Theoretical estimates of the anapole magnetizabilities of C4H4X2 cyclic molecules for X=O, S, Se, and Te

Calculations have been carried out for C4H4X2 cyclic molecules, with X=O, S, Se, and Te, characterized by the presence of magnetic-field induced toroidal electron currents and associated orbital anapole moments. The orbital anapole induced by a static nonuniform magnetic field B, with uniform curl C =∇× B, is rationalized via a second-rank anapole magnetizability tensor aαβ , defined as minus the second derivative of the second-order interaction energy with respect to the components Cα and Bβ. The average anapole magnetizability a equals −χ, the pseudoscalar obtained by spatial averaging of the dipole-quadrupole magnetizability χα,βγ . It has different sign for D and L enantiomeric systems and can therefore be used for chiral discrimination. Therefore, in an isotropic chiral medium, a homogeneous magnetic field induces an electronic anapole Aα, having the same magnitude, but opposite sign, for two enantiomorphs.Fil: Pagola, Gabriel Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Ferraro, Marta Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Provasi, Patricio Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Modelado e Innovación Tecnológica. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Modelado e Innovación Tecnologica; ArgentinaFil: Pelloni, Stefano. Universidad de Modena y Reggio Emilia. Departamento de Química; ItaliaFil: Lazzeretti, Paolo. Universidad de Modena y Reggio Emilia. Departamento de Química; Italia; Itali

Toroidal quadrupole transitions associated to collective rotational-vibrational motions of the nucleus

In the frame of the algebraic Riemann Rotational Model one computes the longitudinal, transverse and toroidal multipoles corresponding to the excitations of low-lying levels in the ground state band of several even-even nuclei by inelastic electron scattering (e,e'). Related to these transitions a new quantity, which accounts for the deviations from the Siegert theorem, is introduced. The intimate connection between the nuclear vorticity and the dynamic toroidal quadrupole moment is underlined. Inelastic differential cross-sections calculated at backscattering angles shows the dominancy of toroidal form-factors over a broad range of momentum transfer.Comment: 11 pages in LaTex, 3 figures available by fax or mail, accepted for publication in J.Phys.

Analysis of experience in application of programs for simulation of road accidents

The growing motorization of society is a necessary condition for economic growth, innovative development and cohesion of the country. Unfortunately, this process also has negative side effects, for example, road traffic accidents due to existing deficiencies in the organization of traffic, driver errors, vehicle breakdowns or problems in road infrastructure that lead to financial costs – of various types. losses and, in the worst case, human casualties. Therefore, reliable, based on scientific conclusions, reconstruction of accidents is needed. Specially developed computer software is the latest technology that allows such a reconstruction to be carried out objectively. It is proposed to consider the experience of various countries, which is primarily aimed at improving the safety of all road users by analyzing and modeling accidents using software products, and then comparing them with each other based on an analysis of advantages and disadvantages. However, it is possible to obtain reliable and reliable calculation results only if the actual numerical values of the corresponding initial calculated data (measurement results, parameters and coefficients) are substituted into the formulas. This circumstance is connected with the validity, objectivity and reliability of the expert's conclusions. Therefore, an urgent task is to increase the reliability of expert studies and reduce the time for their production. The use of special software can significantly increase the efficiency of the work performed to solve the tasks in three aspects: 1) the calculation process is accelerated; 2) in qualitative terms, the use of computer programs reduces the likelihood of arithmetic errors; 3) it is possible to visualize the results of the study

Singular behaviour of the electromagnetic field

The singularities of the electromagnetic field are derived to include all the point-like multipoles representing an electric charge and current distribution. Firstly derived in the static case, the result is generalized to the dynamic one. We establish a simple procedure for passing from the first, to the second case.Comment: Latex, 21.pages, no figure

Parity violation in deuteron photo-disintegration

We analyze the energy dependence for two types of parity-non-conserving (PNC) asymmetries in the reaction $\gamma D\to np$ in the near-threshold region. The first one is the asymmetry in reaction with circularly polarized photon beam and unpolarized deuteron target. The second one corresponds to those with an unpolarized photon beam and polarized target. We find that the two asymmetries have quite different energy dependence, and their shapes are sensitive to the PNC-meson exchange coupling constants. The predictions for the future possible experiments to provide definite constraints for the PNC-coupling constants are discussed.Comment: 22 pages, 12 figures. Submitted to Phys.Rev.C 10Oct.0

Anomalous asymmetry of magnetoresistance in NbSe3_3 single crystals

A pronounced asymmetry of magnetoresistance with respect to the magnetic field direction is observed for NbSe$_3$ crystals placed in a magnetic field perpendicular to their conducting planes. It is shown that the effect persists in a wide temperature range and manifests itself starting from a certain magnetic induction value $B_0$, which at $T=4.2$ K corresponds to the transition to the quantum limit, i.to the state where the Landay level splitting exceeds the temperature.Comment: 4 pages, 6 figures, to be appeared in JETP Let

Radioactive contamination of ZnWO4 crystal scintillators

The radioactive contamination of ZnWO4 crystal scintillators has been measured deep underground at the Gran Sasso National Laboratory (LNGS) of the INFN in Italy with a total exposure 3197 kg x h. Monte Carlo simulation, time-amplitude and pulse-shape analyses of the data have been applied to estimate the radioactive contamination of the ZnWO4 samples. One of the ZnWO4 crystals has also been tested by ultra-low background gamma spectrometry. The radioactive contaminations of the ZnWO4 samples do not exceed 0.002 -- 0.8 mBq/kg (depending on the radionuclide), the total alpha activity is in the range: 0.2 - 2 mBq/kg. Particular radioactivity, beta active 65Zn and alpha active 180W, has been detected. The effect of the re-crystallization on the radiopurity of the ZnWO4 crystal has been studied. The radioactive contamination of samples of the ceramic details of the set-ups used in the crystals growth has been checked by low background gamma spectrometry. A project scheme on further improvement of the radiopurity level of the ZnWO4 crystal scintillators is briefly addressed.Comment: 15 pages, 8 figures, 6 tables, submitted for publicatio

Методика синтеза согласующих устройств для широкополосных радиотехнических устройств с нестабильным импедансом нагрузки на основе метода вещественных частот

The aim of this work is to develop a method for the synthesis of matching devices for broadband radio engineering systems with varying impedance in different operating conditions. To achieve this goal, a criterion (complex criterion) is proposed for minimizing the value of the modulus of the sensitivity invariant of the reflection coefficient function to a change in the load impedance with restrictions on the square of the deviation of the power transmission ratio from a given level. It is proposed to use a combination of methods of real frequencies together with the shown complex criterion, which made it possible to implement an effective approach to the synthesis of matching devices for broadband radio engineering systems with an unstable load impedance. To verify the approach, a matching device was synthesized, which made it possible to reduce the loss of the power transmission factor level transmitted to the UHF/VHF antenna of the AD-44 / CW-TA-30-512 range when it is located in various operating conditions by at least 50 % in relation to losses obtained with a standard matching device.Целью работы является разработка метода синтеза согласующих устройств для широкополосных радиотехнических систем с изменяющимся импедансом в различных условиях их эксплуатации. Для достижения поставленной цели предложен критерий (комплексный критерий) минимизации значения модуля инварианта чувствительности функции коэффициента отражения к изменению импеданса нагрузки с ограничениями на квадрат отклонения коэфициента передачи мощности от заданного уровня. Предложено использовать сочетание методов вещественных частот совместно с показанным комплексным критерием, что позволило реализовать эффективный подход к синтезу согласующих устройств для широкополосных радиотехнических систем с нестабильным импедансом нагрузки. Для верификации подхода было синтезировано согласующее устройство, которое позволило уменьшить потери уровня коэффициента передачи мощности передаваемого в антенну UHF/VHF диапазона AD-44 / CW-TA-30-512 при расположении ее в различных условиях эксплуатации не менее чем на 50 % по отношению к потерям, полученным со штатным согласующим устройством

Towards a microscopic theory of toroidal moments in bulk periodic crystals

We present a theoretical analysis of magnetic toroidal moments in periodic systems, in the limit in which the toroidal moments are caused by a time and space reversal symmetry breaking arrangement of localized magnetic dipole moments. We summarize the basic definitions for finite systems and address the question of how to generalize these definitions to the bulk periodic case. We define the toroidization as the toroidal moment per unit cell volume, and we show that periodic boundary conditions lead to a multivaluedness of the toroidization, which suggests that only differences in toroidization are meaningful observable quantities. Our analysis bears strong analogy to the modern theory of electric polarization in bulk periodic systems, but we also point out some important differences between the two cases. We then discuss the instructive example of a one-dimensional chain of magnetic moments, and we show how to properly calculate changes of the toroidization for this system. Finally, we evaluate and discuss the toroidization (in the local dipole limit) of four important example materials: BaNiF_4, LiCoPO_4, GaFeO_3, and BiFeO_3.Comment: replaced with final (published) version, which includes some changes in the text to improve the clarity of presentatio

SEMI-SYNTHETIC PREPARATION AND STRUCTURE CLARIFICATION OF CURVULIDE A

This research was funded by Russian Science Foundation (project № 20-74-00093)