In the study, the characteristics of the phase transition from a face-centered cubic crystal to a homogeneous phase in helium were calculated based on the correlation cell–cluster extension. A ...comparison of theoretical data with experimental data was conducted, and good agreement was obtained. The use of data on phase transitions in helium for estimating the thermodynamic characteristics of the phase transition in a quantum system of hard spheres is discussed.
In the present work, for the first time, a generalized Guggenheim equation for a system of hard spheres has been obtained based on the use of Euler’s accelerated convergence method. This equation ...allows for the consideration of an arbitrary number of known virial coefficients. For the metastable region, this equation is generalized to account for the asymptotic behaviour of free energy at high densities. The obtained expression for the compressibility of the homogeneous phase of a hard sphere system describes the data of the numerical experiment within the limits of its accuracy.
Shape recovery in conventional shape memory alloys is typically a relatively slow process showing low heating rate sensitivity. In contrast to that, some shape memory alloys such as Ni–Fe–Ga–Co, ...Cu–Al–Ni, Cu–Al–Fe–Mn can exhibit the effect of burst-like shape recovery when the original shape is restored almost instantaneously in a very narrow temperature range. Here we report on an abnormal stress-strain behavior of Ni49Fe18Ga27Co6 single crystals upon uniaxial compression along the 110 axis and caloric effects during burst-like recovery of shape memory strain in the samples. Differential scanning calorimetry (DSC) study revealed that DSC peak shifts to lower temperatures with increasing heating rate.
•Ni49Fe18Ga27Co6 single crystals exhibit an anomalous stress-strain behavior when compressed along the 110 axis.•Ni49Fe18Ga27Co6 single crystals compressed along the 110 axis manifest a burst-like shape recovery.•The burst-like shape recovery is accompanied with an anomalous heat intake.•The transition temperature of the burst-like shape recovery is decreasing with increasing heating rate.
In this work, the free energy and the equation of state of a system of solid spheres in narrow cylindrical pores are determined using the combined method of accelerated convergence of series. This ...method includes the Euler method and a method based on taking the behavior of the system into account at high densities near the dense packing and on the idea of the effective number of the nearest neighbors. The results are compared with the data of a computer experiment for three different values of pore size and in all cases good agreement between theory and experiment was obtained. These are much better than the results of virial expansion, and when the transverse pore sizes increase, better than the results found on the basis of a series in powers of pressure as well. The method makes it possible to estimate the limits of applicability of the method of convergence acceleration, based on the transition from a series in density to a series in terms of pressure. To do this, the density with close packing and the maximum allowable density found by the method of Euler are compared. If these densities are close, then only the Euler method can be used. In the case of a significant difference, a combined method of accelerated convergence is required.
Record thick (up to 100 μm) epitaxial layers of a prospective metastable semiconductor Ga
2
O
3
were grown by HVPE (Halide Vapor Phase Epitaxy) on GaN buffer layers on
c
-sapphire substrates. The ...X-ray diffraction pattern of the layers show that the structure of the layer is a pure κ(ε)-Ga
2
O
3
without any other phases. At the same time, the organization of a domain structure was observed, which manifests itself in the form of pseudohexagonal prisms that retain the orientation of the gallium nitride sublayer. Schottky diodes with nickel contacts were fabricated and the electrical and photoelectric properties of the layers were studied. Capacitance–voltage (
C
–
V
) and frequency–capacitance (
C
–
f
) dependencies were studied, photocurrent and photocapacitance spectra were measured.
Research on ribonucleic acid (RNA) structures and functions benefits from easy-to-use tools for computational prediction and analyses of RNA three-dimensional (3D) structure. The SimRNAweb server ...version 2.0 offers an enhanced, user-friendly platform for RNA 3D structure prediction and analysis of RNA folding trajectories based on the SimRNA method. SimRNA employs a coarse-grained model, Monte Carlo sampling and statistical potentials to explore RNA conformational space, optionally guided by spatial restraints. Recognized for its accuracy in RNA 3D structure prediction in RNA-Puzzles and CASP competitions, SimRNA is particularly useful for incorporating restraints based on experimental data. The new server version introduces performance optimizations and extends user control over simulations and the processing of results. It allows the application of various hard and soft restraints, accommodating alternative structures involving canonical and noncanonical base pairs and unpaired residues, while also integrating data from chemical probing methods. Enhanced features include an improved analysis of folding trajectories, offering advanced clustering options and multiple analyses of the generated trajectories. These updates provide comprehensive tools for detailed RNA structure analysis. SimRNAweb v2.0 significantly broadens the scope of RNA modeling, emphasizing flexibility and user-defined parameter control. The web server is available at https://genesilico.pl/SimRNAweb.
We have obtained equations for calculating the parameters of phase transitions in particle systems with a nonnegatively defined interaction potential. The parametrized Gibbs distribution is part of ...the basis of our derivation. It takes the features of a non-negatively defined interaction potential into account and leads to the corresponding Bogolyubov chain of equations. Using this approach, we obtain a convenient method for finding the free energy of the system. On the basis of this method, we have studied the phase transition in a system of hard spheres and the dependence of the phase-transition temperature on the temperature of argon at high pressures.
This article presents an effective method for detecting surface defects via magnetic field anomalies occurring over cracks, cleavages, and crevices of angular elements of complex-profile parts made ...of ferromagnetic materials. The method is based on the spectral analysis of the signal of a tangentially oriented vibration–induction transducer (VIT). The amplitude–phase method of analysis and research based on mathematical modeling of the signal of the VIT in the form of a trigonometric series is theoretically substantiated. The results of recording and analyzing the distribution of the magnetic field strength and the amplitude–phase spectrum of the signal of the VIT along a surface with involute and threaded profiles are presented. The results were obtained on control samples of a gear wheel, a threaded rod, and a bolt with artificial defects. The conditions for detecting surface defects based on the results of measuring the amplitude and phase of the first two harmonics of the signal of the VIT are formulated. The parameters of the control scheme of the involute and threaded profiles with module and pitch values of the order of several millimeters, which make the automation of the control process with a satisfactory signal-to-background ratio possible, are determined. The method is designed to control the continuity of parts containing profiled surface areas (i.e., fillet, involute, threaded, and splined profiles).
The paper describes the measuring aids (magnetometers and light sensors) and attitude determination algorithms of SamSat-ION nanosatellite. The Kalman filter based on magnetometer measurements only ...is used as a basic algorithm, and the auxiliary QUEST algorithm provides a priori estimation of the quaternion input to the Kalman filter. The two-step algorithm simulation has been performed, and its efficiency has been verified.
The purpose of this research was to assess the influence of photosynthetic activity of a new promising oat variety, Irtysh 33, on the yield formation and quality of green mass. Experiments were ...carried out in 2017–2022 in Western Siberia. The soil is leached common chernozem. The moisture level was optimal in 2019 (HTI = 1.10), excessive in 2018 (HTI = 1.39), and low in 2017 and 2020–2022 (HTI = 0.58–0.77). The object of the research is the new promising variety Irtysh 33 (the standard is the Orion variety). On average, Irtysh 33 was characterized by a more developed leaf apparatus over the study period, with an assimilation surface area being 35.5% higher in the heading phase and 24.9% higher in the flowering phase than that of the standard. The mass fraction of dry biomass of the new variety was greater than that of the standard variety in these periods (by 14.6 and 10.2%, respectively); the yield of the fodder mass was 7.3 and 3.2 t/ha higher, respectively. Such results are determined, among other things, by an increase in the photosynthetic potential of the Irtysh 33 variety by 30% compared to the standard variety. In the heading phase, the protein content in the fodder mass was 0.4% higher, the protein yield was 1.07 t/ha higher, and the mass fraction of fiber was 0.7% lower in the new variety than in the standard variety. The influence of the accumulation of dry biomass on the formation of the mass fraction of fiber increased from heading to flowering from
r
= 0.515 ± 0.02 to
r
= 0.684 ± 0.103, its effect on the yield increased from
r
= 0.479 ± 0.008 to
r
= 0.602 ± 0.015; the effect of net photosynthetic productivity on the accumulation of dry biomass increased from
r
= 0.115 ± 0.004 to
r
= 0.419 ± 0.017, and its effect on the yield increased from
r
= 0.460 ± 0.020 to
r
= 0.601 ± 0.051. The medium direct correlation of the assimilation leaf surface with the mass fraction of protein, recorded in the heading phase (
r
= 0.640 ± 0.19), changed for the medium inverse correlation in the next phase (
r
= –0.508 ± 0.021).
