Role of electron density of liquid metals and bandgap energy of solid ceramics on the work of adhesion and wettability of metal-ceramic systems

1992 ◽  
Vol 11 (13) ◽  
pp. 903-905 ◽  
Author(s):  
J. G. Li
Keyword(s):  
Electron Density ◽  
Liquid Metals ◽  
Work Of Adhesion ◽  
Bandgap Energy ◽  
Metal Ceramic

Unusually high electron density in an intermolecular non-bonding region: Role of metal substrate

2017 ◽  
Vol 28 (4) ◽  
pp. 759-764 ◽  
Author(s):  
Chen-Guang Wang ◽  
Zhi-Hai Cheng ◽  
Xiao-Hui Qiu ◽  
Wei Ji
Keyword(s):  
Electron Density ◽  
Metal Substrate ◽  
High Electron ◽  
High Electron Density

scholarly journals Examining the role of flare-driven D-region electron density enhancement on Doppler Flash

2020 ◽  
Author(s):  
Shibaji Chakraborty ◽  
Liying Qian ◽  
J. Michael Ruohoniemi ◽  
Joseph Baker ◽  
Joseph McInerney
Keyword(s):  
Electron Density ◽  
Density Enhancement ◽  
D Region

scholarly journals Comparison of Different Methods of Prosthetic Rehabilitation in Anterior Region

2015 ◽  
Vol 5 (4) ◽  
pp. 110-113
Author(s):  
Antonio crispino ◽  
Gaetano Pisano ◽  
Leonzio Fortunato
Keyword(s):  
Case Report ◽  
Clinical Case ◽  
Clinical Success ◽  
Individual Case ◽  
Anterior Region ◽  
Prosthetic Rehabilitation ◽  
All Ceramic ◽  
Metal Ceramic ◽  
Natural Teeth

ABSTRACT Scope of work The purpose of this work is the analysis and comparison of the various methods available for the realization of fixed restorations on natural teeth in the anterior sector with the presentation of some case report series. Materials and methods The methods used in relation to the clinical case, are the metal-ceramic, the galvan-ceramic, all- ceramic and porcelain veneers. Results It highlights indications and limitations of each of the methods proposed, emphasizing the prominent role of esthetics in the rehabilitation sector of the front. Conclusion The materials and techniques available, with proper clinical evaluation and to a timely therapeutic planning, are the basis of the rehabilitative ideal choice for each individual case, and they also depend on the achievement of clinical success. How to cite this article Crispino A, Pisano G, Fortunato L. Comparison of Different Methods of Prosthetic Rehabilitation in Anterior Region. Int J Prosthodont Restor Dent 2015;5(4):110-113.

scholarly journals Detachment of compliant films adhered to stiff substrates via van der Waals interactions: role of frictional sliding during peeling

2014 ◽  
Vol 11 (97) ◽  
pp. 20140453 ◽  
Author(s):  
Rachel R. Collino ◽  
Noah R. Philips ◽  
Michael N. Rossol ◽  
Robert M. McMeeking ◽  
Matthew R. Begley
Keyword(s):  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Work Of Adhesion ◽  
Interface Fracture ◽  
Strong Function ◽  
Frictional Sliding ◽  
Fracture Models ◽  
Synthetic Adhesives ◽  
Interface Sliding

The remarkable ability of some plants and animals to cling strongly to substrates despite relatively weak interfacial bonds has important implications for the development of synthetic adhesives. Here, we examine the origins of large detachment forces using a thin elastomer tape adhered to a glass slide via van der Waals interactions, which serves as a model system for geckos, mussels and ivy. The forces required for peeling of the tape are shown to be a strong function of the angle of peeling, which is a consequence of frictional sliding at the edge of attachment that serves to dissipate energy that would otherwise drive detachment. Experiments and theory demonstrate that proper accounting for frictional sliding leads to an inferred work of adhesion of only approximately 0.5 J m −2 (defined for purely normal separations) for all load orientations. This starkly contrasts with the interface energies inferred using conventional interface fracture models that assume pure sticking behaviour, which are considerably larger and shown to depend not only on the mode-mixity, but also on the magnitude of the mode-I stress intensity factor. The implications for developing frameworks to predict detachment forces in the presence of interface sliding are briefly discussed.

Interaction and Electron Density Properties of MKr42+ (M=Cu, Ag and Au): ab initio Calculation

2011 ◽  
Vol 64 (3) ◽  
pp. 339 ◽  
Author(s):  
Li Xinying ◽  
Cao Xue
Keyword(s):  
Electron Density ◽  
Quantum Chemical ◽  
Ab Initio Calculation ◽  
Gradient Analysis ◽  
Natural Bond Orbital ◽  
Theoretical Level ◽  
Covalent Contribution ◽  
Reduced Density Gradient ◽  
Reduced Density

Quantum chemical calculations of the structures and stabilities of the MKr42+ series at the CCSD(T) theoretical level have been performed. The role of the interaction was investigated using the natural bond orbital (NBO), Laplacian, electron density deformation, electron localization function and reduced density gradient analysis. The results show that a covalent contribution occurs in the Kr-M2+ bonding.

First Principles Calculations for Metal/Ceramic Interfaces

1994 ◽  
Vol 357 ◽  
Author(s):  
M. W. Finnis ◽  
C. Kruse ◽  
U. SchÖnberger
Keyword(s):  
Electronic Structure ◽  
High Resolution ◽  
Ab Initio ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Work Of Adhesion ◽  
First Principles Calculations ◽  
Resolution Electron ◽  
Metal Ceramic

AbstractWe discuss the recent first principles calculations of the properties of interfaces between metals and oxides. This type of calculation is parameter-free, and exploits the density functional theory in the local density approximation to obtain the electronic structure of the system. At the same time the equilibrium atomic structure is sought, which minimises the excess energy of the interface. Up to now calculations of this type have been made for a few model interfaces which are atomically coherent, that is with commensurate lattices. Examples are Ag/MgO and Nb/Al2O3. In these cases it has been possible to predict the structures observed by high resolution electron microscopy. The calculations are actually made in a supercell geometry, in which there are alternating nanolayers of metal and ceramic. Because of the effectiveness of metallic screening in particular, the interfaces between the nanolayers do not interfere much with each other.Besides the electronic structure of the interface, such calculations have provided values of the ideal work of adhesion. Electrostatic image forces in conjunction with the elementary ionic model provide a simple framework for understanding the results.An important role of such calculations is to develop intuition about the nature of the bonding, including the effects of charge transfer, which has formerly only been described in an empirical way. It may then be possible to build atomistic models of the metal/ceramic interaction which have a sound physical basis and can be calibrated against ab initio results. Simpler models are necessary if larger systems, including misfit dislocations and other defects, are to be simulated, with a view to understanding the atomic processes of growth and failure. Another area in which ab initio calculations can be expected to contribute is in the chemistry of impurity segregation and its effect at interfaces. Such theoretical tools are a natural partner to the experimental technique of high resolution electron energy loss spectroscopy for studying the local chemical environment at an interface.

Segregation of Silicon in Metal-Alumina Composites

1999 ◽  
Vol 5 (S2) ◽  
pp. 624-625
Author(s):  
R.Y. Hashimoto ◽  
E.S.K. Menon ◽  
A.G. Fox
Keyword(s):  
Boundary Segregation ◽  
Ceramic Composites ◽  
Pure Metal ◽  
Triple Junctions ◽  
Sintering Aid ◽  
Commercial Alumina ◽  
Metal Ceramic ◽  
Alumina Composites ◽  
Ceramic Interfaces

A common impurity in polycrystalline commercial alumina is Si since silica is often added as a sintering aid. There have been several studies on impurities in alumina, and substantial degree of grain boundary segregation has been found to occur. Alumina-metal composites have found several applications especially in the electronic industry and consequently systems such as alumina-copper have been studied exhaustively. However, the role of impurities in metal-alumina composites has not been fully explored. Studies of Pt-alumina composites has shown that silicon is present at the interface of vacuum, diffusion bonded samples. Our earlier studies have shown that Si indeed segregates to the triple junctions and grain boundaries in alumina and in alumina-copper composites, often Si segregates to the metal-ceramic interfaces as well. This investigation concentrates on the distribution of silicon in copper-alumina in comparison to aluminum-alumina composites.The metal-ceramic composites were prepared by diffusion bonding 99.99% pure metal foils sandwiched in between commercially available sintered alumina (∼99.5% pure) substrates for several hours in vacuum.

scholarly journals On the role of vertical electron density gradients in the generation of type II irregularities associated with blanketing ES(ESb) during counter equatorial electrojet events: A case study

Radio Science ◽  
2004 ◽  
Vol 39 (3) ◽  
pp. n/a-n/a ◽  
Author(s):  
C. V. Devasia ◽  
N. Jyoti ◽  
K. S. V. Subbarao ◽  
Diwakar Tiwari ◽  
C. Raghava Reddi ◽  
...  
Keyword(s):  
Electron Density ◽  
Equatorial Electrojet ◽  
Density Gradients ◽  
Type Ii
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