Materials Literature
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The synthesis of meso-linked quinone-porphyrin-porphyrin-quinone tetrads has been accomplished by the simple treatment of a CH2Cl2 solution of zincated 5-substituted-10,20-diphenylporphyrins (where the substituent = 3-cyclobutenyl-1,2-dione, various quinonyl derivatives, and p-anisyl) with 2,3-dichloro-5,6-dicyanoquin…
A detailed study of the unique optical properties of free-standing oxidized porous silicon films has been performed. Under continuous-wave laser irradiation, a strongly superlinear light emission and a very large laser-induced absorption are observed. The nonlinear emission is characterized by a sharp intensity increa…
Systematic measurements of the resistivity $\ensuremath{\rho}(T)$ and thermoelectric power $\ensuremath{\alpha}(T)$ under hydrostatic pressure have been made on single-valent perovskites of the family ${\mathrm{LnNiO}}_{3}$ $({\mathrm{L}\mathrm{n}=\mathrm{L}\mathrm{a},\mathrm{}\mathrm{P}\mathrm{r},\mathrm{}\mathrm{N}\…
From second-order Raman scattering we find that the maximum in the phonon density of states of single-walled nanotubes softens by 30 ${\mathrm{cm}}^{\ensuremath{-}1}$ over the value of graphite. A comparison of the phonon-dispersion curves of nanotubes in the literature shows that the ab initio approach best describes…
We study the development of the structure of crystals of colloidal hard spheres in time when gravity effects are minimal and polydispersity is small (<3%). The initial stacking of the close-packed hexagonal layers that make up the crystals is varied by applying various types of shear stress during nucleation of…
Having found much ambiguity in the infrared band assignments for polyamide 66 (PA66), we revisited some of these assignments before using infrared spectroscopy to assess microstructure changes resulting from multiple thermal treatments. We discovered that earlier assignments of the 1144 and 1180 cm−1 bands to the amor…
The special features of diffraction from particles in the nanometer size range are discussed and the problem of structure determination is considered. A direct method of structure analysis, known as Debye Function Analysis, is presented and evaluated. The method is capable of obtaining information about both the size…
When reduced ${\mathrm{TiO}}_{2}(110)$ single crystals are oxidized at moderate temperatures (470--660 K), the surfaces restructure. Interstitial Ti atoms from the bulk diffuse to the surface where they react with gaseous oxygen and form new, added ${\mathrm{TiO}}_{2}$ layers. These are characterized by three structur…
SiO 2 and phosphosilicate glass (PSG) films containing Si nanocrystals (nc-Si) as small as a few nanometers were studied by electron spin resonance (ESR) and photoluminescence (PL), and the correlation between the two measurements was examined. It is shown that the incorporation of nc-Si in SiO2 results in the drastic…
Longitudinal and transverse giant magnetoimpedance (GMI) effects are studied in FeCuNbSiB and FeCuNbSiB/Cu/FeCuNbSiB films. In regard to as-deposited single layer films, hardly any GMI effect can be detected, while for as-deposited sandwiched films, the maximum GMI ratios of 32% and 11% are obtained in longitudinal an…
A series of mono- and dinuclear lanthanum complexes of 15,31-dimethyl-3,11,19,27,33,35-hexaazapentacyclo[27.3.1.1.(5,9)1,(13,17). 1(21,25)]hexatriaconta-5,7,9(33),13,15,17(34),21,23,25(35),29,31, 1(36)-dodecaene-34,36-diol (24RBPyBC, L) have been defined in solution. Their ability to hydrolyze bis(4-nitrophenyl) phosp…
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 ${\…