CARBON NANOMATERIALS FOR CHEMICAL AND BIOLOGICAL SENSING

Carbon nanotubes (CNTs), first discovered in 1991, are cylindrical structures composed of atomically thin sp2 hybridized carbon which can be visualized as a rolled up sheet of graphene. CNTs have excellent mechanical and electronic properties which make them a very promising new material. Typically, CNTs have diameter between one and several nanometers, comparable to the size of individual molecules, and lengths that can exceed several micrometers, which enables integration into microscale electronics. Most interestingly, CNTs electronic properties are very sensitive to changes in their local chemical environment, as all carbon atoms are located on the surface. By placing CNTs between two electrodes, they can function as a resistor or transistor for sensor applications, and through addition functionalization, the CNTs can serve as ultrasensitive, selective devices. Herein, we report the specific functionalization of single-walled carbon nanotubes (SWNTs) for chemical and biological sensing. First, SWNTs have been decorated with metal oxide nanoparticles and a hydrophilic polymer for the detection of CO2 gas. The interactions of the SWNTs with the functional layers have been characterized in detail. Secondly, oxidized SWNTs functionalized with a pH sensitive polymer have been developed for selective detection of the pH of buffered solutions, with the ability to distinguish between 0.1 pH units. This device was also further functionalized to demonstrate detection of CO2 and H2 gas

Quantum Vacuum Contribution to the Momentum of the Dielectric Media

Momentum transfer between matter and electromagnetic field is analyzed. The related equations of motion and conservation laws are derived using relativistic formalism. Their correspondence to various, at first sight self-contradicting, experimental data (the so called Abraham-Minkowski controversy) is demonstrated. A new, Casimir like, quantum phenomenon is predicted: contribution of vacuum fluctuations to the motion of dielectric liquids in crossed electric and magnetic fields. Velocities about $50nm/s$ can be expected due to the contribution of high frequency vacuum modes

Topological order in Josephson junction ladders with Mobius boundary conditions

We propose a CFT description for a closed one-dimensional fully frustrated ladder of quantum Josephson junctions with Mobius boundary conditions, in particular we show how such a system can develop topological order. Such a property is crucial for its implementation as a "protected" solid state qubit.Comment: 14 pages, 3 figures, to appear in JSTA

Analysis of Inter-Limb Asymmetry of Landing Forces and Ankle Injury in Warfighters: A Prospective Study

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Tunneling of a Quantized Vortex: Roles of Pinning and Dissipation

We have performed a theoretical study of the effects of pinning potential and dissipation on vortex tunneling in superconductors. Analytical results are obtained in various limits relevant to experiment. In general we have found that pinning and dissipation tend to suppress the effect of the vortex velocity dependent part of the Magnus force on vortex tunneling.Comment: Latex, 12 page