Earth's deciduous plants have a sharp order-of-magnitude increase in leaf reflectance between approximately 700 and 750 nm wavelength. This strong reflectance of Earth's vegetation suggests that surface biosignatures with sharp spectral features might be detectable in the spectrum of scattered light from a spatially unresolved extrasolar terrestrial planet. We assess the potential of Earth's st...

This paper presents a low-cost Ultra Wideband (UWB) pulse generator that can vary the pulse duration digitally by using a Step Recovery Diode (SRD), microstrip transmission lines and PIN diodes. First, a sharp edge is generated by using a SRD circuitry. Then a pulse is formed from the sharp edge through the use of transmission lines and the PIN diodes. Based on the number of transmission lines ...

Numerical results are presented for the shock-boundary layer interactions in a hypersonic flow over a sharp leading edge compression corner. In this study, a second- order Godunov type scheme based on solving a Generalized Riemann Problem (GRP) at each cell interface is used to solve thin shear layer approximation of laminar Navier-Stokes (N-S) equations. The calculated flow-field shows general...

a compact and sharp-rejection ultra-wideband (uwb) microstrip bandpass filter (bpf) is presented. the proposed filter is constructed with multiple-mode resonator (mmr) and split ring resonator (srr). moreover, proposed structure consists of two doublets parallel coupling gaps at each side of a microstrip ring. in comparison with some other filters, this structure shows a significantly wider pas...

A new approach used for image edge deduction, segmentation and normalization illumination under varying lighting conditions are presented. Edge detection refers to the process of identifying and locating sharp by applying smooth and noisy clinical technic in an image. It has favorable applications in the fields such as machine vision, pattern recognition, object recognition, motion analysis, pa...

We present a programmable acoustofluidic pump that utilizes the acoustic streaming effects generated by the oscillation of tilted sharp-edge structures. This sharp-edge-based acoustofluidic pump is capable of generating stable flow rates as high as 8 μL min(-1) (~76 Pa of pumping pressure), and it can tune flow rates across a wide range (nanoliters to microliters per minute). Along with its abi...

We show that the random number Tn of triangles in a random graph on n vertices, with a strict constraint on the total number of edges, admits an expansion Tn = an 3 + bn + Fn, where a and b are numbers, with the mean 〈Fn〉 = O(n) and the standard deviation σ(Tn) = σ(Fn) = O(n ). The presence of a ‘surface term’ bn has a significance analogous to the macroscopic surface effects of materials, and ...

The effects of uncertainties in the gas-surface interaction and intermolecular interaction models on the hypersonic boundary layer development are investigated using the non-intrusive generalized polynomial chaos method. In particular, uncertainties in the surface shear stress, normal stress, heat flux, flowfield temperature and density resulting from uncertain viscosity exponent, surface tempe...

The Gestalt law of continuity, or smoothness, is an important factor in guiding the edge grouping. In practice, however, the boundaries of many salient structures of interest may not be smooth everywhere and may contain some sharp corners. This paper presents a globally optimal edge-grouping method that can detect perceptually salient boundaries with sharp corners. In this method, a set of stra...

A novel configuration of dielectric multilayer wavelength filters for enabling sharp cut-off characteristics is proposed. By applying perturbations to the multilayer structures such as corrugation or lateral film isolation, deep optical stopbands can be created as a result of the coupling between the obliquely and horizontally propagating light waves. Numerical simulation by FDTD revealed that ...