Optical Properties of Al@Al2O3 Nanorod as a UV and Visible Wavelengths Plasmonic Nanostructure

AbstractAluminum as a new plasmonic material shows deep ultraviolet plasmon resonances which are broadly tunable. The use of aluminum plasmonic nanostructures offers new approaches, such as access high energy regions of the spectrum, low-cost and sustainable material. Therefore, aluminum is capable of being alternative plasmonic material compared to conventional gold and silver nanostructures. In this research, surface plasmon resonance properties of Al@Al2O3 core@shell nanorods in different dielectric environments were investigated. Using boundary element method and MNPBEM simulation package the sensitivity of aluminum plasmon resonance to the presence of Al2O3 layer, different aspect ratios and different dielectric mediums were studied. Results show that in Al nanorods with diameter of 3nm increasing length from 3 to 7nm plasmon longitudinal peak wavelength monotonously increase from 138nm to 213nm. In Al@Al2O3 nanorods with the same size and presence of 0.5nm Al2O3 oxide layer the peak wavelengths dramatically shift to higher values from 307nm to 514nm in the middle of visible region. Plasmon resonance sensitivity to medium refractive index was also investigated. Both aluminum and Al@Al2O3 nanorods exhibit red shift of longitudinal plasmon resonance wavelength by increasing refractive index from 1 to 2. Furthermore, red shift of plasmon peak wavelength by refractive index is linear in both cases. Finally results show that plasmonic response of Al@Al2O3 nanorods depend sensitively on presence of oxide layer, size and dielectric medium. As a new plasmonic material, Al@Al2O3 nanorods are capable for tremendous application due to wide ranges of plasmon resonances from deep UV to the middle of visible region

Optical Properties of Pure and Alloyed Silver-Copper Nanoparticles Embedded and Coupled in Dielectric Matrixes

AbstractIn this study by using the boundary element method, influence of various parameters on the response to electromagnetic radiation for pure and alloyed silver-copper was investigated. The results demonstrate decreasing interparticle gap from 20nm to 1nm for silver coupled nanoparticles leads to shifting the wavelength of optical extinction peak from 362nm to 393nm. Decreasing interparticle gap from 20nm to 1nm for Cu coupled nanoparticles leads to shifting the wavelength of optical extinction peak from 323nm to 336nm. By an increase in the medium refractive index of 1 to 2 the peak of optical extinction for a coupled Cu nanoparticles with 1nm gap distance the wavelength of plasmon resonance peak shifted from 336nm to 366nm and longitudinal plasmon resonance peak shifted from 498nm to 559nm. By changing the composition of an alloy of copper and silver nanoparticles with diameter of 10nm in dielectric matrix with refractive index 1.3 the wavelength of plasmon resonance peak shifted from 378nm for pure silver nanoparticles to 530nm for pure copper nanoparticles. In addition for Cu-Ag alloy coupled nanoparticles with 1nm interparticle gap, the wavelength of resonance peak shifted from 420nm for pure silver nanoparticles to 544nm for pure copper nanoparticles. In the case of embedded nanoparticles for coupled silver nanoparticles with 6nm gap distance, the wavelength of resonance peak shifted from 396nm to 409nm, and for coupled silver nanoparticles with 2nm gap distance, the wavelength of resonance peak shifted from 414nm to 430nm. Furthermore for coupled Cu nanoparticles with 2nm gap distance, the wavelength of resonance peak shifted from 575nm to 582nm. The results could be employed for plasmatic sensor design and fabrication

A Comparative Study of MSc Degree in Library and Information Science Curriculum in Selected Countries and Suggesting Up-to-date Courses with Medical Orientation

Introduction: The goal of this study was the comparative review of MSc syllabus in librarianship and information science in selected countries and presentation of an updated medical curriculum. Methods:  This applied research is of descriptive type reviewing the websites of universities using Delphi technique, which was conducted in two phases with checklist and questionnaire as data collection tools. In the first phase, the curricula of selected universities were collected. In the second phase, the summarized curricula were sent to faculty members of Department of Library and Information Science at MOHME in the form of a questionnaire in two rounds of Delphi. Results: The results indicated that 98% of the professors participating in Delphi agreed to update the curriculum. Moreover, majors such as advanced scientometrics, familiarity with evidence-based medicine and its databases, clinical librarianship, advanced health research methodology, and familiarity with the basic concepts of source finder, and crucial indicators in evaluating information resources were their recommended majors to be included in the suggested syllabus in addition to those extracted from universities’ websites, which were subject to survey by professors in the second round.  Conclusion: The findings of this research suggest that the views of professors participating in Delphi on curricula were largely aligned with those extracted from websites of the universities under study. Finally, the proposed syllabus was designed considering the review results of curricula and opinions of faculty members. The findings of this thesis can be a guide for curriculum planners at the Ministry of Health and Medical Education

Early and late preventive effect of Nigella sativa on the bleomycin-induced pulmonary fibrosis in rats: An experimental study

Objective: Pulmonary fibhrosis is a disease of the connective tissues in the respiratory system. Nigella sativa has been used for the treatment of pulmonary diseases like asthma. This study investigated the early and late preventive effect of methanolic extract of N. sativa on a bleomycin- induced pulmonary fibrosis model. Materials and Methods: This study was carried out using 52 rats. Pulmonary fibrosis was induced by a single endotracheal injection of bleomycin (5 mg/kg). Extract of N. sativa (500 mg/kg per day) or methylprednisolone succinate (4 mg/kg per day) was injected intraperitoneally in two periods (i.e. days 1-14 as early preventive group and days 15-28 days as late preventive group). The lung tissues were histologically examined at the end of each period and inspected for the amount of hydroxyproline and biomarkers of oxidative stress. Results: The pulmonary inflammation and fibrosis were significantly decreased in groups treated with methylprednisolone and N. sativa extract compared to bleomycin group in both early and late prevention groups (

The Effects of Surface Oxidation and Interparticle Coupling on Surface Plasmon Resonance Properties of Aluminum Nanoparticles as a UV Plasmonic Material

AbstractAluminum as a new plasmonic material is of great significance and can be used in array-based chemical and biological sensors instead of silver and gold with lower cost and more amenable manufacturing. It is vital to prevent oxidation and material degradation, in order to improve the performance and sensitivity of aluminum based surface plasmon resonance (SPR) devices. Aluminum nanoparticles passivate by forming the surrounding oxide layer. In this research, SPR properties of aluminum nanoparticles in different dielectric environments were investigated. Using boundary element method and MNPBEM simulation package the sensitivity of aluminum plasmon resonance to the presence of surrounding oxide layer, two nanoparticle coupling and different dielectric mediums were studied. Results show that in core-shell nanoparticles SPR peak position shifts from 170nm to 206nm by increasing shell thickness from 1 to 5nm. In coupled Al nanoparticles by decreasing the gap distance between the particles from 20 to 0nm the SPR longitudinal peak wavelength redshifted from 137nm to 167nm. Finally we study the effect of different embedding medium refractive indexes. Increasing dielectric matrix refractive index from 1 to 2 leads to redshift in SPR peak wavelength from 154nm to 202nm. Furthermore, enhancement of SPR peak position by refractive index is linear. In conclusion, the results show that aluminum can be used as a suitable substitution of conventional plasmonic materials especially for UV-plasmonic applications

Characterization of Al-CNT Composite Nanoparticles Synthesized by Electrical Explosion of Wire in Acetone

In this study, electrical wire explosion has been used to produce aluminum carbon nanotube (Al-CNT) nanocomposite particles in acetone medium. In order to synthesize Al-CNT nanocomposites, initially, CNTs were ultrasonically dispersed. Then, aluminum wire was exploded in this medium. Synthesized samples were characterized by Fourier Transform Infrared (FTIR) spectroscopy and Transmission Electron Microscopy (TEM) methods. The results exhibited formation of spherical nanoparticles in the medium. The average diameter of nanoparticles was 4 nm. Moreover, attained nanoparticles remained stable in acetone. Results revealed a good interaction between aluminum nanoparticles and CNTs in this medium. It is concluded that acetone is a suitable medium for synthesizing Al-CNT nanocomposite as appropriate dispersion of Al-CNT nanoparticles can be achieved in this medium

Electromagnetism Mechanism for Enhancing the Refueling Cycle Length of a WWER-1000

Increasing the operation cycle length can be an important goal in the fuel reload design of a nuclear reactor core. In this research paper, a new optimization approach, electromagnetism mechanism (EM), is applied to the fuel arrangement design of the Bushehr WWER-1000 core. For this purpose, a neutronic solver has been developed for calculating the required parameters during the reload cycle of the reactor. In this package, two modules have been linked, including PARCS v2.7 and WIMS-5B codes, integrated in a solver for using in the fuel arrangement optimization operation. The first results of the prepared package, along with the cycle for the original pattern of Bushehr WWER-1000, are compared and verified according to the Final Safety Analysis Report and then the results of exploited EM linked with Purdue Advanced Reactor Core Simulator (PARCS) and Winfrith Improved Multigroup Scheme (WIMS) codes are reported for the loading pattern optimization. Totally, the numerical results of our loading pattern optimization indicate the power of the EM for this problem and also show the effective improvement of desired parameters for the gained semi-optimized core pattern in comparison to the designer scheme