[en] This study reports on the characteristics and the role as a buffer layer for YBa₂Cu₃O₇-x of the BaTiO_3a thin films deposited on (100) p-Si, (111) InSb and indium tin oxide-coated (ITO) soda lime glass substrates by metalorganic chemical vapor deposition (MOCVD). The as-grown BaTiO₃ films deposited on various substrates at different temperatures below 600 .deg. C had mirror like surfaces without having any indication of pin-holes, which was confirmed by Normarski optical microscopy. The results of the AES measurements of the BaTiO₃ films on (100) Si showed that the films have a stoichiometric composition containing barium, titanium, and oxygen. The ratios of the peak-to-peak intensities of the Ba_textKLL, Ti_textKLL, and O_textKLL peaks of the BaTiO₃ films were similar to those of a standard bulk BaTiO₃ sample. The results of X-ray diffraction (XRD) and the high-resolution cross sectional transmission electron microscopy (XTEM) results suggested as follows : The as-grown film on (100) Si exhibited a highly oriented polycrystal film growth with the amorphous interfacial layer. The BaTiO₃ film deposited on (111) InSb at 300 .deg. C had the peak occurring at 2 θ=31.26 .deg. , which arise from the three-dimensional, partially epitaxial microcrystal at the interface. The films grown on ITO glass at substrate temperature of 400 .deg. C and 550 .deg. C were of an amorphous phase(α-BaTiO₃). Atomic force microscopy (AFM) measurements under ambient conditions showed that the surface morphologies of the as-grown BaTiO₃ film were strongly influenced not only by crystallinity such as amorphism but also by growth characteristics. The plots of capacitance-voltage (C-V) for the BaTiO₃ thin films on (100) Si and (111) InSb substrates were similar to that of the C-V measurements of an ordinary prepared Al/SiO₂/Si diode. The dielectric constants of films on (100) Si and (111) InSb determined from the C-V measurements were approximately 200 and 30, respectively. The interface state density at the BaTiO₃/Si and BaTiO₃/InSb interface determined by the Terman method was approximately as high as 10¹¹ eV cm^-2 at the middle of the Si and InSb energy gap. In addition, the current-voltage (I-V) measurements were performed to investigate possible leakage of an MIS diode using the BaTiO₃ layer as an insulator gate. In the case of the films on ITO glass, dielectric constant and breakdown voltage were 12.9 and up to 2 x 10⁶V/cm, respectively. The plots of dielectric loss (tan δ) and dielectric constant (verepsilon) at room temperature as a function of frequency for the Ag/α-BaTiO₃/ITO showed typical frequency dependence characteristic of the dielectric thin film having a metal-insulator-metal (MIM) structure. The optical band gap (E_g) of the layer deposited at 400 .deg. C determined by the spectrophotometer measurements was approximatley 4.71eV. It is possible to deposit the α-BaTiO₃ thin film on ITO glass at 400 .deg. C not only with good structural characteristics such as surface morphology and interface property but also with adequate optical properties for applications of thin film electroluminescence device (TFELD) deposited by MOCVD. Although the YBa₂Cu₃O₇-x film deposited at 750 .deg. C by the MOCVD had transition temperature point, the as-grown films did not show superconducting behaviors. The as rown BaTiO₃ film on the Si prevents the outdiffusion of Si toward the YBa₃Cu₃O₇-x film, the higher growth temperature promotes chemical reaction of the YBa₂Cu₃O₇-x film and the BaTiO₃ resulting in degradation of superconducting properties. Therefore, lowering the deposition temperature and the deposition of the high quality epitaxial BaTiO₃ buffer layer are necessary to improve the properties of the YBa₂Cu₃O₇-x superconducting film on BaTiO₃/Si substrate

No abstract available

[en] Korea methodology and experience in international cooperation in the field of construction and operation of nuclear power plants as well as Korean views on development and deployment of advanced nuclear nuclear power systems are presented

[en] We report on the characteristics of rapid-thermal-annealed LiNi_1-xCo_xO₂ cathode films for all-solid-state thin film microbatteries (TFBs). Scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy and Auger electron spectroscopy results show that the surface oxide layer formed on the as-deposited LiNi_1-xCo_xO₂ film is completely removed by a rapid thermal annealing process. All-solid-state TFBs consisting of Li/LiPON/LiNi_1-xCo_xO₂/Pt/MgO/Si exhibit stable cyclibility and a high specific discharge capacity of 60.2 μAh/cm² μm. It is concluded that the Li_yNi_1-xCo_xO₂ cathode could represent a promising candidate for a cathode film in TFBs

[en] We present a first-principles study of the quantum conductance of hybrid nanotube systems consisting of single-walled carbon nanotubes (SWCNTs) encapsulating either an isolated single C60 molecule or a chain of C60 molecules (nanotube peapods). The calculations show a rather weak bonding interaction between the fullerenes and the SWCNTs. The conductance of a (10,10) SWCNT with a single C60 molecule is virtually unaffected at the Fermi level, but exhibits quantized resonant reductions at the molecular levels. The nanotube peapod arrangement gives rise to high density of states for the fullerene highest occupied molecular orbital and lowest unoccupied molecular orbital bands

[en] Recently, all‐solid-state batteries (ASSBs) with an inorganic solid electrolyte have attracted significant interest because of their high potential for unique applications in space, deep sea, and radioactive environments. The inorganic solid electrolyte is one of the most fundamental parts since it determines the C rate and self-discharge properties. We prepared a series of ASSBs based on lithium lanthanum tantalum oxide (LLTO) solid-electrolyte thin films with thicknesses of 0, 100, and 200 nm by radio frequency (RF) magnetron sputtering. The microstructure and composition of the LLTO thin films were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The results show that the LLTO thin films have a high ionic conductivity, and they reduce the contact resistance between the cathode and the solid electrolyte, and increase the ion path between the cathode and the bulk electrolyte. Thus, they can be applied to ASSBs as an interlayer between the cathode and the solid electrolyte. - Highlights: • Observed a microcrystalline structure of fabricated LLTO thin films by sputtering • Increased ionic conductivity of the LLTO thin films between cathode and electrolyte • Found high capacity and stability of the ASSB with a 100 nm thick LLTO thin films • Enhanced ion path and reduced contact resistance of LLTO thin films

[en] The control of microstructure, from a compact to a porous TiO₂layer, was investigated for the fabrication of dye-sensitized solar cells (DSSCs) by employing aerosol deposition. A highly compact TiO₂ layer that suppresses electron recombination was grown on fluorine-doped tin oxide electrode by strong impact and the consolidation of sub-micron-size powders. By spraying a mixture powders with different diameters during the aerosol deposition, it was possible to grow a porous TiO₂ layer on the compact layer without the need for binder components. The performance of DSSCs with as-deposited TiO₂layers produced by aerosol deposition was compared with corresponding values for an annealed sample. The effect of the compact layer on the conversion efficiency of DSSCs was also investigated. The conversion efficiency of DSSCs with a compact layer was enhanced by 62% compared to those without a compact layer. - Highlights: • A TiO₂ multi-layer for dye-sensitized solar cell was grown by aerosol deposition. • A highly compact TiO₂ layer was used to suppress electron recombination. • A porous TiO₂ layer was grown using a mixture of 700 nm and 25 nm-diameter powders. • The conversion efficiency was enhanced by 62% after adding a compact TiO₂ layer

[en] An enhanced element-free Galerkin (EFG) method with enhancement functions is proposed to improve the solution accuracy for linear elastic fracture problem. The enhancement functions are added to the conventional EFG approximation for the implicit description of near-tip field. The discontinuity of crack surface is efficiently modeled by introducing a discontinuity function. Essential boundary conditions are enforced with the penalty method and a coupling with finite element. The proposed method models the crack growth implicitly without node operation so that the initial node arrangement is not modified until the end of analysis. Numerical examples for various crack problems show the robustness of the proposed method by examining the stress intensity factor, near-tip stress field and errors

[en] The authors present calculations of NMR chemical shifts in crystalline phases of some representative amino acids such as glycine, alanine, and alanyl-alanine. To get an insight on how different environments affect the chemical shifts, they study the transition from the crystalline phase to completely isolated molecules of glycine. In the crystalline limit, the shifts are dominated by intermolecular hydrogen-bonds. In the molecular limit, however, dipole electric field effects dominate the behavior of the chemical shifts. They show that it is necessary to average the chemical shifts in glycine over geometries. Tensor components are analyzed to get the angle dependent proton chemical shifts, which is a more refined characterization method

[en] The KNGR is to install a Fluidic Device at the bottom of the inner space of the SIT (Safety Injection Tank) to control the flow rate of safety injection coolant from SIT during LBLOCA. During the past two years, a scale model test to obtain the required flow characteristics of the device under the KNGR specific conditions has been performed using the experience and existing facility of AEA Technology (UK) with appropriate modifications. The performance verification test is to be performed this year to obtain optimum characteristics and design data of full size fluidic device. The purpose of the model test was to check the feasibility of developing the device and to produce a generic flow characteristic data. The test was performed in approximately 1/7 scale in terms of flow rate with full height and pressure. This report presents the details of system performance requirements for the device, design procedure for the fluidic device to be used, test facility and test method. The time dependent flow, pressure and Euler number are presented as characteristics curves and the most stable and the most effective flow control characteristic parameters were recommended through the evaluation. A method to predict the size of the fluidic device is presented. And a sizing algorithm, which can be used to conveniently determine the major geometric data of the device for various operating conditions, and a FORTRAN program to produce the prediction of performance curves have been developed. (author). 32 refs., 15 tabs., 47 figs