Diverse electromagnetic (EM) responses of a programmable metasurface with a relatively large scale have been investigated, where multiple functionalities are obtained on the same surface. The unit cell in the metasurface is integrated with one PIN diode, and thus a binary coded phase is realized for a single polarization. Exploiting this anisotropic characteristic, reconfigurable polarization c...

The localization of fast radio bursts (FRBs) has been hindered by the poor angular resolution of the detection observations and inconclusive identification of transient or variable counterparts. Recently a γ-ray pulse of 380 s duration has been associated with the fast radio burst FRB 131104. We report on radio-continuum imaging observations of the original localization region of the FRB, begin...

O-Demethylabierixin, a new polyether antibiotic, was isolated from a Streptomyces spp. Its structure elucidation was carried out with fast atom bombardment mass spectrometry (FAB-MS) and fast atom bombardment mass spectrometry-mass spectrometry (FAB-MS/MS) by comparing spectral patterns with those of structurally similar polyether compounds, nigericin and abierixin. The collision-induced dissoc...

New techniques are developed for determining spatial or geometric distortion between two images of the same scene. First, the properties of the Fourier transform of a two dimensional function under the affine transformation are given. The relations between the spatial and spectral frequency domains are shown. As a result, techniques for the estimation of the coefficients of the distortion model...

PURPOSE: Non-Cartesian imaging is essential in applications such as ultra-short time-echo imaging and realtime cardiac imaging. However, reconstruction speed becomes a limitation when iterative reconstruction is desired for parallel imaging, compressed sensing or artifact correction. In this work, we propose using pruned Fast Fourier Transform (pruned FFT) to accelerate almost all fast non-Cart...

The time-to-frequency-domain conversion is often required in many applications of the finite-difference time-domain (FDTD) method. This paper presents a new FDTD time-to-frequencydomain conversion algorithm based on the optimization of nonuniform fast Fourier transform (NUFFT) with several redundancy-reduction techniques. The proposed algorithm can perform the FDTD conversion at multiple desire...

The neutron energy spectrum from the atomic bomb consisted of a range of energies from thermal to fast neutrons. Fast neutrons contribute a larger dose to the human body than lowenergy neutrons per unit flux. The evaluation of the fast neutron component has been performed based on analyses of P (>3 MeV) activity measured immediately after the Hiroshima bomb and Ni (>2 MeV), which has a much lon...

In this study, a compact finite-difference discretization is first developed for Helmholtz equations on rectangular domains. Special treatments, then, are introduced for Neumann and Neumann-Dirichlet boundary conditions to achieve accuracy and separability. Finally, a Fast Fourier Transform (FFT) based technique is used to yield a fast direct solver. Analytical and experimental results show thi...

The Fast Fourier Transform (FFT) technique has long been used for spectral analysis but it has not been fully exploited for data compression purposes. This paper presents the concept for compressing telemetry data using the FFT in such a manner that the time domain waveform can be recovered. The sampled time-domain data is transformed into the frequency-domain data and only the significant comp...

Surface composition information from Vesta is reported using fast neutron data collected by the gamma ray and neutron detector on the Dawn spacecraft. After correcting for variations due to hydrogen, fast neutrons show a compositional dynamic range and spatial variability that is consistent with variations in average atomic mass from howardite, eucrite, and diogenite (HED) meteorites. These dat...