Phase and delay in corporate-fed arrays
The distribution of phase and delay in corporate-fed phased arrays is examined. RMS phase errors versus scan angle are shown for digital phasers. The phaser bits should all be located at each element. The delayer bits can be also, but delayer loss, dispersion, temperature sensitivity, and size mitigate against using so many delayers. Alternative topologies, where delay bits are distributed in the corporate feed, are examined.
Time delay unit quantization at the subarray level for large, wideband linear arrays
Time delay units become larger and more expensive as the number of bits and physical size of the bits increases. The goal is to reduce the number of large bits in the array by placing them back in the feed network where they are shared my many elements. As the bits are moved back in the feed network, time delay quantization increases and produces errors in the array factor. This paper presents trade-offs between reducing the number of time delay bits and maintaining a desirable array pattern.
Molecular diversity of skin mucus lectins in fish.
Among lectins in the skin mucus of fish, primary structures of four different types of lectin have been determined. Congerin from the conger eel Conger myriaster and AJL-1 from the Japanese eel Anguilla japonica were identified as galectin, characterized by its specific binding to beta-galactoside. Eel has additionally a unique lectin, AJL-2, which has a highly conserved sequence of C-type lectins but displays Ca(2+)-independent activity. This is rational because the lectin exerts its function on the cutaneous surface, which is exposed to a Ca(2+) scarce environment when the eel is in fresh water. The third type lectin is pufflectin, a mannose specific lectin in the skin mucus of pufferfish Takifugu rubripes. This lectin showed no sequence similarity with any known animal lectins but, surprisingly, shares sequence homology with mannose-binding lectins of monocotyledonous plants. The fourth lectin was found in the ponyfish Leiognathus nuchalis and exhibits homology with rhamnose-binding lectins known in eggs of some fish species. These lectins, except ponyfish lectin, showed agglutination of certain bacteria. In addition, pufflectin was found to bind to a parasitic trematode, Heterobothrium okamotoi. Taken together, these results demonstrate that skin mucus lectins in fish have wide molecular diversity.