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influence of cerium ions on structure-dependent magnetic properties of Ba-Sr m-type hexaferrite nanocrystals

Journal of Rare Earths 2024年第2期42卷 364-372,I0005页

作者： ram A.Pawar Sunil m.Patange P.m.Dighe Sher Singh meena Abdullah GAl-Sehemi mehboobali Pannipara Santosh S.Jadhav Department of Physics ArtsCommerce and Science CollegeAhmednagar413711MaharashtraIndia Department of Physics Shri Krishna MahavidyalayaGunjotiDistOsmanabad413606MaharashtraIndia Padmashri Vikhe Patil College of Arts Science and CommercePravaranagarA/P.Loni(Kd)Tal.RahataDistAhmednagar413713MaharashtraIndia Solid State Physics Division Bhabha Atomic Research CentreMumbai400085MaharashtraIndia Department of Chemistry King Khalid UniversityAbha61413Saudi Arabia Department of Physics D.S.M's ArtsCommerce and Science CollegeJintur431509MaharashtraIndia

The present study is a systematic effort to investigate the structure-sensitive magnetic parameters of Ce^(3+) substituted Ba-Sr hexaferrite nanocrystals chemically formulated as Ba_(0.5)Sr_(0.5)Ce_(x)Fe_(12-x)O_(19) where x=0.0-0.2 with Δx=*** hexaferrite powders were prepared using the sol-gel self-ignition route and structurally characterized by means of powder X-ray diffraction and Fourier transform infrared *** creation of the m-type hexaferrite phase within the synthesized samples was revealed from the Rietveld refinement of the X-ray *** occurrence of a secondary phase of CeO_(2) was revealed within the hexaferrites for the substitution,x> *** refined X-ray diffraction data were utilized to compute the lattice parameters,X-ray density,and lattice parameter *** crystal structure plotted from the refined XRD data reveals the occupancy of the ions at different lattice *** XPS data of the hexaferrite were analyzed to confirm the oxidation states of the constituent *** nanocrystalline nature of the hexaferrites was revealed from the crystallite sizes calculated using Scherer's *** analysis of FTiR spectra confirms that only a fraction of Ce^(3+)accommodated in the lattice and the remaining Ce content reside in the form of the CeO_(2) *** morphology of the hexaferrites was analyzed from the FESEm profiles of the ferrite *** magnetic behavior study was performed by analyzing the Curie temperature,hysteresis loops,and hyperfine interactions by means of susceptibility,V.S.m,and mossbauer spectroscopy,*** hexaferrites with increasing coercivity,decreasing saturation magnetization,and decreasing Curie temperature are reported in the *** substituted Ce^(3+)ions inhibit the grain growth and create lattice imperfections giving rise to hexaferrites with tuned magnetic parameters suitable for different applications.

关键词： Ba-Sr hexaferrite Ce^(3+)substitution XPS Saturation magnetization Coercivity m?ssbauer spectroscopy

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HVSR analysis of pumice sands for sediment depth characterization:A case study for Guadalajara,mexico

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Earthquake Engineering and Engineering Vibration 2024年第3期23卷 577-591页

作者： Hafid Salgado m. alejandro ramírez-Gaytan Adolfo Preciado Christian R.Escudero Departamento de Ciencias Exactas Centro Universitario de la CostaUniversidad de GuadalajaraCP.48280 Puerto VallartaJaliscoMéxico Departamento de Ciencias Computacionales Centro Universitario de Ciencias Exactas e IngenieríaUniversidad de GuadalajaraCP.44430 GuadalajaraJaliscoMéxico Departamento del Hábitat y Desarrollo Urbano Instituto Tecnológico y de Estudios Superiores de Occidente(ITESO)CP.45604 TlaquepaqueMéxico

The horizontal to vertical spectral ratio(HVSR)methodology is used here to characterize pumice soils and to image the three-dimensional surface geometry of Guadalajara,*** to other Latin American cities,Guadalajara is exposed to high seismic risk,with the particularity of being the largest urban settlement in Latin America built on pumice *** has not yet been tested to characterize subsoil depths in pumice *** to the questionable use of traditional geotechnical tests for the analysis of pumice soils,HVSR provides an alternative for its characterization without altering its fragile and porous *** this work,resonance frequency(F0)and peak amplitude(A0)are used to constrain the depth of the major impedance contrast that represents the interface between bedrock and pumice *** were compared with borehole depths and other available geotechnical and geophysical data and show good *** of the profiles estimated on the riverbanks that cross the city,reveals different subsoil thickness that could have an impact on different site responses on riverine areas to an eventual *** and academic efforts are combined in this work to characterize depth sediments,an important parameter that impacts the regulations for construction in the city.

关键词： subsoil of Guadalajara shallow soil thickness bedrock depth pumice soil characterization

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Solution of the Center Problem for a Class of Polynomial Differential Systems

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Acta mathematica Sinica,English Series 2024年第7期40卷 1685-1696页

作者： Chang Jian Liu Jaume Llibre Rafael ramírez Valentín ramírez School of mathematics(Zhuhai) Sun Yat-sen UniversityZhuhai519086P.R.China Departament de matemàtiques Universitat Autònoma de Barcelona08193BellaterraBarcelonaCataloniaSpain Departament d’Enginyeria informàtica i matemàtiques Universitat Rovira i VirgiliAvinguda dels Paiïsos Catalans 2643007TarragonaCataloniaSpain

Consider the polynomial differential system of degree m of the form x=-y(1+μ(a_(2)x-a_(1)y))+x(v(a_(1)x+a_(2)y)+Ω_(m-1)(x,y)),y=x(1+μ(a_(2)x-a_(1)y))+y(v(a_(1)x+a_(2)y)+Ω_(m-1)(x,y)),whereμandνare real numbers such that(μ^(2)+v^(2))(μ+v(m-2))(a_(1)^(2)+a_(2)^(2))≠m>2 andΩ_(m−1)(x,y)is a homogenous polynomial of degree m−1.A conjecture,stated in *** Equations 2019,suggests that whenν=1,this differential system has a weak center at the origin if and only if after a convenient linear change of variable(x,y)→(X,Y)the system is invariant under the transformation(X,Y,t)→(−X,Y,−t).For every degree m we prove the extension of this conjecture to any value ofνexcept for a finite set of values ofμ.

关键词： Center problem polynomial differential system

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Seedling potential of trees species along the elevational gradient in temperate hill forest of central Nepal

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Journal of mountain Science 2024年第4期21卷 1329-1344页

作者： DANi ram Sharan BANiYA Chitra Bahadur Central Department of Botany Tribhuvan UniversityKirtipur 44618Nepal

Regeneration status of tree species along elevation gradient in temperate hill forest was not understood *** research examined the tree diversity and its regeneration patterns along an elevation gradient in temperate hill forest,central *** were collected from 300 sample plots within vertical elevation bands of 10,ranging from 1365 to 2450 m asl.A random sampling method was used for data collection in three seasons,winter,pre-monsoon and post monsoon *** at breast height(DBH)was used to broadly categorize the plant individual into trees,saplings and *** tree species richness ranged from 12 to 25 with density of 350 to 1200 individuals per *** richness of tree and sapling showed statistically significant unimodal pattern,which peaked at *** showed a strong and positive linear correlation with the seedling density(Deviance=0.99,pignificant hump-shaped relationship with sapling density(Deviance=0.95,pimilarly,elevations showed a statistically significant negative hump-shaped relationship with all trees,saplings and seedling stages(Deviances=0.89,0.87 and 0.57).The highest values of the Shannon-Wiener index and the lowest value of the Simpson index were found at mid-elevation for all growth *** 92%of tree species were found at regenerating stage;49%in a good renewal regeneration status,32%in fair renewal regeneration,and 11%at a poor regenerating ***,4%of tree species were reported as non-regenerating stages and 4%were newly introduced ***,the regeneration status of the study area was considered fairly well since sapling(78.5%)>seedling(10.6%)≤mature(10.9%).Among tested environmental variables,elevation and annual mean rainfall were the most influential factors in the regeneration of tree species.

关键词： Regeneration potential Chandragiri hill Altitudinal gradient Species diversity Tree species richness

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From prediction to prevention:machine learning revolutionizes hepatocellular carcinoma recurrence monitoring

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World Journal of Gastroenterology 2024年第7期30卷 631-635页

作者： mariana michelle ramírez-mejía Nahum méndez-Sánchez Plan of Combined Studies in medicine Faculty of MedicineNational Autonomous University of MexicoDistrito Federal 04510Mexico Liver Research Unit Medica Sur Clinic&FoundationDistrito Federal 14050Mexico Faculty of medicine National Autonomous University of MexicoDistrito Federal 04510Mexico

in this editorial,we comment on the article by Zhang et al entitled Development of a machine learning-based model for predicting the risk of early postoperative recurrence of hepatocellular *** carcinoma(HCC),which is characterized by high incidence and mortality rates,remains a major global health challenge primarily due to the critical issue of postoperative *** recurrence,defined as recurrence that occurs within 2 years posttreatment,is linked to the hidden spread of the primary tumor and significantly impacts patient *** predictive factors,including both patient-and treatment-related factors,have limited predictive ability with respect to HCC *** integration of machine learning algorithms is fueled by the exponential growth of computational power and has revolutionized HCC *** study by Zhang et al demonstrated the use of a groundbreaking preoperative prediction model for early postoperative HCC *** persist,including sample size constraints,issues with handling data,and the need for further validation and *** study emphasizes the need for collaborative efforts,multicenter studies and comparative analyses to validate and refine the *** these challenges and exploring innovative approaches,such as multi-omics integration,will enhance personalized oncology *** study marks a significant stride toward precise,efficient,and personalized oncology practices,thus offering hope for improved patient outcomes in the field of HCC treatment.

关键词： Hepatocellular carcinoma Early recurrence machine learning XGBoost model Predictive precision medicine Clinical utility Personalized interventions

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Enhancement of coercivity,permeability,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites for memory and high frequency devices

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Journal of Rare Earths 2024年第6期42卷 1128-1135,I0005页

作者： i.Sardar m.D.Hossain m.S.Sikder m.N.i.Khan m.R.Rahman Physics Discipline Khulna UniversityKhulna9208Bangladesh Department of Physics Khulna University of Engineering&TechnologyKhulna9203Bangladesh Department ofComputer Science and Engineering Northern University of Business&Technology KhulnaKhulna9100Bangladesh material Science Division Atomic Energy CentreDhaka1000Bangladesh

Spinel cubic ferrites have huge applications in me mory and high frequency *** the improvement of these modern devices,the magnetic coercivity,permeability,and dielectric properties of a ferrite are the important *** article focuses on improving the magnetic coercivity,magnetic permeability,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites,where x=0.00,0.06,and *** X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTiR),field emission scanning electron microscopy(FESEm),energy dispersive X-ray(EDX),vibrating sample magnetometer(VSm),and an impedance analyzer were used to characterize the structural,magnetic,and dielectric properties of the *** XRD patterns indicate the formation of spinel cubic structure of the samples with a secondary peak(EuFeO_(3))for Eu doped *** densities and porosities of the samples follow an inverse trend,where the doped samples’lattice parameters are increased with the increment of rare earth Eu *** FTiR analysis also proves the spinel cubic phase of the *** average grain size of the ferrites is obtained via FESEm images,and it is increased from 121 to 198 *** analysis confirms that doping of the Eu content also changes other hysteresis loop properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ***,the coercivity of the Eu doped samples is greater than that of the mother alloy(x=0.00).The EDX study shows that there is no impurity contamination in the *** permeability and dielectric measurements show an improved quality factor of the Eu-doped samples with low magnetic and dielectric *** dependent resistivity and impedance analysis also show the improved *** the observed properties of the samples,all the investigated ferrites might be strong candidates for potential applications in memory devices,magnetic sensors,and high frequency applications.

关键词： Ferrites Raree arths Coercivity Permeability EDX Resistivity

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An investigation into Forced Convection of a Nanofluid Flowing in a Rectangular microchannel under the influence of a magnetic Field

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Fluid Dynamics & materials Processing 2024年第2期20卷 311-323页

作者： muataz S.Alhassan Ameer A.Alameri Andrés Alexis ramírez-Coronel i.B.Sapaev Azher m.Abed David-Juan ramos-Huallpartupa Rahman S.Zabibah Division of Advanced Nanomaterial Technologies Scientific Research CenterAl-Ayen UniversityThi-QarIraq Department of Chemistry College of ScienceUniversity of BabylonBabylonIraq Research Group in Educational Statistics National University of EducatiosnAzoguesEcuador Department Physics and Chemistry Tashkent Institute of Irrigation and Agricultural Mechanization EngineersNational Research UniversityTashkentUzbekistan Akfa University TashkentUzbekistan New Uzbekistan University TashkentUzbekistan Department of Airconditioning and Refrigeration Engineering Al-Mustaqbal University CollegeHilla51001Iraq Academic Department of Agro-industrial Engineering and Technology Universidad Nacional JoséMaría ArguedasApurimacPerú The islamic University NajafIraq

in line with recent studies,where it has been shown that nanoﬂuids containing graphene have a stronger capacity to boost the heat transfer coefﬁcient with respect to ordinary nanoﬂuids,experiments have been conducted using water with cobalt ferrite/graphene *** particular,a circular channel made of copper subjected to a constant heatﬂux has been *** nanoparticles are sensitive to the presence of a magneticﬁeld,different conditions have been examined,allowing both the strength and the frequency of such aﬁeld to span relatively wide ranges and assuming different concentrations of *** to theﬁndings,the addition of nanoparticles to theﬂuid causes its rotation speed to increase by a factor of two,whereas ultraviolet radiation plays a negligible *** amount of time required to attain the maximum rotation speed of the nanoﬂuid and the Nusselt number have been measured under both constant and alternating magneticﬁelds for a ferroﬂuid with a concentration of 0.5%and atﬂow Reynolds number of 550 and 1750.

关键词： Nano fluid rectengular tube magnetic field

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Smart tailoring of molecular catalysts:mounting approach to oxygen reduction reaction

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Journal of materials Science & Technology 2024年第1期168卷 169-184页

作者： Anuj Kumar mohd Ubaidullah Guoxin Zhang Jasvinder Kaur Saira Ajmal mudassir Hasan Krishna Kumar Yadav Hafiz m.Adeel Sharif ram K.Gupta Ghulam Yasin Nano-Technology Research Laboratory Department of ChemistryGLA UniversityMathuraUttar Pradesh 281406India Department of Chemistry College of ScienceKing Saud UniversityRiyadh 11451Saudi Arabia Department of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdaoShandong 266590China institute for Advanced Study Shenzhen UniversityShenzhenGuangdong 518060China Department of Chemistry Kansas Polymer Research CenterPittsburg State UniversityPittsburgKS 66762United States Faculty of Science and Technology Madhyanchal Professional UniversityRatibadBhopal 462044India Environmental and Atmospheric Sciences Research Group Scientific Research CenterAl-Ayen UniversityThi-QarNasiriyah 64001Iraq Department of Chemical Engineering King Khalid University Saudi Arabia Department of Chemistry School of SciencesIFTM UniversityMoradabadUttar Pradesh 244102India Research Center for Eco-Environmental Engineering Dongguan University of TechnologyDongguan 523808China School of Environment and Civil Engineering Dongguan University of TechnologyDongguanGuangdong 523808China

Efficient electrocatalytic rupture of energy-rich molecules(H_(2)and O_(2))is a green approach for gener-ating clean energy for modern *** this context,porphyry-type molecular electrocatalysts act intelligently toward oxygen reduction reaction(ORR),a fundamental process in fuel cells,due to their redox-rich chemistry,which involves core metal ions and macrocyclic *** concerned scientific community has tried many times to correlate the ORR intermediates with their formation kinetics and simplify the associated multi H+/e-stages during the ORR process,constructing several volcano plots be-tween catalytic Tafel data,turnover frequencies,and overpotentials for many *** the fact that many review articles on molecular electrocatalysts for ORR have been published,understanding the strategic implications and molecular catalyst intelligence towards homogenous ORR has been poorly *** review examined the relationships between volcano plots of current *** parameters and the Sabatier principle in order to explain the intelligence of molecular electrocatalysts and approaches for their creation,as well as the difficulties and potential prospects of molecular *** facts distinguish this review from previously published articles and will pique the scien-tific community’s interest in avoiding trial-and-error procedures for catalyst creation while also allowing for more exact evaluations of the molecular catalyst’s performance.

关键词： Electrocatalysis molecular catalysts Oxygen reduction reaction Sabatier principle

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Effectiveness of external prestressing in enhancing the non-ductile hanger failure mechanism in reinforced concrete inverted T-beams

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 1050-1065页

作者： Ahmed m.ATTA Reda N.BEHiRY mohammed i.HARAZ Structural Engineering Department Faculty of EngineeringTanta UniversityTanta 33511Egypt Nile Higher institute for Engineering and Technology Mansoura 11001Egypt

Recently,inverted T-beams have been used in reinforced concrete(RC)bridges to support transverse precast *** T-beams,contrary to practice with conventional beams,are loaded on the flanges upper *** loading configuration causes hanger failure due to the generation of vertical tensile stresses near the bottom of the *** key purpose of this study is to investigate the efficiency of vertical external prestressing stainless-steel bars in mitigating non-ductile hanger failure in reinforced concrete inverted *** experimental study on six inverted-T beams,including two un-strengthened specimens,was carried *** study showed that the value of the prestressing level had a considerable impact on the performance of hanger mechanism in relation to crack pattern,ultimate loads,cracking behavior,load-deflection,strains,and *** experimental results indicated that the suggested method for strengthening inverted T-beams had efficacy in reducing the seriousness of the non-ductile hanger failure and resulted in a strength increase of up to 53% when compared to that of the un-strengthened ***,two analytical models for estimating the hanger capacity and the average crack width of the strengthened RC inverted T-beams were *** models that were proposed exhibited a high degree of agreement with the experimental results.

关键词： RC bridges inverted T-beams strengthening hanger failure external prestressing

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Developing a two-decadal time-record of rice field maps using Landsat-derived multi-index image collections with a random forest classifier:A Google Earth Engine based approach

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information Processing in Agriculture 2024年第2期11卷 260-275页

作者： W.Ashane m.Fernando i.P.Senanayake Department of Nano Science Technology Wayamba University of Sri LankaKuliyapitiya 60200Sri Lanka Dchoolf Engineing CllegeoEngineeringSience and EnionmentThe UniversyewcastleCallaghanW2Austraia

Historic maps showing the temporal distribution of rice fields are important for precision agriculture,irrigation optimisation,forecasting crop yields,land use management and formulating ***,mapping rice felds using traditional ground surveys is impractical when high cost,time and labour requirements are considered,and the availability of such detailed records is *** satellite remote sensing appears to be a viable solution,conventional segmentation and classification methods with spectral bands are often unable to contrast the distinct characteristics between rice fields and other vegetation *** this end,we explored a novel,Google Earth Engine(GEE)based multiindex random forest(RF)classification approach to map rice fields over two *** images from 2000 to 2020 of two Sri Lankan rice cultivation districts were extracted from GEE and a multi-index RF classification algorithm was applied to distinguish the rice *** results showed above 80%accuracy for both training and validation,when compared against high spatial resolution Google Earth *** essence,multi-index sampling and RF together synergised the compelling classifcation accuracy by effectively capturing vegetation,water(ponding)and soil characteristics unique to the rice felds using a single-click *** maps developed in this study were further compared against the mODiS land cover type product(mCD12Q1)and the corresponding superior statistics on rice fields demonstrated the robustness of the proposed *** work seeking effective index combinations is recommended,and this approach can potentially be extended to other crop analyses elsewhere.

关键词： Google Earth Engine(GEE) image classification Random forest mapping rice fields Time series analysis Vegetation index

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