Morphology of Nanoparticles and Fullerene Blacks Produced in A Carbon Arc

1994 ◽  
Vol 359 ◽  
Author(s):  
John Henry J. Scott ◽  
S. A. Majetich ◽  
S. Derrington
Keyword(s):  
Inner Core ◽  
Crystallographic Structure ◽  
Cathode Deposit ◽  
X Ray ◽  
The Core ◽  
Coated Nanoparticles ◽  
Transmission Electron ◽  
Carbon Coated ◽  
Carbon Arc ◽  
Graphite Rods

ABSTRACTUsing X-ray powder diffraction and transmission electron microscopy we examine the morphology and crystallographic structure of carbon-coated nanoparticles produced in a modified Huffman-Kratschmer carbon arc process. Graphite rods containing Ho were consumed in the arc and soots sampled from both the reactor walls and the inner core of the cathode deposit are compared. The inner core soot displays increased crystallinity and less amorphous carbon than wall-deposited soot, and nanoparticles in the inner core have more graphitic layers in the encapsulating shells, more gaps between the carbon coating and the core, and exhibit a greater degree of facetting than particles harvested from the reactor walls. These differences are interpreted as manifestations of the high temperature post-formation environment of the inner core of the cathode deposit.

Carbon Coated Nanoparticle Composites Synthesized in an RF Plasma Torch

1996 ◽  
Vol 457 ◽  
Author(s):  
John Henry J. Scott ◽  
Sara A. Majetich ◽  
Zafer Turgut ◽  
Michael E. Mchenry ◽  
Maher Boulos
Keyword(s):  
Plasma Torch ◽  
Rf Plasma ◽  
Coated Nanoparticles ◽  
Transmission Electron ◽  
Large Numbers ◽  
Carbon Coated ◽  
Carbon Arc ◽  
A Chain ◽  
Nanoparticle Composites ◽  
Encapsulated Nanoparticles

ABSTRACTFeCo alloy nanoparticles are synthesized in an RF plasma torch reactor and characterized using X-ray powder diffraction (XRD) and transmission electron microscopy (XRD). Bare, uncoated particles exhibit a chain-like agglomeration morphology marked by large ring- and bridge-like structures surrounding open voids. Acetylene was used to generate large numbers of carbon-coated nanoparticles similar to those produced in carbon arc reactors. Conventional TEM of this powder revealed numerous particles below 50 nm in diameter embedded in a carbonaceous matrix. These results establish RF plasma torch processing as a well-characterized, scalable alternative to carbon arc synthesis of encapsulated nanoparticles.

scholarly journals Carbon-coated magnetic particles increase tissue temperatures after laser irradiation

2015 ◽  
Vol 08 (05) ◽  
pp. 1550018 ◽  
Author(s):  
Shupeng Liu ◽  
Na Chen ◽  
Fufei Pang ◽  
Zhengyi Chen ◽  
Tingyun Wang
Keyword(s):  
Laser Irradiation ◽  
Magnetic Particles ◽  
Laser Energy ◽  
Thermal Therapy ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fbg Sensor ◽  
Transmission Electron ◽  
Carbon Coated

Purpose: This work focused on the investigation the hyperthermia performance of the carbon-coated magnetic particles (CCMPs) in laser-induced hyperthermia. Materials and methods: We prepared CCMPs using the organic carbonization method, and then characterized them with transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectrophotometry, vibrating sample magnetometer (VSM) and X-ray diffraction (XRD). In order to evaluate their performance in hyperthermia, the CCMPs were tested in laser-induced thermal therapy (LITT) experiments, in which we employed a fully distributed fiber Bragg grating (FBG) sensor to profile the tissue's dynamic temperature change under laser irradiation in real time. Results: The sizes of prepared CCMPs were about several micrometers, and the LITT results show that the tissue injected with the CCMPs absorbed more laser energy, and its temperature increased faster than the contrast tissue without CCMPs. Conclusions: The CCMPs may be of great help in hyperthermia applications.

Identification of Nanocrystalline Inclusions in Bismuth-Doped Silica Fibers and Preforms

2016 ◽  
Vol 22 (5) ◽  
pp. 987-996 ◽  
Author(s):  
Liudmila D. Iskhakova ◽  
Filipp O. Milovich ◽  
Valery M. Mashinsky ◽  
Alexander S. Zlenko ◽  
Sergey E. Borisovsky ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Room Temperature ◽  
Optical Loss ◽  
Laser Generation ◽  
Dopant Distribution ◽  
X Ray ◽  
The Core ◽  
Silica Fibers ◽  
Transmission Electron ◽  
Bismuth Concentration

AbstractThe nature of nanocrystalline inclusions and dopant distribution in bismuth-doped silicate fibers and preforms are studied by scanning and transmission electron microscopy, and energy and wavelength-dispersive X-ray microanalysis. The core compositions are Bi:SiO2, Bi:Al2O3–SiO2, Bi:GeO2–SiO2, Bi:Al2O3–GeO2–SiO2, and Bi:P2O5–Al2O3–GeO2–SiO2. Nanocrystals of metallic Bi, Bi2O3, SiO2, GeO2, and Bi4(GeO4)3 are observed in these glasses. These inclusions can be the reason for the background optical loss in bismuth-doped optical fibers. The bismuth concentration of 0.0048±0.0006 at% is directly measured in aluminosilicate optical fibers with effective laser generation (slope efficiency of 27% at room temperature).

scholarly journals Finger-Like Carbon-Based Nanostructures Produced by Combustion of Flour-Based Sticks (Spaghetti)

2019 ◽  
Vol 5 (2) ◽  
pp. 21 ◽  
Author(s):  
Frederik Ossler ◽  
Crispin J. D. Hetherington
Keyword(s):  
Electron Microscopy ◽  
Carbon Film ◽  
Tube Formation ◽  
X Ray ◽  
The Core ◽  
Carbon Structures ◽  
Transmission Electron ◽  
Core Components ◽  
Biomass Materials ◽  
Graphene Structures

Biomass is becoming particularly important as a starting material for advanced carbon structures. In this study, we found interesting nanostructures on the surface of burnt spaghetti using scanning electron microscopy, transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX) for analysis. The structures were elongated and finger-like, with evidence that the tubes have shell and core components. The shell was carbon that included amorphous and layered graphene structures. EDX showed enriched potassium and phosphorous in the core and at the tip of the tubes. The results indicate that tube formation depends on phase separation of polar/ionic and nonpolar moieties when water is produced in the biomass from the pyrolysis/combustion. The tube growth is most probably due to the raising pressure of vapor that cannot escape through the carbon film that is formed at the surface of the stick from flame heat. This process resembles glass blowing or volcanic activity, where the carbon acts as the glass or earth’s crust, respectively. These observations suggest that new interesting tubular nanostructures with different properties on the inside and outside can be produced in a relatively simple way, utilizing processes of combustion of starch-rich biomass materials.

Preparation of Fe3O4-Coated Microsilica Composites via Chemical Reduction Method

2013 ◽  
Vol 750-752 ◽  
pp. 1071-1074
Author(s):  
Hui Xia Feng ◽  
Bai Yi Chen ◽  
De Yi Zhang ◽  
Jian Qiang Zhang ◽  
He Ming Luo
Keyword(s):  
Electron Microscope ◽  
Reduction Method ◽  
Chemical Reduction ◽  
Vibrating Sample Magnetometer ◽  
Chemical Reduction Method ◽  
Magnetic Composites ◽  
X Ray ◽  
The Core ◽  
Transmission Electron ◽  
Novel Method

Fe3O4-coated microsilica composites were synthesized by a novel method. The struction like precursor Fe3O4 nanoparticles as the shell and microsillica as the core for the composite has been prepared by chemical reduction method. The Fe3O4-coated microsilica composite presents a saturation magnetization value of 38.03 emu/g, which is sufficient to complete magnetic separation. The synthesized magnetic composites are characterized by X-ray diffractometer (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The results indicated that Fe3O4 nanoparticles successfully coated on microsilica.

Preparation of Carbon-Encapsulated Fe Core-Shell Nanostructures by Confined Arc Plasma

2011 ◽  
Vol 688 ◽  
pp. 245-249 ◽  
Author(s):  
Zhi Qiang Wei ◽  
Xiao Yun Wang ◽  
Hua Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Core Shell ◽  
Arc Plasma ◽  
X Ray ◽  
The Core ◽  
Transmission Electron

Special carbon encapsulated Fe core-shell nanoparticles with a size range of 15–40 nm were successfully prepared via confined arc plasma method. The composition, morphology, microstructure, specific surface area, particle size of the product by this process were characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (XEDS) and BET N2adsorption. The experiment results shown that the carbon encapsulated Fe nanoparticles with clear core-shell structure, the core of the particles is body centered cubic (BCC) structure Fe, and the shell of the particles is disorder carbons. The particle size of the nanocapsules ranges from 15 to 40nm，with an averaged value about 30nm, the particles diameter of the core is about 16nm and the thickness of the shells is about 6-8 nm, and the specific surface area is 24 m2/g.

Oxygen content, microstructure, and superconductivity of YBa2Cu3O7−x

1987 ◽  
Vol 2 (6) ◽  
pp. 743-749 ◽  
Author(s):  
M. P. A. Viegers ◽  
D. M. de Leeuw ◽  
C. A. H. A. Mutsaers ◽  
H. A. M. van Hal ◽  
H. C. A. Smoorenburg ◽  
...  
Keyword(s):  
Single Phase ◽  
Inner Core ◽  
X Ray ◽  
Cell Parameters ◽  
Preparation Conditions ◽  
Transmission Electron ◽  
Quench Temperature ◽  
Orthorhombic Cell ◽  
The Difference ◽  
Individual Grains

The influence of preparation conditions and microstructure on the superconductive properties of single-phase poly-crystalline YBa2Cu3O7−x was investigated by electron probe microanalysis, transmission electron microscopy (TEM), and x-ray powder diffraction as a function of temperature in various ambients supplemented by resistivity and susceptibility measurements. Leaching of Ba was observed when samples were brought in contact with water. The TEM imaging revealed that individual grains have an extremely defect-rich outer shell and an inner core with a domain structure with a and b axes interchanged. The transition temperature Tc was found to decrease with increasing quench temperature in the range 400–900°C. The Tc was observed to be linearly proportional to the difference in the orthorhombic cell parameters (b-a). Further implications are discussed.

Synthesis and Characteristic of NiFe/NiFe2O4 Core-Shell Magnetic Nanocomposite Particles

2012 ◽  
Vol 486 ◽  
pp. 65-69
Author(s):  
Jun Hu ◽  
Ai Min Chen
Keyword(s):  
Structural Evolution ◽  
Treatment Temperature ◽  
Oxide Shell ◽  
Core Shell ◽  
Nanocomposite Particles ◽  
X Ray ◽  
The Core ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Feni Alloy

NiFe/NiFe2O4 core-shell bimagnetic nanocomposite particles were successfully synthesized by colloidal chemical method combined with H2 reduction. The whole structural evolution process has been well studied through analysis of X-ray diffraction patterns and Infrared spectra. It has been found that FeNi alloy concentrated in the ferrite phase. The core/shell structure, a FeNi alloy core surrounded by NiFe2O4 spinel oxide shell were verified by X-ray powder diffraction (XRD), fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The influence of post H2 heat treatment temperature on nanoparticles was investigated. The core-shell NiFe/ NiFe2O4 nanoparticles was about 100 nm after reduced at 727 K, The powders exhibited paramagnetic properties and the magnetization was 29.9 emu·g-1.

scholarly journals Synthesis and high-resolution structural and chemical analysis of iron-manganese-oxide core-shell nanocubes

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Aladin Ullrich ◽  
Mohammad Mostafizar Rahman ◽  
Paolo Longo ◽  
Siegfried Horn
Keyword(s):  
High Resolution ◽  
Core Shell ◽  
Bright Field ◽  
X Ray ◽  
The Core ◽  
Transmission Electron ◽  
High Boiling Solvent ◽  
Iron Manganese ◽  
Electron Energy Loss ◽  
Shell Region

AbstractWe have investigated the structure and chemical composition of nanoparticles synthesized by thermal decomposition of a mixture of iron oleate and manganese oleate in a high-boiling solvent in the presence of Na-oleate and oleic acid as surfactants by analytical transmission electron microscopy (TEM). The particles appear core-shell like in bright field TEM images. Higher spatial resolution TEM (HRTEM) analysis reveals a FeO/MnO like structure in the core and a spinel like structure in the shell. With high-resolution analytical methods like energy dispersive x-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS), the distribution of the metals Mn and Fe was investigated. Differences in the oxidation state of these metals were found between the core and the shell region. The presence of sodium from the used surfactant (Na-oleate) on the surface of the particles has been proved.

scholarly journals Luminescence Nanothermometry Based on Pr3+ : LaF3 Single Core and Pr3+ : LaF3/LaF3 Core/Shell Nanoparticles

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
M. S. Pudovkin ◽  
D. A. Koryakovtseva ◽  
E. V. Lukinova ◽  
S. L. Korableva ◽  
R. Sh. Khusnutdinova ◽  
...  
Keyword(s):  
Coherent Scattering ◽  
Core Shell ◽  
Fluorescence Intensity Ratio ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
X Ray ◽  
The Core ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Core Shell Nanoparticles

Core Pr3+ : LaF3 (CPr = 1%) plate-like nanoparticles (nanoplates), core/shell Pr3+ : LaF3 (CPr = 1%)/LaF3 nanoplates, core Pr3+ : LaF3 (CPr = 1%) sphere-like nanoparticles (nanospheres), and core/shell Pr3+ : LaF3 (CPr = 1%)/LaF3 nanospheres were synthesized via the coprecipitation method of synthesis. The nanoparticles (NPs) were characterized by means of transmission electron microscopy, X-ray diffraction, and optical spectroscopy. The formation of the shell was proved by detecting the increase in physical sizes, sizes of coherent scattering regions, and luminescence lifetimes of core/shell NPs comparing with single core NPs. The average physical sizes of core nanoplates, core/shell nanoplates, core nanospheres, and core/shell nanospheres were 62.2 ± 0.9, 74.7 ± 1.2, 13.8 ± 0.9 and 22.0 ± 1.2 nm, respectively. The formation of the NP shell led to increasing of effective luminescence lifetime τeff of the 3P0 state of Pr3+ ions for the core nanoplates, core/shell nanoplates, core nanospheres, and core/shell nanospheres the values of τeff were 2.3, 3.6, 3.2, and 4.7 μsec, respectively (at 300 K). The values of absolute sensitivity Sa for fluorescence intensity ratio (FIR) thermometry was 0.01 K−1 at 300 K for all the samples. The FIR sensitivity can be attributed to the fact that 3P1 and 3P0 states share their electronic populations according to the Boltzmann process. The values of Sa for lifetime thermometry for core nanoplates, core/shell nanoplates, core nanospheres, and core/shell nanospheres were (36.4 ± 3.1) · 10−4, (70.7 ± 5.9) · 10−4, (40.7 ± 2.6) · 10−4, and (68.8 ± 2.4) · 10−4 K−1, respectively.

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