[en] In this device the ambient background noise is unceasingly measured by means of piezoelectric pick-ups and is compared against a reference voltage in a comparator that controls the measuring instrument

[en] We present a simplified method for the extraction of meaningful signals from Hanford and Livingston 32 second data for the GW150914 event made publicly available by the LIGO collaboration, and demonstrate its ability to reproduce the LIGO collaboration's own results quantitatively given the assumption that all narrow peaks in the power spectrum are a consequence of physically uninteresting signals and can be removed. After the clipping of these peaks and return to the time domain, the GW150914 event is readily distinguished from broadband background noise. This simple technique allows us to identify the GW150914 event without any assumption regarding its physical origin and with minimal assumptions regarding its shape. We also confirm that the LIGO GW150914 event is uniquely correlated in the Hanford and Livingston detectors for the full 4096 second data at the level of 6–7 σ with a temporal displacement of τ = 6.9 ± 0.4 ms. We have also identified a few events that are morphologically close to GW150914 but less strongly cross correlated with it.

No abstract available

[en] The design criteria of the first fully integrated charge preamplifier completely based on HEMTs, together with few preliminary tests of the circuit, has been already presented by the authors [G. Bertuccio et al., Nucl. Instr. and Meth. A 338 (1994) 582]. In the previous work the circuit was tested directly on wafer using coplanar probes. In this Letter we present a more accurate characterisation of the amplifier, including its noise and linearity. The results here presented have been obtained with the amplifier diced and bonded in a suitable package for low noise applications. (orig.)

[en] We demonstrate the effect of coherence resonance in a heterogeneous array of coupled Fitz Hugh--Nagumo neurons. It is shown that coupling of such elements leads to a significantly stronger coherence compared to that of a single element. We report nontrivial effects of parameter heterogeneity and spatial independence of noise on array-enhanced coherence resonance; especially, we find that (i) the coherence increases as spatial correlation of the noise decreases, and (ii) inhomogeneity in the parameters of the array enhances the coherence. Our results have the implication that generic heterogeneity and background noise can play a constructive role to enhance the time precision of firing in neural systems

[en] Synchronous detection offers an especially powerful instrument of investigation. It enables a signal to be extracted from the noise by narrowing of the analysis band at the expense of the examination time, and in this sense constitutes a very narrow filter synchronised externally on the signal to be examined. It is phase-sensitive, a great advantage in the determination of transfer functions

No abstract available

[en] This paper presents a study concerning the formulation of sensitivity limits in radioactivity analysis using gamma-ray spectrometer. Expressions for practical evaluation of the detection level (SD) and the detection limit (LD) are given. The detection level is defined as a detection criterion (a posteriori) and the detection limit is defined either a posteriori, for undetected radionuclides, or a priori, for the weakest activity which can be detected in the analysis conditions. Given expressions use only the total background at the place of gamma-ray photopeak and the Full Width at Half Maximum (FWHM) for this peak. The main parameters occurring in these limits are studied and some recommendations are given. The use of these limits in some expressions of radioactivity analysis results (single measure, sum, mean) is also indicated

[en] The paper deals with the technique for measuring charged particle beam parameters and can be used for development of devices for studying surface properties of solids by the methods of charged particle secondary emission in superhigh vacuum. The purpose of the invention is to increase sensitivity of an energy analyzer. It can be attained by reducing the effect of parasitic currents from the electrodes on the results of measurements. For this purpose the energy analyzer is provided with a metal screen covering the external electrode representing a grid; here the screen is electrically connected with the common bus. The background may be reduced 10 times in this case

[en] In this paper, a novel approach for generating flat optical frequency comb (OFC) based on externally injected gain-switched distributed feedback (DFB) semiconductor laser is proposed and experimentally demonstrated. In the proposed system, the flatness, the number of OFC spectral lines, and the spectral line to background noise ratio can be tuned to their optimized values by adjusting the current of the modulation signal, the injection ratio and the detuning frequency. Since the frequency of the modulation signal decides the frequency spacing of the output spectral lines, OFC spectral lines of different spacing can be achieved. In the experiment, 10 spectral lines with 1.5 dB power variation are demonstrated to verify the proposed approach. In addition, the expansion of the spectral line is investigated. (letter)