Search results for "Density distribution"
showing 10 items of 13 documents
Correlations between density distributions, optical spectra, and ion species in a hydrogen plasma (invited)
2016
An experimental study of plasma distributions in a 2.45 GHz hydrogen discharge operated at 100 Hz repetition rate is presented. Ultrafast photography, time integrated visible light emission spectra, time resolved Balmer-alpha emission, time resolved Fulcher Band emission, ion species mass spectra, and time resolved ion species fraction measurements have been implemented as diagnostic tools in a broad range of plasma conditions. Results of plasma distributions and optical emissions correlated with H + , H + 2 , and H + 3 ion currents by using a Wien filter system with optical observation capability are reported. The magnetic field distribution and strength is found as the most critical facto…
X-ray investigations of the superstructure of collagen
2008
When compared with results from humid fibers, characteristic changes of the SAXS-pattern taken from dried collagen fibers have been observed. The average lateral width of the various reflexions increases with the order of reflexion whereby a fluctuation is superimposed, the type of which cannot easily be related to the reflexion order. Moreover, each of the reflexions is obviously laterally split into three components. An explanation of these characteristics can be given with the aid of a distinct model, assuming that the collagen fibrils have definitely varying diameters along their axis, whereby paracrystalline distortions appear, represented by nematic fluctuations. Additionally, there i…
Molecular Electron Density Theory: A Modern View of Reactivity in Organic Chemistry
2016
A new theory for the study of the reactivity in Organic Chemistry, named Molecular Electron Density Theory (MEDT), is proposed herein. MEDT is based on the idea that while the electron density distribution at the ground state is responsible for physical and chemical molecular properties, as proposed by the Density Functional Theory (DFT), the capability for changes in electron density is responsible for molecular reactivity. Within MEDT, the reactivity in Organic Chemistry is studied through a rigorous quantum chemical analysis of the changes of the electron density as well as the energies associated with these changes along the reaction path in order to understand experimental outcomes. St…
Muon multiplicities measured using an underground cosmic-ray array
2016
EMMA (Experiment with Multi-Muon Array) is an underground detector array designed for cosmic-ray composition studies around the knee energy (or similar to 1 - 10 PeV). It operates at the shallow depth in the Pyhasalmi mine, Finland. The array consists of eleven independent detector stations similar to 15 m(2) each. Currently seven stations are connected to the DAQ and the rest will be connected within the next few months. EMMA will determine the multiplicity, the lateral density distribution and the arrival direction of high-energy muons event by event. The preliminary estimates concerning its performance together with an example of measured muon multiplicities are presented.
Dependence of two-proton radioactivity on nuclear pairing models
2017
Sensitivity of two-proton emitting decay to nuclear pairing correlation is discussed within a time-dependent three-body model. We focus on the $^6$Be nucleus assuming $\alpha + p + p$ configuration, and its decay process is described as a time-evolution of the three-body resonance state. For a proton-proton subsystem, a schematic density-dependent contact (SDDC) pairing model is employed. From the time-dependent calculation, we observed the exponential decay rule of a two-proton emission. It is shown that the density dependence does not play a major role in determining the decay width, which can be controlled only by the asymptotic strength of the pairing interaction. This asymptotic pairin…
Validation of lung densitometry threshold at CT for the distinction between senile lung and emphysema in elderly subjects
2015
Background and Aims. An ageing lung is characterised by distal airspace enlargement without alveolar wall destruction: therefore the anatomical distinction between senile lung and emphysema is clear-cut. In clinical settings the definition of precise boundaries between normalcy and pathology is more difficult with the risk of overdiagnosis. CT is an important diagnostic advancement in the field of COPD. Most methods for the evaluation of emphysema are based on the detection and measurement of areas characterised by a density level below a threshold assumed to characterize parenchymal destruction. Methods. Our retrospective study included 47 healthy subjects (65-91 years), 36 never smokers a…
The electronion scattering experiment ELISe at the International Facility for Antiproton and Ion Research (FAIR) - A conceptual design study
2011
The electronion scattering experiment ELISe is part of the installations envisaged at the new experimental storage ring at the International Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany. It offers an unique opportunity to use electrons as probe in investigations of the structure of exotic nuclei. The conceptual design and the scientific challenges of ELISe are presented. © 2011 Elsevier B.V. All rights reserved.
Underground multi-muon experiment EMMA
2011
EMMA is a new experiment designed for cosmic- ray composition studies around the knee energy operating at the shallow depth underground in the Pyh¨ asalmi mine, Fin- land. The array has sufficient coverage and resolution to de- termine the multiplicity, the lateral density distribution and the arrival direction of high-energy muons on an event by event basis. Preliminary results on the muon multiplicity ex- tracted using one detector station of the array are presented.
Central depression in nuclear density and its consequences for the shell structure of superheavy nuclei
2006
The influence of the central depression in the density distribution of spherical superheavy nuclei on the shell structure is studied within the relativistic mean field theory. Large depression leads to the shell gaps at the proton Z=120 and neutron N=172 numbers, while flatter density distribution favors N=184 for neutrons and leads to the appearance of a Z=126 shell gap and to the decrease of the size of the Z=120 shell gap. The correlations between the magic shell gaps and the magnitude of central depression are discussed for relativistic and non-relativistic mean field theories.
A novel numerical meshless approach for electric potential estimation in transcranial stimulation
2015
In this paper, a first application of the method of fundamental solutions in estimating the electric potential and the spatial current density distribution in the brain due to transcranial stimulation, is presented. The coupled boundary value p roblems for the electric potential are solved in a meshless way, so avoiding the use of grid based numerical methods. A multi-spherical geometry is considered and numerical results are discussed.