Effects well-known

Approximately 1 g polymer and 0aQ6 M Cr(acac). were dissolved in CDCl. to prepare solutions for ySi and JC NMR spectroscopy. NMR spectra were run on a Varian XL-200 FT-NMR instrument. To aid in obtaining quantitative data, the solution was doped with 0.06 M chromium acetylacetonate [Cr(acac) )] to remove possible signal artifacts resulting from long spin-lattice relaxation times (T s) and tt> nucleay Overhauser effect, well-known features associated with 3Si and JC NMR spectroscopy. This permits quantitative signal acquisition. From the literature (16) and additional work done in this laboratory, it was expected that Cr(acac) would be an inert species. A solution of HMDZ (2.04 g, 12.67 mmole),... 

It was noted in the early study by Pankove et al. (1985) that the hydrogen vibrational frequency appropriate to the H—B pair was in the range consistent with a hydrogen bonded to a silicon but was in fact somewhat smaller than that expected for an isolated hydrogen connected to a single silicon. Generally, if an atom becomes more confined, the frequency is expected to increase. It was suggested that the frequency reduction was due to a three-body effect well known in molecules. 

However, the influence of magnetic and nonmagnetic impurities appears to be opposite for the SC and SDW critical temperatures (Tconset and T rder, respectively). While influence of nonmagnetic impurities at depression of Tynsef jn thg system is only negligible but in the SDW system normal impurities (say, Zn) produce the pair-breaking effect (for electron-hole pairs), the effect well known in excitonic semimetals. Such behavior is in fact... 

Variations in Dq have also indicated more subtle phenomena whereby the extent of tt bonding from metal to ligand, Y, in a series of complexes of octahedral microsymmetry, MX4Y2, is a function of the nature of X (38). Here Dq reflects the synergic effect well-known in metal carbonyl chemistry. 

This Morse potential implies that the average X - Y distance increases with temperature, an effect well known as dilatation. This is because the average distance of <2s in the M,th excited state increases with (Figure 4.1), and an increase of temperature populates levels with greater N. Such a dilatation is not accounted for in the harmonic approximation where the average distance remains equal to Qq in all states. The levels of the Hamiltonian with potential energy defined in eq. (4.6) are now... 

Another class of interacting forces are the so-called chemical forces (Prausnitz 1969). In contrast to the physical forces these forces are counterbalanced. Typical examples are the covalent bonds, electron donor-acceptor interactions, acidic solute - basic solvent interactions. Association and solvatation are effects well-known to every chemist. 

On the basis of the IR data, the general consensus is that when minerals exhibit 100% flotability, several types of chemisorbed oleate as well as precipitated calcium oleate are present at the surface, in agreement with the initial hypothesis of Peck [425]. However, there is controversy concerning the assignment of the adsorption bands of adsorbed oleate and, hence, the structure of surface species. It stems from the strong dependence of the oleate-calcium coordination on the deposition and precipitation conditions-an effect well known for L monolayers and LB films of alkanoates [426]. The amount of oleate adsorbed on a fluorite slab, as measured by IR spectroscopy, is quite different than that for fine fluorite particles [412]. For the slab, there exists an adsorption saturation point, but for fine particles, the amount of adsorbed oleate increases with concentration, although the concentration dependence of the amount of oleate in the... 

The chelate effect, well known in coordination chemistry, can be used to rationalize the high degree of dissociation in PEG despite its low dielectric constant. At low concentrations of NiBr2 and CoBr2, the conductivity seems to be mainly due to motion of the Br anions. As the salt concentration increases, the solution viscosity increases and the molar... 

The asymptotic shape of the dependence Uq = (pCf) (Fig. 8.7a) demonstrated the existence of an isotropy frequency /q at which Ae returns to zero and above which it can assume negative values. The piesence of this effect, well known... 

The changes in the fracture surface energy with the age of concrete are displayed in Fig. A. These changes resemble those in the compressive strength due to age of the material, an effect well-known in concrete technology. 

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