Materials Literature
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The synthesis of a novel water-soluble polymer drug carrier system based on biodegradable poly(ethylene glycol) block copolymer is described in this paper. The copolymer consisting of PEG blocks of molecular weight 2000 linked by means of an oligopeptide with amino end groups was prepared by interfacial polycondensati…
The dynamic mechanical and thermal properties of natural rubber/poly (methyl methacrylate) blends (NR/PMMA) with and without the addition of graft copolymer (NR-g-PMMA) have been investigated. Dynamic mechanical spectroscopy is used to examine the effect of compatibilizer loading on storage modulus (E′), loss modulus…
Four-probe resistance vs temperature and gate voltage are reported for an individual single-wall carbon nanotube rope before and after doping in situ with potassium. All the features in $R(T)$ from unoriented bulk material, before and after doping, are qualitatively reproduced by the rope data. The 5.3 K conductance o…
The surface molecular orientation of a liquid crystalline (LC) layer made up of semifluorinated (SF) single side groups [−CO−(CH 2 ) x - 1 −(CF 2 ) y F] (single SF groups) attached to polyisoprene homopolymer or the isoprene block of a styrene−isoprene diblock copolymer was determined by analyzing the partial electron…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSurface Characterization and Modification of Indium Tin Oxide in Ultrahigh VacuumKathleen L. Purvis, Gang Lu, Jeffrey Schwartz, and Steven L. BernasekView Author Information Department of Chemistry, Princeton University Princeton, New Jersey 08544-1009 Cite this: J. Am…
We report a diffuse interface or phase field model for simulating electromigration and stress-induced void evolution in interconnect lines. Our approach is based on the introduction of an order parameter field to characterize the damaged state of the interconnect. The order parameter takes on distinct uniform values w…
An analysis of the Stokes and anti-Stokes resonant Raman spectra of single-walled carbon nanotubes (SWNT's) using different laser energies in the range $1.49<~{E}_{\mathrm{laser}}<~2.19$ eV shows major differences in the tangential band spectra for the Stokes and anti-Stokes processes for selected ${E}_{\mathrm{…
We have found quite a new type of transport phenomenon in an organic crystal α-(BEDT-TTF) 2 I 3 under high pressure. Essentially, it is a semimetal or a narrow gap semiconductor. But, the transport property is peculiar. The conductivity of this the carrier (hole) density and mobility change by a about 6 orders of magn…
We report how the structural arrangement of germanium nanowires optimizes surface stability and enables the formation of very thin free-standing crystalline wires. Ge nanowires consisting of a crystalline Ge core and an amorphous ${\mathrm{GeO}}_{2}$ sheath have been formed by laser ablation of a mixture of Ge and ${\…
Using empirical potential molecular dynamics we compute dynamical matrix eigenvalues and eigenvectors for a 4096 atom model of amorphous silicon and a set of models with voids of different sizes based on it. This information is then employed to study the localization properties of the low-energy vibrational states, ca…
We have investigated the crystal structure and the ferroelectric properties of BaTiO3 thin films with YBa2Cu3O7-d as the bottom and Au as the top electrode. Epitaxial heterostructures of YBa2Cu3O7-d and BaTiO3 were prepared by dc and rf sputtering, respectively. The crystal structure of the films was characterised by…
Using the photoluminescence Auger saturation phenomenon, we deduce the values of the absorption cross section of silicon nanocrystals in a wide range of energies. The very large variation of their values versus energy of the absorbed light is attributed to the enhanced optical transition oscillator strength but reduce…
A new technique, dissipative particle dynamics (DPD), appears promising as a means of studying the dynamical behaviour of polymers. Real polymers are known to obey a number of scaling laws, and a simulation method should reproduce these if it is to be relied on. The present work is a study of the properties of polymer…
In this article we report on the temperature dependencies of the longitudinal and shear sound velocities in Ti4AlN3, Ti3Al1.1C1.8, and Ti3SiC2. The velocities are measured using a phase sensitive pulse-echo ultrasonic technique in the 90–300 K temperature range. At room temperature, Young’s, ERT, and shear, μRT, modul…
High-speed optical communication requires ultrafast all-optical processing and switching capabilities. The Kerr nonlinearity, an ultrafast optical nonlinearity, is often used as the basic switching mechanism. A practical, small device that can be switched with ~1-pJ energies requires a large Kerr effect with minimal l…
Single molecule confocal microscopy is used to study fluorescence intermittency of individual ZnS overcoated CdSe quantum dots (QDs) excited at 488 nm. The confocal apparatus permits the distribution of “on” and “off” times (i.e., periods of sustained fluorescence emission and darkness) to be measured over an unpreced…
Scanning tunneling microscopy, spectroscopy, and tight-binding calculations have been used to elucidate the unique structural and electronic properties of single-walled carbon nanotubes (SWNTs). First, the unique relationship between SWNT atomic structure and electronic properties, and the richness of structures obser…
The cooperative Jahn-Teller coupling between the Mn e(g) electrons and the oxygen octahedral distortions in LaMnO3 is studied using ab initio density-functional calculations and tight-binding models. The linear and quadratic vibronic coupling parameters are calculated using density-functional methods. It is shown that…
We have developed the ability to grow reproducible La0.67Sr0.33MnO3/SrTiO3/Al tunnel junctions with high quality gap characteristics for spin-polarization measurements. A YBa2Cu3O7 counterelectrode was required to prevent current crowding. In order to fit our data, we have numerically solved Maki’s equations which inc…
The loss from polypropylene (PP) of sterically hindered amines with molecular weight ranging from 1364 to 2758 in heptane, chloroform, and methanol at room temperature was studied. The additives leak from polymer in heptane and in chloroform and some residual concentration remains in the polymer; the stabilizers show…