Temperature dependence of the probability of "small heating" and total losses of ucns on the surface of fomblin oils of different molecular mass

We measured the temperature dependence of the probability of small heating and total losses of UCNs on the PFPE Fomblin Y surface with various molecular masses Mw=2800, 3300, 6500 amu in the temperature range of 100-300 K. The probability of small heating sharply decreases with increasing Mw and decreasing temperature. The probability of total loss weakly decreases with decreasing temperature and takes the minimum value at Mw=3300 amu. As this oil provides a homogeneous surface with minimal probabilities of small heating and total losses of UCNs, it is the preferred candidate for experiments on measuring the neutron lifetime

Phase distortions of attosecond pulses produced by resonance-enhanced high harmonic generation

Resonant enhancement of high harmonic generation can be obtained in plasmas containing ions with strong radiative transitions resonant with harmonic orders. The mechanism for this enhancement is still debated. We perform the first temporal characterization of the attosecond emission from a tin plasma under near-resonant conditions for two different resonance detunings. We show that the resonance considerably changes the relative phase of neighbouring harmonics. For very small detunings, their phase locking may even be lost, evidencing strong phase distortions in the emission process and a modified attosecond structure. These features are well reproduced by our simulations, allowing their interpretation in terms of the phase of the recombination dipole moment

GRANIT project: a trap for gravitational quantum states of UCN

Previous studies of gravitationally bound states of ultracold neutrons showed the quantization of energy levels, and confirmed quantum mechanical predictions for the average size of the two lowest energy states wave functions. Improvements in position-like measurements can increase the accuracy by an order of magnitude only. We therefore develop another approach, consisting in accurate measurements of the energy levels. The GRANIT experiment is devoted to the study of resonant transitions between quantum states induced by an oscillating perturbation. According to Heisenberg's uncertainty relations, the accuracy of measurement of the energy levels is limited by the time available to perform the transitions. Thus, trapping quantum states will be necessary, and each source of losses has to be controlled in order to maximize the lifetime of the states. We discuss the general principles of transitions between quantum states, and consider the main systematical losses of neutrons in a trap.Comment: presented in ISINN 15 seminar, Dubn

Tritium Distribution in 4-0ctene· Prepared by Catalytic Hydrogenation

In orur work on hydrogen isotope effects we needed a symmetrical olefin specifically labeled on the d61Uble bond wi,th tI\u27itium. The simplest way to achieve this seemed to be the preparatiion of an acetylene and the subsequent catalytic reduction with tritium gas to the corresponding olefin. 4-0ctyne was therefore prepaired from n-propyl bromide and d:irsodium acetylide in liquid ammonia by a procedure which was found to· be more practical than the published 101I1es1• 2• 4-0cty.ne was then ireduced wirthout solvent in the presence of Lindlarr catalyst Wlith tritium gas which was produced by ele~trolysis of tritilated sulfuriic acid. The distilled product was pure 4--0eterne as shown by vaipor phase chromatography

RAILWAY NATURAL INDUSTRIAL COMPLEXES AND THEIR IMPACT ON WATERBODIES

The paper aims to investigate objects located in railway natural industrial complexes, e.g. the Kuybyshevskaya Railway within the boundaries of Samara region. The authors analyse its following characteristic properties: geometric (proximity to water bodies); intercepted (crossings with bridges or waterbodies); watercut (proximity to subsurface water outlets and high groundwater); hilly-mountainous terrain (washouts and washaways); violation of surface (water drainage from the walls, washaways of flood-prone slopes). The researchers studied a schematic map of the Kuybyshevskaya Railway and came to the conclusion that there is a considerable number of railways crossings with water objects in Samara region, Ulyanovsk region and the Republic of Tatarstan. Some of these railways crossings are located in close proximity to waterbodies. The average value of the crossings is 0.549 km for every 1 km, i.e. approximately every 500 m railway tracks cross at least one water object. It means that there is a surface run-off coming from railroad tracks and near-by territories into a waterbody every 500 m. Systematic monitoring of water pollution is performed by a considerable number (up to 20) of gauging stations located within all railroad tracks in Samara region

Yield losses in blackleg of canola and pyraclostrobin sensitivity in populations of Leptosphaeria maculans

Non-Peer ReviewedBlackleg of canola (Brassica napus L.), caused by Leptosphaeria maculans (Desm.) Ces.& de Not., is an important disease worldwide. In Canada, blackleg is managed mainly by the cultivation of resistant or moderately resistant canola hybrids and fungicide application. A field experiment was conducted in central Alberta to determine the relationship between blackleg severity and yield in two moderately resistant hybrids 73-15RR and 1950RR. Seed yield per plant was found to decrease as a consequence of L. maculans infection, with regression analysis showing that the relationship between yield and disease severity was best explained by second degree quadratic equations. Sensitivity to the fungicide pyraclostrobin, a strobilurin that is commonly applied as a foliar and seed treatment for blackleg and other diseases, was evaluated in 12 and 250 isolates of L. maculans collected in Alberta in 2011 and 2016. The half-maximal effective concentration (EC50) of pyraclostrobin was determined, and two discriminatory doses of the fungicide were used to identify highly insensitive isolates in the collection. The mean EC50 value was significantly higher for the isolates collected in 2016 (0.28 mg L-1) versus those collected in 2011 (0.07 mg L-1). Nonetheless, while all isolates were still sensitive to pyraclostrobin, the increase in mean EC50 observed in the more recent L. maculans collections suggests that proper fungicide stewardship is warranted

Облачное хранилище

Несмотря на многочисленные преимущества облачного хранилища, защита данных по-прежнему является уязвимостью. В этой статье рассматриваются несколько способов защиты личных данных на облачном сервере. Данные могут быть защищены от изменений, посторонними лицами с помощью облачной системы хранения, где данные шифруются и поиск осуществляется по ключевому слову. В статье исследуется надежная и безопасная схема облачного хранилища с использованием нескольких обслуживающих компаний, и описывается архитектура облачной системы хранения на основе атрибутов с безопасным происхождением.Despite the many benefits of cloud storage, data protection is still a vulnerability. In this article, several ways of protection personal data on a cloud server are conceded. Data can be protected from alteration by unauthorized people using a cloud storage system, where data is encrypted and searched for using a keyword. In this article, a reliable and secure cloud storage schema using multiple service providers is examined and the system architecture of an attribute-based cloud storage system with secure provenance is described

Diode effect in magnetic tunnel junctions

The influence on the I-V characteristics and tunnel magnetoresistance (TMR), of impurities embedded into the insulating barrier I separating the two ferromagnetic electrodes F of a magnetic tunnel junction, was theoretically investigated. When the energy of the electron's bound state at the impurity site is close to the Fermi energy, it is shown that the current and TMR are strongly enhanced in the vicinity of the impurity. If the position of the impurity inside the barrier is asymmetric, e.g. closer to one of the interfaces F/I, the I-V characteristic exhibits a quasidiode behavior. The case of a single impurity and of a random distribution of impurities within a plane were both studied.Comment: 8 pages, 5 figure