• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.171-171
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• 2009

The electrodes are usually made of a porous mixture of carbon-supported platinum and ionomers. $SnO_2$ particles provide as supports that have been used for DMFCs, and it have high catalytic activities toward methanol oxidation. The main advantage of $SnO_2$ supported electrodes is that it has strong chemical interactions with metallic components. The high activity to a synergistic bifunctional mechanism in which Pt provides the adsorption sites for CO, while oxygen adsorbs dissociative on $SnO_2$. The reaction between the adsorbed species occurs at the Pt/$SnO_2$ boundary. The morphological observations were characterized by FESEM and transmission electron microscopy (TEM). $SnO_2$ particles crystallinity was analyzed by the X-ray diffraction (XRD). The surface bonded state of the $SnO_2$ particles and electrode materials were observed by the X-ray photoelectron spectroscopy (XPS). The electric properties of the Pt/$SnO_2$ catalyst for methanol oxidation have been investigated by the cyclic voltametry (CV) in 0.1M $H_2SO_4$ and 0.1M MeOH aqueous solution. The peak current density of methanol oxidation was increased as the $SnO_2$ content in the anode catalysts increased. Pt/$SnO_2$ catalysts improve the removal of CO ads species formed on the platinum surface during methanol electro-oxidation.

• Bulletin of the Korean Chemical Society
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• v.25 no.9
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• pp.1371-1378
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• 2004

A porous stainless steel (SUS) as a substrate of silica composite membranes for hydrogen purification was used to improve mechanical strength of the membranes for industrial application. The SUS support was successfully modified by using submicron Ni powder, $SiO_2$ sols with particle size of 500 nm and 150 nm in turns. Silica top layer was coated on the modified supports under various preparation conditions such as calcination temperature, dipping time and repeating number of dipping-drying process. The calcination temperature for proper sintering was between H ttig temperature and Tamman temperature of the coating materials. Maximum hydrogen selectivity was investigated by changing dipping time. As repeating number of dipping-drying process increased, permeances of nitrogen and hydrogen were decreased and $H_2/N_2$ selectivity was increased due to the reduction of non-selective pinholes and mesopores. For the silica membrane prepared under optimized conditions, permeance of hydrogen was about $3\;{\times}\;10^{-5}\;cm^3{\cdot}cm^{-2}{\cdot}s^{-1}{\cdot}cmHg^{-1}$ combined with $H_2/N_2$ seletivity of about 20.

• Journal of Microbiology
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• v.42 no.2
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• pp.103-110
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• 2004

In order to understand the molecular basis of selective expression of stationary-phase genes by RNA polymerase containing$\sigma$$\^$38/ (E$\sigma$$\^$38/) in Escherichia coli, we examined transcription from the stationary-phase promoters, katEP, bo1AP, hdeABP, csgBAP, and mcbP, in vivo and in vitro. Although these pro-moters are preferentially recognized in vivo by E$\sigma$$\^$38/, they are transcribed in vitro by both E$\sigma$$\^$38/ and E$\sigma$$\^$70/ containing the major exponential $\sigma$, $\sigma$$\^$70/. In the presence of high concentrations of glutamate salts, how-ever, oldy E$\sigma$$\^$38/ was able to efficiently transcribe from these promoters, which supports the concept that the promoter selectivity of $\sigma$$\^$38/-containing RNA polymerase is observed only under specific reaction con-ditions. The examination of 6S RNA, which is encoded by the ssr1 gene in vivo, showed that it reduced E$\sigma$$\^$70/ activity during the stationary phase, but this reduction of activity did not result in the elevation of E$\sigma$$\^$38/ activity. Thus, the preferential expression of stationary-phase genes by E$\sigma$$\^$38/ is unlikely the con-sequence of selective inhibition of E$\sigma$$\^$70/ by 6S RNA.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.8
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• pp.1334-1339
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• 2016

In a power grid that has a high wind power penetration, the fast voltage support of a wind power plant (WPP) during the grid fault is required to stabilize the grid voltage. This paper proposes a voltage control scheme of a doubly-fed induction generator (DFIG)-based WPP that can promptly support the voltage of the point of common coupling (PCC) of a WPP during the grid fault. In the proposed scheme, the WPP and DFIG controllers operate in a voltage control mode. The DFIG controller employs two control loops: a maximum voltage dip-dependent reactive current injection loop and a reactive power to voltage loop. The former injects the reactive power in proportion to the maximum voltage dip; the latter injects the reactive power in proportion to the available reactive power capability of a DFIG. The former improves the performance of the conventional voltage control scheme, which uses the latter only, by increasing the reactive power as a function of the maximum voltage dip. The performance of the proposed scheme was investigated for a 100-MW WPP consisting of 20 units of a 5-MW DFIG under various grid fault scenarios using an EMTP-RV simulator. The simulation results indicate that the proposed scheme promptly supports the PCC voltage during the fault under various fault conditions by increasing the reactive current with the maximum voltage dip.

• International Journal of Automotive Technology
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• v.4 no.1
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• pp.47-55
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• 2003

The Center for Transportation Research at the Argonne National Laboratory (ANL) supports the DOE by evaluating advanced automotive technologies in a systems context. ha has developed a unique set of compatible simulation tools and test equipment to perform an integrated systems analysis project from modeling through hardware testing and validation. This project utilized these capabilities to demonstrate the trade-off in fuel economy and Oxides of Nitrogen (NOx) emissions in a so-called ‘pre-transmission’ parallel hybrid powertrain. The powertrain configuration (in simulation and on the dynamometer) consists of a Compression Ignition Direct Ignition (CIDI) engine, a Continuously Variable Transmission (CVT) and an electric drive motor coupled to the CVT input shaft. The trade-off is studied in a simulated environment using PSAT with different controllers (fuzzy logic and rule based) and engine models (neural network and steady state models developed from ANL data).

• ETRI Journal
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• v.25 no.6
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• pp.423-436
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• 2003

This paper describes our design of a contents distribution framework that supports transparent distribution of digital contents on the Internet as well as copyright protection of participants in the contents distribution value chain. Copyright protection must ensure that participants in the distribution channel get the royalties due to them and that purchasers use the contents according to usage rules. It must also prevent illegal draining of digital contents. To design a contents distribution framework satisfying the above requirements, we first present four digital contents distribution models. On the basis of the suggested distribution models, we designed a contract system for distribution of royalties among participants in the contents distribution channel, a license mechanism for enforcement of contents usage to purchasers, and both a packaging mechanism and a secure client system for prevention of illegal draining of digital contents.

• International Journal of Contents
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• v.16 no.2
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• pp.30-40
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• 2020

This study performed GIS and statistical analyses on the location and spatial characteristics of the slum in Daejeon. Spatial data of 648 slum residents in Daejeon were collected and 131 residents among them were surveyed. The results showed the trends of higher rent, lower social exclusion and closer neighboring relations in slum center than the surrounding areas, which could be interpreted as the interrelated multilateral effects of the micro- (housing), meso- (relations), exo- (community) and macro- (government policy) systems. The strong bonds among neighbors and various supports from social service facilities elevated the slum area's rent and diminished residents' social exclusion more than housing conditions (for instance, poor hygiene and low safety). Slum tenants willingly paid a premium for their substandard housings and refused moving to governmentally provided modern housing units. In urban development, administrative authorities need to be cautious about slum uprooting. Much rather an alternative renewal approach is needed which protects the slum's intimate relations while improving its overall living standards.

• The Journal of Information Systems
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• v.19 no.3
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• pp.263-278
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• 2010

Emergency Medical Service(EMS) requires a system that supports the communication between emergency medical technicians (EMT)s and the doctor in the emergency department. Because the rapid triage and on-site treatment of patients need doctor's medical advice. However, a system to assist the doctor assign for medical advice does not exist in Korea. This paper suggests a medical advice support system that focuses on appropriate doctor assign and real-time communication among the ambulance, the Emergency Medical Information Center (EMIC), and the doctor using an agent system. We expect that the system can help to solve the problems affecting prehospital EMS and improve its general quality.

• Journal of the Korean Home Economics Association
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• v.33 no.5
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• pp.13-25
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• 1995

The purpose of this study was to understand the variables affecting the dual role strain and the satisfaction with the life of working mothers, Based on this result, the family policies for the balance between family life and work were proposed. 1) For the family, husband's psychological and behavioral supports were needed to wives as workers. 2) For business, the child care support and services have to be provided for children of both male and female employees. 3) For the government, the policies can be proposed : child care center or support and service in the business, child care program after school hours, insurance policies for child safety, deduction in income taxes corresponding expenditures for child care service.

• Journal of Engineering Education Research
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• v.13 no.5
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• pp.66-71
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• 2010

Recently, engineering work become very important for the leaders of the information society for the future knowledge in the 21st century and the goal of engineering education is to prepare people to practice engineering as a profession and also to spread technological literacy, increase student interest in technical careers through science and math education. The College of Engineering (COE) of Korea Maritime University (KMU) aims to be the center of both IT-related high industrial technology and the industries related to port, shipbuilding and the ocean. Especially COE focuses on the educational principles to contribute to the development of the country and the regional communities by educating specialists that have international competitiveness. With the need to expand international collaboration in terms of engineering work, it is proposed to initiate a new state of the Asian-Pacific body of engineering conference. To the extent possible the basic discussion was made to expose elements and supports as full-scale illustration of the engineering conference. The result is a body that evokes multi agreement and joint declaration among members.