Search results for "compensatio"
showing 10 items of 409 documents
Dynamic stabilization of the magnetic field surrounding the neutron electric dipole moment spectrometer at the Paul Scherrer Institute
2014
The Surrounding Field Compensation (SFC) system described in this work is installed around the four-layer Mu-metal magnetic shield of the neutron electric dipole moment spectrometer located at the Paul Scherrer Institute. The SFC system reduces the DC component of the external magnetic field by a factor of about 20. Within a control volume of approximately 2.5m x 2.5m x 3m disturbances of the magnetic field are attenuated by factors of 5 to 50 at a bandwidth from $10^{-3}$ Hz up to 0.5 Hz, which corresponds to integration times longer than several hundreds of seconds and represent the important timescale for the nEDM measurement. These shielding factors apply to random environmental noise f…
Flexible drift-compensation system for precise 3D force mapping in severe drift environments
2011
The acquisition of dense 3D data sets is of great importance, but also a challenge for scanning probe microscopy (SPM). Thermal drift often induces severe distortions in the data, which usually constrains the acquisition of dense data sets to experiments under ultra-high vacuum and low-temperature conditions. Atom tracking is an elegant approach to compensate for thermal drift and to position the microscope tip with highest precision. Here, we present a flexible drift compensation system which can easily be connected to existing SPM hardware. Furthermore, we describe a 3D data acquisition and position correction protocol, which is capable of handling large and non-linear drift as typically …
High resolution Time of Flight determination based on reconfigurable logic devices for future PET/MR systems
2013
Abstract This contribution shows how to perform Time of Flight (TOF) measurements in PET systems using low-cost Field Programmable Gate Array (FPGA) devices with a resolution better of 100 ps. This is achieved with a proper management of the FPGA internal resources and with an extremely careful device calibration process including both temperature and voltage compensation. Preliminary results are reported.
Charge compensation by long-period reconstruction in strongly polar lithium niobate surfaces
2013
The microscopic structure of the polar (000$\overline{1}$) and (0001) surfaces of lithium niobate is investigated by atomic-resolution frequency modulation atomic force microscopy and first-principles calculations. It is found that the surface reconstructs at annealing temperatures sufficiently high to drive off external adsorbates. In particular a ($\sqrt{7}\ifmmode\times\else\texttimes\fi{}\sqrt{7}$)$R$19.1${}^{\ensuremath{\circ}}$ reconstruction is found for the (000$\overline{1}$) surface. Density-functional theory calculations show that---apart from the $(\sqrt{7}\ifmmode\times\else\texttimes\fi{}\sqrt{7})$---a series of adatom-induced surface reconstructions exist that lower the surfa…
Spatio-temporal control of ultra-short pulses by using diffractive optical elements
2012
Diffractive optical elements (DOEs) have shown their applicability to control the spatio-temporal characteristics of ultra-short laser pulses. DOEs can provide high efficiency, compactness, very low material dispersion and, when implemented with spatial light modulators, real-time pulse engineering. In this communication, we report management of temporal and spectral profiles of ultra-short pulses by means of a quasi-direct space-to-time (QDST) pulse shaper. Moreover, we present spatio-temporal control, including dispersion compensation, by DOEs, and applications for activating nonlinear processes. On the other hand, we have achieved complete spatial control of ultra-short pulses, overcomin…
Left-handed metamaterial coatings for subwavelength-resolution imaging
2012
We report on a procedure to improve the resolution of far-field imaging by using a neighboring high-index medium that is coated with a left-handed metamaterial. The resulting plot can also exhibit an enhanced transmission by considering proper conditions to retract backscattering. Based on negative refraction, geometrical aberrations are considered in detail since they may cause a great impact in this sort of diffraction-unlimited imaging by reducing its resolution power. We employ a standard aberration analysis to refine the asymmetric configuration of metamaterial superlenses. We demonstrate that low-order centrosymmetric aberrations can be fully corrected for a given object plane. For su…
Conflict, Evolution, Hegemony, and the Power of the State
2013
In a model of evolution driven by conflict between societies more powerful states have an advantage. When the influence of outsiders is small we show that this results in a tendency to hegemony. In a simple example in which institutions differ in their “exclusiveness” we find that these hegemonies will be inefficiently “extractive” in the sense of having inefficiently high taxes, high compensation for state officials, and low welfare.
Weak and Strong Compensation for the Prioritization of Public Investments: Multidimensional Analysis for Pools
2015
Despite the economic crisis still heavily affecting most of Europe, a possible resumption can be found in the revitalization of public and private investments. These investments should be directed not only towards the strategic areas of infrastructures and production, but also to those which allow for a higher level of the quality of life (sports facilities, parks, etc.). In such cases, the need to balance the reasons of financial sustainability with environmental and social profiles is even more evident. Thus, multicriteria techniques, supporting complex assessments, should be implemented together with a monetary feasibility study (cost-benefit analysis). Multidimensional methods allow for…
Relationship between emotional coping and depressive symptomatology
2021
IntroductionFrom the life cycle perspective, the aging is described as the strengthening of adaptive resources and the capacity for recovery or compensation for losses. These skills are grounded in the coping strategies that individuals apply in order to effectively adapt to diverse situations. Emotion-focused, passive coping strategies are considered to be maladaptive in the long term. These strategies are associated with affective disorders, being these phenomena of great impact in older adults.ObjectivesVerify if there is a relationship between emotion-focused coping strategies and depressive symptomsMethodsThe sample was composed of 418 healthy older adults, aged between 60 and 89 years…
Ventilación asistida vía máscara nasal en pacientes hospitalizados en una sala de neumología por descompensación de su obstrucción crónica al flujo a…
1995
Our aim was to evaluate the efficacy of assisted ventilation through a nasal mask (AVN) in treating chronic obstructive pulmonary disease (COPD) patients who were admitted to a pneumology ward due to decompensation, with PaCO2 > 60 mmHg and pH < 7.35. We studied 13 COPD patients who were first observed for 1-2 days until adaptation and then given 2 daily sessions of AVN lasting 4 hours with double positive pressure (DP90) devices through Sullivan mask with a cannula for hyperoxia. Gasometric readings were recorded, along with subjective assessment of condition and problems with the mask. Gasometric readings were taken as follows: the first upon admission to the ward (AW), the second with AV…