The change trends of the glass structure of the three component svstem As Ge Te were studied by the method EXAFS, based on the phase diagram works of this system. That provides scientific basis for the preparation and the application of the above mentioned system.

The structral morphology of metal catalyst Ni in the synthetic diamond was measured by using the fluorecence EXAFS technique. The nickle impurities found exist as fee structure, which is similar to the pure metal Ni. The results obtained from the amount of C atoms coordinated surround Ni and the dilation of Ni-Ni distance show about 9 at-% carbon in the metal Ni matrix which is much more than the limit of earbon solubility 2.7 at-% in metal Ni at normal pressure. The coordination number of Ni in diamond found is less than that in pure metal. This shows that the nickle in the diamond distributes as small particles with dimension about 20?.

The surface dispersion of bifunctional NiO-MoO3/gamma-alumina catalysts prepared by different procedures was studied with Ni-K EKAFS spectroscopy. The contents of NiO (13.6%) and MoO3, (10.5%) were the same in the three samples, which were a little higher than the monolayer dispersion capacity of each component on The dispersion temperature was 450 degrees C, The sample impregnated with NiO first shows that the NiO is monolayer-dispersed on gamma-Al2O3 surface and the outer layer is MoO3. The sample impregnated with MoO3 first shows that there is crystalline state NiO in this sample and the inner layer is MoO3, and the outer layer is NiO, There is strong interaction between MoO3 and v gamma-Al2O3 which affects the dispersion of NiO on the surface. The sample impregnated with NIO and MoO3, simultaneously shows that the Ni is not dieperaed in the form of NiO hut another compound on the surface.

On the basis of EXAFS analysis of the ternary system of Na2OAl2O3GeO2 glasses, it is confirmed that a coordination change occurs for the Ge ions from 4 to 6 as in binary germanate glasses and it is found that the variation of the sixfold Ge ion fraction with composition corresponds well to that of physical properties such as density. The anomalous composition dependence of the properties of sodium aluminogermanate glasses is explained as a result of the formation and disappearance of denser groups containing GeO6 octahedra.

EXAFS spectroscopy has been used to investigate the dispersion of NiO onto the surface of gamma-Al2O3. The comparison of the Fourier transformed EXAFS modulations of 7, 13, 18, 26, 35 wt% Ni/gamma-Al2O3 and 13, 26 wt% Ni/a-Al2O3 suggests that NiO can disperse as a monolayer onto the surface of -gamma Al2O3. The Ni-O coordination distance which is near the Ni-O distance in NiO crystal suggests that the Ni ion interacts strongly with the oxygen on the gamma-Al2O3 surface.

The effect on amplitude of EXAFS from harmonic caused by high order diffraction of crystal monochromator is discussed. The general expression and calculated results are presented. It is shown that the harmornic decreases the amplitude of EXAFS and the amount of decrease is related to such factors as intensity ratio of harmonic to fundamental, thickness and absorption coefficient of specimen. K edge EXAFS spectra with and without harmonic for different thickness copper foils have been measured respectively, and the distortion of single shell EXAFS amplitudes have been extracted. The measured results are consistent with calculated ones. Consequently, a method to correct the harmonic effect on EXAFS amplitude is proposed.

The structurs and phase content in industrial catalyst NiO/alpha-Al2O3 before and after reaction were studied by EXAFS. Part of NiO in the catalyst is reduced to Ni phase. The reducing amount is different for the samples located at different height of the reactor. The phase contents of NiO and Ni were measured and the local structure around Ni atoms was measured by using mixed phase EXAFS ana lysis method. The results show that the average coordination number of Ni atom in Ni phase is decreased compared with metal Ni. This is caused by more Ni atoms located at surface state. The dimension of Ni cluster is estimated, Meanwhile there is no obvious change of the environment of Ni atom in NiO phase before and after reaction.

A method to calculate the harmonic effect on EXAFS amplitude for poly-element systems is given. Results calculated and measured are presented. They are consistent with each other.

The energy aberration of crystal monochromator in the case of continuous X-ray spectrum, for instance EXAFS, has been discussed. Based on the fact that the intensity of continuous X-ray varies slowly with the energy and can be treated as a constant, we propose a method of calculating average resolution for flat crystal and the Johann and Johansson arrangement. We have also pointed out some inappropriate points in analyses on the reflect geometry of Johann arrangement described in previous publications. It is shown that Johann crystal can provide a better resolution than that commonly believed.