Search results for "Orders of Magnitude"
showing 10 items of 188 documents
Monte Carlo simulation in polymer physics: Some recent developments
1991
The computer simulation of macromolecular materials has to deal with phenomena on length scales from 1A to 100A, as well as with time scales ranging over many orders of magnitude, and thus still presents a challenge. With suitably coarse-grained models which disregard detailed information on chemical structure nevertheless collective phenomena can be described, such as unmixing of polymer blends, mesophase ordering of block-copolymer melts, “blob formation” in semidilute solutions, etc. Simulations of such models provide a sensitive test of approximate theories and give valuable hints for experiments.
New Schemes for the Production and Spectroscopy of Positronium
1989
The rate of positronium formation has been increased by 2–3 orders of magnitude using recently developed accelerator based slow positron sources. This opens the possibility of improvements of precision experiments on the Ps atom as well as new experiments on excited states. First evidence for enhanced metastable Ps formation is presented and future possibilities are discussed.
Novel biosensoric devices based on molecular protein hetero-multilayer films
1997
We have developed a novel concept for the modification of technical surfaces with molecularly well-organized layers of bioorganic components. A molecular construction set has been used to implement this concept which is based on molecularly stratified polyelectrolyte films as a structure decoupling protein layers from solid substrates. Utilizing this technology, one can start from a number of different substrates to obtain the same surface structures, on which protein hetero-multilayer films can be prepared to functionalize the interface for (potentially very different) purposes. We have demonstrated the viability of this concept by constructing a biosensor surface that was characterized by…
PATTERNED LASER CRYSTALLIZATION OF a-Si
2009
PATTERNED LASER CRYSTALLIZATION OF a-SiThin films of amorphous Si on glass were crystallized by pulsed nano- and picosecond lasers. Two methods for creating the desired patterns of crystallized regions were used. In the former, the pattern is produced by a focused laser beam, and in the latter it is made using a prefabricated mask. The electric conductivity of crystallized films increases by more than 4 orders of magnitude in comparison with untreated amorphous films.
Development of a Gas Method for Migration Studies in Fractured and Porous Media.
1992
ABSTRACTA gas method for fast measurements of diffusion properties of porous materials has been developed. Diffusion coefficients in the gas phase are typically four orders of magnitude larger than those in the liquid phase. For samples whose structures do not change much upon drying it is possible to estimate the diffpision properties of the liquid phase when the properties of the gas phase are known. Advantages of the gas method are quick and easy measurements and therefore they can be used to optimize the liquid-phase measurements which may last months or years. For materials with good correlation between the gas and liquid-phase diffusion, the number of liquid phase measurements can be …
An Efficient Wiener Path Integral Technique Formulation for Stochastic Response Determination of Nonlinear MDOF Systems
2015
The recently developed approximate Wiener path integral (WPI) technique for determining the stochastic response of nonlinear/hysteretic multi-degree-of-freedom (MDOF) systems has proven to be reliable and significantly more efficient than a Monte Carlo simulation (MCS) treatment of the problem for low-dimensional systems. Nevertheless, the standard implementation of the WPI technique can be computationally cumbersome for relatively high-dimensional MDOF systems. In this paper, a novel WPI technique formulation/implementation is developed by combining the “localization” capabilities of the WPI solution framework with an appropriately chosen expansion for approximating the system response PDF…
Second- and third-harmonic generation as a local probe for nanocrystal-doped polymer materials with a suppressed optical breakdown threshold
2003
Abstract Second- and third-harmonic generation processes are shown to allow the detection of absorptive agglomerates of nanocrystals in transparent materials and the visualization of optical breakdown in nanocomposite materials. Correlations between laser-induced breakdown and the behavior of the second- and third-harmonic signals produced in SiC/PMMA nanocomposite films are studied. The potential of second- and third-harmonic generation for the on-line visualization of laser breakdown in nanocomposite polymer materials is revealed, with the ablative material removal being monitored by the decay of the second- and third-harmonic signals. The second and third harmonics generated around the o…
Influence of beam conditions and energy for SEE testing
2012
GANIL/Applications industrielles; The effects of heavy-ion test conditions and beam energy on device response are investigated. These effects are illustrated with two types of test vehicles: SRAMs and power MOSFETs. In addition, GEANT4 simulations have also been performed to better understand the results. Testing to high fluence levels is required to detect rare events. This increases the probability of nuclear interactions. This is typically the case for power MOSFETs, which are tested at high fluences for single event burnout or gate rupture detection, and for single-event-upset (SEU) measurement in SRAMs below the direct ionization threshold. Differences between various test conditions (…
Collisional ionization as a sensitive detection scheme in collinear laser-fast-beam spectroscopy
1986
Abstract State-selective collisional ionization of fast atomic beams is used to detect optical pumping. Counting of these ions is superior in sensitivity by several orders of magnitude to the conventional fluorescence detection, provided that the energy levels involved in the optical pumping process are sufficiently well separated. A straightforward application is envisaged in the collinear laser-fast-beam spectroscopy of rare-gas isotopes far from stability of which only very weak beams are available from on-line isotope separators.
Novel mechanism for primordial perturbations in minimal extensions of the Standard Model
2020
Abstract We demonstrate that light spectator fields in their equilibrium can source sizeable CMB anisotropies through modulated reheating even in the absence of direct couplings to the inflaton. The effect arises when the phase space of the inflaton decay is modulated by the spectator which generates masses for the decay products. We call the mechanism indirect modulation and using the stochastic eigenvalue expansion show that it can source perturbations even four orders of magnitude larger than the observed amplitude. Importantly, the indirect mechanism is present in the Standard Model extended with right- handed neutrinos. For a minimally coupled Higgs boson this leads to a novel lower bo…