Control of the polarization of light is highly desirable for detection of material's chirality since biomolecules have vibrational modes in the optical region. Here, we report an ultrafast tuning of pronounced circular conversion dichroism (CCD) in the mid-infrared (M-IR) region, using an achiral phase change metamaterial (PCMM). Our structure consists of an array of Au squares separated from a...

The circularly polarized luminescence (CPL) of chiral disubstituted liquid-crystalline polyacetylene (di-LCPA) can be dynamically switched and amplified from left- to right-handed CPL and vice versa through the selective transmission of CPL across a thermotropic chiral nematic liquid crystal (N*-LC) phase. By combining a chiral di-LCPA CPL-emitting film with an N*-LC cell and tuning the selecti...

Cirrus clouds are ubiquitous in the tropical tropopause region and play a major role in the Earth's climate. Any changes to cirrus abundance due to natural or anthropogenic influences must be considered to evaluate future climate change. The detailed impact of cirrus clouds on climate depends on ice particle number, size, morphology, and composition. These properties depend in turn on the nucle...

A microscopic model for the resistance drift in the phase-change memory is proposed based on the firstprinciples results on the compressed amorphous Ge2Sb2Te5. First, it is shown that the residual pressure in the phase-change memory cell can be significant due to the density change accompanying the phase transformation. Our previous first-principles calculations showed that the energy gap is re...

Current methods for inferring population structure from genetic data do not provide formal significance tests for population differentiation. We discuss an approach to studying population structure (principal components analysis) that was first applied to genetic data by Cavalli-Sforza and colleagues. We place the method on a solid statistical footing, using results from modern statistics to de...

We investigate the adiabatic evolution of a set of nondegenerate eigenstates of a parametrized Hamiltonian. Their relative phase change can be related to geometric measurable quantities that extend the familiar concept of Berry phase to the evolution of more than one state. We present several physical systems where these concepts can be applied, including an experiment on microwave cavities for...

The selection and configuration of building materials for optimal energy efficiency in a building require some assumptions and models for the thermal behavior of the utilized materials. Although the models for many materials can be considered acceptable for simulation and calculation purposes, the work for modeling the real time behavior of phase change materials is still under development. The...

Parallel tempering Monte Carlo and multihistogram methods are combined to study the phase changes of the water octamer. The heat capacity is calculated continuously from very low temperatures up to T5230 K. We find the melting temperature to be 178.5 K. In addition, a solid–solid phase change is found at 12 K. We introduce an order parameter to monitor this low temperature phase change. © 2001 ...

Efficient, cost effective, and stable high-temperature heat storage material systems are important in applications such as high-temperature industrial processes (metal processing, cement and glass manufacturing, etc.), or electricity storage using advanced adiabatic compressed air energy storage. Incorporating phase change media into heat storage systems provides an advantage of storing and rel...

A redox-reversible iron orthovanadate cathode is demonstrated for a solid oxide electrolyser with up to 100% current efficiency for steam electrolysis. The iron catalyst is grown on spinel-type electronic conductor FeV2O4 by in situ tailoring the reversible phase change of FeVO4 to Fe+FeV2O4 in a reducing atmosphere. Promising electrode performances have been obtained for a solid oxide steam el...