Novel β-Benzyloxy-Substituted Copolymers of Seven-Membered Cyclic Carbonate: Ring-Opening Polymerization with L-Lactide, ε-Caprolactone and Trimethylenecarbonate.

To prepare novel biodegradable copolymers with functional substituents that are distributed statistically or randomly over the macromolecule chain and have improved characteristics compared to homopolymers, we conducted a series of synthetic experiments with a novel cyclic monomer, 5-(benzyloxy)-1,3-dioxepan-2-one (). This compound was synthesized, and its homopolymer, as well as its copolymers with L-lactide, ε-caprolactone and trimethylene carbonate, were prepared in a polymerization solution with stannous octoate as the initiator. The formation of the copolymers was confirmed using NMR spectroscopy and DSC data.

[Precedence effect at horizontal and vertical plane and moving lagging signal].

The precedence effect refers to the fact that humans are able to localize sound sources in reverberant environments. In this study, sound localization was studied with dual sound source: stationary (lead) and moving (lag) for two planes: horizontal and vertical. Duration of lead and lag signals was 1s.

[Buildup of echo suppression for the high frequency signal].

The buildup of echo suppression for noise bursts in the band of 5-18 kHz was studied. Durations of the bursts were 5, 10, 20 and 100 ms. Test stimulus were preceded by a train of stimuli.

[Echo thresholds of the precedence effect in the vertical plane].

Echo thresholds were measured for two configurations of loudspeakers in the vertical plane. The first configuration was characterized by the lead sound presentation from a loudspeaker placed in front of a subject, whereas the lag sound was presented from the loudspeaker above the subject's head. In the second configuration, the lead and lag sounds were presented from the same loudspeakers but in reverse order.