The use of hollow-core photonic crystal fibres as biological sensors

Abstract

Dislocation and grain-boundary processes contribute significantly to plastic behaviour in polycrystalline metals, but a full understanding of the interaction between these processes and their influence on plastic response has yet to be achieved. The coupled atomistic discrete-dislocation method is used to study edge dislocation pile-ups interacting with a 11-1 1 3 symmetric tilt boundary in Al at zero temperature under various loading conditions. Nucleation of grainboundary dislocations (GBDs) at the dislocation/grain-boundary intersection is the dominant mechanism of deformation. Dislocation pile-ups modify both the stress state and the residual defects at the intersection, the latter due to multiple dislocation absorption into the boundary, and so change the local grain-boundary/dislocation interaction phenomena as compared with cases with a single dislocation. The deformation is irreversible upon unloading and reverse loading if multiple lattice dislocations absorb into the boundary and damage in the form of microvoids and loss of crystalline structure accumulates around the intersection. Based on these results, the criteria for dislocation transmission formulated by Lee, Robertson and Birnbaum are extended to include the influences of grain-boundary normal stress, shear stress on the leading pile-up dislocation and minimization of step height at the intersection. Two possible yield loci for the onset of GBD nucleation versus compressive stress and relevant shear stresses are derived from the simulations. These results, and similar studies on other boundaries and dislocation characters, guide the formulation of continuum constitutive behaviours for use in discrete-dislocation or strain-gradient plasticity modelling.

Photonic crystal fibers for food quality analysis

“…The presence of the absorbers determines the attenuation of transmission maxima within the certain wavelength or wavelength range. [3][4][5][6].…”

“…There is a strict dependence of PCF transmission properties on spectral properties of the medium, filling up the internal channels of the fiber. In [4] it is shown, that change of optical parameters of the medium, e.g. refractive index, scattering and absorption coefficients, induces predictable transformation of PCF transmission spectrum.…”

Photonic Crystal Waveguide Biosensor

“…1 The selective detection of antibodies in a PCW was also realized. 1,6 Recent experiments provided by our research group 1,6,7 revealed that position of photonic bandgap of a hollow PCW are largely a®ected by the refractive index (RI) of the medium,¯lling the space in the hollow core and the channels of the cladding. The RI change induces a predictable transformation of PCW transmission spectrum.…”

“…The RI change induces a predictable transformation of PCW transmission spectrum. 1,6,7 The RI n c of a medium inside a hollow core determines the wavelengths of high transmission of the optical radiation through the waveguide. Transmission bands are shifting to shorter wavelengths as RI increases.…”

Blood typing using microstructured waveguide smart cuvette

“…[1][2][3][4][5] The basic advantages include a high sensitivity, short response time, and small size. [1][2][3][4][5] The basic advantages include a high sensitivity, short response time, and small size.…”