Synthesis and characterization of lanthanum-doped curcumin-functionalized antimicrobial copper oxide nanoparticles

Flavonoid-based nanomaterials have extensive potential in antimicrobial research because of their non-toxicity,large-scale producibility,and chemical stability.An efficient combination of flavonoids and rare earth metals can have excellent antimicrobial properties owing to their robust medicinal and physicochemical properties.In this study,we synthesized copper oxide(CuO) nanoparticles(NPs)using a reflux reaction and repeated doping with the rare earth element lanthanum to prepare La-CuO NPs.Nex...     

Advances in gas sensors of tetrapyrrolato-rare earth sandwich-type complexes——Commemorating the 100th anniversary of the birth of Academician Guangxian Xu

In recent years,sandwich-type rare earth tetrapyrrole derivatives,have attracted more and more attention as material for conductimetric sensors.They have not only great chemical stability and processability,but also flexible molecular structure,which is a key to adjustable semiconductor properties.In this mini review,we focus mainly on the development of tetrapyrrolato-rare earth sandwich-type complexes as the semiconducting active layer in the gas sensors published in the last ten years(2010-2020).The main part includes two sections.In the single component gas sensing of sandwich rare earth tetrapyrrole complexes,we describe the influence factors of the single-component semiconducting active layer on the sensing performance of tetrapyrrolato-rare earth sandwich-type complexes,including substituents,central metals and π-conjugate systems.In the multi-component gas sensors,the synergistic effect between tetrapyrrolato-rare earth sandwich-type complex and other materials on improving sensitivity and conductivity has been discussed briefly.     

Dysprosium regulated platinum particles as a bimetallic alloy catalyst for oxygen reduction reaction

Pt rare earth compounds have recently been investigated as potential substitutes.In this study,the hydrogen reduction method was used to prepare the Pt-Dy bimetallic catalyst,and a number of characterizations were conducted for structure and morphological research.The high resolutiontransmission electron microscopy(HR-TEM) and X-ray diffraction results show that Pt-Dy composite material exists in the form of various alloys and has a clear spherical shape.The majority of the metals in the composi...     

Identification of Rare Earth Phase in the Deformed High Lead-Brasses

Deformed high lead-brasses have excellent machining characteristics and good mechanical and physicalproperties.They are widely used in mechanical,clock-watch and pen-making field.Especially,they are suit-able for deep-hole machining.Because of their worse hot-working characteristics,there exists trouble inproduction process.It is reported that the rare earth metals could improve the hot-rolling property,but themechanism is still unclear.     

Dual-functionalization based on combination of quercetin compound and rare earth nanoparticle

While the nanoparticles like La2O3 and other rare earth oxides were believed to be able to provide effective scavenging hydroxyl radical.Quercetin,a hydrophobic agent,showed some potential antibacterial activity.The present work successfully performed the surface modification of rare earth nanoparticle using facile and general strategy.In specific,the hydrophobic quercetin was grafted on the rare earth nanoparticle through the coupling with silane.The surface modified nanoparticle was characterized by Fourier-transform infrared(FTIR),thermogravimetric analysis(TGA),and scanning electron microscopy(SEM).The surface modification helped to retain both the scavenging hydroxyl radical property of rare earth nanoparticle and the antibacterial activity of quercetin.This dual-function properties showed potential for application in the development of biomedicine such as antioxidant,anti-inflammatory,antibacterial and anticancer.     

A review of rare-earth oxide films as high k dielectrics in MOS devices——Commemorating the 100th anniversary of the birth of Academician Guangxian Xu

Recently,rare-earth oxide films have attracted more and more attention as gate dielectrics in metaloxide-semiconductor(MOS)devices,showing the advantages of high dielectric constant(k value),large band gap(Eg)and outstanding physical and chemical stability in contact with silicon substrates.This paper reviews the recent development of rare earth oxide-based gate dielectric films.Aiming at the problem that k value of rare earth oxides(REOs)is generally inversely proportio nal to the band gap value,one of the biggest technical obstacles of high k films,we reviewed three strategies reported in recent papers,namely doping modification,nitriding treatment and multilayer composite,which can provide some insights for long-term development of MOS devices in integrated circuit(IC).     

Global rare earth resources and scenarios of future rare earth industry

It is known to all that China is abundant in rare earth resources.But rare earth deposits are really not that rare in the earth crust.In the five continents,i.e.Asia,Europe,Australia,North and South America,and Africa,there are about thirty four countries found to have rare earth deposits;Brazil might surpass China and rank the first in rare earth deposits.At present,investment in rare earth production was surged,there have been about 200 projects,and the total production for 25 of them would be more than 170 thousand tons after 2015,a multi-supply system on rare earths is being established worldwide.Cautions on the investment of rare earth production are involved.     

Research progress of rare earth separation methods and technologies

Strategical elements,such as rare earth elements,play a crucial role in the industry,especially in producing high-tech materials.Major global industries have developed a strong dependence on rare earth materials.Every year,there are innovations in industries such as modern technology,green energy,or communications technology,which need more strategic metals to improve investment profitability.This article reviews advances in rare earth separation methods and techniques to guide and recommend the...     

Influence of Light Rare Earth on Toughness of Welded Seam of LAHS Steel

The influence mechanism of light rare earth elements, which are transited to the welding seam of low-alloy high strength (LAHS) steel through the covering of the electrode, on the toughness of the welding seam was studied. The experimental results show that proper amount of rare earth elements can desulfurate, dehydrogenate, reduce inclusions and purify the structure of the welding seam. Rare earth element additions have .the effect on welding seam and, at the same time, the transformation of side-batten ferrite is resisted while the pin-ferrite structure is promoted. The improvement of the toughness of the welding seam is due to the purifying action of rare earth elements as well as their refining effect on the structure. However, the toughness of the welding seam can decrease when the amount of light rare earth elements are added excessively because the crystal grains become coarser, porosities appear and the inclusions increase as well. The experimental results show that the suitable amount of light rare earth element additions is about 2%.     

Recent progress on upconversion luminescence enhancement in rare-earth doped transparent glass-ceramics

The upconversion(UC) of the rare earth doped glass-ceramics has been extensively investigated due to their potential applications in many fields, such as color display, high density memories, optical data storage, sensor and energy solar cell, etc. Many series of them, especially the oxyfluorides glasses containing Ba2 LaF 7 nanocrystals were studied in this review work, due to the thermal and mechanical toughness, high optical transmittance from the ultraviolet to the infrared regions, and a low nonlinear refractive index compared to the other commercial laser glasses. Moreover, the energy transfer(ET) between the rare earth ions and transition metals plays an important role in the upconversion process. The cooperative ET has been researched very activly in UC glasses due to applications in the fields of solar cells, such as in the Er/Yb, Tm/Yb, Tb/Yb, Tb/Er/Yb and Tm/Er/Yb couples. The present article reviews on the recent progress made on:(i) upconversion materials with fluoride microcrystals in glasses and the mechanisms involved, including the UC in double and tri-dopant RE ions activated fluoride microcrystal, energy transfer process; and(ii) the effect of the metal Mn and nanoparticles of Au, Ag, Cu on the enhancement of UC emissions. Discussions have also been made on materials, material synthesis, the structural and emission properties of glass-ceramics. Additionally, the conversion efficiency is still a challenge for the spectra conversion materials and application; challenge and future advances have also been demonstrated.     

Phase Behavior and Crystal Structure of Perovskite-Type Rare Earth Complex Oxides

Several compounds of rare earth complex oxides containing manganese and titanium were synthesized in Ar, and their crystal structures were analyzed by powder X-ray diffraction data and Rietveld method. Structures of A0.67Ln0.33 Mn0.33Ti0.6703（A = Ca or Sr and Ln = rare earth） were found to have orthorhombic symmetry with the space group Pnrna, and their interatomic distances and bond angles were obtained. This space group was also derived from electron microscopic study. Electrical conductivity of Cao.67Ln0.33Mn0.33Ti0.6703 for several rare earth elements showed a semiconducting property with the activation energy of 0.4 eV. Some of these compounds of the strontium system show the antiferromagnetic properties below 10 K.     

Preface

<正>The International Conference on RARE EARTH MATERIALS(REMAT),which was organized in Wroc?aw in Poland on 26-28 April,2013 for the third time has undertaken the most recent aspects of novel rare earth materials,their applications and the problems with Rare Earth Elements(REE)supply.The conference was divided into three thematic sessions in which the leading issues were:the recycling of materials containing rare earth ions,mining these rare earth metals and the application of their ions in optical and magnetic materials.It     

Synthesis and applications of lanthanoid complexes of pentadentate and hexadentate N5 and N6 macrocycles:A review

In this paper,the lanthanoid complexes of N₅ and N₆ macrocycle ligands,without pendant arms or additional heteroatoms,are surveyed.This review covers the period from 2015 to the current date,since in 2014 Schiff base macrocyclic ligands incorporating the pyridine moiety,and their complexes,were revised,and in 2015 the chemistry of pentaaza macrocycle ligands with rare earth metals was also summarized.Porphyrin and phthalocyanine ligands are not included in this review,which...     

Comparative Crystal Chemistry of Rare Earth Minerals

Polyhedral analysis is used to study the geometrical limits of the crystal structure on isomorphic substitutionof rare earths.The rare earth sites in the structure may be distinguished into six groups on the basis of meanionic radii of the substituting cations in each rare earth site:Y,Y+Ca,REE,REE+Ca,Ce+Ca,Ce.The calcula-tion of volumes of 70 rare earth polyhedra indicates that the polyhedral volumes of the heavy rare earth are in arange of 13×10~(-3)～28×10~(-3) nm~3,the volumes of light rare earth polyhedra are in 20×10~(-3)～40×10~(-3) nm~3,and the polyhedral sizes suitable to isomorphic substitution of all REE are about 21×10~(-3)～29×10~(-3) nm~3.Thesize of REE polyhedra depends on mean ionic radii in REE sites,coordination number and linkage of polyhedra.In structures where exist two kinds of polyhedra,with the change of composition in REE site,both REEpolyhedron and anion group polyhedron tend to be more distorted,leading to the change of structural symmetry.The contrary distortion tendencies of both polyhedra favours the stability of the structure.The phenomena maybe interpreted by the potential energy distribution or the potential energy compensating mechanism of thecrystal.     

Doping Effects of Rare Earth on Dielectric Properties of Fine－Grained BaTiO3－Based Ceramics

The doping effects of rare earth oxides Ho2O3 and Er2O3 on dielectric properties of BaTiO3-based ceramics were studied. After adding rare earth elements, grain growth in this system was inhibited and the grain size was reduced evidently which realized the fine-grained effect. In this system, the trivalent oxides Ho2O3 and Er2O3 were added to BaTiO3 ceramics. The rare earth oxides do not enter into inner lattice totally to replace A or B sites.Some of additives can improve dielectric strength by forming nonferroelectric phases, and the rest maintained at grain boundaries controls overgrowth of grains. The dielectric constant at room temperature is increased up to 3000 and the curve of TCC becomes flat.Meanwhile, the dielectric strength Eb becomes higher.     

Effect of Cycling Loaded Rare Earths on Stripping Process in P507 Extraction System

P507 （HEH [EHP]） is an important extractant for the separation of rare earth and is widely used in industry. Since the complexes of heavy rare earth ions with saponified P507 are so stable that the rare earth ions are difficult to be exchanged and stripped by H^＋ ions. Thus, the cycled extractant loads certain amount of heavy rare earth ion after stripped by acid. This amount of rare earth ions loaded in blank organic phase is named as the ＂cycling loaded rare earth ions （CLREs）＂. In the separation process of Tm^3＋, Yb^3 ＋, and Lu^3 ＋ , the amount of CLREs carl be more than 10% of the normal capacity of saponifiedorganic phase. In fact, CLREs affect the separation efficiency and decrease the purity of the products. Based on the extracting-stripping equilibrium and mass balance, the influence of different process parameters on the amount of CLREs was studied by computer simulation. The results indicate that higher acid consumption and more stripping stages are required to eliminate CLREs. For an industrial practice, however, the acid consumption and the number of stripping stage can be designed by choosing an economic process and controlling CLREs at a reasonable level.     

Correlation Studies of Rare Earth Elements in Syntectonic Intrusions of Strike-Slip Stage along Southern Segment of Tan-Lu Fault Zone

Intrusions in the Zhangbaling uplift zone and the eastern margin of the Dabie orogenic belt belong to the svntectonic intrusions developed during the strike-slip stage in the southern segment of the Tan-Lu fault zone. However, characteristics of rare earth elements show that intrusions in the Zhangbaling uplift zone have the characteristics of mantle source type and those in the eastern margin of Dable belt are the typical crust source type. Therefore, Au-deposits related to the intrusions in the Zhangbaling uplift zone are developed better than those in the eastern margin of the Dabiesban. The research results of the rare earth elements coincide with the studies of geophysics, tectonic setting and stable is otope. It isfurther indicated that the rare earth elements offer effective approach to tracing the material sources of magmatic rocks.     

Rare earth recovery from fluoride molten-salt electrolytic slag by sodium carbonate roasting-hydrochloric acid leaching

Fluorinated rare earth molten-salt electrolytic slag contains a considerable amount of rare earth elements,as well as a variety of heavy metals and fluorides that cause environmental pollution.Therefore,it is of great importance to fully utilise this resource.In this study,the transformation mechanism of fluorinated rare earth molten-salt electrolytic slag roasted with sodium carbonate,and the regulation mechanism of rare earth leaching under different roasting conditions were investigated with ...     

A review of fractionations of rare earth elements in plants

Studies were carried out on several aspects of rare earth elements （REEs）, such as the theory and practice of their applications in agriculture, their geochemical behaviors in natural and agricultural ecosystems, the mechanisms for the increase of crop yield using REE fertilizer, and their toxicology. However, limited knowledge was available for the transfer processes and the features and mechanisms of distribution and fractionations of REEs inside plants. The characteristics of REE fractionations in plants can be used to ＂trace＂ the pathway of REE transportation from soils （solution） to plants. A better understanding of the mechanisms of REE fractionations was helpful to investigate the controlling factors, including both the internal and the external ones. The characteristics and mechanisms of REE fractionations in plants and their significance were reviewed. Furthermore, the prospect for these fields was discussed, in hope of providing a new way in studying the bioavailability of REEs and heavy metals.     

Potential application of graphene oxide and Aspergillus niger spores with high adsorption capacity for recovery of europium from red phosphor,compact fluorescent lamp and simulated radioactive waste

The recovery of rare earth elements(REEs) is a global challenge and the mining of rare earths has serious environmental implications due to the toxic waste released post mining.Hence,the rising demand for rare earths and their far reaching electronic applications necessitates an effective strategy to recover the REEs from more viable sources.In this work,the graphene oxide-Aspergillus niger spores(GO-A.niger spores) blend was utilized for adsorptive recovery of a precious rare earth Eu(Ⅲ) and th...