the head and neck region. It's important to emphasize the need of clinical suspicion and accurate histopathology of this rare benign lesion usually misdiagnosed as a malignacy to avoid unnecessary and inappropriate aggressive wide resection, when encountering subcutaneous nodules of the face and neck region. In this article, we report a rare case of Nodular fasciitis on the Nose and some reviews of the literature.

• Archives of Plastic Surgery
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• 제33권3호
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• pp.383-387
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• 2006

Atypical fibroxanthoma is a pleomorphic spindle cell neoplasm characterized by a variable combination of cells with fibroblastic and histiocytic features. It occurs mostly on sun-exposed area of the head and neck of elderly person and is a clinically benign reactive lesion despite apparent malignant histologic features. However, because of its potential for metastasis, it is widely regarded as a low-grade sarcoma. We report a 30-year-old woman with atypical fibroxanthoma developed on the left occipital area. The lesion was $1.5{\times}2cm$ sized papule. There was no skin lesion such as ulcer or eschar. However, mass was involving occipital bone and composed of dense, pleomorphic spindle cells and several bizarre multinucleated giant cells. After wide excision of the scalp and occipital bone, the defect was covered with bone cement, bipedicled local flap and the donor site was covered with STSG. The wound healed completely without complication. It remained free of recurrence for a period of about 1 year follow up.

• 대한두경부종양학회지
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• 제14권2호
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• pp.220-227
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• 1998

The clinical and pathological features of 35 cases of anaplastic thyroid cancer were studied. These tumors occurred in 12 men and 23 women ranging in age from 19 to 83 years(mean age; 61.7 years). A rapidly enlarging thyroid mass was the most common presentation. The duration of the presence of mass varied from 20 days to 12 months with an average of 2.7 months. Systemic metastasis at the time of initial examination was found in 14 patients(40.0%) and the lung was the most common site of involvement. The overall rate of distant metastasis was about 65.7%. The tumors were subdivided morphologically into giant cell type of 10 cases, spindle cell type of 7 cases, epidermoid cell type of 1 cases, and mixed giant cell and spindle cell type of 5 cases. The mean survival period of 6 among 35 patients who had biopsy alone was 1.4 months. The 22 patients underwent the incomplete combined treatment modalities (palliative surgery with or without chemotherpy or radiation therapy) survived for a mean period of 3.0 months, among them, 7 patients who had surgery combined with chemotherapy and radiation therapy showed mean survival period of 3.7 months. The mean survival of 7 patients who had complete combined treatment modality(curative surgery combined with chemotherapy and hyperfractionated radiation therapy) was 6.6 months, only one patient survived for 21 months and one patient has been alive for 1 month after operation, and the others survived for a mean period of 4.8 months. So far, as of July 31, 1998, 34 patients among 35 were died(one has been survived for 1 month) despite the various treatment modalities, and the main cause of death were failure of local control and systemic metastasis. None of the various treatment modalities gave consistently favourable results. However, a combination of surgery, radiation therapy and chemotherapy seemed to have a slight positive effect on survival. Furthermore, the aggressive treatment modalities will be indicated only in the early diagnosed and minimal cases.

• Tribology and Lubricants
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• 제22권2호
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• pp.59-65
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• 2006

In hard disk drives as the head to disk spacing continues to decrease to facilitate recording densities, slider disk interactions have become much more severe due to direct contact of head and disk surfaces in both start/stop and flying cases. The slider disk interaction in CSS (contact-start-stop) mode is an important source of particle generation and tribocharge build-up. The tribocharge build-up in the slider disk interface can cause ESD (electrostatic discharge) damage. In turn, ESD can cause severe melting damage to MR or GMR heads. The spindle speed of typical hard disk drives has increased in recent years from 5400 rpm to 15000 rpm and even higher speeds are anticipated in the near future. And the increasing disk velocity leads to increasing disk acceleration and this might affect the tribocharging phenomena of the slider/disk interface. We investigated the tribocurrent/voltage build-up generated in HDD, operating at increasing disk accelerations. In addition, we examined the effects with relative humidity conditions and rest time. We found that the tribocurrent/voltage was generated during pico-slider/disk interaction and its level was about $3\sim16pA$ and $0.1\sim0.3V$, respectively. Tribocurrent/voltage build-up was reduced with increasing disk acceleration. Higher humidity conditions $(75\sim80%)$ produced lower levels tribovoltage/current. Therefore, a higher tribocharge is expected at a lower disk acceleration and lower relative humidity condition. Rest time affected the charge build-up at the slider-disk interface. The degree of tribocharge build-up increased with increasing rest time.