• Journal of Chest Surgery
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• v.43 no.5
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• pp.513-517
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• 2010

Background: Diaphragmatic plication through a thoracoscopic approach has been an effective modality to treat diaphragmatic enventration. However, the conventional technique for thoracoscopic plication has some disadvantages. We have developed an improved and simplified technique with utilizing the head up position, $CO_2$ insufflation and figure-of-eight sutures. Material and Method: Between October 2005 and September 2009, 9 patients with diaphragmatic paralysis underwent repair using our modified technique. The mean patient age was $38.5{\pm}53.0$ years (range: 2~76 years). Result: The mean operation time was $46.7{\pm}15.9$ min (range: 30~85 min). None of the patients died due to this procedure, but there was one case of prolonged air leakage, and a case of re-expansion pulmonary edema, which required 3 days of ventilator support after the procedure. The mean hospital stay was $6.22{\pm}2.04$ days (range: 4~11 days). The mean follow-up duration was $27.2{\pm}11.6$ months (range: 2~43 months). All the patients had their symptoms relieved and there was no recurrence of eventration except for one patient who developed more than 2 cm elevation of the diaphragm compared to the immediate post-operation status. Conclusion: With our technique, thoracoscopic diaphragmatic plication was feasible via using only three 5 mm ports and without a working window and the midterm results were favorable. Therefore, we advocate thoracoscopic diaphragmatic plication as a preferred technique to the conventional open plication technique.

• Journal of the Korean Institute of Gas
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• v.16 no.6
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• pp.34-40
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• 2012

The fuel cell is one of the renewable energy sources. And it is a new source of energy that can be applied to various fuels and continuously supported by the excellent city-gas infrastructure. It is important to improve performances and reliabilities, and reduce the cost of fuel cell systems for commercialization. And, some safety performances of blower domestically produced are evaluated and some improvements are researched to save the cost of fuel cell systems. In this paper, the performance and worst stress condition of blowers are evaluated in operating environment similar to the fuel cell systems. Actually, the correlation of flow, leakage and thermal behavior are evaluated in the worst stress condition at $70^{\circ}C$ and, some major factors of blower degradation such as a motor deterioration, material and structures of the outlet are examined.

• Journal of Chest Surgery
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• v.35 no.5
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• pp.392-396
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• 2002

Background: Video-thoracoscopy is known to be an useful method to provide accurate pre-resectional staging in patients with lung cancer in addition to the conventional radiologic studies and mediastinoscopy, for the pleural cavity is inspected directly and biopsy specimens call be obtained. This study is undertaken to evaluate how video-thoracoscopy can be used in deciding pre-resectional stage Material and Method: Video-thoracoscopy was performed in patients with lung cancer who were scheduled for surgical resection based on the radiologic staging and mediastinoscopic biopsy. 37 patients were included in this study. Pre-thoracoscopically 18 cases were in TNM stage 1, 7 in stage 2, and 12 in stage 3. Result: In 15 of 37 cases, video-thoracoscopy could not be performed effectively due to heavy adhesions in the pleural cavity, diaphragmatic and chest wall invasion of tumor and bulky tumor mass es. Mediastinal lymph nodes were positive postresectionally in 6 of these 15 cases. In 22 cases, video-thoracoscopy was performed as usual. Positive mediastinal lymph nodes were identified in 2 cases and exploratory thoracotomy was prevented. Surgical resection were carried out in remaining 20 cases and 5 cases among them had positive mediastinal lymph nodes. Conclusion: We believe that it is difficult to perform pre-thoracotorny video-thoracoscopy for all lung cancer patients for there were many cases that thoracoscory could not be undertaken doe to heavy adhesions in the pleural cavity, tumor involvement of the chest wall and/or diaphragm and bulky tumor mass. However we think it is helpful in preventing unnecessary exploratory thoracotomy for some patients with lung cancer whom pre-thoracotomy video-thoracoscopy was carried out.

• Journal of Energy Engineering
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• v.24 no.2
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• pp.34-39
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• 2015

This study confirmed the characteristics of hydrogen production according to electrode materials by producing non-diaphragm alkaline water electroanalyzer that can be controlled at medium temperature to produce hydrogen. As a result of the electrochemical characteristics by electrode material ($IrO_2/Ti$, $RuO_2/Ti$, Ti), the highest efficiency was found in $RuO_2/Ti$, as a result of hydrogen production experiment by electrolyte concentration, electrolyte concentration has a tendency to be proportional to hydrogen production and the condition of 30% KOH showed the highest hydrogen production as $118.9m^3/m^3/day$. In the experiment that confirmed hydrogen production according to electrode materials, in case of combination of anode ($IrO^2/Ti$) and cathode ($RuO^2/Ti$), it was $157.55m^3/m^3/day$ that showed a higher hydrogen production by around 6.97% than that of $IrO^2/Ti$ and cathode. It is presumed that the improvement of electrochemical activation of DSA electrode increases hydrogen production and influences the improvement of durability compared to the former electrode so that it enables stable alkaline water electrolysis.

• Journal of Chest Surgery
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• v.43 no.1
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• pp.47-52
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• 2010

Background: Traumatic diaphragmatic rupture is not common, but it requires swiftly performing an emergency operation. This study was conducted to evaluate the prognostic factors for mortality after surgically treating traumatic diaphragmatic rupture. Material and Method: From Jan 2001 to Dec. 2008, we experienced 37 cases of multiple traumas with diaphragmatic injuries that were confirmed by surgical procedures. We evaluated various factors, including the type of injury, the associated injuries, the preoperative vital signs, the ISS, the time until surgery and the rupture size. Result: There were 30 patients with blunt trauma and 7 patients with penetrating trauma. Thirty-four patients had associated injuries and the mean ISS was 20.8. Postoperative complications occurred in 11 patients and hospital mortalities occurred in 6 patients. The prognostic factors that had an influence on the postoperative mortalities were the preoperative intubation state, the patient who exhibited hypotension and a high ISS. Conclusion: Traumatic diaphragmatic rupture is just one part of multiple traumas. The postoperative mortalities might depend on not only on the diaphragmatic rupture itself, but also on the severity of the associated injuries.

• Journal of the Korean Electrochemical Society
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• v.2 no.1
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• pp.17-22
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• 1999

Since the use of porous silicon for microsensors and microactuators is in the euly stage of study, only several application devices, such as light-emitting diodes and chemical sensors have so far been demonstrated. In this paper we present an overview of the present status of porous silicon sensors and actuators research with special emphasis on the applications of chemical sensors and optical devices. The capacitive type porous silicon humidity sensors had a nonlinear capacitance-humidity characteristic and a good sensitivity at higher humidity above $40\%RH$. The porous silicon $n^+-p-n^+$ device showed a sharp increase in current when exposed to an ethanol vapor. The $p^+-PSi-n^+$ diode fabricated on porous silicon diaphragm exhibited an optical switching characteristic, opening up its utility as an optical sensor or switch. The photoluminescence (PL) spectrum, taken from porous silicon under 365 nm excitation, had a broad emission, peaked at -610 nm. The electroluminescence(EL) from ITO/PSi/In LED had a broader spectrum with a blue shifted peak at around 535nm than that of the PL.

• Journal of Chest Surgery
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• v.32 no.12
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• pp.1065-1077
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• 1999

Background : Ventricular assist devices(VADs) are being used for patients in postcvardiotomy cardiogenic shock status bridge to cardiac transplant settings and in post-myocardial infarction cardiogenic shock. The VAD which was developed at the Deparment of medical engineering in Dankook University College of Medicine was a pneumatically driven device and can maintain pulsatile flow. The goal of this study is to develop animal experimental models using the VAD and to clarify the reliability and hemodynamic property adequacy of end organ perfusion durability and severity of thrombotic-hemolytic tendency of the device. Material and Method : The pneumatic VAD was applied to 8 adult female lambs, We examined some hemodynamic parameters such as arterial blood pressure pulmonary capillary wedge pressure(pcwp) pulmonary artery pressure(PAP) left atrial pressure hour urine output cardiac index VAD flow EKG to determine the reliability of the VAD and hemodynamic compatibility of the experimental animals within 24 hours of experiment. We also observed the end organ perfusion durability of the VAD and thrombotic-hemolytic property of the VAD after 24 hours of VAD insertion. Result: We could monitor all hemodynamic parameters including pcwp PAP cardiac index EKG, adn hour urine as true clinical settings. We observed that the reliability of the VAD was excellent and the hemodynamic property of the experimental animal and end organ perfusion were adequate within 24 hours of experiment. In four lambs surviving 24 hours after insertion the reliability of the VAD and end organ perfusion were excellent and no thrombotic-hemolytic tendency was noted. However after 15 days of experiment the diaphragm of the VAD was torn and it was recommende that the durability of the VAD should be extended. Conclusion : e conclude that the pneumatic VAD developed at Dankook University Biomedical Engineering has good hemodynamic property and low thromboembolic tendency and presents adequate end organ perfusion but we noted that the durability of the device should be expanded further. It will be possible to do more reliable experiment in the future according to the animal experimental method developed in this study especially with the heart failure models.

• Journal of the Korean Geosynthetics Society
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• v.22 no.3
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• pp.87-95
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• 2023

Recently, redevelopment of the original downtown area is underway, the necessity of construction in adjacent location is increasing. However, excavations in dense urban areas are prone to ground problems due to various causes, so it is necessary to use materials and methods that can minimize such problems. As a general earth retaining method, various methods such as diaphragm wall and CIP method are applied using cement. However, since a large amount of cement is used for the installation of earth retaining method, it is necessary to conduct research on the development of new cement substitute materials to significantly reduce greenhouse gas emissions. In this study, we utilized the hardening reaction of blast furnace slag powder, desulfurized gypsum and high calcium fly ash by alkali activation and applied it to the SCW method. As a result, it was analyzed that the compressive strength of solidified soil using development solidification material was 96.2 ~ 106.3% of OPC at 28 days of curing. In addition, the strength increment ratio was 2.06 for sandy soil and 2.41 for clayey soil, which was higher than 1.85 of OPC. It seems an advantageous in terms of long-term strength. In addition, from the environmental point of view, it was analyzed that there is no elution of heavy metals and that greenhouse gas emissions can be dramatically reduced. Therefore, if further studies are conducted, it can be applied to the SCW method.