Phase Microstructure Characterization Research Articles

In meso crystallogenesis. Compatibility of the lipid cubic phase with the synthetic digitonin analogue, glyco-diosgenin.

Digitonin has long been used as a mild detergent for extracting proteins from membranes for structure and function studies. As supplied commercially, digitonin is inhomogeneous and requires lengthy pre-treatment for reliable downstream use. Glyco-diosgenin (GDN) is a recently introduced synthetic surfactant with features that mimic digitonin. It is available in homogeneously pure form. GDN is proving to be a useful detergent, particularly in the area of single-particle cryo-electron microscopic studies of membrane integral proteins. With a view to using it as a detergent for crystallization trials by the in meso or lipid cubic phase method, it was important to establish the carrying capacity of the cubic mesophase for GDN. This was quantified in the current study using small-angle X-ray scattering for mesophase identification and phase microstructure characterization as a function of temperature and GDN concentration. The data show that the lipid cubic phase formed by hydrated monoolein tolerates GDN to concentrations orders of magnitude in excess of those used for membrane protein studies. Thus, having GDN in a typical membrane protein preparation should not deter use of the in meso method for crystallogenesis.

Thermodynamics Analysis of Multiple Microelements' Coupling Behavior in High Fatigue Resistance 50CrVA Spring Steel with Nanoparticles.

Solid solution and coupling precipitation behavior of multiple microelements in 50CrVA spring steel under different temperatures were analyzed based on thermodynamics. Quantitative relationships between the multiple microelements’ contents and secondary phases, and their effects on fatigue life, were systematically studied in conjunction with the secondary phase microstructure characterization using scanning and transmission electron microscopy, etc. The solid solution contents of different microelements decreased as the temperature decreased, especially N and Ti, but the number of compounds gradually increased when the temperature decreased. Carbonitride constitutional liquation occurred in 50CrVA-S1# spring steel-containing microparticles, and without carbonitrides, constitutional liquation occurred in 50CrVA-S2# spring steel-containing nanoparticles. The experimental results indicate that the fatigue life reduces by about an order of magnitude when the secondary phase size changes from nanometers to microns, and the corresponding relationship among multiple microelements, microstructure of secondary phases, and fatigue life, was established in this spring steel.

Nano and Microstructural Characterization of Phases and Interfaces of Portlant Cement Mortar Using High Resolution Microscopy

Nano and Microstructural Characterization of Phases and Interfaces of Portlant Cement Mortar Using High Resolution Microscopy