A hybrid foldamer with unique architecture from conformationally constrained aliphatic-aromatic amino acid conjugate

In this paper, we describe the design and synthesis of a novel hybrid foldamer, derived from a conformationally constrained aliphatic-aromatic amino acid conjugate that adopts a well-defined, compact, three-dimensional structure, governed by a combined conformational restriction imposed by the individual amino acids from which the foldamer is composed. Conformational investigations confirmed the prevalence of a unique doubly bent conformation for the foldamer, in both solid and solution states, as evidenced from single crystal X-ray and 2D NOESY studies, respectively. The findings suggest that constrained aliphatic-aromatic amino acid conjugates offer new avenues for the de novo design of hybrid foldamers with distinctive structural architectures. Furthermore, the de novo design strategy disclosed herein has the potential for significantly augmenting the ‘tool-box’ of the modern day peptidomimetic chemist, as well as providing a novel approach to the field of rational design.     

Microstructure-controlled enhancement of magnetoimpedance in nanocrystalline FeSiNbBCu alloys

Rapidly solidified amorphous Fe_68.5Si_18.5Nb₃B₉Cu₁ ribbon has been subjected to heat treatment at a temperature of 550 °C for different time periods. All the annealed ribbons show the precipitation of nanocrystalline Fe₃Si phase from the amorphous phase. The estimated crystallite size from X-ray diffraction peak analysis was in the range of 15-25 nm. While the surface studies confirm the presence of a distribution of spherical nanostructures in amorphous matrix. Both magnetoimpedance and longitudinal permeability ratios are found to increase with annealing time, and attain a maximum value for 60 min annealed ribbon and decrease on further increase in the annealing time. The enhanced magnetic properties and magnetoimpedance on suitable heat treatment is attributed to the change of magnetic parameters such as anisotropy and magnetostriction, due to change in microstructure. Analysis of permeability and impedance data taken under similar conditions suggests a strong correlation between them.     

Magnetic properties of Ho1−xMmxCo2 (x=0, 0.1, 0.2, 0.3 and 0.4) alloys and their hydrides

The influence of Mm (Mm=mischmetal) substitution and hydrogen absorption on the magnetic properties of Ho_1−xMm_xCo₂ (x=0, 0.1, 0.2, 0.3 and 0.4) alloys have been determined through the temperature dependence of ac susceptibility and thermopower measurements. The changes in magnetic-ordering temperature of Ho_1−xMm_xCo₂ alloys have been explained based on the dilution of the magnetic ions and weakening of 4f–3d exchange interactions. The gradual disappearance of the magnetic transition temperature upon increasing hydrogen concentration (y) has been interpreted by the lattice expansion and charge transfer between absorbed hydrogen and 3d-band of Ho_1−xMm_xCo₂.     

Interaction of two parallel plane jets of different velocities

The interaction of two parallel plane jets of different velocities is studied by flow visualization and PIV measurement to examine the influence of velocity ratio on the development ofjets in the initial region. It is found that the parallel plane jets develop toward the high velocity side and the jet width is reduced with a decrease in the jet velocity ratio. Corresponding to the variation of mean velocity field to the velocity ratio, the magnitudes of turbulence intensities, Reynolds stress and static pressure are weakened in the merging region of the jets and their peak locations of the properties are shifted to the high velocity side. These results indicate that the interaction of two parallel jets is weakened with a decrease in the velocity ratio of the jets.