Sharif Digital Repository

Colloidal nanoparticle could be used for recognition location of tumors and cancer tissue. A simulation of molecular dynamic for colloidal silver nanoparticles (Ag NPs) based on density functional theory (DFT) potential parametrization with different sizes in 1-ethyl-3-methylimidazolium hexafluorophosphate [EMim][PF6] ionic liquid was performed. Then, using Green Kubo formalism, diffusion coefficient for Ag NPs in IL and in the gas phase was calculated. We also calculated diffusion coefficients of anions and cations for pure IL and IL in the presence of different sizes of Ag NPs at different temperatures. The findings showed that the diffusion coefficient of anions and cations increases in... 

Cu-1·5Cr alloy was successfully produced by a new method, composed of alloying via melting in a non-protected atmosphere followed by rapid cooling in a water cooled mould. The effects of deformation magnitude during T10 treatment on microstructure, electrical conductivity and hardness of alloy were also investigated. The results showed that cold work before age hardening treatment, especially in the range of 20-40% deformation, provides optimum electrical and mechanical properties, i.e. electrical conductivity of 70-85% International Annealed Copper Standard (IACS) and hardness of 160-180 HB. In addition, the cold work promotes a useful anisotropy in electrical and mechanical properties of... 

The present study provides an inverse solution and analysis on a new approach for Electrical Impedance Tomography (EIT) process as block method in EIT. In this method, it is assumed that all of the panicles of each block have the same electrical properties (electrical conductivities). This technique is used to enhance image resolution and also to improve reconstruction algorithm. Although this method has been developed for 3D objects, in this study it is assumed that the subject has a (two-dimensional) rectangular shape and is made of fixed size blocks. By considering the previous conditions and computing relationship among currents, voltages and electrical impedances of blocks, the required... 

The formation of atomic nanoclusters on suspended graphene sheets has been investigated by employing a molecular dynamics simulation at finite temperature. Our systematic study is based on temperature-dependent molecular dynamics simulations of some transition and alkali atoms on suspended graphene sheets. We find that the transition atoms aggregate and make various size nanoclusters distributed randomly on graphene surfaces. We also report that most alkali atoms make one atomic layer on graphene sheets. Interestingly, the potassium atoms almost deposit regularly on the surface at low temperature. We expect from this behavior that the electrical conductivity of a suspended graphene doped by... 

The present study shows the approach developed and employed to wastewater treatment utilizing the vermifiltration technique in a region with a population of approx. 280 people. The domestic sewage from the residential area accumulated in the septic tank was fed into the system designed based on the combination of the sand filter and the vermifilter with the optimum loading rate of 2m2 per day for 45 days. The pH, electrical conductivity, chemical oxygen demand, turbidity and nitrate concentration of wastewater were measured before and after vermitreatment for the mentioned period. The results demonstrated that the unique combination of the vermifiltration system with the sand filter was able... 

In this work, flexible thermoelectric fabrics, polyester/yarn fabrics coated with polyaniline/carbon nanotube (PANI/CNT) nanocomposite, were fabricated by sequential processing: (I) polyaniline/carbon nanotube nanocomposites preparation by a one-step in-situ polymerization and (II) dip coating of a mixture solution of CNT-doped PANI on a polyester/yarn fabric. Nanocomposites were synthesized with various CNT content (0.5, 2.5, 5, and 10 wt%) and characterized using different methods. The Seebeck coefficient and electrical conductivity measurements were used to determine their thermoelectric properties. The results revealed significant improvement in both electrical conductivity and the... 

In this investigation, application of the least square support vector machine (LSSVM) for modeling of the electrical resistivity of the magnetic Zn-Mn-S nanocrystalline semiconductor films has been described. The model has been trained based on the experimental data obtained from a published work by Sreekantha Reddy et al. The model inputs are temperature and variations in the concentrations of Zn, Mn. The results indicate that LSSVM is able to be used for accurate prediction of the electrical resistivity of the Zn-Mn-S nanocrystalline semiconductor films  

Scattering of graphene surface plasmons that are obliquely incident on a line discontinuity in graphene surface conductivity is investigated. The analysis is based on a solution of the quasi-static integral equation for surface charge density. It is shown that the reflection coefficient of the graphene plasmons reaches a minimum at a specific angle of incidence that depends on the ratio of conductivities of the two regions surrounding the discontinuity. This effect, which is similar to the well-known Brewster effect, is pronounced for abrupt discontinuities, but becomes weaker as the width of the transition region increases. The results obtained can be used for the design and analysis of... 

The high temperature superconductor thin films Cu1-xTl xBa2Ca3Cu4O12-δ (Cu1-xTlx- 1234) are post-annealed in a nitrogen atmosphere. The zero-resistivity critical temperature (Tc(R ≤ 0)) of these thin films is increased from 92.3 to 104K. The grain size is enhanced and their morphology is improved with the post-annealing. The enlargement of grain size is linked to fluctuation-induced conductivity (FIC) in the light of Aslamazov-Larkin (AL) theory. The FIC measurements have shown that the cross-over of three-dimensional (3D) to two-dimensional (2D) behaviour of fluctuations is shifted to higher temperature values with an increase of post-annealing temperature. These results have shown that the... 

We have studied the electrical and magnetic properties of normal and superconducting states of RuGd1.6Ce0.4Sr 2Cu2O10-δ (Ru-1222) system, prepared by the standard solid-state reaction technique, with applied magnetic field. The resistivity curves show that at high temperature the system is paramagnetic. At lower temperature, we can observe two magnetic transitions from paramagnetic state to anti-ferromagnetic and from anti-ferromagnetic to ferromagnetic. At room temperature the resistivity of sample shows insulating behavior and superconducting transition occurs at 45 K. Superconducting and magnetic parameters such as superconducting transition temperature Tc, magnetic transition Tirr, have... 

In this paper, the excitation of surface waves in the presence of interface charges is discussed. Interface charges affect the dispersion of surface waves, and therefore they can be used in various applications such as optical modulators, switches, sensors and filters. These waves can be superior to surface plasmon waves since they are not lossy. The lossless property is satisfied in a limited range of millimetre waves to far infrared  

In this work, we used λ-DNA to produce metallic DNA samples and we investigated the stabilization time of their impedances. This is in order to show that the DNA molecules can possibly be utilized as a frame for assembling the nanocircuits and as an electronic element as well, in nanoelectric devices. It has been shown that metallic DNA has lower stabilization time than natural DNA. As expected, it is shown that making the bundled DNA oriented, impacts their impedance stabilization. In order to find the characteristic impedance of the DNA molecules under direct current, we designed and made patterned electrodes to make electrical connections between the DNAs and the used current source. The... 

Using flake powder metallurgy (FPM) technique, combined with high pressure torsion, super high strength-ductile Cu-CNT nanocomposite with high electrical conductivity is developed. The nanocomposite with 4 vol% CNT showed high tensile strength of ~474 MPa, high electrical conductivity of ~82.5% IACS as well as appreciable ductility of ~11%. According to microstructural studies, the excellent properties of the nanocomposite are attributed to the formation of trimodal grains, high density of twin and low angle grain boundaries, improvement in CNT and Cu interfacial bonding, and appropriate distribution and maintaining the microstructure of the nanotubes in the production process. The results... 

Abstract: The effect of de-siliconization on the oxidation behavior of AISI 430 stainless steel used for solid oxide fuel cell interconnect application was investigated. De-siliconization treatment was conducted via heating steel parts in an H2 environment. The de-siliconized substrates were then coated with a Mn1.5Co1.5O4 spinel coating, using wet spray method. For comparison, a similar coating process was applied on the as-received AISI 430 stainless steel specimens. Oxidation kinetics of coated interconnects were evaluated at 700, 800 and 900 °C in air. Results showed that the de-siliconization surface treatment decreased oxidation rates, with kinetic rates (g2 cm−4 s−1) of 4.39 × 10−14... 

A nanocomposite of Ce-doped TiO2-reduced graphene oxide (CedT/RGO) was synthesized to evaluate the synergistic effects of constituents on electrical and photoelectric properties. The nanoparticles of titania and CedT were synthesized via the sol-gel method. Then, RGO was prepared using a new version derived from the Hammer's method and hydrothermal methods. Finally, CedT/RGO nanocomposite was synthesized applying hydrothermal method. The nanoparticles and nanocomposite were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray spectroscopy and elemental mapping. Then, diffuse reflectance and... 

Adult cardiomyocytes are terminally differentiated cells that result in minimal intrinsic potential for the heart to self-regenerate. The introduction of novel approaches in cardiac tissue engineering aims to repair damages from cardiovascular diseases. Recently, conductive biomaterials such as carbon- and gold-based nanomaterials, conductive polymers, and ceramics that have outstanding electrical conductivity, acceptable mechanical properties, and promoted cell-cell signaling transduction have attracted attention for use in cardiac tissue engineering. Nevertheless, comprehensive classification of conductive biomaterials from the perspective of cardiac cell function is a subject for...