Search results for "control systems"
showing 10 items of 590 documents
Polarographic and voltammetric methods for the determination of elements
1978
Measurements of the correlations between current, voltage and time, when microelectrodes are used, yield qualitative and quantitative information on the elemental composition of the solution investigated, if the method of measurement is properly chosen. Instrumental development today makes it possible, even at electrodes which make measurement difficult, such as the classical dropping mercury electrode, to obtain more reliable information on detection limits and number of elements detectable, by taking into account the functional interdependence of interference parameters and signal generation. Simultaneous determination of several components is possible, especially with non-linear a. c. po…
Imaging quality of multifocal intraocular lenses: automated assessment setup
2012
[EN] Purpose: A new technique for the assessment of the optical quality of multifocal intraocular lenses (MIOLs) under monochromatic and polychromatic illumination is presented. Methods: The system provides, in a totally automated procedure, the modulation transfer function (MTF) of the lens under test for different axial positions of the object. The artificial eye admits different artificial corneas, to optimise the axial resolution in the sampling of the MTF of the MIOL under test, and different pupils, to test the dependence of the optical performance of the MIOL on the eye pupil diameter. Results: The performance and sensitivity of the apparatus is tested with different commercial MIOLs…
Molecular Sensors for Moisture Detection by Mössbauer Spectroscopy
2002
A parameter of importance in various industrial and commercial applications is sensitivity to moisture. A new class of molecular sensors which enable the qualitative and quantitative determination of air moisture (high selectivity and sensitivity) by application of Mossbauer spectroscopy as the probe technique has been investigated. The electronic properties of the iron-containing sensor depend upon the presence of moisture which is taken up by it and this process is accompanied by a change in electronic spin ground state which can be detected by Mossbauer spectroscopy. The sensor is suitable for in-field and industrial application using the recently developed Mossbauer spectrometer MIMOS I…
Problems Involved in the Measurement of Microcirculation by Means of Microelectrodes
1973
Until now, the interpretation of local wash-out curves, measured by means of microelectrodes and using hydrogen as diffusible indicator, is an unsettled problem. It has been shown, that even the simultaneous measurement by means of a surface-multiwire-Pt-microelectrode at the isolated and hemoglobin-free perfused rat liver yields different wash-out curves (4). These differences occur with regard to the height of the curves as well as to the moment, when the maximum of the indicator’s concentration is seen by the microelectrode. Fig.1 represents four simultaneously recorded curves. The difference in sensitivity of each micro-electrode has been compensated by a computer. The fast curve corres…
Brain sensitivity to print emerges when children learn letter–speech sound correspondences
2010
The acquisition of reading skills is a major landmark process in a human's cognitive development. On the neural level, a new functional network develops during this time, as children typically learn to associate the well-known sounds of their spoken language with unfamiliar characters in alphabetic languages and finally access the meaning of written words, allowing for later reading. A critical component of the mature reading network located in the left occipito-temporal cortex, termed the “visual word-form system” (VWFS), exhibits print-sensitive activation in readers. When and how the sensitivity of the VWFS to print comes about remains an open question. In this study, we demonstrate the…
Capillary electrophoresis enhanced by automatic two-way background correction using cubic smoothing splines and multivariate data analysis applied to…
2005
Mixtures of the surfactant classes coconut diethanolamide, cocamido propyl betaine and alkylbenzene sulfonate were separated by capillary electrophoresis in several media containing organic solvents and anionic solvophobic agents. Good resolution between both the surfactant classes and the homologues within the classes was achieved in a BGE containing 80 mM borate buffer of pH 8.5, 20% n-propanol and 40 mM sodium deoxycholate. Full resolution, assistance in peak assignment to the classes (including the recognition of solutes not belonging to the classes), and improvement of the signal-to-noise ratio was achieved by multivariate data analysis of the time-wavelength electropherograms. Cubic s…
Statistical sensitivity of the nEDM apparatus at PSI to n − n′ oscillations
2018
The neutron and its hypothetical mirror counterpart, a sterile state degenerate in mass, could spontaneously mix in a process much faster than the neutron β-decay. Two groups have performed a series of experiments in search of neutron – mirror-neutron (n − n′) oscillations. They reported no evidence, thereby setting stringent limits on the oscillation time τnn′. Later, these data sets have been further analyzed by Berezhiani et al.(2009–2017), and signals, compatible with n − n′ oscillations in the presence of mirror magnetic fields, have been reported. The Neutron Electric Dipole Moment Collaboration based at the Paul Scherrer Institute performed a new series of experiments to further test…
Robust regulation with an H<inf>&#x221E;</inf> constrain for linear two-time scale systems
2010
In this paper, the problem of robust multi-objective control design with an H ∞ constrain is studied for a class of linear two-time scale systems. The design is based on a new modelling approach under the assumption of norm-boundedness of the fast dynamics. In this method, a portion of the fast dynamics is treated as a norm-bounded perturbation in the design by its maximum possible gain. In this view, the problem of robust multi-objective control design is performed only for the certain dynamics of the two-time scale system, whose order is less than that of the original system. One illustrative example is used to demonstrate the validity of the proposed approach.
Shell-model calculation of isospin-symmetry breaking correction to superallowed Fermi beta-decay
2016
We investigate the radial-overlap part of the isospin-symmetry breaking correction to superallowed $0^+\to 0^+$-decay using the shell-model approach similar to that of Refs. [1, 2]. The 8 sd-shell emitters with masses between $A=22$ and $A=38$ have been re-examined. The Fermi matrix element is evaluated with realistic spherical single-particle wave functions, obtained from spherical Woods-Saxon (WS) or Hartree-Fock (HF) potentials, fine-tuned to reproduce the experimental data on charge radii and separation energies for nuclei of interest. The elaborated adjustment procedure removes any sensitivity of the correction to a specific parametrisation of the WS potential or to various versions of…
Testing microscopically derived descriptions of nuclear collectivity: Coulomb excitation of Mg-22
2018
Many-body nuclear theory utilizing microscopic or chiral potentials has developed to the point that collectivity might be dealt with in an {\it ab initio} framework without the use of effective charges; for example with the proper evolution of operators, or alternatively, through the use of an appropriate and manageable subset of particle-hole excitations. We present a precise determination of $E2$ strength in $^{22}$Mg and its mirror $^{22}$Ne by Coulomb excitation, allowing for rigorous comparisons with theory. No-core symplectic shell-model calculations were performed and agree with the new $B(E2)$ values while in-medium similarity-renormalization-group calculations consistently underpre…