RESUMO
We present a silicon optomechanical nanobeam design with a dynamically tunable acoustic mode at 10.2 GHz. The resonance frequency can be shifted by 90 kHz/V2 with an on-chip capacitor that was optimized to exert forces up to 1 µN at 10 V operation voltage. Optical resonance frequencies around 190 THz with Q-factors up to 2.2 × 106 place the structure in the well-resolved sideband regime with vacuum optomechanical coupling rates up to g0/2π = 353 kHz. Tuning can be used, for instance, to overcome variation in the device-to-device acoustic resonance frequency due to fabrication errors, paving the way for optomechanical circuits consisting of arrays of optomechanical cavities.
RESUMO
Chemical study of the ethyl acetate extract of the plant endophytic fungus Cladosporium sp. (strain no. IFB3lp-2) yielded three new polyketides (1-3), together with nine known compounds. All of the structures were elucidated on the basis of spectroscopic methods. The isolated compounds were screened for their cytotoxic, antiviral, and acetyl cholinesterase inhibitory activities. Regretfully, no compounds showed any significant activity in these assays.
