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1.
Wood samples treated with ammonium copper quat (ACQ 1900 and ACQ 2200), chromated copper arsenate (CCA), Tanalith E 3491 and Wolmanit CX-8 have been studied in accelerated weathering experiments. The weathering experiment was performed by cycles of 2 h UV-light irradiation followed by water spray for 18 min. The changes on the surface of the weathered samples were characterized by roughness and color measurements on the samples with 0, 200, 400 and 600 h of total weathering.

The objective of this study was to investigate the changes created by weathering on impregnated wood with several different wood preservatives. This study was performed on the accelerated weathering test cycle, using UV irradiation and water spray in order to simulate natural weathering.

Surface roughness and color measurement was used to investigate the changes after several intervals (0–200–400–600 h) in artificial weathering of treated and untreated wood.  相似文献

2.
Effect of accelerated weathering on surface chemistry of modified wood   总被引:1,自引:0,他引:1  
In this study, the effects of UV-light irradiation and water spray on colour and surface chemistry of scots pine sapwood samples were investigated. The specimens were treated with chromated copper arsenate (CCA), a metal-free propiconazol-based formulation, chitosan, furfuryl alcohol and linseed and tall oils. The weathering experiment was performed by cycles of 2 h UV-light irradiation followed by water spray for 18 min. The changes at the surface of the weathered samples were characterised by Fourier transform infrared spectroscopy (FT-IR); colour characterizations were performed by measuring CIELab parameters.The results show that all treatment methods except chitosan treatment provided lower colour changes than the control groups after 800 h exposure in weathering test cycle, but differences between chitosan and control were also small. The lowest colour changes were found on linseed oil (full cell process) and CCA treated wood. FT-IR results show that oil treatment (linseed and tall oil) decreased the intensities of a lignin specific peak (1500-1515 cm−1). Absorption band changes at 1630-1660 cm−1 were reduced by all treatments.  相似文献
3.
Strength and ultrasonic properties of cemented paste backfill   总被引:1,自引:0,他引:1  
This paper presents the strength (UCS) and ultrasonic pulse velocity (UPV) properties of cemented paste backfill (CPB) produced from two different mill tailings (Tailings T1 and T2). A total of 240 CPB samples with diameter × height of 5 × 10 cm and 10 × 20 cm prepared at different binder dosages (5–7 wt.%) and water-to-cement ratios (3.97–5.10) were subjected to the UPV and UCS tests at 7, 14, 28 and 56-days of curing periods. UCS and UPV of CPB samples increased with increasing the binder dosage and reducing the w/c ratio irrespective of the sample size and tailings type. CPB samples with a diameter × height of 5 × 10 cm were observed to produce consistently higher (up to 1.69-fold) UCSs than those of 10 × 20 cm CPB samples at all binder dosages and w/c ratios. However, at the corresponding binder dosages and w/c ratios, the maximum variation of UPV between the CPB samples of 5 × 10 cm and 10 × 20 cm was only 7.45%. Using the method of least squares regression, the UCS values were correlated with the UPV values for CPB samples of 10 × 20 cm in size. A linear relation with a high correlation coefficient appeared to exist between the UCS and UPV for CPB samples. These findings suggest that the UPV is essentially independent of the sample size. In this regard, the UPV test can be suitably exploited for the rapid estimation of the strength and quality of CPB samples even using small samples with concomitant benefits of reducing sample size.  相似文献
4.
The magnetic flux density in the cavity of a sintered tube of Yttrium Barium Copper Oxide (YBCO) is measured as a function of H, the axial magnetic field impressed and removed after zero field cooling (ZFC). We note that, in a short thick-walled hollow cylinder of a weak-linked polycrystalline high-Tc superconductor, the magnetic field in the cavity of the tube, Hz hole, rises above the applied field H when it is initially increasing. Consequently the standard approach to determine the critical current density from an ascending sweep of H alone, or a descending sweep alone cannot be exploited. However the field dependence of the intergranular critical current density Jcm can be reliably obtained from the horizontal traversals of Hz hole vs H. Comparison of the experimental data with model calculations for the horizontal traversals of the hysteresis curves show that the intergranular critical current density in the YBCO tube has a Kim-like field dependence. The magnetization of the grains has a significant influence on the flux density in the cavity of the tube.  相似文献
5.
Six Cu1−xCox alloy films were prepared by an electrodeposition technique. The compositions of the films were determined to be , 0.13, 0.17, 0.19, 0.21, 0.26 by an atomic absorption spectrophotometer. The crystal structure is FCC-Cu for all films but a shift in the diffraction lines is observed with increasing Co content. The giant magnetoresistance effect was determined in some of the films below 200 K. Magnetisation curves showed no saturation at 10 kOe and the curves of the samples which have a large magnetoresistance value are inclined more than the curves of the other low magnetoresistance samples. This may be due to the degree of magnetic moment distribution in these samples.  相似文献
6.
7.
The interacting boson model of Arima, Iachello, and co-workers is applied to the even ruthenium isotopes, ^96 Ru -116Ru. Excitation energies, electromagnetic transition strengths, quadrupole and magnetic dipole moments, and △(E2/M1) mixing ratios have been described systematically. Mixed symmetry states are investigated. It is seen that the properties of low-lying levels in these isotopes, for which the comparison between experiment and theory is possible, can be satisfactorily characterized by the Interacting Boson Model-2.  相似文献
8.
The interacting boson model of Arima, Iachello, and co-workers is applied to the even ruthenium isotopes,96 Ru ~ 116Ru. Excitation energies, electromagnetic transition strengths, quadrupole and magnetic dipole moments, and △(E2/M1) mixing ratios have been described systematically. Mixed symmetry states are investigated. It is seen that the properties of low-lying levels in these isotopes, for which the comparison between experiment and theory is possible,can be satisfactorily characterized by the Interacting Boson Model-2.  相似文献
9.
Chemical effects on the Kβ/Kα X-ray intensity ratios for some Mn, Ni, and Cu complexes of a new schiff-base with salen N2H2 type were investigated. The samples were excited by 59.543 keV γ-rays from a 241Am annular radioactive source. K X-rays emitted by samples were counted by a Si(Li) detector with resolution 157 eV at 5.9 keV. We observed the chemical effect on the Kβ/Kα X-ray intensity ratios for Mn, Ni and Cu complexes. The experimental results showed that the Kβ/Kα X-ray intensity ratios for compounds with complexes are generally larger than those with salt form. The experimental values have been compared with the other experimental and the theoretically calculated values of pure elements. The results are in very good agreement with the others.  相似文献
10.
The cross-section for Ca and K compounds were determined by measuring the KX-ray yields from targets excited 5.96 keV photons and using theoretical K shell photoionization cross-section. By comparing the experimental results with relativistic Hartree-Fock calculation, a good agreement has been obtained considering the experimental errors.  相似文献
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