• Journal of Chest Surgery
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• v.11 no.2
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• pp.170-174
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• 1978

A case of mediastinal seminoma is presented. A male driver, 27 years old Korean, has been suffered from substernal pain, cough and moderate swallowing difficulty since 5 months prior to this admission. At the time of onset, he visited at a local clinic to find some mass in his anterior mediastinum on chest P-A and lateral X-ray check. Recently, intermittent hiccups with much aggravated dysphagia forced him to visit our hospital, and admitted for radical resection under the impression of anterior superior mediastinal tumor of thymus origin. Median sternotomy was done and total resection of the tumor of 8.0X11.0X3.5cm was done without any specific complication and biopsy of the tumor revealed as primary mediastinal seminoma of the mediastinum. Supplementary prophylactic irradiation therapy was done with a tumor dose of 4,000 rad in 4 weeks after operation. Postoperative hospital course was uneventful and patient was joyful with his occupation for 3 months after discharge.

• Journal of the Korean Professional Engineers Association
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• v.42 no.5
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• pp.41-45
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• 2009

The last century of lighting has been dominated by incandescent, fluorescent and high-intensity discharge(HID)light sources. In the late 1970's, after green LEDs were invented, Dr. Ching Tang at Eastman Kodak discovered that sending an electrical impulse through carbon compound caused such material glow. Present day LED commercial packages have reached 100 lm/W, comparable to the efficacies of fluorescent and certain HID lamps. LED products available today are market as "Green-Industry" but actually low light output compared to typical light sources. The combination of high price and low light output make them a poor replacement for current technology. It is very important to compare new LED products to the most efficient conventional technology that could be used for any specific application. As LED technology advances, costs decrease, and efficiency improves, LEDs will build market share in the general illumination market.

• Journal of Chest Surgery
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• v.20 no.2
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• pp.317-322
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• 1987

Records of 15 patients who underwent operation for constrictive pericarditis at this department from 1976 through 1984 were reviewed. All had hemodynamically significant pericardial constriction preoperatively, and pericardial disease was confirmed at operation. There were 12 males and 3 females in this series. Range of age varied from 7 years to 51 years. Clinical and histological study revealed granulomatous pericarditis compatible with the diagnosis of tuberculosis in 5 patients, non-specific chronic inflammatory changes in 6 patients and pyogenic pericarditis in 2 patients. Pericardiectomy was performed through a median sternotomy [11 cases] or bilateral anterior thoracotomy [4 cases]. The postoperative complications were observed in 4 patients. Low cardiac output was the most common complication [2 patients]. In 13 cases, excluding 2 operative deaths, preoperatively all were in New York Heart Association Class III or IV. At the time of discharge II [85%] were in Class I or II. 4 Cases were reoperated after original pericardiostomy and all resulted in marked improvement. Early surgical intervention is advisable in all patients in whom cardiac constriction is caused by either a thickened pericardium or a pericardial effusion before myocardial dysfunction occurs.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.423-426
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• 1996

The conditions to be satisfied with SOC(State-of-Charge) indicator installed on the electric vehicle were that it should be used under frequent loading conditions and that it should enable the monitor to adjust to the aging effect. But, the state-of-charge test requires a lengthy stabilization period after discharge cycles and the ampere-hour test requires the knowledge of the battery capacity in terms of amp-hours. However, a monitoring technique combining the state-of-charge test to enable the monitor to adjust to the aging effect with the ampere-hour test to use under frequent loading condition is studied and implemented on a microcontroller-based circuit in this paper. Specially, optical fiber is used to realize hydrometer which is immune to electromagnetic interference and toxic environment and makes it possible to be used in a wide temperature range.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.930-933
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• 2001

Titanium Alloys used in this experiment has an good corrosion resistance and specific strength, and is the new material developed for medical supplies living goods. In this study the rolled titanium alloy is done by annealing, solution heat-treatment and aging and then is worked by wire EDM. With changing the process conditions, the process properties of surface hardness, surface roughness, shape of process surface and the analysis of ingredients are measured through experiment repeating main cut and finish cut. It is confirmed to gain good measure values as increasing the number of processing of wire EDM. In this experiment the phenomena of processing is studied and the appropriate process condition is proposed.

• Carbon letters
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• v.13 no.3
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• pp.157-160
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• 2012

In this work, iron oxide ($Fe_3O_4$) nanoparticles were deposited on multi-walled carbon nanotubes (MWNTs) by a simple chemical coprecipitation method and $Fe_3O_4$-decorated MWNTs (Fe-MWNTs)/polypyrrole (PPy) nanocomposites (Fe-MWNTs/PPy) were prepared by oxidation polymerization. The effect of the PPy on the electrochemical properties of the Fe-MWNTs was investigated. The structures characteristics and surface properties of MWNTs, Fe-MWNTs, and Fe-MWNTs/PPy were characterized by X-ray diffraction and X-ray photoelectron spectroscopy, respectively. The electrochemical performances of MWNTs, Fe-MWNTs, and Fe-MWNTs/PPy were determined by cyclic voltammetry and galvanostatic charge/discharge characteristics in a 1.0 M sodium sulfite electrolyte. The results showed that the Fe-MWNTs/PPy electrode had typical pseudo-capacitive behavior and a specific capacitance significantly greater than that of the Fe-MWNT electrode, indicating an enhanced electrochemical performance of the Fe-MWNTs/PPy due to their high electrical properties.

• ETRI Journal
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• v.38 no.2
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• pp.252-259
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• 2016

Di(1-aminopyrene)quinone (DAQ) as a quinone-containing conducting additive is synthesized from a solution reaction of 1-aminopyrene and hydroquinone. To utilize the conductive property of DAQ and its compatibility with activated carbon, a composite electrode for a supercapacitor is also prepared by blending activated carbon and DAQ (3:1 w/w), and its supercapacitive properties are characterized based on the cyclic voltammetry and galvanostatic charge/discharge. As a result, the composite electrode adopting DAQ exhibits superior electrochemical properties, such as a higher specific capacitance of up to $160F{\cdot}g^{-1}$ at $100mV{\cdot}s^{-1}$, an excellent high-rate capability of up to $1,000mV{\cdot}s^{-1}$, and a higher cycling stability with a capacitance retention ratio of 82% for the 1,000th cycle.

• Carbon letters
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• v.15 no.2
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• pp.113-116
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• 2014

Due to their morphology, electrochemical stability, and function as a conducting carbon matrix, graphene nanosheets (GNS) have been studied for their potential roles in improving the performance of sulfur cathodes. In this study, a GNS/sulfur (GNS/S) composite was prepared using the infiltration method with organic solvent. The structure, morphology and crystallinity of the composites were examined using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The electrochemical properties were also characterized using cyclic voltammetry (CV). The CV data revealed that the GNS/S composites exhibited enhanced specific-current density and ~10% higher capacity, in comparison with the S-containing, activated-carbon samples. The composite electrode also showed better cycling performance for multiple charge/discharge cycles. The improvement in the capacity and cycling stability of the GNS/S composite electrode is probably related to the fact that the graphene in the composite improves conductivity and that the graphene is well dispersed in the composites.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1685-1687
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• 1996

Recently, conducting polymer has been much attracted as novel materials because of its electronic behavior and functional application by doping process. In this paper, we electrochemically synthesized polyaniline films under potential sweep conditions, which exhibit high electric conductivity about 200 S/cm. Specific energy of 600 Wh/kg and Ah efficiency 98% were achieved during the charge/discharge cycling using liquid electrolyte system. On the other hand, consequences of the cycling were 260 Wh/kg and 95% Ah efficiency using polyethylene oxide(PEO) based solid-state electrolyte system.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1639-1640
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• 2015

These days most of countries concern about eco-friendly energy. With this trend, the interests for Electric Vehicles(EVs) have been increased not only for its eco-friendly characteristics but also for the possibility that it can be used as Distributed Generation(DG). However, in terms of using EVs as DG, it requires specific standards. If there is no regulation and many of EVs start to discharge, it could cause severe unstability in power system. As there is no proper standards or regulations of Vehicle-to-Grid(V2G) system, we suggest the development direction of standardization of V2G system in the Republic of Korea by examining other countries' V2G standards.