Viscosity modeling for ionic liquid solutions by Eyring-Wilson equation

A semi-theoretical model based on the classical Eyring’s mixture viscosity equation and the Wilson activity coefficient equation is presented for correlating the viscosity of ionic liquids with solvent systems. The accuracy of the proposed model was verified by comparing calculated and experimental viscosity values from literatures for 49mixtures with total 1560 data points. The results show that the equation similar to the Wilson activity coefficient equation can be well applied to describe the non-ideal term in the Eyring’s mixture viscosity equation. The model has a relatively simple mathematical form and can be easily incorporated into process simulation software

Dual-band circularly-polarized shared-aperture array for C/X-Band satellite communications

A novel method of achieving a single-feed circularly-polarized (CP) microstrip antenna with both broad impedance bandwidth and axial ratio (AR) bandwidth is presented. The CP characteristics are generated by employing a resonator to excite the two orthogonal modes of the patch via two coupling paths and the required 90 o phase difference is achieved by using the different orders of the two paths. The presented method, instead of conventional methods that power dividers and phase delay lines are usually required, not only significantly enhances the bandwidths of the antenna, but also results in a compact feed, reduced loss and high gain. Based on this method, a dual-band shared-aperture CP array antenna is implemented for C/X-band satellite communications. The antenna aperture includes a 2 × 2 array at C-band and a 4 ×4 array at X-band. To accommodate the C/X-band elements into the same aperture while achieving a good isolation between them, the C-band circular patches are etched at the four corners. The measured results agree well with the simulations, showing a wide impedance bandwidth of 21% and 21.2% at C-and X-band, respectively. The C-and X-band 3-dB AR bandwidths are 13.2% and 12.8%. The array also exhibits a high aperture efficiency of over 55%, low side-lobe (C-band: −12.5 dB; X-band: −15 dB) and high gain (C-band: 14.5 dBic; X-band: 17.5 dBic)

{4-Bromo-2-[3-(diethyl­ammonio)propyl­imino­meth­yl]phenolato}diiodidozinc(II) methanol solvate

In the title complex, [ZnI2(C14H21BrN2O)]·CH3OH, the asymmetric unit consists of a mononuclear zinc(II) complex mol­ecule and a methanol solvent mol­ecule. The compound was derived from the zwitterionic form of the Schiff base 4-bromo-2-[3-(diethyl­amino)propyl­imino­meth­yl]phenol. The ZnII atom is four-coordinated by the imine N and phenolate O atoms of the Schiff base ligand and by two iodide ions in a distorted tetra­hedral coordination. In the crystal structure, the methanol mol­ecules are linked to the Schiff base mol­ecules through N—H⋯O and O—H⋯O hydrogen bonds. One I atom is disordered over two positions in a 0.702 (19):0.298 (19) ratio