• 한국정밀공학회지
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• 제19권4호
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• pp.101-108
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• 2002

A specially-built EMM (Electrochemical Micro Machining) / PECM (Pulse Electrochemical Machining) cell, a electrode tool filled with non-conducting material, a electrolyte flow control system and a small & stable gap control unit are developed to achieve accurate dimensions of recesses. Two electrolytes, aqueous sodium nitrate and aqueous sodium chloridc arc applied in this study. The farmer electrolyte has better machine-ability than the latter one because of its appropriate changing to the transpassive state without pits on the surface of workpiece. It is easier to control the machining depth precisely by micrometer with pulse current than direct current. This paper also presents an identification method for the machining depth by in-process analysis of machining current and inter electrode gap size. The inter electrode gap characteristics, inc1uding pulse current, effective volumetric electrochemical equivalent and electrolyte conductivity variations, are analyzed based on the model and experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.218-220
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• 2008

Urban air quality, including carbon-dioxide emissions, and national energy security are related issues affecting the rail industry and transportation sector as a whole. They are related by the fact that (in the United States) 97-98% of the energy for the transport sector is based on oil, and more than 60% is imported. A fuelcell locomotive combines the environmental advantages of a catenary-electric locomotive with the higher overall energy efficiency and lower infrastructure costs of a diesel-electric. Catenaryelectric locomotives, when viewed as only one component of a distributed machine that includes an electricity-generating plant and transmission lines, are the least energy-efficient locomotive type. The natural fuel for a fuelcell is hydrogen, which can be produced from many renewable energies and nuclear energy, and thus a hydrogen-fuelcell locomotive will not depend on imported oil for its energy supply. This paper proposes a base models of Hybrid fuel cell/IPT railway vehicle power system, the necessary of this research.

• Bioinformatics and Biosystems
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• 제2권1호
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• pp.28-32
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• 2007

The protein phosphorylation is one of the important processes in the cell signaling pathway. A variety of protein kinase families are involved in this process, and each kinase family phosphorylates different kinds of substrate proteins. Many methods to predict the kinase-specific phosphoryrated sites or different types of phosphorylated residues (Serine/Threonine or Tyrosin) have been developed. We employed Supprot Vector Machine (SVM) to attempt the prediction of protein kinase specific phosphorylation sites. 10 different kinds of protein kinase families (PKA, PKC, CK2, CDK, CaM-KII, PKB, MAPK, EGFR) were considered in this study. We defined 9 residues around a phosphorylated residue as a deterministic instance from which protein kinases determine whether they act on. The subsets of PSI-BALST profile was converted to the numerical vectors to represent positive or negative instances. When SVM training, We took advantage of multiple SVMs because of the unbalanced training sets. Representative negative instances were drawn multiple times, and generated new traing sets with the same positive instances in the original traing set. When testing, the final decisions were made by the votes of those multiple SVMs. Generally, RBF kernel was used for the SVMs, and several parameters such as gamma and cost factor were tested. Our approach achieved more than 90% specificity throughout the protein kinase families, while the sensitivities recorded 60% on average.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.44.1-44.1
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• 2010

poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a bacterially derived copolymer produced by fermentation. PHBV has been attractive because of its potential environmental, pharmaceutical and biomedical applications. Recently, the electrospinning technique has been used to fabricate fibrous mat for biomedical applications such as artificial blood vessel, drug release and scaffolds, because this method is simple and easy to get ultrafine polymer fibers. Depending on speed of rotation drum collector, fiber structure was different. In this work, PHBV fiber was aligned by electrospinnning machine. Furthermore, alignment of PHBV fiber mats was given angle such as $45^{\circ}$, $60^{\circ}$ and $90^{\circ}$. The morphology of each aligned PHBV fiber mat was observed by SEM technique. The mechanical property was evaluated depending on alignment angle. Especially, cell attachment ability depending on alignment of PHBV fiber mats was carried out using MG- 63 osteoblast like cells.

• 센서학회지
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• 제23권3호
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• pp.170-172
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• 2014

$CO_2$ sensor was used only one solid electrolyte in many cases. To improve the sensing characteristics of $CO_2$ sensors, solid electrolyte $CO_2$ sensor has been developed by bi-electrolyte type sensor using Na-Beta-alumina and YSZ. However, in many further studies, bi-electrolyte type sensor was made by pellet pressed by press machine and additional treatment for formation of interface. In the aspect of mass production, using thick film and additional treatment is not suitable. In this study, $CO_2$ sensor was fabricated by bi-electrolyte structure which was made by an NBA paste layer deposited on YSZ pellet and fired at $1650^{\circ}C$ for 2 hour. The formation of stable interface between YSZ and NBA were confirmed by SEM image. When the type IV electrochemical cell arrangement represented by $CO_2,O_2,Pt{\mid}Li_2CO_3-CaCO_3{\parallel}NBA{\parallel}YSZ{\mid}O_2,Pt$ is used to measure the $CO_2$ concentration in air. This sensor EMF should depend only on the concentration of $CO_2$ by logarithmic. Also, sensor shows $P_{CO_2}$ and EMF relationship like nerstian reaction at a temperature of $450^{\circ}C$.

• 한국환경복원기술학회지
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• 제15권2호
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• pp.41-56
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• 2012

Landscape space can and should play as a multi-functional agent : healing contaminated soil, reducing natural hazards, supporting living things, making comfortable environment for human, and appealing to human aesthetics, etc. This article aims to show the possibility and role of landscape space as such agent. In landscape design for National Marine Biology Resource Institute, distributed rain water treatment system and rain gardens are introduced to replace a mono-functioning large detention pond which was suggested by disaster impact assesment. Phytoremediation and vegetation filtering system with muti-cell wetlands are also adapted to heal the contaminated soil. This kind of landscape as a 'living machine' which can play as an operational control utility of multi-environment and thus can be combined effectively into green infrastructure is important for post-industrial city, especially in an era of climate change.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.988-989
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• 2006

The ultrasonic welding is with features of high electric conductivity and hot conductivity when it is used in metallic bond, high electric conductivity and hot conductivity when it is used in various metallic bonds, excellent quality when it is used for advanced junction, easiness when it is used in various metallic bonds, being needless for the exhaustive material and being benefit for the environment. Currently the use of ultrasonic welding is increasing in the industrial fields such as the automobile battle, the refrigerator, the air conditioner, the battery and the solar cell junction. But the production ability is insufficient in our country and it is necessary to explore the core technology of the ultrasonic welding. In this paper, the output LC resonance filter and 35kHz squal wave onion occurrence Full Bridge plans was designed. The output examination of the ultrasonic oscillator and the ultrasonic welding examination were done. The method for getting more smooth result in the ultrasonic welding machine system was researched.

• 한국정밀공학회지
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• 제31권5호
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• pp.375-380
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• 2014

To enhance biocompatibility between the orthopedic implant stem and obsteoblast cells, bone-forming cells, micro-size holes are patterned in Ti plate surface. Initially, the house built laser power stabilization system is applied to the laser micro patterning machine to convince repeatable result. Various pulse widths are irradiated Ti plate and relationship between diameters of patterned holes and pulsed width is derived. Effect of multi pulse is observed and optimal pulse number is considered to avoid heat affected zone. After MG-63 osbeoblast cells are cultured, micro patterned Ti plates are compared with control plates. In SEM image, cells are well aligned and aggregation is observed in both 60, and $100{\mu}m$ patterned plates. Finally, free form surface stem model is prepared to test micro hole patterning.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 춘계학술발표회
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• pp.501-502
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• 2005

During the cut and dismantling process of HANARO irradiated instrumented capsule(03M-06U), a little different phenomenon like a jamming was observed and occurred. So to release jamming between outer pipe and inner thermal media, the outer pipe will be cut piece by piece by capsule cutting machine installed in M2 hot cell until the outer pipe was eliminated or reduced as we could. It is assumed that this kind of problem was occurred following reasons: 1) This capsule has probably a problem during manufacturing process at shop before irradiation. 2) The gap between outer pipe and thermal media is not enough to meet design criteria for thermal expansion during irradiation at HANARO

• 한국공작기계학회논문집
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• 제17권2호
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• pp.1-6
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• 2008

In recent years, developments in the semiconductor and electronic industries have brought a rapid increase in the use of large size silicon wafer. For further improvement of the ultra precision surface and flatness of Si wafer necessary to high density ULSI, it is known that polishing is very important. However, most of these investigation was experiment less than 300mm diameter. Polishing is one of the important methods in manufacturing of Si wafers and in thinning of completed device wafers. This study reports the machining variables that has major influence on the characteristic of wafer polishing. It was adapted to polishing pressure, machining speed, and the slurry mix ratio, the optimum condition is selected by ultra precision wafer polishing using load cell and infrared temperature sensor. The optimum machining condition is selected a result data that use a pressure and table speed data. By using optimum condition, it achieves a ultra precision mirror like surface.