查看更多>>摘要：Photothermal conversion is one of the key technologies in solar energy collection,seawater desali-nation,photothermal treatment and other important fields.In order to develop next generation photothermal materials,four polyoxometalates,[(CH3)2NH2]12H5[Ni3Mo18O54(HPO3)10(PO4)]·18H2O(Compound 1),[(CH3)2NH2]1 Na11[Ni2Mo8O22(HPO3)10]·16H2O(Compound 2),Na15(OH)5[Mo6O18(HPO3)4]2[MoO]1.5·16H2O(Compound 3),[(CH3)2NH2]4Na11[Na[Mo6O15(HPO3)4]2]·18H2O(Com-pound 4),are successfully designed and synthesized via a microwave-assisted reaction protocol.Compounds 1-4 not only exhibit broad absorption and notable photothermal conversion effects in near-infrared(NIR)region,but also have high photothermal conversion efficiencies and high quality NIR photothermal imaging effects under NIR laser irradiation.Compound 1 shows the best photothermal conversion effect,and it provides a unique model to explore the relationship between the complex metal oxide structure and photothermal conversion behavior at the molecular level.Both the experimental results and theo-retical calculations consistently conclude that the charge and degree of electron delocalization on the Cluster have a robust influence on the photothermal conversion,as well as the aggregation microstructures.
查看更多>>摘要：The magnetic properties of Ho6MnBi2 and Ho6FeBi2 crystals are investigated by means of density functional theory.These materials are currently an active subject of research in the context of magnetic refrigeration applications since they exhibit a remarkable magnetocaloric effect.In this work,the equation of state,density of states and magnetic moments are calculated and compared with pre-vious experimental results for these materials.Also,the Curie temperatures for the paramagnetic to ferromagnetic phase transition observed in these systems are calculated from first principles.All the calculated quantities are in reasonable agreement with experimental data,which sug-gests that density functional theory could provide a reliable framework to theoretically investigate the magnetic prop-erties of intermetallic ternary compounds.
查看更多>>摘要：Ni56FexGa44-x(15 ≤ x ≤ 20)alloys were stud-ied with the phase structure and magnetic properties.The martensitic transformation was observed over the whole composition range.The martensitic transformation starting temperature(Ms)increases from 256 K for x=15 to 350 K for x=18 and then decreases from 350 K for x=18 to 333 K for x=20 by increasing substitution of Fe for Ga.The austenitic Curie temperature(TAC)is observed for 15 ≤ x ≤ 16 and 18 ≤ x ≤ 20,respectively.And the martensitic Curie temperature(TMC)is observed for x=17.For 18＜x＜20,the austenitic Curie temperature(TAC)is detected at about 499 K,resulting in a relationship between martensite transformation temperature and Curie tempera-ture as TAC＜Ms.For x=17,the relationship between martensite transformation temperature and Curie tempera-ture is TAC＜Ms.
查看更多>>摘要：A new Cu-Cr-Sc alloy was designed,prepared and subjected to deformation heat treatment.Transmission electron microscopy(TEM),electron backscatter diffrac-tion(EBSD)and X-ray diffraction(XRD)were employed to investigate the effects of Sc on the microstructural changes in the Cu-Cr alloy in different states,examine the changes in the precipitates during aging,reveal the intrinsic correlation between the structure and property in the peak aging state,and evaluate the Sc distribution in the Cu-Cr alloy.The addition of Sc significantly increased the yield strength of the Cu-Cr alloy by～24.6％after aging at 480 ℃ for 1 h,while it had a high electrical conductivity of 81.5％international annealed copper standard(IACS).This enhancement was attributed to the effective inhibition of Cr phase coarsening and recrystallization through the addition of Sc,which strengthened the alloy.Furthermore,in the Cu-Cr-Sc alloy,most of the Sc atoms precipitated as the Cu4Sc phase,with a small amount of Sc segregating at the grain boundaries to pin them.This grain boundary pinning helped to inhibit grain growth and further improve the strength.The main strengthening mechanisms identified in Cu-Cr-Sc alloys were dislocation strengthening and pre-cipitation strengthening.
查看更多>>摘要：This study analyzed the prevalent physico-chemical phases of smelting slag from the perspective of data science and chemistry.Findings delineated the silicate phase as the pivotal and predominant constraining phase for the resource utilization of smelting slag.An intricate correlation between metallic elements and dominant phases was constructed.Typical silicate phase olivine(OL)was synthesized as a paradigm to examine alkali depolymer-ization,unveiling the optimal conditions for such depoly-merization to be an alkali to olivine molar ratio of 1:5,a reaction temperature of 700 ℃,and a duration of 3 h.The underlying mechanism of alkali depolymerization within silicate phases was elucidated under these parameters.The reaction mechanism of alkali depolymerization within sil-icate phases can be encapsulated in three sequential steps:(1)NaOH dissociation and subsequent adsorption of OH-to cationic(Mg or Fe)sites;(2)disruption of cation-oxygen bonds,leading to the formation of hydroxide compounds,which then underwent oxidation;(3)Na+occupied the resultant cation vacancy sites,instigating further depoly-merization of the intermediate Na2(Mg,Fe)SiO4.The articulated mechanism is anticipated to furnish theoretical underpinnings for the efficacious recuperation of metals from smelting slags.
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