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81.
The charge-transfer (CT) transition of complexes involving alkylated aromatic electron donors shifts hypsochromically upon benzylic deuteration. This is attributed to hyperconjugative effects. 相似文献
82.
83.
G. J. De Jong U. A. Th. Brinkman W. Th. Kok 《Journal of Radioanalytical and Nuclear Chemistry》1977,35(2):245-252
An investigation has been made on the system liquid anion-exchanger-Cd(II)-NCS−. The influence of the acidity and thiocyanate concentration of the aqueous phase on the extraction has been studied. Using
various methods of analysis, it has been shown that the complex anion present in the organic extracts is Cd(NCS)
4
2−
. Details are given concerning the removal of traces of Zn(II) from Cd(II)-containing solutions, and the quantitative separation
of Cd(II) from Cr(III). 相似文献
84.
Stress fields between interacting small particles ( approximately 100 nm) have been investigated by transmission electron microscopy. The background for these TEM observations is discussed in terms of adhesion stress fields (due to surface forces), the action of an applied point force, possibly magnetic, and dislocations or misfit strains due to an unfavorable matching of crystal lattices at the grain boundary. A further explanation might be sought along the line "squeezed-in oxide" which can be visualized as a coherent particle or a dislocation loop. Accompanying theoretical calculations have been performed and compared with the experimental results. 相似文献
85.
Summary The pozzolanic reactivity of thermally treated zeolites was studied on the basis of the Chapelle test combined with X-ray
diffraction (XRD) and Fourier Transform (FTIR) spectroscopy, as well as thermogravimetric analysis (TG/DTG) and differential
thermal analysis (DTA). The raw zeolite samples are from the Pentalofos area, Thrace, NE Greece. Their main mineral constituent
is 'heulandite type-II', an intermediate type of the heulandite-clinoptilolite isomorphous series. Calcination of the samples
was carried out up to 400, 500, 600, 700 and 1000°C for 15 h. The changes were recorded using the above methods. The deformation
of the zeolite crystal lattice starts at about 400°C and proceeds as the temperature of thermal treatment rises. The thermal
treatment of zeolite at 400°C improves its pozzolanic reactivity and accelerates the reaction with Ca(OH)2. 相似文献
86.
Isotherms and differential enthalpies of adsorption are obtained for nitrogen at ambient temperature on monovalent (Li(+), Na(+), K(+)) and divalent (Ca(2+), Ba(2+), Sr(2+), Mn(2+)) substituted X-faujasite systems by microcalorimetry measurements. These experimental data are compared with those obtained by combining grand canonical Monte Carlo simulations and newly derived force fields for describing the interactions between the extra-framework cations and the adsorbates obtained from a simple model based only on the intrinsic properties of the cations. It is the first time that such good qualitative agreement is reported between experiment and simulation for a series of both monovalent and divalent cations. 相似文献
87.
With regard to the ideal network it is shown that the concept ofN non-interacting polymer chains can be transformed in a problem of non interacting excitations (called conformons) for rubber elasticity. Modelling the interaction on permanent crosslinks as a scattering problem and taking the finite chain length into account, an interpretation of the second Mooney coefficient can be given. There is some evidence that the junctions move by constrained self diffusion.Dedicated to Prof. Dr. W. Ruland on the occasion of his 60th birthday. 相似文献
88.
Fluorocarbons containing higher halogens have the potency of breaking certain hydrogen bonds in solutions. The relative strength of this potency varies in the series F < Cl < Br < I and the presence of hydrogen atoms in the fluorocarbon increases it. There is a striking parallelism between the hydrogen bond breaking and the anaesthetic potency of these molecules. It is suggested that the breaking of hydrogen bonds is an important step in the mechanism of anaesthesia. 相似文献
89.
E. Robens D. Möhlmann Th. Gast R. Staudt M. Eger 《Journal of Thermal Analysis and Calorimetry》2006,86(1):27-29
The balance is the most widely used complex measuring instrument in
science and techniques. To install a balance on Mars is a challenge for numerous
aspects of in situ measurements in the next decade. By means of a balance
useful parameters could be determined and a variety of investigations could
be carried out there. Possible applications of a balance on Mars are reviewed.
Choice of type and demands on the balance with regard to the conditions on
Mars are discussed. The first step is to test a load cell with strain gauge
deflection sensor. 相似文献
90.
Monitoring data from chemical analysis of rainwater and aerosol samples collected in an urban area have been interpreted by the use of environmetric approaches. An attempt was done to compare the data set structures of both type of precipitation and to estimate the contribution of different anthropogenic and naturally occurring emission sources to the total mass of the wet and dry precipitation. It was found that three latent factors explaining over 80% of the total variance of the set are responsible for the rainwater set structure-'sea spray', 'soil dust', and 'anthropogenic'. Only two were the latent factors explaining the dominant part of the variance in the case of aerosol samples-'anthropogenic' and 'natural'. It is shown that the anthropogenic influence for aerosol samples is more complex that that of rainwater samples and represents interaction between typical anthropogenic sources and natural emitters. Additionally, a source apportioning using multiple regression on absolute principal component scores is performed in order to obtain qualitative information about the impact of the different identified emission sources on the urban environment. 相似文献