• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2001.09a
• /
• pp.67-74
• /
• 2001

This paper presents the Safe Shutdown Earthquake(SSE) input motion for the seismic design of the Advanced Power Reactor 1400(APR1400). The Design Ground Response Spectra(DGRS) far the SSE is based on the design spectrum specified in regulatory Guide(RG) 1.60 of U.S. Nuclear Regulatory Commission(US NRC), anchored to a Peak Ground Acceleration(PGA) of 0.3g and enriched in the high frequency range. This SSE seismic input motion is to be applied to the seismic analysis as the free-field seismic motion at the ground surface of both the rock and generic soil sites fur APRI1400. The enrichment for APR1400 seismic input motion is performed considering the current US NRC regulations, the seismic hazard studies performed by the Lawrence Livermore National Laboratory (LINL) and Electric Power Research Institute(EPRI) for the Central and Eastern United States nuclear power plant sites, and the seismic input motions used in the design certifications of the three existing U.S. advanced standard plants. It is represented by a set of DGRS and the accompanying Target Power Spectral Density(PSD) Function in both the horizontal and vertical directions.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.5
• /
• pp.804-811
• /
• 2001

In many Gram-negative bacteria, autoinducers, such as N-acyl-L-homoserine lactone(acyl-HSL) and its derivative molecules, mediate the cell-density-dependnet expression of certain operons. The current study identified the autoinducers produced by Burkholderia cepacia G4, a trichloroethylene-degrading lagoon isolate, using TLC bioassays with Agrobacterium tumefaciens NT1(pDCI141E33) and Chromobacterium violaceum CVO26, and a GC-MS analysis. The ${R_f}\;and\;{R_t}$ values and mass spectra were compared with those of synthetic compounds. Based on the analyses, it was confirmed that G4 produces N-hexanoyl (C6)-, N-octanoyl (C8)-, N-decanoyl (C10)-, N-dodecanoyl (C12)-HSL, and an unknown active species. The integration of the GC peak areas exhibited a ratio of C8-HSL:C10-HSL:C12-HSL at 3:17:1 with C6-HSL and C10-HSL production at trace and micromolar levels, respectively, in the culture supernatants. Nutants partially defective in producing acyl-HSLs were also partially defective in the biosynthesis of an antibiotic substance. These results indicate that the autoinducer-dependent gene regulation in G4 is dissimilar to the clinical B. cepacia strains isolated from patients with cystic fibrosis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.05c
• /
• pp.63-66
• /
• 2002

Bi-layer Mo films were deposited on sodalime glass substrates using DC magnetron sputtering. As the gas pressure and power density, the resistivity varied from $1.5{\times}10^{-5}$ to $4.97{\times}10^{-4}{\Omega}{\cdot}cm$. Furthermore, stress direction yielded compressive-to-tensile transition stress curves. The microstructure of the compressive stress films which had poor adhesion consists of tightly packed columns, but of the tensile-stressed films had less dense structure. Under all gas pressure conditions, Mo films exhibited distinctly increasing optical reflection with decreasing gas pressure. The expansion of (110) peak width with the gas pressure meant the worse crystalline growth. Also, The highest efficiency was 15.2% on 0.2 $cm^2$. The fill factor, open circuit voltage and short circuit current were 63 %, 570 m V and 42.6 $mA/cm^2$ respectively.

• Journal of Electrochemical Science and Technology
• /
• v.7 no.2
• /
• pp.179-184
• /
• 2016

The interface between the surface of a cathode material and the electrolyte gives rise to surface reactions such as solid electrolyte interface (SEI) and chemical side reactions. These reactions lead to increased surface resistance and charge transfer resistance. It is consequently necessary to improve the electrochemical characteristics by suppressing these reactions. In order to suppress unnecessary surface reactions, we coated cathode material using polypropylene (PP). The PP coating layer effectively reduced the SEI film that is generated after a 4.3 V initial charging process. By mitigating the formation of the SEI film, the PP-coated Li[(Ni_0.6Co_0.1Mn_0.3)_0.36(Ni_0.80Co_0.15Al0.05)_0.64)]O₂(NCS) electrode provided enhanced transport of Li⁺ ions due to reduced SEI resistance (R_SEI) and charge transfer resistance (R_ct). The initial charge and discharge efficiency of the PP-coated NCS electrode was 96.2 % at a current density of 17 mA/g in a voltage range of 3.0 ~ 4.3 V, whereas the efficiency of the NCS electrode was only 94.7 %. The presence of the protective PP layer on the cathode improved the thermal stability by reducing the generated heat, and this was confirmed via DSC analysis by an increased exothermic peak.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.11a
• /
• pp.57.1-57.1
• /
• 2011

We studied the performance of CdSe nanoparticle in the active layer of organic photovoltaics (OPVs) by changing concentration of the CdSe NPs in the P3HT:PCBM layer. We observed that the absorption peak value gradually increases with the increasing amount of CdSe NPs at 600nm wave length. However, the electrical properties of OPVs correspond less with the tendency of UV/visible result. The highest performance was shown with 10% of CdSe NPs. The device performance decreased after 10% of CdSe NPs, this shows the dependencies of performanc of hybrid solar cells on the CdSe NPs loading amount. The resulting OPVs with 10 % of CdSe NPs show a short circuit current density ($J_{sc}$) of $6.96mA/cm^2$, open circuit voltage ($V_{oc}$) of 0.61V, fill factor (FF) of 0.59, and power conversion efficiency (PCE) of 2.53% under AM 1.5 ($100mW/cm^2$).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.9
• /
• pp.878-882
• /
• 2006

We have fabricated single organic layer devices of the organolanthanide complex, terbium tris-(1-phenyl-3-methyl-4-(tertiarybutyry)pyrazol-5-one)triphenylphosphine oxide [$(tb-PMP)_{3}Tb-(Ph_{3}PO)$] for the investigation of its light emission and electrical conduction properties. The thickness of ($(tb-PMP)_{3}Tb-(Ph_{3}PO)$) layer was varied to 60, 75, 95 nm. Mg and Ca layers were used for the cathode contact. The electrical conduction in the $(tb-PMP)_{3}Tb-(Ph_{3}PO)$ single layer devices was dominated by the injection of electrons into the organic layer from the cathode. A higher current density at much lower voltages can be attained with Ca cathode because of the enhanced electron injection. The device shows very sharp emission at 548 nm. The FWHM of the strongest emission peak was 12 nm.

• Proceedings of the KIEE Conference
• /
• 1997.07d
• /
• pp.1606-1608
• /
• 1997

We have synthesized PPP from benzen by chemical reaction. And then disordered carbon materials were obtained by heating-treating PPP in a nitrogen atmosphere for 1, 4, 8 and 12 hour at $700^{\circ}C$. The carbon prepared by heat treatment showed a broad x-ray diffraction peak around $2{\theta}=20^{\circ}$ having a property of disordered carbon. Carbon electrodes were charged and discharged at a current density of $0.25mA/cm^2$. In the result, PPP-based carbon obtained at $700^{\circ}C$ for 8h showed 605mAh/g of first discharge capacity and had a small hysteresis characteristic.

• Current Optics and Photonics
• /
• v.1 no.4
• /
• pp.358-363
• /
• 2017

In this study, we present a detailed investigation of luminescence properties of a blue light-emitting diode using InGaN/GaN (indium component is 17.43%) multiple quantum wells as the active region grown on patterned sapphire substrate by low-pressure metal-organic chemical vapor deposition (MOCVD). High-resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), Raman scattering (RS) and photoluminescence (PL) measurements are employed to study the crystal quality, the threading dislocation density, surface morphology, residual strain existing in the active region and optical properties. We conclude that the crystalline quality and surface morphology can be greatly improved, the red-shift of peak wavelength is eliminated and the superior blue light LED can be obtained because the residual strain that existed in the active region can be relaxed when the LED is grown on patterned sapphire substrate (PSS). We discuss the mechanisms of growing on PSS to enhance the superior luminescence properties of blue light LED from the viewpoint of residual strain in the active region.

• Korean Journal of Materials Research
• /
• v.24 no.3
• /
• pp.123-128
• /
• 2014

To realize high-performance thin film solar cells, we prepared CIGS by the co-evaporation technique on both sodalime and Corning glass substrates. The structural and efficient properties were investigated by varying the thickness of the Mo:Na layer, where the total thickness of the back contact was fixed at 1${\mu}m$. As a result, when the Mo:Na thickness was 300 nm on soda-lime glass, the measured Na content was 0.28 %, the surface morphology was a plate-like compact structure, and the crystallinity by XRD showed a strong peak of (112) preferential orientation together with relatively intense (220) and (204) peaks as the secondary phases influenced crystal formation. In addition, the substrates on soda-lime glass effected the lowest surface roughness of 2.76 nm and the highest carrier density and short circuit current. Through the optimization of the Mo:Na layer, a solar conversion efficiency of 11.34% was achieved. When using the Corning glass, a rather low conversion efficiency of 9.59% was obtained. To determine the effects of the concentration of sodium and in order to develop a highefficiency solar cells, a very small amount of sodium was added to the soda lime glass substrate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.14 no.9
• /
• pp.731-735
• /
• 2001

S $r_{0.89}$B $i_{2.4}$T $a_2$ $O_{9}$ (SBT) thin films are deposited on Pt-coated electrode(Pt/Ti $O_2$/ $SiO_2$/Si) using RF magnetron sputtering method. In the XRD pattern, the SBT thin films had (105) orientation. As annealing temperature was increased from $600^{\circ}C$ to 85$0^{\circ}C$, the intensities of peak were increased. In the SEM images, Bi-layered perovskite phase was crystallized above $650^{\circ}C$ and rod-like grains grew above 75$0^{\circ}C$. The maximum remanent polarization and the coercive electric field at annealing temperature of 75$0^{\circ}C$ are 11.60$\mu$C/$\textrm{cm}^2$ and 48kV/cm respectively. The dielectric constant and leakage current density at annealing temperature of 75$0^{\circ}C$ are 213 and 1.01x10$^{-8}$ A/$\textrm{cm}^2$, respectively. The fatigue characteristics of SBT thin filmsdid not change up to 10$^{10}$ switching cycles.s.s.