Annealing Behaviour of Fe-C-N Nanopowder: Formation of Iron/Graphite Core-Shell Structured Nanoparticles

2005 ◽  
Vol 482 ◽  
pp. 187-190 ◽  
Author(s):  
B. David ◽  
N. Pizúrová ◽  
O. Schneeweiss ◽  
Petr Bezdička ◽  
J. Filip ◽  
...  
Keyword(s):  
Gas Phase ◽  
Iron Nanoparticles ◽  
Magnetic Measurements ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Core ◽  
Graphite Nanoparticles ◽  
The Mean ◽  
Core Shell Structure

We are reporting the core-shell structured iron/graphite nanoparticles formed by annealing of a nanopowder. The original Fe-C-N based nanopowder has been synthesized by the laser pyrolysis of gas phase reactants. TEM, XRD, Raman spectroscopy, Mössbauer spectroscopy and magnetic measurements were used for its characterization. Nanopowder was heated up to 800°C at ~ 1 Pa vacuum. Presence of iron nanoparticles with the mean diameter of 40 nm in the annealed state of the nanopowder was confirmed from the width of α-Fe X-ray diffraction lines and their core-shell structure was observed under TEM.

Influence of Nanoparticle Size on Strain at the Core-Shell Interface

2015 ◽  
Vol 662 ◽  
pp. 217-220 ◽  
Author(s):  
Ondrej Milkovič ◽  
Jana Michaliková ◽  
Jozef Bednarčík ◽  
Štefan Michalik
Keyword(s):  
Solid State ◽  
High Energy ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Core ◽  
Structure Of Nanoparticles ◽  
Fe Nanoparticles ◽  
Hall Method ◽  
Core Shell Structure

This work deals with the strain at the core-shell interface of Fe nanoparticles. Series of Fe nanoparticles with various mean diameters were prepared by precipitation in solid state in binary Cu-Fe alloy. Further, nanoparticles were isolated by dissolution of Cu matrix. High-energy X-ray diffraction (XRD) was used to probe structure of nanoparticles. XRD measurements suggest presence of the core-shell structure, where core and shell of the nanoparticles are formed of α-Fe and CuFe2O4 phase, respectively. Strains in core and shell were estimated as a function of nanoparticles size by Williamson-Hall method.

Controlled Synthesis of Core-Shell Structure SiO2 /NaGdF4:Eu3+ Magnetic and Optical Bifunctional Composite

2014 ◽  
Vol 936 ◽  
pp. 359-363
Author(s):  
Yan Li Wu ◽  
Min Liao ◽  
Hai Xin Ding ◽  
Ru Chun Yang ◽  
Dan Dan Xiong ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Shell Structure ◽  
Photo Luminescence ◽  
Core Shell ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Core ◽  
Core Shell Structure ◽  
Shell Composite

The SiO2/NaGdF4:Eu3+ core/shell composite was prepared by a template-mediated method, making monodispersed SiO2 as core and NaGdF4:Eu colloids as shell, the morphology and the core-shell structure of the resulting particles were analyzed by SEM,X-ray diffraction, and the photo-luminescence and magnetic properties of the microspheres were investigated too. The results shows the composite have great potential to be used as homogeneous magnetic/optical bifunctional material.

Synthesis and Micro-Wave Absorption Properties of BiFeO3 Coated Fe Nanocapsules

2013 ◽  
Vol 712-715 ◽  
pp. 229-232 ◽  
Author(s):  
Gui Mei Shi ◽  
Da Wei Lu ◽  
Yan Zhang
Keyword(s):  
Reflection Loss ◽  
Photoelectron Spectrum ◽  
Core Shell ◽  
Absorber Thickness ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
X Ray ◽  
The Core ◽  
Core Shell Structure ◽  
Thickness Layer

BiFeO3coated ferromagnetic Fe nanocapsules is synthesized by arc-discharging method. Typical HRTEM images show that the nanocapsules form in a core-shell structure. X-ray photoelectron spectrum (XPS) and X-ray diffraction (XRD) reveal that the core is ferromagnetic Fe, while the shell is BiFeO3/Bi2Fe4O9.The reflection loss R of less than -10 dB was obtained for the whole frequency within the 2-18GHz range by choosing an appropriate layer thickness between 1.0mm and 7.0mm. An optimal reflection loss of -21.5 dB was reached at 10.6 GHz with an absorber thickness of 2.0mm. It is worth noticing that the BiFeO3coated Fe nanocapsules have two absorption peaks below -10 dB at each thickness layer ranging from 4.0nm to 7.0nm, which means the composites nanocapsules absorber simultaneously are able to absorb microwaves in different band of several GHz.

The Microemulsion Method for Preparing TiO2 Coated SiO2 Core-Shell Particles

2014 ◽  
Vol 602-603 ◽  
pp. 59-62
Author(s):  
Jing Xie ◽  
Le Fu Mei ◽  
Li Bing Liao ◽  
Guo Cheng Lv ◽  
Zhi Guo Xia ◽  
...  
Keyword(s):  
Shell Structure ◽  
Sintering Temperature ◽  
Phase Changes ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Core ◽  
Core Shell Structure ◽  
Shell Particles ◽  
Morphology Changes

In this paper, the monodisperse TiO2 particles and TiO2 coated SiO2 core-shell particles were prepared by the method of microemulsion, and the phase and morphology of TiO2 and TiO2 coated SiO2 core-shell structure particles were analyzed by using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). At the same time, the phase changes and morphology changes of the two different kinds of structural particles as the changes of sintering temperature were compared. The results show that when the TiO2 particles were prepared by the method of microemulsion, the content of anatase TiO2 decreased gradually and the rutile TiO2 increased gradually as the sintering temperature increases from 550 °C to 650 °C; the core-shell particles of TiO2 coated SiO2 prepared were anatase when the sintering temperature increases from 600 °C to 800 °C; all of the particles size were about 1μm, the monodispersity of the particles were optimal and the particles were coated evenly, smoothly. Keywords: TiO2; SiO2; core-shell structure

Preparation of Amorphous Calcium Phosphate/Triclcium Silicate Composite Powders

2009 ◽  
Vol 79-82 ◽  
pp. 1643-1646 ◽  
Author(s):  
Qing Lin ◽  
Yan Bao Li ◽  
Xiang Hui Lan ◽  
Chun Hua Lu ◽  
Zhong Zi Xu
Keyword(s):  
Calcium Phosphate ◽  
Shell Structure ◽  
Amorphous Calcium Phosphate ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Composite Powders ◽  
X Ray ◽  
Core Shell Structure

The amorphous calcium phosphate (ACP)/tricalcium silicate (Ca3SiO5, C3S) composite powders were synthesized in this paper. The exothermal behavior of C3S determined by isothermal conduction calorimetry indicated that the ACP could be synthesis by chemical precipitation method during the induction period (stage II) of C3S. The composite powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results indicated that nanosized ACP particles deposited on the surface of C3S particles to form core-shell structure at pH=10.5, and the nCa/nP of ACP could be controlled between 1.0 and 1.5. The core-shell structure is stable after sintered at 500 oC for 3 h to remove the β-cyclodextrin (β-CD). As compared with the irregular C3S particles (1~5 μm), the composite powders particles are spherical with a diameter of 40~150 μm. Therefore, to obtain the smaller size of composite powders, it is expected to avoid the aggregate of C3S particles in the aqueous solution by addition of dispersant. As compared with C3S, the composite powders may contribute better injectability, strength and biocompatibility.

One-pot microwave assisted approach for synthesis of CdSe/CdS core-shell quantum dots (QDs) and investigating optical properties

2016 ◽  
Vol 30 (07) ◽  
pp. 1650074 ◽  
Author(s):  
M. Molaei ◽  
F. Salari Bardsiri ◽  
A. R. Bahador ◽  
M. Karimipour
Keyword(s):  
Core Shell ◽  
Heat Sensitivity ◽  
X Ray Diffraction ◽  
Cdse Qds ◽  
One Pot ◽  
X Ray ◽  
Microwave Assisted ◽  
Transmission Electron ◽  
Core Shell Structure ◽  
Microwave Assisted Method

In this work, CdSe QDs were synthesized using a microwave assisted method and chemical reaction between NaHSe, CdSO4 at the presence of TGA as capping molecule. Thereafter without CdSe extraction, CdS shell was grown subsequently around CdSe cores by a reaction based on the heat sensitivity of Na2S2O3 dissociation. Synthesized QDs were characterized by means of X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), UV–Vis and photoluminescence (PL) spectroscopy. All of these analyzes confirmed formation of CdSe QDs and successfully growth of CdS shell on surface of CdSe to forming CdSe/CdS core-shell structure.

Study the Effect of HAp Content in PLA/HAp Microsphere on the Efficiency of Drug (Clindamycin) Loading Process

2013 ◽  
Vol 834-836 ◽  
pp. 559-562 ◽  
Author(s):  
Juntima Pradid ◽  
Wirunya Keawwattana ◽  
Siree Tangbunsuk
Keyword(s):  
Electron Microscopy ◽  
Thermal Process ◽  
High Performance ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ultrasound Field ◽  
Sample Characterization ◽  
Core Shell Structure ◽  
Scanning Electron

An ultrasound field was applied to obtain Polylactic acid (PLA)/Hydroxyapatite (HAp) biocomposite microspheres with the specific core-shell structure to be applied as a carrier of a drug. The hydroxyapatite was obtained from crocodile bone by thermal process. Sample characterization was achieved by powder X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX) Scanning electron microscopy (SEM) and High Performance Liquid Chromatography (HPLC). As the result, the PLA/HAp loading clindamycin with different polymer-to-ceramic part wt.% ratio (100:0, 90:10, 80:20, and 70:30) showed the agglomeration of sphere-like particles. In addition, the loading efficiency of clindamycin increased with increasing HAp content up to 20%.

scholarly journals In-Situ Synchrotron SAXS and WAXS Investigation on the Deformation of Single and Coaxial Electrospun P(VDF-TrFE)-Based Nanofibers

2021 ◽  
Vol 22 (23) ◽  
pp. 12669
Author(s):  
Yi-Jen Huang ◽  
Yi-Fan Chen ◽  
Po-Han Hsiao ◽  
Tu-Ngoc Lam ◽  
Wen-Ching Ko ◽  
...  
Keyword(s):  
Hierarchical Structures ◽  
Electrospun Nanofibers ◽  
Mechanical Anisotropy ◽  
Core Shell ◽  
Length Scale ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Core ◽  
Nanofiber Alignment

Coaxial core/shell electrospun nanofibers consisting of ferroelectric P(VDF-TrFE) and relaxor ferroelectric P(VDF-TrFE-CTFE) are tailor-made with hierarchical structures to modulate their mechanical properties with respect to their constituents. Compared with two single and the other coaxial membranes prepared in the research, the core/shell-TrFE/CTFE membrane shows a more prominent mechanical anisotropy between revolving direction (RD) and cross direction (CD) associated with improved resistance to tensile stress for the crystallite phase stability and good strength-ductility balance. This is due to the better degree of core/shell-TrFE-CTFE nanofiber alignment and the crystalline/amorphous ratio. The coupling between terpolymer P(VDF-TrFE-CTFE) and copolymer P(VDF-TrFE) is responsible for phase stabilization, comparing the core/shell-TrFE/CTFE with the pristine terpolymer. Moreover, an impressive collective deformation mechanism of a two-length scale in the core/shell composite structure is found. We apply in-situ synchrotron X-ray to resolve the two-length scale simultaneously by using the small-angle X-ray scattering to characterize the nanofibers and the wide-angle X-ray diffraction to identify the phase transformations. Our findings may serve as guidelines for the fabrication of the electrospun nanofibers used as membranes-based electroactive polymers.

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