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991.
R. Hasegawa I. Sakata H. Yanagihara B. Johansson A. Omrane M. Aldén 《Applied physics. B, Lasers and optics》2007,88(2):291-296
A new technique based on phosphor thermometry for measurements of two-dimensional gas-phase temperature, was examined as a
new laser diagnostic. Calibration of Dy:YAG phosphor was carried out on the surface of a solid. The data were applicable for
gas thermometry since the validation of the line intensity ratios method, showed good agreement with both the lifetime method
and thermocouple data in a steady gas flow. Single-shot phosphor thermometry was examined in turbulent combustion in an engine.
A reasonable temperature deviation and agreement with calculated data to within 5% precision was achieved in the ignition
process of a compression ignition engine. Influencing factors such as chemical luminescence and intrusion into the combustion
have also been discussed.
PACS 07.20.Dt; 33.50.Dq; 42.62.-b 相似文献
992.
Simoni Maria Gheno Haroldo Lhou Hasegawa Pedro Iris Paulin Filho 《Journal of Physics and Chemistry of Solids》2006,67(11):2253-2256
Barium titanate is the main constituent of PTC materials and their electric properties are sensitive to microstructure and defects, in atomic scale, that are significantly affected by processing parameters. The microstructure of barium titanate doped with yttrium was investigated using topographic images obtained by AFM in contact mode. The AFM images of barium titanate doped with yttrium showed the effect of large grains with double twins at different (1 1 1) planes. 相似文献
993.
Tsutomu Takeichi Min Zuo Masatoshi Hasegawa 《Journal of Polymer Science.Polymer Physics》2001,39(23):3011-3019
Poly(amide acid) labeled with perylenetetracarboxydiimide (PEDI) was prepared from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA), p‐phenylenediamine (PDA), and diamino‐PEDI. Poly(amide acid) was then reacted with sodium hydride and various kinds of alkyl iodides for transformation into various poly(amide ester)s. The cast films were imidized while fixed on glass substrates to give BPDA/PDA polyimide films. The degree of in‐plane molecular orientation (f) of the polyimides and their precursors, poly(amide acid) and poly(amide ester)s, were determined via measurements of the visible dichroic absorption at an incidence angle for a rodlike dye (PEDI) bound to the main chain. All precursor films showed relatively low degrees of in‐plane orientation. After imidization of the precursors fixed on glasses, however, striking spontaneous in‐plane orientation behavior was observed. The f value for polyimide film from a poly(amide acid) precursor was as high as 0.7–0.8. The f value for polyimide film from a methyl ester precursor, however, was lowered to 0.4–0.5, but it increased with the increasing size of the alkyl groups. Good correlations of the in‐plane orientation of the polyimide films with the tensile modulus of the films and the in‐plane orientation of the graphitized films were observed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 3011–3019, 2001 相似文献
994.
Essam Mohamed Sharshira Satoru Shimada Mutsuo Okamura Eietsu Hasegawa Takaaki Horaguchi 《Journal of heterocyclic chemistry》1996,33(6):1797-1805
Photocyclization reactions were carried out on 2-alkoxybenzophenones 1a-h and ethyl 2-benzoylphenoxyacetates 2a -e in acetonitrile. Irradiation of 1a-h gave dihydrobenzofuranols 4a-h in 68–84% yields. Similarly, irradiation of 2a-e afforded dihydrobenzofuranols 8a-e in 72–75% yields. Ethyl acrylates 9b-c were also produced in 6–8% yields from photoreactions of 2b-c . Substituent effects on cyclization of 1,5-biradical intermediates and reaction pathways are discussed. Benzophenones are useful compounds to prepare dihydrobenzofuranols by photocyclization. 相似文献
995.
Takaaki Horaguchi Chikara Tsukada Eietsu Hasegawa Takahachi Shimizu Tsuneo Suzuki Kiyoshi Tanemura 《Journal of heterocyclic chemistry》1991,28(5):1261-1272
Photocyclization reactions were carried out on 2-alkoxybenzaldehydes 1a-f , 2′-alkoxyacetophenones 2a-h , 2-formylphenoxyacetic acids 1i-l and 2-acetylphenoxyacetic acids 2i-m . Irradiation of 1a-f and 2a-h in acetonitrile gave the corresponding dihydrobenzofuranols 3, 5 and dihydroisobenzofuranols 4, 6 . Using carboxylic acids 1i-1, 2i-m as starting materials, decarboxylation occurred immediately to give the corresponding ethers 1a-d, 2a-e . Further irradiation of the solution afforded dihydrobenzofuranols 3, 5 and dihydroisobenzofuranols 4, 6 . Substituent effects on photocyclization and reaction pathways are discussed. 相似文献
996.
Katsuro Oda Takayo Hasegawa Yasuhiro Fujimori Kouji Sugihara Seiiti Kato Hiromitsu Ino 《Hyperfine Interactions》1992,70(1-4):1175-1178
Mossbauer spectra of57Fe have been measured for Bi2Sr2Can-1(Cu, Fe)nOy (n=1,2,3) oxide superconductors. Each spectrum was decomposed to a single set or two sets of double peaks. The assignment
of these peaks to the specific sites for the iron atoms are discussed. The 4 fold planar sites of Cu2O plane are preferentially substituted by Fe atoms. 相似文献
997.
In order to investigate the effectiveness of a novel oxide-free surface passivation approach for InP, using an ultrathin silicon interface control layer (Si ICL), gated photoluminescence characteristics of the Si3N4/Si ICL/n-InP metal–semiconductor–insulator (MIS) structure were studied at room temperature. As compared with gated PL spectra of Si3N4/n-InP MIS without Si ICL, PL intensities of the sample with Si ICL were much more strongly modulated by the gate voltage. The interface state density distribution was estimated by an optical analog of the Terman’s C–V analysis and a good agreement with the C–V analysis was obtained. The result indicates complete removal of Fermi level pinning over the entire bandgap in the novel oxide-free MIS structure. 相似文献
998.
The effects of nitrogen addition on methane-based ECR plasma etching of GaN were studied. The etch rate 30 nm/min and r.m.s. roughness 2.6 nm were obtained when the GaN sample was etched by a methane-based gas mixture without N2. The addition of N2 gas resulted in a decrease of etch rate and a smoother etched surface. The r.m.s. roughness became less than 0.4 nm even only 1.5 sccm N2 gas was added to the mixture. In situ XPS measurements showed that, without N2, heavy N-depletion took place on the etched surface, resulting in appearance of Ga metal on the surface. In contrast, the loss of N was compensated when the N2 gas was added, and the etched surface approached the stoichiometric one with the increase of N2 gas flow. This suppression of preferential loss of N was considered to be the main reason that improved the etched surface morphology. 相似文献
999.
The reaction of the Si8O208? silicate anion with X(CH3)2SiCl (X?H or CH3) has been studied to develop a cost‐effective procedure for synthesizing Si8O20[Si(CH3)2X]8 in high yield. Use of hexane as solvent and adjustment of the reaction temperature to ca 20 °C were found to be effective in promoting the reaction, by which Si8O20[Si(CH3)2X]8 could be produced in good yield employing 24 mol of X(CH3)2SiCl per mole of Si8O208?. It was also demonstrated that the yield of Si8O20[Si(CH3)2X]8 depends on the amount of solvent, suggesting that the amount is an important factor when scaling up the reaction to produce a large quantity of Si8O20[Si(CH3)2X]8. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
1000.
Akihiro Suzuki Takashi Kawada Toshinori Hasegawa 《Journal of Polymer Science.Polymer Physics》2001,39(14):1629-1637
Poly(ethylene‐2,6‐naphthalate) fibers were zone‐drawn under a critical necking tension (σc) defined as the minimum tension needed to generate a necking at a given drawing temperature (Td). In the zone drawing under σc, the neck was observed from 110 to 160 °C. The superstructure in a neck zone induced at each Td was studied. The σc value decreased exponentially with increasing Td and dropped to a low level at a higher Td. The draw ratio increased rapidly with Td increasing above 90 °C, but the birefringence and degree of crystallinity decreased gradually. To study the molecular orientation in the neck zone, we measured a dichroic ratio (A‖/A?) of a C? O band at 1256 cm?1 along a drawing direction in the neck zone with a Fourier transform infrared microscope. A‖/A? at Td = 110 °C increased rapidly in the narrow neck zone, and that at Td = 140 °C increased in the edge of the wide neck zone. Wide‐angle X‐ray diffraction patterns of the fibers obtained at Td = 130 °C and lower showed three reflections due to an α form, but those at Td = 140 and 150 °C had reflections due to the α form and a β form. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1629–1637, 2001 相似文献