• Tribology and Lubricants
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• v.4 no.1
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• pp.36-42
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• 1988

On the basis of the thermally-activated Wear theory, it is well estabilished that the secondary activated energy, which is mainly resulted from the exothermic reaction of hydrogen from thermal decomposition of the hydrocarbons at the high temperature and the high speed, caused catastropic failure. The new additive, viz., DEP was synthesized to reduce or eliminate the hydrogen effect at the contact junction. Through the thermal degrading and the thermodynamic consideration, the synthesized additive, viz., DEP showed the possibiliy as the hydrogen scavenger.

• Annals of Clinical Neurophysiology
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• v.3 no.2
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• pp.115-121
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• 2001

The occurrence of muscle weakness in patients with sepsis or multiple organ failure managed in the intensive care unit has been recognized with increasing frequency in the last two decades. The difficulty in examining critically ill patients may explain why this complication has been only recently recognized. This weakness is due to an axonal polyneuropathy which is called critical illness polyneuropathy(CIP). It must be differentiated from myopathy or neuromuscular junction disturbance that can also occur in the intensive care setting. Neither the cause nor the exact mechanism of CIP has been elucidated. Electrophysiological studies demonstrated an acute axonal damage of the peripheral nerves. Before the recognition of CIP, these cases were usually misdiagnosed as Guillain-$Barr{\acute{e}}$ syndrome. Clinical recovery from the neuropathy is rapid and nearly complete in those patients who survive. Thus, neuropathy acquired during critical illness, although causing a delayed in weaning from ventilatory support and hospital discharge, does not worsen long-term prognosis.

• Journal of Korean Dental Science
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• v.4 no.1
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• pp.1-5
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• 2011

Purpose: Exact knowledge of the location and dimension of the pulp chamber help to maintain the pulp healthy during operative procedure and also reduces the risk of perforation of pulp chamber during root canal treatment. This in-vivo study was carried out to measure critical morphology of pulp chamber of mandibular molar using intra-oral periapical radiograph. Materials and Methods: Mandibular molar teeth of 56 patients were evaluated. The mandibular molar teeth whose pulp chamber was not violated by caries, restoration, fracture crown and those having closed apex were included in the study. The intraoral periapical radiographs were taken with paralleling angle technique using radio-opaque grid with 1 mm space. This grid was placed directly on the film. Results: In 94% of the mandibular first molars specimens the pulp chamber ceiling was at the level of the cemento-enamel junction. The measurements showing the lowest percentage variance were buccal cusp to furcation (approximately 11%) and buccal cusp to pulp chamber ceiling (approximately 15%). The distance from the cusp tip to pulp chamber ceiling height was approximately 6.0 mm, the distance from the pulpal floor to the furcation was approximately 3.0 mm, and the average height of a pulp chamber was 1.5 to 2.0 mm. Conclusion: The exact knowledge of distances of pulp chamber from various anatomical landmarks helps in proper assessment of root canals and ultimately avoids the failure of root canal treatment.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.2
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• pp.232-242
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• 2003

Statement of problem : Fiber-reinforced posts have lower modulus of elasticity than titanium post or cast post-core. With this similar elasticity to that of dentin, fiber-reinforced posts have been known to have a tendency to reduce the risk of root fracture. However, there were few studies on the teeth restored with fiber-reinforced posts under the condition of reduced periodontal support. Purpose : The purpose of this study was to evaluate the fracture strength and failure mode of endodontically treated teeth restored with fiber-reinforced posts and titanium posts under the condition of reduced periodontal support. Material and method : Extracted human maxillary incisor roots were divided into 3 groups (group 1 carbon fiber post, group 2 : glass fiber post, and group 3 : titanium alloy post). After coronectomy and endodontic treatment, teeth were restored with each post systems and resin core according to the manufacturer's recommendation. Then, teeth with simulated periodontal ligament were embedded in the acrylic resin blocks at the level of 4 mm below the cemento-enamel junction. Each specimen was exposed to $10^5$ load cycles with average 30 N force in $36.5^{\circ}C$ water using a computer-controlled chewing simulator. Loads were applied at $45^{\circ}$ angle to the long axis of the teeth. After cyclic loading, teeth were subjected a compressive load until failure at a crosshead speed of 0.5 mm/min. Fracture strength (N) and failure mode were examined. The fracture strength was analyzed with one-way ANOVA and the Scheffe adjustment at the 95% significance level. Results and conclusion : The results were as follows. 1. There was no statistically significant difference in the mean fracture strength among the groups (P<.05). 2. Carbon fiber post and glass fiber post group showed less root fracture tendency than control group. 3. All specimens with root fractures showed fracture lines above the level of acrylic resin block, except for only one specimen in group 3.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.306-316
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• 2016

In this paper, an NMOS-diode eFuse OTP (One-Time Programmable) memory cell is proposed using a parasitic junction diode formed between a PW (P-Well), a body of an isolated NMOS (N-channel MOSFET) transistor with the small channel width, and an n+ diffusion, a source node, in a DNW (Deep N-Well) instead of an NMOS transistor with the big channel width as a program select device. Blowing of the proposed cell is done through the parasitic junction formed in the NMOS transistor in the program mode. Sensing failures of '0' data are removed because of removed contact voltage drop of a diode since a NMOS transistor is used instead of the junction diode in the read mode. In addition, a problem of being blown for a non-blown eFuse from a read current through the corresponding eFuse OTP cell is solved by limiting the read current to less than $100{\mu}A$ since a voltage is transferred to BL by using an NMOS transistor with the small channel width in the read mode.

• The Journal of Korean Academy of Prosthodontics
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• v.32 no.2
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• pp.225-233
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• 1994

The restorations of the severely damaged teeth by post core have been increased with the developement of endodontic procedures. But high failure rates of these procedures being reported, various restorative modifications were induced for successful treatments. Cast post-core and prefabricated post with core buildups are choice of treatment. The main causes of failure of the restorations are the fracture of post and core, root fracture, and recurrent caries due to microleakage. Recently, the acid etching technique and the use of dentin bonding agent at tooth surface to reduce the possible microleakage at the tooth-restoration interfaces were introduced. The object of this study was to measure and compare the microleakage by the types and cementation methods of post-core. For this study, forty extracted human anterior teeth were selected for specimen. After cleansing and routine endodontic procedures, anatomic crowns of each specimen were removed at the level of 2mm above the cementoenamel junction. Canals were preparated for post insertion and specimens were divided into four groups randomly. Post-cores were fabricated according to method for each group. Microleakage was measured by length of dye penetration at the tooth-restoration interfaces with measuring microscope at 50 magnification. Oneway ANOVA and t-test were performed for statistical analysis of resulting data. The following results were obtained from this study. 1. There wert significant statistical differences in degree of microleakage between each group (p<0.01). 2. Cast post-core cemented with ZPC (Group I) showed the most severe microleakage pattern$(1.5547{\pm}0.0872mm)$, and cast post-core cemented with adhesive resin cement after tooth surface treatment with dentin bonding agent (Group II) showed the least microleakage $(0.1497{\pm}0.0872mm)$. 3. Group IV revealed less dye penetrations than group III, but no statistical significance was seen between two groups.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.1 s.34
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• pp.9-16
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• 2005

This paper presents the development of new anisotropic conductive adhesives with enhanced thermal conductivity for the wide use of adhesive flip chip technology with improved reliability under high current density condition. The continuing downscaling of structural profiles and increase in inter-connection density in flip chip packaging using ACAs has given rise to reliability problem under high current density. In detail, as the bump size is reduced, the current density through bump is also increased. This increased current density also causes new failure mechanism such as interface degradation due to inter-metallic compound formation and adhesive swelling due to high current stressing, especially in high current density interconnection, in which high junction temperature enhances such failure mechanism. Therefore, it is necessary for the ACA to become thermal transfer medium to improve the lifetime of ACA flip chip joint under high current stressing condition. We developed thermally conductive ACA of 0.63 W/m$\cdot$K thermal conductivity using the formulation incorporating $5 {\mu}m$ Ni and $0.2{\mu}m$ SiC-filled epoxy-bated binder system to achieve acceptable viscosity, curing property, and other thermo-mechanical properties such as low CTE and high modulus. The current carrying capability of ACA flip chip joints was improved up to 6.7 A by use of thermally conductive ACA compared to conventional ACA. Electrical reliability of thermally conductive ACA flip chip joint under current stressing condition was also improved showing stable electrical conductivity of flip chip joints. The high current carrying capability and improved electrical reliability of thermally conductive ACA flip chip joint under current stressing test is mainly due to the effective heat dissipation by thermally conductive adhesive around Au stud bumps/ACA/PCB pads structure.

• Journal of Korean Foot and Ankle Society
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• v.12 no.1
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• pp.59-65
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• 2008

Purpose: To evaluate the results of anterolateral thigh perforator free flap for reconstruction of foot and ankle in old diabetic patients. Materials and Methods: Fifteen diabetic foot ulcer patients over the age of 55 were operated with anterolateral thigh perforator free flap. Hematological, hemodynamic, diabetic, bacteriologic and radiologic tests were checked with examination of blood vessel state in both the donor site and the recipient site. After surgery, serial check-up was performed at 6 week, 6 month, and 1 year postoperatively on the survival of transplantation tissue, condition of foot, and condition of walking. Results: There are one case of transplantation failure and four cases of partial tissue-necrosis. Delayed wound-healing was observed both recipient and donor tissue sites. At the final follow up, three cases of small ulcer were found at junction of flap and recipient tissue in plantar area. Fourteen out of fifteen patients could walk without any brace or walking aids. Conclusion: Reconstruction of foot and ankle region in old diabetic patients with the anterolateral thigh perforator free flap is a useful method which can prevent the amputation of foot and ankle.

• Journal of Chest Surgery
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• v.17 no.4
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• pp.819-828
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• 1984

Between September 1973 and December 1983, 61 patients with carcinoma of the esophagus were treated surgically at the Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital. Among 61 patients, male patients were 51 cases, female 10 cases and the age ranged from 21 years old to 72 years old with the average of 54.6 years old. Min symptoms of esophageal cancer were dysphagia (91.5%), weight loss (40.4%), pain(27.6%), and the average symptom duration was 3.85 months. The anatomical locations of esophageal cancer in preoperative esophagogram revealed 41.7% in middle 1/3, 8.3% in esophagograstic junction or cardia. Among 61 cases, 9 cases were managed by feeding gastrostomy due to inoperability, 8 cases by exploratory thoracotomy or lapatotomy only without curative or palliative resection, and 44 cases by curative or palliative resection with reconstruction. Among 52 cases of exploration, 44 cases were managed with curative or palliative resection of cancer and the resectability revealed 84.6% in operated cases. Among palliative or curative resected group, the esophagogastrostomy was performed in 40 cases (90.9%), esophagojejunostomy in 3 cases(6.8%), esophagectomy only in 1 case(2.3%). Postoperative complications were noticed in 12 cases, such as anastomotic leakage in 7 cases(15.6%), empyema in 2 cases (4.4%), respiratory failure in 2 cases (4.4%), anastomotic stricture in 1 case (2.2%). among 7 postoperative anastomotic leakage, 2 patients died as a result of that complication and the operative mortality revealed 4.3%. During follow-up work, the mean survival period was 19.3 months in patients who discharged hospital alive, and the 2 year survival rate was 34.6%.

• Proceedings of the KSRS Conference
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• v.1
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• pp.220-223
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• 2006

The COMS(Communication, Ocean and Meteorological Satellite) EPS(Electrical Power Subsystem) is derived from an enhanced Eurostar 3000 EPS which is fully autonomous operation in normal conditions or in the event of a failure and provides a high level of reconfiguration capability and flexibility. This paper introduces the COMS EPS preliminary design result. The COMS EPS consists of a battery, a solar array wing, a PSR(Power Supply Regulator), a PRU(Pyrotechnic Unit), a SADM(Solar Array Drive Mechanism) and relay and fuse brackets. This can offer a bus power capability of 3 kW. The solar array is made of a deployable wing with two panels. One type of solar cells is selected as GaAs/Ge triple junction cells. Li-ion battery is base lined with ten series cell module of five cells in parallel. PSR associated with battery and solar array generates a power bus fully regulated 50 V. Power bus is centralised protection and distribution by relay and fuse brackets. PRU provides power for firing actuators devices. The solar array wing is routed by the SADM under control of the AOCS(Attitude Orbit Control Subsystem). The control and monitoring of the EPS especially of the battery, is performed by the PSR in combination with on-board software.