http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Chemically driven carbon-nanotube-guided thermopower waves
Choi, Wonjoon,Hong, Seunghyun,Abrahamson, Joel T.,Han, Jae-Hee,Song, Changsik,Nair, Nitish,Baik, Seunghyun,Strano, Michael S. Nature Publishing Group 2010 NATURE MATERIALS Vol.9 No.5
Theoretical calculations predict that by coupling an exothermic chemical reaction with a nanotube or nanowire possessing a high axial thermal conductivity, a self-propagating reactive wave can be driven along its length. Herein, such waves are realized using a 7-nm cyclotrimethylene trinitramine annular shell around a multiwalled carbon nanotube and are amplified by more than 10<SUP>4</SUP> times the bulk value, propagating faster than 2 m s<SUP>−1</SUP>, with an effective thermal conductivity of 1.28±0.2 kW m<SUP>−1</SUP> K<SUP>−1</SUP> at 2,860 K. This wave produces a concomitant electrical pulse of disproportionately high specific power, as large as 7 kW kg<SUP>−1</SUP>, which we identify as a thermopower wave. Thermally excited carriers flow in the direction of the propagating reaction with a specific power that scales inversely with system size. The reaction also evolves an anisotropic pressure wave of high total impulse per mass (300 N s kg<SUP>−1</SUP>). Such waves of high power density may find uses as unique energy sources.
Choi, Wonjoon,Hong, Jinkee American Chemical Society 2012 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.51 No.45
<P>Carbon nanotubes (CNTs) have been widely explored as next generation embedded-strain-pressure sensors. However, most investigations of CNT sensors did not consider the response time as a critical factor, although the ultrafast sensing of mechanical deformation is very important for the detection of dynamic loading or impact, such as in reactive armor systems. Owing to the low capacitance that shortens the response time of the electrical resistance changes induced by mechanical deformation, CNTs are expected to detect rapid electromechanical transduction without delay. Herein, we fabricate single-walled carbon nanotube (SWNT) films on diverse substrates, and evaluate their applications as sensors to detect rapid electromechanical transduction on a macroscopic scale. Under repetitive, high-speed mechanical loading, the SWNT films generate consistent electrical signal changes, which are accurately synchronized with their strain and the beginning of the deformation.</P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ie301551a'>ACS Electronic Supporting Info</A></P>