• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.2
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• pp.69-75
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• 2004

In this paper, we propose the shape of extremely small thrust VCM for application of the Nanoindenter, which enables control of very small force and displacement. We performed optimization of the VCM shape using conjugated gradient method. And the purposes of optimization are the minimization of the permanent magnet size for the efficient systems, minimization of deviation of flux density from the air gap for operate on regular thrust and a linearization of thrust for a good control characteristic. The finite element method is used for characteristic analysis. The node moving method is used to redundant changes of design variables. As a result, the VCM produces a yew small force by the difference of flux density of lower part from higher one. Also, in a wide range of current (0［A］-1［A］), the VCM produces linear driving thrust by saturating the magnetic circuit path and operate on regular thrust by minimizing deviation of flux density of the air gap.

• Transactions on Electrical and Electronic Materials
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• v.12 no.1
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• pp.16-19
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• 2011

The oxide-nitride-oxide (ONO) deposition process was added to the beginning of a 0.25 ${\mu}m$ embedded polysiliconoxide-nitride-oxide-silicon (SONOS) process before all of the logic well implantation processes in order to maintain the characteristics of basic CMOS(complementary metal-oxide semiconductor) logic technology. The system subsequently suffered severe ONO rupture failure. The damage was caused by the ONO implantation and was responsible for the ONO rupture failure in the embedded SONOS process. Furthermore, based on the experimental results as well as an implanted ion's energy loss model, processes primarily producing permanent displacement damages responsible for the ONO rupture failure were investigated for the embedded SONOS process.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1530-1531
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• 2007

본 논문은 미러 표면에 형성된 코일과 미러 양쪽에 위치한 영구자석간의 전자기력에 의해 구동되는 마이크로미러의 설계 및 결과를 나타낸다. $4mm\;{\times}\;4mm$ 크기를 갖는 미러의 전자기 특성 및 구동을 유한요소해석 프로그램인 COMSOL Multiphysics를 이용하여 시뮬레이션 하였다. 4 kHz의 공진주파수 특성을 갖도록 설계된 마이크로미러는 코일에 $3.6\;A/mm^2$의 current density 적용 시 x-, y-axis displacement가 각각 $1.2{\mu}m$, $12{\mu}m$가 되는 것으로 나타났다.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.7 no.1
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• pp.33-37
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• 2011

The ectopic eruption is defined as abnormal eruption which gives to displacement of the teeth and abnormal root resorption of adjacent teeth. The prevalence of ectopic eruption is reported to vary 2~6%, most of them are in the maxilla. Etiologic factors include narrow maxilla, large maxillary teeth, inclined eruption path of the first molar, retruded position of the maxilla and hereditary factor. Irreversible ectopic eruption where the second primary molar is lost often causes mesial tipping and rotation of the permanent molar, unfavorable occlusion and space deficiency for the second premolar. Ectopically erupted teeth should be treated early to maintain normal development of the dentition, harmony of facial growth and occlusal support. The method of the treatment are classified as follows : appliances that is positioned at the contact point for unlocking and the distal movement, fixed appliance that is connected to more than one tooth, and occlusion guiding method after disking or extraction of the second deciduous molar. A case report of a patient with bilaterally ectopic eruption of maxilla and mandible first permanent molar was present. Also, the patient who had experienced the chronic myelogenous leukemia, show various dental developmental complications. The ectopic eruption was treated with a Halterman appliance that was a effective way of correcting of ectopic eruption of the permanent first molar.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.1
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• pp.75-81
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• 2011

Supernumerary teeth are in excess of the normal number of teeth in either the primary or permanent dentitions. They are classified into supplemental teeth resembling those of the normal series and rudimentary teeth with abnormal shapes, according to their form. Most of the supernumerary teeth are rudimentary form, and supplemental teeth are much less common. Sulppemental teeth are most common in the permanent maxillary lateral incisor area and clinicians should be careful with differential diagnosis from normal teeth. Unerupted supernumerary teeth may produce several complications such as delayed eruption, displacement of permanent teeth, diastema, root resorption and cyst formation. Early detection and proper treatment plan according to the tooth alignment and root formation stage are important. Here we report 3 cases of unilateral or bilateral normal incisor shaped supernumerary lateral incisors treated by eruption observation, surgical extraction and orthodontic treatment with resin build-up.

• JSTS:Journal of Semiconductor Technology and Science
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• v.1 no.1
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• pp.84-93
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• 2001

An electromagnetic micro x-y stage for probe-based data storage (PDS) has been fabricated. The x-y stage consists of a silicon body inside which planar copper coils are embedded, a glass substrate bonded to the silicon body, and eight permanent magnets. The dimensions of flexures and copper coils were determined to yield $100{\;}\mu\textrm{m}$ in x and y directions under 50 mA of supplied current and to have 440 Hz of natural frequency. For the application to PDS devices, electromagnetic stage should have flat top surface for the prevention of its interference with multi-probe array, and have coils with low resistance for low power consumption. In order to satisfy these design criteria, conducting planar copper coils have been electroplated within silicon trenches which have high aspect ratio ($5{\;}\mu\textrm{m}$in width and $30{\;}\mu\textrm{m}$in depth). Silicon flexures with a height of $250{\;}\mu\textrm{m}$ were fabricated by using inductively coupled plasma reactive ion etching (ICP-RIE). The characteristics of a fabricated electromagnetic stage were measured by using laser doppler vibrometer (LDV) and dynamic signal analyzer (DSA). The DC gain was $0.16{\;}\mu\textrm{m}/mA$ and the maximum displacement was $42{\;}\mu\textrm{m}$ at a current of 180 mA. The measured natural frequency of the lowest mode was 325 Hz. Compared with the designed values, the lower natural frequency and DC gain of the fabricated device are due to the reverse-tapered ICP-RIE process and the incomplete assembly of the upper-sided permanent magnets for LDV measurements.

• Archives of Craniofacial Surgery
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• v.14 no.2
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• pp.133-136
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• 2013

Retrobulbar hemorrhage is a rare but serious complication after blepharoplasty, mid-face injury, and treatment of facial bone fractures. The incidence of postoperative retrobulbar hemorrhage is 0.055% with an incidence of associated permanent blindness of 0.005%. A 69-year-old male came to the emergency room with pain on both orbital areas and uncontrolled bleeding after cosmetic lower blepharoplasty performed at a private clinic. He had not been evaluated preoperatively by the private clinic, but we found that he had undergone percutaneous transluminal coronary angioplasty and taken anticoagulants for 10 years. We performed an emergency operation to evacuate the hematoma. However, after surgery, he persistently complained of orbital pain, pressure and diminished visual acuity. Intraocular pressure was increased, and computed tomography demonstrated a retrobulbar hemorrhage with globe displacement. Emergent lateral canthotomy and cantholysis were performed. Intraocular pressure was decreased to 48/30 mm Hg immediately after the operation, falling within the normal range the next day. We recommend three points to minimize loss of vision by retrobulbar hematoma. Firstly, careful preoperative evaluation must be conducted including current medications, underlying diseases and previous history of surgeries. Secondly, cautious postoperative observation is important for the early diagnosis of retrobulbar hematoma. Lastly, immediate treatment is crucial to prevent permanent blindness.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.1
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• pp.99-107
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• 2017

In the management of ankylosed primary molars, early diagnosis, proper treatment, and thorough follow-ups are very important. Untreated infraocclusion due to ankylosis has a negative impact on normal occlusal development, and may cause problems. There are many treatment options on infraoccluded deciduous molars, such as periodic observation, conservative method, restoration, and space regaining via extraction of the teeth. In this case report, two 6-year-old girls were diagnosed with ankylosed maxillary second primary molar and displaced tooth germ of the second premolar. Early surgical removal of the ankylosed primary molar was considered as a treatment approach. The long-term follow-up shows normal eruption of a succeeded permanent premolar.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.2
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• pp.219-227
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• 2020

Tooth eruption involves a complex developmental process of tooth migration from the dental follicular origin to the final occlusion position in the oral cavity via the alveolar process. Disturbance of tooth eruption can occur at any point in a series of eruption stages; however, horizontal impaction of the mandibular first molar and primary retention of the primary mandibular second molar are rarely observed simultaneously. This study describes the treatment for two cases of horizontally impacted first molar with primary retention of primary molar. The primary retention of the primary mandibular second molar was extracted, and orthodontic traction was applied to the horizontally impacted primary mandibular first molar. Subsequently, displacement of the premolar tooth bud was improved and space regaining for eruption was achieved, guiding to normal eruption of the first molar.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.1
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• pp.82-87
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• 2011

The pulp infection of primary tooth is often caused by dental caries or trauma. But, if it is not managed properly, it can be produce the periapical lesion. The periapical lesion can cause some complications such as enamel hypoplasia, displacement, root dilaceration and impaction. Treatment options of displaced permanent successor are clinical and radiological follow-up after extraction of primary teeth, surgical opening, orthodontic traction, transplantation and extraction. In these cases, the premolars with abnormal eruption path caused by periapical lesion of the primary tooth have shown successful spontaneous eruption just as a result of extraction of infected primary tooth and space maintenance.