387 research outputs found
Supplier Selection Model Based on D Numbers and Transformation Function
Selecting reasonable suppliers can effectively improve the efficiency of enterprise supply chain management. Among them, expert evaluation is an important part of supplier selection problem, but the uncertainty, fuzziness and incompleteness of expert opinions make supplier selection problem difficult to solve. In order to systematically and effectively solve the uncertainty, ambiguity and incompleteness in supplier selection problem, this paper presents a new supplier selection method based on D numbers and transformation function. First, fuzzy preference relation is generated based on the decision matrix of pairwise comparisons given by experts. D numbers which can effectively deal with uncertain information extend fuzzy preference relation (D matrix). Second, the D matrix is converted into a crisp matrix form based on the integration representation of D numbers according to different situations whether or not the information in D matrix is complete. Third, the crisp matrix is converted into judgement matrix by using the transformation functions. Finally, analytic hierarchy process (AHP) method is applied based on the judgment matrix to give a priority weights for decision making. Three numerical examples and application of the supplier selection are used to show the feasibility and effectiveness of the proposed method
Full Hydrodynamic Model of Nonlinear Electromagnetic Response in Metallic Metamaterials
Applications of metallic metamaterials have generated significant interest in
recent years. Electromagnetic behavior of metamaterials in the optical range is
usually characterized by a local-linear response. In this article, we develop a
finite-difference time-domain (FDTD) solution of the hydrodynamic model that
describes a free electron gas in metals. Extending beyond the local-linear
response, the hydrodynamic model enables numerical investigation of nonlocal
and nonlinear interactions between electromagnetic waves and metallic
metamaterials. By explicitly imposing the current continuity constraint, the
proposed model is solved in a self-consistent manner. Charge, energy and
angular momentum conservation laws of high-order harmonic generation have been
demonstrated for the first time by the Maxwell-hydrodynamic FDTD model. The
model yields nonlinear optical responses for complex metallic metamaterials
irradiated by a variety of waveforms. Consequently, the multiphysics model
opens up unique opportunities for characterizing and designing nonlinear
nanodevices.Comment: 11 pages, 14 figure
Mixing of spin and orbital angular momenta via second-harmonic generation in plasmonic and dielectric chiral nanostructures
We present a theoretical study of the characteristics of the nonlinear
spin-orbital angular momentum coupling induced by second-harmonic generation in
plasmonic and dielectric nanostructures made of centrosymmetric materials. In
particular, the connection between the phase singularities and polarization
helicities in the longitudinal components of the fundamental and
second-harmonic optical fields and the scatterer symmetry properties are
discussed. By in-depth comparison between the interaction of structured optical
beams with plasmonic and dielectric nanostructures, we have found that
all-dielectric and plasmonic nanostructures that exhibit magnetic and electric
resonances have comparable second-harmonic conversion efficiency. In addition,
mechanisms for second-harmonic enhancement for single and chiral clusters of
scatterers are unveiled and the relationships between the content of optical
angular momentum of the incident optical beams and the enhancement of nonlinear
light scattering is discussed. In particular, we formulate a general angular
momenta conservation law for the nonlinear spin-orbital angular momentum
interaction, which includes the quasi-angular-momentum of chiral structures
with different-order rotational symmetry. As a key conclusion of our study
relevant to nanophotonics, we argue that all-dielectric nanostructures provide
a more suitable platform to investigate experimentally the nonlinear
interaction between spin and orbital angular momenta, as compared to plasmonic
ones, chiefly due to their narrower resonance peaks, lower intrinsic losses,
and higher sustainable optical power
Experimental observation of superscattering
Superscattering, induced by degenerate resonances, breaks the fundamental
single-channel limit of scattering cross section of subwavelength structures;
in principle, an arbitrarily large total cross section can be achieved via
superscattering. It thus provides a unique way to strengthen the light-matter
interaction at the subwavelength scale, and has many potential applications in
sensing, energy harvesting, bio-imaging (such as magnetic resonance imaging),
communication and optoelectronics. However, the experimental demonstration of
superscattering remains an open challenge due to its vulnerability to
structural imperfections and intrinsic material losses. Here we report the
first experimental evidence for superscattering, by demonstrating the
superscattering simultaneously in two different frequency regimes through both
the far-field and near-field measurements. The underlying mechanism for the
observed superscattering is the degenerate resonances of confined surface
waves, by utilizing a subwavelength metasurface-based multilayer structure. Our
work paves the way towards practical applications based on superscattering
Induction of zinc metallothionein by calcium ionophore in vivo and in vitro
AbstractThe calcium ionophore, A23187, can induce rat hepatic metallothionein (MT) when administered in vivo (5.8-fold, 5.0 μM, 11 h) and rat hepatocyte MT when administered in vitro (10.70-fold, 1.0 μM, 24 h). Several rat hepatoma cell lines (2M, 4.55-fold; JM2, 12.29-fold; EC3, 14.12-fold; HTC, 7.99-fold) and a normal rat liver cell line (Clone 9, 39.67-fold) were tested for their inducibility of MT mRNA by Cd2+ (10 μM, 8 h). Quantitatively, JM2 and 2M made the most MT mRNA, while HTC made the least. A23187 (0.1–7.0 μM) was studied as an inducer of MT mRNA in these cell lines (except for HTC) and in HeLa. A variety of responses and tolerances were seen with inductions ranging up to 32.11-fold. Quantitatively, the best responding cell lines were EC3 and 2M. A combination induction experiment, using TPA, a protein kinase C activator, and A23187 in EC3 cells revealed an additive effect of the two inducers on MT mRNA levels: TPA (10 nM), 11.71-fold; A23187 (3.0μM), 6.71-fold; and TPA + A23187, 20.00-fold. These studies have implicated perturbations in cytosolic calcium ion concentrations, caused by the ionophore A23187, as being involved in the complicated signaling systems which can lead to induction of MT mRNA and protein
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