Despite the superb intrinsic properties of carbon nanotube mechanical resonators, the quality factors at room temperature are 1,000 or less, even in vacuum, which is much lower than that of mechanical resonators fabricated using a top-down approach. This study demonstrates the improvement of the quality factor and the control of nonlinearity of the mechanical resonance of the cantilevered nanot...

Polymer microring resonators for low-noise, wideband ultrasound detection are presented. Using a nanoimprinting technique, we fabricated polymer microring resonators with a quality factor of 6000 resulting in high sensitivity to ultrasound. A noise-equivalent pressure of 0.23 kPa over 1-75 MHz and a detection bandwidth of over 90 MHz at -3 dB were measured. These results demonstrate the potenti...

In this report, we investigate a photonic crystal circular-shaped microcavity (removing seven air holes) sustaining whispering-gallery mode (WGM) by shifting the 12 nearest air holes according to the concept of cavity-shaping in micro-disk and micro-gear lasers. The WGM modal characteristics are investigated by three-dimensional (3D) finite-difference time-domain (FDTD) simulations. From well-f...

This paper presents a new package cohesion metric (CohP), which is based on the properties of elements of a package and dependencies with in the package elements. The proposed metric has been validated theoretically against Briand properties as well as empirically using packages taken from two open source software systems. An attempt has also been made to present a positive Spearman correlation...

Refractive index sensitivity of guided resonances in photonic crystal slabs is analyzed. We show that modal properties of guided resonances strongly affect spectral sensitivity and quality factors, resulting in substantial enhancement of refractive index sensitivity. A three-fold spectral sensitivity enhancement is demonstrated for suspended slab designs, in contrast to designs with a slab rest...

We present an analytical model and numerical experiments to describe optimal bistable switching in a nonlinear photonic crystal system. It is proved that only three parameters are needed to characterize a bistable switch: the resonant frequency omega(res), the quality factor Q, and parameter kappa that measures nonlinear "feedback strength." A photonic crystal enables the device to operate in s...

We report on lasing at room temperature and at telecommunications wavelength from photonic crystal nanocavities based on InAsP/InP quantum dots. Such laser cavities with a small modal volume and high quality factor display a high spontaneous emission coupling factor (beta). Lasing is confirmed by measuring the second-order autocorrelation function. A smooth transition from chaotic to coherent e...

The evolution of the intensity profile of transversely excited atmospheric CO2 laser pulses is investigated within the intensity moment formalism. The beam quality factor M2 is used to study the mode evolution. Attention is focused on the influence of both the gas mixture (N2 :CO2 :He) and the diameter of an intracavity diaphragm placed to attenuate higher-order modes. The degree of accuracy th...

In order to clarify whether the effects of neutrons on mammalian cells are qualitatively different from those of X or gamma-rays, L cells were irradiated with D-T neutrons and 180 kvp X-rays, singly or combined. From analysis of dose response curves, it is concluded that cell killing mechanism of neutrons is not the same as that of X-ray, but there is something common in part between them. RBE ...

Evaluation and monitoring of the cancer risk from space radiation exposure is a crucial requirement for the success of long-term space missions. One important task in the risk calculation is to properly weigh the various components of space radiation dose according to their assumed contribution to the cancer risk relative to the risk associated with radiation of low ionization density. Currentl...