• Korean Journal of Materials Research
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• v.30 no.11
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• pp.601-608
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• 2020

In this work, Ag₃PO₄/In₂S₃ nanocomposites with low loading of In₂S₃ (5-15 wt %) are fabricated by two step chemical precipitation approach. The microstructure, composition and improved photoelectrochemical properties of the as-prepared composites are studied by X-ray diffraction pattern (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photocurrent density, EIS and amperometric i-t curve analysis. It is found that most of In₂S₃ nanoparticles are deposited on the surfaces of Ag₃PO₄. The as-prepared Ag₃PO₄/In₂S₃ composite (10 wt%) is selected and investigated by SEM and TEM, which exhibits special morphology consisting of lager size substrate (Ag₃PO₄), particles and some nanosheets (In₂S₃). The introduction of In₂S₃ is effective at improving the charge separation and transfer efficiency of Ag₃PO₄/In₂S₃, resulting in an enhancement of photoelectric behavior. The origin of the enhanced photoelectrochemical activity of the In₂S₃-modified Ag₃PO₄ may be due to the improved charge separation, photocurrent stability and oriented electrons transport pathways in environment and energy applications.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2615-2625
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• 2011

Recently in worldwide and Korea domestically, the LRT vehicles are introduced as reputable urban transit system, in a view of energy saving, punctuality and eco-friendly as well as transport efficiency. At first time in Korea, the Busan metro Line 4 was applied with AGT system which is a kind of LRT using the Rubber tired AGT vehicle and developed from 1999 to 2004 in charge of Korean government. Busan selected the AGT system for Metro Line 4 as the solution of traffic jam and networking the intercity. At present, Busan Metro Line 4 has been running since opened at March 30, 2011. The vehicle of Busan metro line 4 is aiming the maximization of LRT vehicle advantage that is the lightness of vehicle size and vehicle weight. So, it did size downed and weight downed by lightened the weight of car frame and bogies and by the compactness of electrical on-board equipments. The study carried out the structure analysis to verify and safety and performance of car body and bogie frame of Busan Metro Line 4 vehicles. In this study, it was analyzed the stress of main load and verified the fatigue strength. And measured the dynamic stress sending to body structure and bogie frame while running on main line and analyzed the fatigue stress. As a result, it verified the safety and life cycle of car body and bogie frame.

• Advances in materials Research
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• v.1 no.2
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• pp.115-128
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• 2012

The structural and electrical properties of $(1-x)Ba(Sm_{1/2}Nb_{1/2})O_3-xBaTiO_3$; ($0{\leq}x{\leq}1$) ceramics were prepared by conventional ceramic technique at $1375^{\circ}C$/7 h in air atmosphere. The crystal symmetry, space group and unit cell dimensions were derived from the X-ray diffraction (XRD) data using FullProf software whereas crystallite size and lattice strain were estimated from Williamson-Hall approach. XRD analysis of the compound indicated the formation of a single-phase cubic structure with the space group Pm m. Dielectric study revealed that the compound $0.75Ba(Sm_{1/2}Nb_{1/2})O_3-0.25BaTiO_3$ is having low and ${\varepsilon}^{\prime}$ and ${\varepsilon}^{{\prime}{\prime}}$ a low $T_{CC}$ (< 5%) in the working temperature range (up to+$100^{\circ}C$) which makes this composition suitable for capacitor application and may be designated as 'Stable Low-K' Class I material as per the specifications of the Electronic Industries Association. The correlated barrier hopping model was employed to successfully explain the mechanism of charge transport in the system. The ac conductivity data were used to evaluate the density of states at Fermi level, minimum hopping length and apparent activation energy of the compounds.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.230-230
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• 2012

Graphene have showed promising performance as electrodes of organic devices such as organic transistors, light-emitting diodes, and photovoltaic solar cells. In particular, among various organic materials of graphene-based organic devices, pentacene has been regarded as one of the promising organic material because of its high mobility, chemical stability. In the bottom-contact device configuration generally used as graphene based pentacene devices, the morphology of the organic semiconductors at the interface between a channel and electrode is crucial to efficient charge transport from the electrode to the channel. For the high quality morphology, understanding of initial stages of pentacene growth is essential. In this study, we investigate self-assembly of pentacene molecules on graphene formed on a 6H-SiC (0001) substrate by scanning tunneling microscopy. At sub-monolayer coverage, adsorption of pentacene molecules on epitaxial graphene is affected by $6{\times}6$ pattern originates from the underlying buffer layer. And the orientation of pentacene in the ordered structure is aligned with the zigzag direction of the edge structure of single layer graphene. As coverage increased, intermolecular interactions become stronger than molecule-substrate interaction. As a result, herringbone structures the consequence of higher intermolecular interaction are observed.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.362-362
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• 2012

Graphene-based materials have been gaining the unprecedented academic and industrial applications, due to the unique charge transport as a new kind of 2-dimensional materials. The applications incorporate electronic devices, nonvolatile memories, batteries, chemical sensors, etc. based on the electrical, mechanical, structural, optical, and chemical features newly reported. The current work employs thermal chemical vapor deposition involving H2 and CH4, in order to synthesize the 2-dimensional graphene materials. The qualitative/quantitative characterizations of the synthesized graphene materials are evaluated using Raman spectroscopy and Hall Measurements, In particular, the effect of processing variables is systematically investigated on the formation of graphene materials through statistical design of experiments. The optimized graphene materials will be attempted towards the potential applications to flat-panel displays.

• Journal of Arbitration Studies
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• v.14 no.2
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• pp.281-300
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• 2004

This paper is about a case on the arbitration of disputes between the parties of charter party. 'B' vessel owner on the original charter party first made a charter party with 'L' cargo owner on the original charter party. Then, 'B' entered into another charter party with 'D' vessel owner, who will actually take charge of carriage of the cargoes which is described on the original charter party. Therefore, 'B' is a carrier of cargoes of 'L' and 'D' is a carrier of cargoes of 'B', according to the contracts. The cargoes of 'B' is cargoes of 'L', by nature. In these circumstances, damages to the cargoes occurred in the transit by the vessel of 'D'. Who should take the responsibility for the damage of cargoes? Who must be liable for those, 'B' or 'D'？. According to the original charter party, 'L' signed 'as Charterers' and 'B' was the counterpart of 'L'. But 'B' signed as 'for and on behalf of 'B',' without 'as Owners'. Tribunal of arbitration award that 'B' should take the responsibility for the damage to the cargoes, because 'B' is the vessel owner. Although 'B' is a contract carrier, 'B' must bear the liability of transport of the cargoes. The counterpart of charterer, 'L' is 'B' who is presumed to be the vessel owner by the original charter party. 'D', actual carrier is not the privy of 'L', cargo owner. This case teach us that signature on the contract is the matter of great importance.

• Current Photovoltaic Research
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• v.6 no.2
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• pp.43-48
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• 2018

The traditional silicon heterojunction solar cells consist of intrinsic amorphous silicon to prevent recombination of the silicon surface and doped amorphous silicon to transport the photo-generated electrons and holes to the electrode. Back contact solar cells with silicon heterojunction exhibit very high open-circuit voltages, but the complexity of the process due to form the emitter and base at the backside must be addressed. In order to solve this problem, the structure, manufacturing method, and new materials enabling the carrier selective contact (CSC) solar cell capable of achieving high efficiency without using a complicated structure have recently been actively developed. CSC solar cells minimize carrier recombination on metal contacts and effectively transfer charge. The CSC structure allows very low levels of recombination current (eg, Jo < 9fA/cm2), thereby achieves high open-circuit voltage and high efficiency. This paper summarizes the core technology of CSC solar cell, which has been spotlighted as the next generation technology, and is aiming to speed up the research and development in this field.

• Applied Microscopy
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• v.47 no.3
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• pp.105-109
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• 2017

The effect of temperature and vanadium metal concentration on the electronic and thermoelectric properties of Si in the diamond cubic structure has been investigated using a combination of density functional theory simulations and the semi classical Boltzmann's theory. The BotzTrap code within the constant relaxation time approximation has been used to obtain the Seebeck coefficient and other transport properties of interest for alloys of the structure $Si_{1-x}V_x$, where x is 0, 0.125, 0.25, 0.375, and 0.5. The thermoelectric properties have been extracted for a temperature range of 300 K to 1,000 K. The general trend with V atom substitution for Si causes the Seeback coefficient to increase and the thermal conductivity to decrease for the various alloys. The optimum values are for $Si_5V_3$ and $Si_4V_4$ alloys for charge carrier concentrations of $10^{21}cm^{-3}$ in the mid temperature range of 500~800 K. This is a very desirable effect for a promising thermoelectric and the figure of merit ZT approaches 0.2 at 600 K for the p-type $Si_5V_3$ alloy.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.432.1-432.1
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• 2016

We demonstrated that the power conversion efficiency (PCE) of bilayer solar cell was significantly enhanced by inserting interfacial layer between the organic bilayer film and the Al electrode. Moreover, the water contact angle shows that the bilayer solar cells suffer from the undesirable surface component which limits the charge transport to the Al electrode. The AFM measurement has revealed that the pre- and post-thermal annealing treatments results in different morphologies of the interfacial layer which is critical for the higher PCE of the bilayer solar cells. Furthermore we have investigated the electrical properties of the bilayer solar cells and obtained insights into the detailed device mechanisms. The transient photovoltage measurements suggests that the significantly enhanced Voc is caused by reducing the recombination at the interface between the organic films and the Al electrode. By inserting the TiO2 layer between the bilayer film and Al electrode, the open circuit voltage (Voc) was increased from 0.37 to 0.66V. Consequently, the power conversion efficiency (PCE) of bilayer solar cells was significantly enhanced from 1.23% to 3.71%. As the results, the TiO2 interfacial layer can be used to form an ohmic contact layer, serveing as a blocking layer to prevent the penetration of the Al, and to reduce the recombination at the interface.

• Journal of the Korea Furniture Society
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• v.20 no.1
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• pp.31-41
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• 2009

In our country, most of the wood resources are imported. We faced a continuous rising of wood price by export country's some conditions and excess rising of transport charge, also a shortage of structural size members. In these situation, recycling or reuse of wood residues and wastes under wood processing industry, building construction and demolition is not a option but a prerequisite. In our country, there is a dearth of data on recycling or reuse of wood residues and wastes, so the investigation on the necessity of recycling or reuse of wood residues and wastes was conducted by using the foreign data and documents. First of all, fields and actual conditions for the domestic wood processing industry were surveyed. Then, kinds and signification of wood residues and wastes were organized. Later, the necessity and the signification of recycling or reuse of wood residues were investigated, and postulations for effective recycling and reuse were suggested. Above all, the necessity of grading standards for reuse or recycling and some important consideration for developing grading standards were emphasized. At last, foreign research tendencies and some applications on recycling or reuse of wood residues and wastes were supplemented.