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Condensed point defects enhance thermoelectric performance of rare-earth Lu-doped GeTe

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Journal of Materials Science & Technology 2023年第20期151卷 227-233页

作者： Wan-Yu Lyu Wei-Di Liu Meng Li Xiao-Lei Shi Min Hong Tianyi Cao Kai Guo Jun Luo Jin Zou Zhi-Gang Chen Centre for Future Materials University of Southern QueenslandSpringfieldQueensland 4300Australia School of Chemistry and Physics Queensland University of TechnologyBrisbaneQueensland 4000Australia Australian Institute for Bioengineering and Nanotechnology The University of QueenslandBrisbaneQueensland 4072Australia School of Physics and Materials Science Guangzhou UniversityGuangzhou 510006China School of Materials Science and Engineering Shanghai UniversityShanghai 200444China School of Mechanical and Mining Engineering The University of QueenslandBrisbaneQueensland 4072Australia Centre for Microscopy and Microanalysis The University of QueenslandBrisbaneQueensland 4072Australia

Heavy rare-earth element doping can effectively strengthen phonon scattering,suppress the lattice thermal conductivity,and enhance the overall thermoelectric performance of GeTe.However,the large electronegativity difference between rare-earth elements(such as La,Eu,and Gd)and Ge refrains the doping limit of rare-earth elements below 1 mol.%in GeTe.Here,compared with other rare earth elements,Lu was found to have a relatively small radius and electronegativity difference with Ge,which can induce a high doping level in GeTe.The result shows that Lu doping effectively reduces the lattice thermal conductivity from 0.77 W^(−1) m K^(−1) of GeTe to 0.35 W m^(−1) K^(−1) of Ge_(0.98)Lu_(0.02)Te at 673 K,and further induces a high zT value of 1.5 in Ge_(0.98)Lu_(0.02)Te at 673 K.Extra Sb alloying optimizes the carrier concentration from 1.02×10^(21) cm^(−3) of Ge_(0.98)Lu_(0.02)Te to 1.77×10^(20) cm^(−3) of Ge0.90Lu0.02Sb0.08Te,which results in a reasonable power factor of 33.82μW cm^(−1) K^(−2) and a low electrical thermal conductivity of 0.75 W m^(−1) K^(−1) at 673 K in Ge_(0.90)Lu_(0.02)Sb_(0.08)Te.Correspondingly,a peak zT of 1.75 at 673 K and an average zT of 0.92 within the temperature range of 303–723 K are obtained in Ge_(0.9)Lu_(0.02)Sb_(0.08)Te.This study indicates that Lu and Sb co-doping can effectively boost the thermoelectric performance of GeTe-based thermoelectric materials.

关键词： Thermoelectric rare-earth Thermal conductivity Carrier concentration

Advance in the chemical synthesis and magnetic properties of nanostructured rare-earth-based permanent magnets

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rare Metals 2013年第2期32卷 105-112页

作者： Ce Yang Yang-Long Hou Department of Materials Science and Engineering College of EngineeringPeking University

rare-earth-based permanent magnets are one of the most important magnets in both scientific and industrial fields. With the development of technology, nanostructured rarearth-based permanent magnets with high energy products are highly required. In this article, we will review the progress in chemical synthetic strategies of nanostructured rare-earth-based permanent magnets.

关键词： rare-earth Permanent magnets Chemicalsynthesis

rare-earth and trace elements and hydrogen and oxygen isotopic compositions of Cretaceous kaolinitic sediments from the Lower Benue Trough, Nigeria: provenance and paleoclimatic significance

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Acta Geochimica 2019年第3期38卷 350-363页

作者： Anthony T.Bolarinwa Sunday O.Idakwo David L.Bish Department of Geology University of Ibadan Department of earth Sciences Kogi State University Department of Geological Sciences Indiana University

This study evaluated the Cretaceous(Campanian–Maastrichtian) kaolinitic sediments of the Ajali/Mamu and Enugu/Nkporo Formations from the Lower Benue Trough of Nigeria. A combined method of inductively coupled plasma–mass spectrometry and isotope ratio mass spectrometry was used to investigate trace and rareearth element geochemistry and hydrogen and oxygen isotopic compositions. These data were then used to infer the sediments' provenance and paleoclimatic conditions during their deposition. The sediments contained low concentrations of most trace elements, with the exceptions of Zr(651–1352 ppm), Ba(56–157 ppm), V(38–90 ppm),and Sr(15.1–59.6 ppm). Average values of Co and Ni were1.5 and 0.7 ppm, respectively. Trace and rare earth element values were lower than corresponding values for upper continental crust and Post-Archean Australian Shale, with the exception of Zr. The samples showed only slight light rare-earth enrichment and nearly flat heavy rare-earth depletion patterns, with negative Eu and Tm anomalies,typical of felsic sources. Geochemical parameters such as La/Sc, Th/Sc, and Th/Co ratios support that the kaolinitic sediments were derived from a felsic rock source, likely deposited in an oxic environment.^(18 )O values ranged from+ 15.4 to + 21.2% for the investigated samples, consistent with a residual material derived from chemicalweathering of felsic rock and redeposited in a sedimentary basin(typical values of + 19 to + 21.2%). While in the basin, the sediments experienced extended interactions with meteoric water enriched in d D and d16 O. However,the variation in d D and d16 O values for the investigated samples is attributed to the high temperature of formation(54–91 °C). The d D and d^(18 )O values suggest that the sediments, although obtained from different localities within the Lower Benue Trough, formed under similar hot,tropical climatic conditions.

关键词： rare-earth and trace elements Oxygen/ hydrogen isotopic composition Kaolinitic sediments Lower Benue Trough Nigeria

Recovery of rare-earth metals from aqueous solutions by bio/adsorption using non-conventional materials:a review with recent studies and promising approaches in column applications

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Journal of rare earths 2020年第4期38卷 339-355页

作者： Talles Barcelos da Costa Meuris Gurgel Carlos da Silva Melissa Gurgel Adeodato Vieira University of Campinas School of Chemical EngineeringAlbert Einstein Avenue50013083e852 CampinasBrazil

The recovery of rare-earth metals(REMs)is of great economic and environmental interest,because of their high market prices and various industrial applications.Recently,with the increasing demand for high-purity rare-earth compounds,the separation and purification of these elements have gained considerable attention.The bio/adsorption process has been considered an alternative to recover these elements,by its simplicity,low cost and efficiency for recovery of REMs at low concentrations.This review article presents the recent progress regarding REM bio/adsorption published literature in batch system by different non-conventional bio/adsorbents,as well as a critical analysis of the technological challenges to be faced and future prospects.For this purpose,the best application model(isotherm,kinetics),thermodynamic quantities and selection of eluents for desorption studies are also discussed.Additionally,in this review,the application of different bio/adsorbent materials were reviewed extensively in terms of the removal and recovery of REMs in continuous fixed-bed adsorption and regeneration cycles.Finally,future aspects in bio/adsorption research and prospects for commercial applications were discussed.

关键词： rare-earth metals Bio/adsorbents Adsorption kinetics Isotherm Batch desorption Continuous fixed-bed adsorption

Substituent Effects of Pyridyl-methylene Cyclopentadienyl rare-earth Metal Complexes on Styrene Polymerization

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Chinese Journal of Polymer Science 2019年第6期37卷 570-577页

作者： Zhen Zhang Zhong-Yi Cai Yu-Peng Pan Yan-Li Dou Shi-Hui Li Dong-Mei Cui Key Laboratory of Automobile Materials of Ministry of Education Department of Materials Science and Engineering Jilin University State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences

Salt metathesis reactions between pyridyl-methylene-cyclopentadienyl lithium salt and LnCl_3 followed by the addition of two equivalents of LiCH_2SiMe_3 afforded a series of constrained-geometry-configuration rare-earth metal bis(alkyl) complexes(Cp′CH_2-Py)Ln(CH_2SiMe_3)_2(THF)_n(Py = C_5H_4N, Cp′ = C_5H_4(Cp), Ln = Sc, n = 0(1); Cp′ = C_9H_6(Ind), Ln = Sc, n = 0(2); Cp′ = 3-Me_3Si-C_9H_5(3-Me_3Si-Ind), Ln = Sc, n = 0(3a), Ln = Lu(3b), Y(3c), n = 1; Cp′ = 2,7-(~tBu)_2C_(13)H_8(2,7-(~tBu)_2-Flu), Ln = Sc(4 a), n = 0, Ln = Lu(4b),Y(4c), n = 1) in moderate to good yields, which were characterized by NMR spectroscopy and single-crystal X-ray diffraction(for complex 3a). In the presence of [Ph_3C][B(C_6F_5)_4] and Al^iBu_3, these complexes displayed different performances towards styrene polymerization. rare-earth metal bis(alkyl) precursors bearing Cp, Ind, and 3-Me_3Si-Ind segments exhibited very low catalytic activity to afford syndiotactic polystyrene. All electron-donating t Bu substituted complexes 4 a, 4 b, and 4 c showed very high activity and perfect syndiotactivity(rrrr > 99%), producing high molecular weight polystyrene(up to 54.1 × 10~4) with relatively narrow molecular distribution(PDI = 1.28-2.49).

关键词： Polystyrene Syndiotactic rare-earth metal Constrained-geometry configuration

Component Content Soft-sensor Based on Neural Networks in rare-earth Countercurrent Extraction Process

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自动化学报 2006年第4期32卷 489-495页

作者： YANG Hui CHAI Tian-You School of Electronics and Electrical Engineering East China Jiaotong University Nanchang 330013 Research Center of Automation Northeastern University Shenyang 110004

Throught fusion of the mechanism modeling and the neural networks modeling,a compo- nent content soft-sensor,which is composed of the equilibrium calculation model for multi-component rare earth extraction and the error compensation model of fuzzy system,is proposed to solve the prob- lem that the component content in countercurrent rare-earth extraction process is hardly measured on-line.An industry experiment in the extraction Y process by HAB using this hybrid soft-sensor proves its effectiveness.

关键词： rare-earth countercurrent extraction soft-sensor equilibrium calculation model neural networks

rare-earth metal catalysts for alkene hydrosilylation

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Science China Chemistry 2019年第5期62卷 571-582页

作者： Deshuai Liu Boyu Liu Zexiong Pan Jianfeng Li Chunming Cui State Key Laboratory of Elemento-organic Chemistry and College of Chemistry Nankai University Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)

rare-earth metal catalyzed hydrosilylation of alkenes has emerged as a powerful and selective strategy for the synthesis of organosilanes. This transformation can offer distinctive catalytic sequences and reaction patterns from other catalysts because of the high electropositivity and lack of oxidative-addition process of rare-earth metal. This review summarizes the rare-earth metal catalysts for hydrosilylation of alkene according to the type of ligands. The synthesis and structure of rare-earth metal catalysts,the substrate scope as well as some preliminary structure-activity relationship and mechanism are discussed.

关键词： rare-earth metal hydrosilylation alkene catalysis mechanism

Interplay of iron and rare-earth magnetic order in rare-earth iron pnictide superconductors under magnetic field

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Chinese Physics B 2016年第2期25卷 446-453页

作者：杨雷雷刘大勇陈东猛邹良剑 Key Laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences College of Science China University of Petroleum Department of Physics University of Science and Technology of China

The magnetic properties of iron pnictide superconductors with magnetic rare-earth ions under strong magnetic field are investigated based on the cluster self-consistent field method. Starting from an effective Heisenberg model, we present the evolution of magnetic structures on magnetic field in RFeAsO（R = Ce, Pr, Nd, Sm, Gd, and Tb） and RFe_2As_2（R =Eu） compounds. It is found that spin-flop transition occurs in both rare-earth and iron layers under magnetic field, in good agreement with the experimental results. The interplay between rare-earth and iron spins plays a key role in the magneticfield-driven magnetic phase transition, which suggests that the rare-earth layers can modulate the magnetic behaviors of iron layers. In addition, the factors that affect the critical magnetic field for spin-flop transition are also discussed.

关键词： iron pnictide superconductors rare-earth magnetic field spin-flop transition

Unloading behaviors of the rare-earth magnesium alloy ZE10 sheet

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Journal of Magnesium and Alloys 2021年第3期9卷 927-936页

作者： Weiqin Tang Jeong Yeon Lee Huamiao Wang Dirk Steglich Dayong Li Yinghong Peng Peidong Wu State Key Laboratory of Mechanical Systems and Vibration Shanghai Jiao Tong University800 Dongchuan RoadShanghai 200240PR China Department of Materials Science and Engineering Korea UniversitySeoul 02841Republic of Korea Institute of Materials Research Materials Mechanics/ACE-CentreHelmholtz-Zentrum GeesthachtMax-Planck-Str.121502 GeesthachtGermany Materials Genome Initiative Center Shanghai Jiao Tong University200240China Department of Mechanical Engineering McMaster UniversityHamiltonOntario L8S 4L7Canada

Due to their low symmetry in crystal structure,low elastic modulus(~45 GPa)and low yielding stress,magnesium(Mg)alloys exhibit strong inelastic behaviors during unloading.As more and more Mg alloys are developed,their unloading behaviors were less investigated,especially for rare-earth(RE)Mg alloys.In the current work,the unloading behaviors of the RE Mg alloy ZE10 sheet is carefully studied by both mechanical tests and crystal plasticity modeling.In terms of the stress-strain curves,the inelastic strain,the chord modulus,and the active deformation mechanisms,the substantial anisotropy and the loading path dependency of the unloading behaviors of ZE10 sheets are characterized.The inelastic strains are generally larger under compressive Loading-Un Loading(L-UL)than under tensile L-UL,along the transverse direction(TD)than along the rolling direction(RD)under tensile L-UL,and along RD than along TD under compressive L-UL.The basal slip,twinning and de-twinning are found to be responsible for the unloading behaviors of ZE10 sheets.

关键词： Inelasticity Magnesium alloy rare-earth Crystal plasticity Twinning Detwinning