Effects of Adhesive Characteristic on the Test Results of Damping Material's DMP

In the measurement of damping material's dynamic mechanical performance(DMP) using flexural resonating cantilever beam method,the specimen's adhesive characteristic influences the test precision and accuracy. Taking its effect into account,the improved measurement equations based on the resonance method are presented. The simulated results show that,for the sake of weakening the adhesive's influence on the measured results,the adhesive should be spreaded as thin as possible when specimen is prepared,the adhesive's density and loss factor should be selected as small as possible also,and its Young's modulus should be selected according to the damping material being measured;the same adhesion condition effects differently on the test results of different damping materials,i.e. the error due to the adhesive is more inconspicuous if the damping layer has bigger thickness,modulus,loss factor and a certain density according to the damping material being measured. These conclusions provide theoretical basis for selecting adhesive,improving adhesion technology,and designing specimen.

Solution-phase synthesis of ordered mesoporous carbon as resonant-gravimetric sensing material for room-temperature H2S detection

H2S can cause multiple diseases and poses a great threat to human health.However,the precise detection of extremely toxic H2S at room temperature is still a great challenge.Here,a facile solvent evaporation induced aggregating assembly(EIAA)method has been applied for the production of ordered mesoporous carbon(OMCs)in an acidic THF/H2 O solution with high-molecular-weight poly(ethylene oxide)-b-polystyrene(PEO-b-PS)copolymers as the structure-directing agent,formaldehyde and resorcinol as carbon precursors.Along with the continuous evaporation of THF from the mixed solution,cylindrical micelles are formed in the solution and further assemble into highly ordered mesostructure.The obtained OMCs possesses a two-dimensional(2 D)hexagonal mesostructure with uniform and large pore diameter(~19.2 nm),high surface area(599 m2/g),and large pore volume(0.92 cm3/g).When being used as the resonant cantilever gas sensor for room-temperature H2S detection,the OMCs has delivered not only a superior gas sensing performance with ultrafast re s ponse(14 s)and recovery(21 s)even at low concentration(2 ppm)but also an excellent selectivity toward H2S among various common interfering gases.Moreover,the limit of detection is better than 0.2 ppm,indicating its potential application in environmental monitoring and health protection.