Stability and morphology-dependence of Sc3+ ions incorporation and substitution kinetics within ZnO host lattice

In this study, sol–gel spin coating route was carried out to prepare Scandium doped ZnO thin films with different controlled percentage (1–7%). Particularly, it has been demonstrated, through original conjoint morphological-structural and optical investigations, that some interesting physical properties were induced. Indeed, X-ray diffraction (XRD) analysis shows that (002) preferential crystalline plane for Sc doped ZnO films was kept along with ZnO hexagonal würtzite structure, although Sc doping seemed to cause a decrease in crystallinity. Except for 1 at% Sc doping ratio, optical band gap changes reversely with Urbach energy with a decrease in optical gap and a broadening of the absorption tail. Ab-initio calculations of lattice dynamical properties outlined additional strong hybridization between Sc and O atoms and show the stability of Scandium doped ZnO.     

Selection of promising quaternary candidates from Mg–Mn–(Sc, Gd, Y, Zr) for development of creep-resistant magnesium alloys

Recently developed Mg–Mn–Sc alloys show a considerable increase of creep resistance at elevated temperature. The endeavor to further improve the properties and to reduce cost of high-price Sc metal initiated a search for additional alloying elements. Gd, Y and Zr were considered for this purpose. The aim is to achieve a large quantity of suitable precipitations to improve mechanical properties using a minimum of expensive alloy element addition. The huge amount of possibilities of combining the elements Mg–Mn–(Sc, Gd, Y, Zr) and the time and cost effort of technological experiments require a preselecting of systems and alloy compositions. Thermodynamic phase diagram and phase amount calculations were performed to give hints for selecting promising candidates. A priority list of three quaternary systems is established: Mg–Mn–Gd–Sc, Mg–Mn–Sc–Y and Mg–Mn–Y–Zr, based on the classification of individual alloys. Most promising is MgMn1Gd5Sc0.8 (wt.%), but the alloys MgMn1Gd5Sc0.3 and MgMn1Y5Sc0.8 are also promising. The entire quaternary Mg–Mn–Y–Zr system is disqualified because of phase diagram features that are detrimental for the required microstructural engineering. The focused alloy development following this approach avoids a waste of time and effort.     

Novel Sc-doped Bi3TiNbO9 ferroelectric nanofibers prepared by electrospinning for visible-light photocatalysis

In this work,a novel Sc-doped Bi₃TiNbO₉ ferroelectric nanofiber was first prepared by electrospinning.The nanofibers are approximately 100 nm level in diameter.The photocatalytic activity analysis reveals that the Bi₃TiNbO₉ nanofibers synthesized by electrospinning are superior to powders prepared by the solid-state method,which is mainly attributed to the high specific surface area and high surface activity of the nanofibers.In addition,doping Sc can ...     

Solution combustion synthesis of iron-deficient Sc2-xFexO3 (x = 0.17-0.47) nanocrystals with bixbyite structure: The effect of spatial constraints

In this paper, nanopowders based on iron-deficient Sc_2-xFe_xO₃ (x = 0.17–0.47) nanocrystals with bixbyite structure and crystallite size of 3.7–38.9 nm were successfully synthesized via solution combustion. Variable glycine-to-nitrate (G/N) ratio was the main controlling factor. A wide range of experimental and computational methods were used to analyze the impact of spatial constraints on the resulting solid-state products. It was found that solution combustion mode greatly influenced on the temperature and gaseous products in the reaction zone. Volume (G/N = 0.4–0.8, T_max = 1179–1511 °C), self-propagating (G/N = 1.0–1.4, T_max = 614–957 °C) or smoldering (G/N = 0.2, T_max = 443 °C) combustion modes were acquired during the synthesis depending on G/N ratio. It was shown that the formation of impurity phases of am-Fe₂O₃ (T_max < 850 °C), c-Fe₃O₄ (900 °C < T_max < 1500 °C) or c-FeO (T_max > 1500 °C) was possible, depending on the combustion temperature. Besides, the combustion mode affected the porous and surfacial structure of resulting mesoporous nanopowders – specific surface area and total pore volume varied in ranges of 1.7–82.8 m²/g and 0.0088–0.1538 cm³/g, consequently. Chemical composition and unit cell parameters of Sc_2-xFe_xO₃ showed the positive deviation from Vegard's law. The average sizes of the interpore thickness (h) depending on G/N ratio were found from values of specific surface area and pycnometric density of nanopowders, which made it possible to establish the presence of spatial constraints for the crystals' growth of Sc_2-xFe_xO₃ at h values below 10 nm. Analysis of aspect (h/D) ratio allowed to determine synthetic parameters which led to mono- or polycrystalline structure of interpore space in resulting Sc_2-xFe_xO₃-based nanopowders. The results and patterns established in this paper allowed to synthesize a new type of foam-like functional materials based on rare-earth ferrites.     

Effects of scandium chloride on osteogenic and adipogenic differentiation of mesenchymal stem cells

Mesenchymal stem cells(MSCs)are multi-potent cells that are able to differentiate and mature into various types of cells under a certain microenvironment for cell therapy and tissue regeneration.Scandium(Sc),an important rare earth element,recently has been intensively investigated in biomedical fields as well as industrial engineering,and chloride channels have been proven to be able to affect osteogenic differentiation.Thus,it is significant to investigate effects of ScCl₃on cell activities of MSCs.In this paper,rat bone MSCs(rBMSCs)were co-cultured with various concentrations of ScCl₃(1×10^-8,1×10^-6,and 1×10^-4mol/L)to evaluate their influence on cell proliferation as well as osteogenic and adipogenic differentiation in vitro.The results indicate that ScCl₃promotes the proliferation of rBMSCs initially,which is yet reduced upon ion accumulation.We used immunofluorescence staining,quantitative real time polymerase chain reactions,and assays measuring alkaline phosphatase activity,mineralized deposits,and intracytoplasmic lipids to reveal that rBMSCs treated with ScCl₃at concentrations of 1×10^-8-1×10^-6mol/L can enhance levels of osteogenic differentiation in a dosedependent manner and reduce adipogenic differentiation to a certain degree through Wnt/β-catenin signaling pathway.These results indicate that appropriate concentrations of ScCl₃can improve osteogenic differentiation in the lineage commitment of rBMSCs,and thus,promote bone remodeling.This study implies that ScCl₃ possesses great potentials in the treatment of bone diseases and would provide new strategy of designing composites by SiCl3 doping for biomedical applications in the future.     

Some comments on the misfit and coherency loss of Al3Sc particles in Al–Sc alloys

An attempt of refining a recently reported calculation of the temperature dependent misfit between Al and Al₃Sc particles is given. Further, the impact of a temperature dependent misfit on the calculated diameter for coherency loss of Al₃Sc precipitates is demonstrated. The origin of misfit dislocations is also briefly discussed.     

某铁矿床中铁钴矿物的工艺矿物学研究

这是一篇工艺矿物学领域的论文。滇南地区某钒钛磁铁矿矿石不仅有较高的铁、钛,而且伴生钪元素。为实现矿石综合利用,对该矿进行了工艺矿物学研究。采用X 射线荧光光谱分析及化学分析手段,查明了矿石化学成分;利用X 射线衍射分析仪（XRD）、扫描电镜与能谱分析（SEM-EDS）、电子探针（EPMA）等方法,研究了矿物的工艺特征,重点考查了铁、钛元素的赋存状态。研究结果表明：矿石中铁的主要载体矿物为钛磁铁矿、角闪石,其次为钛铁矿;钛的载体矿物主要为钛铁矿,少量赋存于榍石中;钪主要分布在角闪石中。元素配分结果表明,铁、钛的理论品位分别为71.02%、47.40%,理论回收率分别为40.52%、66.48%。分析了影响选矿回收指标的矿物学因素,为后续选冶工艺提供了理论支撑。     

Separation of 47Sc produced from natCa(n, γ) reaction for potential medical applications by a synthesized raspberry-like structure of metal-organic framework material

This work aimed for the synthesis of a novel metal organic framework through a facile and gamma-irradiation process to be applied for the separation of scandium-47 as theranostic radioisotope from the irradiated calcium target. Polyacrylonitrile-cupric oxide nanocomposite structure (as metal organic framework) was successfully synthesized and characterized. The optimized conditions (such as monomer concentration, weight of cupric oxide nanoparticles and gamma-dose) for the synthesis of polyacrylonitrile-cupric oxide were identified. The newly synthesized resin was used to study the separation of micro amounts of scandium-47 from gram amounts of the irradiated calcium carbonate by batch equilibration and column studies. Preliminary study demonstrated that the Kd values of scandium(III) ions are little higher than that of calcium(II) ions. The elution yield of scandium-47(III) was found to be 61±2 %. Future work will be done to improve this yield for nuclear medicine applications.     

西昌三圆石材厂废料中高钪矿物的浮选试验

随着社会的快速发展,钪资源已经成为重要的战略资源。目前,可供直接利用的资源殆尽,所以利用选矿富集的方法成为资源有效利用的关键。西昌三圆石材废料中Sc2O3品位为68g/t,达不到生产要求,因此需要对矿石进行富集回收。工艺矿物学研究表明,辉石和角闪石中Sc2O3的含量相对较多,二者是选矿回收的主要载钪矿物。本文通过磨矿细度、捕收剂的pH试验和药剂用量试验,确定采用“一粗一扫一精,精选尾矿再扫”的浮选流程;最终在磨矿细度为-200目占95%;粗选油酸钠用量250g/t,氢氧化钠用量2200g/t;扫选油酸钠用量150g/t,氢氧化钠用量500g/t的条件下,获得Sc2O3精矿品位为79.75g/t,回收率为65.11%的较好指标,旨在为钪的回收利用提供一定的借鉴意义。     

Electrical characterization of high-pressure reactive sputtered ScOx films on silicon

Al/ScO_x/SiN_x/n-Si and Al/ScO_x/SiO_x/n-Si metal-insulator-semiconductor capacitors have been electrically characterized. Scandium oxide was grown by high-pressure sputtering on different substrates to study the dielectric/insulator interface quality. The substrates were silicon nitride and native silicon oxide. The use of a silicon nitride interfacial layer between the silicon substrate and the scandium oxide layer improves interface quality, as interfacial state density and defect density inside the insulator are decreased.