Analysis of Antichiral Thermomechanical Metamaterials with Continuous Negative Thermal Expansion Properties.

Negative thermal expansion is an interesting and appealing phenomenon for various scientific and engineering applications, while rarely occurring in natural materials. Here, using a universal antichiral metamaterial model with bimetal beams or strips, a generic theory has been developed to predict magnitude of the negative thermal expansion effect from model parameters. Thermal expansivity of the metamaterial is written as an explicit function of temperature and only three design parameters: relative node size, chirality angle, and a bimetal constant.

Anomalous strain energy transformation pathways in mechanical metamaterials.

This discussion starts with a mechanics version of Parseval's energy theorem applicable to any discrete lattice material with periodic internal structure: a microtruss, grid, frame, origami or tessellation. It provides a simple relationship between the strain energy volumetric/usual and distributions in the reciprocal space. The spectral energy distribution leads directly to a spectral entropy of lattice deformation (Shannon's type), whose variance with a material coordinate represents the decrease of information about surface loads in the material interior.

[Prostate cancer prevention. the current trends].

The interest in the prostate cancer prevention is associated with high incidence and slow growth of tumor. Despite the lack of clinical guidelines for prostate cancer prevention, more and more studies are carried out dedicated to this topic. Since prostate cancer prevention requires prolonged use, the substances derived from food are seems to be the most appropriate.

Reprogramming Static Deformation Patterns in Mechanical Metamaterials.

This paper discusses an x-braced metamaterial lattice with the unusual property of exhibiting bandgaps in their deformation decay spectrum, and, hence, the capacity for reprogramming deformation patterns. The design of polarizing non-local lattice arising from the scenario of repeated zero eigenvalues of a system transfer matrix is also introduced. We develop a single mode fundamental solution for lattices with multiple degrees of freedom per node in the form of static Raleigh waves.

Semiconductor surface emitting lasers for photon pairs generation.

We study the feasibility of generating photon pairs in a resonant Vertical-Cavity Surface-Emitting Laser (VCSEL) as a result of a third-order non-linear, four wave mixing interaction. We focus on degenerate four wave mixing in the spontaneous regime where two pump photons are annihilated to create a pair of signal and idler photons. Using the methods of quantum optics, we calculate the two-photon production rate, the spectrum of the generated photons, and the signal-idler cross-correlations.