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排序方式: 共有1687条查询结果,搜索用时 31 毫秒
21.
Koki Murano Tomoyoshi Shimobaba Atsushi Sugiyama Naoki Takada Takashi Kakue Minoru Oikawa Tomoyoshi Ito 《Computer Physics Communications》2014
We report fast computation of computer-generated holograms (CGHs) using Xeon Phi coprocessors, which have massively x86-based processors on one chip, recently released by Intel. CGHs can generate arbitrary light wavefronts, and therefore, are promising technology for many applications: for example, three-dimensional displays, diffractive optical elements, and the generation of arbitrary beams. CGHs incur enormous computational cost. In this paper, we describe the implementations of several CGH generating algorithms on the Xeon Phi, and the comparisons in terms of the performance and the ease of programming between the Xeon Phi, a CPU and graphics processing unit (GPU). 相似文献
22.
The interface area between the bubble and emulsion phases in a fluidized catalyst bed is one of the important parameters used to analyze and design the fluidized bed reactor. We used a fast‐scanning X‐ray CT system to observe the bubble shape and structure. We then obtained the transient 2‐dimensional cross sectional gas‐phase distribution in a fluidized catalyst bed. Using image‐processing techniques, pseudo 3‐dimensional images of the bubbles were reconstructed. The bubble structure was studied based on the 3‐dimensional images and the previously obtained results in a 2‐dimensional fluidized bed. It was found that the bubble shape was not spherical but complicated, and that the bubbles ascending in a fluidized catalyst bed consisted of some smaller bubbles. 相似文献
23.
T.?Sonoda Y.?Takata S.?Ueno K.?SatoEmail author 《Journal of the American Oil Chemists' Society》2004,81(4):365-373
The crystallization and polymorphic behavior of palm stearin (PS) in a bulk state and in oil-in-water (O/W) emulsion droplets
(average diameter, 1.7±0.3 μm) was observed by using DSC, optical microscopy, and in situ X-ray diffraction with synchrotron radiation (SR-XRD). For the bulk sample the DSC measurements revealed three main exothermic
peaks at approximately 31 (large), 21 (small) and 3°C (medium) on cooling, and broad endothermic peaks at approximate −3 (small),
8, 15 to 25 (medium), and 37 and 53°C upon heating. The SR-XRD patterns taken during cooling from 60 to −5°C clarified that
the DSC exothermic peaks around 31 and 3°C corresponded to crystallization of the α form of high-melting and low-melting fractions,
respectively, and that the occurrence of β′ corresponded to the small exothermic peak around 21°C. The XR-XRD patterns taken
during heating from −5 to 60°C demonstrated that the DSC endothermic peaks corresponded to the following transformation processes:
melting of α of the low-melting fraction (−3°C), melt-mediated transformation from α to ∇′ (15–25°C), melting of β′ (36°C),
and melting of β (53°C) of the high-melting fraction. As for the O/W emulsion sample, the DSC and SR-XRD measurements during
the cooling and heating processes exhibited basically the same behavior as that of PS in the bulk state, except that β′ did
not crystallize during the cooling process, and the temperatures of crystallization of α, melt-mediated α→β′→β transformation,
and melting of β were lower in the emulsion droplets than in the bulk state. 相似文献
24.
Effects of Annealing on Dielectric Loss and Microstructure of Aluminum Nitride Ceramics 总被引:1,自引:0,他引:1
Shoichi Kume Masaki Yasuoka Naoki Omura Koji Watari 《Journal of the American Ceramic Society》2005,88(11):3229-3231
The effect of annealing on tan δ and microstructures of aluminum nitride (AlN) ceramics were explored. Yttria was added as a sintering additive to AlN powders, and the powders were pressureless-sintered at 1900°C for 2 h in a nitrogen flow atmosphere. In succession to sintering, AlN samples were annealed at 720, 970 and 1210°C for 2 and 4 h. Very low tan δ values between 2.6 and 6.0 × 10−4 at 28 GHz were obtained when the AlN samples were annealed for 4 h at all the annealing temperatures. 相似文献
25.
Yu-Ping Zeng Jian-Feng Yang Naoki Kondo Tatsuki Ohji Hideki Kita Shuzo Kanzaki 《Journal of the American Ceramic Society》2005,88(6):1622-1624
The fracture energies of the tape-cast silicon nitride with and without 3 wt% rod-like β-Si3 N4 seed addition were investigated by a chevron-notched-beam technique. The material was doped with Lu2 O3 –SiO2 as sintering additives for giving rigid grain boundaries and good heat resistance. The seeded and tape-cast silicon nitride has anisotropic microstructure, where the fibrous grains grown from seeds were preferentially aligned parallel to the casting direction. When a stress was applied parallel to the fibrous grain alignment direction, the strength measured at 1500°C was 738 MPa, which was almost the same as room temperature strength 739 MPa. The fracture energy of the tape-cast Si3 N4 without seed addition was 109 and 454 J/m2 at room temperature and 1500°C, respectively. On the contrary, the fracture energy of the seeded and tape-cast Si3 N4 was 301 and 781 J/m2 at room temperature and 1500°C, respectively, when a stress was applied parallel to the fibrous gain alignment. The large fracture energies were attributable primarily to the unidirectional alignment fibrous Si3 N4 grains. 相似文献
26.
NO
x
reduction with a combination of catalysts, Pd catalyst, NO
x
storage reduction (NSR) catalyst and Cu/ZSM-5 in turn, was investigated to elucidate for the high NO
x
reduction activity of this catalyst combination under oxidative atmosphere with periodic deep rich operation. The catalytic
activity was evaluated using the simulated exhaust gases with periodically fluctuation between oxidative and reductive atmospheres,
and it was found that the NO
x
reduction activity with this catalyst combination was apparently higher than that of the solely accumulation of these individual
activities, which was caused by the additional synergic effect by this combination. The Pd catalyst upstream of the NSR catalyst
improved NO
x
storage ability by NO2 formation under oxidative atmosphere. The stored NO
x
was reduced to NH3 on the NSR catalyst, and the generated NH3 was adsorbed on Cu/ZSM-5 downstream of the NSR catalyst under the reductive atmosphere, and subsequently reacted with NO
x
on the Cu/ZSM-5 under the oxidative atmosphere. 相似文献
27.
Ben Huybrechts Kozo Ishizaiki Masasuke Takata 《Journal of the American Ceramic Society》1994,77(1):286-288
The positive temperature coefficient of resistivity (PTCR) behavior of semiconductive BaTiO3 is well explained by the Heywang model, which predicts the resistivity behavior above the Curie point based on the acceptor state density at the grain boundaries, the charge carrier density, and the energy gap, E s , between the conduction band and the acceptor levels. However, the relationship between these parameters and the production parameters (sintering time, composition, and cooling rate) is not well understood. Recently, the present authors have found that E s can be increased by thorough oxidation. This increase is attributed to a change in the oxidation state of the acceptor. Based on this finding and results from the literature, a phenomenological PTCR model and an accompanying PTCR chart for acceptor–donor-codoped BaTiO3 are proposed to clarify this relationship. The PTCR chart clarifies that acceptor dopant concentrations, oxidation time, and oxygen partial pressure during oxidation or cooling can be optimized simultaneously to obtain optical PTCR properties. 相似文献
28.
Ben Huybrechts Kozo Ishizaki Masasuke Takata 《Journal of the American Ceramic Society》1992,75(3):722-724
Experimental evidence shows that the acceptor-state levels in Sb-doped positive-temperature-coefficient-type BaTiO3 are compensated up to a critical acceptor-state density. Using the slope of the natural logarithm of the resistivity with respect to 1/ T , instead of maximum resistivity as a measure for the acceptor-state density, it is possible to estimate this critical value. The value obtained (4.2 × 1017 m−2 ) is believed to be the first reported estimate based on experimental data. It is in good agreement with the estimate of 6 × 1017 m−2 (first reported by Jonker) obtained from the spontaneous polarization of BaTiO3 . This shows that the ferroelectric behavior of BaTiO3 is indeed a feasible explanation for the low resistivity below the Curie point, as proposed by Jonker. 相似文献
29.
Masashi Wada Satoshi Kitaoka Naoki Kawashima Tatsuya Yamada Yoshiyuki Yasutomi Masatoshi Kawai Hideki Inagaki 《Journal of the American Ceramic Society》2006,89(7):2134-2139
Carbon substrates were coated completely with a molten silicate glass, where the wettability of carbon to glass was improved by infiltration and pyrolysis of perhydropolysilazane. Microstructures of the carbon–glass interface were dependent on P n 2 during coating. Coating at lower P n 2 induced the formation of cristobalite at the carbon–glass interface. When the coating was performed at higher P n 2 , the glass and carbon were strongly adhered, without the formation of cristobalite. Coating at higher P n 2 improved the thermal shock resistance of the glass layer, because crack initiation was not induced by the phase transformation of cristobalite during the cooling process. In the case of coating at higher P n 2 , an oxynitride glass layer was formed at the glass subsurface by dissolution of N2 . A porous glass subsurface layer with uniform spherical micro-pores could be produced by soaking near the glass transition temperature in a steam environment. The porous layer with fine and homogeneous microstructure acts as a thermal shock absorbing layer, so that glass-coated carbon with a porous glass layer has excellent thermal shock resistance in addition to steam oxidation resistance. 相似文献
30.
Yoshitsugu Kosugi Tsutomu Kunieda Naoki Azuma 《Journal of the American Oil Chemists' Society》1994,71(4):445-448
Rice bran oil containing 30–50% free fatty acid was continually converted to an oil containing more than 75% of triacylglycerol
(TG) by means of immobilized lipase. The reaction was carried out at 60°C for 24 h with dehydration and reactant mixing by
dry nitrogen flow under a positive nitrogen atmosphere. Enzymatic TG synthesis with evaporation by heating was not suitable
because of the increasing peroxide value of the oil.
Part of this article was presented at the annual meeting of the Japan Oil Chemists' Society at Sendai, Japan, October, 16,
1990. 相似文献