JOURNAL OF RESEARCH ON MANY BODY SYSTEMS
Year:2016 | Volume:5 | Issue:10|Papers Count:6

Generalized Hubbard model was used to study the effect of uniaxial deformation of the vacancy defect in diamond. The [001] strain on the vacancy’s neighboring carbon atoms was assumed and in consequence the symmetry of crystal lowered to D2d. The results of Hubbard calculation with C70H70 cluster in the Gaussian 2003 package show that the T states (triplet spatial degenerate state) spilt to E (double spatial degenerate state) and A state (single spatial degenerate state). Also we found that the GR1 line in V0 will be changed by deformation percent of the vacancy’s neighboring carbon atoms and a little change in the ND1 line in the NV- which is in agreement with experimental results. Our results can predict the experimental results in this field.

In this paper not expensive and sensitive humidity optical sensor was fabricated based on the growth of nano and micro rods of ZnO on the optical fiber through hydrothermal method. If fiber optic sensors that work based on evanescent waves covered with nanostructures would significantly enhance the sensitivity of sensros. Nano and micro rods of ZnO was formed densly and uniformly on the optical fiber. With exserting the humidity the refractive index around the fiber will change which leads to the variation of the external light intensity. Variations of light intensity which corresponds to the humidity concentration were recorded by spectrophotometer. Response time and recover time of sensor were measured and demonstrated that the ability of sensing humidity in acceptable level (10%-100%). Also the effect of two differet light source (laser He-Ne and white LED) on the sensitivity of sensors were investigated. The structure and morphology of ZnO nano rods were studied through XRD and SEM analysis.

We have improved XPS peak shape analysis for accurate characterization of metal nanostructures intermixed with a polymer matrix. We have determined the detailed in depth distribution of cylindrical Au nanowire in polymer matrix by the analysis of a single spectrum by taking into account the electron transport phenomena corresponding to both metal and polymer components. This means that we have made a very simple and nondestructive indirect 3D XPS imaging technique for accurate inline characterization of binary component surface nanostructures including metal and polymer. This is a very promising technique which is suitable for inline quality control of such surface nanostructures.

In this paper fusion liquid-solid phase by numerical method using weighted density functional theory (MWDA), hard-sphere potential model (HS) and function (PY) by calculating total free energy of liquid metals such as sodium, magnesium and aluminum has been studid. Then we calculated the amount of density of the solid and liquid coexist using free energy graph according to density of hard-sphere fluid and solids fcc, bcc and hcp wich these results good agreement with Mont Carllo simulation results and other Previous works. Finally we study stability lattices fcc, bcc and hcp, according to their energy. Finally we study stability lattices fcc, bcc and hcp, according to their energy.

Electro spinning is a fast, simple and powerful method to synthesis fibers. In this paper, we report the results of nonconductive PVP – ethanol solution electro spinning in presence of a time-variable magnetic field. Optical microscopy results show that helical fibers would form because of Faraday Effect whereas in the absence of magnetic field fibers are spun in a random non-helical manner. Scanning electron microscopy investigations show that applying a variable magnetic field cause to the stability and uniformity of the spun fibers. In addition, results show that the fibers’ diameters are dependent on the magnetic field and frequency as well as curvature of fibers.

In this work, plasmonic bowtie nano-antennas (as two opposite nano-prisms) for enhancing the electric field and Purcell’s factor of In GaN/GaN quantum dot emitters have been designed. To this end, at first, gold, silver, copper, and aluminum bowties have been investigated. The primary results showed aluminum bowties are more suitable for low wavelength excitations near the green band. Then, the size, gap, and substrate of aluminum bowties have been examined. The results showed aluminum nano-antennas with the length of 63.6 nm, the thickness of 30 nm, top angle of 300, and gap of 20 nm, when are grown on GaN/glass as substrate, results in a Purcell; s factor of 81 with a resonance wavelength of 535 nm. Replacing the AlN/glass with GaN/glass substrate, results in a Purcell’s factor of 86.3 and resonance wavelength of 495 nm.