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Stephan Weinbruch Michael Wentzel Manfred Kluckner Peter Hoffmann Hugo M. Ortner 《Mikrochimica acta》1997,125(1-4):137-141
In this paper procedures for the characterization of individual aerosol particles by element mapping in the electron microprobe are presented. The number, size and qualitative chemical composition of particles is derived from a combination of secondary or backscattered electron images and element distribution maps. Accuracy of the size distribution and reliability of the qualitative analysis procedure were checked with silicate samples. In order to obtain a semi-quantitative estimate of the chemical composition of individual particles the count rates taken from element distribution maps are corrected for matrix and geometric effects using particle ZAF procedures.Dedicated to Professor Dr. rer. nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthday 相似文献
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Urate oxidase from Asperigillus flavus has been shown to be a model protein for studying the effects of polyethylene glycol (PEG) on the crystallization of large proteins. Extensive experimental studies based on small angle x-ray scattering [Vivares and Bonnete, J. Phys. Chem. B 108, 6498 (2004)] have determined the effects of salt, pH, temperature, and most importantly PEG on the crystallization of this protein. Recently, some aspects of the phase diagram have also been determined experimentally. In this paper, we use Monte Carlo techniques to predict the phase diagram for urate oxidase in solution with PEG, including the liquid-liquid and liquid-solid coexistence curves. The model used includes an electrostatic interaction, van der Waals attraction, and a polymer-induced depletion interaction [Vivares et al., Eur. Phys. J. E 9, 15 (2002)]. Results from the simulation are compared with experimental results. 相似文献
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The relaxation of linear poly(styrene sulfonate) chains in a swollen poly(acrylamide) network is investigated by birefringence
measurements. After a stepwise deformation of the network relaxation occurs, because the linear chains are initially deformed
as well, but diffuse into an isotropic conformation via the reptation mechanism. The course of the birefringence with time
agrees essentially with what follows from the reptation model. It could be shown that the relaxation time varies approximately
with the third power of the molar mass of the enclosed molecules when networks of sufficiently high network density are used.
On the other hand, the dependence of the relaxation time on network density or degree of swelling, respectively, seems to
be much stronger than what is expected from theory.
Received: 9 September 1996 Accepted: 25 November 1996 相似文献
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