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Facile synthesis of samarium and cerium doped double perovskite cobaltite with enhanced dielectric response

Journal of Rare Earths 2024年第7期42卷 1317-1327,I0005页

作者： Yasir Abbas m.Kamran m.Anis-ur-Rehman Applied Thermal Physics Laboratory Department of PhysicsCOMSATS University IslamabadIslamabad 45550Pakistan

The investigation of Sm-Ce doping on structure,conduction,and dielectric response of Bi_(2)Ca_(2-2x)Sm_(x)CexCoo_(6)(x=0.000,0.025,0.050,0.075)(BCSCCo)are *** the specimens were synthesized by a facile synthesis technique named the co-precipitation route.X-ray diffraction(XRD)reveals that BCSCCo crystallizes into one phase with space group P21/*** crystallite size,dislocation density,lattice parameters,lattice strain,unit cell volume,and bulk density were determined using XRD *** structural properties of Bi_(2)Ca_(2)Coo_(6)were examined using calculations based on the density functional *** and experimental values discrepancy is less than 1%.A scanning electron microscope was used for performing a microstructural *** SEm images demonstrate the homogeneous distribution of grains with a range of sizes(0.054-0.090μm).The alternating current(ac)conductivity,dielectric permittivity,and tangent loss were also studied as a function of frequency(20 Hz-3 mHz)at different temperatures(100-500℃).All synthesized samples were examined using non-linear Debye's function to determine their spreading factor and relaxation *** specimen with the lowest crystallite size(∼23 nm)exhibits a high dielectric permittivity(∼3.80×10^(6)).The conduction mechanism was examined in the studied samples with the use of Jonscher's power *** power law indicates that the BCSCCo(x=0.000,0.025)follows correlated barrier hopping,whereas the x=0.050 and 0.075 compositions follow non-overlapping polaron *** studied specimen Bi_(2)Ca_(1.9)0Sm_(0.05)0Ce_(0.05)_(0)Coo_(6)with the highest density(∼5.65 g/cm^(3))displays a high electrical conductivity(∼46.1 S/cm).These findings correspond to those published for ceramics made from calcium cobaltite using solid-state reactions(5.0-26.0 S/cm).

关键词： Bismuth calcium samarium cerium cobaltite (BCSCCo) Spreading factor Conduction mechanism Rare earths

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Polyelectrolyte Complexes between Hyperbranched and Linear Polysaccharides: Fucoidan/Chitosan

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Chinese Journal of Polymer Science 2024年第4期42卷 468-479页

作者： Ekaterina R.Gasilova Daria N.Poshina Aleksandra o.Sitnikova Natalia N.Saprykina Yury A.Skorik Institute of macromolecular Compounds of the Russian Academy of Sciences Bolshoi VO 31St.Petersburg199004Russian Federation

Polyelectrolyte complexes(PECs)of hyperbranched(HB)and linear polysaccharides are promising as more effective encapsulation agents compared to PECs formed by linear *** investigated the PECs between the HB anionic polysaccharide fucoidan(FUC)and the cationic linear polysaccharide chitosan(CS).The FUC had a molecular weight(mW)of 30×*** PECs were prepared in three solvents(water,0.01 and 0.1 mol/L acetic acid)with CS of mW of 15,110 and 170 kDa,and deacetylation degrees(DDA)of 70%and 97%.The structures of the PECs and the initial FUC were investigated by multi-angle static and dynamic light *** the FUC contained 18 wt%of—oSo3 groups and 5 wt%of uronic acid units,it was a“strong-weak”copolyanion,so the HB macromolecules of the FUC formed nanogel particles in 0.1 mol/L AcoH and open branched structures in water,as confirmed by the Kratky *** mixing the solutions of original components,the PEC structures underwent an equilibration period,the duration of which increased with the mW of *** the charge stoichiometry was approached,the PECs shrank;the fractal dimension approached unity,indicating the side-by-side packing of adjacent FUC branches with the help of *** aggregation in the vicinity of the charge compensation was hardly observed,as it occurred in a very narrow *** PEC content at theζ-potential inversion depended on solvents’pH and the DDA of *** the extreme case of core-shell PECs in 0.1 mol/L AcoH,obtained by mixing FUC nanogels with the solutions of high mW CS of 97%DDA,the protruding tails of CS formed a positively charged shell in the whole range of FUC content(10 wt%on microscopy and atomic force microscopy images of dried samples were discussed in relation to the light scattering results.

关键词： Polyelectrolyte complexes Chitosan Hyperbranched fucoidan Light scattering

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Space Rocks-and Dust-Roll into Planetary Science Limelight

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Engineering 2024年第8期39卷 3-6页

作者： Sean o’Neill Senior Technology Writer

Space sample retrieval is having a *** 24 September 2023,in a triumph of complex engineering,a US National Aeronau-tics and Space Administration(NASA)mission,oSIRUS-REx(short for origins,spectral interpretation,resource identification,and security-regolith explorer;regolith is the surface layer of uncon-solidated rocks and dust/soil covering bedrock),successfully deliv-ered to Earth a capsule containing the largest sample of asteroid material ever collected,captured from Bennu.

关键词： rock Earth origin

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Braneworld black holes with modmax electrodynamics on the brane

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Communications in Theoretical Physics 2024年第6期76卷 120-128页

作者： Haryanto m Siahaan Jurusan Fisika Universitas Katolik ParahyanganJalan Ciumbuleuit 94Bandung 40141Indonesia

In this study,we investigate modmax electrodynamics localized within the Randall-Sundrum Ⅱ and Dvali-Gabadadze-Porrati branes,deriving corresponding 3-brane spacetime solutions that conform to the effective Einstein equations in each specific *** construct solutions for charged black holes within the effective Einstein equation framework in both braneworld *** examination explores the trajectories of charged objects in this spacetime,underscoring the significance of the nonlinear *** analysis uncovers the fact that,similar to the prior modmax black hole investigation,the nonlinear parameter plays a pivotal role in suppressing the effective charge of the black hole,due to its definite positive value.

关键词： RS-II DGP modmax brane

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Higgs-like(pseudo)scalars in AdS_(4),marginal and irrelevant deformations in CFT_(3),and instantons on S^(3)

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Chinese Physics C 2024年第4期48卷 68-81页

作者： m.Naghdi Department of Physics Faculty of Basic SciencesUniversity of IlamIlamIran

Employing a 4-form ansatz of 11-dimensional supergravity over a non-dynamical AdS_(4)×S^(7)/Z_(k)background and setting the internal space as an S1 Hopf fibration on CP3,we obtain a consistent ***(pseudo)scalars,in the resulting scalar equations in Euclidean AdS_(4)space,may be considered to arise from(anti)m-branes wrapping around the internal directions in the(Wick-rotated)skew-whiffed m2-brane background(as the resulting theory is for anti-m2-branes),thus realizing the modes after swapping the three fundamental representations 8_(s),8_(c),and 8_(v) of So(8).Taking the backreaction on the external and internal spaces,we obtain the massless and massive modes,corresponding to exactly marginal and marginally irrelevant deformations on the boundary CFT3,***,we obtain a closed solution for the bulk equation and compute its correction with respect to the background ***,considering the Higgs-like(breathing)mode m^(2)=18,having all supersymmetries as well as parity and scale-invariance broken,solving the associated bulk equation with mathematical methods,specifically the Adomian decomposition method,and analyzing the behavior near the boundary of the solutions,we realize the boundary duals in the SU(4)×U(1)-singlet sectors of the ABJm ***,introducing the new dual deformationΔ_(+)=3,6 operators made of bi-fundamental scalars,fermions,and U(1)gauge fields,we obtain the So(4)-invariant solutions as small instantons on a three-sphere with the radius at infinity,which correspond to collapsing bulk bubbles leading to big-crunch singularities.

关键词： AdS_(4)/CFT_(3)correspondence scalar equations in AdS_(4) instantons marginal and irrelevant operators (anti)m-branes

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A hybrid solar-biogas system for post-CoVID-19 rural energy access

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CLEAN ENERGY 2024年第1期8卷 84-99页

作者： overen, ochuko K. obileke, Kechrist meyer, Edson L. makaka, Golden Apeh, oliver o. Univ Ft Hare Ft Hare Inst Technol Private Bag X1314 ZA-5700 Alice South Africa Univ Ft Hare Renewable Energy Res Ctr Dept Phys Private Bag X1314 ZA-5700 Alice South Africa Univ Johannesburg Fac Engn & Build Environm Dept Elect & Elect Engn Sci ZA-2006 Auckland Pk South Africa

Solar home systems for rural electrification are often designed with a limited energy supply, which presents a drawback for the technology. Furthermore, uncontrolled livestock faeces in rural communities constitute environmental sanitation and health risks. Livestock excrement can be used through a biogas digester to supplement solar energy to provide adequate and sustainable electricity access to underserved rural communities while achieving waste management. Therefore, this study presents a hybrid solar-biogas system for a more dynamic energy supply and waste management for post-Covid recovery plans in rural communities. A parametric research approach that involves the use of the Integrated Environment Solution Virtual Environment software application and mathematical models to design the desired household load and the hybrid system sizing is used in the study. The findings show that the daily household energy consumption was 6.6 kWh, equivalent to 206.40 kWh/month. A 1.2-kWp and 1.2-m3 hybrid solar-biogas system was found to adequately power the house. Financially, the total initial investment cost of the system was $5777.20 with a net present value of $6566.78, net profit of $4443.6, a payback period of 14 years and 8 months, and a levelized cost of energy of $0.21/kWh; these include a 60% initial investment and maintenance costs subsidy. Energy performance contracting and energy-as-a-service were recommended to effectively run and operate the system. The study successfully revealed the design, specifications and upscaling mechanism of the proposed hybrid solar-biogas system. more research is required to unveil the efficacy of the system, the performance gap and the perception of the technology by the beneficiaries. A hybrid solar-biogas system is designed for a more dynamic energy supply and waste management for post-Covid recovery plans in rural communities. A parametric research approach is used to specify the desired household load and the hybrid system sizi

关键词： energy access sustainable rural development clean energy waste management post-CoVID-19 recovery plan SoUTH-AFRICA ELECTRIFICATIoN BATCH

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Polyoxidovanadates a new therapeutic alternative for neurodegenerative and aging diseases

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Neural Regeneration Research 2024年第3期19卷 571-577页

作者： Sonia Irais Gonzalez-Cano Gonzalo Flores Jorge Guevara Julio Cesar morales-medina Samuel Treviño Alfonso Diaz Faculty of Chemical Sciences Benemerita Autonomous University of PueblaPueblaMexico Institute of Physiology Benemerita Autonomous University of PueblaPueblaMexico Department of Biochemistry Faculty of MedicineNational Autonomous University of MexicoMexico CityMexico Animal Reproduction Research Center CINVESTAV-Autonomous University of TlaxcalaTlaxcalaMexico

Aging is a natural phenomenon characterized by a progressive decline in physiological integrity,leading to a deterioration of cognitive function and increasing the risk of suffering from chronic-degenerative diseases,including cardiovascular diseases,osteoporosis,cancer,diabetes,and *** is considered the major risk factor for Parkinson’s and Alzheimer’s disease ***,diabetes and insulin resistance constitute additional risk factors for developing neurodegenerative ***,no treatment can effectively reverse these neurodegenerative ***,some antidiabetic drugs have opened the possibility of being used against neurodegenerative *** the previous framework,Vanadium species have demonstrated a notable antidiabetic *** research group evaluated polyoxidovanadates such as decavanadate and metforminium-decavanadate with preventive and corrective activity on neurodegeneration in brain-specific areas from rats with metabolic *** results suggest that these polyoxidovanadates induce neuronal and cognitive restoration *** review aims to describe the therapeutic potential of polyoxidovanadates as insulin-enhancer agents in the brain,constituting a therapeutic alternative for aging and neurodegenerative diseases.

关键词： Alzheimer’s disease antidiabetic brain cognition diabetes insulin neurodegeneration neuroinflammation oxidative stress Vanadium species

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Influence of erbium on structural,and charged particles,photons,and neutrons shielding properties of Ba_(1-x)Er_(x)Sno_(3) perovskite ceramics

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Journal of Rare Earths 2024年第4期42卷 724-732页

作者： m.K.h.Hamad Nidal Dwaikat m.H.A.mhareb m.I.Sayyed R.m.Hamad Y.S.m.Alajerami m.A.Almessiere Gameel Saleh Ahmad Hussein Alomari K.A.Ziq Department of Basic Sciences School of Social and Basics SciencesAl Hussein Technical UniversityKing Abdullah II St 242Amman11831Jordan Department of Physics College of Engineering and PhysicsInterdisciplinary Research Center for Advanced MaterialsKing Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Department of Physics College of ScienceImam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam31441Saudi Arabia Basic and Applied Scientific Research Center Imam Abdulrahman Bin Faisal UniversityP0.Box 1982Dammam31441Saudi Arabia Department of Physics Faculty of ScienceIsra UniversityAmman11622Jordan Department of Nuclear medicine Research Institute for Research and Medical Consultations(IRMC)Imam Abdulrahman Bin Faisal UniversityPo.Box 1982Dammam31441Saudi Arabia medical Imaging Department Applied Medical Sciences FacultyAl Azhar University-Gaza CityPo.Box 1277Palestine Department of Biophysics Institute for Research and Medical Consultations(IRMC)Imam Abdulrahman Bin Faisal UniversityPo.Box1982Dammam 31441Saudi Arabia Department of Biomedical Engineering College of EngineeringImam Abdulrahman Bin Faisal UniversityPo.Box 1982Dammam31441Saudi Energy&minerals Regulatory Commission Amman11821Jordan

Five perovskite ceramics samples of Ba_(1-x)Er_(x)Sno_(3) with x=0.00,0.05,0.10,0.15,and 0.20 were synthesized using the conventional solid-state reaction *** prepared samples were characterized by X-ray diffraction(XRD),Fourier transforms infrared(FTIR),and UV-Vis *** shielding properties against ionizing radiation were also *** XRD analysis shows the perovskite cubic structure as the major phase in all *** FTIR reveals a distinctive band around 614-620 cm^(-1) ascribed to the antisymmetric o-Sn-o ***-Vis spectroscopy was used to determine the bandgap according to diffuse reflectance,and the results display a fixed enhancement in the bandgap from 3.2 to 3.3 eV for all ***-ray shielding properties of the synthesized samples were experimentally measured and compared with XCom computational *** relative differences(Δ,%)between experimental and theo retical values are low and fall within the 0.446%-7.10%*** addition of Er leads to the enhanced density,neutron,and gamma shielding *** contrast,charged particles’shielding parameters gradually reduce with rising Er *** results suggest that Ba_(1-x)Er_(x)Sno_(3) samples can be used in different radiation shielding applications.

关键词： Perovskite Ceramics Gamma ray shielding mass stopping power Rare earths

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Surface activation of viscose textiles via air,argon,and oxygen dielectric barrier discharge plasma:influence of peak voltage

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Plasma Science and Technology 2024年第7期26卷 134-147页

作者： Shrouk ELASHRY Usama m.RASHED mostafa A.WAHBA Hend m.AHmED Nabil m.ELSIRAGY Plasma Laboratory Physics DepartmentFaculty of scienceTanta UniversityTanta 31527Egypt Physics Department Faculty of Science(Male)Al-Azhar UniversityCairo 11651Egypt Textile Research Industrial Division National Research CentreDokkiGiza 12622Egypt

This paper discusses the use of atmospheric pressure dielectric barrier discharge(DBD)plasma treatment to enhance the surface qualities of viscose *** study explores the effects of different plasma gases,discharge voltages,and exposure times on the treated *** findings emphasize the importance of optimizing the plasma's peak voltage to achieve the desired surface treatment *** document also presents data on colour strength,wettability,colour fastness,and tensile strength of the treated fabrics,as well as scanning electron microscopy(SEm)analysis of surface morphology and chemical analysis using fouriertransition infrared spectroscopy(FTIR)and energy dispersive X-ray(EDX).The results show that treatment at a peak voltage of 11.83 k V is more efficient,except for the tensile strength which is enhanced at a peak voltage of 8.92 k *** oxygen plasma treatment significantly improves the colour strength,which exhibits an increase from 11 to *** intensified colour was attributed to the significant influence of electrostatic interactions between the charged hydroxyl groups of the oxygen plasma treated viscose textiles and the dye molecules,which enhance the *** oxygen DBD plasma exhibits a higher ability to enhance the properties of textiles when compared to air and argon *** study presents a sustainable,economical,secure,and ecologically friendly approach to explore new fabrics for specific uses.

关键词： Lissajous diagrams printability wettability tensile strength SEm EDX FTIR

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Exploring the associations between skeletal muscle echogenicity and physical function in aging adults:A systematic review with meta-analyses

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Journal of Sport and Health Science 2024年第6期13卷 820-840页

作者： Dustin J.oranchuk Stephan G.Bodkin Katie L.Boncella michael o.Harris-Love muscle morphology Mechanicsand Performance LaboratoryDepartment of Physical Medicine and RehabilitationUniversity of Colorado Anschutz Medical CampusAuroraCO 80045USA Department of Physical Therapy

Background:Assessment and quantification of skeletal muscle within the aging population is vital for diagnosis,treatment,and injury/disease *** clinical availability of assessing muscle quality through diagnostic ultrasound presents an opportunity to be utilized as a screening tool for function-limiting ***,relationships between muscle echogenicity and clinical functional assessments require authoritative ***,we aimed to(a) synthesize the literature to assess the relationships between skeletal muscle echogenicity and physical function in older adults(≥60 years),(b) perform pooled analyses of relationships between skeletal muscle echogenicity and physical function,and(c) perform sub-analyses to determine between-muscle ***:CINAHL,Embase,mEDLINE,Pubmed,and Web of Science databases were systematically searched to identify articles relating skeletal muscle echogenicity to physical function in older ***-of-bias assessments were conducted along with funnel plot ***-analyses with and without sub-analyses for individual muscles were performed utilizing Fisher's Z transformation for the most common measures of physical ***'s Z was back-transformed to Pearson's r for ***:Fifty-one articles(n=5095,female=~2759,male=~2301,72.5± 5.8 years,mean±SD(1 study did not provide sex descriptors))were extracted for review,with previously unpublished data obtained from the authors of 13 *** rectus femoris(n=34) and isometric knee extension strength(n=22) were the most accessed muscle and physical qualities,*** relationship between quadriceps echogenicity and knee extensor strength was moderate(n=2924,r=-0.36(95% confidence interval:-0.38 to-0.32),p other meta-analyses(grip strength,walking speed,sit-to-stand,timed up-and-go) resulting in slightly weaker correlations(r:-0.34 to-0.23,all p mined minimal differences in predicti

关键词： Correlations Echo intensity Elderly Intramuscular fat Strength

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