neutral system
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Atoms ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 101
Author(s):  
Timur A. Isaev ◽  
Shane G. Wilkins ◽  
Michail Athanasakis-Kaklamanakis

Polar radioactive molecules have been suggested to be exceptionally sensitive systems in the search for signatures of symmetry-violating effects in their structure. Radium monofluoride (RaF) possesses an especially attractive electronic structure for such searches, as the diagonality of its Franck-Condon matrix enables the implementation of direct laser cooling for precision experiments. To maximize the sensitivity of experiments with short-lived RaF isotopologues, the molecular beam needs to be cooled to the rovibrational ground state. Due to the high kinetic energies and internal temperature of extracted beams at radioactive ion beam (RIB) facilities, in-flight rovibrational cooling would be restricted by a limited interaction timescale. Instead, cooling techniques implemented on ions trapped within a radiofrequency quadrupole cooler-buncher can be highly efficient due to the much longer interaction times (up to seconds). In this work, the feasibility of rovibrationally cooling trapped RaF+ and RaH+ cations with repeated laser excitation is investigated. Due to the highly diagonal nature between the ionic ground state and states in the neutral system, any reduction of the internal temperature of the molecular ions would largely persist through charge-exchange without requiring the use of cryogenic buffer gas cooling. Quasirelativistic X2C and scalar-relativistic ECP calculations were performed to calculate the transition energies to excited electronic states and to study the nature of chemical bonding for both RaF+ and RaH+. The results indicate that optical manipulation of the rovibrational distribution of trapped RaF+ and RaH+ is unfeasible due to the high electronic transition energies, which lie beyond the capabilities of modern laser technology. However, more detailed calculations of the structure of RaH+ might reveal possible laser-cooling pathways.


2021 ◽  
Vol 922 (1) ◽  
pp. 10
Author(s):  
Kedron Silsbee ◽  
Alexei V. Ivlev ◽  
Munan Gong

Abstract We present a generic mechanism for the thermal damping of compressive waves in the interstellar medium (ISM), occurring due to radiative cooling. We solve for the dispersion relation of magnetosonic waves in a two-fluid (ion-neutral) system in which density- and temperature-dependent heating and cooling mechanisms are present. We use this dispersion relation, in addition to an analytic approximation for the nonlinear turbulent cascade, to model dissipation of weak magnetosonic turbulence. We show that in some ISM conditions, the cutoff wavelength for magnetosonic turbulence becomes tens to hundreds of times larger when the thermal damping is added to the regular ion-neutral damping. We also run numerical simulations, which confirm that this effect has a dramatic impact on cascade of compressive wave modes.


Author(s):  
Georgi M. Mikheev ◽  
Ayrat G. Ziganshin

In this article, we consider the modes of neutrals of 0,38 to 750 kV networks. In any network with different voltage classes, the neutral point of a power transformer winding can operate both in isolated and deaf earthed mode. However, the choice of this mode depends on economic feasibility. The paper presents arguments and advantages of application of system with isolated and compensated neutral of networks with voltage classes 6–35 kV. For networks of these voltage classes various options of connecting arc suppression reactors with step and smooth regulation, as well as low and high impedance resistors in the neutral point of neutralizing transformer or zero sequence filter are considered. On the example of operation of electric networks of the Republic of Chuvashia for many decades it is emphasized that compensation of capacitive currents with arc suppression reactors is an effective and reliable way to protect not only substation electrical equipment from overvoltage, but also to ensure electrical safety of people and animals, as well as reinforced concrete towers from destruction. It is noted that the 6–35 kV networks in the future can be made with deaf earthed neutral. However, this will be possible under the condition that self-supporting insulated wires will be installed on overhead transmission lines instead of bare wires, and cross-linked polyethylene cables will be used on cable lines. It is emphasized that the introduction of work under voltage in 6-35 kV networks and digitalization of substations with the widespread introduction of microprocessor technology will accelerate the transition from a system with insulated (or compensated) neutral to a deaf earthed system. Nevertheless, the decision to switch from the insulated neutral system to a deaf earthed system will remain the prerogative of the design organization based on the specifics of the electrical equipment and the sphere of industrial activity.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Abeer M. Alosaimi ◽  
Hosam A. Saad ◽  
Moamen S. Refat ◽  
Ghaferah H. Al-Hazmi

Abstract Eco-friendly synthesis of ethyl 3-(4-oxo-3-(1-(pyridin-3-yl)ethylideneamino)-2-thioxoimidazolidin-1-yl)propanoate (4) ligand (L) using microwave irradiation technique was described. The structure of thioxoimidazolidine derivative ligand compound has been established based on different types of analyses such as infrared, 1H-NMR, 13C-NMR, and mass spectra as well as elemental analysis. The copper, cobalt, and nickel(II) complexes with molecular formula [M(L)(H2O)4]Cl2 (where M = Co(II), Ni(II), and Cu(II), L = thioxoimidazolidine derivative ligand), have been prepared and well-characterized using microanalytical, conductivity measurements, magnetic, spectroscopic, and physical analyses. Upon the outcome results of analyses, the stoichiometry of the synthesized complexes is 1:1 (M:L). The molar conductance values concluded that the behavior of metal complexes was electrolytes. The 3-(4-oxo-3-(1-(pyridin-3-yl)ethylideneamino)-2-thioxoimidazolidin-1-yl)propanoate chelate acts as a monovalent bidentate fashion via nitrogen and oxygen atoms of both thioxoimidazolidine and propanoate ester moieties. The geometric structures of the synthesized metal complexes are an octahedral configuration based on spectroscopic and magnetic moment studies. The thermogravimetric assignments deduced that the presence of four coordinated water molecules. The synthesized copper(II), cobalt(II), and nickel(II) complexes were biologically checked against G+ and G- bacteria and two species of fungi (Aspergillus Nigaer, and Penicillium Sp.).


Author(s):  
Muhammad Ismail Amayreh Muhammad Ismail Amayreh

The issue of language education is one of the most delicate human issues. It is very relevant to the social and political history of society and is also one of the issues imposed by human reality. It is also one of the issues that has intensified the differences between linguists and psychologists in the ways of acquiring them. Perhaps there are things that stand in front of the acquisition of the second language, language is not a neutral system or a tool to be used in a timely manner or in a generation and that’s it, but is a language with its luster and heritage and attractiveness, what are the factors that stand in front of the acquisition of the second language? Is there a real conflict between languages ​​affecting the acquisition of language in children? What are the most important stages of growth in children and their relation to linguistic development? In fact, there is a difference between mother tongue, second language and foreign language, differentiating between these concepts will make it easier for us to reach the appropriate age to acquire the language. The reason is that the acquisition or learning of any language stems from the goals related to the life of the individual, whether professional, economic or social. The bilingual issue raises an important question: Are the two linguistic systems of the human brain separate or connected?


Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 986
Author(s):  
Marcus Harris ◽  
Martin Zwick

Reconstructability Analysis (RA) and Bayesian Networks (BN) are both probabilistic graphical modeling methodologies used in machine learning and artificial intelligence. There are RA models that are statistically equivalent to BN models and there are also models unique to RA and models unique to BN. The primary goal of this paper is to unify these two methodologies via a lattice of structures that offers an expanded set of models to represent complex systems more accurately or more simply. The conceptualization of this lattice also offers a framework for additional innovations beyond what is presented here. Specifically, this paper integrates RA and BN by developing and visualizing: (1) a BN neutral system lattice of general and specific graphs, (2) a joint RA-BN neutral system lattice of general and specific graphs, (3) an augmented RA directed system lattice of prediction graphs, and (4) a BN directed system lattice of prediction graphs. Additionally, it (5) extends RA notation to encompass BN graphs and (6) offers an algorithm to search the joint RA-BN neutral system lattice to find the best representation of system structure from underlying system variables. All lattices shown in this paper are for four variables, but the theory and methodology presented in this paper are general and apply to any number of variables. These methodological innovations are contributions to machine learning and artificial intelligence and more generally to complex systems analysis. The paper also reviews some relevant prior work of others so that the innovations offered here can be understood in a self-contained way within the context of this paper.


Author(s):  
Samy M. El-Megharbel ◽  
Moamen S. Refat ◽  
Fawziah A. Al-Salmi ◽  
Reham Z. Hamza

Magnesium(II), calcium(II), chromium(III), zinc(II), copper(II), and selenium(IV) sitagliptin (STG) complexes—with the general formulas [Mg(STG)2(Cl)2]·6H2O, [Ca(STG)2(Cl)2], [Cr(STG)2(Cl)2]Cl.6H2O, [Zn(STG)2(Cl)2], [Cu(STG)2(Cl)2]·2H2O, and [Se(STG)2(Cl)2]Cl2, respectively—were designed and synthesized by the chemical reactions between metal(II, III, and IV) chloride salts with an STG ligand in situ methanol solvent in a 1:2 stoichiometric ratio (metal:ligand). Tentative structures of the complexes were proposed based on elemental analysis, molar conductance, magnetic moments, thermogravimetric analysis, and spectral (infrared, electronic, and 1H NMR) data. The particle size and morphological investigation were checked on the bases of scanning electron microscopy, transmission electron microscopy, and X-ray powder diffraction analyses. All the Mg2+, Ca2+, Cr3+, Zn2+, Cu2+, and Se4+ complexes were found to be six-coordinated, wherein the STG ligands act as bidentate chelating agents. This study demonstrates that pancreatic tissues are affected by the induction of experimental diabetes mellitus and clarifies the potential of the synthesized STG complexes, which was found to more significantly improve insulin secretion and the pancreatic and glycometabolic complications of diabetic rats than STG alone.


2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Shengchun Yu ◽  
Yanzhen Pang ◽  
Guici Chen ◽  
Xin Zhou

This paper focuses on the problem of dissipativity analysis for a class of discrete-time neutral stochastic nonlinear systems (DTNSNSs) with time delay and parameter uncertainties. Different from the existing results on this topic of neutral system, a kind of discretizing the neutral system is considered. Firstly, a sufficient condition of the dissipativity, which is dependent on the solution of the Lyapunov–Krasovskii technique and linear matrix inequalities (LMIs), is established. Moreover, the state-feedback controller is designed to guarantee the dissipative performance of the closed-loop system. The effectiveness of the theoretical results is finally demonstrated by a numerical example.


2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Sina Etemad ◽  
Mohammed Said Souid ◽  
Benoumran Telli ◽  
Mohammed K. A. Kaabar ◽  
Shahram Rezapour

AbstractA class of the boundary value problem is investigated in this research work to prove the existence of solutions for the neutral fractional differential inclusions of Katugampola fractional derivative which involves retarded and advanced arguments. New results are obtained in this paper based on the Kuratowski measure of noncompactness for the suggested inclusion neutral system for the first time. On the one hand, this research concerns the set-valued analogue of Mönch fixed point theorem combined with the measure of noncompactness technique in which the right-hand side is convex valued. On the other hand, the nonconvex case is discussed via Covitz and Nadler fixed point theorem. An illustrative example is provided to apply and validate our obtained results.


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