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Redefined Zagreb indices of Some Nano Structures

Zagreb index was also independently defined by Mansour and Song [ 15 ]. Moreover, the generalized version was presented in [ 23 ]. There have been many advances in Wiener index, Szeged index, PI index, and other degree-based or distance-based indices of molecular graphs, while the study of the redefined Zagreb indices of nano structures has been largely limited. Furthermore, nanotube, nanostar, polyomino chain and benzenoid series are critical and widespread molecular structures which have been widely applied in medical science, chemical engineering and

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Information Support System for Technology of Applying the Multi-Component Nano-Structured Protective Coatings

Information Support System for Technology of Applying the Multi-Component Nano-Structured Protective Coatings

The given article considers the process of arranging informational support in carrying out experiments on applying the nanostructured protective covering on different materials. For nano-coverings coating, there is used special plant, which is given different modes of performance. For accounting all parameters and for accumulating the data, which characterize the results of the experiments, there is suggested an information system which employs the database designed for these purposes. The authors suggest an approach to defining the main requirements and functions of an information system on the basis of functional simulation and consider the issues of its realization. This information system also allows processing the results of the experiments with the use of statistical methods. The analytical module of the information system is supposed for solving the tasks of determining the thickness of covering depending on the specified mode of plant operation (pressure, voltage, current); it is also employed for determining what operation mode is required for receiving the covering with certain designated properties and parameters. Consequently, the task of scientific prognostication of the covering properties is solved.

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Structural, morphological, optical and diode properties of chemical bath deposited nano-structured CdS thin films using EDTA as a complexing agent

Abstract

CdS thin films with (1 1 1) orientation were prepared by chemical bath deposition technique at 80±5 °C using the reaction between NH4OH, CdCl2 and CS(NH2)2. The influence of annealing temperature varying from 150 °C to 250 °C was studied. X-ray diffraction studies revealed that the films are polycrystalline in nature with cubic structure. Various parameters, such as dislocation density, stress and strain, were also evaluated. SEM analysis indicated uniformly distributed nano-structured spherically shaped grains and net like morphology. Optical transmittance study showed the wide transmittance band and absence of absorption in the entire visible region. I-V characterization of p-Si/n-CdS diode and photoluminescence studies were also carried out for the CdS films.

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Five-Sided Mechanism, Determination of Acceleration

Abstract

The aim of this paper is the presentation of the general form of the constraint equations necessary to calculate the accelerations occuring on a five sided spatial mechanism. Using these equations the computing of the accelerations for any part of any plain or spatial mechanism will be possible.

The constraint equations of the acceleration are obtained by computing the time derivatives of the velocity equations (which in general form are given by [1] and [2]) followed by the correspondent grouping of the unknowns.

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A Short Review of The Latest Developments in The Science of Thermoelectric Materials

Abstract

This research work is still considered as a theoretical reference material for transmitting the important role that thermoelectric materials play in evolving reality of our world. In this update, a brief reminder of the basics behind thermoelectric materials is provided, followed by some of the most recent developments, whether successful or not, in the attempt to create new more efficient materials for heat recovery within the coming years. One of the approaches deals with an innovative way to produce an already existing base material for thermoelectric application, whilst the other approaches describe new possibilities that were attempts to reach a higher dimensional figure of merit zT.

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Thallium I phenylsuccinic acid coordination polymer as precursor for preparation of thallium (III) oxide nano structures by direct thermal decomposition

Abstract

A new thallium (I) coordination polymer [Tl(PsucH)]n (PsucH = phenylsuccinic acid) has been synthesized and characterized by single crystal X-Ray analysis, elemental analysis and IR spectroscopy. The single crystal X-Ray analysis shows that this polymer is 2-D along a axis. Flower-like nanostructure thallium (III) oxide, Tl2O3 has been prepared by direct thermal decomposition of thallium (I) coordination polymer. The nanostructure was characterized by scanning electron microscopy (SEM), X-Ray powder diffraction (XRD) and IR spectroscopy. The thermal stability of the Tl2O3 nanostructure was studied by thermal gravimetric analysis and differential thermal analysis (TGA /DTA) too.

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Influence of aluminium concentration in Zn0:9V0:1O nanoparticles on structural and optical properties

Abstract

The (V,Al) co-doped ZnO nano-structured powders (Zn0.9-xV0.1AlxO, where x = 0.02, 0.03 and 0.04) were synthesized via the sol-gel technique and their structural and optical properties were investigated. The effect of Al concentration on the structural and optical properties of the Zn0.9-xV0.1AlxO nanopowders was studied using various techniques. The XRD patterns indicate that the samples have a polycrystalline wurtzite structure. The crystallite size increases with increasing the Al content and lies in the range of 23 to 30 nm. The lattice strain, estimated by the Stokes-Wilson equation, decreases when Al content increases. SEM and TEM micrographs show that Zn0.9-xV0.1AlxO powders are the agglomeration of nanoparticles having spherical and hexagonal shapes with dimensions ranging from 20 to 30 nm. FT-IR spectra show a distinct absorption peak at about 500 cm-1 for ZnO stretching modes and other peaks related to OH and H2O bands. Raman spectra confirm the wurtzite structure of the Zn0.9-xV0.1AlxO nanoparticles. The direct band gaps of the synthesized Zn0.9-xV0.1AlxO nanopowders, estimated from the Brus equation and the crystallite sizes deduced from XRD, are around 3.308 eV. The decomposition process of the dried gel system was investigated by thermal gravimetric analysis (TGA).

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Structure and Electrochemical Characteristics of LiFePO4 as Cathode Material for Lithium-Ion Batteries

Structure and Electrochemical Characteristics of LiFePO4 as Cathode Material for Lithium-Ion Batteries

To prepare cathode material for lithium batteries, LiFePO4 powder was sputtered using an RF magnetron. Thin LiFePO4 films were obtained on different ~1000 nm thick substrates. The compositional and morphological examination of these films by SEM has shown that on a silicon substrate the annealed nano-crystalline thin film of LiFePO4 material condenses in larger monocrystals (with thin film disappearance), while such a film on the stainless steel substrate coalesces in a uniform nano-structured layer after annealing. As shown by the energy-dispersive X-ray analysis, the annealed film consists of phosphorus, iron, and oxygen in the ratio corresponding to the stoichiometric LiFePO4. Cyclic voltammograms of the LiFePO4 thin layer were obtained with typical red-ox reaction peaks characterizing the electrochemical lithium insertion/extraction reactions in LiFePO4. The obtained thin films have a relatively high charge capacity of 127 mAh g-1.

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Enhancement of XPS surface sensitivity in nanocrystalline material

References Tougaard, S. (2005). XPS for Quantitative Analysis of Surface Nano-structures. Microsc. Microanal. 11(2), 676-677. DOI:10.1017/S1431927605500229. Jablonski, A. & Powell, C. J. (2004). Electron effective attenuation lengths in electron spectroscopies, J. Alloy. Compd. 362, 26-32. DOI:10.1016/S0925-8388(03)00558-9. Gunter, P. L. J. (1992). Evaluation of take-off-angle-dependent XPS for determining the thickness of passivation layers on aluminium and silicon. Surf

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The Impact Of Surface Shape Of Chip-Breaker On Machined Surface

.: Effect of cutting speed and feed on deep drilling. Applied Mechanics and Materials, Vol. 693, p. 388-393. 2014 [6] Stancekova, D. Semcer, J., Holubjak, J., Drbul, M.: Machinability of nano-structured biomaterials for dental implants. Communication - Komunikacie. Vol. 16, No. 3A. p. 96-100. 2014 [7] Cep, R., Janasek, A., Cepova, L., Petru, J., Hlavaty, I., Car, Z., Hatala, M. (2013) Experimental testing of exchangeable cutting inserts cutting ability. In Technical Gazette 20 (1), pp. 21-26. ISSN: 1330-3651 [8] Novakova, J., Petrkovska, L., Brychta, J

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