RESUMEN
Non-resonant inelastic X-ray scattering of core electrons is a prominent tool for studying site-selective, i.e. momentum-transfer-dependent, shallow absorption edges of liquids and samples under extreme conditions. A bottleneck of the analysis of such spectra is the appropriate subtraction of the underlying background owing to valence and core electron excitations. This background exhibits a strong momentum-transfer dependence ranging from plasmon and particle-hole pair excitations to Compton scattering of core and valence electrons. In this work an algorithm to extract the absorption edges of interest from the superimposed background for a wide range of momentum transfers is presented and discussed for two examples, silicon and the compound silicondioxide.
RESUMEN
X-ray photon-correlation spectroscopy is used to measure the dynamic structure factor f(q,tau) of gold particles moving on the surface of thin polymer films. Above the glass transition of the polymer the peculiar form f(q,tau) approximately exp[-(Gamma tau)(alpha)] is found with 0.7 < alpha < 1.5, depending on sample age and temperature. The relaxation rates Gamma scale linearly with q, excluding a simple Brownian diffusive motion. This type of behavior, already observed in aging bulk soft matter systems, is explained by a power law distribution of particle velocities due to ballistic motion.
Asunto(s)
Oro/química , Modelos Químicos , Nanopartículas/química , Nanopartículas/ultraestructura , Polímeros/química , Espectrometría por Rayos X/métodos , Simulación por Computador , Movimiento (Física) , Propiedades de SuperficieRESUMEN
The tensile strength of preserved tendons was studied in relation with duration and preserving process. Cialite preserved cow-tendons were implanted in rear limbs of rabbit. After 5, 7 and 9 months the transplants could still be identified. They were covered by unreactive fibrous connective tissue, where by adjustant to the connective tissue the transplant was replaced by multicellular growing tissue. In clinical practice preserved tendons were successfully used for ligament-plastic. It is reported on the possibility of use and the results.