Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorBonding at Symmetric Polymer/Polymer Interfaces below the Glass Transition TemperatureYuri M. Boiko and Robert E. Prud'hommeView Author Information Centre de recherche en sciences et ingénierie des macromolécules, Chemistry Department,…
Abstract The synthesis of new functionalised macromers containing perfluoropolyether structures (PFPE) is reported. They are obtained by reaction of bis‐CH 2 OH terminated PFPE with isocyanato‐ethyl methacrylate (EIM), giving rise to the formation of perfluoropolyether bisurethane methacrylate (PFEUMA) oligomers. The…
The anatomy of the tymbal of Cyclochila australasiae was re-described and the mass of the tymbal plate, ribs and resilin pad was measured. The four ribs of the tymbal buckle inwards in sequence from posterior to anterior. Sound pulses were produced by pulling the tymbal apodeme to cause the tymbal to buckle inwards. A…
The adsorption of NO onto copper-exchanged ZSM-5 zeolite has been studied by EPR spectroscopy. A distinct Cu + −NO species possessing an end-on η 1 bent structure has been identified. Its EPR spectrum with a well-defined superhyperfine coupling with 63,65 Cu nuclei and hyperfine coupling with 14 N was interpreted in t…
Abstract Iron-manganese concretions are common in upper sola of Alfisols in the Inner Bluegrass Region of Kentucky. Their nature and quantities appear to be related to the fluctuation of seasonal perched water tables above clayey argillic horizons. This study was conducted to examine changes in the macro-and micromorp…
Indexed X-ray powder diffraction data are reported for the low temperature tetragonal ZrO 2 obtained by crystallization of zirconia gel. The structure was refined by the Rietveld technique on the basis of space group P 4 2 / nmc . Refined unit cell dimensions are a = 3.5984(5) Å, c = 5.152(1) Å, V = 66.71 Å 3 , D x =6…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTMicrostructural Analysis of a Cubic Bicontinuous Morphology in a Neat SIS Triblock CopolymerJonathan H. Laurer, Damian A. Hajduk, Jennifer C. Fung, John W. Sedat, Steven D. Smith, Sol M. Gruner, David A. Agard, and Richard J. SpontakView Author Information Department of Materia…
The heat capacity of ${\mathrm{LaCoO}}_{3}$ has been determined from 13 to 1000 K by adiabatic calorimetry. A spin transition, reported to occur between 20 and 100 K, is reflected in the heat capacity as a small, broad hump. A more substantial heat-capacity contribution, of electronic origin also, has its maximum at \…
This paper presents computer simulation studies of boron nitride using ab initio and empirical methods. Results of self-consistent DFT-LDA calculations are shown, which were performed to characterize static ground-state properties of the different BN modifications. With help of these calculations the cubic phase is pr…
Examples of experimental contact angle data for varying drop and bubble volumes on different solids whose surfaces are smooth and homogeneous, rough and homogeneous, smooth and heterogeneous, and covered with unstable organic films are presented. The ideas and theoretical models as proposed in the literature for the i…
Thiol-containing polyphenolics are enzymatically synthesized in the microstructured environment of reversed micelles. CdS semiconductor nanocrystallites, also synthesized in the water pools of reversed micelles, are then attached to these polymers through binding to the sulfhydryl groups. The polymer−CdS nanocomposite…
A Bi 2 O 3 compound which is unknown to date has been synthesized at 800 °C on a BeO substrate. α- Bi 2 O 3 at 800 °C undergoes a phase transition to a metastable new compound named ω- Bi 2 O 3 which in turn transforms to stable δ- Bi 2 O 3 at 900 °C. X-ray powder diffraction data were collected, indexed, and refined…
Nylons 8 10 and 10 12 have been synthesized and crystallized as chain-folded lamellae from 1,4-butanediol and the results compared with previous studies on Nylons 4 6 and 6 8. In 2 N 2( N + 1) Nylons, the lengths of the two alkane segments are equal and two different hydrogen-bonded sheet schemes are possible: progres…
The solid state transformation of chitin β into chitin α under the influence of aqueous HCl of increasing concentration was investigated in the case of highly crystalline β chitin microfibrils isolated from the vestimentiferan tube of Tevnia jerichonana . With acid strength below 6 N, the chitin microfibrils remained…
Analysis of the structures in the Protein Databank, released in June 1996, shows that the number of different protein folds, i.e. the number of different arrangements of major secondary structures and/or chain topologies, is 327. Of these folds, approximately 25% belong to the all-alpha class, 20% belong to the all-be…
Abstract Celadonite, glauconite and Fe-illite samples were studied by XRD, EXAFS, IR and Mössbauer spectroscopy. The samples were monomineralic and corresponded to 1 M polytype. In the OH-stretching region of the IR spectra the content of each definite pair of cations bonded to OH groups was determined. The number of…
The restrictions imposed by both chemistry and three-dimensional space on the structures of inorganic crystals can be analysed using the bond-valence model and space-group theory. The bond-valence model is used to construct a bond graph (connectivity table) from which the multiplicities and possible site symmetries of…
The homologous series of 8-fold alkyl-substituted octasilsesquioxane has been prepared by hydrosilation of alkenes with octakis(hydridosilsesquioxane) (HSiO 3/2 ) 8 . Ethene, propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, and 1-decene were employed either in bulk or in toluene solution. The hom…
The evolution of hydrogen bonding with temperature in three copoly(ether−urea)s with no phase separation has been studied by Fourier transform infrared spectroscopy (FT-IR) in the region of the carbonyl absorption of the urea groups. Assignment of the bands was made by supposing the existence of chains of urea groups…
Blends of solutions of poly[2,2‘-( m -phenylene)-5,5‘-bibenzimidazole] (PBI) with poly(amic acids) (PAA's) synthesized from BTDA (3,3‘,4,4‘-tetracarboxybenzophenone dianhydride) and DSDA (3,3‘,4,4‘-tetracarboxydiphenyl sulfone dianhydride) with 3,3‘-DDSO 2 (3,3‘-diaminodiphenyl sulfone), 4,4‘-DDSO 2 (4,4‘-diaminodiphe…