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71.
Yasumasa?Minemoto Shuji?AdachiEmail author Yuji?Shimada Toshihiro?Nagao Toshio?Iwata Yoshie?Yamauchi-Sato Takaya?Yamamoto Tadashi?Kometani Ryuichi?Matsuno 《Journal of the American Oil Chemists' Society》2003,80(7):675-678
The autoxidation processes of the cis-9,trans-11 (c9,t11) and trans-10,cis-12 (t10,c12) isomers of CLA were separately observed at ca. 0% RH and different temperatures. The t10,c12 CLA oxidized faster than the c9,t11 isomer at all tested temperatures. The first half of the oxidation process of t10,c12 CLA obeyed an autocatalytic-type rate expression, but the latter half followed first-order kinetics. On the other hand,
the entire oxidation process of c9,t11 CLA could be expressed by the autocatalytic-type rate expression. The apparent activation energies and frequency factors
for the autoxidation of the isomers were estimated from the rate constants obtained at various temperatures based on the Arrhenius
equation. The apparent activation energies for the CLA isomers were greater than those for the nonconjugated n−6 and n−3 PUFA
or their esters. However, the enthalpyentropy compensation held during the autoxidation of both the CLA and PUFA. This suggested
that the autoxidation mechanisms for the CLA and PUFA were essentially the same. 相似文献
72.
S. Shimada M. Tanaka H. Kiyono K. J. D. MacKenzie 《Journal of the European Ceramic Society》2001,21(16):2811-2819
An attempt was made to prepare various F-doped β-, O-, X-, and -SiAlONs from a mixture of Si3N4, SiO2, Al2O3, AlN, or Y2O3 using AlF3 or topaz as the fluorine source by HIPing at 1500–1800°C and 150 MPa. The phases were identified and the z, x, and m/n values determined for β-, O-, and -SiAlONs by X-ray diffraction. When AlF3 was used, a single phase ceramic (O-SiAlON) was produced from a mixture of -Si3N4 and SiO2 at 1500°C, with a mixture of O- and β-SiAlONs formed at 1700°C. A mixture of -Si3N4, AlN, and Y2O3 with AlF3 produced β-/Y--SiAlON ceramics at 1730°C. The use of topaz produced the β-SiAlON ceramic with a trace of mullite from a mixture of -Si3N4 and AlN at 1770°C and mixed phase β-/O-SiAlON ceramics from -Si3N4 and SiO2 at 1700°C. Single phase X-SiAlON could not be obtained under the present conditions. The microstructures of the single phase O- and β-SiAlON ceramics and the β-/Y--SiAlON mixture showed the growth of O- and β-SiAlON and Y--SiAlON crystals with hexagonal and/or long rod-like or platy shapes in a matrix of F-containing glassy phase. The compositions of the SiAlON crystals and the glass phase were semi-quantitatively determined by EDX; the total glass phase was estimated by a quantitative Rietveld XRD powder method. The F-doped β-SiAlON ceramics showed better corrosion resistance towards NaCl vapor and lower Vickers hardnesses. 相似文献
73.
Akiko?Kawashima Toshihiro?NagaoEmail author Yomi?Watanabe Takashi?Kobayashi Ikuo?Ikeda Yoshio?Tominaga Yuji?Shimada 《Journal of the American Oil Chemists' Society》2004,81(11):1013-1020
TAG (MLM) with medium-chain FA (MCFA) at the 1,3-positions and long-chain FA (LCFA) at the 2-position, and TAG (LMM) with
LCFA at the 1(3)-position and MCFA at 2,3(1)-positions are a pair of TAG regioisomers. Large-scale preparation of the two
TAG regioisomers was attempted. A commercially available FFA mixture (FFA-CLA) containing 9-cis, 11-trans (9c, 11t)- and 10t,12c-CLA was selected as LCFA, and caprylic acid (C8FA) was selected as MCFA. The MLM isomer was synthesized by acidolysis of acyglycerols (AG) containing two CLA isomers with
C8FA: A mixture of AG-CLA/C8 FA (1∶10, mol/mol) and 4 wt% immobilized Rhizomucor miehei lipase was agitated at 30°C for 72 h. The ratio of MLM to total AG was 51.1 wt%. Meanwhile, LMM isomer was synthesized by
acidolysis of tricaprylin with FFA-CLA: A mixture of tricaprylin/FFA-CLA (1∶2, mol/mol) and 4 wt% immobilized R. miehei lipase was agitated at 30°C for 24 h. The ratio of LMM to total AG was 51.8 wt%. MLM and LMM were purified from 1,968 and
813 g reaction mixtures by stepwise short-path distillation, respectively. Consequently, MLM was purified to 92.3% with 49.1%
recovery, and LMM was purified to 93.2% with 52.3% recovery. Regiospecific analyses of MLM and LMM indicated that the 2-positions
of MLM and LMM were 95.1 mol% LCFA and 98.3 mol% C8 FA, respectively. The results showed that a process comprising lipase reaction and short-path distillation is effective for
large-scale preparation of high-purity regiospecific TAG isomers. 相似文献
74.
Manabu Tsuburaya 《Polymer》2004,45(3):1027-1032
We found that amorphous polycarbonate (PC) can be crystallized in several minutes by blending poly(ethylene oxide) (PEO). When the blends were annealed in the two-phase region below the upper critical solution temperature, highly interconnected two-phase structure characteristic of the spinodal decomposition was developed and then the crystallization occurred in the PC-rich phase during the spinodal decomposition. As the molecular weight of PEO decreased, the crystallization rate decreased and the crystallizable temperature became narrower in spite of the acceleration of the polymeric segmental motion. These results suggest that the crystallization of the PC is not induced by the acceleration of the polymeric segmental motion, but by the up-hill diffusion of the liquid-liquid phase separation via spinodal decomposition. Owing to the competitive progress of the crystallization and the spinodal decomposition, the melting peak of the PC crystallites shifted to lower temperature with increasing annealing temperature. 相似文献
75.
The design of an ultraprecision displacement sensor with sub-nanometre resolution is proposed for the use of ultraprecision technologies. The sensor is based on the highly sensitive detection of power change at a specific point in light reflected from an object surface when the surface is subject to a small displacement. The sensor consists of a single light source, the reflective object and reference surfaces, optical fibre bundles for tranmission of the illuminating and the reflected light, and the photodiode set-up. In operation, the object and the reference surfaces are illuminated by light transmitted through the optical fibre bundle from the single light source. The reflected light from both surfaces is then transmitted through the optical fibre bundle to two individual but equivalent photodiodes. By using a differential amplifier, the diodes give a highly sensitive displacement signal which is included in the total signal of the reflected light. The sensor proposed has some distinctive features in its performance, such as non-contact measurement, a high resolution of 0.5 nm, a wide working range of about 30 μm within 5% linearity, and the sufficient stability of 1 nm in 20 s for specific research purposes. 相似文献
76.
Manabu Gotoh 《Metals and Materials International》1998,4(4):628-639
Various types of behavior due to plastic instability under uniaxial tension and compression are numerically investigated regarding
sheet materials, plane strain blocks, and cylindrical bars and hollow cylinders. The code GOLDA for analysis of large elastic-plastic
deformation previously developed by the author is used, which is one of quasi-static explicit FEM programs. Both of diffuse
type and localized type of instability are concerned with. The role of vertex-hardening in plastic instability is payed attention,
by using the J2G (J2-Gotoh’s corner theory) as the plasticity constitutive equation, which was proposed previously by the
author and is a kind of vertex-hardening theory. Following results are mainly derived. 1) In plane strain tension, shear-type
strain localization is realized by the use of J2G, but not by the conventional J2F (J2-flow theory). In axisymmetric tension
of a cylindrical solid bar, however, such strain localization would never appear even by J2G, as expected by the experiment.
2) In axisymmetric tension of a hollow cylinder under the condition of no contractlion of its bore (therefore, in almost plane
strain state with no circumferential strain), it is found that shear-type strain localization could occur. This is realized
again by the use of J2G, whereas J2F never allows such strain localization. 3) In compression under the embedded edges condition,
it is found that a sheet with initial aspect ratio of 2:1 (in height:breadth) yields double barreling, whereas a plane strain
block yields double barreling at the initial aspect ratio of 3:1, not at 2:1 though expected from the conventional slip-line
theory. As for a cylindrical solid bar, double barreling appears for the initial aspect ratio of 2:1 but only for higher n-vaiue
(the strain hardening exponent), say n=0.5. 4) As for barreling mode, when thick-walled axisymmetric tubes with the initial
ratio of thickness to inner diameter 1/5 to 1/3 are compressed axially, corresponding to the initial aspect ratios of 3:1,
2:1 and 1:1, triple barreling, double barreling and single barreling appear, respectively. 5) It is found that thin-walled
tubes buckle in a progressive periodic mode with almost stationary compressive load under axial compression. Thus it can be
used as a simplified model for buckling of more complex structures such as the honeycomb. 相似文献
77.
Koji Fushimi Takatoshi Shimada Hiroki Habazaki Hidetaka Konno Masahiro Seo 《Electrochimica acta》2011,(4):1773
Depassivation–repassivation of iron surfaces in boric–borate solutions were investigated by using the micro-indentation test. A pair of current peaks due to repair of the passive film following rupture of the film were observed during a series of indenter drives, i.e., loading and unloading of the indenter. The shape of the current peak depended on environmental conditions (conductivity and pH of the solution) and substrate conditions (mechanical processing history, alloyed element) as well as indentation conditions (repetition, maximum depth, and maximum load). Plastic deformation of the surface was accompanied by surface depassivation, while no depassivation occurred during the elastic deformation, indicating that the passive film on iron has a ductile property. The solution conditions did not affect the scale of depassivation but affected the rate of repassivation. Dislocations in the substrate made surface depassivation difficult but enhanced reactivity during the repassivation. The test also revealed that type-312L stainless steel has high corrosion resistance in a concentrated NaCl solution. 相似文献
78.
79.
Manabu Nishijima Irina D. Gocheva Shigeto Okada Takayuki Doi Jun-ichi Yamaki Tetsuaki Nishida 《Journal of power sources》2009,190(2):558-562
Fluorine compounds have high discharge voltage due to its highly ionic metal-ligand bonds. In them, perovskite-type metal trifluorides with corner sharing matrix have large bottlenecks of diffusion pathways for intercalants. Iron trifluoride composites (FeF3-C) prepared by planetary ball milling with carbon showed reversible charge/discharge behavior not only for Li, but also for Na anodes. X-ray diffraction and 57Fe Mössbauer spectroscopy were applied to characterize the electrochemical properties of FeF3 vs. Li and Na anodes. The cathode performances of the other commercially available transition metal trifluorides such as MF3 (M = Ti, V, Mn, Co) have been also investigated. 相似文献
80.
Takanori Isobe Taku Takaku Tadayuki Kitahara Hideo Sumitani Ryuichi Shimada 《Electrical Engineering in Japan》2009,169(4):65-74
This paper proposes a power supply suitable for driving linear induction motors. The power supply consists of a voltage source inverter (VSI) and a magnetic energy recovery switch (MERS). Circuit configuration and operation principles of the power supply are described. Power factor correction by MERS can increase the output power. Technical advantages of using MERS compared with increasing the rated voltage of VSI are discussed. Some experiments with a linear induction motor were conducted. The results confirm that MERS can reduce the capacity of the VSI or increase the output with the same VSI capacity. The number of devices and magnitude of losses are evaluated on a large‐scale drive system. A half‐bridge type of MERS is provided and discussed. The half‐bridge MERS mitigates disadvantages of using MERS. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(4): 65–74, 2009; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.20832 相似文献