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Express Letter
published : Advance online publication
Jiazhuo PENG, Heping LI and Sen LIN
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High-pressure sintering method was used to prepare the proton conductor based on BaZr0.7Ce0.2Y0.1O3−δ for the first time, and a comparative research of traditional pressureless sintering and high-pressure sintering methods was carried out. High-pressure sintering accelerated the sintering densification and greatly lowered the sintering temperature, resulting in high performance BaZr0.7Ce0.2Y0.1O3−δ product which was expected to be used as solid electrolyte to fabricate a sensor for measuring hydrogen in high-pressure hydrothermal systems.
Full Paper
published : vol. 128, no.1, January 2020
Teruaki FUCHIGAMI, Xie DI and Ken-ichi KAKIMOTO
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An integrated approach using anionic polymer sources and conventional spray drying technology was proposed to synthesize inorganic particles covered with single layer of fine particles. Negatively charged poly(acrylic acid) adsorbed on the two particles even though the particles had negative charge and assisted to disperse them individually in suspension. The dispersed 0.25 µm Fe3O4 was uniformly accumulated with single layer on 2.0 µm BaTiO3 particles by their condensation in shrinking sprayed droplets. The poly(acrylic acid) molecules which adsorbed on both particles had a function to bind the two particles, and the Fe3O4 fine particles were fixed on BaTiO3 particles persistently and discretely. The poly(acrylic acid)-assisted spray drying method is applicable for any combination of various functional particles.
The 73th CerSJ Awards for Advancements in Ceramic Science and Technology: Review
Special Article
published : vol. 128, no.1, January 2020
Kunimitsu KATAOKA
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Li6.5La3Zr1.5Nb0.5O12 and Li6.5La3Zr1.5Ta0.5O12 single-crystal rods were grown by floating zone melting. A typical single-crystal rod is 8 mm in diameter and 70 mm in length. Crystallized Li6.5La3Zr1.5Nb0.5O12 and Li6.5La3Zr1.5Ta0.5O12 have cubic structures in the I21d space group. The crystal structures of Li6.5La3Zr1.5Nb0.5O12 and Li6.5La3Zr1.5Ta0.5O12 belong to the cubic I213 space group, while the final structure refinements were performed based on an approximate space group Ia−3d. The lattice parameter (a) of Li6.5La3Zr1.5Nb0.5O12 was 12.9130(8) Å (1 Å = 0.1 nm), while that of Li6.5La3Zr1.5Ta0.5O12 was 12.9455(6) Å. The crystallographic reliability factors (R-values) of the Li6.5La3Zr1.5Nb0.5O12 and Li6.5La3Zr1.5Ta0.5O12 crystal structures were 7.09% (wR = 7.94%) and 8.82% (wR = 7.45%), respectively, based on the single-crystal neutron diffraction data. Li ions in the crystal structures occupied both distorted tetrahedral 96h sites and distorted octahedral 96h sites. From the results of alternating current impedance measurements, we estimated the total Li-ion conductivity of Li6.5La3Zr1.5Nb0.5O12 and Li6.5La3Zr1.5Ta0.5O12 at 298 K to be 1.39 × 10−3 and 1.27 × 10−3 S cm−1, respectively. These are the highest conductivities reported to date for Li6.5La3Zr1.5Ta0.5O12 members. The bulk properties of garnet-type electrolyte single crystals were advantageous for bulk conductivity and lacked the grain boundaries characteristic of sintered polycrystalline bodies. These solid electrolytes represent a game-changing technology for realizing advanced battery systems with strong safety features.
Full Paper
published : vol. 128, no.1, January 2020
Juan XIE, Ming DUAN, Penghui BAI and Hu WANG
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The shift of photonic bandgap could be used to study the adsorption behavior of concentration. However, there are so many issues need to explore in this field, such as adsorption models and influence factors. In this paper, it is found that the size of initial particles has a great impact on the size of silica colloidal spheres and the volume fraction of pore, resulting in the different adsorption behavior on the surface of silica photonic crystals. The effect of initial particle size on colloidal spheres and volume fraction of pore are investigated. Furthermore, the effect of initial particle size on gas adsorption behavior has been discussed by using the volume fraction of adsorption vapor (Vvap). It can be seen that the trends of isopropanol adsorption differ from methanol and ethanol.
Full Paper
published : vol. 128, no.1, January 2020
Hidekatsu MOROZUMI, Satoshi YOSHIDA and Jun MATSUOKA
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This study reports the strengthening effect of partially substituting SiO2 with B2O3 in aluminoborosilicate (ALBS) glasses. Specifically, it investigates how the B2O3 addition affects the ion-exchange behavior of the glass. The base composition of ALBS glass is 13Na2O–5K2O–7MgO–15Al2O3–12B2O3–48SiO2 (mol %). In the prepared samples, the proportion of B2O3 was varied from 0 to 16 mol %. The Na+/K+ inter-diffusion coefficient of each sample was estimated from the K+ ion concentration profile collected along the cross-section of each sample after immersion in molten KNO3 at (Tg × 0.83) K (where Tg is the glass transition temperature) for 8 h. Adding only a small amount of B2O3 drastically changed the K+ ion concentration profile. In contrast, the activation energy of the Na+/K+ inter-diffusion was almost independent of B2O3 content. These results suggest that the B2O3 incorporated in the glasses simply acts as a flux component. These findings are useful for designing compositions that strengthen ion-exchanged glasses.
Full Paper
published : vol. 128, no.1, January 2020
Hidetoshi MIYAZAKI and Jun IMAGUCHI
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Ba3Si6O12N2:Eu2+ and Ba3Si6O9N4:Eu2+ phosphors were synthesized by a solid-state reaction using Si2N2O powder as the starting material. The Ba3Si6O12N2:Eu2+ phosphor showed green photoluminescence (PL) with a peak at 517 nm, while Ba3Si6O9N4:Eu2+ showed bluish-green PL with a peak at 490 nm. Additionally, both phosphors exhibited afterglow properties.
Technical Report
published : vol. 128, no.1, January 2020
Takamasa KANEKO, Fukue NAGATA, Shinichi KUGIMIYA and Katsuya KATO
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In this study, porous zirconia (PZ) was synthesised by sol–gel process and evaluated for the adsorption of milk proteins such as β-casein and β-lactoglobulin. The particles manifested an extremely good adsorption affinity for β-casein, with very short adsorption times. In addition, increasing of the adsorption times afforded aggregation of the β-casein-adsorbed particles. Adsorption–desorption experiments, carried out by immersing the PZ in HEPES buffer solution containing 2 M sodium chloride, revealed that only a small amount of adsorbed β-casein was leached from the particles, which suggests that the protein was tightly adsorbed. Taken together, the results obtained suggest that the strong adsorption affinity and specific adsorption behaviour of PZ for the phosphate group render it a promising candidate for the development of phosphoprotein adsorbents.
Note
published : vol. 128, no.1, January 2020
Liwei FANG, Liangbiao WANG, Lei JIANG, Ciyang ZHANG, Tingting ZHOU, Zhe CHEN, Li LI, Xueping ZHU, Yipeng ZHU and Tinghai YANG
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Nitridation of oxides is a conventional method to prepare nitrides. However, this method has a disadvantage of requiring a high reaction temperature. Additive-assisted nitridation is an effective route to synthesize nitrides at low temperature. In this study, hexagonal phase indium nitride (InN) nanomaterials have been successfully synthesized through the nitridation of indium hydroxide by sodium amide in a stainless-steel autoclave at a low temperature (250–300°C), in which sodium thiosulfate acts as an additive. Scanning electron microscope image shows that the as-obtained InN sample is composed of nanoparticles and nanosheets. The influences of the reaction temperature on the as-obtained product have also been investigated.
Note
published : vol. 128, no.1, January 2020
Withanage ISURU UDAKARA WITHANAGE, Nobuhiro KUMADA, Takahiro TAKEI, Sayaka YANAGIDA, Kiyoharu TADANAGA, Akira MIURA, Nataly Carolina ROSERO-NAVARRO and Masaki AZUMA
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Pyrochlore-type silver tantalate, Ag0.93TaO2.97·0.94H2O (AT), and fluorite-type silver niobate Ag0.41Nb0.59O1.68 (AN), were prepared by ion-exchange reactions and their ion conductivities were measured from 25 to 240°C. The total conductivities (ionic + electrical) at 240°C of AT and AN reached 4.00 × 10−3 and 9.03 × 10−4 S/cm, respectively. The activation energy of AT was 0.61 eV and AN showed non-linear behavior with activation energies of 0.52 eV at temperatures less than 120°C and 0.33 eV at temperatures greater than 120°C. The crystal structures of AT and AN were maintained from 25 to 240°C.
Note
published : vol. 128, no.1, January 2020
Masataka OGASAWARA, Takuto BAN, Kanji SAITO and Sumio KATO
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Inorganic–organic composites have been prepared using Dion–Jacobson-type layered perovskite compounds as base catalysts. Dodecyltributylphosphonium bromide (C12TBPBr), dodecyltriphenylphosphonium bromide (C12TPPBr), or dodecyltrimethylammonium chloride (C12TMACl) were used as the organic species of the inorganic–organic composite. It was suggested that C12TBP+, C12TPP+, or C12TMA+ were intercalated by ion-exchange with interlayer H+ of HCa2Nb3O10. The acid–base reaction was evaluated by consecutive deacetalization–Knoevenagel reactions. The product of the second-step reaction of the inorganic–organic composite catalysts was obtained, which suggested that the composites were acid–base bifunctional materials. For composites prepared using HCa2Nb3−xTaxO10 (x = 1, 2, and 3) as inorganic species, the base catalytic activity decreased with decreasing fraction of organic species. Therefore, the hydrophobicity of the layered compounds affected the catalytic activity of the composite. Various catalysts should be prepared using reported layered perovskite-type compounds having various compositions.