79,135 research outputs found
Asymptotically Hilbertian Modular Banach Spaces: Examples of Uncountable Categoricity
We give a criterion ensuring that the elementary class of a modular Banach
space E (that is, the class of Banach spaces, some ultrapower of which is
linearly isometric to an ultrapower of E) consists of all direct sums E\oplus_m
H, where H is an arbitrary Hilbert space and \oplus_m denotes the modular
direct sum. Also, we give several families of examples in the class of Nakano
direct sums of finite dimensional normed spaces that satisfy this criterion.
This yields many new examples of uncountably categorical Banach spaces, in the
model theory of Banach space structures.Comment: 20 page
Evaluation of wet tantalum capacitors after exposure to extended periods of ripple current, volume 2
The application of tantalum capacitors in the Viking Lander includes dc voltage and ripple current electrical stress, high temperature during nonoperating times (sterilization), and high vibration and shock loads. The capacitors must survive these severe environments without any degradation if reliable performance is to be achieved. A test program was established to evaluate both wet-slug tantalum and wet-foil capacitors under conditions accurately duplicating actual Viking applications. Test results of the electrical performance characteristics during extended periods of ripple current, the characteristics of the internal silver migration as a function of extended periods of ripple current, and the existence of any memory characteristics are presented
Observations of Backscatter from Sand and Gravel Seafloors Between 170-250 kHz
Interpreting observations of frequency-dependence in backscatter from the seafloor offers many challenges, either because multiple frequencies are used for different observations that will later be merged or simply because seafloor scattering models are not well-understood above 100 kHz. Hindering the understanding of these observations is the paucity of reported, calibratedacoustic measurements above 100 kHz. This manuscript seeks to help elucidate the linkages between seafloor properties and frequency-dependent seafloor backscatter by describing observations of backscatter collected from sand, gravel, and bedrock seafloors at frequencies between 170 and 250 kHz and at a grazing angle of 45°. Overall, the frequency dependence appeared weak for all seafloor types, with a slight increase in seafloor scattering strength with increasing frequency for an area with unimodal, very poorly to moderately well sorted, slightly granular to granular medium sand with significant amounts of shell debris and a slight decrease in all other locations
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