Hierarchical machine learning of potential energy surfaces.

We present hierarchical machine learning (hML) of highly accurate potential energy surfaces (PESs). Our scheme is based on adding predictions of multiple Δ-machine learning models trained on energies and energy corrections calculated with a hierarchy of quantum chemical methods. Our (semi-)automatic procedure determines the optimal training set size and composition of each constituent machine learning model, simultaneously minimizing the computational effort necessary to achieve the required accuracy of the hML PES.

Factors Influencing Male Involvement in Family Planning in Ntchisi District, Malawi - A Qualitative Study.

Malawi is among countries with the highest maternal mortality ratio (MMR) and fertility rate (FR) in Africa, among others caused by an unmet need for family planning (FP). In Malawi, FP is seen as a women's domain and because of this, male involvement in FP remains lower than wanted. This study aimed to explore influencing factors of male involvement in FP.

Thermochemical Stability and Friction Properties of Soft Organosilica Networks for Solid Lubrication.

In view of their possible application as high temperature solid lubricants, the tribological and thermochemical properties of several organosilica networks were investigated over a range of temperatures between 25 and 580 °C. Organosilica networks, obtained from monomers with terminal and bridging organic groups, were synthesized by a sol-gel process. The influence of carbon content, crosslink density, rotational freedom of incorporated hydrocarbon groups, and network connectivity on the high temperature friction properties of the polymer was studied for condensed materials from silicon alkoxide precursors with terminating organic groups, i.

Influence of Monomer Connectivity, Network Flexibility, and Hydrophobicity on the Hydrothermal Stability of Organosilicas.

It is generally assumed that the hydrothermal stability of organically modified silica networks is promoted by high monomer connectivity, network flexibility, and the presence of hydrophobic groups in the network. In this study a range of organosilica compositions is synthesized to explore the extent to which these factors play a role in the hydrothermal dissolution of these materials. Compositions were synthesized from hexafunctional organically bridged silsesquioxanes (OR)Si-R-Si(OR) (R = -CH-, -CH-, -CH-, -CH-, -p-CH-; R = -CH, -CH), tetrafunctional (OEt)Si(CH)-CH-Si(CH)(OEt) and Si(OEt), trifunctional silsesquioxanes R'-Si(OMe) (R'=CH, n-CH, cyclo-CH, phenyl), and bifunctional Si(i-CH)(OMe).

Atomically defined templates for epitaxial growth of complex oxide thin films.

Atomically defined substrate surfaces are prerequisite for the epitaxial growth of complex oxide thin films. In this protocol, two approaches to obtain such surfaces are described. The first approach is the preparation of single terminated perovskite SrTiO3 (001) and DyScO3 (110) substrates.