Abstract: We demonstrate a carbon nanotube based high-resolution biosensor for acetylcholine sensing. Carbon nanotubes are deposited on a silicon wafer in a repeated fashion with layer-by-layer nano self-assembly technique. With nano-assembled acetylcholinesterase molecules on the surface, the carbon nanotube biosensor is capable of detecting acetylcholine at an ultra-low concentration of 100 pM. The sensitivity of the acetylcholine sensor is measured as 7.2 µA/decade. The real-time measurement shows the response time of the biosensor is approximately 6 sec. Both the carbon nanotube film and the acetylcholinesterase film are crucial in the sensing process. Due to its high resolution, fast response, small size, and low cost, the carbon nanotube biosensor has tremendous potential for applications in medical research and clinical diagnosis.
Abstract: Amorphous and crystalline (rhombohedral structure with  growth direction) boron nanobelts were synthesized by the vapor-liquid-solid technique. Their structure and chemical compositions were studied by various electron and atomic force microscopy techniques. Most amorphous and crystalline belts have a width to thickness ratio of 2 and are covered with a layer of amorphous silicon oxide. The crystalline belt cores are defect-free single crystals. Gold catalyst thickness and synthesis temperature are the two prominent parameters determining structure of the synthesized nanobelts. The elastic modulus and hardness were measured using nanoindentation and atomic force microscopy three-point bending techniques. The indentation elastic modulus and hardness were measured to be 92.84.5 GPa and 8.40.6 GPa for amorphous belts, and 72.73.9 GPa and 6.80.6 GPa for crystalline ones, respectively. The three-point bending elastic moduli were found to be 87.83.5 GPa and 72.22.4 GPa for amorphous and crystalline, respectively. The measured mechanical properties are 4-5 times lower than those of the counterpart bulk materials.
Abstract: Chemical reduction of ferric acetylacetonate (Fe(acac)3) and platinum acetylacetonate (Pt(acac)2) using polyol as a reducing agent as well as an effective surfactant, has successfully yielded monodisperse FePt nanoparticles with a size of approximately 2 nm. When annealed samples were compared to FePt nanoparticles synthesized using oleic acid and oleylamine as the surfactants under identical conditions, nearly 30% increase in coercivity (Hc) was achieved with the new, simple and economic method.
Abstract: We present a microscopic description for the impacting process of silicon nanospheres onto a silicon substrate. In spite of the relatively low energy regime considered (up to 1 eV/atom), the impacting process exhibits a rich behavior: A rigid Hertzian model is valid for speeds below 500 m/s, while a quasi-ellipsoidal deformation regime emerges at larger speeds. Furthermore, for speeds up to 1000 m/s the particle undergoes a soft landing and creates a long-lived coherent surface phonon. Higher speeds lead to a rapid attenuation of the coherent phonon due to a partial diamond cubic to-tin phase transformation occurring in the particle.
Abstract: The magnetorheological (MR) effect of multi-walled carbon nanotubes (MWNT) was investigated. Three concentrations of MWNT were dispersed in mineral oil (0.5, 1.5 and 2.53 vol% nanotubes). Rheological investigations were conducted on a magnetorheological cell coupled to a controlled stress rheometer. Oscillatory tests and rotational tests were conducted. A sinuisoidal strain between 0 and 1 with a frequency of 1 Hz was applied and the stress amplitude measured for 0, 171 and 343 kA/m magnetic field strengths. Linear viscoelasticity was determined to exist at strains less than 5%. Dynamic frequency sweeps were conducted at a strain of 1% between 0 and 100 radians/s. A crossover from viscous to elastic behavior was observed for some concentrations. The crossover frequency decreased with field strength as well as with concentration of MWNT. Rotational tests were conducted between shear rates of 0 to 100/s. All dispersions had a zero shear yield stress indicative of Bingham behavior. A magnetosweep was conducted by keeping the strain within the linear viscoelastic region at a frequency of 1 Hz and ramping the magnetic field strength from 0 to 343 kA/m. The results indicate that MWNT show MR behavior.
Abstract: Biomedical Nanotechnology is an emerging area of great scientific and technological opportunity. It is widely recognized as one of the most potentially beneficial applications of nanotechnology to industry and society to date. Work in this area has a number of computational aspects: information technology based tools and measurement techniques are used to study biosystems with micro- and nano-scale physics and chemistry, and computational methods are helping to generate remarkable new insights into how biological systems function, how metabolic processes interrelate, and how new molecular scale machines can operate. This paper reviews current advances in computational algorithms and tools applied to biomedical nanometrics and nano-materials. We categorize algorithms into three general areas, describe representative methods, and conclude with several promising directions of future investigation.
Abstract: We report the fabrication of the orientation preferred structures in BaTiO3 thin films on Ni substrates using pulsed laser deposition. Transmission electron microscopy studies showed that the films consist of crystalline structures of tetragonal BaTiO3. More than 60% of BaTiO3 grains in the films exhibit nearly the same crystallographic orientation with their a-axis lying in the film plane and the  direction parallel to the growth direction. Such orientation preferred structures were grown on a Ni nanocrystalline buffer layer. This result demonstrated the possibility of approximating an oriented single crystalline ceramic oxide structures on metallic substrates.