Materials Literature
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The structure of porous silicon is investigated by grazing incidence x-ray scattering. Using GISAXS (grazing incidence small-angle x-ray scattering), a systematic pore correlation is observed for all porous silicon types. The quantitative analysis of the measurement has been performed for the ${p}^{\ensuremath{-}}$-ty…
Abstract The oxidative stability of the carbon fiber‐reinforced composite of polyimide was examined, in real time, using the evolved gas analysis techniques. Off‐gas degradation products suggested the onset temperature for chain scissions to be fairly low at about 190–220°C. Based on the off‐gas products present and t…
The synthetic routes to ladder polymers that consist of benzenetetrayl subunits with oxo and methylsulfonio linkages are described. As the key intermediate, poly(phenylene oxide)s having pendant methylsulfenyl groups are prepared by copper-catalyzed oxidative polymerization of the corresponding phenols with O 2 . The…
Abstract Tetrafluoroethylene–hexafluoropropylene (FEP) copolymer sheets were modified by remote H 2 , N 2 , O 2 , and Ar plasmas, and the effects of the modification on adhesion between FEP sheets and copper metal were investigated. The four plasmas were able to modify the FEP surfaces' hydrophilicity. Defluorination…
Abstract We prepared chitosans with various degrees of deacetylation (DDAs) by mixing completely deacetylated chitosan and acetic anhydride at room temperature without serious degradation and O‐substitution. We obtained a standard curve to measure DDA by plotting the IR absorbance ratio of A 1560 /A 2880 against the k…
Several types of defect structures in ${\mathrm{PbWO}}_{4}$ and ${\mathrm{CaMoO}}_{4}$ are studied within the framework of density functional theory. While ${\mathrm{PbWO}}_{4}$ is currently of greater technological interest, we were able to carry out more extensive calculations for ${\mathrm{CaMoO}}_{4},$ including l…
Abstract The synthesis of aromatic poly(ether imide)s containing spirobifluorene units in the polymer backbone is described. 2,2′‐Bis(3,4‐dicarboxyphenoxy)‐9,9′‐spirobifluorene dianhydride, which was used as a new monomer, was synthesized with 2,2′‐dihydroxy‐9,9′‐spirobifluorene as the starting material. In the spiro‐…
We investigate high-field transport in bundles of single-wall carbon nanotubes (SWNTs) with multiple contacts. The bundles carry currents in excess of $250\ensuremath{\mu}\mathrm{A}$ (a current density of ${10}^{9}\mathrm{A}/{\mathrm{cm}}^{2})$ before saturation and electrical breakdown, indicating that conduction is…
A soluble porphyrin dimer linked with bicyclo[2.2.2]octadiene was converted into insoluble conjugated porphyrin dimer by heating at 200 °C, this provides a new strategy for the process control of conjugated porphyrins.
Nanocrystalline iron-rich intermetallic compounds ${\mathrm{Sm}}_{2}{\mathrm{Fe}}_{17\ensuremath{-}x}{\mathrm{Si}}_{x}$ $(x=0,$ 0.5, 1, 1.5, and 2) were studied by means of x-ray diffraction and M\"ossbauer spectroscopy coupled with Curie temperature and magnetization measurements. The mechanically alloyed and anneale…
Abstract Simultaneous small‐ and wide‐angle X‐ray scattering was used to follow changes in the microstructure of native cellulose (cellulose I) fibers during conversion to sodium cellulose I (Na‐cellulose I) by aqueous sodium hydroxide. Wide‐angle X‐ray scattering was used to monitor the extent of conversion, while sm…
Changes in poly(diphenylamine) chains primarily doped with camphorsulfonic acid (PDPA-CSA) during the secondary doping process were spectroscopically characterized. The UV−vis−NIR spectrum of PDPA-CSA treated with m- cresol showed the NIR (1100 nm) tail of the band due to free-carrier absorption, confirming the increa…
Cis and trans influences are of similar magnitude in octahedral complexes of SnIV and SbV while the trans influence is dominant in square planar PtII (d8) and d6-ML6 cases.
Two mesostructured MCM-41 silicas that differ dramatically in hydrothermal stability have been examined by (29)Si MAS NMR spectroscopy and pair distribution function (PDF) analysis of synchrotron X-ray scattering data. The less stable mesostructure assembled from sodium silicate and the substantially more stable deriv…
Abstract Carboxymethyl chitins and chitosans (CM‐chitins, CM‐chitosans) of different substitution sites were prepared under different reaction conditions, and partially depolymerized carboxymethyl chitins of various molecular weights from 24.8 × 10 4 to 0.26 × 10 4 were obtained by degrading with chemical reagents. De…
Doping induced polymerization of C(60) inside single-walled carbon nanotubes is reported using Raman spectroscopy and resistivity measurements as a probe. The resistivity changes from semiconducting for the undoped system to metallic for the doped system. For full intercalation, we observe a chemical reaction inside t…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTArtificial Spinning and Characterization of Silk Fiber from Bombyx mori Silk Fibroin in Hexafluoroacetone HydrateJuming Yao, Hiromi Masuda, Chenhua Zhao, and Tetsuo AsakuraView Author Information Department of Biotechnology, Tokyo U…
This article reviews a new and general theory of nonuniform fluids that naturally incorporates molecular scale information into the classical van der Waals theory of slowly varying interfaces. The method optimally combines two standard approximations, molecular (mean) field theory to describe interface formation and l…
A novel route to nanocomposites consisting of multi-walled carbon nanotubes (MWNTs) embedded in amorphous SiOx is reported; the material has been characterised by high resolution transmission electron microscopy (HRTEM) and high resolution electron energy loss spectroscopy (HREELS); for the first time, and based on ou…
We show how growth by agglomeration can be described by means of algebraic or differential equations which determine the evolution of probabilities of various local configurations. The minimal fluctuation condition is used to define vitrification. Our methods have been successfully used for the description of glass fo…