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排序方式: 共有437条查询结果,搜索用时 15 毫秒
111.
Guosheng Xu Tomohiko Yamakami Tomohiro Yamaguchi Morinobu Endo Seiichi Taruta Isao Kubo 《International Journal of Applied Ceramic Technology》2014,11(2):280-288
To enhance the fracture toughness of silicon carbide (SiC) ceramics and prevent the generation of cracks and chippings in the SiC ceramics during machining process, carbon nanofibres (CNFs) were compounded with SiC. The densification and microstructure development of the CNFs/SiC composites pressureless sintered in Ar atmosphere were investigated. The fracture toughness of SiC ceramics was enhanced by the addition of 1–3 wt% CNFs, which resulted from the pullout and/or bridging effect of CNFs bonded much more closely with SiC. The addition of 3 wt% CNFs prevented the chippings from generating in the composite during precision machining process. 相似文献
112.
Seiichi Taruta Mutsumi Matsuki Hiromasa Nishikiori Tomohiko Yamakami Tomohiro Yamaguchi Kunio Kitajima 《Ceramics International》2010
Eu-doped transparent mica glass–ceramics were prepared, the influence of Eu-doping on the crystallization of the parent glasses was investigated and the luminescent properties of the parent glasses and the glass–ceramics were estimated. A small additive amount of Eu element was very effective in preparing transparent mica glass–ceramics. However, the excess addition led to the coarsening of phase separation in the glass phase and the separation of unidentified crystal phases and β-eucryptite during heating of the parent glasses, which caused white opaque at lower heating temperatures. When mica crystals were separated, Eu ions entered the interlayers of mica crystals. The observed emission and excitation spectra showed that parts of Eu3+ ions which were added as Eu2O3 were reduced to Eu2+ ions during melting of the starting materials and heating the parent glasses in air and the energy transfer from Eu2+ to Eu3+ ions occurred. 相似文献
113.
Conventional multi-zonal ventilation measurement methods by multiple types of perfluorocarbon tracers use a number of different gases equal to the number of zones (n). The possible n×n+n airflows are estimated from the mass balance of the gases and the airflow balance. However, some airflows may not occur because of inter-zonal geometry, and the introduction of unnecessary, unknown parameters can impair the accuracy of the estimation. Also, various error factors often yield an irrational negative airflow rate. Conventional methods are insufficient for the evaluation of error. This study describes a way of using the least-squares technique to improve the precision of estimation and to evaluate reliability. From the equations’ residual, the error variance–covariance matrix Λq of the estimated airflow rate error is deduced. In addition, the coefficient of determinant using the residual sum of squares and total variation is introduced. Furthermore, the error matrix mΛq from the measurement errors in the gas concentration and gas emission rate is deduced. The discrepancy ratio of the model premises is defined by dividing the diagonal elements of the former by those of the latter. Moreover, the index of irrationality of the estimated negative airflow rate is defined, based on the different results of the three estimation methods. Some numerical experiments are also carried out to verify the flow rate estimation and the reliability evaluation theory. 相似文献
114.
Tomohiro Yamaguchi Kazuya Ikuta Seiichi Taruta Kunio Kitajima 《Materials Science and Engineering: B》2012,177(7):524-527
Na-taeniolite (NaMg2LiSi4O10F2) mica crystals were synthesized from nonstoichiometric raw batches containing NaCl as a flux, in order to control the morphology of mica crystals. Swellable Na-taeniolite was obtainable from both stoichiometric and nonstoichiometric batches although small amounts of different products were coprecipitated, depending on the composition of the raw batches. Samples obtained from raw batches containing ≤1 mol NaCl consisted of a single-phase swellable mica. The addition of a small amount of NaCl was effective in controlling the morphology of the mica crystals. Raw batches containing 1 mol NaCl yielded mica crystals having a hexagonal, plate-like morphology with a larger aspect ratio. Alumina-pillared micas prepared from host micas thus obtained from raw batches containing NaCl had larger specific surface areas than those obtained from stoichiometric batches. This suggests that the swellability of mica crystals is also affected by the addition of NaCl. 相似文献
115.
Biodegradability of Plastics 总被引:1,自引:0,他引:1
Yutaka Tokiwa Buenaventurada P. Calabia Charles U. Ugwu Seiichi Aiba 《International journal of molecular sciences》2009,10(9):3722-3742
Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed. 相似文献
116.
Analysis of molecular dynamics of colloidal particles in transported dilute samples by self-mixing laser Doppler velocimetry 总被引:1,自引:0,他引:1
Colloidal particles in a liquid medium are transported with constant velocity, and dynamic light scattering experiments are performed on the samples by self-mixing laser Doppler velocimetry. The power spectrum of the modulated wave induced by the motion of the colloidal particles cannot be described by the well-known formula for flowing Brownian motion systems, i.e., a combination of Doppler shift, diffusion, and translation. Rather, the power spectrum was found to be described by the q-Gaussian distribution function. The molecular mechanism resulting in this anomalous line shape of the power spectrum is attributed to the anomalous molecular dynamics of colloidal particles in transported dilute samples, which satisfy a nonlinear Langevin equation. 相似文献
117.
Crosslinking junctions of vulcanized natural rubber were analyzed by solid-state NMR spectroscopy equipped with a field-gradient high speed magic angle spinning probe. Resolution of 1H and 13C NMR spectra and correlations between 1H and 13C of the vulcanized natural rubber were investigated by one- and two-dimensional measurements, including inverse correlation measurements. The number of substitution of the carbon atom at the crosslinking junctions was determined by solid-state NMR spectroscopy. 相似文献
118.
Evaluation of Models for Spinach Respiratory Metabolism Under Low Oxygen Atmospheres 总被引:2,自引:0,他引:2
Soraya Saenmuang Muhammad Imran Al-Haq Himani Chamila Samarakoon Yoshio Makino Yoshinori Kawagoe Seiichi Oshita 《Food and Bioprocess Technology》2012,5(5):1950-1962
Anaerobic respiration is a major problem that causes the deterioration of fresh produce packaged under low O2 atmospheres. The problem becomes more severe and causes high losses in the packages handling at ambient conditions, especially
in developing countries. In designing modified atmosphere packaging, the risk of anaerobic development greatly depends upon
the accuracy of respiration rate prediction; therefore, the respiration rate model for a particular produce has to be identified.
In this study, different atmospheric storage conditions in a closed system were realized to examine the adaptability of respiration
rate models for spinach storage under low O2 at an expected ambient temperature of 25 °C. Six models were applied and it was found that, for aerobic conditions, the respiration
rate could be described with a constant respiratory quotient by three models, viz., (a) Michaelis–Menten model without inhibition,
(b) Michaelis–Menten model with uncompetitive inhibition, and (c) Langmuir adsorption model, whereas three other models, viz.
(d) Michaelis–Menten model with competitive inhibition, (e) Michaelis–Menten model with noncompetitive inhibition, and (f)
Michaelis–Menten with mixed inhibition could not be fitted. Among the three successful models, the Michaelis–Menten with uncompetitive
inhibition was found to be the most suitable model for practical applications in developing countries where cold-chain systems
are lacking. This model can be applied for the prediction of gas composition and optimize the packages, particularly to ensure
the aerobic respiration. 相似文献
119.
Ishihara Ken Katayama Seiichi Watanabe Takeji Seto Makoto Matsuyama Isamu 《Industry Applications, IEEE Transactions on》1985,(1):147-153
Recently, adjustable-speed ac drive systems have been employed successfully for blowers, pumps, table rollers, etc., in steel plants instead of the more conventional dc drives. In processing lines many drives require speed and tension control. To confirm the suitability of an ac drive for tension control, the tension reel of an existing pilot processing line has been equipped with an adjustable-speed ac drive. An ac drive system for tension reel control, its characteristics, and performance are described and compared with a dc tension control. 相似文献
120.
A new method for fast extraction of straight line and circle is proposed in this study. The method utilizes the Polytope method
which is one of minimization algorithms. For the extraction of figures, one-dimensional histogram is used. Basically, main
algorithm of the extraction of straight line is the same as those of circle and ellipse. Only the definition of histogram
and the evaluation function are changed according as figures. By the comparison with Hough transform, it is understood that
the using of memory space is very small and processing time is very short.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献