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421.
Examples of isotropic Kähler manifolds (i.e., J2=0) which are neither complex nor symplectic, and therefore not indefinite Kähler, are constructed. 相似文献
422.
Ono M Takara Y Egami M Uranaka K Yoshimitsu H Matsushita S Fujiwara Y Ikeda T Nohara T 《Chemical & pharmaceutical bulletin》2006,54(2):237-239
Two new steroidal alkaloid glycosides, esculeosides C and D, have been isolated from the ripe fruit of Cherry tomato [Lycopersicon esculentum var. cerasiforme (DUNAL) ALEF.], along with three known steroidal alkaloid glycosides, esculeoside A, esculeoiside B, and lycoperoside G. Their chemical structures were determined on the basis of spectroscopic data. 相似文献
423.
A new compound, Fe2+(1.5)Pb2+(5.5)In3+(10)S2-(22), was found in the Fe-Pb-In-S system. The crystals had a shiny metallic gray luster and were obtained in a barlike shape. The melting and recrystallizing points are 1098 and 1090 K, respectively. The crystal structure determined by X-ray diffraction is P2/m, a = 14.558(1) A, b = 3.8556(3) A, c = 15.558(1) A, beta = 96.876(1) degrees , V = 867.0(1) A(3), Z = 1, Dc = 5.893 g/cm(3), and R1 = 3.78%, which is an isostructure with Sn(5.5)In(11)S(22). In the structure, lead atoms exist at three crystallographically independent sites, and one of them, Pb1, is occupied by a quarter of indium atoms. All of the Fe ions are randomly distributed at six indium sites. This compound is a semiconductor with a band gap, E(a) = 0.95 eV. The dominant magnetic interaction is antiferromagnetic, but magnetic orderings are not observed down to 2 K. 相似文献
424.
Iwai Y Kita K Matsushita Y Yamauchi A Kihara M 《Chemical & pharmaceutical bulletin》2002,50(3):441-443
The new coupling reaction of phenacylamines with silylstannane and lithium diisopropylamide (LDA) is reported. The treatment of a phenacylamine iodide 1 with (trimethylsilyl)tributylstannane (Me3SiSnBu3) and cesium fluoride (CsF) gave a dimerization product 2 having no iodine atom. Reaction of 1 with LDA afforded a dimerization product 3 with an iodine atom. The products 2 and 3 were separated to the meso and racemic isomers, respectively. 相似文献
425.
The effects of misfit dislocations in epitaxial PbS/PbSe bi-crystals on the channeling of energetic He ions were studied. The direct scattering of channelling ions at dislocations was detected and its dependence on the energy of the incident ions was measured. 相似文献
426.
427.
A. Matsushita Y. Miyake Y. Murata K. Nishiyama K. Nagamine D. G. Fleming M. Morita T. Ohmi 《Hyperfine Interactions》1991,65(1-4):1071-1080
Evidence for the emission of slow muonium atoms from a 3.0-nm-thick SiO2 layer covered on an n-type Si is reported. Also, upon applying an rf-resonance technique at the muon frequency, a time-differential
observation of a delayed state-change from muonium to diamagnetic muon at room temperature was observed. Combining results
obtained by use of longitudinal field decoupling and transverse spin rotation methods, the conversion rate was estimated to
be 5 to 10 μs−1. Both of the above results, namely the observation of the emission and state-change of muonium, suggest a process in which
μ+ initially captures an electron from Si, then quickly converts to μ+ again during thermal diffusion in the Si towards the SiO2 layer. Within the oxide layer, muonium is again formed and subsequently is emitted from the SiO2 surface. 相似文献
428.
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