We propose a variant of thermodynamic perturbation theory based on the Mayer f-function which is applicable to strongly repulsive, and even singular interactions. The expansion of the free energy is successfully tested against known ‘exact results’ for hard-sphere fluids, and then applied to binary mixtures of particles with non-additive hard cores or shouldered potentials. The resulting phase diagrams agree well with existing simulation data and theoretical predictions. 相似文献
The preparation of microfibrillar cellulose (MFC) films by filtration on a polyamide filter cloth, in a dynamic sheet former
and as a surface layer on base paper is described. Experimental evidence of the high tensile strength, density and elongation
of films formed by MFC is given. Typically, a MFC film with basis weight 35 g/m2 had tensile index 146 ± 18 Nm/g and elongation 8.6 ± 1.6%. The E modulus (17.5 ± 1.0 GPa) of a film composed of randomly oriented fibrils was comparable to values for cellulose fibres with
a fibril angle of 50°. The strength of the films formed in the dynamic sheet former was comparable to the strength of the
MFC films prepared by filtration. The use of MFC as surface layer (0–8% of total basis weight) on base paper increased the
strength of the paper sheets significantly and reduced their air permeability dramatically. FEG-SEM images indicated that
the MFC layer reduced sheet porosity, i.e. the dense structure formed by the fibrils resulted in superior barrier properties.
Oxygen transmission rates (OTR) as low as 17 ml m−2 day−1 were obtained for films prepared from pure MFC. This result fulfils the requirements for oxygen transmission rate in modified
atmosphere packaging. 相似文献
One Heck of a reaction : Treatment of arylboronic acids or aryltrifluoroborates with vinyl acetate by using a palladium(II) catalyst gives the corresponding styrenes (see scheme). No palladium reoxidant is needed and the vinylation is performed under non‐inert conditions
The first PdII‐catalyzed P arylation has been performed by using palladium acetate, the rigid bidentate ligand dmphen (dmphen=2,9‐dimethyl‐1,10‐phenanthroline), and without the addition of base or acid. Couplings of arylboronic acids or aryl trifluoroborates with H‐phosphonate dialkyl esters were conducted in 30 min with controlled microwave (MW) heating under non‐inert conditions. Aryl phosphites were also synthesized at room temperature with atmospheric air as the sole reoxidant. The arylated phosphonates were isolated in 44–90 % yields. The excellent chemoselectivity of the method was illustrated in the synthesis of a Mycobacterium tuberculosis glutamine synthetase (MTB‐GS) inhibitor. Online ESIMS was used to detect cationic palladium species in ongoing reactions directly, and a catalytic cycle has been proposed based on these results. 相似文献
Summary Molecular electrostatic potentials have been used to model the calcium binding properties of some bisphosphonate drugs, which are used to treat various bone diseases. The mechanism of action involves the binding of bisphosphonates to the bone surface, where calcium plays an important role. Electrostatic potential maps derived from ab initio partial charges have been compared with both the crystal structure and the fully optimized ab initio structure of (dichloro)methylenebisphosphonate-calcium ion complex. Molecular electrostatic potentials can correctly predict the calcium binding geometry of bisphosphonate-type compounds and this type of information can be used in the practical drug design work. 相似文献
It is known that the spline system of orderm is an unconditional basis forHp[0,1] whenp>1/(m+2) and a Schauder basis whenp ≧1/(m+2). We show that these results are sharp. 相似文献
The infrared spectrum of fulminic acid, HCNO, was measured with high resolution in the region 500–657 cm?1. The spectrum was obtained with a Bomem interferometer, at a reslution of about 0.006 cm?1. Thirteen bands could be identified and assigned to rovibrational transitions of HCNO. These are the fundamental ν4 and some of its hot bands, and the overtone 2ν5 and some of its hot bands. Because ν5 is a quasilinear bending mode, the identification and measurement of the various hot bands is especially important for locating the combination states of ν4 with various quanta of ν5. 相似文献