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1.
Heavy ion irradiation in the electronic stopping power region induces macroscopic dimensional change in metallic glasses and introduces magnetic anisotropy in some magnetic materials. The present work is on the irradiation study of ferromagnetic metallic glasses, where both dimensional change and modification of magnetic anisotropy are expected. Magnetic anisotropy was measured using Mössbauer spectroscopy of virgin and irradiated Fe40Ni40B20 and Fe40Ni38Mo4B18 metallic glass ribbons. 90 MeV 127I beam was used for the irradiations. Irradiation doses were 5×1013 and 7.5×1013 ions/cm2. The relative intensity ratios D 23 of the second and third lines of the Mössbauer spectra were measured to determine the magnetic anisotropy. The virgin samples of both the materials display in-plane magnetic anisotropy, i.e., the spins are oriented parallel to the ribbon plane. Irradiation is found to cause reduction in magnetic anisotropy. Near-complete randomization of magnetic moments is observed at high irradiation doses. Correlation is found between the residual stresses introduced by ion irradiation and the change in magnetic anisotropy. 相似文献
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In subnormal glow discharge under d.c. excitation at different pressure in a varying transverse magnetic field (0 to 30 G)
some measurements have been carried out for various initial average tube currents. The voltage across the discharge increases
and average tube current and residual current decreases in the magnetic field. With the help of Beckman’s expression [4] for
the axial field and the electron density distribution in a transverse magnetic field the observed variation of current and
voltage can be satisfactorily explained. The variation of axial electric field with transverse magnetic field can be represented
to a fair degree of accuracy by the derived equation. The behaviour of residual current with magnetic field has been observed
in these oscillations. 相似文献
4.
A new method for the synthesis of aristolochic acids and their homologues was presented. According to the above procedure 3,4,6,7-tetramethoxy-10-nitrophenantrenecarboxylic acid was obtained from a product of glaucine degradation and its chemical structure was proved. 相似文献
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Assuming that a pulse of excitation corresponds to the logical "true" state one can use a chemical medium for information processing and construct devices that execute the basic binary logical operations. Here we discuss direct chemical realizations of four argument logical functions equivalent to special types of McCulloch-Pitts neuron. We demonstrate that if a proper geometrical arrangement of excitable and nonexcitable areas is used then the construction of the considered devices can be much simpler than in the case where they are composed of chemical binary logical gates. 相似文献
8.
In view of applications of SiOxNy thin films in MOEMS technology, a study of the optomechanical characteristics of the PECVD deposited material are investigated. To optimize the quality of SiOxNy layers we establish the relationship between the chemical properties, optical performances, micromechanical stress, and growth parameters of deposited films. To use the SiOxNy thin film for the core layer of a strip-loaded waveguide, we propose preparation conditions of SiOxNy that offer a low-loss optical waveguide with well-controlled refractive index, based on a low-internal stress multilayer structure. 相似文献
9.
DC Muddiman AP Null JC Hannis 《Rapid communications in mass spectrometry : RCM》1999,13(12):1201-1204
Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS) has been used to determine the mass of a double-stranded 500 base-pair (bp) polymerase chain reaction (PCR) product with an average theoretical mass of the blunt-ended (i.e. unadenylated) species of 308 859.35 Da. The PCR product was generated from the linearized bacteriophage Lambda genome which is a double-stranded template. Utilization of ethanol precipitation in tandem with a rapid microdialysis step to purify and desalt the PCR product was crucial to obtain a precise mass measurement. The PCR product (0.8 pmol/μL) was electrosprayed from a solution containing 75% acetonitrile, 25 mM piperidine, and 25 mM imidazole and was infused at a rate of 200 nL/min. The average molecular mass and the corresponding precision were determined using the charge-states ranging from 172 to 235 net negative charges. The experimental mass and corresponding precision (reported as the 95% confidence interval of the mean) was 309 406 +/- 27 Da (87 ppm). The mass accuracy was compromised due to the fact that the PCR generates multiple products when using Taq polymerase due to the non-template directed 3'-adenylation. This results in a mixture of three PCR products with nearly identical mass (i.e. blunt-ended, mono-adenylated and di-adenylated) with unknown relative abundances that were not resolved in the spectrum. Thus, the experimental mass will be a weighted average of the three species which, under our experimental conditions, reflects a nearly equal concentration of the mono- and di-adenylated species. This report demonstrates that precise mass measurements of PCR products up to 309 kDa (500 bp) can be routinely obtained by ESI-FTICR requiring low femtomole amounts. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
10.
C. Gorecki 《Optics & Laser Technology》1989,21(2)
Two coherent optical approaches to the classification of rough surfaces using Fourier techniques are compared. Results for various machined metal samples show the potentials of these non-destructive techniques for roughnesses of Rt ranging from 0.1 to 10 μm. 相似文献