Processing and Crystal Microstructure of Porous High Pressure Crystallized Nanodiamond/UHMWPE Biomedical Nanocomposite

2011 ◽  
Vol 328-330 ◽  
pp. 857-860 ◽  
Author(s):  
Chau Chang Chou ◽  
Jyun Hao You ◽  
Cheng Lun Wu
Keyword(s):  
High Pressure ◽  
Porous Structure ◽  
Biomedical Application ◽  
Processing Technique ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Bulk Hardness ◽  
Novel Processing ◽  
Pressure Crystallization ◽  
Ultra High Molecular Weight

A novel processing technique using a series of mixing/refluxing procedures and high-pressure crystallization (HPC) to fabricate nanodiamond/ultra high molecular weight polyethylene (ND/UHMWPE) nanocomposites for biomedical application was examined. For better mimetic lubrication, a porous structure was implemented in this study. Vitamin E as an anti-oxidation additive was also incorporated in selected porous specimens. The morphology of the specimens was investigated by transmission electron microscopy. The phase and crystal characteristics were revealed by Raman spectroscopy and X-ray diffraction. Shore D hardness was used to study the effect of the material’s porous structure and particle-induced crystallization on the bulk mechanical property. The dispersion of NDs in the UHMWPE matrix can significantly promote the crystallinity of the HPC specimens, even with a porous structure. However, the bulk hardness does not reveal this improvement in crystal microstructure.

High-pressure synthesis and crystal structure of the strontium tungstate Sr3W2O9

2018 ◽  
Vol 74 (2) ◽  
pp. 120-124 ◽  
Author(s):  
Daisuke Urushihara ◽  
Toru Asaka ◽  
Koichiro Fukuda ◽  
Hiroya Sakurai
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Pressure Phase ◽  
X Ray Diffraction ◽  
Rotation Symmetry ◽  
Synthesis And Crystal Structure ◽  
High Pressure Synthesis ◽  
Transmission Electron ◽  
Pressure Synthesis ◽  
Pressure Phase

The strontium tungstate compound Sr3W2O9 was prepared by a high-pressure synthesis technique. The crystal structure was determined by single-crystal X-ray diffraction and transmission electron microscopy. The structure was found to be a hettotype structure of the high-pressure phase of Ba3W2O9, which has corner-sharing octahedra with a trigonal symmetry. Sr3W2O9 has a monoclinic unit cell of C2/c symmetry. One characteristic of the structure is the breaking of the threefold rotation symmetry existing in the high-pressure phase of Ba3W2O9. The substitution of Sr at the Ba site results in a significant shortening of the interlayer distances of the [AO3] layers (A = Ba, Sr) and causes a distortion in the crystal structure. In Sr3W2O9, there is an off-centre displacement of W6+ ions in the WO6 octahedra. Such a displacement is also observed in the high-pressure phase of Ba3W2O9.

Electrochemical Testing and Structural Characterisation of Nickel Based Catalytic Coatings Produced by Direct Spraying

1998 ◽  
Vol 549 ◽  
Author(s):  
S.M.A. Sillitto ◽  
N.J.E. Adkins ◽  
D.R. Hodgson ◽  
E. Paul ◽  
R.M. Ormerod
Keyword(s):  
Raney Nickel ◽  
Phase Distribution ◽  
Pilot Scale ◽  
Processing Technique ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
Structural Characterisation ◽  
Beneficial Effects ◽  
Electrochemical Testing ◽  
Novel Processing

AbstractIn this paper a novel processing technique has been used to produce a range of low overpotential nickel based electrocatalytic coatings for use in the Chlor-alkali industry. These coatings include pure nickel as well as Raney nickel alloys, with particular focus upon the beneficial effects of molybdenum additions to Raney nickel.Structural characterisation of all coatings has been carried out using X-ray diffraction for quantitative phase identification, backed up by optical and electron microscopy for analysis of phase distribution. Measurement of the coatings' electrochemical properties has been performed in fully functioning micro-pilot scale electrolysis cells.

scholarly journals Toward Understanding of the Effect of Nucleation Temperature on Porous Structure of Micro-Mesoporous Composite Molecular Sieves and Related Crystallization Mechanism

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 777 ◽  
Author(s):  
Chunwei Shi ◽  
Jingjing Liu ◽  
Wenyuan Wu ◽  
Xue Bian ◽  
Ping Chen ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Porous Structure ◽  
Molecular Sieves ◽  
Crystallization Mechanism ◽  
Nucleation Temperature ◽  
X Ray Diffraction ◽  
Mesoporous Composite ◽  
Transmission Electron ◽  
Isomerization Selectivity ◽  
Crystal Particle

Although micro-mesoporous composite molecular sieves have received significant attention due to their desirable properties, they still lack systematic studies on their crystallization process to achieve controllable synthesis of composite molecular sieves. In this study, a series of Y/SBA-15 micro-mesoporous composite molecular sieves with different porous structures were synthesized by tuning nucleation temperature, based on epitaxial growth on the outer surface of the Y-type crystal particle. All composite molecular sieves were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM). Moreover, the effect of nucleation temperature on the structure of composite molecular sieves was investigated, while the crystallization mechanism was also explored. Furthermore, the performance of the molecular sieves on isomerization of n-pentane was investigated, the results suggested that the isomerization selectivity was positively correlated with regularity degree of the mesoporous porous structure, where the highest isomerization reached 95.81%. This work suggests that nucleation temperature plays a key role in structures of micro-mesoporous composite molecular sieves, providing a solid basis for the further development of functional composite molecular sieves.

Microstructural analysis of high-pressure compressed C60

2001 ◽  
Vol 16 (7) ◽  
pp. 1960-1966 ◽  
Author(s):  
K. Miyazawa ◽  
H. Satsuki ◽  
M. Kuwabara ◽  
M. Akaishi
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Pressure ◽  
High Resolution ◽  
Microstructural Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Hardness Tests ◽  
Lattice Planes

The structure and hardness of C60 bulk specimens compressed under 5.5 GPa at room temperature to 600 °C are investigated by high-resolution transmission electron microscopy, x-ray diffraction, and micro-Vickers hardness tests. A strong accumulation of the [1 1 0]tr orientation of high-pressure-treated C60 specimens was developed along the compression axis, and stacking faults and nano-sized deformation twins were introduced into the C60 specimens compressed at 450–600 °C. Curved lattice planes indicating a polymerization of C60 were observed by high resolution transmission electron microscopy (HRTEM). The polymerization of the high-pressure-compressed C60 is also supported by the computer simulation of HRTEM images.

Structural Instability of the Ceramic Coating in a Metal-Ceramic Composite Induced Through Control of Chemistry of the Bonding Atmosphere

1992 ◽  
Vol 280 ◽  
Author(s):  
Abhijit Ray
Keyword(s):  
Amorphous Phase ◽  
Bonding Temperature ◽  
Structural Instability ◽  
Processing Technique ◽  
High Concentration ◽  
Ceramic Phase ◽  
Enhanced Diffusion ◽  
Transmission Electron ◽  
Metal Ceramic ◽  
Novel Processing

ABSTRACTA novel processing technique has been developed to coat Al2O3 on Nb in an argon atmosphere with very low O2 content. It has been proposed1 that the low O2 content helped to increase the defect concentration in the ceramic phase resulting in an enhanced diffusion of Nb into Al2O3 at the metal-ceramic interface at a relatively low bonding temperature. A mathematical model has been developed1 to understand the effect of purified bonding atmosphere on interfacial diffusion. While diffraction studies in the transmission electron microscope revealed1 extensive amorphization at the metal-ceramic interface, EDX analysis showed1 that the interfacial amorphous phase has a very high concentration of O. Additionally, this phase is found to contain Al and Nb. The interfacial phase is formed due to the diffusion of Nb into the ceramic phase. The paradoxical phenomenon of O enrichment of the interfacial amorphous phase in a low O2 containing bonding atmosphere is due to the loss of gaseous oxides of Al from this phase. These oxides have relatively less proportion of O compared to Al2O3. Continuous loss of such oxides from the amorphous phase to the gaseous phase will, therefore, result in an O to Al ratio (in the amorphous phase) far exceeding that in Al2O3 (3:2).

Synthesis and Characterization Silver, Zinc Oxide and Hybrid Silver/Zinc Oxide Nanoparticles for Antimicrobial Applications

Nano LIFE ◽  
2014 ◽  
Vol 04 (01) ◽  
pp. 1440003 ◽  
Author(s):  
Myisha Roberson ◽  
Vijaya Rangari ◽  
Shaik Jeelani ◽  
Temesgen Samuel ◽  
Clayton Yates
Keyword(s):  
Zinc Oxide ◽  
Zno Nanoparticles ◽  
Biomedical Application ◽  
Fungal Growth ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Zno Nps ◽  
E Coli ◽  
Transmission Electron ◽  
20 Nm

Silver ( Ag ) and zinc oxide ( ZnO ) are well known for both antimicrobial and pro-healing properties. Here, we present a novel method to synthesize Ag and ZnO nanoparticles (NPs), as well as hybrid Ag / ZnO NPs using a custom, temperature controlled microwave assisted technique. Microwave synthesis has been shown not only to enhance the rate of chemical reactions, but also in some cases to give higher product yields over thermal heating. The as-synthesized NPs were characterized by X-ray diffraction (XRD) to study the crystalline structure, composition and purity. Transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) was used to study particle size, shape, composition and morphology. These results indicated that the as-prepared Ag NPs are spherical in shape and ~ 20 nm in sizes. The ZnO NPs are typically rod shaped and the particle sizes are ~ 20 nm in width and 100 nm in length. These NPs were tested for antibacterial and/or antifungal properties using disc diffusion assays. Results show microwave synthesized NPs inhibit growth of S. aureus, E. coli and C. albicans at 50 μ g/mL treatment concentration. Ag NPs were most effective in inhibiting bacterial and fungal growth at the concentrations tested followed by hybrid Ag / ZnO and ZnO nanoparticles. These results also suggest that the hybridization of ZnO to Ag NPs may reduce the toxicity of Ag NPs. Further studies are needed to understand the functional interaction between the two types of NPs and to improve their ability for biological or biomedical application.

Structures and phase transitions of B-Ta2O5 and Z-Ta2O5: two high-pressure forms of Ta2O5

2000 ◽  
Vol 56 (4) ◽  
pp. 659-665 ◽  
Author(s):  
I. P. Zibrov ◽  
V. P. Filonenko ◽  
M. Sundberg ◽  
P.-E. Werner
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Pressure ◽  
Rietveld Method ◽  
High Pressure Chamber ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated

A sample of Ta2O5, ditantalum pentaoxide, heat-treated in a `toroid'-type high-pressure chamber at P = 8 GPa and T = 1470 K, was studied by X-ray powder diffraction and high-resolution transmission electron microscopy (HRTEM). Two high-pressure modifications of Ta2O5, isostructural with B-Nb2O5 and Z-Nb2O5, were identified from the X-ray powder pattern. Both structures were refined by the Rietveld method from the X-ray diffraction data: B-Ta2O5, a = 12.7853 (4), b = 4.8537 (1), c = 5.5276 (2) Å, β = 104.264 (2)°, V = 332.45 Å3, Z = 4, space group C2/c; Z-Ta2O5, a = 5.2252 (1), b = 4.6991 (1), c = 5.8534 (1) Å, β = 108.200 (2)°, V = 136.53 Å3, Z = 2, space group C2. The Z-Ta2O5 modification is new. The Ta atoms are six-coordinated in B-Ta2O5 and seven-coordinated in Z-Ta2O5. The two structures are closely related, which makes an intergrowth and a transformation between them possible. An idealized model of the intergrowth structure has been given. The HRTEM study showed defect-rich B-Ta2O5 crystals, which could be interpreted as an intergrowth between the B-Ta2O5 and Z-Ta2O5 phases.

scholarly journals Morphology and adsorption of chromium ion on uranium 1,2,4,5-benzenetetracarboxylic acid metal organic framework (MOF)

2016 ◽  
Vol 70 (5) ◽  
pp. 565-572 ◽  
Author(s):  
Remy Vala ◽  
Donbebe Wankasi ◽  
Ezekiel Dikio
Keyword(s):  
Electron Microscopy ◽  
Porous Structure ◽  
Metal Organic Framework ◽  
Tetracarboxylic Acid ◽  
X Ray Diffraction ◽  
Kinetic Determination ◽  
Transmission Electron ◽  
Metal Organic ◽  
Organic Framework

In this paper, we report the synthesis of metal organic framework of uranium 1,2,4,5-benzene tetracarboxylic acid (U-H4btec MOF) by solvothermal method. The obtained MOF was characterized by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD), Energy dispersive spectroscopy (EDS), thermogravimetric and differential thermogravimetric analysis (TGA/DTA). The morphology of the uranium 1,2,4,5-benzene tetracarboxylic acid MOF observed by SEM, revealed the presence of flaky porous structure. Adsorption of Cr3+ from aqueous solution onto the uranium 1,2,4,5-benzene tetracarboxylic acid MOF was systematically studied. Langmuir and Freundlich adsorption isotherms were applied to determine the adsorption capacity of the MOF to form a monolayer. Kinetic determination of the adsorption of Cr3+ suggested both chemisorption and physisorption probably due to the presence of carbonyl groups within the MOF and its porous structure.

scholarly journals Optimized Tin Bismuth Alloy Modified with Silver Vanadate Nanorods Prepared via Powder Metallurgy: Search for Biomedical Application

2020 ◽  
Vol 9 (4) ◽  
pp. 1615-1626
Keyword(s):  
Electron Microscopy ◽  
Powder Metallurgy ◽  
Biomedical Application ◽  
Mechanical Tests ◽  
Bacterial Strains ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silver Vanadate ◽  
Transmission Electron ◽  
Bismuth Alloy

In this study, a new bismuth tin eutectic alloy and other samples of the same composition doped with variable concentration of silver vanadate nanorods were prepared using new route powder metallurgy. X-ray diffraction of prepared silver vanadate approves the formation of  phase silver vanadate (-AgVO3). Transmission electron microscopy shows the formation of AgVO3 nanorods of radius ranging (20-40 nm). X-ray diffraction of alloys doped with silver vanadate and mechanical tests show that hardness and creep behavior data are composition-dependent parameters with silver vanadate content. Antimicrobial tests against pathogenic grams, fungi, and yeast showed that the addition of silver vanadate nanorods stimulates the action of hydride alloy and increases their activity against bacterial strains. In hospitals, biomedical devices may contaminate infection; doping devices with nanoparticles may make it auto clean besides conserving its mechanical properties.

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