Optical properties of a thin layer of the Vanadium dioxide at the metal state

2015 ◽  
Vol 9 (1) ◽  
pp. 2303-2310
Author(s):  
Abderrahim Benchaib ◽  
Abdesselam Mdaa ◽  
Izeddine Zorkani ◽  
Anouar Jorio
Keyword(s):  
Optical Properties ◽  
Thin Layer ◽  
Vanadium Dioxide ◽  
Ultra Violet ◽  
Index Of Refraction ◽  
Cost Of Energy ◽  
Infra Red ◽  
Metal State ◽  
The Cost ◽  
Reversible Phase

The vanadium dioxide VO₂ currently became very motivating for the nanotechnologies’ researchers. It makes party of the intelligent materials because these optical properties abruptly change semiconductor state with metal at a critical  temperature θ = 68°C. This transition from reversible phase is carried out from a monoclinical structure characterizing its semiconductor state at low temperature towards the metal state of this material which becomes tétragonal rutile for  θ ˃ 68°C ; it is done during a few nanoseconds. Several studies were made on this material in a massive state and a thin layer. We will simulate by Maple the constant optics of a thin layer of VO₂ thickness z = 82 nm for the metal state according to the energy ω of the incidental photons in the energy interval: 0.001242 ≤ ω(ev) ≤ 6, from the infra-red (I.R) to the ultra-violet (U.V) so as to be able to control the various technological nano applications, like the detectors I.R or the U.V,  the intelligent windows to  increase  the energy efficiency in the buildings in order to save the cost of energy consumption by electric air-conditioning and the paintings containing nano crystals of this material. The constant optics, which we will simulate, is: the index of refraction, the reflectivity, the transmittivity, the coefficient of extinction, the dielectric functions ԑ₁ real part and  ԑ₂  imaginary part of the permittivity complexes ԑ of this material and the coefficient absorption. 

Optical properties of the Vanadium dioxide

2015 ◽  
Vol 8 (2) ◽  
pp. 2148-2155 ◽  
Author(s):  
Abderrahim Benchaib ◽  
Abdesselam Mdaa ◽  
Izeddine Zorkani ◽  
Anouar Jorio
Keyword(s):  
Energy Efficiency ◽  
Optical Properties ◽  
Critical Temperature ◽  
Thin Layer ◽  
Dielectric Function ◽  
Vanadium Dioxide ◽  
Ultra Violet ◽  
Index Of Refraction ◽  
Practical Utility ◽  
Infra Red

The vanadium dioxide is a material thermo chromium which sees its optical properties changing at the time of the transition from the phase of semiconductor state ↔ metal, at a critical temperature of 68°C. The study of the optical properties of a thin layer of VO₂ thickness 82 nm, such as the dielectric function, the index of refraction, the coefficient ofextinction, the absorption’s coefficient, the reflectivity, the transmittivity, in the photonic spectrum of energy ω located inthe interval: 0.001242 ≤ ω (ev) ≤ 6, enables us to control well its practical utility in various applications, like the intelligentpanes, the photovoltaic, paintings for increasing energy efficiency in buildings, detectors of infra-red (I.R) or ultra-violet(U.V). We will make simulations with Maple and compare our results with those of the literature

Optical properties of the massive Vanadium dioxide

2015 ◽  
Vol 8 (3) ◽  
pp. 2222-2230
Author(s):  
Abderrahim Benchaib ◽  
Abdesselam Mdaa ◽  
Izeddine Zorkani ◽  
Anouar Jorio
Keyword(s):  
Optical Properties ◽  
Variational Method ◽  
Band Gap ◽  
Effective Mass ◽  
Dielectric Function ◽  
Vanadium Dioxide ◽  
Normal Incidence ◽  
Index Of Refraction ◽  
The Real

 We can easily extract the optical properties from a material starting from its permittivity complexes ԑ; . The real part of this dielectric function clearly takes its place in the Colombian interaction of an exciton. We are interested in exciton 1S in the case of the massive vanadium dioxide. We will solve Schrödinger’s equation for this exciton by variational method and we obtain  according to energy E of the same exciton. We make a simulation by means of the Maple software of   and of the index of refraction n according to energy E of the exciton 1S, around and far from the band gap of this material while being based on the approximation of the effective mass. We will extract the reflectivity R and transmittivity T of the massive vanadium dioxide for the normal incidence of the incidental photons by considering a slightly absorbent semiconductor state. 

scholarly journals Two types of diamond

1933 ◽  
Vol 232 (707-720) ◽  
pp. 463-535 ◽  
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Polarized Light ◽  
Ultra Violet ◽  
The Other ◽  
X Ray ◽  
King's College ◽  
Infra Red ◽  
Ray Patterns

Among a number of diamonds supplied to us by Professor W. T. Gordon, of King’s College, London, one, by a fortunate chance, was found to differ from the rest in its infra-red spectrum. Having confirmed by various methods th at a large absorption band at 8 g. present in the spectrum of all the other diamonds, was absent in this particular one, we explored photographically the ultra-violet spectrum of all the diamonds then available, and found th at the stone which was transparent at 8 p. in the infra-red was also transparent from about X 3000 to X 2250 in the ultra-violet, the other diamonds being opaque beyond X 3000. At this stage, between two and three hundred diamonds were examined visually by means of a simple ultra-violet spectroscope with fluorescent eye-piece without another diamond transparent beyond X 3000 being found. Among other physical and optical properties examined in comparison, little difference was found between diamonds of the usual and the transparent type : their waterwhiteness, density, refractive index, dielectric constant, Raman frequency and the earlier X-ray patterns appeared the same. A difference in the crystalline condition was, however, noted, for the transparent diamond was made up of a large number of parallel laminae, and it was also more nearly isotropic when examined by polarized light than the others.

scholarly journals New Polyporphyrin Arrays with Controlled Fluorescence Obtained by Diaxial Sn(IV)-Porphyrin Phenolates Chelation with Cu2+ Cation

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 829
Author(s):  
Galina M. Mamardashvili ◽  
Dmitriy A. Lazovskiy ◽  
Ilya A. Khodov ◽  
Artem E. Efimov ◽  
Nugzar Z. Mamardashvili
Keyword(s):  
Chemical Species ◽  
Ultra Violet ◽  
X Rays ◽  
Structure And Properties ◽  
Paramagnetic Resonance ◽  
1H Nuclear Magnetic Resonance ◽  
Infra Red ◽  
Connection Type ◽  
Chelation Reaction ◽  
Electron Paramagnetic

New coordination oligomers and polymers of Sn(IV)-tetra(4-sulfonatophenyl)porphyrin have been constructed by the chelation reaction of its diaxialphenolates with Cu2+. The structure and properties of the synthesized polyporphyrin arrays were investigated by 1H Nuclear Magnetic Resonance (1H NMR), Infra Red (IR), Ultra Violet - Visible (UV-Vis) and fluorescence spectroscopy, mass spectrometry, Powder X-Rays Diffraction (PXRD), Electron Paramagnetic Resonance (EPR), thermal gravimetric, elemental analysis, and quantum chemical calculations. The results show that the diaxial coordination of bidentate organic ligands (L-tyrazine and diaminohydroquinone) leads to the quenching of the tetrapyrrole chromophore fluorescence, while the chelation of the porphyrinate diaxial complexes with Cu2+ is accompanied by an increase in the fluorescence in the organo-inorganic hybrid polymers formed. The obtained results are of particular interest to those involved in creating new ‘chemo-responsive’ (i.e., selectively interacting with other chemical species as receptors, sensors, or photocatalysts) materials, the optoelectronic properties of which can be controlled by varying the number and connection type of monomeric fragments in the polyporphyrin arrays.

Effect of chemical admixtures on the sulfate requirement of cement

1980 ◽  
Vol 7 (2) ◽  
pp. 256-263 ◽  
Author(s):  
M. A. Ward ◽  
S. M. Khalil ◽  
B. W. Langan
Keyword(s):  
Portland Cement ◽  
Initial Temperature ◽  
Precast Concrete ◽  
Steam Curing ◽  
Sulfate Content ◽  
Chemical Admixtures ◽  
Cost Of Energy ◽  
Hot Weather ◽  
The Cost ◽  
Ready Mixed Concrete

As the cost of energy and hence the cost of producing Portland cement increase, the question arises as to whether we are obtaining optimum performance from the admixtures we use. As an example, data are presented indicating that a significant improvement in strength and shrinkage can be achieved by optimizing the sulfate content of the cement for given cement–admixture combinations. It is shown that the optimum SO3 is clearly a function of the initial temperature of the concrete, particularly during the first 24 h after casting, a characteristic of considerable importance in hot weather concreting and steam curing of concrete products. It is recommended that more attention be directed towards optimizing the effectiveness of chemical admixtures in both the ready-mixed concrete and precast concrete industries.

scholarly journals Hydrogen Conversion in Nanocages

Hydrogen ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 160-206
Author(s):  
Ernest Ilisca
Keyword(s):  
Ultra Violet ◽  
Dipolar Interactions ◽  
Nuclear Spins ◽  
Reaction Heat ◽  
Thermal Methods ◽  
The Past ◽  
Hydrogen Molecules ◽  
Conversion Rates ◽  
Catalytic Sites ◽  
Infra Red

Hydrogen molecules exist in the form of two distinct isomers that can be interconverted by physical catalysis. These ortho and para forms have different thermodynamical properties. Over the last century, the catalysts developed to convert hydrogen from one form to another, in laboratories and industries, were magnetic and the interpretations relied on magnetic dipolar interactions. The variety concentration of a sample and the conversion rates induced by a catalytic action were mostly measured by thermal methods related to the diffusion of the o-p reaction heat. At the turning of the new century, the nature of the studied catalysts and the type of measures and motivations completely changed. Catalysts investigated now are non-magnetic and new spectroscopic measurements have been developed. After a fast survey of the past studies, the review details the spectroscopic methods, emphasizing their originalities, performances and refinements: how Infra-Red measurements characterize the catalytic sites and follow the conversion in real-time, Ultra-Violet irradiations explore the electronic nature of the reaction and hyper-frequencies driving the nuclear spins. The new catalysts, metallic or insulating, are detailed to display the operating electronic structure. New electromagnetic mechanisms, involving energy and momenta transfers, are discovered providing a classification frame for the newly observed reactions.

scholarly journals Study of the Absorptance of a Thin Layer of the Vanadium Dioxide

2016 ◽  
Vol 9 (48) ◽  
Author(s):  
Abderrahim Ben chaib ◽  
Zouini Mohammed ◽  
Izeddine Zorkani ◽  
Abdesselam Mdaa ◽  
Anouar Jorio
Keyword(s):  
Thin Layer ◽  
Vanadium Dioxide

scholarly journals Sustainable Retirement Living: What Matters?

2013 ◽  
Vol 1 (1) ◽  
pp. 56 ◽  
Author(s):  
Jake Barker ◽  
Bo Xia ◽  
George Zillante
Keyword(s):  
Sustainable Development ◽  
Questionnaire Survey ◽  
Energy Efficient ◽  
Energy Supply ◽  
Household Waste ◽  
Public Acceptance ◽  
Ageing Population ◽  
Cost Of Energy ◽  
The Cost ◽  
Survey Approach

There is a growing demand for sustainable retirement villages in Australia due to an increasing number of ageing population and public acceptance of sustainable development. This research aims to gain a better understanding of retirees’ understanding about sustainable retirement living and their attitudes towards sustainable developments via a questionnaire survey approach. The results showed that the current residents of retirement villages are generally very conscious of unsustainable resource consumption and would like their residences and community to be more environmentally friendly and energy efficient. The cost of energy supply is a concern to majority of respondents. However there is a certain level of concerns from residents too on the extra cost of going green in their residence. Education is required to residents about recycling household waste and how to use available facilities. A better understanding of retirees’ awareness and attitudes towards sustainability issues helps to improve the sustainable developments of retirement villages in the future.

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