Photon-counting x-ray detectors with pulse-height analysis provide spectral information that may improve material decomposition and contrast-to-noise ratio (CNR) in CT images. The number of energy measurements that can be acquired simultaneously on a detector pixel is equal to the number of comparator channels. Some spectral CT designs have a limited number of comparator channels, due to the co...

For time-domain modeling based on the acoustic wave equation, spectral methods have recently demonstrated promise. This letter presents an extension of a spectral domain decomposition approach, previously used to solve the lossless linear wave equation, which accommodates frequency-dependent atmospheric attenuation and assignment of arbitrary dispersion relations. Frequency-dependence is straig...

the potential energy hyper surfaces (fes) of the unimolecular rearrangements of a) nitromethane itei totrans acknitromethane b) nitrometharie (/) to methyl nitrite (3) and c) naromethane decomposition tomethyl and nitrogen dioxide were searched using the ab !nth° mp2 method. split valence 6-310(d.p) basisset was used for geometry optimizations, frequency and 1rc computations along each reaction...

Spectral clustering has attracted much research interest in recent years since it can yield impressively good clustering results. Traditional spectral clustering algorithms first solve an eigenvalue decomposition problem to get the low-dimensional embedding of the data points, and then apply some heuristic methods such as k-means to get the desired clusters. However, eigenvalue decomposition is...