Theoretical approach to reconstructive and morphotropic phase transitions

2005 ◽  
Vol 220 (8) ◽  
Author(s):  
Pierre Tolédano
Keyword(s):  
Phase Transitions ◽  
Vanadium Oxide ◽  
Theoretical Approach ◽  
Phenomenological Approach ◽  
Oxide System ◽  
Basic Concepts

AbstractThe basic concepts of the phenomenological approach to reconstructive transitions are illustrated by a working example, and their specific properties are outlined. A theoretical approach to morphotropic transformations, which are transitions between phases with different stoichiometries, is introduced through the description of the vanadium-oxide system.

AMPLIFICATION AND PHASE CONJUGATION OF WEAK SIGNALS

1993 ◽  
Vol 02 (01) ◽  
pp. 85-115 ◽  
Author(s):  
O.V. KULAGIN ◽  
G.A. PASMANIK ◽  
A.A. SHILOV
Keyword(s):  
Theoretical Approach ◽  
Phase Conjugation ◽  
High Sensitivity ◽  
Optical Systems ◽  
Experimental Investigations ◽  
Weak Signals ◽  
Optical Signals ◽  
Basic Concepts

The results of the study on phase conjugation of weak optical signals with the energy of units of photons are considered. Basic concepts of a semi-classical theoretical approach to describe amplification and phase conjugation (PC) of such signals are presented. A review is given on the experimental investigations that allowed for reaching a limit (about 1 photon for a mode) sensitivity of optical systems with PC-mirrors for a large (~ 105) number of resolution elements. High-sensitivity PC-mirror optical systems are demonstrated for a variety of applications.

Tuning the light absorption of a molecular vanadium oxide system for enhanced photooxidation performance

2011 ◽  
Vol 47 (11) ◽  
pp. 3114 ◽  
Author(s):  
Johannes Forster ◽  
Benedikt Rösner ◽  
Marat M. Khusniyarov ◽  
Carsten Streb
Keyword(s):  
Vanadium Oxide ◽  
Light Absorption ◽  
Oxide System

scholarly journals Combinatorial Synthesis and Evaluation of Vanadium Oxide Films

2011 ◽  
Vol 2-3 ◽  
pp. 1071-1076
Author(s):  
Qun Jiao Wang
Keyword(s):  
Vanadium Oxide ◽  
Composition Range ◽  
Growth Conditions ◽  
Oxide System ◽  
Combinatorial Synthesis ◽  
X Ray ◽  
Lattice Constants ◽  
Good Crystallinity ◽  
New Material ◽  
Vanadium Ion

Combinatorial technology is a powerful tool for new material exploration. La1-xCaxVO3composition-spread films were fabricated by combinatorial pulsed laser deposition and their thermoelectric properties were evaluated paralelly by the multi-channel thermoelectric measurement system. Concurrent X-ray analysis verified the formation of solid soluted films in the full composition range (0≤x≤1) as judged from the linear variation of the lattice constants. Growth conditions of LaVO3films were optimized. Good crystallinity of LaVO3film was obtained at 800°C, and the power factor of 0.6 µW/cm K2was achieved. The effects of oxygen content and the substitutions of Ca and Ce ions on TE properties of were also analysed respectively. Large TE properties in vanadium oxide system can be expected with the change of vanadium ion valence from 3+ to 2+. In La1-xCexVO3(0≤x≤1) system, Ce ion takes 3+ although Ce4+is stable in theory.

Measurement of solid state diffusion coefficients by a temperature-programmed method

1997 ◽  
Vol 12 (2) ◽  
pp. 467-473 ◽  
Author(s):  
Rajat Kapoor ◽  
S. T. Oyama
Keyword(s):  
Vanadium Oxide ◽  
Spherical Geometry ◽  
Oxide System ◽  
Solid Particles ◽  
Fickian Diffusion ◽  
Diffusive Transport ◽  
Diffusion Parameters ◽  
State Diffusion ◽  
Temperature Programmed ◽  
Oxide Sample

This paper presents a method for determining diffusivities in solids where the diffusing species desorbs or reacts at the external surfaces, and where the diffusivity does not vary appreciably with concentration. The method involves measuring the flux of the diffusive species out of the solid under the influence of a temperature program. A general model is developed, based on nonisothermal Fickian diffusion, which is applicable to solid particles with slab or spherical geometry. The solution is presented both as an analytical expression and as correlation charts of experimentally observable quantities. These charts are contour diagrams of the temperatures of peak diffusion rate with ln(E/R) and ln(D0/h2) as the axes, where E and D0 are the activation energy and pre-exponential terms of the diffusivity expression D = D0 exp(−E/RT), where R is the gas constant, and h the size of the particles. This paper deals exclusively with the case of oxygen diffusion in the vanadium oxide system. In this case, vanadium oxide was reduced in a reactive ammonia stream at conditions in which the surface reaction was fast compared to the diffusive transport process. Using this method the diffusion parameters were found to be D0 = 1.9 × 10−5 cm2 s−1 and E = 101 kJ/mol. The method was checked by varying the crystallite size of the vanadium oxide sample in the range 2h = 0.14−0.29 μm.

Evolutionary and Ideation Concepts for Cybersecurity Education

2022 ◽  
pp. 535-546
Author(s):  
David A Gould ◽  
Gregory Block ◽  
Simon Cleveland
Keyword(s):  
Knowledge Sharing ◽  
Evolutionary Algorithm ◽  
Theoretical Approach ◽  
Cyber Security ◽  
Biological Theory ◽  
Evolutionary Processes ◽  
Security Education ◽  
Basic Concepts

Evolution is a well-established biological theory, but some basic concepts can be abstracted and applied to non-biological domains such as the education domain for the purposes of knowledge sharing. There is a gap in the literature regarding how evolutionary processes can be applied to cyber security education. This article presents the general evolutionary algorithm and pairs it with an ideation technique (SCAMPER) to illustrate how certain evolutionary processes can be applied to cyber security education and learning. This paper does not attempt to close the gap, but rather offer a theoretical approach to address the gap.

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