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magnetic,dielectric and electrical modulus of Ce^(3+) doped cobalt-magnesium ferrite nanoparticles

Journal of Rare Earths 2024年第2期42卷 373-382,I0005页

作者： n.m.Basfer Hanaa Almaghamsi Department of Physics Umm AL-Qura UniversityMakkahSaudi Arabia Physics Department College of Science and ArtKing Abdulaziz UniversityPOB344Rabigh291Saudi Arabi

In this work,the magnetic,dielectric properties and electric modulus of Ce^(3+) substituted cobaltmagnesium(Co_(0.7)mg_(0.3)Ce_(x)Fe_(2-x)O_4)(labeled as CmCF) ferrite nanoparticles were investigated in detail.Saturation magnetization decreases from 50.05 to 34.87 emu/g for further substituting Ce^(3+) ions.meanwhile,coercivity increases from 738.22 Gs for the CmCFO sample to 912.10 Gs for the CmCF2 sample,then decreases monotonically to 762.1 Gs for the CmCF5 sample.The cerium content and particle size play important roles in controlling the magnetization and coercivity of the CmCF nanoparticles.All CmCF nanoferrites are suitable for microwave applications since their high-frequency response ranges from 7.72 to 11.07 GHz.The CmCF nanoferrites' dielectric parameter dispersion exhibits normal behavior.The pristine Co-mg nanoferrite only has ε' value of 28.25,but the nanoferrite mCmF2 has ε' value of365.03,with an enhancing ratio of 1192%.The conduction mechanism of the mCmF nanoferrites was determined by fitting the σ_(ac) results via the Jonscher power law.At 653 K,large polaron tunnelling is thought to be responsible for this conduction process,which is followed by electron barrier hopping at higher temperatures.Cole-Cole diagrams at different temperatures,assuring the contributions of the grains and their boundaries at lower temperatures(653 K) and only the grains at higher temperatures.Based on our results,the CmCF nanoferrites hold magnetic and semiconducting nature,which can be used in magnetic devices and dielectrics in lower-frequencies or conductors in higher-frequencies.

关键词： nanoferrites Rare earth ions magnetic properties Dielectric parameters Impedance spectroscopy

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EDSUCh:A robust ensemble data summarization method for effective medical diagnosis

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Digital Communications and networks 2024年第1期10卷 182-189页

作者： mohiuddin Ahmed A.n.m.Bazlur Rashid School of Science Edith Cowan UniversityPerthAustralia

Identifying rare patterns for medical diagnosis is a challenging task due to heterogeneity and the volume of data.Data summarization can create a concise version of the original data that can be used for effective diagnosis.In this paper,we propose an ensemble summarization method that combines clustering and sampling to create a summary of the original data to ensure the inclusion of rare patterns.To the best of our knowledge,there has been no such technique available to augment the performance of anomaly detection techniques and simultaneously increase the efficiency of medical diagnosis.The performance of popular anomaly detection algorithms increases significantly in terms of accuracy and computational complexity when the summaries are used.Therefore,the medical diagnosis becomes more effective,and our experimental results reflect that the combination of the proposed summarization scheme and all underlying algorithms used in this paper outperforms the most popular anomaly detection techniques.

关键词： Data summarization Ensemble medical diagnosis Sampling

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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 demonstrated 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 implement 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 demonstrated in test problems.

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

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Characterization of bright betatron radiation generated by direct laser acceleration of electrons in plasma of near critical density

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matter and Radiation at Extremes 2024年第2期9卷 26-35页

作者： J.Cikhardt m.Gyrdymov S.Zähter P.Tavana m.m.Günther n.Bukharskii n.Borisenko J.Jacoby X.F.Shen A.Pukhov n.E.Andreev O.n.Rosmej Faculty of Electrical Engineering Czech Technical University in Prague16627 Prague 6Czech Republic Goethe University FrankfurtMax-von-Laue-Straße 160438 Frankfurt am MainGermany GSI Helmholtzzentrum für Schwerionenforschung GmbH Planckstraße 164291 DarmstadtGermany Focused Energy GmbH Im Tiefen See 4564293 DarmstadtGermany national Research nuclear University mEPhI Kashirskoe shosse 31115409 MoscowRussian Federation Lebedev Physical Institute RAS Leninskiy Prospekt 53119991 MoscowRussian Federation Heinrich-Heine-University Düsseldorf Universitätsstrasse 1DüsseldorfGermany Joint Institute for High Temperatures RASIzhorskaya st.13Bldg.2125412 MoscowRussian Federation moscow Institute of Physics and Technology Institutskiy Pereulok 9141700 DolgoprudnyRussia

Directed x-rays produced in the interaction of sub-picosecond laser pulses of moderate relativistic intensity with plasma of near-critical density are investigated. Synchrotron-like (betatron) radiation occurs in the process of direct laser acceleration (DLA) of electrons in a relativisticlaser channel when the electrons undergo transverse betatron oscillations in self-generated quasi-static electric and magnetic fields. In anexperiment at the PHELIX laser system, high-current directed beams of DLA electrons with a mean energy ten times higher than the ponderomotive potential and maximum energy up to 100 meV were measured at 10^(19) W/cm^(2)laser intensity. The spectrum of directed x-raysin the range of 5–60 keV was evaluated using two sets of Ross filters placed at 0°and 10°to the laser pulse propagation axis. The differential x-ray absorption method allowed for absolute measurements of the angular-dependent photon fluence. We report 10^(13) photons/sr withenergies >5 keV measured at 0°to the laser axis and a brilliance of 10^(21) photons s^(−1) mm^(−2) mrad−2(0.1%BW)−1. The angular distributionof the emission has an FWHm of 14°–16°. Thanks to the ultra-high photon fluence, point-like radiation source, and ultra-short emissiontime, DLA-based keV backlighters are promising for various applications in high-energy-density research with kilojoule petawatt-class laserfacilities.

关键词： laser acceleration critical

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Radiation of a Tm mode from an open end of a three-layer dielectric capillary

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Chinese Physics B 2024年第7期33卷 321-329页

作者： Sergey n.Galyamin Alexandr m.Altmark St. Petersburg State University St. Petersburg Electrotechnical University “LETI”

modern trends in beam-driven radiation sources include the interaction of Cherenkov wakefields in open-ended circular waveguides with complicated dielectric linings, with a three-layer dielectric capillary recently proposed to reduce radiation divergence being a representative example [Opt. Lett. 45 5416(2020)]. We present a rigorous approach that allows for an analytical description of the electromagnetic processes that occur when the structure is excited by a single waveguide Tm mode. In other words, the corresponding canonical waveguide diffraction problem is solved in a rigorous formulation. This is a continuation of our previous papers which considered simpler cases with a homogeneous or two-layer dielectric filling. Here we use the same analytical approach based on the Wiener–Hopf–Fock technique and deal with the more complicated case of a three-layer dielectric lining. Using the obtained rigorous solution, we discuss the possibility of manipulating the far-field radiation pattern using a third layer made of a low permittivity material.

关键词： Circular waveguides

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Changes in children’s cardiorespiratory fitness and body mass index over the course of the COVID‑19 pandemic:a 34‑month longitudinal study of 331 primary school children

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World Journal of Pediatrics 2024年第2期20卷 185-188页

作者： Gerald Jarnig Reinhold Kerbl mireille n.m.van Poppel Institute of Human movement Science Sport and HealthUniversity of GrazMozartgasse 148010 GrazAustria Department of Pediatrics and Adolescent medicine LKH Hochsteiermark8700 LeobenAustria

In late 2019,heavy restrictions were enforced on public activities worldwide to diminish the spread of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)virus[1].These restrictions,which included school closures and strictly limited sports and leisure opportunities,particularly impacted children and adolescents[2].Lifestyle changes in children and adolescents led to reduced physical activity levels[2,3],increased sedentary behavior[3,4],changes in eating habits,and changes in sleep habits[3].

关键词： respiratory acute children

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Inclusion of CoTiO_(3) to ameliorate the re/dehydrogenation properties of the mg–na–Al system

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Journal of magnesium and Alloys 2024年第3期12卷 1215-1226页

作者： n.A.Ali n.Y.Yusnizam n.A.Sazelee Sami-ullah Rather Haizhen Liu m.Ismail Energy Storage Research Group Faculty of Ocean Engineering TechnologyUniversiti Malaysia Terengganu21030 Kuala NerusTerengganuMalaysia Department of Chemical and materials Engineering King Abdulaziz UniversityP.O.Box80204Jeddah 21589Saudi Arabia Guangxi novel Battery materials Research Center of Engineering Technology School of Physical Science and TechnologyGuangxi UniversityNanning 530004China State Key Laboratory of Featured metal materials and Life-Cycle Safety for Composite Structures Nanning 530004China

For the first time,the mgH_(2)–naAlH_(4)(ratio 4:1)destabilized system with CoTiO_(3) addition has been explored.The CoTiO_(3)-doped mgH_(2)–naAlH_(4) sample begins to dehydrogenate at 130℃,which is declined by 40℃ compared to the undoped mgH_(2)–naAlH_(4).moreover,the de/rehydrogenation kinetics characteristics of the CoTiO_(3)-doped mgH_(2)–naAlH_(4) were greatly ameliorated.With the inclusion of CoTiO_(3),the mgH_(2)–naAlH_(4) composite absorbed 5.2 wt.%H_(2),higher than undoped mgH_(2)–naAlH_(4).In the context of dehydrogenation,the CoTiO_(3)-doped mgH_(2)–naAlH_(4) sample desorbed 2.6 wt.%H_(2),almost doubled compared to the amount of hydrogen desorbed from the undoped mgH_(2)–naAlH_(4) sample.The activation energy obtained by the Kissinger analysis for mgH_(2) decomposition was significantly lower by 35.9 kJ/mol than the undoped mgH_(2)–naAlH_(4) sample.The reaction mechanism demonstrated that new phases of mgCo and AlTi_(3) were generated in situ during the heating process and are likely to play a substantial catalytic function and be useful in ameliorating the de/rehydrogenation properties of the destabilized mgH_(2)–naAlH_(4) system with the inclusion of CoTiO_(3).

关键词： Destabilize system magnesium hydride Sodium alanate Hydrogen storage Additive.

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Empirical model for fusion cross sections of Ca-induced reactions

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Chinese Physics C 2024年第3期48卷 126-132页

作者： Reddi Rani.L n.Sowmya K.n Sridhar H C.manjunatha m.m.Armstrong Arasu Department of Physics St.Joseph's College(Autonomous)Affiliated to Bharathidasan UniversityTiruchirappalli620002TNIndia Department of Physics Govt.First.Grade CollegeChikkaballapur-562101KarnatakaIndia Department of Physics Govt.First.Grade CollegeMalur-563160KarnatakaIndia Department of Physics Govt.First.Grade CollegeDevanahalli-562110KarnatakaIndia

A new empirical formula for the astrophysical S-factor has been suggested as a function of the Coulomb interaction parameter,center of mass energy,and barrier height.About 22 fusion reactions with ^(40,48)Ca as projectiles were considered for different targets,leading to compound nuclei with atomic and mass numbers varying between 40≤Z≤≤Z≤112 and 88≤A≤27888≤A≤278,respectively.The fusion cross-sections have been estimated using the geometric factor,the Gamow-Sommerfield factor,and the empirical formula for the S-factor.This study's findings showed better agreement with those of available experiments when compared to Wong's formula.The present work leads to a smaller standard deviation value than Wong's formula when used to correlate the experimental data of calcium-induced fusion reactions.Wong's formula provides a good approximation of fusion cross-sections when the center of mass energy is below the fusion barrier when compared to above the fusion barrier.

关键词： fusion cross-sections Wong formula Gamow-Sommerfield-factor Geometric-factor S-factor

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Direct microwave leaching conditions of rare earth elements in fluorescent wastes

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Journal of Rare Earths 2024年第6期42卷 1165-1174,I0007页

作者： A.Bilen B.Birol m.n.Saridede S.S.Kaplan m.S.Sonmez Department of metallurgical and materials Engineering Yildiz Technical UniversityIstanbulTurkey Department of Chemical Engineering and materials Science Stevens Institute of TechnologyNew JereyUSA Department of metallurgical and materials Engineering Istanbul Technical UniversityIstanbulTurkey

The luminescent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s weight.It can be mentioned that fluorescent wastes are a crucial raw material to produce rare earth oxides.In the present study,microwave leaching process was conducted to dissolve rare earth elements yttrium(Y),europium(Eu),and remaining rare earth elements(REEs)present in the phosphor powder of the fluorescent lamp.and the yields were compared.In the microwave leaching process,the effects of the temperature(80-160℃),acid type(hydrochloric acid(HCl),nitric acid(HnO_(3)),sulphuric acid(H_(2)SO_(4))),acid concentration(0.5-6 mol/L),solid to liquid ratio(0.1:10-0.5:10)and reaction time(5-90 min)parameters on leaching efficiencies of varying rare earth elements and calcium were investigated.The highest yield was obtained in the direct microwave leaching of fluorescent waste with the experimental conditions of 6 mol/L HCl,160℃,0.1:10 solid-to-liquid ratio(S:L),and 90 min.Activation energy calculations were made,and kinetic models of the reactions were obtained,and it is observed that Y and Eu dissolution is diffusion-controlled,on the other hand,lanthanum(La),cerium(Ce),and terbium(Tb)were examined to be chemical reaction controlled.moreover,calcium(Ca)and gadolinium(Gd)seem coherent with the mixed model.Concurrently,mathematical models of all experimental studies are created with the response surface Box-Behnken method and the correlation coefficients of all the models are over 90%.

关键词： Rare earth elements(REEs) Direct microwave leaching Fluorescent waste Kinetic models Response surface method

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nanomotion of bacteria to determine metabolic profile

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nanotechnology and Precision Engineering 2024年第1期7卷 1-9页

作者： S.n.Pleskova E.V.Lazarenko n.A.Bezrukov R.n.Kriukov A.V.Boryakov m.E.Dokukin S.I.Surodin Research Laboratory of Scanning Probe microscopy Lobachevsky State University of Nizhny NovgorodNizhny Novgorod 603950Russia Department of nanotechnology and Biotechnology Nizhny Novgorod State Technical University n.a.R.E.AlekseevNizhny Novgorod 603950Russia Sarov Physics and Technology Institute National Research Nuclear University MEPhISarov 607186Russia

In addition to their visible motion such as swimming(e.g.,with the help ofﬂagella),bacteria can also exhibit nanomotion that is detectable only with highly sensitive instruments,and this study shows that it is possible to detect bacterial nanomotion using an AFm detection system.The results show that the nanomotion characteristics depend on the bacterial strain,and that nanomotion can be used to sense the metabolic activity of bacteria because the oscillations are sensitive to the food preferences of the bacteria and the type of surrounding medium.

关键词： nanomotion Bacteria Cantilever Oscillation Atomic force microscopy metabolism

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