• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.76-76
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• 2011

Polymer-fullerene based bulk heterojunction (BHJ) solar cells can be fabricated in large area using low-cost roll-to-roll manufacturing methods. However, because of the low mobility of the BHJ materials, there is competition between the sweep-out of the photogenerated carriers by the built-in potential and recombination within the thin BHJ film [12-15]. Useful film thicknesses are limited by recombination. Thus, there is a need to increase the absorption by the BHJ film without increasing film thickness. Metal nanoparticles exhibit localized surface plasmon resonances (LSPR) which couple strongly to the incident light. In addition, relatively large metallic nanoparticles can reflect and scatter the light and thereby increase the optical path length within the BHJ film. Thus, the addition of metal nanoparticles into BHJ films offers the possibility of enhanced absorption and correspondingly enhanced photo-generation of mobile carriers. In this work, we have demonstrated several positive effects of shape controlled Au and Ag nanoparticles in organic P3HT/PC70BM, PCDTBT/PC70BM, Si-PCPDTBT/PC70BM BHJ-based PV devices. The use of an optimized concentration of Au and Ag nanomaterials in the BHJ film increases Jsc, FF, and the IPCE. These improvements result from a combination of enhanced light absorption caused by the light scattering of the nanomaterials in an active layer. Some of the metals induce the plasmon light concentration at specific wavelength. Moreover, improved charge transport results in low series resistance.

• Korean Journal of Materials Research
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• v.9 no.9
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• pp.865-871
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• 1999

Effect of sintering condition in mechanical properties of ZrSiO\ulcorner shell molds was investigated. Number of microcrack in primary layer of the mold was maximized after preheating at $1000^{\circ}C$ for 1.5 hours. Yield strength and specific surface area of the mold were inversely proportion to sintering temperature and time. After hot deformation test at $1500^{\circ}C$ for 4 hours, molds were deformed opposite to the loading direction and backup layers were cracked along the interface between stucco and zircon slurry. Reverse deformation of the molds during hot deformation test was considered to be resulted from the difference of thermal expansion coefficient between alumina stucco and zircon slurry in primary coat, and size difference between zircon stucco and zircon slurry in backup coat.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.1
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• pp.167-174
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• 2009

A Tile Map Service is a regular map service that has been enhanced to serve maps very quickly using a cache of static images. The map cache is a directory that contains image tiles of a map extent at specific scale levels. Returning a tile from the cache takes the server much less time than drawing the map image on demand. Use of a Tile Map Service can dramatically improve the time that clients take to display complex base-maps. Using Tile Map Services thus eliminate the need to trade quality for performance. This study provides a way to construct Tile Map Service System using Open Source GIS. We used GDAL(Geospatial Data Abstraction Library) which is one of the Open Source GIS Softwares to make Tile Map Image and OpenLayers to publish Web Page. Moreover, We conducted a performance test on Tile Map System and Dynamic Map System and evaluated the results of it. As a result, the proposed method makes it easier to construct high performance Tile Map Service using Open Source GIS without commercial products.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.94-98
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• 1982

To understand the growth pattern of ginseng plant under shading, the vertical distribution of leaf area, leaf area index (LAI) and specific leaf weight (SLW) and changes in light intensity as affected by planting position were investigated in 3 to 5 years old ginseng plant populations. Light intensity was vertically lowest at about 10cm above the ground and became low at the rear planting position in 3-year-old population. When culturing bed (96cm in width) were divided into three parts at intervals of 32cm from front to rear, the leaf area in 3-year-old population was largest in middle 1/3 part of planting bed. Light intensity affected the SLW positively, but LAI showed no distinct difference among planting positions. The light environment of 4-year-old population was worse than that of 3-year-old population and leaf area and LAI differed greatly among planting positions. In 5-year-old population, leaf dry weight and leaf area of furrow part (that is, the amount of leaves protruded from the plants which were planted in 1st, 2nd or 3rd lines into the furrow) increased. The dry weights of leaves and stem increased considerably as plant became aged, and were distributed mainly in upper layer.

• Journal of the Society of Disaster Information
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• v.11 no.2
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• pp.235-243
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• 2015

The methods to improve the protection and explosion-proof performance of concrete structures include the backside reinforcement or concrete material property improvement and the addition of structural members or supports to increase the resistance performance, but they are inefficient in terms of economics and structural characteristics. This study is about the basic study on the fiber composite panel cover, and the nano-composite material and adhesive as the filler, to maximize the specific performance of each layer and the protection and explosion-proof performance as the composite panel component by improving the tensile strength, light weight, adhesion and fire-proof performances. The fiber composite panel cover (aramid-polyester ratios of 6:4 and 6.5:3.5) had a 2,348 MPa maximum tensile strength and a 1.8% maximum elongation. The filler that contained the nano-composite material and adhesive had a 4 MPa maximum tensile shear adhesive strength. In addition, the nano-composite filler was 30% lighter than the normal portland cement

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.481-485
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• 1998

Hydrated aluminum sulfate, an inorganic polymer, was synthesized from kaolin in $H_2SO_4$ solution using microwave energy. The maximum rates of alumina extracted from calcined kaolin were 72.8% in a conventional process ($80^{\circ}C$, 1M, and 180min) and 99.9% in a microwave process ($90^{\circ}C$, 1M, and 60 min). Compared with the conventional one, the hydrated aluminum sulfate synthesized under the microwave process had layer structure consisting of plate-shaped large grains. After synthesis and then calcination at $1100^{\circ}C$, both products on conventional and microwave processes were ${\gamma}-Al_2O_3$ with agglomerated powders of spherical shape. The specific area of the products in conventional and microwave processes were 113.5 and $106.6m^2/g$, and their average grain sizes were 46.5 an $26.3{\mu}m$, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3B
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• pp.493-502
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• 2010

In this paper we propose a scalable sensor network system that makes mesh network among the sink nodes to solve the scalability problem of existing sensor network which is caused by multi-hop networking between the sensor nodes. In the proposed system, the sink nodes have the wireless networking ability to communicate with another sink nodes in mesh fashion, and with the monitoring nodes which is located in the local area or internet area. Especially, the system includes L4(Application Layer) routing mechanism that provides subscribe/publish service to serve selective transmission of sensor data to the specific monitoring nodes. The collected sensor data is transmitted to the monitoring nodes when the sensor data is matched with the monitoring node's interesting value.

• Polymer(Korea)
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• v.37 no.2
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• pp.218-224
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• 2013

Graphene oxide (GO) was prepared by the Hummers and Offeman method from graphite. Two different types of functionalized graphene sheets (FGSs) were synthesized by using GO. Hexamethylamine (HDA) substituted vertically to the graphene sheet (Ver-HDA-GS) was synthesized from HDA and epoxy group in GSs. Whereas, horizontally substituted hexadecanol (HDO) to the GS(Hor-HDO-GS) was synthesized from HDO and alcohol groups via reduced GO (RGO), respectively. The structures of the GO, RGO, Ver-HDA-GS, and Hor-HDO-GS were identified by Fourier transform infrared (FTIR). In addition, we examined the thermal stability and morphology. Atomic force microscope (AFM) disclosed that Ver-HDA-GS consisted of one- or two-layer graphene regions. However, the Ver-HDA-GS layers showed average thickness of 1.76 nm. The thermal stabilities of the FGSs were better than those of the GO and RGO. The Ver- HDA-GS was well dispersed in common solvents such as dimethyl sulfoxide (DMSO), toluene, chloroform, and decalin.

• Geophysics and Geophysical Exploration
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• v.12 no.1
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• pp.8-16
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• 2009

The holistic inversion approach for frequency domain airborne electromagnetic data has previously been employed to simultaneously calibrate, process and invert raw frequency-domain data where prior information was available. Analternative formulation has been developed, which is suitable in the case where explicit prior information is not available. It incorporates: a multi-layer vertically-smooth conductivity model; a simplified bias parameterisation; horizontal smoothing with respect to elevation; and cluster computer parallelisation. Without using any prior data, an inversion of 8.0 million data for 3.4 million parameters yields results that are consistent with independently derived calibration parameters, downhole logs and groundwater elevation data. We conclude that the success of the holistic inversion method is not dependent on a sophisticated conceptual model or the direct inclusion of survey-area specific prior information. In addition, acquisition costs could potentially be reduced by employing the holistic approach which largely eliminates the need for high altitude zero-level measurements.

• Korean Journal of Veterinary Service
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• v.34 no.2
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• pp.139-148
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• 2011

Avian reovirus (ARV) and fowl adenovirus (FAdV) were evaluated for pathogenicity in specific pathogen free (SPF) chickens. ARV was isolated from the broilers with history of malabsorption syndrome (MAS). FAdV was isolated from the layer breeders with inclusion body hepatitis and hydropericardium syndrome. Total 6 inoculated groups including 1 un-inoculated group were organized and inoculated with the ARV and/or FAdV by oral route. The minimal pathological lesions and lower viral gene detection rates were present in the ARV inoculated groups compared to those of FAdV or ARV/FAdV inoculated groups. Common gross lesions in the ARV inoculated group were distended intestine with foamy contents and in the FAdV group there were foamy cecal contents and hydropericardium among the evaluation methods such as gross and histological lesion, viral gene detection, body weight and serum chemistry, histopathological lesion score was reliable especially in the liver lesions such as hepatic necrosis and lymphocytic infiltration. However, we did not success to evaluate the synergetic effect of mixed infection of ARV and FAdV in this study. Therefore, we need further study to reproduce malabsorption syndrome of ARV infection using different viral agent such as rotavirus and using different dose of virus.