The Fe–0.44%C–1.8%Si–1.3%Mn–0.82%Cr–0.28%Mo steel treated by the quenching–partitioning process showed a product of strength and elongation of 30 GPa % with yield stress of 1350 MPa. Such a combination of high ultimate tensile strength and good ductility is attributed to a high portion of retained austenite (≥20%) transforming to martensite under tension. The high yield stress is provided by carbon supersaturation of austenite and a high dislocation density in this phase.
Several statements of the problems of synthesis of a holographic mask in the form of optimization problems for quality of holographic images are presented. An effective algorithm for the synthesis of holographic masks based on FFT with the complexity O(NlnN), where N is the number of elements of the depicted object, is described. Based on this algorithm, a scalable software package has been developed and implemented that allows synthesizing holographic masks for various lithography applications, including the production of MEMS, MOEMS, and high-end chips. Experimental results are presented.
The worst disturbance problem for an oscillator with quadratic-law damping is stated. The role of the disturbance is played by an external force applied to the oscillator. It is assumed that this force acts in one direction, that the integral of this force with respect to time is given, and that at the initial instant of time the oscillator is resting in the equilibrium position. It is required to find a time history of the disturbing force that maximizes the maximum (with respect to time) of the absolute value of the displacement of the oscillator’s body from the equilibrium position. The worst disturbance from among rectangular pulses under which the disturbing force is constant on the initial time interval and is equal to zero outside of this interval is found and investigated.
An approach to creating compact and miniature infra- and low-frequency vibration isolation systems based on layered composite elastic elements with adjustable negative and quasi-zero stiffness is presented. New problems of modeling the given parameters of the stiffness and bearing capacity of elements of certain geometry under combined loading have been solved by varying the structure, elastic properties, and arrangement of layers and controlling the local mobility of the binder. The correctness of the approach is based on the results of experimental design and research of system models. This approach can qualitatively change the solution of a number of critical problems in vibroacoustics of aviation and other advanced engineering.
The results of study of the behavior of surface plasmon polaritons in the layered structure of a VO2‒SiO2-graphene-based hyperbolic metasurface under the influence of an external magnetic field before and at the beginning of the phase transition of vanadium dioxide are presented. As a result of calculations, it is shown how the isofrequency contour of surface plasmons changes taking into account the different direction of the external magnetic field. It is also shown how an external magnetic field affects the direction of static magnetization caused by the inverse Faraday effect. This work can offer additional ways to control the behavior of surface plasmons, as well as become the basis for the study of new self-adjusting structures.
Based on the energy approach to the process of brittle fracture, a new energy criterion for fracture was obtained in the case when an arbitrary normal symmetrical load acts on the surface of an isolated crack.
Based on analysis of the specific features inherent in the trajectory of a charged particle moving in an inhomogeneous electromagnetic wave, the physical processes determining the nature of ponderomotive forces are specified. In particular, the reason for switching the accelerated motion of a particle passing through an electrical field with zero amplitude in the direction perpendicular to the electrical field to deceleration with an increase in the electrical field amplitude is detailed. The effect of the inertial mass on the trajectory of a charged particle moving in an inhomogeneous electromagnetic wave is determined.
The prospects for reducing the carbon intensity of the Russian economy and the possibility of achieving climate neutrality of the national economy by 2060 are studied. On the basis of a historical-extrapolation approach to the study of the development of various sociotechnical systems by comparison with the dynamics of carbon indicators of the economies of the leading countries of the world, it is shown that full compensation for anthropogenic emissions of greenhouse gases (GHGs) by absorption by the biosphere (primarily forests) is theoretically possible with implementation of difficult-to-implement large-scale reform programs in all sectors of the country’s economy—from energy to forestry. Thus, in an optimistic scenario, the rate of decline in specific GHG emissions per capita should be the maximum value achieved in the world over the past 50 years at 1% per year, and forest management should include full compensation for growing deforestation and a 50% reduction in forest losses from fires, which are currently the second (after energy) source of GHG emissions into the atmosphere. The most likely scenario is one with a rate of reduction in specific GHG emissions per capita of 0.5%/year, and a significant reduction in the sinking capacity of forests to the level of 1990 due to the aging of forests and imperfect reforestation activities. Under the latter scenario, net GHG emissions by 2060 could reach 0.7 Gt CO2eq, which would require the creation of a national industry for large-scale carbon capture and storage in order to achieve climate neutrality of the Russian economy.
Magnetic particles based on superparamagnetic iron oxide nanocrystals find increasing application in the development of modern techniques for high-precision express determination of biomolecule concentrations. In this work, based on an original technique for the ultrasensitive detection of nonlinear magnetic nanomaterials, we develop a universal method for the use of magnetic particles as polyfunctional agents that simultaneously perform several different functions in a single assay for topical tasks of biochemical and medical diagnostics. The method is tested for the rapid quantitative detection of cardiac markers and SARS-CoV-2-associated molecular markers in complex matrices. The proposed method is promising for creating test systems for prehospital monitoring, in particular, emergency molecular diagnostics in patients with a suspected acute myocardial infarction, and the rapid detection of the coronavirus infection.
The dynamic problem of thermoelasticity with a localized inclusion in a medium is considered. It is shown that in the resonant regime an important role is played by the coupling coefficient of the temperature and strain fields. The coupling of the problem and the presence of a discrete spectrum lead to the appearance of an additional term in the expression for temperature, which is localized and does not describe the diffusion process.
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