Nano-sized fluorapatite particles by controlled precipitation from heterogeneous systems

2004 ◽  
pp. 110-118
Author(s):  
R. Zimehl ◽  
S. F. Willigeroth ◽  
M. Hannig ◽  
H. Frahm
Keyword(s):  
Heterogeneous Systems ◽  
Controlled Precipitation

A TEM investigation of a hyper-eutectic lead-tin alloy

1988 ◽  
Vol 46 ◽  
pp. 562-563
Author(s):  
John A. Sutliff
Keyword(s):  
Volume Diffusion ◽  
Eutectic Mixture ◽  
Precipitation Reaction ◽  
Directionally Solidified ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Diffusion Controlled ◽  
Discontinuous Precipitation Reaction ◽  
Controlled Precipitation

Near-eutectic Pb-Sn alloys are important solders used by the electronics industry. In these solders, the eutectic mixture, which solidifies last, is the important microstructural consituent. The orientation relation (OR) between the eutectic phases has previously been determined for directionally solidified (DS) eutectic alloys using x-ray diffraction or electron chanelling techniques. In the present investigation the microstructure of a conventionally cast, hyper-eutectic Pb-Sn alloy was examined by transmission electron microscopy (TEM) and the OR between the eutectic phases was determined by electron diffraction. Precipitates of Sn in Pb were also observed and the OR determined. The same OR was found in both the eutectic and precipitation reacted materials. While the precipitation of Sn in Pb was previously shown to occur by a discontinuous precipitation reaction,3 the present work confirms a recent finding that volume diffusion controlled precipitation can also occur.Samples that are representative of the solder's cast microstructure are difficult to prepare for TEM because the alloy is multiphase and the phases are soft.

Rationale and Design Considerations for a Semantic Mediator in Health Information Systems

1998 ◽  
Vol 37 (04/05) ◽  
pp. 518-526 ◽  
Author(s):  
D. Sauquet ◽  
M.-C. Jaulent ◽  
E. Zapletal ◽  
M. Lavril ◽  
P. Degoulet
Keyword(s):  
Information Systems ◽  
Software Engineering ◽  
Health Information ◽  
Rapid Development ◽  
Heterogeneous Systems ◽  
Health Information Systems ◽  
Semantic Interoperability ◽  
Point Of View ◽  
Current State ◽  
Engineering Environment

AbstractRapid development of community health information networks raises the issue of semantic interoperability between distributed and heterogeneous systems. Indeed, operational health information systems originate from heterogeneous teams of independent developers and have to cooperate in order to exchange data and services. A good cooperation is based on a good understanding of the messages exchanged between the systems. The main issue of semantic interoperability is to ensure that the exchange is not only possible but also meaningful. The main objective of this paper is to analyze semantic interoperability from a software engineering point of view. It describes the principles for the design of a semantic mediator (SM) in the framework of a distributed object manager (DOM). The mediator is itself a component that should allow the exchange of messages independently of languages and platforms. The functional architecture of such a SM is detailed. These principles have been partly applied in the context of the HEllOS object-oriented software engineering environment. The resulting service components are presented with their current state of achievement.

HEAT TRANSFER PECULIARITIES IN HETEROGENEOUS SYSTEMS WITH HIGH UNSTEADY-STATE HEAT TRANSFER RATES

1970 ◽  
Author(s):  
N.V. Antonishin ◽  
S. S. Zabrodsky ◽  
L.E. Simchenko ◽  
V.V. Lushchikov
Keyword(s):  
Heat Transfer ◽  
Heterogeneous Systems ◽  
Unsteady State ◽  
Transfer Rates ◽  
State Heat

Host-Guest Interactions on Electrode Surfaces for Immobilization of Molecular Catalysts

2020 ◽  
Author(s):  
Laurent Sévery ◽  
Jacek Szczerbiński ◽  
Mert Taskin ◽  
Isik Tuncay ◽  
Fernanda Brandalise Nunes ◽  
...  
Keyword(s):  
Aqueous Media ◽  
Heterogeneous Systems ◽  
Catalytic Systems ◽  
New Approach ◽  
Molecular Systems ◽  
Electrode Surfaces ◽  
Catalytic Surfaces ◽  
Oxide Electrodes ◽  
The Stability ◽  
Molecular Catalysts

The strategy of anchoring molecular catalysts on electrode surfaces combines the high selectivity and activity of molecular systems with the practicality of heterogeneous systems. The stability of molecular catalysts is, however, far less than that of traditional heterogeneous electrocatalysts, and therefore a method to easily replace anchored molecular catalysts that have degraded could make such electrosynthetic systems more attractive. Here, we apply a non-covalent “click” chemistry approach to reversibly bind molecular electrocatalysts to electrode surfaces via host-guest complexation with surface-anchored cyclodextrins. The host-guest interaction is remarkably strong and allows the flow of electrons between the electrode and the guest catalyst. Electrosynthesis in both organic and aqueous media was demonstrated on metal oxide electrodes, with stability on the order of hours. The catalytic surfaces can be recycled by controlled release of the guest from the host cavities and readsorption of fresh guest. This strategy represents a new approach to practical molecular-based catalytic systems.

Reaction Mechanisms of Inorganic and Organometallic Systems

2007 ◽  
Author(s):  
Robert B. Jordan
Keyword(s):  
Electron Transfer ◽  
Heterogeneous Systems ◽  
Asymmetric Hydrogenation ◽  
Pressure Effects ◽  
General Level ◽  
Hydrogenation Catalysts ◽  
Methyl Transferase ◽  
Transfer Region ◽  
Previous Edition ◽  
Oxide Synthase

This third edition retains the general level and scope of earlier editions, but has been substantially updated with over 900 new references covering the literature through 2005, and 140 more pages of text than the previous edition. In addition to the general updating of materials, there is new or greatly expanded coverage of topics such as Curtin-Hammett conditions, pressure effects, metal hydrides and asymmetric hydrogenation catalysts, the inverted electron-transfer region, intervalence electron transfer, photochemistry of metal carbonyls, methyl transferase and nitric oxide synthase. The new chapter on heterogeneous systems introduces the basic background to this industrially important area. The emphasis is on inorganic examples of gas/liquid and gas/liquid/solid systems and methods of determining heterogeneity.

scholarly journals Emergence of disconnected clusters in heterogeneous complex systems

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
István A. Kovács ◽  
Róbert Juhász
Keyword(s):  
Complex Systems ◽  
Percolation Theory ◽  
Contact Process ◽  
Heterogeneous Systems ◽  
Critical Dynamics ◽  
Magnetic Domains ◽  
3 Dimensional ◽  
Quantum Ising Model ◽  
Highly Correlated ◽  
Exact Renormalization Group

AbstractPercolation theory dictates an intuitive picture depicting correlated regions in complex systems as densely connected clusters. While this picture might be adequate at small scales and apart from criticality, we show that highly correlated sites in complex systems can be inherently disconnected. This finding indicates a counter-intuitive organization of dynamical correlations, where functional similarity decouples from physical connectivity. We illustrate the phenomenon on the example of the disordered contact process (DCP) of infection spreading in heterogeneous systems. We apply numerical simulations and an asymptotically exact renormalization group technique (SDRG) in 1, 2 and 3 dimensional systems as well as in two-dimensional lattices with long-ranged interactions. We conclude that the critical dynamics is well captured by mostly one, highly correlated, but spatially disconnected cluster. Our findings indicate that at criticality the relevant, simultaneously infected sites typically do not directly interact with each other. Due to the similarity of the SDRG equations, our results hold also for the critical behavior of the disordered quantum Ising model, leading to quantum correlated, yet spatially disconnected, magnetic domains.

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