Materials Literature
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Fine powders of ZnFe2O4 with an average particle size of 10 nm and inversion parameter of 0.21 were synthesized by the aerogel procedure. Portions of the powders were calcined in air at 500 and 800 °C and other portions were ball-milled for 10 h. The materials were characterized by x-ray diffractometry, vibrating samp…
We have studied the electronic structure of ${\mathrm{LaCoO}}_{3}$ by photoemission spectroscopy and x-ray absorption spectroscopy (XAS). The Co 2p core-level and valence-band photoemission spectra display satellite structures indicating a strong electron-correlation effect. The Co 2p core-level photoemission, the val…
Laser ablation of (Co,Ni)-doped graphite yields \ensuremath{\sim} 70% single-wall nanotubes, predominantly (10,10) armchair tubes which self-organize into crystalline ``ropes''>100 \AA{} in diameter and>10 \ensuremath{\mu}m long. We find ${\mathrm{\ensuremath{\rho}}}_{\mathrm{\ensuremath{\Vert}}}$=0.03-0.10m\ens…
We show how composites with extremal or unusual thermal expansion coefficients can be designed using a numerical topology optimization method. The composites are composed of two different material phases and void. The optimization method is illustrated by designing materials having maximum thermal expansion, zero ther…
Molecules that behave like large atoms!—molecules of the mixed anhydride formed from the acids tBuP(O)(OH)2 and PhB(OH)2 exhibit this characteristic since in the crystal lattice they occupy the corners and centers of weakly distorted cubooctahedra. The molecules reveal a cubane framework (depicted on the right), whose…
Phosphorus containing polyimides were prepared via phosphorylation of organosoluble polyimides. This was achieved by phenoxaphosphine oxide ring formation reaction or esterification with diethylchlorophosphate. The phosphorylation was confirmed by infrared, 31P nuclear magnetic resonance, and elemental analysis for ph…
The aim of this study was to prepare a compatibilized PP/PBT blend in a twin-screw extruder, using oxazoline-functionalized PP. First we prepared the functionalized PP (PP-g-OXA), and then we used it as a compatibilizer in the subsequent reactive blending stage. Polypropylene was successfully functionalized by ricinol…
100 μm porous p(styrene-co-divinylbenzene) (PS-DVB) microspheres were synthesized by employing a particular membrane emulsification technique, and subsequent swelling of the seed droplets. DVB dissolving a water-insoluble substance, hexadecane (HD), and an initiator was permeated through a SPG (Shirasu porous glass) m…
Bis in die jüngste Zeit wurden die bereits in den sechziger Jahren beschriebenen Ni‐ und Cu‐Corrole als M II ‐Komplexe 1 aufgefaßt (M = Ni, Cu). An dieser Interpretation kamen Zweifel auf, nachdem mit der Existenz von Fe IV ‐Corrolen gezeigt worden war, daß Corrol Metallzentren in ungewöhnlichen Oxidationszuständen st…
Abstract In der Materialforschung arbeiten Ingenieure und Naturwissenschaftler interdisziplinär zusammen. Nach der Entdeckung der wichtigsten heute als Hochleistungskeramiken eingesetzten binären Oxide, Nitride und Carbide im vergangenen Jahrhundert spielte die Chemie in der Werkstoffentwicklung kaum noch eine Rolle.…
Hydrolysis of blend films prepared from amorphous poly(DL-lactide) (a-PLA) and isotactic crystalline poly(D- or L-lactide) (c-PLA) having different c-PLA contents [X = c-PLA/(a-PLA + c-PLA)] was performed in phosphate buffered solution of pH 7.4 at 37°C. The blend films before and after hydrolysis were studied using g…
Two phosphorus-containing diamine compounds, bis(4-aminophenoxy)-phenyl phosphine oxide and bis(3-aminophenyl)phenyl phosphine oxide, were synthesized for use as curing agents of epoxy resins. Phosphorylated epoxy resins were obtained by curing Epon 828 and Eponex 1510 with these two diamine agents. For raising the ph…
Abstract Development of solventothermal methods in the intermediate‐temperature (100–600°C) range has been motivated by current interest in the design of solid‐state compounds with open framework structures. The preparation of nanoporous chalcogenidometalates by this technique is particularly promising, as a combinati…
Near-infrared luminescence is observed from single crystals of K 2 PdCl 4 and K 2 PdBr 4 between 13 500 cm - 1 and 9000 cm - 1 (740 nm and 1100 nm). The emission spectrum of K 2 PdBr 4 shows vibronic structure involving both the totally symmetrical a 1g mode and the non-totally symmetrical b 1g mode ( D 4 h point grou…
A layered mercury telluride, Rb 2 Hg 3 Te 4, was discovered during an exploration of hydro(solvo)thermal synthesis of tellurides at temperatures somewhat above the boiling point of ethylenediamine. Crystals of Rb 2 Hg 3 Te 4 were grown from solvothermal reactions using ethylenediamine as a solvent. Single crystal X-ra…
Raman, X-ray diffraction (XRD), UV−visible reflectance, and 13 C and 109 Ag CPMAS NMR studies have been carried out on three different forms of the layered solid AgS(CH 2 ) 3 CH 3: a white all-trans compound, a bright yellow gauche C(1)−C(2) conformational isomer, and a phase containing both species. The structure of…
A new tungstoboric species, [BW 13 O 46 H 3 ] 8 -, which was identified in solution, is an intermediate between [BW 11 O 39 H] 8 - and the so-called hexagonal acid. This heteropolyacid was obtained in high yield by a new synthetic route. A single-crystal X-ray diffraction study showed that its formula is H 21 [B 3 W 3…
For a series of copper(II) porphyrins, we report EPR data from solid solutions as well as E 0 values for the first ring oxidation, emission spectra, and luminescence lifetimes in methylene chloride. Although the EPR parameters are fairly constant, the potentials vary by almost 700 mV, and the room-temperature lifetime…
The species resulting from a typical preparation for metal-substituted hybrids of the Keggin tridecamer, Al 13 or [AlO 4 Al 12 (OH) 24 (OH 2 ) 12 ] 7+, were examined by performing 27 Al NMR on the solutions during aging and by studying the precipitated sulfate salts via solid state 27 Al NMR and powder X-ray diffracti…
The discrete trinuclear complex [(NEt 4 ){Mn(H 2 O)(5-Cl-salen)} 2 {Fe(CN) 6 }]·H 2 O, 3, and a two-dimensional heterometal assembly [(NEt 4 ){Mn(5-Cl-salen)} 2 {Fe(CN) 6 }] n, 4, have been prepared (NEt 4 = tetraethylammonium, 5-Cl-salen = N, N ‘-ethylenebis(5-chlorosalicylidene)aminato) dianion). Compound 4 crystall…