Author Keywords: Carbon dioxide; Hydrogenation; Hydrogenolysis; Methanol; Ethyl formate 相似文献
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1.
Zhi-xue Tian Akifumi Uozumi Ikutaro Hamada Susumu Yanagisawa Hidetoshi Kizaki Kouji Inagaki Yoshitada Morikawa 《Nanoscale research letters》2013,8(1):203
First-principles calculations were performed to investigate the effect of Pd concentration and oxygen vacancies on the stability of Pd at LaFeO3 surfaces. We found a much stronger tendency of Pd to segregate by taking the aggregation of Pd at LaFe1-xPdxO3-y surfaces into consideration, resulting in a pair of Pd-Pd around a vacancy. Moreover, we predicted that one oxygen-vacancy-containing FeO2-terminated surfaces would be stable at high temperatures by comparing the stability of LaFe1-xPdxO3-y surfaces, which further supports our previous conclusion that a Pd-containing perovskite catalyst should be calcined at 1,073 K or higher temperatures in air to enhance the segregation of Pd in the vicinity of surfaces to rapidly transform the Pd catalyst from oxidized to reduced states on the perovskite support. 相似文献
2.
Hiroshi Yamashita Marites S de LeonSomruethai Channasanon Yoshitada SuzukiYuko Uchimaru Kazuhiko Takeuchi 《Polymer》2003,44(23):7089-7093
The Pd-PCy3 (Cy=cyclohexyl) system effectively catalyzed hydrosilylation polymerization of dihydrosilanes with p- or m-diethynylbenzene to give silylene-divinylene polymers with Ph, Me, and/or vinyl substituents at the silicon atoms. The resulting polymers showed characteristic absorption and fluorescence spectra in ultraviolet to visible region. p-Phenylene polymers displayed λmax peaks in longer wavelength region than the corresponding m-phenylene polymers. In TGA, the 5% weight loss temperatures (Td5) ranged from 436 to 501 °C, indicating rather high thermal stability of these polymers. Vinyl group-containing polymers exhibited higher Td5 values and char yields than other polymers. 相似文献
3.
Uniform and symmetric membranes were formed from poly(methyl methacrylate) (PMMA) by making use of the stereocomplex phenomenon which characteristically occurs in the solution of a mixture of isotactic PMMA and syndiotactic PMMA. The water permeability of the membrane was very high compared to a commercially available cellulosic membrane, whereas their NaCl permeabilities were the same. The permeabilities of the membranes are explained by a simple capillary model. By varying the tacticity of the polymer it was found that the finest membrane structure is formed at the isotactic polymer ratio of ca. 30%. This shows the close relationship between complex formation and membrane permeability. 相似文献
4.
We have investigated the initial stage of hydrolysis process of Ga-terminated GaN surfaces by using first-principles theoretical calculations. We found that the activation barrier of H2O dissociation at the kinked site of the Ga-terminated GaN surface is about 0.8 eV, which is significantly lower than that at the stepped site of about 1.2 eV. This is consistent with the experimental observation where a step-terrace structure is observed after the etching process of Ga-terminated GaN surfaces with catalyst-referred etching method. Detailed analysis on the nature of the chemical interaction uring the hydrolysis processes will be discussed. 相似文献
5.
Hensy Gandjar Yuki Takagi Naoki Matsuzuka Yoshitada Isono 《IEEJ Transactions on Electrical and Electronic Engineering》2008,3(3):260-267
This work describes a scanning probe parallel nanolithography (SPNL) technique for high throughput in nanometric patterning on single‐crystal silicon (SCS) substrates. Two types of multiprobe cantilever arrays used for SPNL were fabricated by conventional micromachining. All the probes mounted on the free end of each cantilever were made of quasitrihedral pyramidal shape composed of (311) and (411) planes using the originally designed mask. Negative and positive types of nanolithography were performed on the basis of field‐enhanced anodization and self‐assembled monolayer mask techniques, respectively, and they succeeded in drawing a number of nanometric patterns of silicon dioxide (SiO2) on SCS substrates. After anisotropic wet etching of the SCS substrates using the SiO2 films as the mask material, we were also able to fabricate nanowires and nanogrooves. The effects of the applied voltage and scan time of cantilever arrays on wire and groove dimensions were systematically examined by atomic force microscopy (AFM) observations. An optimum condition for the parallel SPNL is proposed on the basis of this research. © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
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7.
Hyun‐Jin Oh Yoshitada Isono Takahiro Namazu Yoshihiro Saito Akira Yamaguchi 《IEEJ Transactions on Electrical and Electronic Engineering》2008,3(3):281-289
This paper investigates the influence of gas flow ratio in the preparation of submicron‐thick silicon nitride (SiNx) films on their elastic properties. SiNx films with a thickness ranging from 0.14 to 0.69 µm were deposited by plasma‐enhanced chemical vapor deposition (PE‐CVD) onto 10‐µm‐thick single‐crystal silicon (SCS) specimens by changing the gas flow ratio of monosilane (SiH4) to ammonia (NH3) to nitrogen (N2). A uniaxial tensile tester operated under an atomic force microscope (AFM) characterized the Young's modulus of SiNx films and the fracture strength of SiNx/SCS laminated specimens. The Young's modulus of SiNx films ranged from 99.5 to 144.3 GPa, which increased with the gas flow ratio but was independent of the film thickness. Nano‐indentation tests were also carried out to examine the Poisson's ratio of SiNx films in addition to the tensile tests. The Poisson's ratio was found to be 0.19 to 0.27, on average. Auger spectroscopy revealed that an increase of the atomic content ratio of nitrogen (N) to silicon (Si) in SiNx films yielded higher elastic constants of the films. © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
8.
Mechanical property measurements of nanoscale structures using an atomic force microscope 总被引:7,自引:0,他引:7
This paper describes nanometer-scale bending tests of fixed single-crystal silicon (Si) and silicon dioxide (SiO2) nanobeams using an atomic force microscope (AFM). The technique is used to evaluate elastic modulus of the beam materials and bending strength of the beams. Nanometer-scale Si beams with widths ranging from 200 to 800 nm were fabricated on a Si diaphragm using field-enhanced anodization using an AFM followed by anisotropic wet etching. Subsequent thermal oxidation of Si beams was carried out to create SiO2 beams. Results from the bending tests indicate that elastic modulus values are comparable to bulk values. However, the bending strength appears to be higher for these nanoscale structures than for large-scale specimens. Observations of the fracture surface and calculations of the crack length from Griffith's theory appear to indicate that the maximum peak-to-valley distance on the beam top surfaces influence the values of the observed bending strengths. 相似文献
9.
Koji Takahashi Yoshitada Nishio Yoshiki Kimura Kotoji Ando 《Journal of the European Ceramic Society》2010,30(15):3047-3052
In this study we propose a new method for improving the surface strength and reliability of ceramics that combines shot peening with crack-healing ability. We used Si3N4/SiC composite ceramics with high crack-healing ability and subjected the specimens to shot peening and crack healing. To evaluate the effect of our method, we investigated the residual stress after shot peening and crack healing and examined the specimens’ mechanical properties, including apparent fracture resistance, contact strength and bending strength. We found that shot peening and crack healing is effective to increase apparent fracture resistance, contact strength and bending strength. 相似文献
10.
Low-temperature methanol synthesis from carbon dioxide and hydrogen via formic ester 总被引:2,自引:0,他引:2
A new route of methanol synthesis, at 443 K and under pressurized conditions, from carbon dioxide and hydrogen through formic ester was investigated, by using Cu-based catalysts. This one-pot reaction consisted of three steps:
1. formic acid synthesis from CO2 and H2,
2. esterification of formic acid by ethanol to ethyl formate, and
3. hydrogenolysis of ethyl formate to methanol and ethanol.