Materials Literature
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Observation of room-temperature single-electron tunneling (SET) in a conjugated polymer is reported. It is observed that conjugated polymers in the high doping level are composed of some ordered (metallic) and disordered (semiconducting) regions. This property has been exploited in conducting polypyrrole nanotubes to…
We have fabricated Cr-doped bulk Ge single crystal using the vertical gradient solidification method. The material shows ferromagnetic ordering at 126 K, as determined from temperature-dependent magnetization and resistance measurements. A sample with x=0.01 was p type with nh=3×1017 cm−3 at 350 K. The measured magnet…
Erosion of hydrocarbon films is investigated in a particle-beam experiment employing sources for argon ions and hydrogen atoms. Sputtering by argon ions sets in above a threshold of 58 eV and reaches a yield of 0.5 at an ion energy of 800 eV. Sputtering by argon ions with an additional flux of thermal hydrogen atoms t…
A curious effect is reported whereby an electric field apparently greatly affects the conductivity of an organic polymer, poly-3,4-ethylenedioxythiophene (PEDOT), doped to the “metallic” conducting regime when it is used in an all-organic polymer field effect transistor configuration. The response time for change in c…
We report on the fabrication and operation of integrated gated field emission devices using single vertically aligned carbon nanofiber (VACNF) cathodes where the gate aperture has been formed using a self-aligned technique based on chemical mechanical polishing. We find that this method for producing gated cathode dev…
We have coupled a high efficiency polarimeter based on exchange scattering from a magnetized target to a hemispherical analyzer. The target is a Fe(001)-p(1×1)O surface which gives rise to highly spin-dependent scattering in the 4–6 eV electron kinetic energy range. Due to the low scattering energy, the design of the…
We report on measurements of the thermal conductivity of a number of amorphous materials, including fluorinated silicate glass and carbon-doped oxides. These materials are of interest to the microelectronics industry for use as insulators in microprocessors. The samples measured were in the form of thin films deposite…
Abstract The efficiency of a macromolecular compatibilizer for reactive blending is strongly dependent on its potentiality of producing a grafted or block copolymer during processing. For the preparation of such a compatibilizer, the grafting of two different reactive groups onto the backbones of ethylene/propylene co…
The magnetization reversal processes of in situ ordered FePt thin films prepared by magnetron sputtering have been studied. A kind of nonmagnetic Ru pinning layer inserted in the FePt magnetic layer was described to introduce controllable pinning sites. The magnetization reversal mechanism of FePt thin films was obser…
Monomer styrene and initiator 2,2‘-azobis(isobutyronitrile) (AIBN) dissolved in supercritical (SC) CO 2 were impregnated into SC CO 2 −swollen polypropylene (PP) matrix at 35.0 °C, and the monomer were then polymerized within the PP substrates at 70 °C, resulting in polypropylene/polystyrene (PP/PS) composites. The Yo…
An explicit example of one-dimensional shearing is used to illustrate the necessity of extra boundary conditions for a class of incremental theories of plasticity regarded as otherwise conventional apart from a dependence of the tangential moduli on gradients of plastic strain.
Electron-density distributions of paraelectric and ferroelectric ${\mathrm{SrBi}}_{2}{\mathrm{Nb}}_{2}{\mathrm{O}}_{9}$ were analyzed by means of synchrotron x-ray diffraction. The obtained electron-density distributions well reproduced the atomic arrangements of the material. Bonding electrons due to hybridization of…
In previous studies in rats and goats, hydrophilic compositions of the PEOT/PBT block copolymer family have shown in vivo calcification and bone bonding. These copolymers are therefore interesting candidates as scaffolding materials in bone tissue engineering applications. Model studies using goat bone marrow stromal…
Freshly precipitated alumina gel consists of very small particles (amorphous to XRD) that are agglomerated into larger particles (∼12 μm). When those particles are abruptly transferred into a solution at a pH equal or greater than 7 and at a temperature greater than 65 °C, an aging process occurs. The experiments perf…
Dielectric susceptibility measurements in a wide frequency spectrum were used to obtain the distribution of relaxation times. This was performed by solving the integral equation for the susceptibility with the Tikhonov regularization technique. This method allows to extract the distribution of the relaxation times and…
The call for brighter synchrotron X-radiation sources for use in structural biology research is barely audible as we enter the new millennium. Our brightest sources are already creating havoc when used at design specifications because of radiation damage. The time is long overdue to take stock of where we are and wher…
The possibility of using smectic liquid crystals in active wave- guide devices is explored through the analysis of both an integrated electro-optic switch and a continuously tunable filter. The two devices are based on a Bragg grating in planar waveguide with a liquid crystal over- layer, which enables changing the sp…
The formulation of Fermat's principle for electromagnetic waves traveling in materials with a negative refractive index is refined. It is shown that a formulation in terms of the minimum (or extremum) of wave travel time between two points is not correct in general. The correct formulation involves the extremum of the…
BaPbO 3 (BPO)/PbZr0.53Ti0.47 (PZT)/BPO heterostructures were fabricated by combining the sol-gel and rf-magnetron sputtering techniques. Experimental results indicate that the BPO bottom electrodes effectively prevent the formation of the rosette structure of PZT, producing smooth surfaces. Additionally, ferroelectric…
Surface potential and the amount of charging on an insulator surface under electron beam irradiation have been quantitatively measured. For these measurements, a special sample holder was developed. The surface potential was measured using a secondary electron method. The measurement of the surface potential revealed…