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Some Formulas for the Polynomials and Topological Indices of Nanostructures

. Toroidal graphenes from 4-valent tori. Bull. Chem. Soc. Jpn. 2002, 75, 487-492. 6. Diudea, M. V. Hosoya polynomial in tori. Commun. Math. Comput. Chem. 2002, 45, 109-122. 7. Diudea, M. V. Omega Polynomial in All R[8] Lattices. Iranian Journal of Mathematical Chemistry, 2010, 1(1), 69-77. 8. Soleimani, N.; Nikmehr, M. J.; Tavallaee, H. A. Theoretical study of nanostructures using topological indices. Studia Universitatis Babes- Bolyai, Chemia. 2014, 59(4), 139-148. 9. Nikmehr, M. J.; Veylaki, M.; Soleimani, N

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Synthesis and Transport Properties of Nanostructured VO2 by Mechanochemical Processing

powder and thin film of vanadium dioxide: Electrical and infrared properties. J. Phys. Chem. Solids , 62 (7), 1229-1238. Eyert, V. (2002). The metal-insulator transitions of VO 2 : A band theoretical approach. Ann. Phys. , 11 (9), 650-702. Wang, Y., Zhang, Z., Zhu, Y., Li, Z., Vajtai, R., Ci, L., Ajayan, P. M. (2008). Nanostructured VO 2 photocatalysts for hydrogen production. ACS Nano , 2 (7), 1492-1496. Bai, H., Cortie, M. B., Maaroof, A. I., Dowd, A., Kealley, C., Smith, G. B. (2009

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Fabrication and characterization of nanostructured Ba-doped BiFeO3 porous ceramics

, and its pore forming effects are quite favorable. Microporous ceramics with nanosized grains on the cell walls have attracted attention because of their unique and astonishing properties, such as high specific surface area. Nanostructured bismuth ferrite shows strong size-dependent magnetic properties [ 19 ] and has been studied for the potential use as a gas sensor for sensing ethanol and acetone [ 20 ]. Previously, an attempt was made to achieve appropriate conditions for synthesizing the single-phase bismuth ferrite by substitution of Ba²⁺ into Bi³⁺ sites [ 21

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Preparation of polyaniline nanostructures doped with different dicarboxylic acids through template-free method

Abstract

In this article nanoscaled polyanilines (PANI) were prepared based on template-free method in the presence of dicarboxylic acid dopants (e.g. D-tartaric acid, succinic acid, maleic acid and fumaric acid). The trans-cis isomerization of butenedioic acid played an important role in the formation of nanostructures from the plane-like to nanofibers, and the PANI doped with maleic acid (MA) had larger diameter, higher crystallinity and conductivity than PANI doped with fumaric acid (FA).

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Synthesis of Carbon Nanostructures by Plasma Enhanced Chemical Vapour Deposition at Atmospheric Pressure

Synthesis of Carbon Nanostructures by Plasma Enhanced Chemical Vapour Deposition at Atmospheric Pressure

Carbon nanostructures present the leading field in nanotechnology research. A wide range of chemical and physical methods was used for carbon nanostructures synthesis including arc discharges, laser ablation and chemical vapour deposition. Plasma enhanced chemical vapour deposition (PECVD) with its application in modern microelectronics industry became soon target of research in carbon nanostructures synthesis. Selection of the ideal growth process depends on the application. Most of PECVD techniques work at low pressure requiring vacuum systems. However for industrial applications it would be desirable to work at atmospheric pressure. In this article carbon nanostructures synthesis by plasma discharges working at atmospheric pressure will be reviewed.

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Nanostructured targets for TNSA laser ion acceleration

Abstract

Nanostructured targets, based on hydrogenated polymers with embedded nanostructures, were prepared as thin micrometric foils for high-intensity laser irradiation in TNSA regime to produce high-ion acceleration. Experiments were performed at the PALS facility, in Prague, by using 1315 nm wavelength, 300 ps pulse duration and an intensity of 1016 W/cm2 and at the IPPLM, in Warsaw, by using 800 nm wavelength, 40 fs pulse duration, and an intensity of 1019 W/cm2. Forward plasma diagnostic mainly uses SiC detectors and ion collectors in time of flight (TOF) configuration. At these intensities, ions can be accelerated at energies above 1 MeV per nucleon. In presence of Au nanoparticles, and/or under particular irradiation conditions, effects of resonant absorption can induce ion acceleration enhancement up to values of the order of 4 MeV per nucleon.

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Synthesis of ZnO-CuO flower-like hetero-nanostructures as volatile organic compounds (VOCs) sensor at room temperature

Abstract

ZnO-CuO flower-like hetero-nanostructures were successfully prepared by combining hydrothermal and dip coating methods. Flower-like hetero-nanostructures of ZnO-CuO were examined by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and UV-Vis. The sensing properties of ZnO-CuO flower-like hetero-nanostructures to volatile organic compounds (VOCs) were evaluated in a chamber containing acetone or isopropanol gas at room temperature. The sensitivity of ZnO-CuO flower-like hetero-nanostructures to VOCs was enhanced compared to that of pure leafage-like ZnO nanostructures. Response and recovery times were about 5 s and 6 s to 50 ppm acetone, and 10 s and 8 s to 50 ppm isopropanol, respectively. The sensing performance of ZnO-CuO flower-like hetero-nanostructures was attributed to the addition of CuO that led to formation of p-n junctions at the interface between the CuO and ZnO. In addition, the sensing mechanism was briefly discussed.

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Green synthesis and spectral analysis of surface encapsulated copper (II) oxide nanostructures

Abstract

Nanostructures of copper (II) oxide were synthesized through chemical reduction of copper (II) sulfate pentahydrate using phytochemicals present in leaf extracts of Leucas aspera. The crystalline phases and size were assessed by X-ray diffraction data analysis. From the Bragg reflection peaks, existence of monoclinic end-centered phase of copper (II) oxide along with presence of cubic primitive phase of copper (I) oxide and traces of cubic face centered lattices of zero valent copper was revealed. The three Raman active modes corresponding to CuO phase were identified in the sample with permissible merging of characteristic bands due to nanostructuring and organic capping. The surface topography measurement using field emission scanning electron microscope evidenced the occurrence of cylindrical rod shaped morphological structures along with a number of unshaped aggregates in the sample. The effective crystallite size and lattice strain were estimated from Williamson-Hall analysis of Bragg reflection data. Tauc plot analysis of UV-Vis-NIR absorption data in direct transition mode provided an estimation of band gap, viz. 1.83 eV and 2.06 eV respectively, for copper (II) oxide and copper (I) oxide. Thermal degradation study using thermogravimetric curve analysis could reveal the amount of moisture content, volatile components as well as the polymer capping over nanorods present in the sample. It could be seen that upon heating, inorganic core crystals undergo oxidation process and at temperature above 464 °C, the sample was found to be composed solely of inorganic crystallite phase of copper (II) oxide.

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FeS2 quantum dots sensitized nanostructured TiO2 solar cell: photoelectrochemical and photoinduced absorption spectroscopy studies

Abstract

Thin films of nanostructured TiO2 have been modified with FeS2 (pyrite) nano-particles by a low temperature chemical reaction of iron pentacarbonyl with sulfur in xylene. Quantum size effects are manifested by the observation of a blue shift in both absorption and photocurrent action spectra. PIA (Photoinduced absorption spectroscopy), where the excitation is provided by a square-wave modulated (on/off) monochromatic light emitting diode, is a multipurpose tool in the study of dye-sensitized solar cells. Here, PIA is used to study quantum-dot modified TiO2 nanostructured electrodes. The PIA spectra obtained give evidence for long-lived photoinduced charge separation: electrons are injected into the metal oxide and holes are left behind in the FeS2 quantum dot. Time-resolved PIA shows that recombination between electrons and holes occurs on a millisecond timescale. The Incident-Photon-to-Current Efficiency of about 23 % was obtained at 400 nm excitation. The performances of TiO2 electrodes modified with FeS2 are relatively low, which is explained by the presence of FeS2 phases other than the photoactive pyrite phase, as follows from the XRD spectrum.

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An ammonia sensor based on in situ-synthesized polyaniline nanostructures

Abstract

Nowadays, a good deal of research is focusing on the development of new analytical procedures for detection of hazardous agents, such as bacteria, harmful pollutants, toxic vapors, and many others. The majority of the research is aimed at developing new sensors and analytical equipment. This paper demonstrates a simple construction of an ammonia sensor based on commercially available electronic connectors with active elements from polyaniline. The main goal of this research is to present the simplicity of sensor manufacturing, without the need for advanced apparatus such as electropolymerization or electrospinning set-up. The active element of the proposed sensor is composed of polyaniline synthesized in situ on the surface of conductive glue. The layer of the conductive glue is a key element in this sensor as it protects the metallic pin against destruction during in situ synthesis of polyaniline (acidic and oxidizing conditions).

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