Thermopile detectors are widely used in uncooled applications where small numbers of detectors are required, particularly in low-cost commercial applications or applications requiring accurate radiometry. Arrays of thermopile detectors, however, have not been developed to the extent of uncooled bolometer and pyroelectric/ferroelectric arrays. Efforts at JPL seek to remedy this deficiency by dev...

This paper presents an active resonant conductance method (ARCM) for the design of large traveling-wave-fed SIW linear slot arrays. Two key slot parameters, slot offsets and lengths, are derived from excitation coefficients with intermediary active resonant conductance. In this method, both dominant mode mutual coupling which includes external & internal and higher order modes mutual coupling a...

Hardware implementation of data compression algorithms is receiving increasing attention due to exponentially expanding network traffic and digital data storage usage. In this paper, we propose several serial one-dimensional and parallel two-dimensional systolic-arrays for Lempel–Ziv data compression. A VLSI chip implementing our optimal linear array is fabricated and tested. The proposed array...

fe49co33ni18 nanowire arrays (175 nm in diameter and lengths ranging from 5 to 32μm) were fabricated into nanopores of hard-anodized aluminum oxide templates using pulsed ac electrodeposition technique. hysteresis loop measurements indicated that increasing the length decreases coercivity and squareness values (from 274 oe and 0.58 to200 oe and 0.105, respectively), indicating the increase in m...

Arrays of loudspeakers are often used for sound reinforcement in large concert halls, auditoria, houses of worship and outdoor events. Arrays of microphones have long been used in applications such as sonar and tomography, and are becoming more important for things like teleconferencing. Global optimization techniques such as Stochastic Region Contraction can be combined with previously develop...

This paper describes the characteristics of a software developed on MatLab Scripts to obtain the radiation patterns of linear antenna arrays using dipoles as the elements. The software includes, among several other options: the analysis and design of arrays with progressive phase, arrays with non uniform amplitude excitation and arrays with non uniform separation. Some special attributes of the...

The use of piezoelectric wafer active sensors (PWAS) phased arrays for Lamb wave damage detection in thin-wall structures is presented. The PWAS capability to tune into specific Lamb-wave modes (which is an enabling factor for our approach) is first reviewed. Then, a generic beamforming formulation that does not require the conventional parallel-ray approximation is developed for PWAS phased ar...

a noninteracting quantum-dot arrays side coupled to a quantum wire is studied. transport through the quantum wire is investigated by using a noninteracting anderson tunneling hamiltonian. the conductance at zero temperature develops an oscillating band with resonances and antiresonances due to constructive and destructive interference in the ballistic channel, respectively. moreover, we have fo...

The structure of the “star” defect in 4H-SiC substrates and its effects on the extended defect structures in the epilayers were studied by molten KOH etching and transmission x-ray topography. Star defects consist of a center region with high densities of threading dislocations (both edge and screw types) and six arms of dislocation arrays extending along <11-20> directions. In addition, multip...

A series of meso-meso, β-β, β-β triply linked linear, radial and square-type zinc(II) porphyrin arrays consist of the constituent porphyrin units and naphthalene junctions. To understand the unique nature of triply linked porphyrin arrays, numerous research activities have been focused on the electronic structures of the constituent porphyrin units. In this study, however, we have paid attentio...