Electrical and Low Frequency Noise Characterization of Graphene Chemical Sensor Devices Having Different Geometries.

Chemiresistive graphene sensors are promising for chemical sensing applications due to their simple device structure, high sensitivity, potential for miniaturization, low-cost, and fast response. In this work, we investigate the effect of (1) ZnO nanoparticle functionalization and (2) engineered defects onto graphene sensing channel on device resistance and low frequency electrical noise. The engineered defects of interest include 2D patterns of squares, stars, and circles and 1D patterns of slots parallel and transverse to the applied electric potential.

Observation of plasmon-phonons in a metamaterial superconductor using inelastic neutron scattering.

A metamaterial approach is capable of drastically increasing the critical temperature, , of composite metal-dielectric superconductors as demonstrated by the tripling of that was observed in bulk Al-AlO coreshell metamaterials. A theoretical model based on the Maxwell-Garnett approximation provides a microscopic explanation of this effect in terms of electron-electron pairing mediated by a hybrid plasmon-phonon excitation. We report an observation of this excitation in Al-AlO core-shell metamaterials using inelastic neutron scattering.

Determining the nature of the gap in semiconducting graphene.

Since its discovery, graphene has held great promise as a two-dimensional (2D) metal with massless carriers and, thus, extremely high-mobility that is due to the character of the band structure that results in the so-called Dirac cone for the ideal, perfectly ordered crystal structure. This promise has led to only limited electronic device applications due to the lack of an energy gap which prevents the formation of conventional device geometries. Thus, several schemes for inducing a semiconductor band gap in graphene have been explored.

Enhanced superconductivity in aluminum-based hyperbolic metamaterials.

One of the most important goals of condensed matter physics is materials by design, i.e. the ability to reliably predict and design materials with a set of desired properties.

Disordered RuO2 exhibits two dimensional, low-mobility transport and a metal-insulator transition.

The discovery of low-dimensional metallic systems such as high-mobility metal oxide field-effect transistors, the cuprate superconductors, and conducting oxide interfaces (e.g., LaAlO3/SrTiO3) has stimulated research into the nature of electronic transport in two-dimensional systems given that the seminal theory for transport in disordered metals predicts that the metallic state cannot exist in two dimensions (2D).

Functionalized graphene as a model system for the two-dimensional metal-insulator transition.

Reports of metallic behavior in two-dimensional (2D) systems such as high mobility metal-oxide field effect transistors, insulating oxide interfaces, graphene, and MoS2 have challenged the well-known prediction of Abrahams, et al. that all 2D systems must be insulating. The existence of a metallic state for such a wide range of 2D systems thus reveals a wide gap in our understanding of 2D transport that has become more important as research in 2D systems expands.

Using metamaterial nanoengineering to triple the superconducting critical temperature of bulk aluminum.

Recent experiments have shown the viability of the metamaterial approach to dielectric response engineering for enhancing the transition temperature, Tc, of a superconductor. In this report, we demonstrate the use of Al2O3-coated aluminium nanoparticles to form the recently proposed epsilon near zero (ENZ) core-shell metamaterial superconductor with a Tc that is three times that of pure aluminium. IR reflectivity measurements confirm the predicted metamaterial modification of the dielectric function thus demonstrating the efficacy of the ENZ metamaterial approach to Tc engineering.

Experimental demonstration of superconducting critical temperature increase in electromagnetic metamaterials.

A recent proposal that the metamaterial approach to dielectric response engineering may increase the critical temperature of a composite superconductor-dielectric metamaterial has been tested in experiments with compressed mixtures of tin and barium titanate nanoparticles of varying composition. An increase of the critical temperature of the order of ΔT ~ 0.15 K compared to bulk tin has been observed for 40% volume fraction of barium titanate nanoparticles.

The role of moral disengagement in the execution process.

The present study tested the proposition that disengagement of moral self-sanctions enables prison personnel to carry out the death penalty. Three subgroups of personnel in penitentiaries located in three Southern states were assessed in terms of eight mechanisms of moral disengagement. The personnel included the execution teams that carry out the executions; the support teams that provide solace and emotional support to the families of the victims and the condemned inmate; and prison guards who have no involvement in the execution process.

The fate of the tumor remnant after less-than-complete acoustic neuroma resection.

Objectives: We sought to determine the recurrence rate after near-total and subtotal resection of acoustic neuroma.

Study Design, Setting, And Patients: We conducted a retrospective chart review of a total of 79 patients: 50 with near-total resections (remnant < or =25 mm(2) and < or =2 mm thick) and 29 with subtotal resections (any larger remnant). Surgical approach included 5 middle fossa, 17 retrosigmoid, and 57 translabyrinthine.

The psychological experience of security officers who work with executions.

Open-ended interviews were conducted with members of the "Execution Team" in Louisiana in order to understand the roles, experiences, and effects of carrying out the death penalty. Fifty of a potential 52 correctional officers who work with executions were interviewed and asked to complete mental health inventories. While emphasizing the importance of security and their professional responsibilities in carrying out the death penalty, the officers stress their respect and decency toward the inmates and all others involved with the process.

New insight into enhanced superconductivity in metals near the metal-insulator transition.

We have studied the transport properties of disordered WSi films near the metal/insulator transition (MIT) and we have also reviewed the data for several other disordered materials near their MIT. In all cases, we found the presence of enhanced superconductivity. We constructed a superconductivity "phase diagram" (i.

Does exogenous GM1 ganglioside enhance the effects of electrical stimulation in ameliorating degeneration after neonatal deafness?

This study examined the combined effects of administration of exogenous GM1 ganglioside and electrical stimulation on the cochlear nucleus (CN) of cats deafened neonatally by ototoxic drugs. Five normal hearing adult cats served as controls. Another 12 cats were deafened bilaterally by daily injections of neomycin sulfate (60 mg/kg) for 17-21 days after birth until auditory brainstem testing demonstrated profound hearing loss.

Measuring the spin polarization of a metal with a superconducting point contact.

A superconducting point contact is used to determine the spin polarization at the Fermi energy of several metals. Because the process of supercurrent conversion at a superconductor-metal interface (Andreev reflection) is limited by the minority spin population near the Fermi surface, the differential conductance of the point contact can reveal the spin polarization of the metal. This technique has been applied to a variety of metals where the spin polarization ranges from 35 to 90 percent: Ni0.

Direct Observation of Microscopic Inhomogeneities with Energy-Dispersive Diffraction of Synchrotron-Produced X-rays.

Evidence of structural inhomogeneities in two high-transition-temperature superconductors, YBa(2)Cu(3)O(7-delta) and Nd2-xCexCuO4-y, is presented. When samples were illuminated by highly collimated x-rays produced on a synchrotron wiggler, small changes in the lattice were detected over a spatial scale of 10 micrometers. These changes are interpreted as evidence of variations in the oxygen content in one case and in the cerium content in the other; both affect the superconducting properties.