• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.125.1-125.1
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• 2010

A high efficiency polymer electrolyte membrane (PEM) fuel cell stack was developed for pressurized pure hydrogen and oxygen supplying conditions. The design objective for the cell stack was to maximize the electric efficiency and to minimize exhaust-gas emissions from it simultaneously. To achieve this objective, the cell stack was designed to use pure hydrogen and oxygen as fuel and oxidant, respectively, and to be operated under high gas inlet pressures and in a stage-wise dead-end operation mode. Major components constituting the cell stack, such as membrane electrode assembly, bipolar-plate, and gasket, have been developed to meet a target durability even in severe operating conditions: high gas inlet pressures and usage of pure oxygen. A high-power fuel cell stack was assembled using these components to verify the performance. The cell stack showed a good performance in terms of the efficiency and maximum power output.

• Smart Structures and Systems
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• 제16권6호
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• pp.1069-1089
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• 2015

Arch bridges consist of some important components for structural behavior such as arches, sidewalls, filling materials and foundations. But, arches are the most important part for this type of bridges. For this reason, investigation of arch is come into prominence. In this paper, it is aimed to investigate the arch thickness effect on the structural behavior of masonry arch bridges. For this purpose, Goderni historical arch bridge which was located in Kulp town, Diyarbakir, Turkey and the bridge restoration process has still continued is selected as an application. The construction year of the bridge is not fully known, but the date is estimated to be the second half of the 19th century. The bridge has two arches with the 0.52 cm and 0.69 cm arch thickness, respectively. Finite element model of the bridge is constructed with ANSYS software to reflect the current situation using relievo drawings. Then the arch thickness is changed by increasing and decreasing respectively and finite element models are reconstructed. The structural responses of the bridge are obtained for all arch thickness under dead load and live load. Maximum displacements, maximum-minimum principal stresses and maximum-minimum elastic strains are given with detail using contours diagrams and compared with each other to determine the arch thickness effect. At the end of the study, it is seen that the maximum displacements, tensile stresses and strains have a decreasing trend, but compressive stress and strain have an increasing trend by the increasing of arch thickness.

• Membrane and Water Treatment
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• 제11권3호
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• pp.223-229
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• 2020

Here magnetic iron oxide particles (MIOPs) were synthesized under atmospheric air and which size was controlled by regulating the flow rate of alkali addition and used for efficient removal of bovine serum albumin (BSA) from water. The MIOPs were characterized using field-emission scanning electron microscopy (FE-SEM), Fourier transformation-Infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM). The results revealed a successful preparation of the MIOPs. The removal efficiency for BSA using MIOPs was found to be about 100% at lower concentrations (≥ 10 mg/L). The maximum adsorption of 64.7 mg/g for BSA was achieved as per the Langmuir adsorption model. In addition, microfiltration membrane for removal of BSA as model protein organic foulant is also studied. The effect of various MIOPs adsorbent sizes of 210, 680 and 1130 nm on the absorption capacity of BSA was investigated. Water permeability of the BSA integrated with the smallest size MIOPs membrane was increased by approximately 22% compared by the neat BSA membrane during dead-end filtration. Furthermore, the presence of small size MIOPs were also effective in increasing the permeate flux.

• 한국도서관정보학회지
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• 제21권
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• pp.325-361
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• 1994

The Library of Congress' proposal to license LC MARC database and the following debate over the proposal shows that the issue on ownership of bibliographic databases, which surfaced as a topic of concern in the international library community with the OCLC's a n.0, pplication for copyright of its databases in 1982, is not fading or dead into the 1990s. In particular, the way that technological developments are outpacing the ability of the relevant organizations and legal systems to make necessary adjustments is giving the library profession a warning that cooperative efforts for further development of the international library systems, such as the UBC program, might be seriously impeded without a swift and amicable agreement on the controversial 'database ownership' issue. Here, the purpose of this paper lies in discussing the 'database ownership' issue from a macro and long-term perspective, with emphasis on its potential impacts on, and implications for, international information flows. To the end, the specific questions covered in this paper include : 1) what are the major causes of the database ownership controversy? 2) what are the potential impacts of the database ownership issue on the library profession's cooperative efforts toward free bibliographic information flows at the international level? And finally, 3) what are the implications of the database ownership issue for the Korean Library Community, which is making efforts toward the establishment of a national library network in near future through linking various library automation systems.

• 한국문헌정보학회지
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• 제42권3호
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• pp.259-279
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• 2008

신학 분야의 시소러스를 구축하는 전 단계로서, 패싯을 이용하여 신학 용어를 분류하였다. 영어로 된 신학 사전에서 1.031개의 용어를 선정하였고, 이 중에서 실제로 분류한 용어의 수는 984개이다. 용어를 분류하기 위해서 전개한 패싯은 기본 패싯 7개와 하위 패싯 14개이었다. 분류한 용어들을 분석해 본 결과, 신학 분야의 특성에 맞게 물리적 형태를 갖는 구체적인 용어의 수보다 추상적인 용어의 수가 많았으며. 전체 용어 수의 70% 정도를 차지하였다. 문헌 분류를 위한 십진 분류 체계에 대한 연구가 한계에 이른 상황에서. 이러한 특정 주제 분야의 용어를 분류하고 시소러스를 구축하는 연구가 더 활발해져야 한다고 생각한다.

• 지능정보연구
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• 제6권2호
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• pp.29-40
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• 2000

Process planning (selection and ordering of processes) and material selection for product manufacturing are two key things determined before taking full-scale manufacturing. Knowledge on product design. material characteristics, processes, time and cost all-together are mutually related and should be considered concurrently. Due to the complexity of problem, human experts have got only one of the feasilbe solutions with their field knowledge and experiences. We propose a hierarchical expert system framework of knowledge representation and reasoning in order to overcome the complexity. Manufacturing processes have inherently hierarchical relationships, from top level processes to bottom level operation processes. Process plan of one level is posted in process blackboard and used for lower level process planning. Process information on blackboard is also used to adjust the process plan in order to resolve the dead-end or inconsistency situation during reasoning. Decision variables for process, material, tool, time and cost are represented as object frames, and their relationships are represented as constraints and rules. Constraints are for relationship among variables such as compatibility, numerical inequality etc. Rules are for causal relationships among variables to reflect human expert\`s knowledge such as process precedence. CRSP(Constraint and Rule Satisfaction Problem) approach is adopted in order to obtain solution to satisfy both constraints and rules. The trade-off procedure gives user chances to see the impact of change of important variables such as material, cost, time and helps to determine the preferred solution. We developed the prototype system using visual C++ MFC, UNIK, and UNlK-CRSP on PC.

• Structural Engineering and Mechanics
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• 제50권4호
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• pp.419-439
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• 2014

In this study, the structural performance of a seven span masonry arch bridge was evaluated. Investigations were performed on Aspendos (Belkis) Masonry Arch Bridge which was located on road of Aspendos Acropolis City in Antalya, Turkey. The old bridge was constructed in the early of fourth century AD, but it was exposed to the earthquakes in this region and the overloading by the river water. The old bridge was severely damaged and collapsed by probably an earthquake many years ago and a new bridge was then reconstructed on the remains of this old bridge by Seljuk in the 13th century. The bridge has also been affected from overflowing especially in the spring of each year, so some protective measures should be taken for this monumental bridge. Therefore, the structural performance under these loading has to be known. For this purpose, an initial finite element model was developed for the bridge and it was calibrated according to ambient vibration test results. After that, it was analyzed for different load cases such as dead, live, earthquake and overflow. Three load combinations were taken into account by deriving from these load cases. The displacements and the stresses for these combination cases were attained and compared with each other. The structural performance of Aspendos Masonry Arch Bridge was determined by considering the demand-capacity ratio for the tensile stress of the mortar used in Aspendos Masonry Arch Bridge. After these investigations, some concluding remarks and offers were presented at the end of this study.

• Membrane and Water Treatment
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• 제11권2호
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• pp.131-139
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• 2020

The current study focused on the preparation of low-cost PVC-based adsorbing membrane. Metakaolin, as available adsorbent, was embedded into the PVC matrix via solution blending method. The as-prepared PVC/metakaolin mixed matrix membranes were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), pure water permeability and contact angle measurements. The results confirmed the improvement of PWP and hydrophilicity due to the presence of metakaolin in the PVC matrix. Additionally the structure of PVC membrane was changed due to the incorporation of metakaolin in the polymer matrix. The static adsorption capacity of all samples was determined through dye removal. The effect of metakaolin dosage (0-7%) and pH (4, 8, 12) on dye adsorption capacity was investigated. The results depicted that the highest adsorption capacity was achieved at pH of 4 for all samples. Additionally, adsorption data were fitted on Langmuir, Freundlich, and Temkin models to determine the appropriate governing isotherm model. Finally, the dynamic adsorption capacity of the optimum PVC/metakaolin membrane was studied using dead-end filtration cell. The dye removal efficiency was determined for pure PVC and PVC/metakaolin membrane. The results demonstrated that PVC/metakaolin mixed matrix membrane had a high adsorption capacity for dye removal from aqueous solution.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.521-523
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• 2005

A Jumper wire is currently used to connect each fixed power line on both sides of dead end tower for overhead transmission line, but in case of a jumper wire swing under circumstances of typhoon, etc. and the air clearance is deficient then a flashover fault may Happen. Now the angle tower has the jumper support string to prevent a swing of jumper wire and to secure the air clearance between jumper wire and tower main body, but the flashover fault by swing of jumper wire was happened yl times across all over the country, because of the typhoon 'Rusa' in year 2002 and 'Maemi' in year 2003. This paper presents the design and development of 'Counter Weight' which enables to keep the swing angle of jumper wire under 40 degree in design condition to prevent a flashover fault by swing of jumper wire by a high wind pressure load in case of typhoon and have completed a mechanical and electrical characteristic test.

• Journal of Chest Surgery
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• 제26권3호
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• pp.224-227
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• 1993

We experienced one case of orthotopic cardiac transplantation in a patient with end stage dilated cardiomyopathy. This 50 year-old female recipient was suffered from NYHA functional class IV cardiac failure and dependent upon intravenous inotropic support for 2 months [recipient category 1]. Her preoperative condition was grave with left ventricular ejection fraction of 20% and estimated systolic pulmonary arterial pressure [from Doppler study] was 50mmHg. The brain-dead donor was 31 year-old male with head trauma. The body sizes [weight, height] of the donor/recipient were 70 Kg, 165 cm / 43 Kg, 160 cm and appropriately overmatched. Preoperatively, identical ABO/Rh blood group [A+] and nonreacting HLA crossmatching were confirmed. On November 11 1992 cardiac transplantation was performed without complication. Multiple organ procurement team and heart transplantation team were organized the operation schedule appropriately to minimize the ischemic time. The pump time was 126 minutes and aortic crossclamping time of recipient heart was 73 minutes and, as a result, total ischemic time of the transplanted heart was 75 minutes. Postoperatively, the vital signs were stable with minimal inotropic support. The immunosuppressive therapy was commenced from preoperatively and cyclosporine, azathioprine, and corticosteroid were used as a combination therapy as scheduled and monitored with blood drug concentration, WBC count, renal function and most importantly regular endomyocardial biopsy.Now, 5 months after transplantation, the patient is in NYHA functional class II with minimal cardiac drug support.