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排序方式: 共有989条查询结果,搜索用时 156 毫秒
981.
982.
Peter A. Banks Gabriele D'Avino Guillaume Schweicher Jeff Armstrong Christian Ruzié Jong Won Chung Jeong-Il Park Chizuru Sawabe Toshihiro Okamoto Jun Takeya Henning Sirringhaus Michael T. Ruggiero 《Advanced functional materials》2023,33(38):2303701
Organic semiconductors with distinct molecular properties and large carrier mobilities are constantly developed in attempt to produce highly-efficient electronic materials. Recently, designer molecules with unique structural modifications have been expressly developed to suppress molecular motions in the solid state that arise from low-energy phonon modes, which uniquely limit carrier mobilities through electron–phonon coupling. However, such low-frequency vibrational dynamics often involve complex molecular dynamics, making comprehension of the underlying electronic origins of electron–phonon coupling difficult. In this study, first a mode-resolved picture of electron–phonon coupling in a series of materials that are specifically designed to suppress detrimental vibrational effects, is generated. From this foundation, a method is developed based on the crystalline orbital Hamiltonian population (COHP) analyses to resolve the origins—down to the single atomic-orbital scale—of surprisingly large electron–phonon coupling constants of particular vibrations, explicitly detailing the manner in which the intermolecular wavefunction overlap is perturbed. Overall, this approach provides a comprehensive explanation into the unexpected effects of less-commonly studied molecular vibrations, revealing new aspects of molecular design that should be considered for creating improved organic semiconducting materials. 相似文献
983.
Toshihiro Ishikawa Katsuya Niidome 《International Journal of Applied Ceramic Technology》2022,19(2):876-881
Surface functionalization of titanium metal is very attractive for bio- and environmental applications. This is because titanium metal is very stable and has a good biocompatibility. In this case, surface roughness and crystalline structure are important factors for obtaining effective characteristics. Titanium metal is usually covered with a surface passive film of thermodynamically stable rutile-TiO2 that grows as the heat treatment temperature in air increases. On the other hand, to obtain an anatase-TiO2 surface layer on titanium metal, we must employ specific treatments such as our previous method, which uses a silica-coexisting heat-treatment process. In this paper, the relationship between the fine structure formed on the titanium metal and the surface hydrophilic property was clarified, and the potential for the bio-application was discussed. The formed anatase-TiO2 coexisting with silica exhibited improved biocompatibility with good apatite formation. 相似文献
984.
Keiji Saiki Toshihiro Ishikawa 《International Journal of Applied Ceramic Technology》2023,20(3):1388-1397
Silica–titania mixed oxides have excellent properties, such as a low thermal expansion coefficient and a refractive index that can be adjusted by changing the Ti content. However, when the Ti content increases, silica and titania phases in silica–titania mixed oxides can separate. This phase separation leads to the precipitation of the titania component as rutile or anatase crystals. When silica–titania mixed oxides undergo phase separation, their properties become unstable; for example, the refractive index of the particles becomes non-uniform. Therefore, it is preferable to synthesize silica–titania mixed oxides in an amorphous state without causing phase separation. Based on our previous studies on particle size control in silica synthesis, we employed a dry process using organosilicon compounds to synthesize silica–titania mixed oxides. In this study, spherical amorphous silica–titania mixed oxide particles were obtained via flame synthesis using organosilicon and organotitanium compounds. The purpose of this study was to characterize the obtained powder and explore the possibility of controlling particle size during synthesis. By studying the dry process synthesis of spherical silica–titania mixed oxide particles, we confirmed the relationships: between the Si/Ti molar ratio and the obtained crystal structure and between the adiabatic flame temperature and the particle size. 相似文献
985.
Shota Daiki Toshihiro Ishikawa 《International Journal of Applied Ceramic Technology》2023,20(4):2603-2609
Hexagonal boron nitride (h-BN) particles exhibit high thermal conductivity and are promising fillers for resin filling. However, h-BN particles are plate-like particles with thermal anisotropy in the planar and thickness directions. Therefore, their applications are limited due to low thermal conductivity in the direction of the thickness of a resin sheet filled with h-BN particles. In this study, we control the size and thickness of h-BN particles using carbothermal reduction nitridation (CRN), which involves the carbothermic reduction of boric oxide in an N2 gas atmosphere and develop them into resin sheets. In CRN using a CaO promoter, a novel method is developed to control the shape, size, and thickness of h-BN particles. Using h-BN particles grown in the thickness direction, we have successfully provided resin sheets with high thermal conductivity. 相似文献
986.
Akira Kondo Takahiro Kozawa Toshihiro Ishii Makio Naito 《International Journal of Applied Ceramic Technology》2023,20(2):700-707
In this study, NH4CoPO4·H2O (ACP) platelets were synthesized from NH4H2PO4 and Co(OH)2 by wet milling process using a bead mill. ACP is one of the precursors of LiCoPO4 (LCP) cathode materials for Li-ion batteries. In the wet milling, ACP large platelets were synthesized in a short time at the beginning, and the large platelets were gradually cleaved into the smaller platelets. The lateral sizes of the ACP platelets were several 10 μm at 30 min and about 10 μm at 5 h. It was found that the ACP platelets were synthesized efficiently by using the bead mill as a promising machine for the scale-up in manufacturing. The ACP platelets were converted into LCP by mixing with Li2CO3 and heating, whereas platelet shapes were retained. The initial discharge capacities of the cathodes using the LCP platelets converted from the ACP of 30 min and 5 h milling were 70 and 95 mAh/g at 0.05 C, respectively. It is because the specific surface area of the latter sample (3.3 m2/g) was larger than that of the former (2.2 m2/g). The larger specific surface area possibly led to the increase of contacts with electron conductive additives (carbon) and electrolytes. 相似文献
987.
988.
Akira Kondo Takahiro Kozawa Toshihiro Ishikawa Makio Naito 《International Journal of Applied Ceramic Technology》2022,19(2):681-687
In this study, synthesis of yttrium aluminum garnet (YAG):Ce3+ phosphor powders for white light emitting diodes was investigated by mechanical method using the attrition-type mill with no external heating and no flux in dry phase. High mechanical energy input to the starting powder mixture of Y2O3, Al2O3 and CeO2 achieved the synthesis of YAG:Ce3+ without any flux materials. X-ray diffraction patterns of the processed powders after 5 min processing revealed the peaks of YAG were clearly identified. The maximum temperature of the mill chamber during the processing was 240℃. The YAG phosphor obtained by the mechanical method revealed the internal quantum yield of 65% in the case of the sample mechanically processed under a reducing atmosphere. The synthesized powder showed granule structure consisting of submicron size of YAG particles, which is better handling for the fabrication of light emitting diode devices. 相似文献
989.
Toshihiro Ishikawa Katsuya Niidome 《International Journal of Applied Ceramic Technology》2023,20(3):1432-1441
This paper provides an innovative controlling process of surface morphology. The contact area between a liquid and a solid is strongly affected by the critical surface tension (cft) of both materials. Using this phenomenon, a wide range of morphologies, from flat surface layers to sea-grape-like surface structures, were created. Due to the bleed-out phenomenon, low-molecular-mass additive (liquid) oozed out of a precursor polymer (solid), leading to different surface morphologies depending on the cft values of the liquid (Mcft) and solid (Pcft). When Mcft < < Pcft, a flat surface layer was obtained; however, in the case of Pcft < < Mcft, the formation of a sea-grape-like surface layer was created. Tetra-butoxy-titanium and polydimethylsiloxane were used as low-molecular-mass additive and precursor polymer, respectively. After coating on titanium metal and calcination, sea-grape-like materials composed of titanium oxide and silicon oxide were obtained. Furthermore, unique characteristics (bioactivity, photocatalytic activity, and prevention of atomic diffusion) were observed. A remarkable increase in the wettability, bioactivity, and catalytic activity of materials was achieved using our simple process to create unique surface morphologies. Our proposed process is applicable to a wide range of materials and morphologies, and can be used in catalysts, biomaterials, and environmental barrier coatings. 相似文献