• Rapid Communication in Photoscience
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• v.4 no.2
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• pp.29-30
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• 2015

Since the first report on long-term durable perovskite solar cell in 2012, a surge of interest in perovskite solar cell has been received due to its superb photovoltaic performance exceeding 20%. $MAPbI_3$ ($MA=CH_3NH_3$) perovskite film is able to be prepared simply by solution processesof either sequential two-step or single step procedure. Since $MAPbI_3$ shows balanced charge transport property with micrometer scale charge diffusion length, it can be applied to any kind of junction structures. Mostly studied structure is mesoscopic structure employing mesoporous oxide layer in perovskite film. Photovoltaic performance is primarilyin fluenced by the quality of perovskite film but interfaces are equally important. In this mini review, emergence and evolution of perovskite solar cell are described.

• Proceedings of the KWS Conference
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• 2005.11a
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• pp.150-151
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• 2005

High capacity container carrier has been considered for many decades to transport the more containers at the same time. Therefore, it is required for high capacity container ship to be applied thicker plate to accomodate a mumber of containers compared to that of general container ship. To increase productivity of welding, new welding process should be considered. A representive process for increase of weld productivity is EGW(Electrode Gas Welding) process. Both sides EGW process was evaluated for thicker-plate TMCP Steel. From the test result, it is considered that this process can be applied, showing satisfaction of mechanical properties such as tensile strength and impact property.

• Ceramist
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• v.21 no.2
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• pp.29-37
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• 2018

In order to overcome the problems of existing low-dimensional materials (carbon nanotubes, graphene, transition metal dichalcogenides, etc) researches on new 1D materials have been studied. In the case of $LiMo_3Se_3$ and $Mo_6S_{9-x}I_x$, continuous researches have been carried out for 3D bulk synthesis and atomic scale dispersion. Recently, quantum confinement effect of $LiMo_3Se_3$ and bio-stability of $Mo_6S_{9-x}I_x$ have been proven and various applications have started to be studied. In addition, device application results using new 1D materials such as $Sb_2Se_3$ (optoelectronic devices using the property of effectively reducing exciton decay due to no dangling bond) and $VS_4$ (electrochemical energy storage using the space between 1-D nanostructures) have been reported very importantly. Therefore, it can be claimed that it has reached a very important time to find and synthesize new 1D materials and to report various characteristics not existing.

• Journal of the Korean Applied Science and Technology
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• v.31 no.1
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• pp.151-158
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• 2014

Asphaltenes are generally defined by their solubility when a light alkane, such as n-heptane or n-pentane, is mixed with crude oils or oil sand bitumen. However, this definition is nowadays not enough to understand their behaviors during oil recovery, transport, storage, and even refinery operation. Interestingly, the researches regarding asphaltenes have been vastly presented within last decade. This is because the production of heavy oils is becoming larger and asphaltenes are known to play an important role in the property changes of heavy oils. In this paper, the researches regarding molecular weight, aggregation behavior of asphaltenes are introduced and discussed. It is expected that analytical studies will be appeared continuously in the form of global collaboration in order to describe asphaltene molecules as close as possible based on their origin.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.801-804
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• 2006

Polycarboxylate type superplasticizers(PC) have got widely used for making not only high performance concrete but low grade concrete as well. It is known that fluidity of cement with PC is affected by the characteristics of cement especially sulphate ion concentration and hydration activity. But the characteristics of PC also affect the fluidity. The fluidity of cement mortar with various types of PC was measured and critical dosage(CD) and dispersing ability(DA) was calculated. CD and DA is strongly dependent on the type of PC. And the variation of fluidity on time was affected by the type of PC also. So, it is advisable to investigate the property of PC before production of concrete and adjust it to meet the requirements of concrete depending on the materials, the time of transport and so on.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.1
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• pp.171-180
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• 2012

This study shows that access to urban railway station affects the development of railway station's surrounding zone (RSSZ). For instance, the value of the property in RSSZ is likely to rise on the basis of the before and after the opening of a urban railway. Urban railway system is believed as an important solution to resolve worsening transport problems in metropolitan city. Also, the opening of a urban railway line is expected to affect the change of urban spatial structure, and to have more influence on land price of RSSZ.

• Journal of the Korean institute of surface engineering
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• v.50 no.2
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• pp.55-71
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• 2017

Transparent Conductive Oxide (TCO), especially Indium Tin Oxide (ITO) films are almost prepared by DC magnetron sputtering because of the advantage of obtaining homogeneous large area coatings with high reproducibility. The purpose of this report is describe a detailed investigation of key factors dominating electrical and structural properties of sputtered ITO films. It was confirmed that crystallinity and electrical properties of ITO films were strongly depend on the sputtering pressure and kinetic energy of sputtered particles which are expected to have a close relation with the transport processes between target and substrate. And also, nodule formation on the ITO target was suppressed by both $CaCO_3$ addition and decreasing micro-pore in the target. On the other hand, we focused on the characteristics of amorphous TCO film to use as transparent electrode for various applications. To realize high thermoelectric performance, it was tried to control both high electrical conductivity and low thermal conductivity for the amorphous IZO:Sn films.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.3
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• pp.247-253
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• 2000

We evaluated the electric properties of Bi-2223 jointed tapes processed by both resistive-and superconducting-joint methods. For resistive-joint. filler materials of wood metal Pb/Sn. In and silver paste were used whereas for superconductive-joint lap joint method was used. In the resistive joint tape. critical transport property(CCR) n-value and contact resistance were observed to be in the range of 10-85% 1-8,9. and 0.71x10$\^$-6/-0.13x10$\^$-6/Ω, respectively. depending on their filler materials. Specifically it is believed that the electrical properties of resistive joint tape are significantly related to the resistivity of filler materials. On the other hand the CCR of superconductin joint type was varied 55 to 85% with uniaxial pressure probably due to the irregular microstructure in the transition region.

• Journal of the Korean institute of surface engineering
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• v.34 no.1
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• pp.25-32
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• 2001

$TiB_2$ ceramics were oxidized at 800, 900 and $1000^{\circ}C$ in air for 40 hr, and their oxidation property was investigated using TGA, XRD, SEM and EPMA. The oxidation resistance decreased with an increase in oxidation temperature. The scale was essentially composed of $TiO_2$ only. $B_2$$O_3$ formed during oxidation escaped from the $TiO_2$ oxide scale owing to its high vapor pressure. This made the oxide scale highly porous and thick. The oxidation reaction was mainly governed by the inward transport of oxygen.$ TiO_2$ existing at the outermost scale grew into peculiarly shaped blades, as the reaction progressed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.362-363
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• 2007

The transport property of stabilized amorphous selenium typical of the material used in direct conversion x-ray imaging devices was studied using the moving photo-carrier grating (MPG) technique and time-of-flight (TOF) measurements. For MPG measurement, the electron and hole mobility, and recombination lifetime of a-Se films with arsenic (As) additions have been obtained. For TOF measurement, a laser beam with pulse duration of 5ns and wavelength of 350 nm was illuminated on the surface of a-Se with thickness of $400{\mu}m$.