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31.
Sulfur capacity of SiO2, TiO2 and γ-Al2O3 structures was investigated. Thermal treatment of TiO2 and γ-Al2O3 in air increased their respective sulfur capacity by 67 and 43%. Sulfur capacity was associated with surface acidity and
the improvement attributed to the formation of bronsted acid sites. Addition of 4wt% transition metals further enhanced the
sulfur capacity of TiO2 with Ag indicating the highest increase. Comparison of sulfur capacity of Ag/TiO2 with other adsorbents was made using JP5 fuel with sulfur concentration of 1172 ppmw. Ag/TiO2 adsorbent demonstrated a saturation sulfur capacity of 8.20 mg/g. A significant loss in sulfur capacity was observed between
real and model fuel compositions. Various factors resulting in this loss was investigated such as the effect of additives,
competitive adsorption and the structure of sulfur heterocycles. 相似文献
32.
REMEDIOS GONZÁLEZ-LUQUE MANUELA MERCHÁN MERCEDES RUBIO LUIS SERRANO-ANDRÉS BJÖRN O. ROOS MIGUEL-ÁNGEL MIRANDA 《Molecular physics》2013,111(13):1977-1982
The lower excited states of 2-benzoylthiophene have been studied using ab initio quantum chemical methods based on multiconfigurational wave functions. Six singlet and six triplet excited states have been characterized. The geometry has been optimized for the two lowest triplet states, which are responsible for the photoreactivity of the chromophore in the photosensitizing drug tiaprofenic acid. The T1(π → π?) and T2(n → π?) states have been found to be close in energy with the π → π? state slightly lower. The excited states have been characterized using density difference and spin density plots. The different photochemical behaviour of the two triplet states can be rationalized from the theoretical data. 相似文献
33.
Vladimir V. Tatarchuk Anastasiya P. Sergievskaya Irina A. Druzhinina Vladimir I. Zaikovsky 《Journal of nanoparticle research》2011,13(10):4997-5007
The kinetics of the growth of gold nanoparticles during the reduction of tetrachloroauric acid by hydrazine in dispersed aqueous
solution encapsulated by reverse micelles of Triton N-42 surfactant (with decane as dispersion medium) was studied by means
of spectrophotometry. According to DLS data, at a set value of solubilization capacity V
s/V
o = 0.005 initial micelles have an aqueous core hydrodynamic diameter d
c = 3.6±0.2 nm. The final particles obtained after full reduction of AuIII have a metallic core of defect-free single-crystalline gold with a narrow size distribution and average core diameter d
Au = 7.7 ± 1.4 nm as shown by TEM. The rate of the particle growth is limited by the rate of gold reduction. The process kinetics
corresponds to the model consisting of two stages of reduction AuIII → AuI → Au0. The stages involve the formation and redox decay of the intermediate complexes Au(N2H4)Cl3 and Au(N2H4)Cl, and each stage proceeds via two routes: (1) homogeneous in the dispersed aqueous phase, and (2) heterogeneous on the
particle surfaces. Reactions taking route (2) are autocatalytic because they proceed with participation of the surface atoms
of particles as the final products of AuIII reduction. The dependencies of observed rate constants on reagent concentrations, temperature, and solubilization capacity
of the micellar solution are studied. 相似文献
34.
BJÖRN O. ROOS 《Molecular physics》2013,111(1-2):87-91
Results are presented from a theoretical study of the × 6Σ+, A 6Σ+ and 6Δ electronic states of CrH using multiconfiguration second-order perturbation theory in the multi-state formalism (MS-CASPT2). It is shown that the results for the spectroscopic constants and radiative lifetimes for the A state are in agreement with experiment and an earlier multireference configuration interaction study only if the two close lying × and A states are allowed to interact at a level of approximation that includes dynamic correlation. 相似文献
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V. V. Tatarchuk A. I. Bulavchenko I. A. Druzhinina 《Russian Journal of Inorganic Chemistry》2007,52(8):1284-1288
The dissolution of silver nanoparticles in their reaction with aqueous HNO3 solubilized to an reverse micelle solution of sodium bis(2-ethylhexyl)sulfosuccinate in decane is studied spectrophotometrically. A physicochemical model is advanced for quantifying the process kinetics on th basis of the following autocatalytic scheme: Ag0 + H+ + NO 3 ? → Ag+ + products (k 1), and Ag0 + Ag+ + NO 3 ? → 2Ag+ + products (k 2). The effective rate constant k 2 decreases with decreasing solubilization capacity V S/V O (where V S is the volume of the solubilized dispersed aqueous phase and V O is the volume of the micelle solution); the solubilization capacity determines the size of the micelle cavities in which the reaction between Ag0 and HNO3 occurs: k 2 = 74 (V S/V O) · 100% ≈ 3.8%), 41 (2.9), and 35 (2.0) L/(mol s). The effective constant k 1 is determined with a high uncertainty; the effect of V S/V O on k 1 has the opposite tendency. 相似文献
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