Phase Ce

Kammer, H. W., Kressler, H. and Kummerloewe, Ce Phase Behavior of Polymer Blends -Effects of Thermodynamics and Rheology. bl. 106, pp. 31-86. 

Both in the quantum-mechanical and in the classical calculations, only the first return of the electron to the ion has been considered. Due to wave function spreading, the contributions of the longer orbits are suppressed. The most remarkable result of these investigations is the surprisingly high sensitivity of the (pi, p2 )-momentum distribution to variations of the CE phase. In principle, this lends itself to a very precise determination and control of this parameter. 

Speyer JL, Collins JM, Dedrick RL, Brennan ME, Buckpitt AR, Louder H, DeVita VT Jr, Myers CE. Phase I and pharmacological studies of 5-fluorouracil administered intraperitoneally. Cancer Res 1980 40(3) 567-72. 

The Ce02 formation depends closely on the temperature treatment of sample and affect strongly the zero point charge. From the results obtained we can conclude that the addition of a ceria concentration aroimd 2 wt.% lead to an new Ti-O-Ce phase, that contribute to the better performance of the Rh/Ti02 monolithic catalysts for the N2O decomposition reaction. The presence of Ce02 crystal phase is responsible for a decrease in the catalytic activity. 

From a recent compilation of Ce phase diagram data, the binary Ce-Al system at 400-500°C comprises five intermetallic phases yS-CejAl, CeAl, CeAl2, CeAlj, and... 

Fig. 4.2. Low pressure-low temperature region of pseudo-equilibrium phase diagram of cmium. The dashed line in the p-Ce phase region is the extension of the afy phase boundary to lower temperatures and pressures. The letters C.P. mean critical point.

The earliest investigations of the crystal structure of cerium (Hull, 1921) indicated that cerium had both a face centered cubic (fee) and a hexagonal close-packed (hep with cl a = 1.62) structure at room temperature and one atmosphere. Subsequent studies revealed only the fee phase with a ==5.15 A, which today is identified as y-Ce (see table 4.2 for additional crystallographic data). About 25 years ago the a-Ce phase was identified by X-ray methods at both high pressure and room temperature (Lawson and Tang, 1949) and at low temperature and atmospheric pressure (Schuck and Sturdivant, 1950) to have a fee structure but with a = 4.83 A. The a phase, with a volume about 17% less than that of y-Ce, is also known as the collapsed fee phase. This large volume difference is also observed in dilatometric and volumetric studies of the a y transformation. 

A simple close-packed hexagonal structure has been reported for cerium at ambient temperature and pressure (Hull, 1921) and above 5 GPa pressure and 298 K (MeWhan, 1970). The former probably had observed the dhep 8-Ce phase along with fee y-Ce in an impure cerium sample and incorrectly indexed the non-cubic phase as simple hep. The high pressure X-ray pattern observed by MeWhan was also indexed by Ellinger and Zachariasen (1974) to be orthorhombic (see section 2.2). 

The Sc-Ce phase diagram has been determined by Naumkin et al. (1964). Gschneidner (1975) and Gschneidner and Calderwood (1982b, 1986a) corrected only the values of the melting and allotropic transition temperatures of the pure components to conform with the accepted values. The bcc phases of Sc and Ce are completely miscible in each other. The LT modifications of Sc and Ce dissolve about 12 and about 17at.% of Ce and Se, respectively. 

The next class of irregular f elements includes at ambient pressure Ce in the a-Ce phase and all the light actinides from Th to Pu, which are characterized by 4f and 5f bands or bonding f contributions, respectively. In this respect is is not clear whether Ac and Th should also be included in this class however, from the close similarity of the EOS data for Th in the r/ versus r, plot presented in fig. 12 in comparison with the... 

No Hall effect measurements on Ce metal are reported after 1963 (Gschneidner and Smoluchowski 1963) and there are no detailed investigations of the pure a- and y-Ce phase showing the extraordinary Hall effect. Such studies would be very interesting. 

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