Search results for "stopping"
showing 5 items of 55 documents
Atoms embedded in an electron gas: Phase shifts and cross sections
1983
The Fermi-level scattering phase shifts and the transport cross sections are reported for atoms embedded in a homogeneous electron gas. The applications of the results are discussed, using the electronic stopping power for slow ions and impurity resistivity as examples. Peer reviewed
Early virologic response with pegylated interferons
2004
Abstract Recently, 12-week evaluation of viral response has been recommended as a means of reducing antiviral treatment morbidity and costs. The development of early stopping rules relies on an important assumption: rules must minimise discontinuation of treatment in patients who might ultimately respond after completion of the full course of therapy. Minimising loss of potential responders is the most important clinical goal in defining an early stopping rule because it provides the most sustained virological responders. This definition of the rule relies on maximising the negative predictive value. Conversely, rules that select patients based on optimising the positive predictive value pr…
Energeettisten protonien jarruuntuminen nestemäisessä vedessä
2011
Tämän työn tarkoituksena oli mitata protonien jarruuntumiskyky nestemäisessä vedessä energia-alueella 4 - 20 MeV. Työssä käytettiin micro channel plate -pohjaisia lentoaikailmaisimia. Lopputulosten suhteelliset virheet vaihtelivat välillä 2,0 - 16,5 % mediaanin ollessa 4,2 % ja keskiarvon 5,3 %. Saadut tulokset olivat hyvässä sopusoinnussa ICRU:n raportin numero 49 antamien simuloitujen arvojen kanssa. Energialtaan 4 - 16 MeV protonien mitatut jarruuntumiskyvyt poikkesivat noin yhden prosentin tai vähemmän simuloiduista arvoista. Energia-alueella 16 - 20 MeV protonien mitatut jarruuntumiskyvyt olivat noin 4 - 8 % suuremmat kuin ICRU:n antamat simuloidut arvot. Mitattuja arvoja verrattiin my…
Particle radiation in microelectronics
2012
The unavoidable presence of particle radiation in space and on the ground combined with constantly evolving technology necessitates a deep understanding of the basic mechanisms underlying radiation effects in materials and electronic devices. This thesis provides an overview of the different radiation environments, with a review of the interaction mechanisms between energetic particles and matter. In this work a new semi-empirical model for estimating the electronic stopping force of solids for heavy ions is introduced. Radiation effects occurring in microelectronics due to particle radiation are also discussed with a brief introduction to radiation hardness assurance (RHA) testing of elect…
Comparison of impact characteristics of different ice hockey arena dasher boards
2012
During last years the incidence and severity of ice hockey related concussions have been increased and, hence, something should be done to stop this growth. The main aim of this study was to find out how dasher board materials and structures affect impact characteristics and, thereby, the risk of concussions. The measurements were divided into two parts; in the first part, the physiological characteristics of body checks were determined in real game measurements, and the second part, consisted of simulation of body checks in the laboratory. High speed cameras and accelerometers were used to collect data. More flexible protective shielding material (dasher board B) resulted in lower peak for…