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991.
Crystalline/crystalline binary blend films of microbial polyesters composed of poly[(R)-3-hydroxybutyrate-co-(R)-3hydroxyhexanoate] (P(3HB-co-3HH)) and poly[(R)-3-hydroxybutyrate] (P(3HB)) that exhibit a morphological change are prepared by solvent casting. Differential scanning calorimetry measurements indicate that P(3HB-co-3HH) and P(3HB) are miscible for all blend ratios because a single glass transition temperature is observed. Polarization optical microscopy is used to investigate the transition of spherulite morphology and measure the radial growth rate of spherulites in the blend films. P(3HB-co-3HH) and P(3HB) contain positive spherulites, whereas in the binary blends, spherulite morphology changes from positive to negative. This change is related to the different growth rates of P(3HB-co-3HH) and P(3HB) lamellar crystals. Partial enzymatic degradation of the film surfaces reveals that the lamellar crystals of negative spherulites are oriented both perpendicular and parallel to the radial direction of spherulites. A new growth mechanism for spherulites in crystalline/crystalline blends is constructed from the results obtained for the blend films. 相似文献
992.
993.
994.
The estimation problem for chaos models defined by deterministic differential equations is discussed, and the important role of the maximum likelihood method in the inferential study of chaos models is highlighted. The usefulness of the likelihood function in the inferential study of chaos is confirmed with numerical examples from the Lorenz chaos model and the Rikitake two disk dynamo chaos model. 相似文献
995.
Shinya Ohtsuka Masaki Koumura Kazuhisa Eguchi Masayuki Hikita 《Electrical Engineering in Japan》2005,151(3):32-40
This paper deals with partial discharge (PD) time‐sequential properties of SF6/N2/CO2 ternary gas mixture as well as SF6 and SF6/N2 gas mixture under AC and positive DC voltage applications. The measurements were carried out by changing the gas pressure up to 0.6 MPa and applied voltage with the N‐shape characteristics of breakdown voltage versus gas pressure for each tested gas considered. We obtained experimental results of the gas pressure dependence of maximum peak value of PD current pulse as well as the relationship between the time interval of PD pulses and the peak value of PD pulse. We discuss the mechanism of increase in breakdown voltage by adding CO2 into SF6/N2 gas mixtures in terms of change of PD type from streamer to leader discharge. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 151(3): 32–40, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20073 相似文献
996.
997.
Higashi H. Masaki S. Kibune M. Matsubara S. Chiba T. Doi Y. Yamaguchi H. Takauchi H. Ishida H. Gotoh K. Tamura H. 《Solid-State Circuits, IEEE Journal of》2005,40(4):978-985
A 5-6.4 Gb/s transceiver, consisting of a parallel 12-channel transmitter (Tx), 12-channel receiver (Rx), clock generators based on LC-VCO phase-locked loops (PLLs), and a clock recovery unit, was developed. The Tx has a five-tap pre-emphasis filter, and the Rx has an equalizer with an intersymbol interference (ISI) monitor. Monitoring the ISI enables fine adjustment of loss compensation. The pre-emphasis filter in the Tx and the equalizer in the Rx compensate for transmission losses of up to 20 dB at 6.4 Gb/s, respectively. Both the Tx and Rx channels, including the PLLs, are 3.92 mm/sup 2/ in area. The transmitter dissipates 150 mW/channel at 6.4 Gb/s when compensating for a loss of 20 dB, and the receiver 90 mW/channel when compensating for the same loss. 相似文献
998.
999.
Kenji Ishihara Masakazu Murata Masaki Kaneniwa Hiroaki Saito Kazuki Shinohara Mari Maeda-Yamamoto Ken-ichi Kawasaki Tooru Ooizumi 《Lipids》1998,33(11):1107-1114
6,9,12,15,18,21-Tetracosahexaenoic acid (24∶6n−3) was isolated from a brittle star, Ophiura sarsi Lütken, at>95% purity to evaluate its physiological functions. The effects of 24∶6n−3 on the production of leukotriene (LT)-related
compounds such as LTB4, LTC4 and 5-hydroxyeicosatetraenoic acid, and the accumulation and release of histamine in an MC/9 mouse mast cell line were studied.
We found that 24∶6n−3 could inhibit the antigen-stimulated production of LT-related compounds as well as other n−3 polyunsaturated
fatty acids (PUFA) such as eicosapentaenoic acid (20∶5n−3) and docosahexaenoic acid (22∶6n−3), which are major n−3 PUFA in
fish oils; 24∶6n−3 was also shown to reduce the histamine content in MC/9 cells at 25 μM (27% reduction from the control),
and the effect was diminished with increase of the fatty acid concentration (up to 100 μM). These two n−3 PUFA, 20∶5n−3 and
22∶6n−3, also reduced the histamine content (16 and 20% reduction at 25 μM, respectively), whereas arachidonic acid (20∶4n−6)
increased it (18% increase at 25 μM). Spontaneous- and antigen-induced release of histamine was not influenced with these
PUFA (at 25 μM). Ionophore-stimulated release of histamine was suppressed by the PUFA (13,9,15, and 11% reduction with 20∶4n−6,
20∶5n−3, 22∶6n−3, and 24∶6n−3, respectively). The patterns of the effects of 24∶6n−3 on the synthesis of eicosanoids and histamine
content were more similar to those of 22∶6n−3 than 20∶5n−3. From these results, 24∶6n−3 can be expected to have anti-inflammatory
activity and antiallergic activities similar to those of 22∶6n−3. 相似文献
1000.
Daxiang Huang Yuichi Ikuhara Masaki Narisawa Kiyohito Okamura 《Journal of the American Ceramic Society》1998,81(12):3173-3176
Boron-doped and nondoped ultrafine β-silicon carbide (β-SiC) powders were synthesized via the carbothermal reduction of SiC precursors at temperatures of 1773–1973 K. Although the reaction rate of carbothermal reduction was generally higher when a boron-doped precursor was used, the reaction rate for the boron-doped precursor was reduced considerably at 1873 K. For boron-doped and nondoped precursors, the reaction rates were almost the same. Powder characterization via transmission electron microscopy indicated that the suppression of the reaction rate for boron-doped precursor at 1873 K was due to the formation of a special coexistent system with two types of particle agglomerates. As expected, boron doping inhibited the particle growth in the synthesis of SiC powder. 相似文献