Recently, the quantum nature in the energy transport in solar cells and light-harvesting complexes has attracted much attention as being triggered by the experimental observations. We model the light-harvesting complex (i.e., PEB50 dimer) as a quantum heat engine (QHE) and study the effect of the undamped intramolecule vibrational modes on the coherent energy-transfer process and quantum transp...

A simple model presented here is to study the thermal effect on vibration of non-homogeneous orthotropic visco-elastic rectangular plate of parabolically varying thickness having clamped boundary conditions on all the four edges. For non-homogeneity of the plate material, density is assumed to vary linearly in one direction. Using the separation of variables method, the governing differential e...

Scientists and engineers can exploit nanostructures to manipulate thermal transport in solids. This is possible because the dominant heat carriers in nonmetals – crystal vibrations (or phonons) – have characteristic lengths in the nanometer range. We review research where this approach is used and propose future research directions. For instance, concepts such as phonon filtering, correlated sc...

The value measured in the amorphous structure with the same chemical composition is often considered as a lower bound for the thermal conductivity of any material: the heat carriers are strongly scattered by disorder, and their lifetimes reach the minimum time scale of thermal vibrations. An appropriate design at the nano-scale, however, may allow one to reduce the thermal conductivity even bel...

This paper presents the analysis and preliminary design, fabrication, and measurement for mechanical vibration-isolation platforms especially designed for resonating MEMS devices including gyroscopes. Important parameters for designing isolation platforms are specified and the first platform (in designs with cascaded multiple platforms) is crucial for improving vibration-isolation performance a...

In this work, analytical solutions are provided to the nonlinear equations arising in thermal and flow-induced vibration in fluid-conveying structures using Galerkin-differential transformation method with cosine aftertreatment technique. From the analysis, it was established that increase of the length and aspect ratio of the fluid-conveying structures result in decrease the nonlinear vibratio...

During image quality testing in the third and final thermal-vacuum test of the integrated WFC3 instrument, an anomaly was discovered whereby the width and peak signal fraction of short exposure PSF images were observed to modulate for alternate exposures in a series. This behavior was traced to vibration of the UVIS shutter when its servo-control loop is enabled, which is believed to induce sma...

First-principles calculations are employed to investigate the phonon transport of BiCuOSe. Our calculations reproduce the lattice thermal conductivity of BiCuOSe. The calculated grüneisen parameter is 2.4 ~ 2.6 at room temperature, a fairly large value indicating a strong anharmonicity in BiCuOSe, which leads to its ultralow lattice thermal conductivity. The contribution to total thermal conduc...

Scientists and engineers can exploit nanostructures to manipulate thermal transport in solids. This is possible because the dominant heat carriers in nonmetals – crystal vibrations (or phonons) – have characteristic lengths in the nanometer range. We review research where this approach is used and propose future research directions. For instance, concepts such as phonon filtering, correlated sc...

The cross-plane thermal conductivity of thin films of WSe2 grown from alternating W and Se layers is as small as 0.05 watts per meter per degree kelvin at room temperature, 30 times smaller than the c-axis thermal conductivity of single-crystal WSe2 and a factor of 6 smaller than the predicted minimum thermal conductivity for this material. We attribute the ultralow thermal conductivity of thes...