Družice Suomi-NPP je prototypem nové generace meteorologických družic JPSS. Jejím hlavním přístrojem je VIIRS, navazující na radiometry AVHRR a MODIS družic NOAA/POES, resp. Terra/Aqua. Jeho zcela novou součástí je vysoce citlivý přístroj DNB (Day/Night Band) určený primárně pro noční snímání Země a její atmosféry. Příspěvek dokumentuje citlivost přístroje DNB na několika vybraných příkladech., The Suomi/NPP satellite is a prototype of a new generation of weather satellites, JPSS. Its main instrument is VIIRS, a follow-up instrument of the NOA/POES and Metop AVHRR radiometer, and of the Terra/Aqua MODIS instrument. One of its main advances is a brand new Day/Night Band (DNB), designed primarily for night-time imaging of the Earth and its atmosphere. This short article documents the ultimate DNB low-light sensitivity of several selected cases., Martin Setvák., and Obsahuje seznam literatury
The key role of the vagus nerves in the reflex control of breathing is generally accepted. Cardiopulmonary vagal receptors and their afferent connection with the medullary respiratory centers secures the proper regulatory feedback. Section of the vagi at the midcervical level interrupts primary vagal reflexes and those due to activation of lung afferents by neuroactive substances. In this context the present review focuses on the reflex contribution of the inferior (nodose) vagal ganglia to the respiratory pattern, considering that this structure contains perikarya of vagal afferent neurons which house neurotransmitters, neuropeptides and neurochemical substances. In experimental animals with removed sensory input from the lungs (midcervical vagotomy) the following evidence was reported. Transient respiratory suppression in the form of apnoea, occuring after systemic injection of serotonin, adenosine triphosphate and anandamide (N-arachidonoyl-ethanolamine-endogenous cannabinoid neurotransmitter), which was abrogated by nodose ganglionectomy. Preserved nodose-NTS connection conditioned respiratory depression affecting the timing component of the breathing pattern evoked by N-6-cyclopentyl-adenosine (CPA) and inhibition of both respiratory constituents induced by NPY. Stimulatory effect of NPY13-36 on tidal volume required nodosal connection. The cardiovascular effects of majority of the tested substances occurred beyond the nodose ganglia (with exclusion of serotonin and anandamide)., K. Kaczyńska, M. Szereda-Przestaszewska., and Obsahuje seznam literatury
Gearboxes and similar machines containing rotating parts are complex systems with complicated structure and couplings. Generally they can be decomposed into more simple subsystems. These subsystems are usually rotating shafts with gears joined
by gear couplings and housing coupled with rotating shafts by bearings. The paper is aimed at the mathematical modelling of gearboxes with spur helical gears considered including their interior rotating shaft system and housing. The used bearing model
respects real number of rolling elements and roller contact forces acting between the journals and the outer housing. The model of a complete gearbox is created using the modal synthesis method. The kinematic transmission errors in gear couplings are viewed as sources of excitation. Vibration and noise analysis of the gearbox housing is performed by means of the created model. Four types of objective functions suitable for optimization from the radiated noise point of view are proposed. The presented methodology is applied to the simple test-gearbox. and Obsahuje seznam literatury
Silicon photomultiplier (SiPM) detectors, also called multipixel photon counters (MPPC), are introduced together with their main characteristics. The focus is given on the timing performance of SiPMs, which is important for the Cherenkov time-of-flight applications, where the SiPMs provide time resolution of the 10 ps order. The time performance is, naturally, influenced by the readout electronic noise. A method for the evaluation of the noise contribution using a Monte Carlo simulation combined with the laboratory measurements is presented and demonstrated on an example of STMicroelectronics NRD09_1 and FBK SiPM-NUV3S SiPMs. The noise contribution to the time resolution depends on the SiPM pulse amplitude A as 1/A. and Článek představuje SiPM detektory, též nazývané MPPC, a jejich základní charakteristiky. Důraz je kladen na využití při měření času, což je důležité např. pro čerenkovské detektory pro měření času průletu, které při využití SiPM dosahují časového rozlišení řádově 10 ps. Přesnost měření času je ovlivněna šumem produkovaným vyčítací elektronikou. Článek představuje metodu pro vyhodnocení vlivu šumu využívající Monte Carlo simulaci v kombinaci s daty naměřenými v laboratoři. Metoda je demonstrována na příkladu dvou SiPM: STMicroelectronics NRD09_1 a FBK SiPM-NUV3S. Obě SiPM vykazují závislost příspěvku šumu k časovému rozlišení na amplitudě SiPM pulzu A ve tvaru 1/A.
This article describes a technique for noise reduction of the differential bearings. Noise is excited by the mechanical looseness of the system and by the vibrations of the engine. The mathematical model enables the optimization of the radial stiffness of the differential bearings. A test rig has been designed for the simulation of the phenomenon outside the vehicle. Analytical software has been created that is capable of classifying the types of noise from the measured data. The optimal solution is tested on the rig at the end, thus proving that the technique works. and Obsahuje seznam literatury