Transmission electron microscopy （TEM） study of SrPt2As2 reveals two incommensurate modulations appearing in the charge-density-wave （CDW） state below TCDW ≈ 470 K. These two structural modulations can be well ex...Transmission electron microscopy （TEM） study of SrPt2As2 reveals two incommensurate modulations appearing in the charge-density-wave （CDW） state below TCDW ≈ 470 K. These two structural modulations can be well explained in terms of condensations of two-coupled phonon modes with wave vectors of q1=0.62a＊ on the a＊-b＊ plane and q2 = 0.23a＊ on the a＊-c＊ plane. The atomic displacements occur along the b-axis direction for q1 and along the c-axis direction for q2, respectively. Moreover, the correlation between ql and q2 can be generally written as q1 = （q2 ＋ a＊）/2 in the CDW state, suggesting the presence of essential coupling between q1 and q2. A small fraction of Ir doping on the Pt site in Sr（Pt1-xIrx）2As2 （x ≤ 0.06） could moderately change these CDW modulations and also affect their superconductivities.展开更多
Multifunctional TiO2/Ag composite nanowires are fabricated with a hydrothermal method by precipitating Ag nanoparticles （NPs） on the surfaces of TiO2 nanowires. This hierarchical one-dimensional （1D） nanostructure...Multifunctional TiO2/Ag composite nanowires are fabricated with a hydrothermal method by precipitating Ag nanoparticles （NPs） on the surfaces of TiO2 nanowires. This hierarchical one-dimensional （1D） nanostructure can be used as a surface enhanced Raman scattering （SERS） substrate with high sensitivity, for detecting the rhodamine 6G （R6G） in a wide range of low concentrations （from 1 × 10 6 M to 1 × 10-12 M）. In addition, the substrate can be self-cleaned under the irradiation of ultraviolet （UV） light due to the superior photocatalytic capacity of the TiO2/Ag composite nanostructure, making the recycled use of SERS substrates closer to reality. With both the evident SERS performance and high efficiency of photocatalytic capacity, such TiOz/Ag composite nanowires demonstrate considerable potential in the chemical sensing of organic pollutants.展开更多
Snperconductivities and structural properties of Ti-Zr-Ta ternary alloys are extensively investigated. The TiZrTa sample has a cubic structure （β-phase） and shows a sharp superconducting transition at a critical te...Snperconductivities and structural properties of Ti-Zr-Ta ternary alloys are extensively investigated. The TiZrTa sample has a cubic structure （β-phase） and shows a sharp superconducting transition at a critical temperature （To） of about 7.3 K. In addition, two series of Ti-Zr-Ta alloys, with nominal compositions of Ti65-xZr35Tax and TixZr65-xTa35 respectively,are prepared, and their superconductivities and crystal structures change regularly with the chemical composition. Our experimental study also indicates that the annealing processing of this kind of material can cause the transition temperature to increase and the highest Tc is observed to be about 8.3 K in annealed samples.展开更多
Ag3PO4 microcrystals with highly enhanced visible light photocatalytic activity are prepared by a facile and simple solid state reaction at room temperature. The composition, morphology and optical properties of the a...Ag3PO4 microcrystals with highly enhanced visible light photocatalytic activity are prepared by a facile and simple solid state reaction at room temperature. The composition, morphology and optical properties of the asprepared Ag3PO4 microcrystMs are characterized by x-ray diffraction, scanning electron microscopy and UV-vis diffuse reflectance spectra. The photocatalytie properties of Ag3PO4 are investigated by the degradation of both methylene blue and methyl orange dyes under visible light irradiation. The as-prepared Ag3PO4 microcrystals possess high photocatalytic oxygen production with the rate of 673μmolh-1g-1. Moreover, the as-prepared Ag3PO4 microcrystals show an enhanced photoelectrochemistry performance under irradiation of visible light.展开更多
Discovery of a new superconductor with distinct crystal structure and chemistry often provides great opportunity for further expanding superconductor material base,and also leads to better understanding of superconduc...Discovery of a new superconductor with distinct crystal structure and chemistry often provides great opportunity for further expanding superconductor material base,and also leads to better understanding of superconductivity mechanisms.Here,we report the discovery of superconductivity in a new intermetallic oxide Hf_(3)Pt_Ge_(2)O synthesized through a solid-state reaction.The Hf_(3)Pt_Ge_(2)O crystallizes in a cubic structure(space group Fm-3 m)with a lattice constant of a=1.241 nm,whose stoichiometry and atomic structure are determined by electron microscopy and x-ray diffraction techniques.The superconductivity at 4.1 K and type-II superconducting nature are evidenced by the electrical resistivity,magnetic susceptibility,and specific heat measurements.The intermetallic oxide Hf_(3)Pt_Ge_(2)O system demonstrates an intriguing structural feature that foreign oxygen atoms can be accommodated in the interstitial sites of the ternary intermetallic framework.We also successfully synthesized a series of Hf_(3)Pt_Ge_(2)O1+δ(-0.25≤δ≤0.5),and found theδ-dependent superconducting transition temperature Tc.The atomic structure and the electronic structure are also substantiated by first-principles calculations.Our results present an entirely new family of superconductors with distinct structural and chemical characteristics,and could attract research interest in further finding new superconductors and exploring novel physics pertaining to the 5 d-electron in these intermetallic compound systems.展开更多
Plate-shaped ZnO nanocrystals are prepared by a facile and environmentally friendly molten sMt method, in which ZnD（CO3）2（OH）6 nanorods are first synthesized via a facile one-step, solid-state reaction route at ro...Plate-shaped ZnO nanocrystals are prepared by a facile and environmentally friendly molten sMt method, in which ZnD（CO3）2（OH）6 nanorods are first synthesized via a facile one-step, solid-state reaction route at room temperature and then decomposed in NaCI flux. Photoluminescence property demonstrates that the as-prepared plate-shaped ZnO nanocrystals exhibit a strong blue emission centered at about 483nm. Raman scattering spectrum reveals that the as-prepared plate-shaped ZnO nanocrystals have the oxygen deficiency, which can be confirmed by the appearance of oxygen-deficiency-related vibrationM mode at 583 cm-1 in the Raman spectrum. The oxygen deficiency existing in the plate-shaped ZnO nanocrystals results in the formation of the oxygen vacancy, which is most likely responsible for the strong blue emission of the plate-shaped ZnO nanocrystals. These new plate-shaped ZnO nanocrystals with strong blue emission are expected to show considerable potential applications in luminescence, lasing and optoelectronic devices.展开更多
基金Project supported by the National Basic Research Program of China(Grant Nos.2011CBA00101,2010CB923002,2012CB821404,and 2011CB921703)the National Natural Science Foundation of China(Grant Nos.11190022,11274368,and 51272277)the Funds from the Chinese Academy of Sciences
文摘Transmission electron microscopy （TEM） study of SrPt2As2 reveals two incommensurate modulations appearing in the charge-density-wave （CDW） state below TCDW ≈ 470 K. These two structural modulations can be well explained in terms of condensations of two-coupled phonon modes with wave vectors of q1=0.62a＊ on the a＊-b＊ plane and q2 = 0.23a＊ on the a＊-c＊ plane. The atomic displacements occur along the b-axis direction for q1 and along the c-axis direction for q2, respectively. Moreover, the correlation between ql and q2 can be generally written as q1 = （q2 ＋ a＊）/2 in the CDW state, suggesting the presence of essential coupling between q1 and q2. A small fraction of Ir doping on the Pt site in Sr（Pt1-xIrx）2As2 （x ≤ 0.06） could moderately change these CDW modulations and also affect their superconductivities.
基金Project supported by the National Natural Science Foundation of China (Grant No.10705056)the "985 Project" (Grant No.98507-010009)+2 种基金the "211 Project" of Ministry of Education of Chinathe Pilot Project of Comprehensive Reform for the Specialty of Applied Physics of Minzu University of Chinathe Undergraduate Research Training Program of Minzu University of China (Grant Nos.GCCX 2012110007 and 2012110008)
文摘Multifunctional TiO2/Ag composite nanowires are fabricated with a hydrothermal method by precipitating Ag nanoparticles （NPs） on the surfaces of TiO2 nanowires. This hierarchical one-dimensional （1D） nanostructure can be used as a surface enhanced Raman scattering （SERS） substrate with high sensitivity, for detecting the rhodamine 6G （R6G） in a wide range of low concentrations （from 1 × 10 6 M to 1 × 10-12 M）. In addition, the substrate can be self-cleaned under the irradiation of ultraviolet （UV） light due to the superior photocatalytic capacity of the TiO2/Ag composite nanostructure, making the recycled use of SERS substrates closer to reality. With both the evident SERS performance and high efficiency of photocatalytic capacity, such TiOz/Ag composite nanowires demonstrate considerable potential in the chemical sensing of organic pollutants.
基金supported by the National Natural Science Foundation of China(Grant Nos.10874227,11074292,and 10904166)
文摘Snperconductivities and structural properties of Ti-Zr-Ta ternary alloys are extensively investigated. The TiZrTa sample has a cubic structure （β-phase） and shows a sharp superconducting transition at a critical temperature （To） of about 7.3 K. In addition, two series of Ti-Zr-Ta alloys, with nominal compositions of Ti65-xZr35Tax and TixZr65-xTa35 respectively,are prepared, and their superconductivities and crystal structures change regularly with the chemical composition. Our experimental study also indicates that the annealing processing of this kind of material can cause the transition temperature to increase and the highest Tc is observed to be about 8.3 K in annealed samples.
基金Supported by the Beijing Higher Education Young Elite Teacher Project under Grant No YETP1297the Fundamental Research Funds for the Central Universities under Grant No 2014MDLXYZY05+1 种基金the Undergraduate Innovative Test Program of China under Grant Nos GCCX2015110009 and BEIJ2015110024the National Natural Science Foundation of China under Grant Nos11074312 and 11374377
文摘Ag3PO4 microcrystals with highly enhanced visible light photocatalytic activity are prepared by a facile and simple solid state reaction at room temperature. The composition, morphology and optical properties of the asprepared Ag3PO4 microcrystMs are characterized by x-ray diffraction, scanning electron microscopy and UV-vis diffuse reflectance spectra. The photocatalytie properties of Ag3PO4 are investigated by the degradation of both methylene blue and methyl orange dyes under visible light irradiation. The as-prepared Ag3PO4 microcrystals possess high photocatalytic oxygen production with the rate of 673μmolh-1g-1. Moreover, the as-prepared Ag3PO4 microcrystals show an enhanced photoelectrochemistry performance under irradiation of visible light.
基金the National Key Research and Development Program of China(Grant Nos.2016YFA0300303,2017YFA0504703,2017YFA03029042017YFA0303000)+4 种基金the National Basic Research Program of China(Grant No.2015CB921304)the National Natural Science Foundation of China(Grant Nos.11774391,11774403,and 11804381)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant Nos.XDB25000000and XDB07020000)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(Grant No.ZDKYYQ20170002)the China Postdoctoral Science Foundation(Grant No.BX20180351)。
文摘Discovery of a new superconductor with distinct crystal structure and chemistry often provides great opportunity for further expanding superconductor material base,and also leads to better understanding of superconductivity mechanisms.Here,we report the discovery of superconductivity in a new intermetallic oxide Hf_(3)Pt_Ge_(2)O synthesized through a solid-state reaction.The Hf_(3)Pt_Ge_(2)O crystallizes in a cubic structure(space group Fm-3 m)with a lattice constant of a=1.241 nm,whose stoichiometry and atomic structure are determined by electron microscopy and x-ray diffraction techniques.The superconductivity at 4.1 K and type-II superconducting nature are evidenced by the electrical resistivity,magnetic susceptibility,and specific heat measurements.The intermetallic oxide Hf_(3)Pt_Ge_(2)O system demonstrates an intriguing structural feature that foreign oxygen atoms can be accommodated in the interstitial sites of the ternary intermetallic framework.We also successfully synthesized a series of Hf_(3)Pt_Ge_(2)O1+δ(-0.25≤δ≤0.5),and found theδ-dependent superconducting transition temperature Tc.The atomic structure and the electronic structure are also substantiated by first-principles calculations.Our results present an entirely new family of superconductors with distinct structural and chemical characteristics,and could attract research interest in further finding new superconductors and exploring novel physics pertaining to the 5 d-electron in these intermetallic compound systems.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11074312 and 11374377, and the Undergrad- uate Innovative Test Program of China under Grant Nos GCCX2012110012 and GCCX2012110009.
文摘Plate-shaped ZnO nanocrystals are prepared by a facile and environmentally friendly molten sMt method, in which ZnD（CO3）2（OH）6 nanorods are first synthesized via a facile one-step, solid-state reaction route at room temperature and then decomposed in NaCI flux. Photoluminescence property demonstrates that the as-prepared plate-shaped ZnO nanocrystals exhibit a strong blue emission centered at about 483nm. Raman scattering spectrum reveals that the as-prepared plate-shaped ZnO nanocrystals have the oxygen deficiency, which can be confirmed by the appearance of oxygen-deficiency-related vibrationM mode at 583 cm-1 in the Raman spectrum. The oxygen deficiency existing in the plate-shaped ZnO nanocrystals results in the formation of the oxygen vacancy, which is most likely responsible for the strong blue emission of the plate-shaped ZnO nanocrystals. These new plate-shaped ZnO nanocrystals with strong blue emission are expected to show considerable potential applications in luminescence, lasing and optoelectronic devices.
