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Dipole and generalized oscillator strength derived electronic properties of an endohedral hydrogen atom embedded in a Debye-Huckel plasma

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Matter and radiation at Extremes 2018年第5期3卷 227-242页

作者： C.Martínez-Flores r.cabrera-trujillo Instituto de Ciencias Físicas Universidad Nacional Autonoma de MexicoAp.Postal 43-8CuernavacaMorelos62251Mexico

We report electronic properties of a hydrogen atom encaged by an endohedral cavity under the influence of a weak plasma interaction. Weimplement a finite-difference approach to solve the Schrodinger equation for a hydrogen atom embedded in an endohedral cavity modeled by theWoods-Saxon potential with well depth V0, inner radius r0, thickness D, and smooth parameter g. The plasma interaction is described by aDebye-Hu¨ckel screening potential that characterizes the plasma in terms of a Debye screening length lD. The electronic properties of theendohedral hydrogen atom are reported for selected endohedral cavity well depths, V0, and screening lengths, lD, that emulate differentconfinement and plasma conditions. We find that for low screening lengths, the endohedral cavity potential dominates over the plasma interaction by confining the electron within the cavity. For large screening lengths, a competition between both interactions is observed. We assessand report the photo-ionization cross section, dipole polarizability, mean excitation energy, and electronic stopping cross section as function of lD and V0. We find a decrease of the Generalized Oscillator Strength (GOS) when the final excitation is to an s state as the plasma screeninglength decreases. For a final excitation into a p state, we find an increase in the GOS as the endohedral cavity well-depth increases. For the caseof the electronic stopping cross section, we find that the plasma screening and endohedral cavity effects are larger in the low-to-intermediateprojectile energies for all potential well depths considered. Our results agree well to available theoretical and experimental data and are afirst step towards the understanding of dipole and generalized oscillator strength dependent properties of an atom in extreme conditions encagedby an endohedral cavity immersed in a plasma medium.

关键词： Oscillator strengths Debye-Huckel plasma Cavities Endohedral Energy loss Stopping power

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High pressure effects on the excitation spectra and dipole properties of Li, Be+, and B2+ atoms under confinement

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Matter and radiation at Extremes 2020年第2期5卷 43-52页

作者： C.Martinez-Flores r.cabrera-trujillo Departamento de Qu´ımica Universidad Aut´onoma Metropolitana IztapalapaSan Rafael Atlixco 186Col.VicentinaIztapalapaC.P.09340 M´exico D.F.Mexico Instituto de Ciencias F´ısicas Universidad Nacional Aut´onoma de M´exicoAp.Postal 43-8CuernavacaMorelos62251Mexico Theoretische Chemie Physikalisch-Chemisches InstitutUniversit¨at HeidelbergINF 22969120 HeidelbergGermany

Properties of atoms and molecules undergo significant changes when subjected to spatial *** study the excitation spectra of lithiumlike atoms in the initial 1s22s electronic configuration when confined by an impenetrable spherical *** implement Slater’s X-αmethod in Hartree–Fock theory to obtain the excitation *** that as the cavity size decreases,the total,2s,2p,and higher excited energy levels ***,we confirm the existence of crossing points between ns–np states for low values of the confinement radius such that the ns→np dipole transition becomes zero at that critical *** crossing points of the s–p states imply that instead of photon absorption,one observes photon emission for cavities with radius smaller than the critical ***,the dipole oscillator strength associated with the 2s→2p transition becomes negative,and for higher pressures,the 2s→3p dipole oscillator strength transition becomes larger than *** validate the completeness of the spectrum by calculating the Thomas–reiche–Kuhn sum rule,as well as the static dipole polarizability and mean excitation energy of lithium-like *** find that the static dipole polarizability decreases and exhibits a sudden change at the critical pressure for the absorption-to-emission *** mean excitation energy increases as the pressure ***,as a consequence of the critical transition fromabsorption to emission,themean excitation energy becomes undetermined for higher pressures,with implications formaterial damage under extreme *** unconfined systems,our results show good to excellent agreement with data found in the literature.

关键词： transition. excitation dipole

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Mo_(2)P Monolayer as a Superior Electrocatalyst for Urea Synthesis from Nitrogen and Carbon Dioxide Fixation:A Computational Study

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Energy & Environmental Materials 2024年第1期7卷 207-214页

作者： Dongxu Jiao Zhongxu Wang Yuejie Liu Qinghai Cai Jingxiang Zhao Carlos r.cabrera Zhongfang Chen College of Chemistry and Chemical Engineering and Key Laboratory of Photonic and Electronic Bandgap Materials Ministry of EducationHarbin Normal UniversityHarbin 150025China Modern Experiment Center Harbin Normal UniversityHarbin 150025China Heilongjiang Province Collaborative Innovation Center of Cold region Ecological Safety Harbin 150025China Department of Chemistry and Biochemistry The University of Texas at El PasoEl Paso TX 79968USA Department of Chemistry University of Puerto RicoRio Piedras CampusSan JuanPuerto Rico 00931USA

Urea synthesis through the simultaneous electrocatalytic reduction of N_(2)and CO_(2)molecules under ambient conditions holds great promises as a sustainable alternative to its industrial production,in which the development of stable,highly efficient,and highly selective catalysts to boost the chemisorption,activation,and coupling of inert N_(2)and CO_(2)molecules remains rather ***,by means of density functional theory computations,we proposed a new class of two-dimensional nanomaterials,namely,transition-metal phosphide monolayers(TM_(2)P,TM=Ti,Fe,Zr,Mo,and W),as the potential electrocatalysts for urea *** results showed that these TM_(2)P materials exhibit outstanding stability and excellent metallic ***,the Mo_(2)P monolayer was screened out as the best catalyst for urea synthesis due to its small kinetic energy barrier(0.35 eV)for C-N coupling,low limiting potential(-0.39 V),and significant suppressing effects on the competing side *** outstanding catalytic activity of the Mo_(2)P monolayer can be ascribed to its optimal adsorption strength with the key^(*)NCON species due to its moderate positive charges on the Mo active *** findings not only propose a novel catalyst with high-efficiency and high-selectivity for urea production but also further widen the potential applications of metal phosphides in electrocatalysis.

关键词： C-N coupling density functional theory Mo_(2)P monolayer urea synthesis

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Single-atom catalysts with anionic metal centers: Promising electrocatalysts for the oxygen reduction reaction and beyond

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Journal of Energy Chemistry 2021年第12期30卷 285-293,I0006页

作者： Jinxing Gu Yinghe Zhao Shiru Lin Jingsong Huang Carlos r.cabrera Bobby G.Sumpter Zhongfang Chen Department of Chemistry University of Puerto Rico.Rio Piedras Campus.San Juan.Puerto Rico 00931USA Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTennessee 37831USA Department of Chemistry and Biochemistry The University of Texas at El PasoEl PasoTexas 79968USA

Ongoing efforts to develop single-atom catalysts(SACs) for the oxygen reduction reaction(Orr) typically focus on SACs with cationic metal centers,while SACs with anionic metal centers(anionic SACs) have been generally ***,anionic SACs may offer excellent active sites for Orr,since anionic metal centers could facilitate the activation of O_(2) by back donating electrons to the antibonding orbitals of O_(2).In this work,we propose a simple guideline for designing anionic SACs:the metal centers should have larger electronegativity than the surrounding atoms in the substrate on which the metal atoms are *** means of density functional theory(DFT) simulations,we identified 13 anionic metal centers(Co,Ni,Cu,ru,rh,Pd,Ag,re,Os,Ir,Pt,Au,and Hg) dispersed on pristine or defective antimonene substrates as new anionic SACs,among which anionic Au and Co metal centers exhibit limiting potentials comparable to,or even better than,conventional Pt-based catalysts towards *** also found that anionic Os and re metal centers on the defective antimonene can electrochemically catalyze the nitrogen reduction reaction(Nrr) with a limiting potential close to that of stepped ru(0001).Overall,our work shows promise towards the rational design of anionic SACs and their utility for applications as electrocatalysts for Orr and other important electrochemical reactions.

关键词： Single-atom catalysts Anionic metal centers Antimonene Oxygen reduction reaction Nitrogen reduction reaction

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Coarse to Fine: The role of Severe Plastic Deformation in Advancing Titanium-Based Medical Implants - A Comprehensive review

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 295-306页

作者： Dragana r Mihajlović Bojan I Međo Ivana Lj Cvijović-Alagić Veljko r Djokić Faculty of Technology and Metallurgy University of BelgradeKarnegijeva 411120 BelgradeSerbia Vinča Institute of Nuclear Sci-ences-National Institute of the republic of Serbia University of Belgrade11001BeogradSerbia Innovation Centre of the Faculty of Technology and Metallurgy Karnegijeva 411120 BelgradeSerbia

This paper describes severe plastic deformation(SPD)procedures,which are utilized to form an ultrafine-grained structure in metallic *** the SPD process,a solid material sample is subjected to very high loads without a significant change in sample *** the present work,the high-pressure torsion(HPT)process,as one of the SPD techniques,which achieves a high degree of deformation and ensures refinement of the microstructure,will be discussed in more *** that grain size control is accepted as a method to obtain materials with desired characteristics,an overview of the properties of ultrafine-grained titanium-based biomaterials to be used in medicine is ***,particular attention is dedicated to the influences of HPT process parameters,primarily hydrostatic pressure,and number of revolutions during torsion,on the grain size and physical and mechanical characteristics(modulus of elasticity,microhardness,and tensile properties),corrosion resistance,and biocompatibility of the titanium-based biomaterials.A review of the literature indicates that titanium-based materials obtained by the SPD process show improved mechanical and physical properties without losing biocompatibility and corrosion resistance,which suggests that these methods of obtaining implants are something that should be further developed in the future.

关键词： high-pressure torsion process ultrafine-grained titanium-based materials electrochemical anodization physical properties mechanical properties

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Emerging potential of progranulin-dependent SorCS2 signaling in healthy and diseased nervous systems

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Neural regeneration research 2025年第9期20卷 2591-2593页

作者： Alena Salasova Anders Nykjær Danish research Institute of Translational Neuroscience DANDrITE-Nordic EMBL Partnership for Molecular Medicine and Centre of Excellence PROMEMODepartment of BiomedicineAarhus UniversityAarhusDenmark

The formation of the mammalian nervous system and its maturation into sensory,motor,cognitive,and behavioral circuits is a complex process that begins during early embryogenesis and lasts until young *** neurodevelopm... 详细信息

关键词： progr jointly CS2

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Security Strategy of Digital Medical Contents Based on Blockchain in Generative AI Model

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Computers, Materials & Continua 2025年第1期82卷 259-278页

作者： Hoon Ko Marek r.Ogiela Division of Computer Science and Engineering Sunmoon UniversityAsan31460Republic of Korea AGH University of Krakow Cryptography and Cognitive Informatics LaboratoryKrakow30-059Poland

This study presents an innovative approach to enhancing the security of visual medical data in the generative AI environment through the integration of blockchain *** combining the strengths of blockchain and generative AI,the research team aimed to address the timely challenge of safeguarding visual medical *** participating researchers conducted a comprehensive analysis,examining the vulnerabilities of medical AI services,personal information protection issues,and overall security *** multi faceted exploration led to an indepth evaluation of the model’s performance and ***,the correlation between accuracy,detection rate,and error rate was *** analysis revealed insights into the model’s strengths and limitations,while the consideration of standard deviation shed light on the model’s stability and performance *** study proposed practical improvements,emphasizing the reduction of false negatives to enhance detection rate and leveraging blockchain technology to ensure visual data integrity in medical *** blockchain to generative AI-created medical content addresses key personal information protection *** utilizing the distributed ledger system of blockchain,the research team aimed to protect the privacy and integrity of medical data especially medical *** approach not only enhances security but also enables transparent and tamperproof ***,the use of generative AI models ensures the creation of novel medical content without compromising personal information,further safeguarding patient *** conclusion,this study showcases the potential of blockchain-based solutions in the medical field,particularly in securing sensitive medical data and protecting patient *** proposed approach,combining blockchain and generative AI,offers a promising direction toward more robust and secure medical content *** research and advancements

关键词： Digitalmedical content medical diagnostic visualization security analysis generativeAI blockchain vulnerability pattern recognition

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Ubiquitination and PArylation cross-talk about immunity

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Molecular Plant 2021年第12期14卷 1976-1978页

作者： Marco trujillo Faculty of Biology Cell BiologyⅡUniversity of Freiburg79104 FreiburgGermany

Post-translational modifications(PTMs)allow organisms to quickly respond and acclimate to environmental *** attachment of ubiquitin and its different polymeric forms,act as signals that modulate most aspects of cellular *** is of key importance to maintain protein homeostasis during the immune response by coordinating the major degradation path-ways,namely proteasomal and vacuolar in plants(trujillo,2021).Poly(ADP-ribosyl)ation(PArylation),has also been linked to various stress responses and shows many commonalities to ubiquitination(rissel and Peiter,2019).Yao et al.(2021)have now uncovered a link between these two PTMs.

关键词： maintain translational polymeric

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A comprehensive investigation on nonlinear vibration and bending characteristics of bio-inspired helicoidal laminated composite structures

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 81-100页

作者： S.SAUrABH r.KIrAN D.SINGH r.VAISH V.S.CHAUHAN School of Mechanical and Materials Engineering Indian Institute of Technology Mandi

Bio-inspired helicoidal composite laminates, inspired by the intricate helical structures found in nature, present a promising frontier for enhancing the mechanical properties of structural designs. Hence, this study provides a comprehensive investigation into the nonlinear free vibration and nonlinear bending behavior of bio-inspired composite plates. The inverse hyperbolic shear deformation theory(IHSDT) of plates is employed to characterize the displacement field, with the incorporation of Green-Lagrange nonlinearity. The problem is modeled using the C0finite element method(FEM), and an in-house code is developed in the MATLAB environment to solve it numerically. Various helicoidal layup configurations including helicoidal recursive(Hr), helicoidal exponential(HE), helicoidal semi-circular(HS), linear helicoidal(LH), and Fibonacci helicoidal(FH)with different layup sequences and quasi-isotropic configurations are studied. The model is validated, and parametric studies are conducted. These studies investigate the effects of layup configurations, side-to-thickness ratio, modulus ratios, boundary conditions, and loading conditions at different load amplitudes on the nonlinear vibration and nonlinear bending behaviors of bio-inspired composite plates. The results show that the laminate sequence exerts a substantial impact on both nonlinear natural frequencies and nonlinear bending behaviors. Moreover, this influence varies across different side-to-thickness ratios and boundary conditions of the bio-inspired composite plate.

关键词： Inverse problems

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Machine Learning Techniques in Predicting Hot Deformation Behavior of Metallic Materials

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 713-732页

作者： Petr Opela Josef Walek Jaromír Kopecek Department of Metallurgical Technologies Faculty of Materials Science and TechnologyVSB–Technical University of OstravaOstrava70800Czech Republic FZU—Institute of Physics of the Czech Academy of Sciences Prague18200Czech Republic

In engineering practice,it is often necessary to determine functional relationships between dependent and independent *** relationships can be highly nonlinear,and classical regression approaches cannot always provide sufficiently reliable ***,Machine Learning(ML)techniques,which offer advanced regression tools to address complicated engineering issues,have been developed and widely *** study investigates the selected ML techniques to evaluate their suitability for application in the hot deformation behavior of metallic *** ML-based regression methods of Artificial Neural Networks(ANNs),Support Vector Machine(SVM),Decision Tree regression(DTr),and Gaussian Process regression(GPr)are applied to mathematically describe hot flow stress curve datasets acquired experimentally for a medium-carbon *** the GPr method has not been used for such a regression task before,the results showed that its performance is the most favorable and practically unrivaled;neither the ANN method nor the other studied ML techniques provide such precise results of the solved regression analysis.

关键词： Machine learning Gaussian process regression artificial neural networks support vector machine hot deformation behavior

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