Volume 73, Number 3, 2021
 
THEORETICAL, MATHEMATICAL, AND COMPUTATIONAL PHYSICS
 
Super rogue wave states in the classical massive Thirring model system
YANLIN YE, LILI BU, CHANGCHANG PAN, SHIHUA CHEN, DUMITRU MIHALACHE, FABIO BARONIO
Rom. Rep. Phys. 73, 117 (2021)
Abstract. We obtain the exact explicit super rogue wave solutions of the classical massive Thirring model system, using a nonrecursive Darboux transformation method along with some algebraic manipulations. We reveal that in such a vector system, both rogue wave components, whenever they take the fundamental Peregrine soliton structure or the super rogue wave ones, may possess the same maximum peak-amplitude factor, behaving like those occurring in scalar nonlinear systems. However, due to the coherent coupling, the two super rogue wave components may exhibit drastically different spatiotemporal distributions, despite that they evolve from almost the same background fields. The modulation instability responsible for the rogue wave excitation in such a coupled system is also discussed.
Article no. 117: PDF 
New mathematical model governing the propagation of two-wave modes moving in the same direction: classical and fractional potential KdV equation
IMAD JARADAT, MARWAN ALQURAN, MOHAMMED ALI, TUKUR A. SULAIMAN, ABDULLAHI YUSUF, QUTAIBEH KATATBEH
Rom. Rep. Phys. 73, 118 (2021)
Abstract. In this study, we devote our effort in investigating the behavior of a new two-mode potential Korteweg-de Vries (KdV) equation. This model describes the motion of two waves propagating in the same direction simultaneously. The interaction of the so-called two-wave modes depends on the increasing of embedded phase velocity. Three robust schemes are utilized to find explicit solutions to this new model. Moreover, the time-space fractional version of the two-mode potential KdV equation is investigated. Finally, a graphical analysis is provided to study some physical aspects of these traveling waves.
Article no. 118: PDF 
The quantum affinity of qubits subjected to noisy quantum channels
IULIA GHIU
Rom. Rep. Phys. 73, 119 (2021)
Abstract. There are many measures in quantum information theory that quantify the distinguishability between two quantum states. In this paper, we use a recently introduced concept called quantum affinity for analyzing the modification of the quantum state of a qubit subjected to the influence of three quantum noisy channels: the bit flip channel, the depolarzing channel, and the amplitude damping channel. Further, we make a comparison between the quantum affinity and the square root of the fidelity and discuss the results for all the above-mentioned quantum channels.
Article no. 119: PDF 
New extended (3+1)-dimensional KDV6 equation and other equations derived from the same hierarchy: Painleve integrability
NOUFE H. ALJAHDALY, ABDUL-MAJID WAZWAZ, S.A. EL-TANTAWY, H.A. ASHI
Rom. Rep. Phys. 73, 120 (2021)
Abstract. This work investigates the integrability of an extended (3+1)-dimensional hierarchy of nonlinear evolution equations (NLEEs), which include the sixth-order Korteweg-de Vries (KdV6) equation. These NLEEs describe several nonlinear phenomena in fluid dynamics and in other physical settings. The integrability of these equations is demonstrated via applying the Painleve analysis. We show that these equations are characterized by distinct dispersion relations. By applying Hirota's direct method, several soliton solutions for each equation are obtained and for the general case too.
Article no. 120: PDF 
Approximate solution of coupled two-dimensional Burgers' equation by a variant of decomposition method
ION AUREL CRISTESCU
Rom. Rep. Phys. 73, 121 (2021)
Abstract. In this paper we are concerning with the computation of the numerical solution of coupled two-dimensional Burgers' equation. The method we developed combines a variant of decomposition technique and the finite-differences method. The performance of our algorithm was successfully tested.
Article no. 121: PDF 
Line states in Kagome lattice
XIANGLIAN LIU, XIN GUO, JINGCAI YANG, PU LI, JIANGUO ZHANG, YI LIU
Rom. Rep. Phys. 73, 122 (2021)
Abstract. The line states in the Kagome lattice (KL) are studied both theoretically and numerically. Straight as well as zigzag line states in the different-boundary KLs are obtained by using the tight-binding approach, which cannot be interpreted as a linear superposition of the traditional flatband compact localized states (CLSs). According to Bloch eigenstates of two types of line states, the strong localization capability can be obtained by adjusting the position and phase of input beams properly. In order to further prove the existence of line states, the continuous model based on the Schrödinger equation is used by the split-step fast Fourier method. The results indicate that the ideal line states exist in the KL. The transmission characteristics of line states in the KL can be applied to the complex image display technologies.
Article no. 122: PDF 
Bright-dark solitons of the two-component nonlocal nonlinear Schrödinger equations coupled to Boussinesq equation
YUNKAI LIU, JIGUANG RAO
Rom. Rep. Phys. 73, 123 (2021)
Abstract. Motivated by the potential applications of multi-component nonlocal nonlinear Schrödinger (NLS) and NLS-type equations in nonlinear optics, the twocomponent nonlocal NLS equation coupled to the Boussinesq (2CNNLS-Boussinesq) equation is proposed and investigated. By employing the Kadomtsev-Petviashvili hierarchy reduction method, the multiple bright-dark soliton solutions, namely, one component featuring solitons with nonzero boundary condition and the other two components featuring solitons with zero boundary condition, are constructed in determinant forms. Based on the asymptotic analysis for the two-solitons, we bring out that the dark two-solitons possess three non-degenerate types and two degenerate types, while the bright two-solitons only admit one non-degenerate type. Additionally, we also consider the resonant-type collision of the bright-dark two-solitons, which is resulted by the phase shifts tending to zero in the collision process. The resonant-type collision can generate periodic waves in the region where the two solitons intersect. For the bright-dark four-solitons, we consider the bound state two-solitons pairs and the corresponding resonant-type collision between the two-solitons pairs. Finally, we also propose the arbitrary N component nonlocal NLS-Boussinesq equation and some other nonlocal versions of the 2CNNLS-Boussinesq equations.
Article no. 123: PDF 
 
OPTICS AND PHOTONICS, PLASMAS, LASER AND BEAM PHYSICS
 
On the performance of plasmonic-based optical fiber magnetic field sensor: comparison between analytical and finite element methods
V. A. POPESCU, A. K. SHARMA
Rom. Rep. Phys. 73, 406 (2021)
Abstract. An analytical method based on Bessel functions is applied to the calculation of transmission loss, average sensitivity, and magnetic field resolution for the TM01 and first order of two-fold degenerate plasmon modes in an optical fiber structure with three layers. In this method, the electromagnetic field is represented by a Bessel function of the first kind in the core layer (silicon), a linear combination of the Hankel functions in the gold layer, and a modified Bessel function of the second kind in the magnetic fluid layer. The values of the effective indices calculated by using the finite element method (FEM) are in agreement with our analytical method. The resolution RH = 0.75 Oe for the magnetic field detection in an optical fiber structure calculated with the analytical method for the first-order plasmon mode is better than the value RH = 32.05 Oe for the TM01 mode when the volume fraction c of Fe3O4 particles in a magnetic fluid solution is 1.48%. Also, the resolution RH = 0.019 Oe for the magnetic field detection in a truncated honeycomb structure calculated with FEM for a TM01 mode is finer than the value (0.080 Oe) for the first-order plasmon mode and the one (0.241 Oe) for a fundamental HE11 mode, when c = 1.48%. In addition, it is very important to note that the resolution RH = 0.0028 Oe for the magnetic field detection in a truncated honeycomb structure calculated with FEM for the first-order plasmon mode is very close to a recently reported value where RH = 0.0023 Oe for a HE11 mode when c = 1.93%.
Article no. 406: PDF 
New types of surface waves in a crystal with an abrupt change in Kerr nonlinearity in dependence on the field amplitude and a fully shielding coating
S.E. SAVOTCHENKO
Rom. Rep. Phys. 73, 407 (2021)
Abstract. In this paper, we describe new types of transverse electric surface waves in a semi-infinite crystal covered with a fully shielding film and with an abrupt change in Kerr nonlinearity. We consider five various types of boundary regimes differing from each other in the set of boundary conditions. It is shown that the position of the boundary of the near-surface domain corresponding to the region of sharp change in the gradient of the refractive index could be controlled by the wave frequency, the switching field, and the optical characteristics of the crystal.
Article no. 407: PDF 
 
CONDENSED AND SOFT MATTER PHYSICS
 
The deformation-diffusion mechanism of the formation of n-n+-transitions in semiconductors under the influence of pulsed laser irradiation
R. PELESHCHAK, O. KUZYK, O. DAN'KIV
Rom. Rep. Phys. 73, 506 (2021)
Abstract. The deformation-diffusion theory of the formation of n-n+-transitions in n-type semiconductors under the influence of pulsed laser irradiation is developed. This theory takes into account the diffusion of defects in nonuniformly deformed field (created both by the presence of defects itself and by a gradient of temperature) and non-local interaction between defects and atoms of the matrix. The regularities of the formation of barrier structures in the near-surface layer of irradiated germanium have been investigated depending on the degree of doping, the duration of the laser pulse, the substrate temperature, and the intensity of the laser irradiation. It is shown that depending on the duration of the laser pulse and the intensity of the laser irradiation, the electrons are localized near the surface of the semiconductor or their localization area shifts to the depth of the crystal. The conducted theoretical calculations are in good agreement with the experimental data of other scientific works.
Article no. 506: PDF 
 
ENVIRONMENTAL AND EARTH PHYSICS
 
Influence of meteorological variables on people with cardiovascular diseases in Bucharest, Romania (2011-2012)
M.-M. MICHEU, M.-V. BIRSAN, I.-A. NITA, M. D. ANDREI, D. NEBUNU, C. ACATRINEI, L. SFICA, R. SZEP, A. KERESZTESI, P.F. DE ARROYABE HERNAEZ, S. ONCIUL, A. SCAFA-UDRISTE, M. DOROBANTU
Rom. Rep. Phys. 73, 707 (2021)
Abstract. The study investigates the influence of weather on people with acute cardiovascular syndromes (ACS) in Bucharest, Romania, using daily records from October 2011 until December 2012. The highest number of cases with ACS occurred in February 2012, which was an abnormally cold month. Data aggregated at weekly scale show no significant correlations between the total number of ACS and the meteorological variables. However, after classifying the medical data into subgroups, we found statistically significant positive correlations (p < 0.05) between the number of female patients diagnosed with unstable angina and the Temperature-Humidity Index, as well as with air temperature.
Article no. 707: PDF 
The analysis of the seismic sequence started on November 22, 2014 based on ETAS model
C. GHITA, M. DIACONESCU, R. RAICU, I. A. MOLDOVAN, G. ROSU
Rom. Rep. Phys. 73, 708 (2021)
Abstract. The purpose of this study consists in the analyses of ETAS (Epidemic-Type Aftershock Sequence) parameters for the sequence recorded on November 22nd, 2014 in Marasesti area. The main shock of the sequence, a moderatesize earthquake with ML = 5.7, at 40.9 km depth, is the largest crustal event instrumentally recorded at the bending of the Eastern Carpathians. The ETAS model parameters for the Marasesti area were estimated using the seismic events from the Romplus catalogue, between January 1, 2010 (00:00:00) and November 17, 2017 (00:00:00), with magnitude between 1.2 < Mw < 5.4 and depth 0.6 < h < 70 km. The estimated model is applied further on an independent data set recorded in the same area, for automatic identification of Marasesti sequences using the residual analysis techniques. The studied model encourages research for evaluation of the real-time probability earthquake occurrence and sustains the international initiatives such as the Operational Earthquake Forecast (OEF).
Article no. 708: PDF 
Evaluation of the predominant frequency of sedimentary layers resonance using Vrancea crustal event of November 22, 2014
E.F. MANEA, A. COMAN, C. O. CIOFLAN
Rom. Rep. Phys. 73, 709 (2021)
Abstract. In this study, the predominant frequency of resonance was identified, interpreted and mapped along the National Seismic Networks of Romania, Republic of Bulgaria and Republic of Moldova, for the November 22, 2014, ML = 5.7 crustal event generated at 40 km depth in the Vrancea seismogenic area. The horizontal-tovertical spectral ratio technique was applied on the three-component single station measurements to investigate the local variability at each site. The observed predominant peaks are matching the fundamental frequency of resonance at some sites located on a superficial sedimentary cover and reach higher frequencies for the ones on deep sedimentary basins.
Article no. 709: PDF 
Main active faults from Romania. Part III: fault systems from Dacia tectonic unit
M. DIACONESCU, C. GHITA, I.A. MOLDOVAN, E. OROS, E.G. CONSTANTINESCU, M. MARIUS
Rom. Rep. Phys. 73, 710 (2021)
Abstract. The main target of this paper is to established a correlation between the seismicity of the Western part of Southern Carpathians (Romania) and the active tectonic (faults systems) of the area, the second target is to create a specific database of the faults (ROmanian DAtabase of SEismogenic Faults-RODASEF) in SHARE manner, for seismic hazard assessment process. In the studied area, we highlit the main faults form Hateg Basin, Moldova Noua-Oravita Basin, Caransebes-Orsova basin (Teregova) and Orsova-Mehadia-Cornereva faults system, which generate seismic sequences such as: 2002 Moldova Noua, 1991 Mehadia-Baile Herculane, 2014 Teregova, 2011 and 2013 Hateg seismic sequences.
Article no. 710: PDF 
 
APPLIED AND INTERDISCIPLINARY PHYSICS
 
Efficient and versatile laboratory electrodialysis device used for removal of iron ions from a synthetic wastewater
S. CAPRARESCU, V. PURCAR, V. RADITOIU, C. A. NICOLAE, C. MODROGAN, A. A. SCARLAT
Rom. Rep. Phys. 73, 802 (2021)
Abstract. The present paper reports an efficient and versatile laboratory electrodialysis device used for removal of iron ions from a synthetic wastewater with novel polymer membrane based on chitosan (CS)-silver nitrate (Ag) solution. Our laboratory electrodialysis device was operated under potentiostatic operation mode to maintain the constant voltage of 7.5 V, for 90 minutes. The results showed that the rejection of Fe2+ was higher (> 65%) for the polymer membrane with CS-Ag solution. The physical, chemical and mechanical properties of the obtained polymer membranes were investigated by Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DSC) and Optical Microscopy. FTIR spectra showed that some peaks were shifted to higher wave numbers possible due to the incorporation of CS-Ag solution in the polymer matrix. A peak that is shifting from 1435 cm-1 (polymer membrane with CS-Ag solution) to 1428 cm-1 (polymer membrane without CS-Ag solution) was attributed to vibrations of hydroxyl (-OH) functional groups from polyethylene glycol and chitosan. TGA-DSC results indicated an excellent thermal stability up to 355℃ and maximum decomposition temperature over 500℃ for the obtained polymer membranes. The optical microscope image confirmed that the chitosan and polyethylene glycol chains help in stabilization of the silver particles.
Article no. 802: PDF 
A brief study on the chemistry of some Roman glass finds from Apulum
R. BUGOI, O. MURESAN
Rom. Rep. Phys. 73, 803 (2021)
Abstract. This paper is a concise study reporting the chemical analyses on several Roman glass fragments (2nd-3rd c. AD) discovered at Apulum (nowadays Alba Iulia, Romania). The composition of the archaeological finds was determined using a combination of Ion Beam Analysis (IBA) methods, namely PIXE (Particle Induced X-ray Emission) and PIGE (Particle Induced Gamma ray Emission) performed in external beam mode at the AGLAE accelerator, Louvre Palace (Paris, France). The analyzed glass fragments have compositions typical for the Early Roman period. Most of them bear clear signs of recycling, suggesting their manufacturing in secondary workshops possibly local ones, by using various types of cullet.
Article no. 803: PDF 
 
PHYSICS EDUCATION
 
Building and testing a wind turbine experimental kit for students
B. CHIRIACESCU, FABIOLA SANDA CHIRIACESCU, SANDA VOINEA
Rom. Rep. Phys. 73, 905 (2021)
Abstract. This study shows the possibility to create an experimental kit for students', in order to understand how wind turbines work and why the knowledge of aerodynamics is important. The experimental kit contains three 3D printed wind turbines with a vertical ax and different form of blades: straight, inclined and curved. Several measurements were performed, in order to establish the most efficient turbine. The experimental results were compared with the simulated ones and both studies had determined a better behavior in the wind for the turbine with curved blades. Building and experimenting the simple models of turbines can be integrated in a Science, Technology, Engineering and Mathematics (STEM) based learning project for upper secondary students. The design of the wind turbines, their simulation in a virtual wind tunnel and their testing in a real wind tunnel can be integrated into a science, technology, engineering and math (STEM) learning project for students.
Article no. 905: PDF 

This is an electronic version of Volume 73 Number 3 2021
 
   
 
Copyright © 2003-2013 Editura Academiei Romane   ISSN 1221-1451 43 822   © Manu Catalin, INCDFM/INFLPR  
Online: http://www.infim.ro/rrp   © 2006 -        On-line ISSN 1841-8759