77 research outputs found

    Potato plant growth acceleration and yield increase after treatment with an amino acid growth stimulant

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    An increase in the productivity of potato plants and natural resistance of tubers to external influences during growth, while preserving the qualitatively new properties of tubers in the process of low-temperature preservation, can be achieved through the effect of bioactive compounds on the metabolism of potato plantsn our work, we used a regulator derived from the hydrolysis of natural collagen down to low molecular weight fractions and pure glycine. The evidence of its effectiveness is based on shortening the growing season and increasing plant productivity as well as the content of bioactive and nutrient compounds in their storage organs, reducing losses during low-temperature preservation caused by natural biological processes, physiological diseases and damage by microorganisms. The paper deals with issues related to the growth and development of potato plants and their storage organs until the growing season is over and a possible increase of potato productivity after the planting material was treated with an amino acid growth regulator

    Optical spectroscopy of the radio pulsar PSR B0656+14

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    We have obtained the spectrum of a middle-aged PSR B0656+14 in the 4300-9000 AA range with the ESO/VLT/FORS2. Preliminary results show that at 4600-7000 AA the spectrum is almost featureless and flat with a spectral index $\alpha_nu ~ -0.2 that undergoes a change to a positive value at longer wavelengths. Combining with available multiwavelength data suggests two wide, red and blue, flux depressions whose frequency ratio is about 2 and which could be the 1st and 2nd harmonics of electron/positron cyclotron absorption formed at magnetic fields ~10^8G in upper magnetosphere of the pulsar.Comment: 4 pages, 4 figures, To appear in Astrophysics and Space Science, Proceedings of "Isolated Neutron Stars: from the Interior to the Surface", eds. D. Page, R. Turolla and S. Zan

    Helium in superstrong magnetic fields

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    We investigate the helium atom embedded in a superstrong magnetic field gamma=100-10000 au. All effects due to the finite nuclear mass for vanishing pseudomomentum are taken into account. The influence and the magnitude of the different finite mass effects are analyzed and discussed. Within our full configuration interaction approach calculations are performed for the magnetic quantum numbers M=0,-1,-2,-3, singlet and triplet states, as well as positive and negative z parities. Up to six excited states for each symmetry are studied. With increasing field strength the number of bound states decreases rapidly and we remain with a comparatively small number of bound states for gamma=10^4 au within the symmetries investigated here.Comment: 16 pages, including 14 eps figures, submitted to Phys. Rev.

    Search for jet extinction in the inclusive jet-pT spectrum from proton-proton collisions at s=8 TeV

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    Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.The first search at the LHC for the extinction of QCD jet production is presented, using data collected with the CMS detector corresponding to an integrated luminosity of 10.7  fb−1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The extinction model studied in this analysis is motivated by the search for signatures of strong gravity at the TeV scale (terascale gravity) and assumes the existence of string couplings in the strong-coupling limit. In this limit, the string model predicts the suppression of all high-transverse-momentum standard model processes, including jet production, beyond a certain energy scale. To test this prediction, the measured transverse-momentum spectrum is compared to the theoretical prediction of the standard model. No significant deficit of events is found at high transverse momentum. A 95% confidence level lower limit of 3.3 TeV is set on the extinction mass scale

    Searches for electroweak neutralino and chargino production in channels with Higgs, Z, and W bosons in pp collisions at 8 TeV

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    Searches for supersymmetry (SUSY) are presented based on the electroweak pair production of neutralinos and charginos, leading to decay channels with Higgs, Z, and W bosons and undetected lightest SUSY particles (LSPs). The data sample corresponds to an integrated luminosity of about 19.5 fb(-1) of proton-proton collisions at a center-of-mass energy of 8 TeV collected in 2012 with the CMS detector at the LHC. The main emphasis is neutralino pair production in which each neutralino decays either to a Higgs boson (h) and an LSP or to a Z boson and an LSP, leading to hh, hZ, and ZZ states with missing transverse energy (E-T(miss)). A second aspect is chargino-neutralino pair production, leading to hW states with E-T(miss). The decays of a Higgs boson to a bottom-quark pair, to a photon pair, and to final states with leptons are considered in conjunction with hadronic and leptonic decay modes of the Z and W bosons. No evidence is found for supersymmetric particles, and 95% confidence level upper limits are evaluated for the respective pair production cross sections and for neutralino and chargino mass values

    Determining the evaporation energies of alkali and alkaline earth metal atoms using field desorption

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    The desorption of cesium and barium atoms from a quasi-spherical nanostructured surface of a field emitter has been studied using the method of field desorption microscopy. The dependences of the desorbing electric field strength on the degree of cesium and barium coating of the rhenium and tungsten field emitter at migration equilibrium are obtained. Migration equilibrium occurs at a certain emitter temperature when, due to the surface diffusion, the concentration of adsorbate is redistributed on various surface areas depending on the local heat of evaporation of adatoms from these areas. It is shown that when the migration equilibrium condition is met on the nanostructured surface of the field emitter, on which there are flat low-index crystal faces with different output work, the desorption has an avalanche-like character with the removal of the entire adsorbate. This behavior of the field desorption is characteristic of atoms of alkaline and alkaline earth metals, associated with a sharper increase in the work function compared with an increase in the evaporation energy of the atom with a decrease in the adsorbate concentration. As a result, the ion desorption energy decreases with an avalanche-like increase in the desorption rate. Taking into account the same desorbing field on all parts of the surface, which follows from the characteristics of Fowler Nordheim, the heat of evaporation of adsorbate atoms on different parts of the surface with different work function is determined within the framework of the image forces model for field desorption

    The effect of the interaction of barium atoms on the surface of the rhenium field emitter on the work function

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    Modification of the emission surface on a nanometer scale during adsorption of barium atoms on the surface of a rhenium field emitter was investigated using field electron and desorption microscopy. Field electronic images of the emitter surface reflecting the localization of barium atoms on the emitter surface, representing the quasi-spherical surface of a rhenium single crystal, were obtained. The influence of the temperature of the emitter with adsorbed barium on the change in the emitter work function is shown. Deposition at room temperature leads to the appearance of a dependence of the work function on the concentration of adsorbate with a minimum in the area of optimal coating. Annealing of the emitter at T = 600 K after deposition of each portion of barium causes the minimum to disappear. After reaching the minimum value (optimal coverage with adsorbed atoms), the work function remains constant with an increase in the number of adsorbed barium atoms on the surface of the emitter. A sharp change in the localization of barium atoms due to a phase transition with the formation of islands in the region of the rhenium face was detected on the field electronic image. The change in the nature of the dependence of the work function is associated with a phase transition in the barium film with the formation of barium islands. The concentration of barium in the islet is constant and corresponds to the optimal coating

    Field desorption of caesium and barium from graphen nanoclueters on the iridium surfaces

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    The features of the field desorption of caesium and barium from the surface of an iridium tip with two-dimensional graphene nanoclusters on the surface are investigated. Both adsorbates are located both on the surface of iridium and carbon clusters, and in the intercalated state under the graphene film in the close packed planes of the iridium crystal. Field desorption proceeds in different ways. With an increase in the intensity of the applied electric field, the pulse removal of the adsorbate from the surface occurs. With further strengthening of the field in the case of caesium, desorption of adsorbate atoms from the intercalated state occurs. Caesium atoms come out from under the film, diffuse onto the surface of the cluster and are desorbed in the ion form. Barium atoms remain under the graphene film until the cluster is destroyed. The difference in the mechanisms of field desorption from graphene clusters is explained by the presence of a second electron on the valence shell of alkali metal atoms, which provides a chemical bond between the adsorbed atoms and the substrate. The only valence electron of alkali metal atoms during adsorption goes into the metal, and provides an electrostatic bond of the adsorbate with the substrate and electrostatic repulsion of the adatoms among themselves

    Initial and post-cryogenic assessment of viability of russian plum cultivars pollen (

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    The viability of pollen of 5 collectible varieties of Russian plum of the Pushkinskiye and Pavlovskiye VIR Laboratories SPB before and after cryopreservation was studied. It was found that a significant factor for the level of pollen viability is “variety” (p=0.07), the factors “cryopreservation” (p=0.457), “year” (p=0.221), as well as the interaction of the factors “variety× cryopreservation” (p=0.172), were not significant at the p<0.05 level of significance. For long-term storage of Russian plum pollen in liquid nitrogen, the year of pollen collection is not a significant factor. For most genotypes, no negative impact of cryoсonservation on pollen viability was revealed. The varieties ‘Aureus’, 'Podarok Sankt-Peterburgu’ and ‘Exotica’ after cryopreservation for 1 year showed a tendency to increase the pollen viability indicators

    Nondestructive monitoring of aircraft composites using terahertz radiation

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    In this paper we consider using the terahertz (THz) time domain spectroscopy (TDS) for non destructive testing and determining the chemical composition of the vanes and rotor-blade spars. A versatile terahertz spectrometer for reflection and transmission has been used for experiments. We consider the features of measured terahertz signal in temporal and spectral domains during propagation through and reflecting from various defects in investigated objects, such as voids and foliation. We discuss requirements are applicable to the setup and are necessary to produce an image of these defects, such as signal-to-noise ratio and a method for registration THz radiation. Obtained results indicated the prospects of the THz TDS method for the inspection of defects and determination of the particularities of chemical composition of aircraft parts
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