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Effect of divalent cations(Co^(2+) and Ni^(2+)) on microstructure,physical properties and application of NdFeO_(3)

Journal of Rare Earths 2025年第1期43卷 89-97,I0004页

作者： M.M.Arman Materials Science Lab(1. Physics DepartmentFaculty of ScienceCairo UniversityGiza12613Egypt

The nanocrystalline samples Nd_(1.x)M_(x)FeO_(3)(x=0.0 and 0.1.M:Co^(2+)and Ni^(2+))were prepared using the citrate combustion *** X-ray diffraction(XRD)pattern confirmed that the nanoparticles were synthesized in an orthorhombic *** particle size of Nd_(1.x)M_(x)FeO_(3) is in the range of 29-59 *** selected area electron diffraction(SAED)indicates the samples were prepared in a polycrystalline *** samples Nd_(1.x)M_(x)FeO_(3)(x=0.0 and 0.1.M:Co^(2+)and Ni^(2+))have anti ferromagnetic *** Fe^(3+)spins are aligned antiparallel,forming the antiferromagnetic(AFM)properties,which are affected by many factors such as the bond angle between the Fe^(3+)(Fe^(3+)-O_(2)--Fe^(3+))and the Dzyaloshinskii-Moriya(D-M)*** doping of Co^(2+)and Ni^(2+)ions in NdFeO_(3) enhances the magnetic properties of the NdFeO_(3).The saturation magnetization(Ms)of Nd_(0.90)Co_(0.1.)FeO_(3) increases 1.8times more than that of NdFeO_(3).The exchange bias field(HEX)of the Co-doped sample is two times greater than that of NdFeO_(3).The magnetic anisotropy constant(K)of the 1.%Co-doped sample increases by 1. factors compared to that of NdFeO_(3).The Tauc plot illustrates that the samples have a direct optical *** divalent cation substitution(Co^(2+)and Ni^(2+))decreases the optical band gap of NdFeO_(3),leading to the recommendation of using the samples Nd_(0.90)Co_(0.1.)FeO_(3) and Nd_(0.90)Ni_(0.1.)FeO_(3) in photocatalysis of dye degradation from *** removal efficiencies of Cr6+at pH=6 are 88.06%,85.54%,and 85.52%for the samples NdFeO_(3),Nd_(0.90)Co_(0.1.)FeO_(3),and Nd_(0.90)Ni_(0.1.)FeO_(3),*** Freundlich isotherm mode is the best-fit model for NdFeO_(3) to adsorb Cr6+ions from aqueous solutions.

关键词： Optical properties Nanoparticles Magnetic properties Perovskites Removal efficiency Rareearths

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Testing the Effects of Cosmic Ray Flux Intensity Modulation on Solar Emission Characteristics

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Research in Astronomy and Astrophysics 2025年第03期25卷 157-178页

作者： Costecia Ifeoma Onah Ogbonnaya Okike Jibrin A.Alhassan Firew M.Menteso Romanus E.Ugwoke Evaristus U.Iyida department of {1. Federal University of Technology department of Industrial {1. Ebonyi State University department of {1. and Astronomy University of Nigeria department of {1. Jinka University

We investigate the relationship between the magnitudes of Forbush decreases (FDs) and solar-geomagnetic characteristics using daily-averaged galactic cosmic ray (GCR) data from Inuvick (INVK) and Magadan (MGDN)neutron monitor (NM) stations to aid in counting the case of GCR flux intensity *** FDs,obtained with an automated new computer software algorithm from daily-averaged GCR data from the IZMIRAN common website:http://***/common,at INVK (224) and MGDN (229) NM stations,from 1.98 to 2002,were used in the present *** associated solar-geomagnetic parameters of the same time range were obtained from the OMNI website.A statistical analytical method was employed to test the link between FD amplitudes and solargeomagnetic *** observed negative trends in FD-IMF,FD-SWS,FD-Kp,FD-SSN and FD-SI,while a positive relation was indicated in FD-Dst at both *** are statistically significant at a 95%confidence *** results obtained here imply that solar emission characteristics impact the GCR flux intensity modulation.

关键词： (ISM:) cosmic rays (Sun:) solar wind (Sun:) solar-terrestrial relations methods: data analysis methods: statistical Sun: coronal mass ejections (CMEs)

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The Vela Supernova Remnant: The Unique Morphological Features of Jittering Jets

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Research in Astronomy and Astrophysics 2025年第03期25卷 70-78页

作者： Noam Soker Dmitry Shishkin department of {1. Technion

We identify an S-shaped main-jet axis in the Vela core-collapse supernova remnant(CCSNR) that we attribute to a pair of precessing jets, one of the tens of pairs of jets that exploded the progenitor of Vela according to the jittering jets explosion mechanism(JJEM). A main-jet axis is a symmetry axis across the CCSNR and through the *** identify the S-shaped main-jet axis by the high abundance of ejecta elements, oxygen, neon, and *** bring the number of identified pairs of clumps and ears in Vela to seven, two pairs shaped by the pair of precessing jets that formed the main-jet axis. The pairs and the main-jet axis form the point-symmetric wind-rose structure of Vela. The other five pairs of clumps/ears do not have signatures near the center, only on two opposite sides of the CCSNR. We discuss different possible jet-less shaping mechanisms to form such a point-symmetric morphology and dismiss these processes because they cannot explain the point-symmetric morphology of Vela, the S-shaped high ejecta abundance pattern, and the enormous energy required to shape the S-shaped structure. Our findings strongly support the JJEM and further severely challenge the neutrino-driven explosion mechanism.

关键词： (stars:) supernovae: general (stars:) supernovae: individual (Vela) ISM: supernova remnants stars: jets stars: massive stars: neutron

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On the Response of Massive Main Sequence Stars to Mass Accretion and Outflow at High Rates

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Research in Astronomy and Astrophysics 2025年第2期25卷 95-102页

作者： Ealeal Bear Noam Soker department of {1. Technion

With a one-dimensional stellar evolution model, we find that massive main sequence stars can accrete mass at very high mass accretion rates without expanding much if they lose a significant fraction of this mass from their outer layers simultaneously with mass accretion. We assume the accretion process is via an accretion disk that launches powerful jets from its inner zones. These jets remove the outer high-entropy layers of the mass-accreting star. This process operates in a negative feedback cycle, as the jets remove more envelope mass when the star expands. With the one-dimensional model, we mimic the mass removal by jets by alternating mass addition and mass removal phases. For the simulated models of 30M☉and 60M☉, the star does not expand much if we remove more than about half of the added mass in not-too-short episodes. This holds even if we deposit the energy the jets do not carry into the envelope. As the star does not expand much, its gravitational potential well stays deep, and the jets are energetic. These results are relevant to bright transient events of binary systems powered by accretion and the launching of jets, e.g., intermediate luminosity optical transients, including some luminous red novae, the grazing envelope evolution, and the 1.37–1.56 Great Eruption of Eta Carinae.

关键词： stars: jets stars: mass-loss stars: massive

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Conformation and Dynamics of a Long Active Polymer Chain Confined in a Circular Cavity

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Chinese Journal of Polymer Science 2025年第1期43卷 225-234,I0014页

作者： Xiao Yang Yan-Li Zhou Bin Zhao Chao Wang Meng-Bo Luo department of {1. Taizhou UniversityTaizhou318000China department of {1. Zhejiang UniversityHangzhou310027China

The conformational and dynamical properties of a long semi-flexible active polymer chain confined in a circular cavity are studied by using Langevin dynamics simulation *** show that the steady radius of gyration of the polymer decreases monotonically with increasing the active ***,the polymer forms stable compact spiral with directional rotation at the steady state when the active force is *** the radius of gyration and the angular velocity of the spiral are nearly independent of the cavity size,but show scaling relations with the active force and the polymer *** is further found that the formation of the stable compact spiral in most cases is a two-step relaxation process,where the polymer first forms a metastable swelling quasi spiral and then transforms into the stable compacted spiral near the wall of the *** relaxation time is mainly determined by the transformation of the swelling quasi spiral,and shows remarkable dependence on the size of the ***,when the circumference of the circular is nearly equivalent to the polymer length,it is difficult for the polymer to form the compacted spiral,leading to a large relaxation *** underlying mechanism of the formation of the compacted spiral is revealed.

关键词： Active polymer Confinement Configuration Dynamics Simulation

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Studying Thermal and Dynamical Stability of Interacting Rényi and Tsallis Holographic Dark Energy Models in LTB Inhomogeneous Universe

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Research in Astronomy and Astrophysics 2025年第2期25卷 112-125页

作者： Mohamed Abdelrashied Ayman Aly Mustafa Selim physics {1. Faculty of Science Damietta University physics {1. Faculty of Science Damanhour University

This work aims to investigate the different stability conditions of two scenarios of the inhomogeneous Lemaitre–Tolman–Bond model of the universe with holographic dark energy. We considered the Rényi and Tsallis holographic models of interacting dark energy. These holographic models are investigated using the IR cutoff that equals the Hubble horizon. Various stability conditions of these models have been investigated to understand how much these models can tell us about the recent and future epochs of the universe in comparison with the cosmological constant model, orΛCDM model. The conditions of violating the cosmological energy conditions have been studied. The evolution of the entropy and its first and second derivatives have been calculated and plotted for these holographic models. This gives an idea of how far these models satisfy the generalized second law of thermodynamics and hence have thermodynamical stability. The dynamical stability is studied for these evolved models, which give us glimpses of the dynamical stability at different phases of its evolution. We focus on investigating the stability in recent and near future times up to z≤-4. Further investigation of stability has been obtained by studying the evolved sound speed squared parameter for these models, which gave us a final and decisive evaluation of the stability of these models.

关键词： (cosmology:) cosmological parameters (cosmology:) dark energy (cosmology:) large-scale structure of universe cosmology: theory

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p-wave mesons emitting weak decays of bottom mesons

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Chinese physics C 2025年第2期49卷 51-63页

作者： Maninder Kaur Supreet Pal Singh R.C.Verma department of {1. Punjabi University

This paper is the extension of our previous work entitled "Searching a systematics for nonfactorizable contributions to B-and ■ hadronic decays".Obtaining the factorizable contributions from the spectator-quark model for Nc=3,a systematic s was identified among the iso spin reduced amplitudes for the nonfactorizable terms among ■→Dπ/D*π/Dρ decay *** systematics enables us to derive a generic formula to help predict the branching fractions for ■-*** by this observation,we extend our analysis to p-wave meson emitting decays of B-meson ■→PA/PT/PS,particularly ■→a1./πD1.πD'1.πrD2/πD0,which have similar isospin structures and make predictions for B0-decays,for which experimental measurements are not yet available.

关键词： non factorization in B meson decays p-wave mesons weak hadronic decays

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Reducing the measurement errors in nonadiabatic holonomic quantum computers

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Science China(physics,Mechanics & Astronomy) 2025年第1期68卷 60-66页

作者： Guo-Fu Xu department of {1. Shandong UniversityJinan 250100China

Nonadiabatic holonomic quantum computers serve as the physical platform for nonadiabatic holonomic quantum *** quantum computation has entered the noisy intermediate-scale era,building accurate intermediate-scale nonadiabatic holo-nomic quantum computers is clearly *** that measurements are the sole means of extracting information,they play an indispensable role in nonadiabatic holonomic quantum ***,developing methods to reduce measurement errors in nonadiabatic holonomic quantum computers is of great ***,while much attention has been given to the research on nonadiabatic holonomic gates,the research on reducing measurement errors in nonadiabatic holonomic quantum computers is severely *** this study,we propose a measurement error reduction method tailored for intermediate-scale nonadiabatic holonomic quantum *** reason we say this is because our method can not only reduce the measurement errors in the computer but also be useful in mitigating errors originating from nonadiabatic holonomic *** these features,our method significantly advances the construction of accurate intermediate-scale nonadiabatic holonomic quantum computers.

关键词： quantum holonomy quantum computation measurement errors

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Hawking radiation and Page curve of regular black holes

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Chinese physics B 2025年第2期34卷 178-187页

作者： Chen-Yang Dong Li-Jun Tian department of {1. Shanghai UniversityShanghai 200444China

We discuss the information paradox and its implications for regular black holes. Our primary focus is on Page curve using the island treatment and analyzing relevant parameters like Page time and scrambling time. Calculations without considering the island show that the entanglement entropy increases linearly and continues to infinity. When we consider the generalized entropy, we find that the island extends just beyond the horizon, leading to a constant entanglement ***, we find that in the early stages, the island never forms, regardless of the charge and mass configuration of the black hole.

关键词： black holes AdS/CFT correspondence Page curve

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Density distribution of ground state of one-dimensional Bose gas with dipole interaction

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Chinese physics B 2025年第3期34卷 245-249页

作者： Shuchang Hao Yajiang Hao department of {1. and Institute of Theoretical {1. University of Science and Technology BeijingBeijing 100083China

Using the Bose-Fermi mapping method,we obtain the exact ground state wavefunction of one-dimensional(1.)Bose gas with the zero-range dipolar interaction in the strongly repulsive contact interaction *** ground state density distributions for both repulsive and attractive dipole interactions are *** is shown that in the case of the finite dipole interaction the density profiles do not change obviously with the increase of dipole interaction and display the typical shell structure of Tonks-Girardeau *** the repulsive dipole interaction is greatly strong,the density decreases at the center of the trap and displays a sunken *** the attractive dipole interaction increases,the density displays more oscillations and sharp peaks appear in the strong attraction limit,which mainly originate from the atoms occupying the low single particle levels.

关键词： Bose gas one-dimensional dipole interaction

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