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11.
Kazunori Matsumura Kikuko Hayamizu Osamu Yamamoto 《Journal of Polymer Science.Polymer Physics》1989,27(12):2407-2418
1H-NMR and 2H-NMR spectra of water (H2O and D2O) absorbed in Visking cellulose tubing have been observed as a function of the angle Θ between the film surface and the magnetic field. 1H-NMR spectra show broad lines, and the chemical shift and the linewidth depend on Θ. From the angular dependence of the chemical shift, the anisotropic volume diamagnetic susceptibilities of the film are determined, i.e., χ∥ in the direction longitudinal to the tubing (stretched direction) is 0.43 ppm, and χ⊥ in the transverse direction is 0.57 ppm. The different values of χ∥ and χ⊥ afford an evidence of the anisotropy of the film. 2H-NMR spectra of D2O absorbed in the film show quadrupole splitting which also depends on Θ. The angular dependences of the linewidth (1H-NMR) and the quadrupole splitting (2H-NMR) indicate that the H? H axes of the water molecules have a tendency to orient in the direction longitudinal to the film surface. 相似文献
12.
13.
The reaction of singlet oxygen with N-1-(2-alkenylidene)-t- butylamines (
and
) gives the unsaturated hemiperacetal derivatives (
and 4) of the hydroperoxy aldimines (
and
). Several α, β-unsaturated aldimines which are held in the s-trans conformation failed to react with singlet oxygen. 相似文献
14.
Irradiation of an acetonitrile solution containing cyclohexylidenepropanedinitrile (1) and allyltrimethylsilane (2) in the presence of phenanthrene afforded two kinds of allylated products (3, 4) and a reduction product (5). The product ratio of 3, 4, and 5 dramatically changed depending on the pK(a) values of additives. 相似文献
15.
S. Sugai Y. Takayanagi N. Hayamizu T. Muroi J. Nohara R. Shiozaki K. Okazaki K. Takenaka 《Physica C: Superconductivity and its Applications》2010
Electronic Raman scattering has no sum rule in no and weak correlation, but the existence of sum rule has been proposed in strong correlation. The present Raman scattering disclosed that the first moment of the Raman susceptibility is proportional to the generalized moment of the optical conductivity in the metallic phase. The present experiment disclosed that a large amount of electronic states are incoherent states. The incoherent states are the relevant states for the superconductivity, because the gap opens in the incoherent states as well as the coherent states. 相似文献
16.
Maeda Y Kanda M Hashimoto M Hasegawa T Kimura S Lian Y Wakahara T Akasaka T Kazaoui S Minami N Okazaki T Hayamizu Y Hata K Lu J Nagase S 《Journal of the American Chemical Society》2006,128(37):12239-12242
The dispersion of small-diameter single-walled carbon nanotubes (SWNTs) produced by the CoMoCAT method in tetrahydrofuran (THF) with the use of amine was studied. The absorption, photoluminescence, and Raman spectroscopies showed that the dispersion and centrifugation process leads to an effective separation of metallic SWNTs from semiconducting SWNTs. Since this method is simple and convenient, it is highly applicable to an industrial utilization for widespread applications of SWNTs. 相似文献
17.
Futaba DN Hata K Namai T Yamada T Mizuno K Hayamizu Y Yumura M Iijima S 《The journal of physical chemistry. B》2006,110(15):8035-8038
We propose a statistical and macroscopic analysis to estimate the catalyst activity of water-assisted growth (super-growth) of single-walled nanotubes (SWNT) and to characterize SWNT forests. The catalyst activity was estimated to be 84% (+/-6%), the highest ever reported. The SWNT forest was found to be a very sparse material where SWNTs represent only 3.6% of the total volume. This structural sparseness is believed to play a critical role in achieving highly efficient growth. 相似文献
18.
Tokuda H Hayamizu K Ishii K Susan MA Watanabe M 《The journal of physical chemistry. B》2005,109(13):6103-6110
The alkyl chain length of 1-alkyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide ([Rmim][(CF(3)SO(2))(2)N], R = methyl (m), ethyl (e), butyl (b), hexyl (C(6)), and octyl (C(8))) was varied to prepare a series of room-temperature ionic liquids (RTILs), and the thermal behavior, density, viscosity, self-diffusion coefficients of the cation and anion, and ionic conductivity were measured over a wide temperature range. The self-diffusion coefficient, viscosity, ionic conductivity, and molar conductivity change with temperature following the Vogel-Fulcher-Tamman equation, and the density shows a linear decrease. The pulsed-field-gradient spin-echo NMR method reveals a higher self-diffusion coefficient for the cation compared to that for the anion over a wide temperature range, even if the cationic radius is larger than that of the anion. The summation of the cationic and anionic diffusion coefficients for the RTILs follows the order [emim][(CF(3)SO(2))(2)N] > [mmim][(CF(3)SO(2))(2)N] > [bmim][(CF(3)SO(2))(2)N] > [C(6)mim][(CF(3)SO(2))(2)N] > [C(8)mim][(CF(3)SO(2))(2)N], which greatly contrasts to the viscosity data. The ratio of molar conductivity obtained from impedance measurements to that calculated by the ionic diffusivity using the Nernst-Einstein equation quantifies the active ions contributing to ionic conduction in the diffusion components, in other words, ionicity of the ionic liquids. The ratio decreases with increasing number of carbon atoms in the alkyl chain. Finally, a balance between the electrostatic and induction forces has been discussed in terms of the main contribution factor in determining the physicochemical properties. 相似文献
19.
Pulsed gradient spin-echo (PGSE) NMR measurements of the self-diffusion coefficients of low viscosity liquids are greatly hampered by the effects of convection especially away from ambient temperature. Here we report on a new NMR tube designed to minimize the deleterious effects of convection. In this tube, which derives from a Shigemi symmetrical NMR tube, the sample is contained in an annulus formed from a concentric cylinder of susceptibility matched glass. The performance of this tube was demonstrated by conducting measurements on the electrochemically important LiN(SO3CF3)2 (LiTFSI)-diglyme (DG) system. Calibrations were first made using DG at column heights of 2, 3, and 4-mm in the temperature range between -40 and 100 degrees C. Measurements of the diffusion coefficients of the lithium, anion, and DG were then performed to probe the solvent-ion and ion-ion interactions in the DG doped with LiTFSI. Changes in the 1H, 7Li, and 19F PGSE-NMR attenuation curves at -40 degrees C provided clear evidence of interactions between the DG and lithium ion. 相似文献
20.
Osamu Yamamoto Kikuko Hayamizu Masaru Yanagisawa 《Journal of organometallic chemistry》1974,73(1):17-25
The kinetic parameters of the bridge-terminal interconversion of triethylaluminum (TEA) in cyclopentane and in toluene as well as of tri-n-propylaluminum (TPA) in cyclopentane are obtained from the total line shape analysis of 13C NMR spectra with proton-decoupling. The enthalpies and entropies of activation of these aluminum alkyls and of trimethylaluminum (TMA) in both solvents are nearly the same, but the interconversion is faster in toluene than in cyclopentane, and also becomes faster as the alkyl chain of the aluminum compounds becomes longer. From these data and the heats of dissociation obtained thermochemically by M.B. Smith [J. Phys. Chem., 71 (1967) 365; J. Organometal. Chem., 21 (1970) 273, 46 (1972) 31 and 211], a possible mechanism of the bridge-terminal exchange is elucidated, in which the exchange proceeds “intramolecularly” for TMA and presumably TEA in cyclopentane. For the aluminum alkyls in toluene and for TPA in cyclopentane, on the other hand, the exchange may proceed “intermolecularly” with only a little contribution from an “intramolecular process”. 相似文献