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In the situation of high resolutions, high sea states and small grazing angles, the sea clutter amplitude distribution has heavy trailing part, this part has a significant impact on the sea surface target detection. This paper introduces a fusion method of sea clutter amplitude distribution model, based on which new amplitude distribution models of sea clutter can be designed, and thus the trailing part of the sea clutter amplitude distribution can be well fitted. Through the verification by using the sea clutter data of UHF, L, and S-band, it is indicated that the introduced fusion method can give a better fit in the trailing part of the sea clutter amplitude distribution than other conventional modeling methods. Further, for the amplitude distribution without heavy trailing part, this method also has a good fitness.

A carboxyl-terminated butadiene-acrylonitrile copolymer (CTBN)-toughened epoxy adhesive cured with 2-ethyl-4-methyl-imidazole (EMI) is described. In the presence of EMI the reaction of carboxyl end-group of the liquid rubber with epoxy group is very rapid, it is practically completed before the appearance of phase separation or gelation. At low CTBN concentrations thie in situ formed domain are discrete globules, which toughen the resin matrix. Aggregation of the dispersed phase begins at the CTBN concentration 30 parts per hundred parts resin (phr); at much higher CTBN concentrations the rubber phase becomes continuous. The EMI concentration is a critical factor for the toughening of the adhesive. A room-temperature lap shear strength maximum of adhesive joint was found at CTBN concentration in the range of 30 to 40 phr. The epoxy adhesive KH-225, toughened with CTBN, has superior fatigue strength to those modified with a nonfunctional liquid butadiene-acrylonitrile copolymer or a liquid statistical copolymer of butadiene-acrylonitrile-acrylic acid.