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Effect of Eu-Er substitution on structural,optical,dielectric,and electrical properties of Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) hexaferrite

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Journal of Rare Earths 2025年第1期43卷 115-123,I0005页

作者： Jayashri Mahapatro Sher Singh Meena Sadhana Agrawal Department of physics National Institute of Technology RaipurRaipur492010India Solid State physics division Bhabha Atomic Research CentreMumbai400085MSIndia

The present work reports the structural,optical,dielectric,and electrical properties of Eu-Er substituted M-type Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19)(x=0.0.05,0.1,0.15,and 0.2)hexaferrites synthesized by sol-gel combustion *** hexagonal structure of the Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) samples was confirmed from X-ray diffraction(XRD)*** values of lattice parameters of the Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19)samples are increased as compared to Ba_(0.5)Sr_(0.5)Fe_(12)O_(19) *** increase in the value of lattice parameters is attributed to the substitution of larger cations(Eu^(3+)and Er^(3+))in place of smaller cations(Fe^(3+)ions).The crystallite sizes of the Ba0.5Sr0.5EuxErxFe12-2x019 samples also increase due to the substitution of larger *** force constants(K_o and K_t)increases with increasing Eu-Er *** octahedral cluster shifts towards the higher wavenumber side whereas the tetrahedral cluster shifts towards the lower wavenumber side due to Eu-Er substitution in the Fourier transform infrared(FTIR)*** photoluminescence(PL)emission spectra for the Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) samples are observed at 365 *** dielectric dispersion in the Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) samples can be understood by Koop's theory and Maxwell-Wagner type of inte rfacial *** Jonscher's power law and the co rrelated barrier hopping(CBH)model,the frequency and temperature-dependent be haviour of ac conductivity of Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) samples are *** temperature-dependent behaviour of the dc conductivity of the Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) samples is explained by the variable range hopping(VRH)*** Motto temperature of the sample varies from 4.55×10^(9) to 2.31×10^(8) *** estimated maximum barrier height(WM)of the compound varies from 0.6603 to 0.1199 *** temperature coefficient and activation energy

关键词： Sol-gel process Porosity Dielectric properties Ferrites Rare earths

Constraints on holographic QCD phase transitions from PTA observations

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Science China(physics,Mechanics & Astronomy) 2025年第1期68卷 67-74页

作者： Song He Li Li Sai Wang Shao-Jiang Wang Center for Theoretical physics and College of physics Jilin UniversityChangchun 130012China School of Physical Science and Technology Ningbo UniversityNingbo 315211China CAS Key Laboratory of Theoretical physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Fundamental physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of Sciences(UCAS)Hangzhou 310024China Theoretical physics division Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China School of Physical Sciences University of Chinese Academy of Sciences(UCAS)Beijing 100049China Max Planck Institute for Gravitational physics(Albert Einstein Institute) Am Muhlenberg 1Golm 14476Germany

The underlying physics of QCD phase transition in the early Universe remains largely unknown due to its strong-coupling nature during the quark-gluon plasma/hadron gas transition,yet a holographic model has been proposed to quantitatively fit the lattice QCD data while with its duration of the first-order phase transition(FoPT)left *** specific baryon chemical poten-tial,the first-order QCD phase transition agrees with the observational constraint of baryon ***,therefore,provides a scenario for phase transition gravitational waves(GWs)within the standard model of particle *** these background GWs could contribute dominantly to the recently claimed common-spectrum red noise from pulsar timing array(PTA)observations,the duration of this FoPT can be well constrained,and the associated primordial black holes are still allowed by current observations.

关键词： pulsar timing array QCD phase transition gravitational waves primordial black holes

Potassium ion doped manganese oxide nanoscrolls enhanced the performance of aqueous zinc-ion batteries

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Chinese Chemical Letters 2025年第1期36卷 549-555页

作者： Yang Li Xiaoxu Liu Tianyi Ji Man Zhang Xueru Yan Mengjie Yao Dawei Sheng Shaodong Li Peipei Ren Zexiang Shen Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials School of Material Science and EngineeringShaanxi University of Science and TechnologyXi’an 710021China division of physics and Applied physics School of Physical and Mathematical SciencesNanyang Technological UniversitySingapore 637371Singapore

α-MnO_(2) is a potential positive electrode material for aqueous zinc-ion batteries,but its electrochemical performance of zinc storage requires further *** this paper,potassium ion-doped manganese dioxide nanoscrolls(K-MnO_(2))with oxygen vacancy were synthesized by a one-step hydrothermal *** was observed that the electrochemical specific capacity was 250.9 m Ah/g at a current density of 0.2 C,which was better than the existing commercialα-MnO_(2).At a high current of 1 C,these batteries demonstrate improved cycle *** radiation and other experiments as well as DFT theoretical calculations provided additional evidence that K doping was efficient in regulating the metal bond type and the mean charge regulation of covalent bonds with oxygen atoms in MnO_(2).When Mn-O and Mn-K bonds are present,K-MnO_(2) showed outstanding adsorption of Zn~(2+)and further enhanced the Zn^(2+)embedding ***,oxygen defects caused by doping boosted the development of the nanoscroll structure,leading to an increase in active sites available for electrochemical reactions and subsequently enhancing the electrical conductivity ofα-MnO_(2).This study exhibits the potential of optimizing materials based on manganese with the introduction of a potassium doping strategy,resulting in improved performance for aquatic zinc-ion batteries,and presents novel perspectives for related research.

关键词： Manganese dioxide K^(+) doping Nanoscrolls XAFS Aqueous zinc-ion batteries

In Vivo Research of Time-Lapse Changes on Surgical Sutures by OCT Signal Analysis

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Optics and Photonics Journal 2025年第1期15卷 1-8页

作者： Fengcheng Wei Hinata Nakakubo Nene Amishiro Masato Ohmi Biomedical Optics Laboratory Department of Medical Physics and Engineering Division of Health Sciences Graduate School of Medicine Osaka University Osaka Japan

Currently, animal and clinical research on biomaterials, such as surgical sutures, are mainly performed by removing them from the experiment targets and observing them by microscopy. However, traditional microscopy is not able to observe the internal structure, and there is a risk of sacrificing animals to remove the suture and damaging the materials. Therefore, we introduced optical coherence tomography (OCT) to observe and evaluate four different kinds of surgical sutures in vivo (monofilament absorbable and nonabsorbable sutures and braided absorbable and nonabsorbable sutures). As a result, while the monofilament nonabsorbable sutures showed almost no change over time, the absorbable sutures had color fading and it was also confirmed that the internal structure became chaotic due to decomposition, which improved the OCT signal intensity. For the braided sutures, both absorbable and nonabsorbable, we found that the reflection signal improved from week 0 because blood got among the filaments of sutures and dried during recovery which increased OCT signal from week 0 to week 1. We also confirmed that the braided sutures untwisted over time. All four kinds of sutures were pulled due to the movement of rats during recovery. It is expected that OCT technology will be of great help in in vivo experiments on biomaterials such as sutures.

关键词： Optical Coherence Tomography Surgical Suture Biomedical PLA/PCL PVDF PGA PEs In Vivo Animal Experiment

Sudden change of interferometric power for X-shape states

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Chinese physics B 2025年第2期34卷 133-139页

作者： Dian Zhu Fu-Lin Zhang Jing-Ling Chen Theoretical physics division Chern Institute of MathematicsNankai UniversityTianjin 300071China Department of physics School of ScienceTianjin UniversityTianjin 300072China

Quantum interferometric power(IP), a discordlike measure, plays an important role in quantum metrology. We study the dynamics of IP for two-qubit X-shape states under different noisy environments. Our study shows that IP exhibits sudden change, and one side quantum channel is enough for the occurrence of a sudden change of IP. In particular, we show that the initial state having no sudden change of quantum discord exhibits a sudden change of IP under the dynamics of amplitude noise, but the converse is not true. Besides, we also investigate the dynamics of IP under two different kinds of composite noises. Our results also confirm that sudden change of IP occurs under such composite noises.

关键词： quantum interferometric power quantum noise sudden change

Multi-dimensional Bi@C electrocatalyst for Cr3+/Cr2+ redox reaction boosting high-performance iron-chromium flow batteries

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Science China Chemistry 2025年

作者： Min Wu Mingjun Nan Shumin Liu Caihe Zhong Lin Qiao Huamin Zhang Xiangkun Ma Department of Materials Science and Engineering Dalian Maritime University division of Energy Storage Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences

With the increasing demand for energy storage technology, iron-chromium flow batteries（ICFBs） have been widely concerned because of their price advantage. However, the low electrochemical activity of Cr3+/Cr2+redox couples and the side hydrogen evolution reaction limit the industrial application of ICFBs. A multi-dimensional Bi/carbon composite electrocatalyst（Bi@C）for ICFB is designed and prepared to improve the electrochemical activity of Cr3+/Cr2+redox couples. Benefiting by using the Bimetal organic framework（Bi-MOF） with solid matrix as precursors, Bi nanospheres are highly dispersed on the Bi@C electrocatalyst that effectively enhances the electrochemical activity. The special morphology of Bi@C electrocatalyst helps the transfer of electrons and ions, significantly reducing the polarization of battery. Herein, the 3D porous carbon frames accelerate mass transfer, and the 2D carbon nanobelts and carbon layer coating on 0D Bi nanospheres improve the conductivity of Bi nanospheres. Therefore, the ICFB with multi-dimensional Bi@C electrocatalyst exhibits coulombic efficiency of 98.10% and energy efficiency of 79.14% at 140 mA cm-2, which is higher than ICFBs with commercial graphite carbon electrocatalyst and with heat treatment carbon felt. This work provides a simple and economical method to fabricate a high-performance multidimensional Bi@C electrocatalyst for Cr3+/Cr2+redox couples, boosting the development of ICFBs.

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Wafer‑Scale Ag_(2)S‑Based Memristive Crossbar Arrays with Ultra‑Low Switching‑Energies Reaching Biological Synapses

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Nano-Micro Letters 2025年第3期17卷 328-339页

作者： Yuan Zhu Tomas Nyberg Leif Nyholm Daniel Primetzhofer Xun Shi Zhen Zhang division of Solid‑State Electronics Department of Electrical EngineeringUppsala University75121 UppsalaSweden Department of Chemistry Uppsala UniversityUppsalaSweden Department of physics and Astronomy Uppsala UniversityUppsalaSweden State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China

Memristive crossbar arrays(MCAs)offer parallel data storage and processing for energy-efficient neuromorphic ***,most wafer-scale MCAs that are compatible with complementary metal-oxide-semiconductor(CMOS)technology still suffer from substantially larger energy consumption than biological synapses,due to the slow kinetics of forming conductive paths inside the memristive *** we report wafer-scale Ag_(2)S-based MCAs realized using CMOS-compatible processes at temperatures below 160℃.Ag_(2)S electrolytes supply highly mobile Ag+ions,and provide the Ag/Ag_(2)S interface with low silver nucleation barrier to form silver filaments at low energy *** further enhancing Ag+migration in Ag_(2)S electrolytes via microstructure modulation,the integrated memristors exhibit a record low threshold of approximately−0.1 V,and demonstrate ultra-low switching-energies reaching femtojoule values as observed in biological *** low-temperature process also enables MCA integration on polyimide substrates for applications in flexible ***,the intrinsic nonidealities of the memristive units for deep learning can be compensated by employing an advanced training *** impressive accuracy of 92.6%in image recognition simulations is demonstrated with the MCAs after the *** demonstrated MCAs provide a promising device option for neuromorphic computing with ultra-high energy-efficiency.

关键词： Wafer-scale Ag_(2)S films Reactive sputter Silver nucleation Ag^(+)migration Energy-efficient neuromorphic computing

Small extracellular vesicles derived from cerebral endothelial cells with elevated microRNA 27a promote ischemic stroke recovery

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Neural Regeneration Research 2025年第1期20卷 224-233页

作者： Yi Zhang Zhongwu Liu Michael Chopp Michael Millman Yanfeng Li Pasquale Cepparulo Amy Kemper Chao Li Li Zhang Zheng Gang Zhang Department of Neurology Henry Ford HospitalDetroitMIUSA Department of physics Oakland UniversityRochesterMIUSA Department of Pathology Henry Ford HospitalDetroitMIUSA division of Pharmacology Department of NeuroscienceReproductive and Dentistry SciencesSchool of MedicineUniversity of Naples“Federico Ⅱ”NaplesItaly

Axonal remodeling is a critical aspect of ischemic brain repair processes and contributes to spontaneous functional *** previous in vitro study demonstrated that exosomes/small extracellular vesicles(sEVs)isolated from cerebral endothelial cells(CEC-sEVs)of ischemic brain promote axonal growth of embryonic cortical neurons and that microRNA 27a(miR-27a)is an elevated miRNA in ischemic *** the present study,we investigated whether normal CEC-sEVs engineered to enrich their levels of miR-27a(27a-sEVs)further enhance axonal growth and improve neurological outcomes after ischemic stroke when compared with treatment with non-engineered CEC-sEVs.27a-sEVs were isolated from the conditioned medium of healthy mouse CECs transfected with a lentiviral miR-27a expression *** EVs isolated from CECs transfected with a scramble vector(Scra-sEVs)were used as a *** male mice were subjected to permanent middle cerebral artery occlusion and then were randomly treated with 27a-sEVs or *** array of behavior assays was used to measure neurological *** with treatment of ischemic stroke with Scra-sEVs,treatment with 27a-sEVs significantly augmented axons and spines in the peri-infarct zone and in the corticospinal tract of the spinal grey matter of the denervated side,and significantly improved neurological *** vitro studies demonstrated that CEC-sEVs carrying reduced miR-27a abolished 27a-sEV-augmented axonal *** analysis revealed that 27a-sEVs systemically administered preferentially localized to the pre-synaptic active zone,while quantitative reverse transcription-polymerase chain reaction and Western Blot analysis showed elevated miR-27a,and reduced axonal inhibitory proteins Semaphorin 6A and Ras Homolog Family Member A in the peri-infarct *** of the Clathrin-dependent endocytosis pathway substantially reduced neuronal internalization of *** data provide evidence that 27a-sEVs have

关键词： axonal remodeling cerebral endothelial cells exosomes miR-27a mitochondria Semaphorin 6A small extracellular vesicles stroke

Sudden change of interferometric power for X-shape states

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Chinese physics B 2025年第02期 136-143页

作者：朱典张福林陈景灵 Theoretical physics division Chern Institute of Mathematics Nankai University Department of physics School of Science Tianjin University

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