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interplay of parallel electric field and trapped electrons in kappa-maxwellian auroral plasma for emEC instability

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Communications in Theoretical Physics 2021年第1期73卷 78-86页

作者： m nazeer m n S Qureshi C Shen Department of Physics GC UniversityLahore(54000)Pakistan Shenzhen Graduate School HIT CampusUniversity Town of ShenzhenShenzhen 518055China

in this paper,propagation characteristics of electromagnetic electron cyclotron(emEC)waves based on kappa-maxwellian distribution have been investigated to invoke the interplay of the electric field parallel to the Earth’s magnetic field and auroral trapped *** dispersion relation for emEC waves in kappa-maxwellian distributed plasma has been derived using the contribution of the parallel electric field and trapped electron *** results show that the presence of the electric field has a stimulating effect on growth rate,which is more pronounced at low values of wave *** is also observed that as the threshold value of trapped electron speed is surpassed,it dominates the effect of the parallel electric field and emEC instability is enhanced *** electric field acts as another source of free energy,and growth can be obtained even in the absence of trapped electron drift speed and for very small values of temperature *** the present study reveals the interplay of the parallel electric field and trapped electron speed on the excitation of emEC waves in the auroral region.

关键词： emEC waves kappa-maxwellian distribution trapped electrons parallel electric field in aurora

Conversion of an atomic to a molecular argon ion and low pressure argon relaxation

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Chinese Physics B 2016年第1期25卷 697-705页

作者： m n Stankov A P Jovanovie V Lj markovic S n Stamenkovic Department of Physics Faculty of Sciences and MathematicsUniversity of Ni Viegradska 33Ni 18001Serbia

The dominant process in relaxation of DC glow discharge between two plane parallel electrodes in argon at pressure 200 Pa is analyzed by measuring the breakdown time delay and by analytical and numerical models. By using the approx- imate analytical model it is found that the relaxation in a range from 20 to 60 ms in afterglow is dominated by Ar＋ ions, produced by atomic-to-molecular conversion of Ar＋ ions in the first several milliseconds after the cessation of the discharge. This conversion is confirmed by the presence of double-Gaussian distribution for the formative time delay, as well as con- version maxima in a set of memory curves measured in different conditions. Finally, the numerical one-dimensional （1D） model for determining the number densities of dominant particles in stationary DC glow discharge and two-dimensional （2D） model for the relaxation are used to confirm the previous assumptions and to determine the corresponding collision and transport coefficients of dominant species and processes.

关键词： argon discharge afterglow relaxation fluid model plasma reactions

Effect of nb addition on the microstructural,mechanical and electrochemical characteristics of AlCrFeniCu high-entropy alloy

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international Journal of minerals,metallurgy and materials 2020年第10期27卷 1332-1340页

作者： n.malatji A.P.i.Popoola T.Lengopeng S.Pityana Tshwane University of Technology PretoriaSouth Africa Council for Scientific and industrial Research PretoriaSouth Africa

AlCrFeniCunbx(x=0.05,0.15,and 0.26)high-entropy alloys(HEAs)were successfully fabricated using the laser metal deposition *** laser power of 1600 W and scanning speed of 1.2 m/min were used during laser processing of the *** microstructural,mechanical,and electrochemical characteristics of the alloys were evaluated using various advanced characterization *** showed that the alloys exhibited a dual-phase structure with dendritic *** inclusion of nb in the AlCrFeniCu alloy matrix promoted the formation of fine eutectic structures and changed the shape of the grains from columnar to *** Cu content decreased with the increase in the content of nb,whereas the Al content increased with the increase in the content of *** findings indicated that the presence of nb in the alloy promoted the formation and enhanced the stability of the body-centered cubic(bcc)*** of the alloys that contained nb also exhibited high hardness,compressive strength,and wear ***,the low current density and positive shift in potential exhibited by HEAs with appropriate addition of nb highlighted the superior anticorrosive properties.

关键词： high-entropy alloys microstructure microhardness friction wear loss corrosion resistance

Lattice thermal conduction in cadmium arsenide

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Chinese Physics B 2022年第11期31卷 424-430页

作者： R F Chinnappagoudra m D Kamatagi n R Patil n S Sankeshwar Department of Physics S.S.Government First Grade CollegeNargund-582207KarnatakaIndia Research Resource Centre Visvesvaraya Technological UniversityBelagavi-590018KarnatakIndia Department of Physics B V B College of Engineering and TechnologyHubliKarnataka 80031India Department of Physics&Electronics CHRIST(Deemed to be University)Bangalore-560029KarnatakaIndia

Lattice thermal conductivity(LTC)of cadmium arsenide(Cd_(3)As_(2))is studied over a wide temperature range(1–400 K)by employing the Callaway *** acoustic phonons are considered to be the major carriers of heat and to be scattered by the sample boundaries,disorder,impurities,and other phonons via both Umklapp and normal phonon *** calculations of LTC of Cd_(3)As_(2)bring out the relative importance of the scattering *** systematic analysis of recent experimental data on thermal conductivity(TC)of Cd_(3)As_(2)samples of different groups,presented in terms of LTC,κL,using a nonlinear regression method,reveals good fits to the TC data of the samples considered for Tnd suggests a value of 0.2 for the Gruneisen *** is,however,found that for T>100 K the inclusion of the electronic component of TC,κe,incorporating contributions from relevant electron scattering mechanisms,is needed to obtain good agreem.nt with the TC data over the wide temperature *** detailed investigations of TC of Cd_(3)As_(2)are required to better understand its suitability in thermoelectric and thermal managem.nt devices.

关键词： dirac semimetals Cd_(3)As_(2) thermal conductivity phonon scattering

A FLEXiBLE OBJECTiVE-COnSTRAinT APPROACH AnD A nEW ALGORiTHm FOR COnSTRUCTinG THE PARETO FROnT OF mULTiOBJECTiVE OPTimiZATiOn PROBLemS

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Acta mathematica Scientia 2024年第2期44卷 702-720页

作者： n.HOSEinPOOR m.GHAZnAVi Faculty of mathematical Sciences Shahrood University of TechnologyShahroodIran

in this article, a novel scalarization technique, called the improved objective-constraint approach, is introduced to find efficient solutions of a given multiobjective programming problem. The presented scalarized problem extends the objective-constraint problem. it is dem.nstrated that how adding variables to the scalarized problem, can lead to find conditions for (weakly, properly) Pareto optimal solutions. Applying the obtained necessary and sufficient conditions, two algorithms for generating the Pareto front approximation of bi-objective and three-objective programming problems are designed. These algorithms are easy to implem.nt and can achieve an even approximation of (weakly, properly) Pareto optimal solutions. These algorithms can be generalized for optimization problems with more than three criterion functions, too. The effectiveness and capability of the algorithms are dem.nstrated in test problems.

关键词： multiobjective optimization Pareto front scalarization objective-constraint approach proper efficient solution

Generation of dual and quad‑optical frequency combs in the injected radiation free mode‑locked frequency‑shifted feedback laser

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Frontiers of Optoelectronics 2023年第3期16卷 43-56页

作者： Sergey n.mantsevich Ekaterina i.Kostyleva Andrey n.Danilin Vladimir S.Khorkin Physics Department M.V.Lomonosov Moscow State UniversityMoscow 119991Russia Russian Quantum Center(RQC) Skolkovo 143026Russia

The results of an optoelectronic system—frequency-shifted feedback(FSF)laser experimental examination are *** considered FSF laser is seeded only with optical amplifer spontaneous emission(ASE)and operates in the mode-locked regime,whereby the output radiation is sequence of short pulses with a repetition rate determined by the delay time in its optical feedback *** the frequency domain,the spectrum of such a pulse sequence is an optical frequency comb(OFC).These OFCs we call *** consider the possibility of tunable acousto-optic(AO)dual and quad-comb frequency spacing downconversion in the FSF laser seeded with ASE and operating in the mode-locked *** examined system applies a single frequency shifting loop with single AO tunable flter as the frequency shifter that is fed with several radio frequency signals *** initial OFCs with frequency spacing of about 6.5 mHz may be obtained in the wide spectral range and their width,envelope shape and position in the optical spectrum may be *** dual-combs are obtained with a pair of initial OFCs aroused by two various ultrasound waves in the acousto-optic tunable flter(AOTF).The dual-combs frequency spacing is determined by the frequency diference of the signals applied to the AOTF piezoelectric transducer and can be tuned *** quad-combs are obtained with three initial OFCs,forming a pair of dual-combs,appearing when three ultrasound frequencies feed the AOTF *** quad-combs frequency spacing is defned by the diference between the frequency spacing of ***-combs with more than 5000 spectral lines and tunable frequency spacing are *** successive frequency downconversion gives the possibility to reduce the OFC frequency spacing form several mHz for initial OFC to tens of kHz for quad-combs.

关键词： Frequency-shifted feedback laser Optical frequency combs Acousto-optics Dual-combs Quad-combs

Optical negasensors and Prospects of Their Applications

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光学学报 2003年第S1期23卷 817-818页

作者： n.A.Filinyuk P.A.molchanov O.O.Lazarev i.m. Petrosyuk A.i.Luchenko Vinnitsya State Technical University 95 Khmelnitske shosse Vinnitsya 21021 UkraineVinnitsya State Technical University 95 Khmelnitske shosse Vinnitsya 21021 UkraineVinnitsya State Technical University 95 Khmelnitske shosse Vinnitsya 21021 UkraineVinnitsya State Technical University 95 Khmelnitske shosse Vinnitsya 21021 UkraineVinnitsya State Technical University 95 Khmelnitske shosse Vinnitsya 21021 Ukraine

The basic types of optical negasensors - sensors based on the application of negative resistance, negative inductance and negative capacitance, R, L, C-negatrons are presented. it is shown, that application of negative inductance and capacitance is not connected with stability decreasing as at application of negative resistance and allows to rise sensitivity of a optical sensor theoretically ad infinitum. The example design of multielem.nt optical negasensor for airborne, underwater or biomedical imagin...

关键词： of or as on in it Optical negasensors and Prospects of Their Applications mode

B(E2) value of even-even ^(108-112)Pd isotopes by interacting boson model-1

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Chinese Physics C 2014年第2期38卷 24-28页

作者： i.Hossain H.Y.Abdullah i.m.Ahmad m.A.Saeed Department of Physics Rabigh College of Science and Arts King Abdulaziz University Department of Physics College of Education Scientific Department Salahaddin University Department of Physics College of Education Mosul University Department of Physics Faculty of Science Universiti Teknologi Malaysia

This work studies the systematic reduced transition probabilities B（E2）↓, intrinsic quadrupole moments and deformation parameters of Pd isotopes with even neutrons from n =62 to 66. The downward reduced transition probabilities B（E2）↓from gamma transition 8^＋to 6^＋, 6^＋ to 4^＋, 4^＋ to 2^＋ and 2^＋ to 0＋states of even-even108 112Pd isotopes were calculated by the interacting Boson model（iBm-1） and compared with the available previous experimental results. The ratio of the excitation energies of the first 4＋and the first 2＋excited states, R4/2, is also studied for the classification of symmetry of these nuclei. Furthermore we have studied systematically the transition rate R = B（E2： L＋ →（L 2）＋）/B（E2 ： 2＋ →0＋） of some of the low-lying quadrupole collective states in comparison with the available experimental data. The associated quadrupole moments and deformation parameters have been calculated. The results of this calculation are in good agreem.nt with the corresponding available experimental data. The108 112Pd isotopes show the O（6） symmetry.

关键词： B(E2) ground-states Pd isotopes.quadrupole moments deformation parameter

Bipolar tri-state resistive switching characteristics in Ti/CeO_x/Pt memory device

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Chinese Physics B 2014年第12期23卷 333-338页

作者： m.ismail m.W.Abbas A.m.Rana i.Talib E.Ahmed m.Y.nadeem T.L.Tsai U.Chand n.A.Shah m.Hussain A.Aziz m.T.Bhatti Department of Physics Bahauddin Zakariya University Department of Electronics Engineering and institute of Electronics National Chiao Tung University Thin Films Technology Research Laboratory Department of Physics COMSATS Institute of Information Technology Center for High Energy Physics University of Punjab

Highly repeatable multilevel bipolar resistive switching in Ti/Ce Ox/Pt nonvolatile memory device has been dem.nstrated. X-ray diffraction studies of Ce O2 films reveal the formation of weak polycrystalline structure. The observed good memory performance, including stable cycling endurance and long data retention times（〉10^4s） with an acceptable resistance ratio（～10^2）, enables the device for its applications in future non-volatile resistive random access memories（RRams）. Based on the unique distribution characteristics of oxygen vacancies in Ce Ox films, the possible mechanism of multilevel resistive switching in Ce Ox RRam devices has been discussed. The conduction mechanism in low resistance state is found to be Ohmic due to conductive filamentary paths, while that in the high resistance state was identified as Ohmic for low applied voltages and a space-charge-limited conduction dominated by Schottky emission at high applied voltages.

关键词： multilevel resistive switching Schottky emission cerium oxide oxygen vacancy