603 research outputs found
An efficient way to reduce losses of left-handed metamaterials
We propose a simple and effective way to reduce the losses in left-handed
metamaterials by manipulating the values of the effective parameters R, L, and
C. We investigate the role of losses of the short-wire pairs and the fishnet
structures. Increasing the effective inductance to capacitance ratio, L/C,
reduces the losses and the figure of merit can increase substantially,
especially at THz frequencies and in the optical regime
Size Dependence and Convergence of the Retrieval Parameters of Metamaterials
We study the dependence of the retrieval parameters, such as the electric
permittivity, the magnetic permeability and the index of refraction, , on
the size of the unit cell of a periodic metamaterial. The convergence of the
retrieved parameters on the number of the unit cells is also examined. We have
concentrated our studies on the so-called fishnet structure, which is the most
promising design to obtain negative at optical wavelengths. We find that as
the size of the unit cell decreases, the magnitude of the retrieved effective
parameters increases. The convergence of the effective parameters of the
fishnet as the number of the unit cells increases is demonstrated but found to
be slower than for regular split ring resonators and wires structures. This is
due to a much stronger coupling between the different unit cells in the fishnet
structure.Comment: Journal-ref and DOI adde
Barley production and soil acidity
One of the causes of reduced plant yields on acid soils is aluminium toxicity. because barley is extremely sensitive to this mineral, a project started last year to examine the influence of soil acidity on barley production in the main barley growing areas of Western Australia.
This article discusses some of the background information on the project and its aims
Mechanical behavior of irregular fibers part III : the flexural buckling behavior
Fiber buckling behavior is associated with fabric-evoked prickle, which affects clothing comfort and aesthetics. In this paper, the flexural buckling behavior of irregular or nonuniform fibers is studied using the finite element method (FEM). Fiber dimensional irregularities are simulated with sine waves of different magnitude, frequency, and initial phase. The critical buckling loads of the simulated fibers are then calculated from the FE model. The results indicate that increasing the level of irregularity will decrease the critical buckling load of fibers, but the effect of the frequency and initial phase of irregularity on fiber buckling behavior is complicated and is affected by fiber diameter and effective length
Bulk Negative Index Photonic Metamaterials for Direct Laser Writing
We show the designs of one- and two-dimensional photonic negative index
metamaterials around telecom wavelengths. Designed bulk structures are
inherently connected, which render their fabrication feasible by direct laser
writing and chemical vapor deposition.Comment: 12 pages, 4 figures, submitted to Opt. Let
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