Recent advances in Raman spectroscopy for characterizing graphene, graphite, and carbon nanotubes are reviewed comparatively We first discuss the first-order and the double-resonance (DR) second-order Raman scattering mechanisms in graphene, which give rise to the most prominent Raman features Then, we review phonon-softening phenomena in Raman spectra as a function of gate voltage, which is known as the Kohn anomaly Finally, we review exciton-specific phenomena in the resonance Raman spectra of single-wall carbon nanotubes (SWNTs) Raman spectroscopy of SWNTs has been especially useful for understanding many fundamental properties of all sp2 carbons, given SWNTs can be either semiconducting or metallic depending on their geometric structure, which is denoted by two integers (n,m)

Characterizing Graphene, Graphite, and Carbon Nanotubes by Raman Spectroscopy

A photoconductive imaging member comprised of a substrate, a photogenerating layer, and thereover a charge transport layer comprised of a charge transport component or components, a polymer binder and metal oxide particles, wherein said metal oxide particles contain or are attached with or to a silane or a siloxane, or alternatively a polytetrafluoroethylene.

Photoconductive imaging members

Catheter systems and methods for implanting helical or dart-like implants into the myocardium or other body tissue. The catheter system includes a helix for fixing the distal end of the catheter to the myocardium, an implant held by the helix, mechanisms for driving the fixation helix into the myocardium, and mechanisms for driving the implant into the myocardium, removing the fixation helix and leaving the implant behind. The implant may be coated, filled, or made of a drug or drug eluting compound, or drug delivery matrix of any composition.

Implant Delivery Catheter System And Methods For Its Use

Polymeric electro-optic materials have recently been developed that, when fabricated into devices such as Mach-Zehnder interferometers, permit drive ( Vπ) voltages of less than 1 V to be realized at the telecommunications wavelength of 1.3 and 1.55 microns. Operation of polymeric electro-optic modulators to frequencies (bandwidths) of greater than 100 GHz has been demonstrated. The total insertion loss of polymeric electro-optic modulators has been reduced to values as low as 5 dB, which is competitive with values obtained for lithium niobate modulators and is much lower than that obtained for gallium arsenide electro-absorptive modulators. Polymeric electro-optic modulators can be operated for long periods of time at temperatures on the order of 100 °C. Techniques have been developed for seamlessly integrating polymeric electro-optic circuitry with passive low loss optical circuitry (e.g., silica long-haul transmission fiber and medium-range fluoropolymer fibers) and with very large scale integration (VLSI) semiconductor electronics. These advances have created a considerable interest in the commercialization of polymeric electrooptic materials. Polymeric electro-optic materials are now being evaluated for applications such as phased array radar, satellite and fiber telecommunications, cable television (CATV), optical gyroscopes, electronic counter measure (ECM) systems, backplane interconnects for high-speed computers, ultrafast (100 Gbit/s) analog-to-digital (A/D) converters, land mine detection, radio frequency (rf) photonics, and spatial light modulators. This review discusses the structure-function relationships that had to be defined and the synthesis and processing advances achieved before materials appropriate for commercialization could be produced. Topics discussed include the design and synthesis of chromophores that simultaneously exhibit large molecular hyperpolarizability, low optical absorption, processability (e.g., solubility in various processing media), and the prerequisite (thermal, chemical, electrochemical, and photochemical) stability to survive conditions encountered in the fabrication and operation of polymeric electro-optic devices. Chromophore-chromophore intermolecular electrostatic interactions have been shown to be the most serious problem impeding the optimization of electro-optic activity in organic materials. The quantitative theoretical treatment of such interactions by equilibrium and Monte Carlo statistical mechanical methods is discussed. Rules for designing chromophores with shapes leading to maximum obtainable electro-optic activity are discussed and the synthetic realization of such structures is reviewed. The role of electrostatic interactions in influencing the choice of processing conditions is also discussed. A number of processing steps, including spin casting, electric-field poling, lattice hardening, fabrication of buried channel waveguides (including deposition of cladding layers), electrode deposition and connection with electronic circuitry, and integration of active and passive optical circuitry, are required. Each of these steps can affect device performance (e.g., influence optical loss, electro-optic activity, and stability). The systematic optimization of each of these steps is reviewed. Finally, device design and operation are reviewed and speculation on the future of the field is expressed.

Nonlinear Optical Polymeric Materials: From Chromophore Design to Commercial Applications

Apparatus and methods for accessing data on a multilayered optical storage medium. The apparatus uses the time-of-flight of illumination directed to and reflected by the layers of the optical medium to access data stored on a desired layer of the medium. More particularly, alterations in illumination reflected from the desired layer are detected to access data stored on the layer. In accordance with embodiments of the invention utilizing interferometric techniques, the time-of-flight of a reference illumination is adjusted to cause interference of the reference illumination with the illumination reflected from the layer which contains the data to be accessed. Alternatively, and in accordance with embodiments of the invention utilizing non-interferometric techniques, the time-of-flight of illumination reflected by the layer which contains the data to be accessed is selected to permit data stored on the desired layer to be accessed.

Apparatus and method for accessing data on multilayered optical media

Barrier coating mixtures include (a) a non-butyl elastomeric polymer; (b) an acid or base treated dispersed, substantially exfoliated silicate filler material that has not been functionalized with organic cations having an aspect ratio greater than 25; and (c) at least one additive, wherein the total solids content is less than 30% and the amount of filler is between 5% to about 60% of the total solids content. The coating retains its permeability properties under strain and has a strain to first damage of at least 5% biaxial elongation at 0% RH. Coated articles, free standing films and membranes, which are flexible and elastomeric, are produced using the barrier coating mixtures. Methods of 15 manufacturing of such coated products are also encompassed.

Barrier coating of a non-butyl elastomer and a dispersed layered filler in a liquid carrier and coated articles

A polymeric composition which has a dielectric constant K' greater than 4 at 20 °C which varies little with temperature is made from a polymer or mixture of polymers and a ceramic or a mixture of ceramics, where the polymer or mixture of polymers has a dielectric constant K' in the range of about 1.5 to about 3.5 and a temperature coefficient of dielectric constant TCK' that is negative and is between 0 and about -300 ppm/°C; and the ceramic includes a first ceramic, which may be one ceramic or a mixture of ceramics, each having a dielectric constant in the range of about 15 to about 200 and a TCK' that is positive and is between 0 and about 3000 ppm/°C; and an optional second ceramic, which may be one ceramic or a mixture of ceramics, each having a dielectric constant in the range from about 3 up to about 15 and a TCK' that is positive and is between 0 and about 300 ppm/°C.

Polymeric compositions having a temperature-stable dielectric constant

Provided is an optical data storage medium suitable for use with optical recording and playback apparatus and a method of producing the same. The optical data storage medium according to the present invention comprises a textured surfaced information layer comprised of at least one encapsulated dye. The texturing is accomplished without additional treatment steps in the formation of the surface irregularities. Not only does the optical data storage medium of the present invention provide for a high degree of contrast between the medium and recorded information but also allows for the recording of a higher density of information.

Textured organic optical data storage media and methods of preparation

A multilayer barrier structure includes a plurality of relatively thin nanocomposite layers separated by one or more relatively thick intermediate layers selected from synthetic elastomers or non-elastomeric polymers. The composites exhibit remarkably long breakthrough and lag-times and are useful for packaging or protective apparel.

Multilayer nanocomposite barrier structures

High magnetic permeability composites are obtained by incorporating ferrite fibers in the composites. The ferrite fibers consist of a polymer and particulate ferrite fill at a concentration above the percolation threshold for the ferrite fill in the polymer (typically greater than 30 volume percent). The aspect ratio and ferrite concentration of the fibers are selected to minimize demagnetization fields in the fibers. The fibers can be dispersed in low concentration in an unoriented fashion in the composites to impart high magnetic permeability to the composite. In other embodiments, the fibers are oriented in the composites to impart high magnetic permeability to the composite for incident radiation of a particular linear polarization.

Harris A. Goldberg

Papers

Barrier coating of a non-butyl elastomer and a dispersed layered filler in a liquid carrier and coated articles

Polymeric compositions having a temperature-stable dielectric constant

Textured organic optical data storage media and methods of preparation

Multilayer nanocomposite barrier structures

High magnetic permeability composites containing fibers with ferrite fill