Scientific Highlights
CCN formation mechanism in lower troposphere needs revision
Atmospheric aerosols exert an important influence on climate1 through their effects on stratiform cloud albedo and lifetime and the invigoration of convective storms. Model calculations suggest that almost half of the global cloud condensation nuclei in the atmospheric boundary layer may originate from the nucleation of aerosols from trace condensable vapours, although the sensitivity of the number of cloud condensation nuclei to changes of nucleation rate may be small. Despite extensive research, fundamental questions remain about the nucleation rate of sulphuric acid particles and the mechanisms responsible, including the roles of galactic cosmic rays and other chemical species such as ammonia. Here we present the first results from the CLOUD experiment at CERN.
Investigation of a new method for the diagnosis of cancer in breast tissue
Collaboration between research, hospital and industry aimed at transferring innovative procedure into daily practice.
X-Ray Tomography of Water in Operating Fuel Cell
Polymer electrolyte fuel cells (PEFC) convert the chemical energy of hydrogen with a high efficiency (40-70 %) directly into electricity. The product of the overall reaction is water, produced at the cathode of the cell. The interaction of liquid water with the porous structures of the cell is one of the mechanisms in the PEFC that are commonly believed to be key for further optimization with regard to performance, durability and cost.
Non-thermal melting of a charge density wave
We use time-resolved optical reflectivity and x-ray diffraction with femtosecond resolution to study the dynamics of the structural order parameter of the charge density wave phase in TiSe2. We find that the energy density required to melt the charge density wave nonthermally is substantially lower than that required for thermal suppression and is comparable to the charge density wave condensation energy.
PSI sets world record with 1.4 MW proton beam
The highest average power proton beam in the world was produced on 20th of June in the 590 MeV cyclotron at Paul Scherrer Institut. Extremely low beam losses achieved in this 35 years old veteran cyclotron allowed PSI team of accelerator scientists and engineers to put 1.4 MW beam of protons onto the muon and neutron spallation targets. This beam is used to produce the brightest beam of muons in the world, as well as supply neutrons for the spallation source SINQ.
Gas uptake and chemical aging of semisolid organic aerosol particles
Organic substances can adopt an amorphous solid or semisolid state, influencing the rate of heterogeneous reactions and multiphase processes in atmospheric aerosols. Here we demonstrate how molecular diffusion in the condensed phase affects the gas uptake and chemical transformation of semisolid organic particles. Flow tube experiments show that the ozone uptake and oxidative aging of amorphous protein is kinetically limited by bulk diffusion.
Observation of Orbital Currents in CuO
Although high-temperature (Tc) superconductivity was discovered in the cuprates 25 years ago, there is still no consensus on its microscopic origin.
X-ray methods help to understand brain disorders better
An international team of researchers from Denmark, Germany, Switzerland and France has developed a new method for making detailed X-ray images of brain tissue, which has been used to make the myelin sheaths of nerve fibres visible. Damage to these protective sheaths can lead to various disorders, such as multiple sclerosis. The facility for creating these images of the protective sheaths of nerve cells is being operated at the Swiss Light Source (SLS), at the Paul Scherrer Institute.
The electron torus can help us to understand high-temperature superconductors
Paul Scherrer Institute researchers prove, for the first time, the existence of toroidal currents in solids
The role of long-lived reactive oxygen intermediates in the reaction of ozone with aerosol particles
The heterogeneous reactions of ozone with aerosol particles are of central importance to air quality. They are studied extensively, but the molecular mechanisms and kinetics remain unresolved. Based on new experimental data and calculations, we show that long-lived reactive oxygen intermediates (ROIs) are formed. The chemical lifetime of these intermediates exceeds 100 seconds, which is much longer than the surface residence time of molecular ozone (~ ns).