Technical Study on Preparation of Co/C Composite Nanofibers via Electrospinning

2019 ◽  
Vol 944 ◽  
pp. 666-670
Author(s):  
Sa Zhang ◽  
Jian Jiang Wang ◽  
Fang Zhao
Keyword(s):  
Composite Nanofibers ◽  
Cobalt Acetate ◽  
Organic Salt ◽  
Face Centered Cubic ◽  
Composite Fibers ◽  
Fiber Morphology ◽  
Preparation Technology ◽  
Technical Study ◽  
Face Centered ◽  
The Ideal

Co/C composite nanofibers are prepared through electrospinning. Effect of salt, Spinning humidity, receiving equipment and heat treatment on the formation, morphology and structure of composite fibers were investigated. The morphology of composite fibers was observed by scanning electron microscopy (SEM).It was found out that when the ambient humidity was high, the nanofibers were agglomerated into fiber bundles. When the roller receiving equipment was used, ordered nanofibers can be obtained. Only cobalt acetate-doped composite nanofibers maintained intact fiber morphology after pre-oxidation and carbonization. And Co2+ was completely reduced to face-centered cubic structured Co nanoparticle. The ideal preparation technology is as follows: the humidity at 30% or less, doping with organic salt of cobalt acetate.

A neutron diffraction study on a typical highly defective ceria–yttria solid solution

2002 ◽  
Vol 17 (4) ◽  
pp. 278-280 ◽  
Author(s):  
Keka R. Chakraborty ◽  
S. V. Chavan ◽  
A. K. Tyagi
Keyword(s):  
Solid Solution ◽  
Diffraction Study ◽  
Room Temperature ◽  
Fluorite Structure ◽  
Neutron Diffraction Study ◽  
Neutron Powder Diffraction ◽  
Face Centered Cubic ◽  
Aliovalent Substitution ◽  
Face Centered ◽  
The Ideal

It was seen during the phase relation studies on the CeO2–YO1.5 system that the ceria is able to accommodate a large anion deficiency caused by aliovalent substitution. A neutron powder diffraction study has been carried out at room temperature for the titled solid solution, Ce1−xYxO2−x/2 with x=0.32, which is an anion-deficient variant of the ideal fluorite structure. The structure has been found to be face centered cubic. No superlattice reflections have been observed indicating that the vacancies occupy the random positions in this highly defective solid solution. The bond distances and angles are also being reported.

scholarly journals Preparation and Characterization of porous Carbon/Nickel Nanofibers for Supercapacitor

2013 ◽  
Vol 8 (4) ◽  
pp. 155892501300800 ◽  
Author(s):  
Dawei Gao ◽  
Lili Wang ◽  
Xin Xia ◽  
Hui Qiao ◽  
Yibing Cai ◽  
...  
Keyword(s):  
Carbon Nanofibers ◽  
Porous Carbon ◽  
Composite Nanofibers ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Nickel Particles ◽  
The Face ◽  
Embedded Particles ◽  
Face Centered

Two polymer solutions of polyacrylonitrile, polyvinyl pyrrolidone, and Ni(CH3COOH)2 in dimethylformamide were electrospun into ternary composite nanofibers, followed by stabilization and carbonization processes to obtain porous carbon/nickel composite nanofibers with diameters of 100–200 nm. The study revealed that carbon/nickel composite nanofibers were successfully prepared, which allowed nickel particles with diameters of 20–70 nm to be uniformly distributed in the carbon nanofibers. It was also observed that the fibrous structures with particles embedded formed and the fibers broke into shorter fibers after sintering. X-ray diffraction indicated that embedded particles crystallized with the face centered cubic structure. The Brunauer-Emmett-Teller analysis revealed that carbon/nickel composite nanofibers with meso-pores possessed larger specific surface area than that of carbon nanofibers. The specific capacitance of the composite nanofiber electrode was as high as 103.8 F/g and showed stable cyclicity (73.8%).

Preparation and Characterization of Porous Carbon/Nickle Nanofibers by Electrospinning

2013 ◽  
Vol 853 ◽  
pp. 101-104
Author(s):  
Da Wei Gao ◽  
Qu Fu Wei ◽  
Chun Xia Wang ◽  
Guo Liang Liu ◽  
Xue Mei He ◽  
...  
Keyword(s):  
Carbon Nanofibers ◽  
Porous Carbon ◽  
Composite Nanofibers ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
Bet Analysis ◽  
The Face ◽  
Fibrous Morphology ◽  
Face Centered

By employing the electrospinning technique and subsequent carbonization processes, porous carbon/nickle (C/Ni) composite nanofibers with diameters of 100-200 nm were successfully prepared. Two polymer solutions of polyacrylonitrile (PAN), polyvinyl pyrrolidone (PVP), and Ni (CH3COOH)2(Ni (OAc)2) were used as C/Ni composite nanofiber precursors. The study revealed that C/Ni composite nanofibers were successfully prepared and nickle particles with diameters of 20-70 nm were uniformly scattered in the carbon nanofibers. It was also observed that the fiber with clear fibrous morphology with particles broke into shorter fibers after sinter. X-ray diffraction (XRD) showed that these particles crystallized with the face centered cubic (FCC) structure. The Brunauer-Emmett-Teller (BET) analysis indicated that C/Ni composites nanofibers with meso-pores possessed larger specific surface area than that of carbon nanofibers.

High photoelectric PPV/PVA/Ag composite nanofibers by co-electrospinning

2015 ◽  
Vol 35 (7) ◽  
pp. 689-697 ◽  
Author(s):  
Yang Gao ◽  
Zhiyao Sun ◽  
Liguo Sun ◽  
Cheng Wang ◽  
Shuhong Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Composite Nanofibers ◽  
Average Diameter ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Photoelectric Properties ◽  
Transmission Electron ◽  
Face Centered ◽  
Xrd Patterns

Abstract Poly(phenylene vinylene)/polyvinyl alcohol/Ag (PPV/PVA/Ag) composite nanofibers with excellent photoelectric properties were prepared by coaxial electrospinning using PPV/PVA as the shell and Ag nanoparticles (NPs) as the core, Ag NPs aqueous solution was prepared by the reduction method. The results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that Ag NPs are of a face-centered cubic structure, with an average diameter of 46 nm and the composite nanofibers have uniform and continuous morphology. With increasing Ag content, the diameters of the composite nanofibers decreased from 653 nm to 250 nm. The X-ray diffraction (XRD) patterns verified that in the composite nanofibers, the Ag NPs are not transformed. In the photoluminescence spectra, the PPV/PVA/Ag composite nanofibers presented red-shift compared with PPV/PVA nanofibers. Under illumination, the as-prepared PPV/PVA/Ag composite nanofibers exhibited relatively high photocurrent intensity.

The effect of transverse loading on the ideal tensile strength of face-centered-cubic materials

2015 ◽  
Vol 111 (2) ◽  
pp. 26005 ◽  
Author(s):  
Duc Tam Ho ◽  
Soon-Dong Park ◽  
Soon-Yong Kwon ◽  
Tong-Seok Han ◽  
Sung Youb Kim
Keyword(s):  
Tensile Strength ◽  
Face Centered Cubic ◽  
Transverse Loading ◽  
Cubic Materials ◽  
Face Centered ◽  
The Ideal

Voids in Irradiated Tungsten and Molybdenum

1969 ◽  
Vol 27 ◽  
pp. 190-191
Author(s):  
Robert C. Rau ◽  
Robert L. Ladd
Keyword(s):  
Melting Point ◽  
Fast Neutron ◽  
Neutron Irradiation ◽  
Elevated Temperatures ◽  
Irradiation Temperature ◽  
The Body ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Cubic Metals ◽  
Face Centered

Recent studies have shown the presence of voids in several face-centered cubic metals after neutron irradiation at elevated temperatures. These voids were found when the irradiation temperature was above 0.3 Tm where Tm is the absolute melting point, and were ascribed to the agglomeration of lattice vacancies resulting from fast neutron generated displacement cascades. The present paper reports the existence of similar voids in the body-centered cubic metals tungsten and molybdenum.

A study of interface sliding at F.C.C.-B.C.C. boundaries in a Cu-Zn alloy

1978 ◽  
Vol 36 (1) ◽  
pp. 422-423
Author(s):  
F. Monchoux ◽  
A. Rocher ◽  
J.L. Martin
Keyword(s):  
Face Centered Cubic ◽  
Creep Tests ◽  
High Voltage Electron Microscopy ◽  
Diffusion Treatment ◽  
Voltage Electron ◽  
The Face ◽  
Face Centered ◽  
Interface Sliding ◽  
Zn Alloy ◽  
Made In

Interphase sliding is an important phenomenon of high temperature plasticity. In order to study the microstructural changes associated with it, as well as its influence on the strain rate dependence on stress and temperature, plane boundaries were obtained by welding together two polycrystals of Cu-Zn alloys having the face centered cubic and body centered cubic structures respectively following the procedure described in (1). These specimens were then deformed in shear along the interface on a creep machine (2) at the same temperature as that of the diffusion treatment so as to avoid any precipitation. The present paper reports observations by conventional and high voltage electron microscopy of the microstructure of both phases, in the vicinity of the phase boundary, after different creep tests corresponding to various deformation conditions.Foils were cut by spark machining out of the bulk samples, 0.2 mm thick. They were then electropolished down to 0.1 mm, after which a hole with thin edges was made in an area including the boundary

Microstructure of Electro-Eroded Cemented Carbide Surfaces

1968 ◽  
Vol 26 ◽  
pp. 284-285
Author(s):  
V. N. Filimonenko ◽  
M. H. Richman ◽  
J. Gurland
Keyword(s):  
Surface Layer ◽  
Cobalt Content ◽  
Cemented Carbides ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Metallographic Examination ◽  
Standard Procedures ◽  
Face Centered ◽  
Diamond Paste ◽  
Plastic Carbon

The high temperatures and pressures that are found in a spark gap during electrical discharging lead to a sharp phase transition and structural transformation in the surface layer of cemented carbides containing WC and cobalt. By means of X-ray diffraction both W2C and a high-temperature monocarbide of tungsten (face-centered cubic) were detected after electro-erosion. The W2C forms as a result of the peritectic reaction, WC → W2C+C. The existence and amount of the phases depend on both the energy of the electro-spark discharge and the cobalt content. In the case of a low-energy discharge (i.e. C=0.01μF, V = 300v), WC(f.c.c.) is generally formed in the surface layer. However, at high energies, (e.g. C=30μF, V = 300v), W2C is formed at the surface in preference to the monocarbide. The phase transformations in the surface layer are retarded by the presence of larger percentages of cobalt.Metallographic examination of the electro-eroded surfaces of cemented carbides was carried out on samples with 5-30% cobalt content. The specimens were first metallographically polished using diamond paste and standard procedures and then subjected to various electrical discharges on a Servomet spark machining device. The samples were then repolished and etched in a 3% NH4OH electrolyte at -0.5 amp/cm2. Two stage plastic-carbon replicas were then made and shadowed with chromium at 27°.

Faceted antiphase boundaries in GaAs grown on Ge

1987 ◽  
Vol 45 ◽  
pp. 314-315
Author(s):  
N.-H. Cho ◽  
S. McKernan ◽  
C.B. Carter ◽  
K. Wagner
Keyword(s):  
Cross Section ◽  
Atomic Resolution ◽  
Face Centered Cubic ◽  
Electrical Behavior ◽  
Sphalerite Structure ◽  
Antiphase Boundaries ◽  
Transmission Electron ◽  
Face Centered ◽  
Quality Material ◽  
Simulated Images

Interest has recently increased in the possibility of growing III-V compounds epitactically on non-polar substrates to produce device quality material. Antiphase boundaries (APBs) may then develop in the GaAs epilayer because it has sphalerite structure (face-centered cubic with a two-atom basis). This planar defect may then influence the electrical behavior of the GaAs epilayer. The orientation of APBs and their propagation into GaAs epilayers have been investigated experimentally using both flat-on and cross-section transmission electron microscope techniques. APBs parallel to (110) plane have been viewed at the atomic resolution and compared to simulated images.Antiphase boundaries were observed in GaAs epilayers grown on (001) Ge substrates. In the image shown in Fig.1, which was obtained from a flat-on sample, the (110) APB planes can be seen end-on; the faceted APB is visible because of the stacking fault-like fringes arising from a lattice translation at this interface.

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