scholarly journals Theoretical Evaluation of Possibility to Control Nucleation and Growth of Heteroepitaxial Carbon Films by Applied Fields

2017 ◽  
Vol 3 (3) ◽  
pp. 211 ◽  
Author(s):  
B.Z. Mansurov ◽  
G.K. Kalykova ◽  
N.N. Myasnikova ◽  
L.V. Mikhailov
Keyword(s):  
Atomic Hydrogen ◽  
Diamond Films ◽  
Chemical Properties ◽  
Copper Surface ◽  
Carbon Films ◽  
Crystalline Lattice ◽  
Oriented Growth ◽  
Theoretical Evaluation ◽  
Cell Parameters ◽  
Applied Fields

On the basis of the literature review, comparison of physical and chemical properties of materials and calculations, it was showed that the copper, saturated with hydrogen, is an appropriate substrate material<br />for heteroepitaxial growth of diamond films. The atomic hydrogen in tetrapores of copper crystalline lattice will be the crystallisation centre of carbon. Herewith the difference in lattice cell parameters between<br />the substrate and the growing diamond film is considerably reduced, i.e. epitaxial growth of crystal is possible. Besides, the disposition of tetrapores on the copper surface (111) and, respectively, of atomic hydrogen located in them, creates conditions for preferential formation of tetragonal bonds of carbon. The estimations have shown that it is possible to create conditions for preferential oriented growth of diamond films through changing the magnitude and configuration of applied fields.

scholarly journals Structure Determination of C23H19N4OBr from Synchrotron Data

2014 ◽  
Vol 70 (a1) ◽  
pp. C141-C141
Author(s):  
Ozen Ozgen ◽  
Engin Kendi ◽  
Semra Koyunoglu ◽  
Akgul Yesilada ◽  
Hwo-Shuenn Sheu
Keyword(s):  
Powder Diffraction ◽  
Structural Information ◽  
Chemical Properties ◽  
Biological Properties ◽  
Cell Parameters ◽  
Fundamental Understanding ◽  
Physical And Chemical ◽  
Radiation Research ◽  
And Chemical Properties

A significant part of medicine is based on the discovery and development of drugs. It is very important to know the crystal structure of pharmaceutical compounds for fundamental understanding of structure, physical and chemical properties. Many of these materials are available only as powders. So any structural information must be obtained from powder diffraction. I am going to present following the stages while solving the structure of C23H19N4OBr, 2-[3-phenyl-4(m-bromophenyl)-2-pyrazolin-1-yl]-3-methyl-4(3H)-quinazolinone, from 2-pyrazolines derivatives. The compounds are known to display various biological properties such as fungicidal insecticidal, anti bacterial, anti viral activities, pharmacological properties such as antiinflammatory agents and have industral properties(1). The powder diffraction data was collected with Debye Scherrer camera at the BL01C2 beamline at room temperature in National Synchrotron Radiation Research Center(NSRRC), Taiwan. X-ray of wavelength was 1.0333Å. This compound crystallizes in orthorhombic system space group P bca, Z=8, unit cell parameters of a=25.83(1)Å, b=15.55(5)Å, c=10.63(3)Å, and V=4266.0(10)Å3. Reliability factors were reached Rwp=0.075, Rp=0.053, RB=0.086 ve S=1.31 after Rietveld refinement.

scholarly journals Corrosion prevention of commercial alloys by air-water interface grown, edge on oriented, ultrathin squaraine film

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Rajiv Kumar Pandey ◽  
Richa Mishra ◽  
Gopal Ji ◽  
Rajiv Prakash
Keyword(s):  
Corrosion Protection ◽  
Surface Characterization ◽  
Electrochemical Techniques ◽  
Copper Substrate ◽  
Chemical Properties ◽  
Copper Surface ◽  
Ultrathin Film ◽  
Water Interface ◽  
Acid Media ◽  
Air Water Interface

Abstract Copper is one of the most demanded commercial metal/alloys in world market. The demand for copper in industries such as electrical, electronics, automobile, telecommunications, defence, etc. as well as in daily life has escalated in the recent years due to its versatile physical and chemical properties. However destruction of copper surface by any means, preferably corrosion, can limit its vast application. For protection from corrosion, various techniques are used to coat metal substrates with passivating materials. These techniques are either complex as well as expensive, or provide incomplete protection in acid media. To address these issues, floating film transfer method (FFTM) is utilized in this work for obtaining ultrathin film of squaraine (passivating molecule) as well as their easy and fast transfer over copper substrate. The squaraine film is deposited on copper substrate in layers, viz., 1 to 4 layers. The corrosion behavior is examined in 0.1 M HCl using electrochemical techniques as well as surface characterization techniques, which portray that copper corrosion is hampered in harmony with the layers deposited. Nearly 40% corrosion protection is reached for copper coated with 1 layer of squaraine. However, the protection is amplified up to 98% with 4 layers of squaraine, which clearly substantiates the supremacy of this coating method over reported methods of protection. This technique and the material (squaraine) are both for the first time being used in the field of corrosion protection. The easy growth of ultrathin film at air-water interface as well as its rapid transfer over substrate promotes use of FFTM for efficient corrosion protection on industrial scale.

Role of microstructure on the oxidation behavior of microwave plasma synthesized diamond and diamond-like carbon films

1990 ◽  
Vol 5 (11) ◽  
pp. 2445-2450 ◽  
Author(s):  
Rao R. Nimmagadda ◽  
A. Joshi ◽  
W. L. Hsu
Keyword(s):  
Oxidation Behavior ◽  
Microwave Plasma ◽  
Natural Diamond ◽  
Diamond Films ◽  
Cvd Diamond ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Gravimetric Analysis ◽  
Oxidation Rates

Oxidation kinetics of microwave plasma assisted CVD diamond and diamond-like carbon (DLC) films in flowing oxygen were evaluated in the temperature range of 500 to 750 °C and were compared with those of graphite and natural diamond. The diamond and DLC films were prepared using CH4/H2 ratios of 0.1, 0.25, 0.5, 1.0, and 2.0%. The films deposited at 0.1% ratio had a faceted crystalline structure with high sp3 content and as the ratio increased toward 2%, the films contained more and more fine crystalline sp2 bonded carbon. The oxidation rates were determined by thermal gravimetric analysis (TGA), which shows that the films deposited at ratios of 2, 1, and 0.5% oxidized at high rates and lie between the rates of natural diamond and graphite. The oxidation rate decreased with lower CH4/H2 ratio and the films deposited at 0.25 and 0.1% exhibited the lowest oxidation rates associated with the highest activation energies in the range of 293–285 kJ/mol · K. The oxidation behavior of microwave plasma assisted diamond films was similar to that of DC plasma assisted CVD diamond films. The results suggest that the same mechanism of oxidation is operational in both DC and microwave plasma assisted diamond films and is probably related to the microstructure and preferred orientation of the crystallites.

Diamond nucleation on nickel substrates seeded with non-diamond carbon

1994 ◽  
Vol 9 (5) ◽  
pp. 1063-1066 ◽  
Author(s):  
P.C. Yang ◽  
W. Zhu ◽  
J.T. Glass
Keyword(s):  
Single Crystal ◽  
High Temperatures ◽  
Atomic Hydrogen ◽  
Diamond Films ◽  
Nucleation Mechanism ◽  
Diamond Nucleation ◽  
Carbon Species ◽  
Nickel Substrates

Oriented diamond films have been nucleated on single crystal nickel substrates seeded with non-diamond carbon and annealed at high temperatures in atomic hydrogen. The non-diamond carbon seeds included graphite powders, fullerene (60) powders, and gaseous carbon species. It was found that these different non-diamond carbon powders or species were effective in the enhancement of oriented nucleation of diamond. The morphologies of diamond films were similar regardless of the types of carbon used, suggesting a common nucleation mechanism involved. Based on the experimental observations, a revised model was developed for the oriented nucleation of diamond on Ni.

scholarly journals A Review Paper on Biomimetic Calcium Phosphate Coatings

2015 ◽  
Vol 9 (1) ◽  
pp. 56-64 ◽  
Author(s):  
X. Lin ◽  
K. de Groot ◽  
D. Wang ◽  
Q. Hu ◽  
D. Wismeijer ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Drug Carrier ◽  
Chemical Properties ◽  
Giant Cells ◽  
Clinical Applications ◽  
Bone Morphogenetic Protein 2 ◽  
Crystalline Lattice ◽  
Calcium Phosphate Coating ◽  
Phosphate Coatings ◽  
Calcium Phosphate Coatings

Biomimetic calcium phosphate coatings have been developed for bone regeneration and repair because of their biocompatibility, osteoconductivity, and easy preparation. They can be rendered osteoinductive by incorporating an osteogenic agent, such as bone morphogenetic protein 2 (BMP-2), into the crystalline lattice work in physiological situations. The biomimetic calcium phosphate coating enables a controlled, slow and local release of BMP-2 when it undergoes cell mediated coating degradation induced by multinuclear cells, such as osteoclasts and foreign body giant cells, which mimics a physiologically similar release mode, to achieve sustained ectopic or orthotopic bone formation. Therefore, biomimetic calcium phosphate coatings are considered to be a promising delivery vehicle for osteogenic agents. In this review, we present an overview of biomimetic calcium phosphate coatings including their preparation techniques, physico-chemical properties, potential as drug carrier, and their pre-clinical application both in ectopic and orthotopic animal models. We briefly review some features of hydroxyapatite coatings and their clinical applications to gain insight into the clinical applications of biomimetic calcium phosphate coatings in the near future.

Role of atomic hydrogen density and energy in low power chemical vapor deposition synthesis of diamond films

2005 ◽  
Vol 478 (1-2) ◽  
pp. 77-90 ◽  
Author(s):  
Randell Mills ◽  
Jayasree Sankar ◽  
Andreas Voigt ◽  
Jiliang He ◽  
Paresh Ray ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Low Power ◽  
Vapor Deposition ◽  
Atomic Hydrogen ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Hydrogen Density

scholarly journals A Review on the Low-Dimensional and Hybridized Nanostructured Diamond Films

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Hongdong Li ◽  
Shaoheng Cheng ◽  
Jia Li ◽  
Jie Song
Keyword(s):  
High Performance ◽  
Diamond Films ◽  
Chemical Properties ◽  
Chemical Vapor ◽  
Industrial Applications ◽  
Research Field ◽  
Hybrid Nanostructures ◽  
High Rate ◽  
Low Dimensional ◽  
P Type

In the last decade, besides the breakthrough of high-rate growth of chemical vapor deposited single-crystal diamonds, numerous nanostructured diamond films have been rapidly developed in the research fields of the diamond-based sciences and industrial applications. The low-dimensional diamonds of two-dimensional atomic-thick nanofilms and nanostructural diamond on the surface of bulk diamond films have been theoretically and experimentally investigated. In addition, the diamond-related hybrid nanostructures of n-type oxide/p-type diamond and n-type nitride/p-type diamond, having high performance physical and chemical properties, are proposed for further applications. In this review, we first briefly introduce the three categories of diamond nanostructures and then outline the current advances in these topics, including their design, fabrication, characterization, and properties. Finally, we address the remaining challenges in the research field and the future activities.

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