The influence of internal electrode material on the sintering of mixed-sintering ceramics and the effect of MnO2 additive on improving their dielectric properties were investigated for their application as multilayer ceramic capacitors. The resistivities of mixed-sintering ceramic pellets sintered with Ag-Pd electrode material decreased remarkably because of the expulsion of component elements during sintering. A small amount of MnO2 additive improved the resistivities. Extended X-ray absorption fine-structure analysis showed that MnO2 exists in the grain boundaries and compensates for the electrical valence of the expelled elements. 相似文献
Elastic neutron diffraction measurements were performed on single crystals to study the ground state below the mysterious exotic transition temperature 0.86 K. An antiferromagnetic order with a tiny moment of 0.027μB per formula is formedas the ground state for CeOs4Sb12 below the transition point. Our neutron data gives the evidence of spin density wave state for CeOs4Sb12 in this work. 相似文献
Nowadays our society demands the reuse of industrial products. Then we should not only re-investigate the materials of products but also originate a new design method of industrial products. We have investigated the cellular structure by using abandoned paper, because the cell's shape can be proposed arbitrarily by folding a paper. As examples, we have proposed the structure constructed by connecting many folded cells formed in a hexagonal cross area. This structure will have characteristics such as almost high rigidity, high stiffness, crushing stress, relative insensitivity to the overall loss of stability. To estimate the characteristics of these structures, we must analyze the deformation in loading. When the structure with thin walls formed by paper is loaded, the shape of deformation is different from that of the metal, wall swells and does not maintain its flatness. Therefore, we cannot apply the traditional theory of elasticity for the analysis. In this paper, we propose a new estimation method by analyzing the swelling. 相似文献
The electrochemical reduction of CO2 on a Cu electrode was investigated in aqueous NaHCO3 solution, at low temperature. A divided H-type cell was employed, the catholyte was 0.65 mol dm−3 NaHCO3 aqueous solution and the anolyte was 1.1 mol dm−3 KHCO3 aqueous solution. The temperature during the electrolysis of CO2 was decreased stepwise to 271 K. Methane and formic acid were obtained as the main products. The maximum Faradaic efficiency of methane was 46% at −2.0 V and 271 K. The efficiency of hydrogen formation, a competing reaction of CO2 reduction, was significantly depressed with decreasing temperature. Based on the results of this work, the proposed electrochemical method appears to be a viable means for removing CO2 from the atmosphere and converting it into more valuable chemicals. The synthesis of methane by the electrochemical method might be of practical interest for fuel production and the storage of solar energy. 相似文献
Tritium radioluminography has been applied to determine the hydrogen (H) diffusion coefficients in Ti50Cr50 and Ti40Cr60 alloys, both with two-phase structures of a body-centered cubic (bcc) phase and a Laves phase. Using radioluminography, H distributions in those phases have been observed, and H penetration profiles have been measured. The tritium diffusion coefficients in the Ti50Cr50 and Ti40Cr60 alloys have been successfully determined by analyzing the tritium penetration profiles to be 3.3±0.3 × 10?12 and 1.4±0.1×10?12 m2/s, respectively. These values suggest that the H diffusion in the Laves phase is slower than that in the bcc phase. It is also suggested that H diffuses by short-circuiting diffusion through the interface between the bcc phase and the Laves phase. 相似文献
Several azacrown ether derivatives, which are monoaza-12-crown-4, -15-crown-5, and -18-crown-6 and diaza-12-crown-4 and -18-crown-6, bearing one or two spirobenzopyran(s), which we call crowned spirobenzopyran or crowned bis(spirobenzopyran), were synthesized and were used as carriers for liquid membrane transport of alkali metal ions. The passive alkali metal transports through liquid membranes containing crowned spirobenzopyrans were carried out under dark, and UV- and visible-light irradiation conditions. The metal ion transport was accelerated and retarded by UV- and visible-light irradiation, respectively. On the other hand, the photoresponse of the metal ion selectivity in membrane transport by crowned spirobenzopyrans was different, depending on the kind of crown ether units. Especially, diaza-12-crown-4-bis(spirobenzopyran) exhibited an excellently selective and effective transporting ability for Li(+). The uphill transports of Li(+) through a liquid membrane containing monoaza-12-crown-4-spirobenzopyran or diaza-12-crown-4-bis(spirobenzopyran) were realized under the conditions where the same aqueous solution was used as the source and receiving phases with UV and visible lights being irradiated onto the boundary phases between the source and membrane phases and between the receiving and membrane phases, respectively. The uphill transport of Li(+) from the source to receiving phases through a liquid membrane containing a crowned spirobenzopyran was also attained by the proton-concentration gradient between the source and receiving phases under dark conditions, and the transporting ability was remarkably increased by photoirradiation. 相似文献
Cavities formed by proteins have been utilized as the reaction chamber for the fabrication of a range of inorganic nanoparticles, providing control of the size of particles by limiting growth and preventing agglomeration. In crystal form, proteins construct molecular arrays that can provide regularly arranged sites for nanoparticles. Here we report the fabrication of nanometric iron and indium particles using ferritin, an iron-storage protein. The indium nanoparticles thus formed have uniform spherical shape with diameter of 6.6 +/- 0.5 nm, while the iron nanoparticles are somewhat irregular in shape (5.8 +/- 1.0 nm). Regular two-dimensional arrays of these nanoparticles are successfully produced by crystallizing ferritin molecules on a water-air interface using the denatured protein film method. The lattice constant of these nanoparticle arrays is 13 nm with hexagonal packing, and arrays of more than 1 microm in area can be obtained by transfer onto silicon wafer. 相似文献
A method that combines UV irradiation and pausing was developed to manipulate the regularity and the length scales of the morphology generated by phase separation in full‐interpenetrating polymer networks of polystyrene and poly(methyl methacrylate). Upon increasing the pause time of photopolymerization and photo‐crosslink processes, the morphology gradually changes from hexagonal‐like packing to random structures. The width of the loss tan δ obtained for these phase‐separated materials changes with the morphological regularity, suggesting a potential technique for fabrication of mechanical bandgap materials.