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71.
72.
An analysis is presented for the problem of propagating acceleration waves in a binary, immiscible fluid mixture with compressible constituents. A purely mechanical theory is used to describe the behavior of the mixture, and the local volume fractions (concentrations) of the constituents appear among the independent variables in constitutive equations. These volume fractions are constrained by the condition that they sum to unity. The theory of singular surfaces is used to analyse the propagation of waves. A quartic equation is obtained whose solutions are the permissible wave speeds. Conditions for the growth or decay of the amplitude of the wave are also given. 相似文献
73.
We use Noether's theorem to derive energy-momentum tensors for a simple elastic material, a nonsimple elastic material of grade two, a simple elastic dielectric and a nonsimple elastic dielectric of grade two. The technique is easily extendable to a nonsimple elastic dielectric of any grade. 相似文献
74.
It has recently been established that physical realism of the results can be improved within the framework of the self-consistent statistical exchange multiple scattering wave method if the atomic spheres are allowed to overlap. Here we report that by semi-empirically adjusting the overlap of the atomic spheres, the ionization potentials and total energy are in better agreement with experiment, and the order of levels A1 and B2 in formaldehyde is reversed with respect to some other calculations. The electronic energy level structure calculated here is in agreement with the experimental results. A systematic study of the overlapping scheme for formaldehyde is presented and the results are compared with experiments and other theoretical calculations. 相似文献
75.
Studies toward the construction of functionalized piperidone derivatives from derivatives of Baylis-Hillman adducts are described. Interestingly the 6-oxo-4-aryl-piperidine-3-carboxylates generated during the study serve as precursor for the facile synthesis of 4-oxo-6-aryl-3-aza-bicyclo[3.1.0]hexane-1-carboxylates. 相似文献
76.
[reaction: see text] Herein, we describe the synthesis of fluorescent 2-(arylsulfonyl)methacrylates and its polymers. These novel trifunctional monomers, possessing a fluorescent arylsulfonyl (ArSO(2)) group, an alkyl group (R), and a polymerizable olefin, serve as useful building blocks for functionalized fluorescent polymers. 相似文献
77.
Summary Manganese(II) complexes of bis(2-benzimidazolylmethyl) ether (DGB), bis(2-benzimidazolylmethyl) sulphide (TGB) and the n-butyl derivative of DGB (BDGB) were prepared and characterised. The solution e.p.r. spectrum of [Mn(TGB)Cl2] in DMF at 143 K is commensurate with an axially distorted monomeric manganese(II) complex, room temperature magnetic moment
(6.04 B.M.) per manganese(II) atom being in the range found for other d5 monomeric manganese(II) complexes. The solution e.p.r. spectrum of [Mn(BDGB)Cl2]-2H2O in DMF at 143 K indicates the presence of two equivalent manganese(II) ions coupled by an exchange interaction, fostered
by bridging chlorides. Evidence for this is provided by a nearly isotropic 11 line hyperfine structure of 55Mn, with a coupling constant 45 ± 5G. Contact-shifted 1H n.m.r. data also supports an exchange coupled dimeric manganese complex. The room temperature magnetic moment, 5.64 B.M.,
per manganese(II) indicates quenching of the magnetic moment below that of monomeric manganese(II) ion. The [Mn(DGB)Cl2]·H2O complex exhibits a magnetic moment of 6.02 B.M. per manganese, indicating a monomeric manganese complex. E.p.r. data of
the complex diluted in an analogous Zn-DGB complex (1∶20) correlates well for D = 0.22cm−1 and λ ∼- 0.267. The [Mn(DGB)-(C1O4)2] and [Mn(BDGB)(ClO4)2] complexes, diluted in analogous Zn-DGB and Zn-BDGB complexes (1∶20), show a strong single e.p.r. line at g
eff ∼- 2. The complexes have low magnetic moments; 4.44 B.M./Mn and 4.39 B.M./Mn, at room temperature. 相似文献
78.
F. A. L. Dullien M. S. El-Sayed V. K. Batra 《Journal of colloid and interface science》1977,60(3):497-506
An equation for the rate of capillary rise in porous media with nonuniform pores has been derived on the basis of a three-dimensional network model of pore structure, consisting of a repeating capillary element with step changes in its diameter. The measured rates of capillary rise of water in a number of sandstone samples have been accurately predicted by the model. The apparent capillary diameter for the rate of the capillary rise has been found to be several orders of magnitude smaller than the pore diameter corresponding to the peak of the mercury intrusion porosimetry curve. The permeability of the sandstone samples has been found to be approximately directly proportional to the apparent diameter of the rate of capillary rise. This approximate proportionality has been shown to follow from the capillary network model of the pore structure used in this work. 相似文献
79.
Cluster model calculations suggest that the molecular orbitals of CO are significantly perturbed upon chemisorption on Ni. The CO-Ni interaction is found to involve the Ni-d electrons in addition to the s-and p-derived states, contrary to some earlier suggestions. Based on our results, a new interpretation is proposed for the observed photoemission spectra of CO on Ni, which is consistent with the large bonding and relaxation shifts in other systems. 相似文献
80.
We describe a method for determining the interaction potential between a helium atom and a metal surface from diffraction data. Results are presented for He/Ni(110) and He/Cu(110). For He/Cu(110) the potential 3s in good agreement with a first principles calculation but this is not true for He/Ni(110). We also show that a surface relaxation of 10% produces measurable changes in intensities. 相似文献