• Journal of environmental and Sanitary engineering
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• v.10 no.1
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• pp.35-44
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• 1995

The study was carried out to investigate on the response of environmental sanitation problems in action of the volume based waste charge system in Seoul The responses from the 346 persons who dwelled in Seoul was stimulatively answered, this system was considered as a successful on 70.5% of total answers, but little portion(29.4 % ) of those was unknown on the mean of this system. And we knew that this system was need to the communication and education through the press media about this one. After the action of the volume based waste system, the volume of refuse discharged in a day was decreased 30 ∼40% than before. In the problems of environmental sanitation after this system, the number of sanitary insect( cockroach etc ) and rat was decreased, also the production of orders and dust caused by refuse was decreased in comparison with those before. This results were considered that the Separate Collection should be perfectly performed. In response, the regular envelope of refuse was serious problems, the improvement for this one was demanded. The kind of difficult refuse treated was waste rubbers> electric products > furniture> foodstuffs> bottles, cans> papers, pulps etc, and the next proposal for this system should be prepared. Conclusively, the volume based waste charge system should be remarkable system In terms of resources recycling as well as wastes reduction. Above all in order to conform this system the separate collection system should be systematically performed, the next improvable proposal of the detailed methods in this system should be prepared.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.2
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• pp.145-153
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• 2005

An electret fiber with a dipole charge distribution was used to capture charged ultrafine particles in this study. Brownian diffusion and Coulombic force are the dominant collection mechanisms in the electret filtration of charged ultrafine particles. The interaction between Brownian diffusion and Coulombic force for the deposition of ultrafine particles onto a dipolarly charged fiber is studied by solving the convective diffusion equation including Coulombic force as an external force, and the numerical results are compared with the experimental data. As a result, it is shown that there is a negative interaction between Brownian diffusion and Coulombic force, i.e., Coulombic capture efficiency is reduced with decreasing Pe. These results suggest that Brownian diffusion and Coulombic capture efficiency, $\eta$$_{CD}$ is not a simple sum of Brownian diffusion efficiency, $\eta$$_{D}$ and Coulombic capture efficiency, $\eta$$_{C}$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.375-378
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• 2002

There has recently been a great deal of interest in amorphous selenium for application of digital x-ray image sensor. The initial number of the electron-hole induced by interaction a-Se with x-ray photons and the collection efficiency to surface of generated charges are important parameters for x-ray sensitivity of the a-Se. Therefore, in this paper, we analyzed that thickness of a-Se film and electric field is affected on the initial number of electron-hole and the collection efficiency. The experimental value of x-ray induced charge about the various thickness and the electric field is compared with estimated absorbed energy through MCNP 4C code to analyze the mechanism x-ray induced signal of a-Se. The experimental results showed that the electric field depends on initial escape coefficient and the thickness depends on collection coefficient than escape efficient.

• Proceedings of the Materials Research Society of Korea Conference
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• 2002.11a
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• pp.127-127
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• 2002

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.6
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• pp.644-655
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• 2012

As soon as a new air filter is applied to an air purification process, the filter gets loaded with dust particles. Thus, the study on the particle loading characteristics of air filter is very essential in order to understand the real filtration phenomena during filter use. In this study, we investigated the effect of particle and filter charge on the particle loading property of air filter. Charged filter and uncharged filter prepared by discharging the charged filter by isopropyl alcohol were used as test samples, and three types of particle having different charge states were supplied to filters tested. For neutralized particles there was a big difference in areal mass loading rates between charged and uncharged filters due to the very small amount of particle charge, on the other hand the difference was diminished for atomized particle and finally almost vanished for corona charged particles. The pressure drop of filter loaded with corona charged particles was only half of those for neutralized and atomized particles at the same areal mass loading because of the porous structure of particle deposit formed on filter fibers, caused by the space charge effect between particles.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.421-424
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• 2000

In this paper, We presented overview and characteristics of ITS(Intelligent Transport System) DSRC(Dedicated Short Range Communication) system that was introduced to the basic installation for ITS service and proposed system architecture and implementation methods to realize automatic collection of parking charge using DSRC system.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.244-250
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• 2004

The author investigated the causes of local taxes in arrears and based on derived problems, as a person in charge of local tax affairs in the field, examined the efficient collection of unpaid local taxes in three aspects.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.463-463
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• 2014

Dye-sensitized solar cells (DSSCs) have generated a strong interest in the development of solid-state devices owing to their low cost and simple preparation procedures. Effort has been devoted to the study of electrolytes that allow light-to-electrical power conversion for DSSC applications. Several attempts have been made to substitute the liquid electrolyte in the original solar cells by using (2,2',7,7'-tetrakis (N,N-di-p-methoxyphenylamine)-9-9'-spirobi-fluorene (spiro-OMeTAD) that act as hole conductor [1]. Although efficiencies above 3% have been reached by several groups, here the major challenging is limited photoelectrode thickness ($2{\mu}m$), which is very low due to electron diffusion length (Ln) for spiro-OMeTAD ($4.4{\mu}m$) [2]. In principle, the $TiO_2$ layer can be thicker than had been thought previously. This has important implications for the design of high-efficiency solid-state DSSCs. In the present study, we have fabricated 3-D Transparent Conducting Oxide (TCO) by growing tin-doped indium oxide (ITO) nanowire (NWs) arrays via a vapor transport method [3] and mesoporous $TiO_2$ nanoparticle (NP)-based photoelectrodes were prepared using doctor blade method. Finally optimized light-harvesting solid-state DSSCs is made using 3-D TCO where electron life time is controlled the recombination rate through fast charge collection and also ITO NWs length can be controlled in the range of over $2{\mu}m$ and has been characterized using field emission scanning electron microscopy (FE-SEM). Structural analyses by high-resolution transmission electron microscopy (HRTEM) and X-Ray diffraction (XRD) results reveal that the ITO NWs formed single crystal oriented [100] direction. Also to compare the charge collection properties of conventional NPs based solid-state DSSCs with ITO NWs based solid-state DSSCs, we have studied intensity modulated photovoltage spectroscopy (IMVS), intensity modulated photocurrent spectroscopy (IMPS) and transient open circuit voltages. As a result, above $4{\mu}m$ thick ITO NWs based photoelectrodes with Z907 dye shown the best performing device, exhibiting a short-circuit current density of 7.21 mA cm-2 under simulated solar emission of 100 mW cm-2 associated with an overall power conversion efficiency of 2.80 %. Finally, we achieved the efficiency of 7.5% by applying a CH3NH3PbI3 perovskite sensitizer.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.3
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• pp.243-254
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• 1996

The main purpose of this study is to investigate the collection efficiency characteristics of a cylindrical ESP. To do that, it is necessary to analyze the electric field, gas flow field, and mechanism of particle movement by numerical simulation based on EHD model. For a gas flow field, Navier-Stokes equation involving the electric source term was solved by SIMPLE algorithm. In case of the electric field, the current continuity and electric field equations were solved by S.O.R. method. The analysis of particle movement was performed on the basis of PSI-CELL model from the Lagrangian viewpoint. The results showed that the influence on the gas flow field by the electric field is almost negligible in a cylindrical ESP. The particle drift velocity $V_P$ toward the collection surface is increased continuously by the electrostatic force due to the rise of particle charge as the particle is moving to the flow direction and the particle size becomes larger. The collection efficiency is to quitely higher with the increase of applied voltage for the same particle size, while becomes smaller as the inlet velocity is increased.

• Journal of Korean Library and Information Science Society
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• v.46 no.4
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• pp.227-244
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• 2015

The study aims at identifying professional competencies of collection development librarians in academic libraries. For this, the study collected data through qualitative interviews with 8 librarians who are in charge of collection development programs in four-year university libraries. As a result, the professional competency components emerging from interviews were divided into three parts; knowledge in library and information science, knowledge in subject field, and professionalism. Detailed components of three parts of professional competency were divided into 13 sub-categories, with 37 meanings. It is expected that the study as an exploratory research may provide further research to design educational and training programs for collection development librarians with basic data.