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81.
I. Kaneko T. Sekine K. Yoshihara 《Journal of Radioanalytical and Nuclear Chemistry》1990,144(2):89-96
Appearance energy is originally the threshold energy at which récoil products begin to be observed. This was determined by /, '/ reactions. Afterwards, an alternative technique has been developed to determine it by summing up recoil energy spectrum. The latter technique assumed a step function rising at energy EO in the yield-energy relation. EO should be defined as normalized appearance energy /NAE/, because it is not threshold energy in its original sense. The NAE for isomerization from to /or reverse/ in Ru/acac/3 was estimated to be 29 eV, and that for free atom /or ion/ formation was calculated to be 34 eV. The 5 eV difference seems to indicate an energy interval in which isomerization effectively occurs in the recoil reaction. 相似文献
82.
Kazuya Ogawa Tieqiao Zhang Keitaro Yoshihara Yoshiaki Kobuke 《Journal of the American Chemical Society》2002,124(1):22-23
Third-order nonlinear optical properties of two series of self-assembled porphyrin wires, one being terminated by zinc porphyrin and the other by free base porphyrin, were measured by femtosecond time-resolved optical Kerr effect. The hyperpolarizability values of the latter series were extremely large ranging from 10-30 to 10-29 esu, 10 times larger than the former. The behavior is accounted for by the contribution of terminal free base porphyrin to enhance the molecular polarization by acceptor nature toward central metalloporphyrin array. 相似文献
83.
Sekine T. Yoshihara K. Németh Zs. Lakosi L. Veres Á. 《Journal of Radioanalytical and Nuclear Chemistry》1989,130(2):269-278
A new nuclear excitation process,99Tc (, )99mTc reaction, was applied for the first time to radioactivation analysis of technetium. Bremsstrahlung irradiation of99Tc samples gave the reaction product99mTc which emits -ray measurable with ease by a semiconductor detector. The production rate of99mTc per g99Tc was linearly correlated with the flux of bremsstrahlung. The detection limit of99Tc was estimated to be nanogram order (0.63 Bq99Tc) under the optimum irradiation condition. Possible interference by100Ru(, p)99mTc reaction was also studied, which could be discriminated from the (, ) reaction by simultaneously occurring98Ru (, p)97Ru reaction. 相似文献
84.
Yasushi Joh Yahide Kotake Toshio Yoshihara Fumio Ide Kazuo Nakatsuka 《Journal of polymer science. Part A, Polymer chemistry》1967,5(3):605-617
Stereospecific polymerization of methacrylonitrile with diethylmagnesium has been studied. Polymerization temperature has an important effect on polymerization. The conversion, stereoregularity, and intrinsic viscosity of the polymer increased significantly with increasing polymerization temperature. Stereoregularity of the polymer improved with increasing the polymerization time and the monomer concentration, but it is independent of the catalyst concentration. Intrinsic viscosity of the crystalline polymer increased with increasing monomer concentration but is independent of the polymerization time and the catalyst concentration. It is suggested that two mechanisms are involved in this polymerization: coordinated anionic polymerization to from the crystalline polymer, and probably conventional anionic polymerization to form the amorphous polymer. It is found that crystalline polymer can also be obtained in homogeneous phase such as in tetrahydrofuran solvent. 相似文献
85.
Recoil implantation of Tc and Ru in metal acetylacetonates were performed using ruthenium metal as a source and MIII/acac/3 and MII/acac/2 complexes as catchers. The recoil atoms were obtained by100Ru/, p/99mTc and98Ru/, n/97Ru reactions. The yields of Tc/acac/3 and Ru/acac/3 were clearly dependent on the force constant of the bond between the central metal atom and oxygen in acetylacetone K/M–O/. A plot of the yield vs. 1/K(M–O) showed a linear relationship. However, the yield of Tc/acac/2 implanted in M/acac/2 did not show such a dependence on the force constant. The difference of the mechanism of complex formation between Tc/acac/3 and Tc/acac/2 was discussed on the basis of a reaction cage surrounding the recoil atom and of reaction time necessary for competition between the recoil atom and the central metal of the catcher complex. 相似文献
86.
G. Izawa H. Fujiwara T. Omori K. Yoshihara H. Arai K. Sera K. Ishii 《Journal of Radioanalytical and Nuclear Chemistry》1987,118(1):59-67
Chemical effects on the intensity ratio of LX-ray of molybdenum compounds irradiated by 11-keV electrons and by 3-MeV protons were studied using an X-ray crystal spectrometer. It was found that the intensity ratios of L1/L1 markedly decrease with increase of ionicity of molybdenum compounds. An exception was for the case of metallic molybdenum. 相似文献
87.
88.
89.
为了人类持久的能源供应及日益严重的环境问题,由石化能源逐步过渡到以再生能源为主的时代终将来临。本文简单介绍了新能源在我国发展的优势、条件及目前的发展状况。 相似文献
90.