TO THE QUESTION OF THE EXISTENCE OF CENTAURS - EVENTS IN COSMIC RAYS

One of the first exotic phenomena observed in the 80s of the last century was an event registered by a calorimetric type installation. In this event, an anomalous relationship was observed between charged and neutral hadrons, arising from the collision of a high-energy particle with a carbon nucleus. In accordance with the principle of isotopic invariance, the number of neutral pions should be equal to the number of charged pions. The event, which was recorded by Japanese physicists, contained only charged peonies with no neutral [1]. This event was named "Centaur". Until now, such events have not been observed in accelerator experiments. The article presents the results of searching for such events in experiments at the DESY HERA collider. For the candidates for Centaur events and for all other events, constructed distributions by the type of fitability of charged tracks in CTD. Since the absence of neutral particles in events is explained by methodological reasons, "Centaur" events were not detected in electron-proton interactions at the ZEUS facility.

Inverse halogen dependence in anion 13C NMR

Halogens cause pronounced and systematic effects on the 13C NMR chemical shift (δ13C) of an adjacent carbon nucleus, usually leading to a decrease in the values across the halogen series....

New Strategy of Synthesis of Peramivir Analogues as Potential Neuraminidase Inhibitors

Highly functionalised potential neuraminidase (NA) inhibitors, analogues of peramivir, were synthesised via a new and versatile method starting from a stereoselective 1,3-dipolar cycloaddition reaction between the nitrile oxide derived from 2-ethylbutanal and the commercially available and inexpensive cyclopentadiene and 1,3-cyclohexadiene, which afforded the isoxazolino-cyclopentene or cyclohexene intermediates, respectively. The subsequent reaction of the C=C bond in different conditions allowed the functionalisation of the five (or six) membered carbon nucleus. Further functionalised derivatives displaying an amino and a hydroxyl group were achieved via the final opening of the isoxazoline ring.

A New Receiver Front-End for Simultaneous Dual-Frequency NMR Applications

To obtain certain information such as metabolic concentrations in neural or muscular tissues and other applications, it is necessary to design nuclear magnetic resonance (NMR) transmitters/receivers capable of operating at multiple frequencies, while maintaining a good performance at each frequencies. We have proposed a new NMR receiver front-end for simultaneous detection of proton and carbon nucleus. The system consists of two reception coils for carbon and hydrogen analysis, a multiband low-noise amplifier (LNA) for increasing the voltage level and a network for passive amplification, noise figure minimization and decreasing mutuality effect between two coils. The proposed coil set was designed, simulated and analyzed and also the signal to noise ratio (SNR) with quality factor have been calculated for it by simulation. The LNA has been designed in a 0.18[Formula: see text][Formula: see text]m CMOS technology and its gains for carbon and proton NMR signals are 45 and 48[Formula: see text]dB, respectively. The input referred noise for both signals is lower than 0.4[Formula: see text]nV/sqrt(Hz) and the power consumption is 4 mA from a single 1.8[Formula: see text]V supply.