We report here highly dense and pure metallic cadmium (Cd) multifarious prismatic microcrystals (CMPMCs) fabricated by thermal decomposition of cadmium oxide (CdO) powder at 700 °C for 60 min under NH3 gas ambient inside horizontal tube furnace. CMPMCs were observed to be 1-1.5 μm in size with interesting morphologies of various cross sections such as triangular, trapezoidal, pentagonal and hexagonal etc. having solid, hollow/semi-hollow appearances. The as-synthesized CMPMCS were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Room temperature photoluminescence (PL) spectrum for Cd metal microcrystals exhibited a prominent emission band at 365 along with a shoulder peak at 404 nm. The UV main emission band is ascribed to radiative recombination of the electrons in the s, p conduction band near the Fermi surface and holes in the d bands generated under xenon light excitation whereas shoulder peak may be owing to surface oxidation effects or induced defects. This study shows the potential of CMPMCs for applications in optical devices. Based on vapour-solid (VS) process, growth mechanism for the formation of CMPMCs is also proposed and discussed briefly. 相似文献
In wireless ad hoc networks, there is no infrastructure to enforce cooperation between nodes. As a result, nodes may act selfishly when running network protocols to conserve their energy resources as much as possible. In this paper, we consider the “neighbor selection” game in which each individual node tries to selfishly choose its neighborhood such that its own energy consumption is optimized. We first focus on a simplified version of this game where nodes know their transmission power before participating in the game. After analyzing the problem, we propose a couple of distributed algorithms to find stable topologies using two kinds of global and local connectivity information. We then take into account the general case where the transmission powers are unknown variables and should be determined during the game. Finally, we evaluate the performance of the proposed algorithms through simulations. 相似文献
In recent years, due to severe environmental legislations and extended producer responsibility, leasing has been recommended as a strategy for increasing resources productivity and minimizing waste generation during consumption and product end-of-life (EOL) phase. Hence, it is essential to develop a model that can help leasing company for achieving sustainable production management. In this paper, a model is developed which optimizes the environmental and economical impact of product during leasing and its EOL phase from customers and leasing company point of view. To solve the problem, simulation-based optimization approach is investigated and the integrated mathematical and simulation model is developed for incorporating uncertainty during leasing period. Finally a case study with data from industry is used to validate the approach and potential applications of the developed model are illustrated. 相似文献
This paper overviews the dynamics of bluff body stabilized flames and describes the phenomenology of the blowoff process. The first section of the paper provides an overview of the fluid mechanics of the non-reacting and reacting bluff body wake flow. It highlights the key features of the flow (the boundary layer, separated shear layer, and wake), the flow instabilities that influence each of these features, and the influences of the flame on these instabilities. A key point from these studies is the large differences between the non-reacting wake (dominated by an absolutely unstable, sinuous instability associated with vortex shedding from the bluff body) and the reacting wake of high dilatation ratio flames. The latter are dominated by the lower intensity, convective instability of the shear layer. Very low dilatation ratio flames begin to approach the behavior of the non-reacting wake, as might be expected. 相似文献
The silver oxide nanoparticles (AgO2 ‐NPs) were synthesised using silver foil as a new precursor in wet chemical method. X‐ray diffraction analysis shows crystallographic structures of AgO2 ‐NPs with crystallite size of 35.54 nm well‐matched with standard cubic structure. Scanning electron microscopy analysis clearly shows the random distribution of spherical‐shaped nanoparticles. Energy dispersive X‐ray analysis confirmed the purity of the samples as it shows no impurity element. Fourier transforms infra‐red analysis confirmed the formation of AgO2 ‐NPs with the presence of Ag‐O‐Ag stretching bond. All the techniques also confirmed the loading of ceftriaxone drug on the surface of AgO2 ‐NPs. This study also described the effect of AgO2 ‐NPs having synergistic activity with β lactam antibiotic i.e. ceftriaxone against ESBL generating Escherichia coli (E. coli). Among isolated strains of E. coli, 60.0% were found to be ESBL producer. The synergistic activities of AgO2 ‐NPs with ceftriaxone suggest that these combinations are effective against MDR‐ESBL E. coli strains as evident by increase in zone sizes. The present study observed rise in MDR‐ESBL E. coli with polymorphism of blaCTXM and blaSHV causing UTI infections in Pakistani population. The antibiotic and AgO2 ‐NPs synergistic effect can be used as an efficient approach to combat uro‐pathogenic infections.Inspec keywords: antibacterial activity, nanofabrication, nanomedicine, drugs, nanoparticles, microorganisms, crystallites, scanning electron microscopy, silver compounds, X‐ray diffraction, X‐ray chemical analysis, Fourier transform infrared spectra, organic compounds, geneticsOther keywords: synergistic evaluation, clinical strains, silver oxide nanoparticles, silver foil, wet chemical method, X‐ray diffraction analysis, crystallographic structures, standard cubic structure, spherical‐shaped nanoparticles, energy dispersive X‐ray analysis, ceftriaxone drug, synergistic activity, ESBL producer, scanning electron microscopy, Fourier transform infrared analysis, Escherichia coli, blaSHV gene positive ESBL, crystallite size, random distribution, β lactam antibiotics, MDR‐ESBL E. coli strains, polymorphism, blaCTXM, uro‐pathogenic infections, uro‐pathogenic E. coli, AgO2相似文献
With the popularity of software-defined radio and cognitive radio-technologies in wireless communication, radio frequency devices have to adapt to changing conditions and adjust its transmitting parameters such as transmitting power, operating frequency, and modulation schemes. Thus, automatic modulation classification becomes an essential feature for such scenarios where the receiver has a little or no knowledge about the transmitter parameters. This paper presents kth nearest neighbor (KNN)-based classification of M-QAM and M-PSK modulation schemes using higher-order cumulants as input features set. Genetic programming is used to enhance the performance of the KNN classifier by creating super features from the data set. Simulation result shows improved accuracy at comparatively lower signal-to-noise ratio for all the considered modulations.
To improve the corrosion properties of TiAl6V4 alloy, TiN monolayer and Ti/TiN multilayer coatings are deposited by reactive magnetron sputtering. The phase, structure, and morphology properties are investigated by grazing‐incidence X‐ray diffraction, field‐emission scanning electron microscopy, and atomic force microscopy, respectively, and the corrosion behavior is evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization. The TiN monolayer and Ti/TiN multilayer with thickness of 1,350 and 1,410 nm have the (111) and (002) preferred orientation and crystallite size of 42.5 and 24.3 nm, respectively. Columnar growth in TiN is hindered by the Ti interlayers and no cracking is observed between the layers indicating strong adhesion. The nanostructured Ti/TiN coating forms stable surface titanium oxide which improves the corrosion resistance by approximately 80 and four times compared with TiAl6V4 alloy and TiN coating, respectively. Hindrance of the columnar structure in TiN by the Ti interlayer decreases the local corrosion rate and enhances the galvanic corrosion resistance by forming a layer on the β‐phase enriched with vanadium as well as a TiO2 stable layer. The nanostructured Ti/TiN coating demonstrates capacitive behavior with phase angles approximately ?50° and high impedance values at low frequency to be the corrosion resistance mechanism. 相似文献
Wireless Personal Communications - In this paper, we propose an architecture to implement IEEE 802.16e transmitter and receiver physical (PHY) layer on field programmable gate arrays. Several... 相似文献
In this study, we have investigated the negative magnetization of Lu0.5Sc0.5FeO3 (LSFO) ceramics in the zero-field-cooled (ZFC) mode. The negative magnetization in ZFC measurement appears below the Neél temperature (TN) in LSFO, which is probably caused by the residual negative trapping field in superconducting magnet, and is closely related to the giant coercivity in LSFO. By fitting the high-temperature paramagnetic data under nominal zero magnetic field, the negative trapping field in superconducting magnet is found to be −3.28 Oe. The giant coercivity is ascribed to the strong uniaxial magnetocrystalline anisotropy in LSFO, which can cause the strong magnetic domain wall pinning effect to limit the nucleation of reversed domains under reverse field. In addition, a switchable magnetization switching is realized in LSFO. The magnetization of LSFO can stably switch between positive and negative values when the applied magnetic field was switched between 0.5 and 3 kOe, which suggests that the LSFO samples are suitable for potential applications in magnetic storage. 相似文献