The thermal buckling properties of double-walled carbon nanotubes (DWCNTs) are studied using nonlocal Timoshenko beam model, including the effects of transverse shear deformation and rotary inertia. The DWCNTs are considered as two nanotube shells coupled through the van der Waals interaction between them. The geometric nonlinearity is taken into account, which arises from the mid-plane stretching. Considering the small-scale effects, the governing equilibrium equations are derived and the critical
buckling temperatures under uniform temperature rise are obtained. The results show that the critical buckling temperature can be overestimated by the local beam model if the nonlocal effect is overlooked for long nanotubes. In addition, the effect of shear deformation and rotary inertia on the buckling temperature is more obvious for the higher-order modes. The investigation of the thermal buckling properties of DWCNTs may be used as a useful reference for the application and the design of nanostructures in which DWCNTs act as basic elements.
Abdelouahed Tounsi: Laboratoire des Materiaux et Hydrologie, Universite de Sidi Bel Abbes, BP 89 Cite Ben M\'hidi, 22000 Sidi Bel Abbes, Algeria; Departement de Genie Civil, Faculte de Technologie, Universite de Sidi Bel Abbes, Algeria
Soumia Benguediab: Laboratoire des Materiaux et Hydrologie, Universite de Sidi Bel Abbes, BP 89 Cite Ben M\'hidi, 22000 Sidi Bel Abbes, Algeria
El Abbas Adda Bedia: Laboratoire des Materiaux et Hydrologie, Universite de Sidi Bel Abbes, BP 89 Cite Ben M\'hidi, 22000 Sidi Bel Abbes, Algeria
Abdelwahed Semmah: Universite de Sidi Bel Abbes, Departement de physique, BP 89 Cite Ben M\'hidi, 22000 Sidi Bel Abbes, Algeria
Mohamed Zidour: Laboratoire des Materiaux et Hydrologie, Universite de Sidi Bel Abbes, BP 89 Cite Ben M\'hidi, 22000 Sidi Bel Abbes, Algeria; Universite Ibn Khaldoun, BP 78 Zaaroura, 14000 Tiaret, Algerie
Carbon nanotube characterized by additional inductive effect as compared with the traditional conductors like copper wires of the same size. Consequently, carbon nanotubes have high characteristic impedance and slow wave propagation in comparison with traditional conductors. Due to these characteristics, carbon nanotubes can be used as antenna. In view of this, we describe and review the present
research progress on carbon nanotube antennas. We present different analysis models and results which are developed to investigate the characteristics of CNT antennas. Then we conclude by summarizing the characteristics of CNT antennas and specifying the operating frequency limit.
carbon nanotubes; RF circuit model; dynamic conductivity of SWCNT dipole antennas; optical antenna
Sh.G. El-sherbiny: Department of Electronics and Electrical Communication, Faculty of Electronics Engineering, Menoufia University, Menouf, 32952, Egypt; Electrical Engineering Department, Faculty of Engineering, Kferelsheikh University, Egypt
S. Wageh: Physics & Engineering Mathematics Department, Faculty of Electronic Engineering, Menoufia University,
Menouf, 32952, Egypt
S.M. Elhalafawy and A.A. Sharshar: Department of Electronics and Electrical Communication, Faculty of Electronics Engineering, Menoufia University, Menouf, 32952, Egypt
The conversion of mechanical energy into electrical energy at nanoscale using piezoelectric nanowire arrays has been in detail shown by deflection of nanowires. Recently it has performed an analytical model, both at classical and at quantum level, for describing the most important quantities concerning transport phenomena; the model predicts interesting peculiarities, as high initial charge diffusion in nanodevices constituting by nanowires and permits also in particular to deduce interesting informations about the devices sensitivity, focusing on the correlation between sensitivity and high initial diffusivity of these materials at nanometric level.
theoretical modelling; transport processes; nanophysics; nanodevices; nanosensoristics; diffusion
Paolo Di Sia: Free University of Bozen-Bolzano - Piazzetta dell\' Universita 1, I-39031 Bruneck-Brunico (BK), Italy
Cockroach (Periplaneta americana) broth has been employed to assess its potential as a candidate source animal tissue for the synthesis of gold nanoparticles. The synthesis is performed akin to room temperature in the laboratory ambience. X-ray and transmission electron microscopy analyses are performed to ascertain the formation of nanoparticles. The synthesis of nanoparticles might have resulted due to the activity of chitin, metallothioneine and tropomyosin. A possible involved mechanism for the
biosynthesis of nanoparticles has also been proposed. This work further indicates that the animal wastes too can effectively participate in nano-transformations thereby helping in controlling the environmental pollution and subsequently the different diseases.
nanobiotechnology; biological synthesis; nano gold; nanoparticles; cockroach
Anal K. Jha: Aryabhatta Centre for Nanoscience and Nanotechnology, Aryabhatta Knowledge University, Patna 800 001, India
K. Prasad: University Department of Physics, T.M. Bhagalpur University, Bhagalpur 812 007, India
Zinc oxide (ZnO) is a unique semiconductor material that exhibits numerous useful properties for dye-sensitized solar cells (DSSCs) and other applications. Various thin-film growth techniques have been used to produce nanowires, nanorods, nanotubes, nanotips, nanosheets, nanobelts and terapods of ZnO. These unique nanostructures unambiguously demonstrate that ZnO probably has the richest family of
nanostructures among all materials, both in structures and in properties. The nanostructures could have novel applications in solar cells, optoelectronics, sensors, transducers and biomedical sciences. This article reviews
the various nanostructures of ZnO grown by various techniques and their application in DSSCs. The application of ZnO nanowires, nanorods in DSSCs became outstanding, providing a direct pathway to the anode for photo-generated electrons thereby suppressing carrier recombination. This is a novel characteristic which increases the efficiency of ZnO based dye-sensitized solar cells.
semiconductor; nanostructures; Zinc Oxide; recombination; optoelectronics
M.D. Tyona: Department of Physics, Benue State University, Makurdi, Nigeria
R.U. Osujia and F.I. Ezema: Department of Physics and Astronomy, University of Nigeria, Nsukka, Nigeria
ZnO nanostructures of rod-like, faceted bar, cup-end bars, and spindle shaped morphologies could be grown by a low power ultrasonic synthesis process. pH of the reaction mixture seems to plays an important role for defining the final morphology of ZnO nanostructures. While the solution pH as low as 7 produces long, uniform rod-like nanostructures of mixed phase (ZnO and Zn(OH)2), higher pH of the reaction mixture produces ZnO nanostructures of different morphologies in pure hexagonal wurtzite phase.
pH of the reaction as high as 10 produces bar shaped uniform nanostructures with lower specific surface area
and lower surface and lattice defects, reducing the defect emissions of ZnO in the visible region of their photoluminescence spectra.
ZnO; nanostructure; ultrasound synthesis; morphology control; optical properties
N. Morales-Flores, R. Galeazzi, E. Rosendo, T. Diaz: Centro de Investigacion en Dispositivos Semiconductores, ICUAP, Benemerita Universidad Autonoma de Puebla, Puebla, Pue. 72570, Mexico
S. Velumani: Department of Electrical Engineering (SEES), Centro de Investigación y de Estudios Avanzados del IPN,
Av. Instituto Politécnico Nacional # 2508, Col. San Pedro Zacatenco, 07360 Mexico D.F., Mexico
U. Pal: Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apdo. Postal J-48, Puebla, Pue. 72570, Mexico