Question: A nanobridge is formed of a rigid platform having the dimensions of 200 nm # 200 nm # 2 nm and two identical nanowires of diameter 120 nm and length 30 nm made of a material with E = 140 GPa, G = 100 GPa, and t = 5400 kg/m3 (assume both the plate and nanowires are made of the same material). Decide which of the following two resonance shift methods is more sensitive in detecting a mass quantity of 2 # 10-14 kg:

(a) Bending mode with mass deposited at the center of the plate; the damping coefficient in translation is ct = 4 # 10-9 N-s/m;

(b) Torsional mode with mass deposited off the plate center at a distance of 100 nm; the damping coefficient in rotation is cr = 5 # 10-6 N-m-s. Draw the transmissibility curve for each case assuming sinusoidal input displacement of the base is applied in bending and sinusoidal input rotation of the base is applied in torsion.