• Current Photovoltaic Research
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• v.9 no.1
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• pp.1-5
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• 2021

The properties of the electron transport layer (ETL) have a great effect on perovskite solar cell performance. Depositing conformal SnO2 ETL on bottom textured silicon cells is essential to increase current density in terms of the silicon-perovskite tandem solar cells. In the recent study, the SnO2 electron transport layer deposited by the sputtering method showed an efficiency of 19.8%. Also, an electron transport layer with a sputtered TiO2 electron transport layer in a 4-terminal tandem solar cell has been reported. In this study, we synthesized SnOx ETL with a various sputtering power range of 30-60W by Radio-frequency (RF)-magnetron sputtering. The properties of SnOx thin film were characterized using ellipsometer, UV-vis spectrometer, and IV measurement. With a sputtering power of 50W, the solar cell showed the highest efficiency of 13.3%, because of the highest fill factor by the conductivity of SnOx film.

• Journal of the Korea Society of Computer and Information
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• v.14 no.9
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• pp.179-187
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• 2009

The national boundary's meanings turn to weak according to advent of Global enterprises. The place for design a product and marketing are separated to actual market. R&D is to the area where the knowledge activity is well, and low skilful product assembling is to the place the low wage is acceptable. It shows that the importance of net work structure. From early 90's, production system is diversified to markets where with the consumer as the central as multifarious items and creation new demands through consumer's participation into manufacturing process. This phenomenon show that logistics structures adapt to demand of technical variation, and the development of e-business with VAN(:value added network) and EDI(:Electronic data interchange) prove it. This study tried to analyze utilitarian assay about systems those land, sea, air logistics through documents research, and this study also present the direction of logistics system of airline company and goal of development on the based to the model of domestic airline company accordingly.

• Korea Trade Review
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• v.41 no.1
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• pp.159-186
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• 2016

This study analyzes the degree of dependency and comparative advantage of each country for intermediate goods trade in East Asia, which predicts the comparative advantage of the intermediate goods trade and fragmentation in East Asia when the FTA arrangement in East Asia is implemented. The results are as follows. First, the share of intra-regional trade in the intermediate goods in East Asia has increased over time, implying the deepening of interdependency in intermediate goods trade within the East Asia. Second, Korea is a net exporter in intermediate goods trade for China and ASEAN, whereas it is a net importer for Japan. Japan is a high net exporter for all East Asia, while China is a net importer for Korea, Japan and ASEAN. If FTA arrangement in East Asia is implemented, Japan and Korea will be key suppliers of the intermediate goods for East Asia, while China and ASEAN will play a role of the manufacturing factory through the import of intermediate goods. Third, Korea has a comparative advantage in intermediate trade of electric and electronics and transport vehicle industry in East Asia. Japan has a comparative advantage in all of electric and electronics, transport vehicle, precision instrument, general machinery industry, whereas China has a comparative advantage only in electric and electronics intermediate trade in East Asia. The intra-industry trade of the intermediate goods in precision instrument, general machinery industry is expected to grow among Korea, Japan and China.

• Korean Journal of Materials Research
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• v.33 no.11
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• pp.475-481
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• 2023

Recently, the electron transport layer (ETL) has become one of the key components for high-performance perovskite solar cell (PSC). This study is motivated by the nonreproducible performance of ETL made of spin coated SnO₂ applied to a PSC. We made a comparative study between tin oxide deposited by atomic layer deposition (ALD) or spin coating to be used as an ETL in N-I-P PSC. 15 nm-thick Tin oxide thin films were deposited by ALD using tetrakisdimethylanmiotin (TDMASn) and using reactant ozone at 120 ℃. PSC using ALD SnO₂ as ETL showed a maximum efficiency of 18.97 %, and PSC using spin coated SnO₂ showed a maximum efficiency of 18.46 %. This is because the short circuit current (Jsc) of PSC using the ALD SnO₂ layer was 0.75 mA/cm² higher than that of the spin coated SnO₂. This result can be attributed to the fact that the electron transfer distance from the perovskite is constant due to the thickness uniformity of ALD SnO₂. Therefore ALD SnO₂ is a candidate as a ETL for use in PSC vacuum deposition.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.8
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• pp.851-860
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• 2015

Transport Social Overhead Capital refers to public utilities necessary for a nation's basic economic activities, and is divided into roads, railway, subway, ports and so on. It is important to be able to provide these SOC in the right place at the right time to enhance productivity and competitiveness of a nation. In this study, correlation and factor analysis on countries' socioeconomic and transport indicators were performed in order to understand the need for expansion of SOCs including railway, and to identify the impact they have on national competitiveness(productivity). As a result, GDP showed high correlativity(0.59~0.99) with factors such as population, land area, extension of available railroad, and road extension. Specifically, through the analysis of Russia's urban transport system and comparison between socioeconomic indices and SOCs of OECD countries, it was examined that how increasing transport infrastructure investments could enhance national competitiveness. In conclusion, opening new Light Rail greatly affects the growth of GDP followed by the increasing extension of available railroad. Furthermore, if available railroad extension is increased by 10 % from 2014, assuming high speed tram is opened, GDP will likely increase by 21.6%.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.2
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• pp.23-28
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• 2008

To improve the external quantum efficiency by means of the optimization of the polymer light emitting diodes(PLEDs) structure, the PLED with ITO/PEDOT:PSS/(PFO)/PFO:MEH-PPV/LiF/Al structure were fabricated and investigated the electrical and optical properties for the prepared devices. ITO(indium tin oxide) and PEDOT:PSS [poly (3,4-ethylenedioxythiophene): poly(styrene sulfolnate)] were used as transparent anode film and hole transport materials, respectively. PFO[poly(9,9-dioctylfluorene)] and MEHPPV[poly(2-methoxy-5(2-ethylhe xoxy)-1,4-phenylenevinyle)] were used as the light emitting host and dopant materials. The doping concentration of MEH-PPV was 9wt% with thickness of about $400{\AA}$. We investigated the dependence of the PFO thickness ranging from $200{\AA}$ to $300{\AA}$ on the electrical, optical properties of PLEDs. Among prepared PLED devices with different PFO thicknesses, the highest value of the luminance was obtained for the PLED device with $250{\AA}$ in thickness. As a result, the current density and luminance ware found to be about $400mA/cm^2$ and $1500cd/m^2$ at 13V, respectively. In addition, the luminance and current efficiency of PLED device with double emitting layer (PFO/PFO:MEH-PPV) were improved about 3 times compared with the one with single emitting layer (PFO:MEH-PPV).

• Journal of the Microelectronics and Packaging Society
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• v.13 no.4
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• pp.51-56
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• 2006

Polymer light emitting diodes (PLEDs) with ITO/EDOT:PSS/PVK/PFO-poss/LiF/Al structures were prepared by the spin coating method on ITO(indium tin oxide)/glass substrates. PFO-poss[Poly(9,9-dioctylfluorenyl-2,7-diyl) end capped with poss] was used as light emitting polymer. PVK[poly(N-vinyl carbazole)] and PEDOT:PSS [poly(3,4-ethylenedioxythiophene):poly(styrene sulfolnate)] polymers were used as the hole injection and transport materials. The effect of PFO-poss concentration and the heating temperatures on the electrical and optical properties of the devices were investigated. At the same concentration of PFO-poss solution, the current density and luminance of PLED device tend to increase as the annealing temperature increase from $100^{\circ}C$ to $200^{\circ}C$. The maximum luminance was found to be about 958 cd/m2 at 13V for the PLED device with 1.0 wt% PFO-poss at the annealing temperature of $200^{\circ}C$. In addition, the PLED device showed bluish white emission through the strong greenish peak with 523 nm in wavelength. As the concentration of PFO-poss increase from 0.5 wt% to 1.0 wt% and temperature of PLEDs increase from $100^{\circ}C$ to $200^{\circ}C$, the emission color tend to be shifted from blue with (x, y) = (0.17,0.14) to bluish white with (x, y) : (0.29,0.41) in CIE color coordinate.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.2 s.35
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• pp.155-159
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• 2005

In this report, Polymer light emitting diodes (PLEDs) with an ITO/PEDOT:PSS/MEH-PPV/Al structure were prepared by spin coating method on the glass substrate patterned ITO (indium tin oxide), using PEDOT:PSS(poly(3,4=ethylenedioxythiophene):poly(styrene sulfolnate)) as the hole transfer material and MEH-PPV(poly(2-methoxy-5-(2-ethyhexoxy)-1,4-phenylenvinylene)) having a different concentration (0.1, 0.3, 0.5, 0.7, 0.9, 1.5 wt$\%$) as the emitting material. The electrical and optical properties of the prepared PLED samples were investigated. The good electrical and optical properties were observed for the PLED samples with a MEH-PPV concentration ranging from 0.5 to $0.9 wt\%$. However, the current and luminance values for PLED sample with $1.5 wt\%$ of MEH-PPV decreased greatly. The maximum luminance and light efficiency for the PLEDs with concentration of $0.5 wt\%$ MEH-PPV were $409 cd/m^2$ and 4.90 Im/W at 9 V, respectively. The emission spectrums were found to be $560{\~}585 nm$ in wavelength showing orange color.

• Applied Microscopy
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• v.29 no.2
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• pp.241-253
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• 1999

Fertilization pattern of north temperate bats is known to be unique for their sperm storage in the female reproductive tract during hibernation (e.g. Korean greater horseshoe bats). They copulate in fall but their ejaculated spermatozoa survive until the next spring. In another words they can persist to survive during long hibernation under the cold condition $(8\sim13^{\circ}C)$ and are to be fertilized with the ovum ovulated in the next spring, so called delayed fertilization. The present study was designed to observe morphological and functional changes of spermatozoa plasma membrane of the bats, hamsters which are hibernators, and mice which are non-hibernators in the room and the cold (bat-hibernation) temperatures and to confirm influence of the temperature on spermatozoa; survival rate, acrosome reaction rate, protein distribution, $Na^+-K^+-ATPase$ activities and scanning electron microscopic histochemistry. Based on the experimental results obtained in the present study, there were no significant morphological and functional differences in the spermatozoa plasma membrane in both the room and cold (bat-hibernation) temperatures and such an absence of difference suggests that the spermatozoa plasma membrane might play a pertinent role as a protector for consistent fertilization during and after hibernation.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.4
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• pp.595-606
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• 2022

Korea has the characteristics of traditional power system such as large-scale power generation and large-scale power transmission systems, including 20 GW large-scale power generation complexes in several regions with unit generator capacity exceeding 1.4 GW, 2-3 ultra-high-voltage transmission lines that transport power from large-scale power generation complexes, and 6 ultra-high-voltage transmission lines that transport power from non-metropolitan areas to the metropolitan area. Due to the characteristics of the power system, the penetration level for renewable energy is low, but due to frequency stability issue, some generators are reducing the output of generators. In the future, the issue of maintaining the stability of the power system is expected to emerge as the most important issue in accordance with the policy of expanding renewable energy. When non-inertial inverter-based renewable energy, such as solar and wind power, surges rapidly, the means to improve the power system stability in an independent system is to install a natural inertial resource synchronous condenser (SC) and a virtual inertial resource BESS in the system. In this study, we analyzed the effect of renewable energy on power system stability and the BESS effect to maintain the minimum frequency through a power system simulation. It was confirmed that the BESS effect according to the power generation constraint capacity reached a maximum of 122.81 %.