The review describes the general principles of using interfaces based on track membranes with nanoscale channels for the transport of ions from polar solutions to the vapor phase (vacuum). They are ...able to provide the direct input of ions from polar solutions to the vacuum chamber of mass spectrometers of various designs. Various modes of ion extraction from solutions are considered. The application of membrane interfaces to the extraction of ions of bioorganic compounds under atmospheric conditions is demonstrated. A possibility of using such interfaces in tandem devices is also shown.
The importance of development of new methods for reconstruction of an object image given its sinogram and some additional information about the object stems from the possibility of artifact presence ...in the reconstructed image, or its insufficient sharpness when the used additional information does not hold. The problem of recovering artifact-free images of the studied object from tomography data is considered in the framework of the theory of computer-aided measuring systems. Methods for solving it are developed. They are based on narrowing the class of possible images using less artifact-inducing information. An example of such information is the natural condition of non-negativeness of the estimated brightnesses. The main problem that arises is the large dimensionality of the images, which prevents the use of direct algorithms. One proposed method is based on local approach, namely correction of the result of unfiltered backprojection by applying a locally (in the space of the output image) optimal linear transformation. Another method processes a sinogram directly, without using backprojection, using iterative implementation of the measurement reduction technique. Examples of use of the proposed methods for processing teeth sinograms are given.
The paper considers issues related to such a multiple measurements approach where the measurement results affect the number of measurements taken. This may result in a significant increase in the ...measurement time. The work takes into account the change in the probability that the product will be suitable after a specific measurement. These probabilities depend on the number of measurements. The given algorithm for controlling the measurement process shows the random nature of the duration of its execution, which in turn leads to the need to study the duration of multiple measurements. In this paper, a semi-Markov model is constructed that allows us to determine the functions of time distribution between events in the output flow formed after measurements. The resulting model makes it possible to connect it with models of elements of the highest levels of the hierarchy of the production structure. After a specified maximum number of measurements, the model assumes that a part of the measured product is defective and thus shall be rejected. The constructed semi-Markov model may be used to predict the performance of a technical system that uses multiple measurements to improve accuracy.
In the framework of the Einstein–Maxwell-aether-axion theory, we consider a self-consistent model based on the concept of two-level control, which is carried out by the dynamic aether over the ...behavior of an axionically active electrodynamic system. The Lagrangian of this model contains two guiding functions, which depend on four differential invariants of the aether velocity: the scalar of expansion of the aether flow, the square of the acceleration four-vector, the squares of the shear and vorticity tensors. The guiding function of the first type is an element of the effective aetheric metric; this effective metric is involved in the formulation of kinetic terms for the vector, pseudoscalar and electromagnetic fields and predetermines features of their evolution. The guiding function of the second type is associated with the distribution of axions and describes its vacuum average value; basically, this function appears in the potential of the axion field and predetermines the position and depth of its minima. The self-consistent set of coupled master equations of the model is derived. An example of a static spherically symmetric system is considered as an application.
We consider the effect of diffraction due to the finite width of pump radiation illuminating a nonlinear crystal, in which spontaneous parametric down-conversion (SPDC) occurs, on the spatial ...resolution of ghost images. We propose the required formal relations and the computational algorithm and perform numerical simulation with account for the influence of this distorting factor on the quality of ghost images.
The problem of coherent amplification of the out-of-phase mode in tapered multicore fibers with cores arranged in a ring and in a square lattice is studied theoretically. The stability of ...out-of-phase field distributions with respect to both inhomogeneities of the refractive index and the initial wave field distribution is demonstrated in numerical modeling. Coherent combining of radiation into a single beam with good quality and efficiency of about 80% for ring cores arrangement and more than 90% for square cores arrangement is possible. Achievement of 55 MW of total power at the output of a fiber with <inline-formula><tex-math notation="LaTeX">11 \times 11</tex-math></inline-formula> cores is numerically demonstrated.
Functioning of conrod-piston group of internal combustion engine is considered. It is shown that the main method of assembly of this unit is selective assembly, which provides the required accuracy ...of parts joints. The scheme of the assembly set-making is given, a mathematical model of the process of its selective assembly with the selected strategy is built. As a strategy, a single-variant set-making is proposed, in which the assembly is carried out from the groups of the same numbers. The constructed model allows to determine the process indicators, in particular, the probability of obtaining suitable assembled sets, the probability of incomplete elements, forming work in progress and preliminary scrappage. The task of optimal assembly of rod-piston group at specified values of extended tolerances and arrangement of tolerance intervals by rational selection of boundaries of selective groups is set. The solution of this task is given.
Field-induced extraction of ions from a polar solution is implemented with the aid of an interface that represents a polymer track membrane with a conducting coating. A time-of-flight spectrum of ...ions extracted from a KI solution in a water–glycerol mixture is obtained using nanosecond electric-field pulses. Application of the conducting coating allows a significant decrease in the voltage of the extracting pulse and suppression of the effect of secondary processes on the composition of ions generated in a pulsed membrane ion source.
We have applied the measurement reduction technique for the ghost imaging (GI) in fiber optics systems. Ghost images have been reconstructed by numerical simulation of the complete cycle of GI in the ...basic setup of a multimode fiber endoscope beginning from the propagation of randomly modulated light through a multimode fiber and ending by GI calculation using numerical methods of single-pixel visualization. We have used prior information on the investigated object to obtain high-quality reconstructed ghost images. It is shown that for the number of used patterns of illumination of the object that is much smaller than the number of pixels of the image being reconstructed, the object reconstruction error can be reduced despite the limitation imposed on the number of modes propagating through the optical fiber and forming incoherent radiation. For comparison, we have used several versions of the compressed sensing method and the traditional correlation method. It is demonstrated that the proposed version of the measurement reduction technique applied to multimode fibers shows comparable and often even better results than the traditional correlation method and the compressed sensing method.
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