| Quasi-Molecular Fluorescence from Graphene Oxide |
08 Sep 2011 |
6 pages |
| Authors:
Charudatta Galande; Aditya D Mohite; Anton V Naumov; Wei Gao; Lijie Ci; Anakha Ajayan; Hui Gao; Anchal Srivastava; R B Weisman; Pulickel M Ajayan; RICE UNIV HOUSTON TX DEPT OF MECHANICAL ENGINEERING AND MATERIALS SCIENCE
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 | Aqueous dispersions of graphene oxide (GO) have been found to emit a structured, strongly pH-dependent visible fluorescence. Based on experimental results and model computations, this is proposed to arise from quasi-molecular fluorophores, similar to polycyclic aromatic compounds, formed by the electronic coupling of carboxylic acid groups with nearby carbon atoms of graphene. Sharp and structured emission and excitation features resembling the spectra of molecular fluorophores are present near 500 nm ... |
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| Direct Synthesis of Lithium-Intercalated Graphene for Electrochemical Energy Storage Application |
Jan 2011 |
6 pages |
| Authors:
Ashavani Kumar; Arava L Reddy; Arnab Mukherjee; Madan Dubey; Xiaobo Zhan; Neelam Singh; Lijie Ci; W E Billups; John Nagurny; Gandhi Mital; RICE UNIV HOUSTON TX DEPT OF MECHANICAL ENGINEERING AND MATERIALS SCIENCE
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| A novel approach for bulk synthesis of lithium-intercalated graphene sheets through the reduction of exfoliated graphene oxide in liquid ammonia and lithium metal is reported. It is demonstrated here that as-synthesized lithiated graphite oxide sheets (Li-RGO) can be directly used as an electrode material in lithium batteries. The electrochemical studies on Li-RGO electrodes show a significant enhancement in the specific capacity of the lithium battery over commercially available graphite electrodes. ... |
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| Synthesis of Nitrogen-Doped Graphene Films for Lithium Battery Application |
Jan 2010 |
7 pages |
| Authors:
Arava L Reddy; Anchal Srivastava; Sanketh R Gowda; Hemtej Gullapalli; Madan Dubey; Pulickel M Ajayan; RICE UNIV HOUSTON TX DEPT OF MECHANICAL ENGINEERING AND MATERIALS SCIENCE
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| We demonstrate a controlled growth of nitrogen-doped graphene layers by liquid precursor based chemical vapor deposition (CVD) technique. Nitrogen-doped graphene was grown directly on Cu current collectors and studied for its reversible Li-ion intercalation properties. Reversible discharge capacity of N-doped graphene is almost double compared to pristine graphene due to the large number of surface defects induced due to N-doping. All the graphene films were characterized by Raman spectroscopy, transmission ... |
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| Computational Aerodynamics Modeling of the Reefed Stages of Ringsail Parachutes |
Apr-2009 |
88 pages |
| Authors:
Jason D Christopher; RICE UNIV HOUSTON TX DEPT OF MECHANICAL ENGINEERING AND MATERIALS SCIENCE
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| The Team for Advanced Flow Simulation and Modeling (T*AFSM) at Rice University has been using the Stabilized Space-Time Fluid-Structure Interaction (SSTFSI) they developed to model parachute aerodynamics. The complexity of ringsail parachutes requires additional techniques for successful modeling of the reefed stages. Methods developed for this purpose include sequential shape determination, which is an iterative method for determining a shape and corresponding flow field, and coupled FSI using a circumferentially ... |
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| State Estimation of International Space Station Centrifuge Rotor With Incomplete Knowledge of Disturbance Inputs |
MAY 2005 |
148 pages |
| Authors:
Michael J. Sullivan; RICE UNIV HOUSTON TX DEPT OF MECHANICAL ENGINEERING AND MATERIALS SCIENCE
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| This thesis develops a state estimation algorithm for the Centrifuge Rotor (CR) system where only relative measurements are available with limited knowledge of both rotor imbalance disturbances and International Space Station (ISS) thruster disturbances. A Kalman filter is applied to a plant model augmented with sinusoidal disturbance states used to model both the effect of the rotor imbalance and the 155 thrusters on the CR relative motion measurement. The sinusoidal ... |
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| Fluorinated Single Wall Nanotube/Polyethylene Composites for Multifunctional Radiation Protection |
2003 |
6 pages |
| Authors:
Merlyn X. Pulikkathara; Meisha L. Shofner; Richard T. Wilkins; Jesus G. Vera; Enrique V. Barrera; RICE UNIV HOUSTON TX DEPT OF MECHANICAL ENGINEERING AND MATERIALS SCIENCE
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| Fluorinated Single Wall Nanotubes (f-SWNTs) have been processed in polyethylene by an incipient wetting technique to achieve a well dispersed nanocomposite for radiation protection. In some cases, samples were further processed using the rapid prototyping method of extrusion freeform fabrication. Composites were exposed to 40 MeV proton radiation with a flux of about 1.7x10(exp 7) protons/sq cm/sec to a total fluence of 3x10(exp 10) protons/sq cm. This exposure is consistent ... |
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| The Solubility of Hydrogen in Ni3Al Polycrystals Doped With B and Zr |
1995 |
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| Authors:
L. Yang; R. B. McLellan; RICE UNIV HOUSTON TX DEPT OF MECHANICAL ENGINEERING AND MATERIALS SCIENCE
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| The Solubility of Hydrogen in Ni3Al |
1994 |
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| Authors:
L. Yang; R. B. McLellan; RICE UNIV HOUSTON TX DEPT OF MECHANICAL ENGINEERING AND MATERIALS SCIENCE
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 | The solubility of h in single crystals and polycrystalline samples of ni(3)al has been measured in equilibrium with h(2) gas at atmospheric pressure. in all cases the solubility exhibits a maximum at approximately 750 k. this behavior has been related to the temperature dependence of the site occupation energy. keywords: experimental, ni-25al-1ta, ni-26al-1b, ni3al, aluminum addition, boron addition, hydrogen solubility, oxidation, polycrystalline, single crystal, stoichiometry, tantalum addition, temperature dependence, x-ray ... |
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| Calculation of Compressible Boundary Layers by a Hybrid Finite Element Method. |
MAY 1993 |
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| Authors:
A. J. Meade; RICE UNIV HOUSTON TX DEPT OF MECHANICAL ENGINEERING AND MATERIALS SCIENCE
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| Preliminary results are presented of a finite element/finite difference method(semidiscrete Galerkin or SDG method) used to calculate compressible turbulent boundary-layer flow about airfoils, in which the group finite element scheme is applied to the Dorodnitsyn formulation of the boundary-layer equations. The finite element discretization across the layer yields a system of first-order ordinary differential equations in the streamwise direction. Linear elements are chosen for computational efficiency, while also providing adequate ... |
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