Sökresultat

We put forward an approach for the development of a nonlocal density functional by a direct modeling of the shape of exchange-correlation (xc) hole in inhomogeneous systems. The functional is aimed at giving an accurate xc energy and an accurate corresponding xc potential even in difficult near-degeneracy situations such as molecular bond breaking. In particular we demand that: (1) the xc hole pro

TiO2 nanoparticles were in situ generated in one-dimensional poly(methyl methacrylate) PMMA nanohybrid fibers with excellent dispersion by using electrospinning combined with a sol-gel method followed by a mild hydrothermal treatment that preserves the properties of the polymer to the maximum degree. Detailed information of the preparation method, synthesis route, structure and properties of TiO2/

Patterns of feather wear in birds captured in spring have traditionally been analysed to describe the extent of winter moult in long-distance migrants. However, the interpretation of feather wear may be rendered extremely difficult due to long moult periods, by the progress of the season, and by the existence of complex moult patterns. Here, stable isotope analysis is used to determine the origin

Calculations are reported of the nonlinear screening of a proton in an electron gas of densities corresponding to rs=1-6. Results for charge densities and total energies are presented from self-consistent Kohn-Sham ground-state calculations. The results differ markedly from the case of linear screening, particularly at low densities. The occurrence of a bound state around the proton for rs>1.9 ind

Changes in the redox metabolism in the anaerobic, extremely thermophilic, hydrogen-forming bacterium Caldicellulosiruptor saccharolyticus were probed for the first time in vivo using mediated amperometry with ferricyanide as a thermotolerant external mediator. Clear differences in the intracellular electron flow were observed when cells were supplied with different carbon sources. A higher electro

[NiFe] hydrogenases catalyse the reversible conversion of molecular hydrogen to protons and electrons. This seemingly simple reaction has attracted much attention because of the prospective use of H2 as a clean fuel. In this paper, we have studied how H2 binds to the active site of this enzyme. Combined quantum mechanical and molecular mechanics (QM/MM) optimisation was performed to obtain the geo

A molecular motor potentially performing a continuous unidirectional rotation is studied by a multidisciplinary approach including organic synthesis, transient spectroscopy and excited state trajectory calculations. A stereogenic center was introduced in the N-alkylated indanylidene-pyrroline Schiff base framework of a previously investigated light-driven molecular switch in order to achieve the u

Brazil has faced severe droughts in recent decades, significantly affecting agriculture, water supply, and hydropower generation, among other sectors. The Paraná River Basin, a major hub for hydropower, has been particularly affected, posing challenges for water management. To address this, we conducted a study to provide tailored climate information for the Brazilian hydroelectric sector. Given t

Determination of the atomic structure of solid surfaces typically depends on comparison of measured properties with simulations based on hypothesized structural models. For simple structures, the models may be guessed, but for more complex structures there is a need for reliable theory-based search algorithms. So far, such methods have been limited by the combinatorial complexity and computational

Popular Abstract in Swedish Synkrotronstrålning genereras när laddade partiklar som färdas med relativistiska hastigheter böjs av i ett magnetfält. Under accelerationen som böjningen utgör genereras synkrotronstrålning i en smal kon i partikelns framåtriktning. Denna fotonstrålning är intensiv och utgör en användbar prob inom materialforskningen. Genom att belysa material med synkrotronstrålningenWithin research, synchrotron radiation is a highly useful probe for the study of materials, their properties and structures. Currently, no other radiation source allows the combination of high intensity and short wavelengths. The 3rd generation light sources currently in use for the production of synchrotron radiation are however considerable investments: for already existing facilities this makes

In this study, the use of energy carriers based on renewable energy sources in battery-powered electric vehicles (BPEVs), fuel-cell electric vehicles (FCEVs), hybrid electric vehicles (HEVs) and internal combustion engine vehicles (ICEVs) is compared regarding energy efficiency, emission and cost. There is the potential to double the primary energy compared with the current level by utilising vehi

Kinetics of lysine blockage, as an early step of the Maillard reaction, was investigated in commercial skim milk powder to understand the extent of the reaction, specifically after packages are opened and during the subsequent storage. Samples were stored at six conditions including three temperatures (30, 32.5 and 35 °C) and two relative humidities (43% and 52%) for 30 days, the period in which t