전자빔 물리증착을 이용한 고체 산화물 연료전지의 제조 : I. YSZ 박막 전해질의 제조

Unique Ligand Exchange Dynamics of Metal–Organic Polyhedra for Vitrimer-like Gas Separation Membranes

Evaluation of basic sites of ZIFs metal organic frameworks in the Knoevenagel condensation reaction

The study of ohmic contacts to wide band-gap semiconductors proves that when metal/semiconductor contacts are deposited, they commonly result in rectifying Schottky contacts which barrier height inhibits current flow across the metal/semiconductor interface. There are four primary variables which control the Schottky barrier height at metal/semiconductor interfaces: the work function фm of the metal; the crystalline or amorphous structure at the metal-semiconductor interface; the diffusion of metal atoms across the interface into the semiconductor; and, the outermost electronic configuration of the metal atoms. Otherwise, there are several constants and properties characterising the wide band-gap semiconductors which postulate the specific approach used for formation of ohmic properties of the metal/semiconductor interface: the high electron affinity, the wide forbidden zone, and low diffusion coefficient of the most metals. Consequently, it is almost impossible to form ohmic properties, relying only to the choice of a metal with suitable work function and metal diffusion into the semiconductor during annealing. Therefore in the case of ohmic contacts to wide band-gap semiconductors metallization schemes have been chosen so as to form intermediate layer at the interface, which could decrease the barrier height and/or narrow the depletion layer at the semiconductor interface. In these cases, heat treatment results interfacial compounds, such as metal/compound/ semiconductor contacts. In these contacts, the metal/semiconductor interface is eliminated and replaced by new interfaces, а metal/compound and а compound/semiconductor interface. The resulting barrier height фB is not longer dependent on the surface properties of the semiconductor or metal work function. Instead, it depends upon the difference in electron affinity and work function between the metal/compound and compound/ semiconductor. As а result, contacts can be reproducibly formed with а predictable фB. In the case of Ni-based and Pd-based contacts to SiC such compound is nickel silicide and palladium silicide, respectively. On the basis of XPS data the following mechanism of chemical reactions occurring during the formation of ohmic properties may be proposed. In the case of Ni/SiC the contact formation is initiated by the dissociation of SiC surface, due to the strong reactivity of Ni at 950 0C. The nickel atoms at the interface interact with a part of dissociated Si atoms and Ni2Si is formed. Simultaneously, at the interface nickel atoms diffuse through the mixed Ni2Si+C layer towards the SiC. Thus, the supply of Ni atoms at the SiC interface continues and the above reactions are repeated to the complete consumption of the deposited nickel layer. Carbon accumulates, both at the interface and in the contact layer. The presence of carbon in the contact layer and at the interface could become a potential source of contact

11 - Dielectric Polymer Materials with High Thermal Stability

Porosity graded anode substrates for solid oxide fuel cells are considered to optimise the gas transport through the substrate by maintaining a high electrochemical activity for fuel oxidation at the anode/solid electrolyte interface. In this work, the fabrication of porosity graded anode substrates, made from nickel oxide and yttria‐modified zirconia and produced by dry uni‐axial pressing, are described. Using carbon as pore formers and adjusting the particle size distribution in the ceramic NiO‐YSZ masses, samples with gradually changing porosity are built up. The sintering behaviour of the individual layers is analysed and partly adjusted so the multi‐layer support can be co‐fired together with the YSZ electrolyte layer. In the oxidized state, four‐layer, porosity graded anode supported half‐cells with a dense YSZ electrolyte are demonstrated.

We present that fabricating ferroelectric thin film capacitor on electrodes of the X-ray detector to make AC-coupled CdTe X-ray imager. In order to determine the capacitance required for the coupling capacitor, radiation spectrum is measured by using some coupling capacitor have different capacitance. As a result, it was found that the more the capacitance is large, we can get correct radiation spectrum. Because small capacitor with large capacitance is required, BaTiO3 is selected as a high dielectric constant material. We fabricated a ferroelectric thin film capacitor with an area of about 48 μm2 and a thickness of about 100 nm by sputtering. As a result of measurement, the capacitance is about 880 pF, and the tendency of variation of dielectric constant with frequency corresponded with past paper. Although the dielectric constant was significantly smaller than the BaTiO3 film in the papers. We considered that the main issue is quality of BaTiO3 film. Quality of film is increased by depositing under high substrate temperature. Performance of CdTe as a radiation detector is deteriorated by high temperature. Therefore, we need to consider the way to deposit BaTiO3 on CdTe at low substrate temperature.

Improving the thermal stability of diamond and other superhard materials has great significance in various applications. Here, we report the synthesis and characterization of bulk diamond–cBN–B4C–Si composites sintered at high pressure and high temperature (HPHT, 5.2 GPa, 1620–1680 K for 3–5 min). The results show that the diamond, cBN, B4C, BxSiC, SiO2 and amorphous carbon or a little surplus Si are present in the sintered samples. The onset oxidation temperature of 1673 K in the as-synthesized sample is much higher than that of diamond, cBN, and B4C. The high thermal stability is ascribed to the covalent bonds of B–C, C–N, and the solid-solution of BxSiC formed during the sintering process. The results obtained in this work may be useful in preparing superhard materials with high thermal stability.

Ultra-low hysteresis electrostrictive strain with high thermal stability in Bi(Li0.5Nb0.5)O3-modified BaTiO3 lead-free ferroelectrics

High thermal stability and tunable magnetic exchange interaction (MEI) in SmCo materials have been the critical problem in applications to magnetic recording media and nanocomposite permanent magnets. We constructed SmCo films with a high thermal stability and tunable MEI by controlling the phase transformation through properly increasing the Sm concentration (20.5–37.7 at.%) and controlling the annealing process. Microstructure studies show that the SmCo5 phases ensure that the film has a high thermal stability. Moreover, we manipulated the MEI in the film with non-magnetic precipitated SmCo2 particles in the vicinity of SmCo5 particles. These results provide a novel way to tune the MEI in SmCo materials while maintaining a high thermal stability.

Precursor-derived SiHfBCN ceramics with ultrahigh temperature stability: Facile preparation, phase evolution behavior, and mechanism of ultrahigh temperature thermal stability

High temperature stability and optical properties investigation of a novel ITO-Therminol 66 nanofluid for spectral splitting PV/T systems

We report the discovery of a rule-breaking two-dimensional aluminum boride (AlB6-ptAl-array) nanosheet with a planar tetracoordinate aluminum (ptAl) array in a tetragonal lattice by comprehensive crystal structure search, first-principles calculations, and molecular dynamics simulations. It is a brand new 2D material with a unique motif, high stability, and exotic properties. These anti-van't Hoff/Le Bel ptAl-arrays are arranged in a highly ordered way and connected by two sheets of boron rhomboidal strips above and below the array. The regular alignment and strong bonding between the constituents of this material lead to very strong mechanical strength (in-plane Young's modulus Y x = 379, Y y = 437 N/m, much larger than that of graphene, Y = 340 N/m) and high thermal stability (the framework survived simulated annealing at 2080 K for 10 ps). Additionally, electronic structure calculations indicate that it is a rare new material with triple Dirac cones, Dirac-like fermions, and node-loop features. Remarkably, this material is predicted to be a 2D phonon-mediated superconductor with Tc = 4.7 K, higher than the boiling point of liquid helium (4.2 K). Surprisingly, the Tc can be greatly enhanced up to 30 K by applying tensile strain at 12%. This is much higher than the temperature of liquid hydrogen (20.3 K). These outstanding properties may pave the way for potential applications of an AlB6-ptAl-array in nanoelectronics and nanomechanics. This work opens up a new branch of two-dimensional aluminum boride materials for exploration. The present study also opens a field of two-dimensional arrays of anti-van't Hoff/Le Bel motifs for study.

Thermal decomposition of aluminum isopropoxide (AIP) in toluene at 315 ํC for 2 h gave chi-alumina product having the high thermal stability and while the reaction at lower temperature resulted in formation of an amorphous product. The thus-obtained chi-alumina transformed directly to alpha-alumina at approximately 1150 ํC, bypassing other transition alumina phases. The amorphous product transformed to gamma-alumina then to theta-alumina, after calcination at high temperature. It was found that when chi-alumina synthesized at 315 degree celicus was recovered by the removal of the solvent at the reaction temperature, the product showed the highest thermal stability. This procedure is convenient avoiding bothersome work-up process yielding large surface area and large pore volume alumina. Thermal decomposition of AIP in mineral oil at 250-300 degree celcius over a 2 h duration results in chi-alumina powders having high thermal stability. The mechanism of the process involves the formation of amorphous complex before further decomposition takes place. Phase transformation of the obtained products was also investigated. It was found that chi-alumina synthesized by this method transformed directly to alpha-alumina at temperature higher than 1000 degree celcius. chi-alumina prepared in both organic solvents attains a critical crystallite size around 15 nm through accretion on calcination and then transforms directly to alpha-alumina through nucleation and growth process

To be commercialized photovoltaic panels, one of the most important issue is the stability. Normally, thin-film perovskite solar cells have been suffered from it. Contrary, carbon-based multi-porous-layered-electrodes perovskite solar cells (MPLE-PSCs) have enough stability for it. Specially, the porous carbon electrodes have five merits for the stability as below,[1] high stability against halogen in perovskite crystal (Au and Ag can be damaged by the halogen)[2] high conductivity to be the back contact electrodes (the sheet resistance can be around 5 ohm/square)[3] strong hole-extraction ability (in place of organic hole-transporting material)[4] water absorption ability as activated carbon after annealing procedure at 400 °C[5] water blocking ability after making photovoltaic device with perovskite crystalHence, such porous carbon electrodes enhance the stability of MPLE-PSCs. Moreover, the merits for the commercialization of MPLE-PSCs can be listed as,[1] high stability against high temperature and strong radiation against sun illumination1-1 Thermal stability at 100 ֩C over 4500 h in dark (by Univ. of Hyogo, Japan).1-2 Damp-heat stability at 85 ֩C-85%RH over 3,000 h in dark (by Univ. of Hyogo and Kishu Giken Kogyo, Japan).1-3 Light stability at 55 ֩C over 10,000 h (by EPFL, Switzerland ).[2] relatively photoenergy conversion efficiency for the utilization (11.5% as module)[3] cost-effective fabrication process by fully-printing method under ambient air (without glove box and dry room)[4] Recyclable deviceIn the conference, the fabrication technology and the challenging works of high thermal stability at 140 ֩C will be presented.

Metal-supported SOFCs are very attractive due to their high mechanical strength, thermal conductivity, and low material cost. These properties make SOFCs suitable for mobile application as well as the traditional stationary application. Contrary to many researches, using the thin-metal support will be more suitable for potable application because it provides the cell with flexibility, light weight, and good stacking property. In this study, thin metal-supported SOFC (~100μm) was fabricated and tested. Green sheets of thin STS support, Ni-YSZ anode, and YSZ electrolyte were prepared by tape casting method in order to fabricate the single cell. Three tapes were laminated and co-fired at 1300oC in reducing atmosphere. Microstructure of 3-layered cell was examined and the performance was tested with a LSCF cathode at 800oC. Thin and strong metal-supported SOFC was successfully fabricated by co-firing process. Total thickness of the sintered cell was ~80μm. This thin cell showed flexible nature and was easily bent without visible cracks on the electrolyte. The Cr-poisoning of Ni in the anode was occurred during sintering at high temperature, which could lower the cell performance. Cr diffusion barrier may be used in order to enhance the cell performance.