The structures of various multilayer assemblies of cadmium salts of pure and mixed fatty acids have been studied using the x-ray diffraction technique. Model calculations of diffraction patterns for each assembly have indicated that each is an actual reproduction of the designed structure with the chain lengths of composite molecules being invariant.

We theoretically study packaging-ejection phase transitions of a flexible polymer chain, translocating through a spherical cavity. Based on the Flory model for coil-globule transitions of a single flexible polymer, we derive the free energy of the polymer chain through a spherical cavity. Depending on the size of the cavity, the attractive interaction between the polymer and cavity, solvent quality, and the length of the polymer chain, we find continuous and discontinuous phase transitions between a packaged state and an ejected one of the polymer chain. These results suggest a possibility of the control of DNA packing and ejection. We also perform a Monte Carlo simulation to confirm the theoretical results.

An improvement of spatial resolution of m-XRF by using a thin metal filter was investigated. The size of the x-ray beam focused by the polycapillary x-ray lens depended on the energy of the characteristic x-rays. Original spot sizes at the focal point were 48 µm for CrKa, 41 µm for NiKa, and 28 µm for MoKa, respectively. To make the x-ray beam size small, Ti-Cu thin foil was placed between the output of the lens and the focal point as a metal filter to reduce the continuous x-rays. Finally, the x-ray microbeam size was improved to 30 µm by applying a filter. Clear 2D mapping images of Cr, Fe, and Ni in 300-mesh stainless steel could be obtained by applying this filter.

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