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Search Publications by: Renu Sharma (Assoc)

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Displaying 26 - 50 of 50

Creating Nanostructured Superconductors by Local Current Annealing

September 17, 2015
Author(s)
Hongwoo H. Baek, Jeonghoon Ha, Duming Zhang, Bharath NMN Natarajan, Jonathan P. Winterstein, Renu Sharma, Rongwei Hu, Kefeng Wang, Steven Ziemak, Johnpierre Paglione, Young Kuk, Nikolai B. Zhitenev, Joseph A. Stroscio
Superconductivity results from a Bose condensate of Cooper-paired electrons with a macroscopic quantum wavefunction. Dramatic effects can occur when the region of the condensate is shaped and confined to the nanometer scale. Recent progress in

The evolution of carbon nanotube network structure in unidirectional nanocomposites resolved by quantitative electron tomography

June 23, 2015
Author(s)
Bharath NMN Natarajan, Noa Lachman, Thomas F. Lam, Douglas Jacobs, Christian J. Long, Minhua Zhao, Brian L. Wardle, Renu Sharma, James A. Liddle
Carbon nanotube (CNT) reinforced polymers are next-generation, high-performance, multifunctional materials with a wide array of promising applications. The successful introduction of such materials is hampered by the lack of a quantitative understanding of

Direct evidence of active and inactive phases of Fe catalyst nanoparticles for carbon nanotube formation

November 1, 2014
Author(s)
Stefano Mazzuccoo, Ying Wang, Mihaela M. Tanase, Matthieu C. Picher, Kai Li, Zhijian WU, Stephan Irle, Renu Sharma
Iron and carbon interactions play an important role in various industrial processes such as steel manufacturing, liquid fuel the production by Fischer Tropsch process and carbon nanotube synthesis by chemical vapor deposition process. Interestingly, iron

Nucleation of Graphene and Its Conversion to Single Walled Carbon Nanotube

October 20, 2014
Author(s)
Matthieu C. Picher, Pin A. Lin, Gomez-Ballesteros L. Jose, Perla Balbuena, Renu Sharma
Nucleation is a critical stage for controlling the molecular building blocks into desired functional crystalline structures. For example, chirality of a single-walled carbon nanotube is determined at nucleation stage when the growing graphene sheet wraps

Multi-method analysis of multiwall carbon nanotube polymer nanocomposite samples after photodegradation

June 16, 2014
Author(s)
Elijah Petersen, Thomas F. Lam, Justin Gorham, Keana Scott, Chris Long, Renu Sharma, Li Piin Sung, James Alexander Liddle, Tinh Nguyen
Nanomaterials can be used as nanofillers to enhance the properties of polymeric materials. However, the effect of weathering on nanocomposites and the potential for nanomaterial release is not yet well understood. Multiple analytical methods are needed to

Twin Plane Re-entrant Mechanism for Catalytic Nanowire Growth

March 12, 2014
Author(s)
Andrew D. Gamalski, Peter W. Voorhees, Renu Sharma, Caterina Ducati, Stephan Hofmann
We observe a twin plane re-entrant based growth mechanism for Au catalyzed Ge nanowire growth using video-rate lattice-resolved environmental transmission electron microscopy. For a [112] growth direction, we find a convex, V-shaped liquid catalyst

Impact of UV Irradiation on the Surface Chemistry and Structure of Multiwall Carbon Nanotube Epoxy Nanocomposites

December 6, 2013
Author(s)
Elijah Petersen, Thomas F. Lam, Justin Gorham, Keana Scott, Chris Long, Deborah Jacobs, Renu Sharma, James Alexander Liddle, Tinh Nguyen
One of the most promising applications of nanomaterials is as nanofillers to enhance the properties of polymeric materials. However, the effect of nanofillers on polymers subject to typical environmental stresses, such as ultraviolet (UV) radiation, high

Metastable Crystalline AuGe Catalysts Formed During Isothermal Germanium Nanowire Growth

June 19, 2012
Author(s)
Andrew D. Gamalski, Jerry Tersoff, Renu Sharma, Caterina Ducati, Stephan Hofmann
We observe the formation of metastable AuGe phases without quenching, during strictly isothermal nucleation and growth of Ge nanowires, using video-rate lattice-resolved environmental transmission electron microscopy. We explain the unexpected formation of

Direct observation of nucleation and early stages of growth of GaN nanowires

February 15, 2012
Author(s)
Rosa E. Diaz, Renu Sharma, Karalee Jarvis, Qinglei Zhang, Subhash Mahajan
We report for the first time direct observations of the nucleation and early stages of growth of GaN nanowires. The nanowires were formed by exposing Au + Ga droplets to ammonia. The formation process was observed in situ, and controlled in real time using

Direct Observation of Hydrogen Spillover in Ni-Loaded Pr-Doped Ceria

January 17, 2012
Author(s)
Vaneet Sharma, Peter A. Crozier, Renu Sharma, James B. Adams
Hydrogen-spillover in Ni-loaded Pr-doped ceria (PDC) was directly observed using an environmental transmission electron microscope (ETEM). Localized reduction of ceria in a H2 atmosphere was observed and attributed to gas-Ni-ceria interactions at the three

Carbon Nanotube Nucleation Driven by Catalyst Morphology Dynamics

November 14, 2011
Author(s)
Elena Pigos, Evgeni S. Penev, Morgana A. Ribas, Renu Sharma, Boris I. Yakobson, Avetik R. Harutyunyan
In situ observation of carbon nanotube nucleation process accompanied by catalyst particle dynamic morphology reconstruction is considered within a thermodynamic approach, and reveals the driving force for the liftoff—a crucial event in the nanotube growth

In Search of Enhanced Electrolyte Materials: A Case Study of Doubly Doped Ceria

October 28, 2011
Author(s)
Pratik Dholabhai, James B. Adams, Peter A. Crozier, Renu Sharma
Various compositions of gadolinium-praseodymium doubly doped ceria (GPDC) have been studied to appreciate the effect of two co-dopants in enhancing the ionic conductivity. A Kinetic Lattice Monte Carlo (KLMC) model of vacancy diffusion in GPDC has been

First-principles Study of Defect Migration in RE-doped Ceria (RE = Pr, Gd)

February 2, 2011
Author(s)
Pratik Dholabhai, James B. Adams, Peter A. Crozier, Renu Sharma
Oxygen vacancy formation and migration in ceria (CeO2) is central to its performance as an ionic conductor. Ceria doped with suitable aliovalent dopants has enhanced oxygen ion conductivity - higher than that of yttria stabilized zirconia (YSZ), the most

Electron Beam Induced Growth of TiO2 Nanostructures

February 1, 2011
Author(s)
Renu Sharma
We report the evolution of TiO2 nanostructures when Au nanoparticles, supported on single crystal TiO2 substrates, were heated in ~2 Torr of flowing O2 in an environmental transmission electron microscope. Nanostructures with different morphologies were