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101.
Masaki Okazaki Teruaki Hayakawa Mitsuru Ueda Kazuhiko Takeuchi Michihiko Asai 《Journal of polymer science. Part A, Polymer chemistry》2001,39(1):78-85
A convenient method for the synthesis of polyester‐containing amino substitutes on the aromatic rings of the backbone has been developed. This polyester was prepared by chemoselective polyesterification of isophthalic acid with bisphenol having an amino group in the presence of the condensing agent diphenyl(2,3‐dihydro‐2‐thioxo‐3‐benzoxazolyl)phosphonate ( 1 ) and 1,5‐diazabicyclo[4,3,0]‐5‐nonene as a base. The model reactions were carried out in detail to elucidate appropriate conditions of chemoselective polyesterification. Direct polycondensation of isopthalic acid with 4,4′‐[1‐(4‐aminophenyl)ethylidene]bisphenol proceeded smoothly under mild conditions and produced the desired polyester with a number average molecular weight of 11,000 and Mw/Mn of 2.22. The polymer obtained was characterized by IR, 1H, and 13C NMR spectroscopies. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 78–85, 2001 相似文献
102.
M. Asai I. Endo M. Harada S. Kasai K. Niki Y. Sumi S. Kato K. Maruyama Y. Murata M. Muto K. Yoshida K. Iwatani H. Hasai H. Ito T. Maki C. Rangacharyulu H. Shimizu Y. Wada 《Zeitschrift für Physik A Hadrons and Nuclei》1992,344(3):335-344
The reaction γ+d → π++π? +p + n has been measured in a kinematically complete way at incident photon energies from 570 to 850 MeV in steps of 40 MeV. From detailed comparison of measured data with results of event simulations, it is concluded that three different mechanisms, the quasi-free, double-delta and phase space productions, contribute to the reaction. Each of the cross sections corresponding to these mechanisms is determined separately. 相似文献
103.
C. C. Hsu P. H. Geil Hideki Miyaji Kenjiro Asai 《Journal of Polymer Science.Polymer Physics》1986,24(10):2379-2401
Glassy isotactic propylene (PP) films of thickness up to 0.3 mm were obtained by an ultraquenching technique. The structure and properties of the as-quenched and subsequently crystallized samples were characterized by various techniques. Electron microscopy indicates the glass has no structure larger than 25 Å. X-ray diffraction shows PP crystallizes from the glass into a smectic structure at ca. ?20°C and then transforms to monoclinic microcrystals at ca. 40°C; a nodular structure (80 to 100 Å in diameter) was observed on the surface. The transformation temperature increases with the film thickness. Annealing above the α-relaxation temperature results in an increase in the nodule size. A correspondence was found between the diameter of the nodules observed on the surface and long spacings obtained by small-angle X-ray scattering from the bulk. Dynamic mechanical spectra show the presence of two relaxation-like peaks at ca. ?10°C and 10°C for the as-ultraquenched samples. X-ray scattering, differential scanning calorimetry (DSC), and torsion pendulum measurements show PP crystallizes from the glass at a temperature, depending on the rate of heating, that corresponds to the lower relaxation peak temperature. 相似文献
104.
Sekine Y Urasaki K Asai S Matsukata M Kikuchi E Kado S 《Chemical communications (Cambridge, England)》2005,(1):78-79
We demonstrated that non-catalytic ethanol steam reforming proceeds efficiently and selectively without coking at the conditions of room temperature and atmospheric pressure using low-energy pulsed (LEP) discharge in combination with carbon fiber electrodes. 相似文献
105.
M. Asai M. Sakama K. Tsukada S. Ichikawa H. Haba I. Nishinaka Y. Nagame S. Goto Y. Kojima Y. Oura H. Nakahara M. Shibata K. Kawade 《The European Physical Journal A - Hadrons and Nuclei》2004,22(3):411-416
EC and decays of 235Am have been studied using a gas-jet coupled on-line isotope separator. Excited states in 235Pu have been established for the first time by means of -ray spectroscopy following the EC decay of 235Am. The deduced log ft value suggests that the ground state of 235Am should have the 5/2-[523] configuration. The - coincidence result has revealed that the 5/2-[523] state in 231Np populated by the favored transition of 235Am is located at < 15 keV, which allows us to precisely determine the Q value of 235Am. 相似文献
106.
M. Asai K. Tsukada S. Ichikawa M. Sakama H. Haba Y. Nagame I. Nishinaka K. Akiyama A. Toyoshima T. Kaneko Y. Oura Y. Kojima M. Shibata 《The European Physical Journal A - Hadrons and Nuclei》2003,16(1):17-19
A new neutron-deficient berkelium isotope 241Bk produced in the 239Pu(6Li, 4n) reaction has been identified using a gas-jet coupled on-line isotope separator. Cm K and L X-rays associated with the EC decay of 241Bk were observed in the mass-241 fraction, and three γ transitions were attributed to the EC decay of 241Bk through X-γ coincidences. The half-life of 241Bk was determined to be 4.6±0.4 min which is 1/2-1/4 of that of theoretical predictions. The half-life value and the observed
γ transitions can be consistently explained as a consequence of the allowed EC transition of π7/2+[633] → ν7/2+[624].
Received: 14 October 2002 / Accepted: 6 November 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: asai@tandem.tokai.jaeri.go.jp
Communicated by J. ?yst? 相似文献
107.
H.?IimuraEmail author M.?Asai S.?Ichikawa J.?Katakura M.?Magara A.?Osa M.?Oshima N.?Shinohara H.?Yamamoto 《The European Physical Journal A - Hadrons and Nuclei》2005,23(1):33-39
The low-lying levels in 127La have been studied through the -decay of 127Ce ( T1/2 = 29s) produced by bombarding a natMo target with a 185-MeV 35Cl beam. Reaction products were on-line mass-separated, and -ray singles and - coincidence measurements were performed. Conversion electrons were also measured and multipolarities of transitions have been derived. The half-life of the 210.9-keV level was determined to be (1.9±0.3)ns by the - delayed coincidence technique. The level scheme obtained has been compared with calculations based on the Nilsson model. 相似文献
108.
T. Maruyama D. Kaji T. Kaneko S. Goto K. Tsukada H. Haba M. Asai S. Ichikawa Y. Nagame H. Kudo 《Journal of Radioanalytical and Nuclear Chemistry》2003,255(2):253-256
Rapid chemical separation of berkelium is essential in order to measure the unknown isotope 252Bk. An anion exchange system of mineral acid and methanol was examined. An elution curve of Bk was obtained using 250Bk produced by the 248Cm+18O system and the 251Bk activity could be measured in the preliminary experiments. The whole chemical separation was completed within 30 minutes. 相似文献
109.
M. Asai J. L. Bailly H. B?ttcher F. Bruyant C. Caso Y. Chiba H. Dibon B. Epp A. Ferrando F. Fontanelli S. N. Ganguli T. Gémesy R. Hamatsu P. Hidas T. Hirose J. Hrubec T. Kageya N. Khalatyan E. Kistenev I. Kita S. Kitamura V. Kubik J. MacNaughton M. Markytan S. Matsumoto I. S. Mittra L. Montanet G. Neuhofer G. Pinter P. Porth T. Rodrigo J. Singh S. Squarcia K. Takahashi R. Tanaka L. A. Tikhonova U. Trevisan R. Wischnewski T. Yamagata S. A. Zotkin NA EHS-RCBC Collaboration 《Zeitschrift fur Physik C Particles and Fields》1990,46(4):593-598
Properties of proton diffractive dissociation have been investigated for four-prong final states in proton-proton reactions at 360 GeV/c, in particular forpp→ppπ +π? mπ 0(m=0,1,2). Mass distributions and decay angular distributions are given. The decay of the diffractive system is seen to be very anisotropic, and largep T is suppressed at higher masses. It is found that the “pomeron” couples with a single valence quark of the incident proton, but indications for a diquark-pomeron coupling are also found. Similarities with fragmentation in lepton-hadron deep inelastic scattering are underlined. 相似文献
110.
Tsutomu UmebayashiTetsuya Yamaki Hisayoshi ItohKeisuke Asai 《Journal of Physics and Chemistry of Solids》2002,63(10):1909-1920
The electronic structures of titanium dioxide (TiO2) doped with 3d transition metals (V, Cr, Mn, Fe, Co and Ni) have been analyzed by ab initio band calculations based on the density functional theory with the full-potential linearized-augmented-plane-wave method. When TiO2 is doped with V, Cr, Mn, Fe, or Co, an electron occupied level occurs and the electrons are localized around each dopant. As the atomic number of the dopant increases the localized level shifts to lower energy. The energy of the localized level due to Co is sufficiently low to lie at the top of the valence band while the other metals produce midgap states. In contrast, the electrons from the Ni dopant are somewhat delocalized, thus significantly contributing to the formation of the valence band with the O p and Ti 3d electrons. Based on a comparison with the absorption and photoconductivity data previously reported, we show that the t2g state of the dopant plays a significant role in the photoresponse of TiO2 under visible light irradiation. 相似文献