查看更多>>摘要：Cubic perovskites and inverse perovskites have been largely studied in the last years due to their wide interesting physical and chemical properties. However, a little works has been done on their thermal properties, mechanical properties such as strength, stiffness, corrosion resistance. In this work, we would like to demonstrate that perovskites and inverse perovskites could be used to design high-strength ultra-hard coatings materials by fabricating a layered structure of two materials with the same crystal structure. Comparatively to other authors, in our works we have used a multivariate technique based on principal component analysis (PCA) and the partial least square regression (PLS-R). We demonstrate that the score plots allow us to clearly identify the more interesting compounds comparatively one to the other. On the other hand, we have proposed an approach based on the Koehler method in order to predict which perovskites and inverse perovskites have the potential to achieve high hardness and fracture toughness for use as a thermal barrier coating (TBC). We propose 10 among the 129 perovskites and inverse perovskites studied have the potential to be used as thermal barrier coatings. These findings could be used to develop novel multilayer ultra-hard coating materials based on perovskites.
查看更多>>摘要：We propose a self-contained theoretical methodology to predict the pH effects on the molecular electronic spectra in aqueous solution, combining our recently developed the configuration-selection (CS) constant-pH (CpH) simulation (CS-CpH) method with quantum mechanics/molecular mechanics (QM/MM) method. By computationally sampling many protonation state transitions by CS-CpH simulations and estimating the electronic energies by QM/MM calculations, we can obtain the theoretical description of the pH dependent electronic spectra. As an example, we applied the present methodology to para-nitrophenol (pNP) in aqueous solution, and demonstrated that the method could successfully reproduce the electronic transition energies and the isosbestic point.
查看更多>>摘要：Temperature dependence of 1H nuclear magnetic resonance spin-lattice relaxation time T1 of (ImH)2KCo(CN)6, ImH+: imidazolium cation, is reported. The asymmetric T1 minimum observed in intermediate-temperature phase between 198 and 112 K is analyzed assuming the Cole-Davidson distribution of correlation time. Temperature dependences of 14N nuclear quadrupole resonance frequencies and spin-lattice relaxation times are also reported. The phase transitions at 198 and 112 K are shown to be of second and first order, respectively. The 14N relaxation is shown to be governed by the electric field gradient fluctuation due to the in-plane reorientational motion of the imidazolium cations.
NSTL
Elsevier