Progressive transition

Burch and Flambard (113) have recently studied the H2 chemisorption capacities and CO/H2 activities of Ni on titania catalysts. They attributed the enhancement of the catalytic activities for the CO/H2 reaction (after activation in H2 at 450°C) to an interfacial metal-support interaction (IFMSI). This interaction is between large particles of Ni and reduced titanium ions the Ti3+ is promoted by hydrogen spillover from Ni to the support, as pictured in Fig. 8. The IFMSI state differs from the SMSI state since hydrogen still chemisorbs in a normal way however, if the activation temperature is raised to 650°C, both the CO/H2 activity and the hydrogen chemisorption are suppressed. They define this condition as a total SMSI state. Between the temperature limits, they assumed a progressive transition from IFMSI to SMSI. Such an intermediate continuous sequence had been... 

API this ensures a smooth and progressive transition between OASIS3 and OASIS4. 

The structural transition from inverted to normal micellar structure occurs around 0.8 to 0.7 water mass fraction. It is obviously a progressive transition. The microstructure in this region is not yet well established. The ultracentrifuge study has shown that the inverted micellar structure may exist persistently down to 0.8 water mass fraction. But the quasielastic light scattering has detected the trace of normal micellar structure as low as 0.7 water mass fraction (5). 

These metals have been described as transition elements, but from a structural point of view they display in many respects the characteristics associated with the series of representative elements discussed above. We have seen in this series a progressive transition from molecular to truly metallic structures, an element in the nth group showing a tendency to assume a structure in which each atom is covalently bound to (8—n) close neighbours. We would thus expect the elements of group z to have structures in which each atom is 6-co-ordinated, and in mercury we find just such a structure in its simplest... 

It is clear from these data that in the temperature range 320-392 °C an intermediate degree of order prevails and that as T is raised there is a progressive transition from the tetragonal superstructure towards the cubic arrangement of the disordered solid solution. 

Southern Italy. There is a pronounced northward decrease in He/ He ratios between the Aeolian Islands of southern Italy and the region of Mt. Vesuvius known as the Campanian Magmatic Province or the Neopolitan volcanic region. Mt. Etna on Sicily can be included in this trend as recent work (e.g., Schiano et al. 2001) indicates a progressive transition from a plume-related to a typical island-arc source for this volcano. The trend or step function in the helium isotope systematics of southern Italy was first pointed out by Sano et al. (1989) and ascribed to shallow crustal contamination effects. However, subsequent work (Marty et al. 1994) has shown the combined He-O-Sr-C isotope systematics are consistent with the progressive involvement of Africa continental crust which has been subducted beneath the southern Tyrrhenian Sea. The influence of the African plate increases in a northerly direction (Marty et al. 1994)—towards Mt. Vesuvius (see data of Graham et al. 1993) and possibly as far north as the Roman and South Tuscany volcanic provinces (see Tedesco 1997). 

Looking back on a decade of experimental and theoretical activity on the nature of excess electron states in liquids, we see a progressive transition from the early quantum-mechanical description of the electron as a polaron, dressed in the polarization field of the dielectric continuum, toward more molecular models. As the boundary of the dielectric continuum receded in order to permit varying geometries of short range, discrete liquid structure to provide an effective electron-molecule trapping... 

Niaz, M. (1995). Progressive transitions from algorithmic to conceptual understanding in student ability to solve chemistry problems A Lakatosian interpretation. Science Education, 79, 19-36. 

X-Ray Photoelectron Spectroscopy (XPS) XPS is a surface chemical analysis technique based on the photoelectric effect, which describes the phenomenon of the ejection of electrons when photons with sufficient energy impinge upon a surface. Due to the characteristic binding energy of each element, the peaks in the resultant spectrum provide information on the chemical state and composition of the surface atoms. For the analysis of Pd nanostructures, XPS has been used primarily to examine the valent states of Pd [74, 80]. Tabuani and colleagues conducted an experiment in which they monitored the reduction of Pd to Pd by XPS, and observed a progressive transition of Pd (337.5 and 342.8eV) to Pd (336.0 and 341.3 eV) [80]. 

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