A simple optical device for measuring free surface deformations of nontransparent liquids

In this paper, a novel optical device for measuring the deformation of liquid free surfaces is presented. The device employs a laser beam, which can be focused on any chosen location on the free surface. The key measurement is of the intensity of the beam reflected from a location on the free surface where the deformation exhibits a local extremum. The optics of the device is so designed as to measure a maximum intensity when the distance between the focusing lens and the selected point on the free surface is equal to the focal length, thus enabling a height measurement. The device is tested in ferrofluid pools where the height of the spikes of the normal field instability is measured. The simplicity of the suggested technique enables the fabrication of a quite cheap device for measuring surface deformation of nontransparent liquids, which provides good accuracy and reproducibility.     

Robust Grouped Variable Selection Using Distributionally Robust Optimization

Journal of Optimization Theory and Applications - We propose a distributionally robust optimization formulation with a Wasserstein-based uncertainty set for selecting grouped variables under...     

Photoacoustic spectrum of a new, 12-fold-coordinated Ho(III) hydrazone complex

A new, 12-fold-coordinated holmium(III) compound [Ho(NO₃)₃(PBH)₂]NO₃ · 1.5H₂O has been prepared and studied with high-resolution photoacoustic spectrometry (PAS). The spectroscopic parameters of the obtained photoacoustic lines attributed to the f–f transitions were analyzed and compared with the parameters for a similar 10-fold-coordinated holmium(III) complex [Ho(NO₃)₂(PicBH)₂]. Computer fitting of the obtained spectra allowed decomposing them into Gaussian components and calculating the spectral parameters of each transition. It was found that of the five observed f–f transitions, the ⁵I₈ → ⁵G₆ and the ⁵I₈ → ⁵G₃ transitions were found to be the most sensitive to the change of ligand coordination. The charge transfer π → π¹ and n → π¹ transitions registered in the UV part of the photoacoustic spectrum showed a significant variation due to the change in the coordination number and the shift of ligands toward greater wavenumbers.     

Focused grid‐based resampling for protein docking and mapping

The fast Fourier transform (FFT) sampling algorithm has been used with success in application to protein‐protein docking and for protein mapping, the latter docking a variety of small organic molecules for the identification of binding hot spots on the target protein. Here we explore the local rather than global usage of the FFT sampling approach in docking applications. If the global FFT based search yields a near‐native cluster of docked structures for a protein complex, then focused resampling of the cluster generally leads to a substantial increase in the number of conformations close to the native structure. In protein mapping, focused resampling of the selected hot spot regions generally reveals further hot spots that, while not as strong as the primary hot spots, also contribute to ligand binding. The detection of additional ligand binding regions is shown by the improved overlap between hot spots and bound ligands. © 2016 Wiley Periodicals, Inc.     

Electron paramagnetic resonance and magnetic susceptibility of rare-earth hydrazone compounds

The magnetic properties of the rare earth molecular compounds with hydrazone ligands containing Nd³⁺, Gd³⁺, and Yb³⁺ have been investigated by electron paramagnetic resonance (EPR) and magnetization measurements. For the Gd-compound, partially resolved fine structure due to Gd³⁺ and exchange narrowing effects at low temperatures are observed in the EPR spectra, suggesting, consistent with the EPR and dc magnetic susceptibility, weak antiferromagnetic exchange interactions. Paramagnetic behavior sustained down to low temperatures is derived for Yb³⁺ ions, whereas substantial ferromagnetic exchange coupling is inferred for the lighter Nd³⁺ ions, indicating significant variations of the exchange integrals along the lanthanide series. Received 29 April 2002 Published online 31 July 2002