•H absorption in R2Fe17-H (200–250 °C) contains the regions with constant ΔHabs.•The enthalpies of H adsorption/desorption are temperature-dependent.•Enthalpies of H absorption/desorption by R2Fe17 ...decrease in a sequence Nd-Sm-Ho.
For the first time, the interaction of magnetic materials R2Fe17 (R = Nd, Sm, Ho) with hydrogen at 200 and 250 °C and a hydrogen pressure of up to 50 atm was studied by Calvet calorimetry. The dependences P = f(C), ΔHabs.(des.) = f(C) and ΔSabs. = f(C) were obtained (P is the equilibrium pressure of hydrogen, ΔH is the enthalpy of the reaction, ΔS is the entropy of the reaction, C = H/ IMC). It was found that the values of the enthalpy of the reaction of hydrogen with IMC (intermetallic compound) change with changes in the temperature of the process, the concentration of hydrogen in the metal matrix, as well as during the transition from one compound to another. On the plots of the dependence ΔHabs. (des.) = f (C) two sections can be distinguished where the enthalpy values are constant. It is suggested that the observed changes in the thermodynamic parameters of the process are related to the order of filling the interstitial sites 9e and 18g.
The process of filling 9e interstitial sites occurs in two stages with different enthalpy (entropy) of the reactions.
The problem of normal waves in a closed (screened) regular waveguide of arbitrary cross section is considered. It is reduced to a boundary value problem for the longitudinal components of the ...electromagnetic field in Sobolev spaces. The solutions are defined using the variational formulation of the problem. The problem is reduced to the study of an operator function. The properties of the operators involved in the operator function (which are necessary for analyzing its spectral properties) are examined. Theorems are proved concerning the discrete character of the spectrum and the distribution of characteristic numbers of the operator function on the complex plane. The completeness of the system of eigen- and associated vectors of the operator function is investigated. It is proved that the system of eigen- and associated vectors of the operator function is doubly complete with a finite defect.
Background： Talaromyces （Penicillium） marneffei （TIM） is an emerging dimorphic human pathogenic fungus that is endemic to Southeast Asia. TM mostly occurs as an opportunistic infection in patients ...with human immunodeficiency virus （HIV）. The objective of this study was to compare the clinical and laboratory parameters of patients with TM infections who were HIV-positive and HIV-negative and to assess therapies and outcomes. Methods： This was a retrospective analysis of 26 patients diagnosed with disseminated TM infection from September 2005 to April 2014 at Fujian Provincial Hospital, China. Results： Patients with TM infection tend to present with fever, weight loss, and anemia. The time from symptom onset to confirmed diagnosis was greater for HlV-negative patients （n 7; median： 60 days, range： 14-365 days） than for HIV-positive patients （n = 19; median： 30 days, range： 3-90 days, Mann-Whitney U= 31.50, P = 0.041）. HIV-negative patients were more likely to have dyspnea （57.1% vs. 5.3%, Z： = 8.86, P = 0.010）, low neutrophil count （Mann-Whitney U = 27.00, P = 0.029）, high CD4 count （Mann-Whitney U= 0.00, P 0.009）, and high lymphocyte count （Mann-Whitney U = 21.00, P = 0.009）. There were no significant differences in other demographic, clinical, or biochemical characteristics. Among all the patients, 12 HIV-positive patient and 1 HlV-negative patient received amphotericin and fluconazole treatment, 9 of whom improved, l died, 2 had kidney damage, 1 had hypokalemia due to exceeded doses. Conclusions： HIV-negative patients with TM infections tend to have a longer diagnostic interval, a higher percentage of dyspnea, higher levels of CD4 and lymphocytes, and lower neutrophil counts than TM infection in HIV-positive patients. Treatment programs with amphotericin and fluconazole are mostly effective.
The transfer of accelerated electrons in the plasma of flaring loops is accompanied by a hydrodynamic response of the heated plasma. The dynamics of the accelerated electron beam was determined from ...the solution of the one-dimensional, time-dependent relativistic Fokker-Planck equation, and the hydrodynamic response of the thermal plasma was studied by integrating a system of one-dimensional equations using the numerical RADYN code. Thus, the electron distribution function and thermal plasma parameters are changing self-consisting. In this problem the most important values are the energy flux, the duration of continuous injection, and the accelerated electrons spectrum. The most significant for the beam—thermal plasma system is the process of plasma evaporation. The upflows of the plasma (evaporation) increases the looptop plasma density comparing with steady-state value and thus reduces the Coulomb mean free path of fast electrons over time. For impulsive events, we consider heating plasma by electron beams with the energy flux of 3 × 10
10
, 10
11
erg cm
–2
s
–1
in the energy band from 25 keV up to 10 MeV, and duration of 20 s, which is quite consistent with M-X GOES class flares. It is shown that for impulsive events, the effect of plasma “evaporation” for the specified values of the energy flux, isotropic pitch-angle distributions of the accelerated electrons, and power–low energy spectra leads to an increase of the plasma density in the magnetic loop on one-two orders near the transition region only. The effect of plasma evaporation is insignificant and does not affect the hard X-rays from the top of the loop for the considered parameters.
Currently, melatonin (N-acetyl-5-methoxytryptamine) is considered as a multifunctional bioregulator not only in mammals but also in plants. The aim of this work was to study the effect of melatonin ...on the resistance of seedlings of wheat (
Triticum aestivum
L., Dosconala variety) and rye (
Secale cereale
L., Pamyat’ Khudoyerka variety) to high temperature and the functioning of key cellular protection systems (antioxidant and osmoprotective). Rye seedlings were different from wheat seedlings by higher heat resistance, which was manifested in less inhibition of the growth after a 6-h heating at 44°C and less manifestation of the oxidative stress effects. The treatment of wheat seeds with melatonin in concentrations of 20–100 μM significantly decreased the inhibition of the shoot and root growth caused by the effect of a high temperature. The rye seedlings were less affected by melatonin, reducing only the inhibition of the shoot growth. The treatment with melatonin prevented the development of the oxidative stress caused by the effect of high temperature, which was manifested in a decrease in the indices of superoxide radical generation, the content of hydrogen peroxide and malondialdehyde in the shoots of wheat and rye seedlings. The treatment of caryopses of both cereal species with melatonin caused an increase in the catalase activity against the background of the heat stress as well as contributed to the stabilization of peroxidase activity under stress conditions in wheat and caused its increase in rye. In addition, the treatment of caryopses with melatonin caused an increase in the content of soluble carbohydrates under stress conditions but did not affect significantly the content of proline in the shoots of seedlings of both species. In general, a less noticeable effect of melatonin treatment on the functioning of the protective systems in rye was noted. A decrease in the oxidative damage to the cells, an increase in the activity of antioxidant enzymes, and an increase in the accumulation of soluble carbohydrates are the key effects of melatonin under stress conditions.
We point out that realization of quantum communication protocols in programmable quantum computers provides a deep benchmark for capabilities of real quantum hardware. Particularly, it is prospective ...to focus on measurements of entropy-based characteristics of the performance and to explore whether a “quantum regime” is preserved. We perform proof-of-principle implementations of superdense coding and quantum key distribution BB84 using 5- and 16-qubit superconducting quantum processors of IBM Quantum Experience. We focus on the ability of these quantum machines to provide an efficient transfer of information between distant parts of the processors by placing Alice and Bob at different qubits of the devices. We also examine the ability of quantum devices to serve as quantum memory and to store entangled states used in quantum communication. Another issue we address is an error mitigation. Although it is at odds with benchmarking, this problem is nevertheless of importance in a general context of quantum computation with noisy quantum devices. We perform such a mitigation and noticeably improve some results.
Spectrum auctions motivate existing spectrum owners (as sellers) to lease their selected idle channels to new spectrum users (as buyers) who need the spectrum desperately. The most significant ...requirement is how to make the auctions economic-robust (truthful in particular) while enabling spectrum reuse. Furthermore, in practice, both sellers and buyers would require to trade multiple channels at one time, while guaranteeing their individual profitability. Unfortunately, existing designs can not meet all these requirements simultaneously. We address these requirements by proposing True-MCSA, a framework for truthful double multi-channel spectrum auctions. True-MCSA introduces novel virtual buyer group (VBG) splitting and bidding algorithms, and applies a proper winner determination and pricing mechanism to achieve truthfulness and other economic properties, meanwhile successfully dealing with multi-channel requests from both buyers and sellers and improving spectrum utilization. Our experiments show that the auction efficiency is impacted by the economic factors with efficiency degradations within 30%, under different settings. Furthermore, the experimental results indicate that we can improve the auction efficiency by choosing a proper bidding algorithm and using a positive base bid. True-MCSA makes an important contribution on enabling spectrum reuse to improve auction efficiency in multi-channel cases.
Abstract
The present paper is based on the results of long-term studies of planktonic algae and invertebrates in the fresh, soda and saline and technogenically loaded water bodies. The priority ...abiotic factors (hydrochemical composition, hydrophysical parameters), determining the development (species number, dominant species, abundance and biomass) of the main taxonomic groups of phyto- and zooplankton were determined.
Using algebraic-analytic methods, we establish numerous connections, in finite and infinite variants, between amplitudes, coefficients, and source functions of dynamical systems of elasticity theory.
PDF
