• 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.

• Investigative Magnetic Resonance Imaging
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• v.21 no.3
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• pp.177-182
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• 2017

Schwannomas are benign nerve sheath tumors that are typically located in soft tissue. Occasionally, schwannomas involve osseous structures. These intraosseous schwannomas are generally benign neoplasms that account for less than 0.2% of primary bone tumors. Schwannomas are very rarely observed in long bones. We present a case of a schwannoma affecting the proximal femur with a coincident subchondral fracture of the femoral head. A 38-year-old-male presented with left hip pain without deteriorating locomotor function. Plain film radiographs displayed a lobulating contoured lesion within the intertrochanteric portion of the femur. The magnetic resonance imaging (MRI) scans showed a tumor occupying the intertrochanteric region. Diffuse bone marrow edema, especially in the subchondral and head portions of the femur that was possibly due to the subchondral insufficiency fracture was also noted. The lesion was surgically excised and bone grafting was performed. Histologically, there was diffuse infiltrative growth of the elongated, wavy, and tapered cells with collagen fibers, which are findings that are characteristic of intraosseous schwannoma. Although very rare, intraosseous schwannoma should be included in the differential diagnosis of radiographically benign-appearing, non-aggressive lesions arising in the femur. The concomitant subchondral fracture of the femoral head confounded the correct diagnosis of intraosseous schwannoma in this case.

• Tuberculosis and Respiratory Diseases
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• v.62 no.3
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• pp.227-231
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• 2007

Several types of infection can cause organizing pneumonia when the inflammatory process remains active with the further organization of the intra-alveolar fibrinous exudates, despite the control of the infectious organism by antibiotics. We report a case of 37-year-old male with secondary organizing pneumonia associated with an endobronchial actinomycosis. The patient presented with a subacute cough, sputum and fever. Bronchial biopsy revealed sulfur granule to be consistent with the actinomycosis, and percutaneous needle biopsy revealed typical pattern of organizing pneumonia. The patient was treated with the appropriate antibiotics and corticosteroid. There was rapid improvement in the symptoms and radiological findings, and after six months of treatment, the corticosteroid dose was tapered off without a recurrence of the organizing pneumonia.

• Tuberculosis and Respiratory Diseases
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• v.67 no.4
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• pp.359-363
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• 2009

Immunoglobulin G4 (IgG4) related autoimmune diseases are characterized by high serum IgG4 concentrations, sclerosing inflammation of numerous IgG4-positive lymphoplasma cells of varying origin, and a positive response to steroid treatment. Autoimmune pancreatitis, sclerosing cholangitis, and retroperitoneal fibrosis are representative presentations of IgG4 related autoimmune disease. Herein, we describe 2 patients (40-years-old woman and 47-years-old man) diagnosed with pulmonary involvement of IgG4-related autoimmune disease. The patients were admitted for an evaluation of the lung mass or multiple lung nodules found on chest radiography. Surgical lung biopsies were performed and pathologic finding revealed lymphoplasmacytic sclerosing inflammation with numerous IgG4 positive cells. The patients had elevated serum total IgG and IgG4 levels. Treatment consisted of high dose methylpredinisolone (1 mg/kg/day) and demonstrated good responsiveness. However, one patient experienced 2 relapses while being tapered off of steroid treatment.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.3
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• pp.379-392
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• 2005

Statement of problem. One of the common problems of dental implant prosthesis is the loosening of the screw that connects each component, and this problem is more common in single implant-supported prostheses with external connection, and in molars. Purpose. The purposes of this study were: (1) to compare the initial abutment screw detorque values of the six different implant-abutment interface designs, (2) to compare the detorque values of the six different implant-abutment interface designs after cyclic loading, (3) to compare the detorque values of regular and wide diameter implants and (4) to compare the initial detorque values with the detorque values after cyclic loading. Material and methods. Six different implant-abutment connection systems were used. The cement retained abutment and titanium screw of each system were assembled and tightened to 32Ncm with digital torque gauge. After 10 minutes, initial detorque values were measured. The custom titanium crown were cemented temporarily and a cyclic sine curve load(20 to 320N, 14Hz) was applied. The detorque values were measured after cyclic loading of one million times by loading machine. One-way ANOVA test, scheffe’s test and Mann-Whitney U test were used. Results. The results were as follows : 1. The initial detorque values of six different implant-abutment connections were not significantly different(p>0.05). 2. The detorque values after one million dynamic cyclic loading were significantly different (p<0.05). 3. The SS-II regular and wide implant both recorded the higher detorque values than other groups after cyclic loading(p<0.05). 4. Of the wide implants, the initial detorque values of Avana Self Tapping Implant, MIS and Tapered Screw Vent, and the detorque values of MIS implant after cyclic loading were higher than their regular counterparts(p<0.05). 5. After cyclic loading, SS-II regular and wide implants showed higher detorque values than before(p<0.05).

• Korean Journal of Optics and Photonics
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• v.10 no.1
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• pp.73-79
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• 1999

Semiconductor optical switch modules of 1$\times$2, 1$\times$4, and 4$\times$4 types for 1550 nm optical communication systems were fabricated by using laser welding technique, embodying in 30-pin butterfly package. For better coupling efficiency between switch chip and optical fiber, tapered fibers of 10~15mm lens radii were used, which provided up to 60% optical coupling efficiency. With the help of new laser hammering process, we could recover the lost optical power almost completely up to average 82% of initially obtained power. The fabricated optical switch modules showed good thermal stability of less than 5% degradation even after 200 times thermal cycling test. The 2.5 Gbps optical transmission characteristics of the 4$\times$4 switch module showed low sensitivities of less than -30dB for all possible switching paths. The transmission penalties of 1$\times$2 switch module at $10^{-10}$ BER were 0.6dB and 0.7dB for 50Xm and 90 Km optical fibers, respectively.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.3
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• pp.301-312
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• 1999

The purpose of this study was to compare the accuracy of currently used elastomeric impression materials for complete arch impression taking. Five elastomers (Impregum, Permlastic, Express, Extrude, Examix) and one Irreversible hydrocolloid (Aroma-fine) were tested. For each material, 5 impressions were made of stainless steel model to which five tapered posts were attached. Custom trays were used for polyether and polysulfide impression materials, and putty/wash two step technique was used for addition polyvinylsiloxane impression materials. Improved stone mod els were poured to all impressions. Accuracy of the materials was assessed by measuring ten distances on stone dies poured from impressions of the master model. All measurements for master and improved stone models were made with three dimensional measuring machine. The results were as follows 1. The dimensional accuracy of polyether, extrude, and examix were significantly superior to poly-sulfide, exress, and alginate in reproducing full arch mode (p<0.05) 2. There were no statistical differences in dimensional accuracy for full arch impression between polyether extrude and examix (p>0.05). 3. there were no statistical differences in dimensional accuracy between polysulfide, express, and alginate(p>0.05). 4. There were no statistical differences between addition polyvinyl siloxane materials (p>0.05) 5. There were no statistical differences between anterior-posterior and lateral dimensional changes of all impression materials (p>0.05).

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.3
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• pp.539-549
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• 1995

The purpose of this study was to determine the accuracy of 3 implant impression methods by using strain gauge. The models used for this study were partially edentulous mandibular acrylic resin casts Model A, with two abutment analogs in #46,47 extraction site, represented two implant parallel to to the adjacent natural tooth. Model B represent an anterior implant parallel to the adjacene natural tooth and a posterior implant exhibiting a 15-degree lingual inclination. Master framework were fabricated on the master model, and 3 strain gauges were attached to a master framwork to determine the passivity of fit of the framework to sample casts made by the three impression techniques. The master framework was attached to each sample cast with gold screws, which were tightened with the torque driver to ensure a consistent toque application of 10 Ncm. Universal Digital Measuring System UCAM-5BT was used for strain measuring. Impression techniques studid were : 1. unsplinted tapered impression coping, polyvinyl siloxane, stock tray 2. unsplinted squared impression coping, polyether, custom tray 3. squared impression coping splinted with Duralay resin, polyether, custom tray Through analysis on data from this study, the following conclusions were obtained. 1. There were no statistically significant differences between the mean strain recorded from the sample casts made with the tree impression. But only strain values of model A(parallel group) Y-axis was signifcantly differed between Technique 1 and 3(P<0.05). 2. There was no statistically significant difference between model A(parallel group) and model B(15-degree divergent group).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.7
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• pp.608-616
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• 2009

This paper presents a broadband CPS-fed Yagi-Uda antenna. The antenna has a feedline structure much simpler than other Yagi-Uda antennas and it provides more design flexibility in arranging the reflector. To improve the impedance matching, a tapered CPS line is inserted between the thick and thin feedlines. The proposed antenna exhibits the bandwidth of $3.9{\sim}5.9$ GHz (|G| < -10 dB) and the gain of $6.5{\sim}8$ dBi within that bandwidth. At the center frequency of 4.9 GHz, the antenna shows the gain of 7.4 dBi, and HPBW of $98^{\circ}$ along the x-z plane and $73^{\circ}$ along the x-y plane.

• Journal of the Korean Geotechnical Society
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• v.35 no.11
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• pp.63-74
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• 2019

Numerical liquefaction model and response history analysis procedure are verified based on dynamic centrifuge test results. The test was a part of the Liquefaction Experiments Analysis Project (LEAP). The model ground was formed inside of rigid box by using the submerged Ottawa F65 sand with a relative density of 55% and 5° of surface inclination. A tapered sinusoidal wave with a frequency of 1 Hz was applied to the base of the model box. Numerical analyses were performed by two dimensional finite difference method in prototype scale. The soil is modeled to show hysteretic behavior before shear failure, and Mohr-Coulomb model is applied for shear failure criterion. Byrne's liquefaction model was applied to track the changes in pore pressure due to cyclic loading after static equilibrium. In order to find an appropriate flow condition for the liquefaction analysis, numerical analyses were performed both in drained and undrained condition. The numerical analyses performed under the undrained condition showed good agreement with the centrifuge test results.