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8 results on '"Weiguo Chu"'

2. Large magnetic moment at sheared ends of single-walled carbon nanotubes

Author

Lianfeng Sun, Ya-Yun Liu, Xiannian Chi, Tingting Hao, Pei Wu, Ya Deng, Changzhi Gu, Weiguo Chu, Siyu Liu, Junjie Li, Jean Pierre Nshimiyimana, Zhisheng Peng, Xiao Hu, Jian Zhang, Gongtang Wang, and Zhong Zhang

Subjects
Materials science, Condensed matter physics, Magnetic moment, law, 0103 physical sciences, General Physics and Astronomy, 02 engineering and technology, Carbon nanotube, 021001 nanoscience & nanotechnology, 010306 general physics, 0210 nano-technology, 01 natural sciences, law.invention
Published
2018

3. Highly sensitive and stable SERS probes of alternately deposited Ag and Au layers on 3D SiO 2 nanogrids for detection of trace mercury ions

Author

Hanfu Wang, Fengliang Dong, Attia Falak, Yi Tian, Peipei Chen, Yan Lanqin, Weiguo Chu, Xianfeng Zhang, and Lianfeng Sun

Subjects
Materials science, Inorganic chemistry, General Physics and Astronomy, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Mercury (element), Highly sensitive, Ion, chemistry, 0210 nano-technology
Published
2018

4. Structure dependence of magnetic properties of Pr5Si2Ge2

Author

Gui-Chuan Liu, X. M. Feng, G. H. Rao, Junjun Liang, Hui Yang, Weifang Liu, Weiguo Chu, and Zhong-Can Ou-Yang

Subjects
Tetragonal crystal system, Crystallography, Magnetization, Chemical bond, Condensed matter physics, Chemistry, Electrical resistivity and conductivity, Curie temperature, General Materials Science, Crystal structure, Condensed Matter Physics, Powder diffraction, Monoclinic crystal system
Abstract

The crystal structure and magnetic and electronic transport properties of the ternary intermediate compound Pr5Si2Ge2 were investigated by means of x-ray powder diffraction, magnetic and electrical resistance measurements. The compound has two polymorphs: alpha-Pr5Si2Ge2 crystallizing in a monoclinic structure with space group P112(1)/a, for the as-cast sample, and alpha-Pr5Si2Ge2 crystallizing in a tetragonal structure with space group P4(1)2(1)2, for. the sample annealed at 1273 K. The average interatomic distances of magnetic Pr atoms and the amounts of covalent (Si, Ge)-(Si, Ge) bond pairs in these two phases are different, which may be, responsible for their different magnetic properties. The Curie temperatures T-C of alpha-Pr5Si2Ge2 and beta-Pr5Si2Ge2 are 38 and 50 K, respectively. An irreversibility between zero-field-cooling and field-cooling magnetization curves is observed. The zero-field resistance of these two phases exhibits an anomaly near T-C. On the basis of the results of magnetic and electrical resistance measurements, it is inferred that both of these phases exhibit spin-glass-like behaviour. The magnetic properties and structure dependence of the Pr5Si2Ge2 can be elucidated well using the Ruderman-Kittel-Kasuya-Yosida model.

Published
2002

5. Crystal structure and magnetic properties of Gd3Fe28Re

Author

H.F. Yang, Junjun Liang, Weiguo Chu, G.H. Rao, and Guo-Tian Liu

Subjects
Crystallography, Magnetization, Chemistry, Rietveld refinement, Intermetallic, Curie temperature, General Materials Science, Crystal structure, Condensed Matter Physics, Magnetocrystalline anisotropy, Saturation (magnetic), Monoclinic crystal system
Abstract

The structure and magnetic properties of a ternary intermetallic compound Gd3Fe28Re stabilized by Re in the sixth period has been investigated by means of XRD analysis and magnetic measurement. The compound crystallizes in the monoclinic Nd3(Fe,Ti)29-type structure with space group A2/m. The lattice parameters are a = 10.5778(1) A, b = 8.5317(1) A, c = 9.6945(2) A, and β = 96.85(1)°. The preferential occupancy of Re over the 4g, 4i3 and 4i4 crystallographic sites were determined successfully by Rietveld refinement of XRD data, which is basically attributed to the effect of size. The compound exhibits planar magnetocrystalline anisotropy perpendicular to the [204] direction. The Curie temperature TC, the saturation moment MS and the magnetocrystalline anisotropy field HA are derived to be 467 K, 35.1 µB f.u.-1 and 69.4 kOe, respectively.

Published
2001

6. InN/In2O3 peapod nanostructures and conformal conversion templated from InN counterparts via thermal oxidation

Author

Jingbo Li, Shudong Luo, Jun Shen, Zengxing Zhang, Richeng Yu, Lide Yao, Weiguo Chu, Sishen Xie, Jianhong Yi, and Weiya Zhou

Subjects
Thermal oxidation, Thermogravimetric analysis, Materials science, Nanostructure, Mechanical Engineering, Composite number, Nanowire, Shell (structure), Bioengineering, Nanotechnology, General Chemistry, Nitride, Chemical engineering, Mechanics of Materials, Oxidizing agent, General Materials Science, Electrical and Electronic Engineering
Abstract

One-dimensional InN/In2O3 peapod nanostructures were fabricated by thermally oxidizing InN nanowires under controlled conditions based on differential thermogravimetric analysis. With respect to the InN core/In2O3 shell composite material, the preferred crystal orientation of InN [ 0002]/In2O3 [ 222] is maintained during the oxidation process. Further oxidation of the composite materials results in the formation of In2O3 nanowires or nanobelts which exhibit geometrical shape and size similar to those of the original InN counterparts. The present work indicates that thermal oxidation of III nitrides promises an easy and controllable approach to fabricating special structures such as composite, even complex architecture via conformal conversion.

Published
2007

7. A thin film thermoelectric device fabricated by a self-aligned shadow mask method.

Author

Fanglong Yang, Shuqi Zheng, Hanfu Wang, Weiguo Chu, and Yuhua Dong

Subjects
THERMOELECTRIC materials, THIN films, EVAPORATION (Chemistry), ELECTRIC conductivity, SUBSTRATES (Materials science)
Abstract

A planar thermoelectric device with 20 pairs of Sb2Te3 and Bi2Te3 thin-film legs was fabricated by using a facile self-aligned shadow mask method in combination with a thermal evaporation process. Effects of substrate temperature during the evaporation process on the Seebeck coefficient and electrical conductivity of the thin films have been investigated. The maximum Seebeck coefficient was found to be 158 µV K−1 for the Sb2Te3 film produced at 260 °C and  −148 µV K−1 for the Bi2Te3 film produced at 230 °C. The device was fabricated on a glass substrate under the above optimal conditions. At a temperature difference of 90 K, it demonstrated an open-circuit voltage of more than 0.5 V (which was equivalent of a sensitivity of 5.40 mV K−1) and a maximum output power of 1.105 µW. [ABSTRACT FROM AUTHOR]

Published
2017
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8. Fabrication of single-crystal silicon nanotubes with sub-10 nm walls using cryogenic inductively coupled plasma reactive ion etching.

Author

Zhiqin Li, Yiqin Chen, Xupeng Zhu, Mengjie Zheng, Fengliang Dong, Peipei Chen, Lihua Xu, Weiguo Chu, and Huigao Duan

Subjects
NANOFABRICATION, NANOMANUFACTURING, NANOSTRUCTURED materials, SILICONES, PHOTOVOLTAIC power generation
Abstract

Single-crystal silicon nanostructures have attracted much attention in recent years due in part to their unique optical properties. In this work, we demonstrate direct fabrication of single-crystal silicon nanotubes with sub-10 nm walls which show low reflectivity. The fabrication was based on a cryogenic inductively coupled plasma reactive ion etching process using high-resolution hydrogen silsesquioxane nanostructures as the hard mask. Two main etching parameters including substrate low-frequency power and SF6/O2 flow rate ratio were investigated to determine the etching mechanism in the process. With optimized etching parameters, high-aspect-ratio silicon nanotubes with smooth and vertical sub-10 nm walls were fabricated. Compared to commonly-used antireflection silicon nanopillars with the same feature size, the densely packed silicon nanotubes possessed a lower reflectivity, implying possible potential applications of silicon nanotubes in photovoltaics. [ABSTRACT FROM AUTHOR]

Published
2016
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