Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTComparison of correlation lengths in semidilute polystyrene solutions in good solvents by quasi-elastic light scattering and small-angle neutron scatteringWyn Brown and Kell MortensenCite this: Macromolecules 1988, 21, 2, 420–425Publication Date (Print):February 1, 1988Publi…
Abstract Hollow spherical particles of aluminosilicate having diameters of 80 to 100 Å and high electric charge were synthesized by heating solutions containing Si and Al concentrations of about 2 mM (Si/Al molar ratio = 1.0–1.2; pH = 9.0) at 95°–100°C for 7 days. Electron microscopy, X-ray powder diffraction, and inf…
Abstract Miscible blends of the aromatic polybenzimidazole, poly(2,2( m ‐phenylene)‐5,5′‐benzimidazole) (PBI), and the aromatic polyimide formed from 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride and 3,3′‐diaminobenzophenone (LaRC TPI) have been prepared. Blends with PBI were prepared in N,N ‐dimethylacetamide so…
Laser induced microstructural modification of ductile iron has been studied as a function of processing parameters such as power density and beam–substrate interaction time. The high energy density CO2 laser source changes and refines the microstructure of the near surface layer, leading to enhanced hardness and wear…
A new mineral, ammonioalunite [ideal composition NH4AIlS04)lOH)6], has been found in a sample from the hot-springs setting at The Geysers (Sonoma County), California. Chemical analysis yields 33.0% A1203, 36.0% S03, 12.24% H20, 5.39% (NH4)20, 0.19% K20, 0.17% Na20, and 11.6% Si02. After subtraction of the silica as an…
Abstract A series of polyurea urethane block polymers based on either aminopropyl‐terminated polycyanoethylmethylsiloxane (PCEMS) soft segments or soft segment blends of PCEMS and polytetramethylene oxide (PTMO) were synthesized. The hard segments consisted of 4,4′‐methylenediphenylene diisocyanate (MDI) chain‐extende…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTf-Element/crown ether complexes. 17. Synthetic and structural survey of lanthanide chloride triethylene glycol complexesRobin D. Rogers, Eric J. Voss, and Russell D. EtzenhouserCite this: Inorg. Chem. 1988, 27, 3, 533–542Publication Date (Print):February 1, 1988Publication H…
Anti-inflammatory effects and toxicity of lyophilized extracts of the leaves of Cordia verbenacea DC (Boraginaceae) were investigated through various experimental models in rats. The crude drug significantly inhibited the carrageenin-induced edema proportionally to doses ranging from 0.59 to 2.98 mg/kg. Repeated admin…
<div class="htmlview paragraph">Although water injection or water/fuel emulsions are a well known method of reducing NOx in stationary Diesel engines, their influence on Diesel particulates and particulate SOF has recieved little study. A single cylinder DI Petter engine was used to investigate the influence of…
Abstract Scandium(III) p-toluenesulfonate hexahydrate, as well as the isomorphous yttrium(III) and six lanthanoid(III) (Sm, Gd, Dy, Ho, Er, and Yb) p-toluenesulfonate enneahydrates, were synthesized and their structures were determined by the single-crystal X-ray diffraction technique. The scandium salt was monoclinic…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAxial-ligand control of the photophysical behavior of ruthenium(II) tetraphenyl- and octaethylporphyrin: contrasting properties of metalloporphyrin (.pi.,.pi.*) and (d,.pi.*) excited statesLeanna M. A. Levine and Dewey HoltenCite this: J. Phys. Chem. 1988, 92, 3, 714–720Publ…
Studies of the mechanisms by which cerium dioxide enhances automotive catalyst performance would be facilitated by the use of pure, high‐surface‐area forms of cerium dioxide. A cerium dioxide powder with a BET area of 50 m 2 ·g −1 has been prepared by spray drying an aqueous solution of cerium nitrate, citric acid, an…
We conducted comparative studies on the chemical and mineralogical properties of selected pedons of Spodosols (Placorthods) and Andisols (Fulviudands and Melanudands) derived from Towada-a ash of 1000 B.P. and Chuseri ash of 5000 B.P., Spodosols and Fulviudands of the climosequence showed most remarkable differences i…
Abstract This study examines the effects of crystallinity and temperature on the mechanical properties of PEEK. Crystallinity in PEEK Increases with annealing temperature up to a maximum of 28 percent with a melting point at 335°C. A minor melting peak also occurs about 10°C above the annealing temperature. In cold dr…
The gases released by surface flashovers on alumina ceramics, glass, and quartz, using 20-μs voltage pulses, were investigated using an ion-pumped metal vacuum system. Appreciable quantities of gas were measured (approximately 10−6 Torr liter or 1013 molecules). The composition of this gas differed significantly from…
Abstract The title charge-transfer complex is prepared and its crystal structure is determined (BEDT-TTF: bis(ethylenedithio)tetrathiafulvalene). One third of the BEDT-TTF molecules is incorporated in the anion sheet, and holds about 2+ charge. The remaining donors form a conducting sheet with a similar arrangement to…
We present the synthesis of 2-substituted hydroquinone-bisbenzoates which have large 2-substituents containing aromatic and other ring systems. Contrary to the general accepted opinion these large lateral substituents which cause remarkable deviations from the rod-like shape of the molecules do not prevent the liquid-…
Abstract A nuclear magnetic resonance investigation of the solid zinc chalcogenides ZnX (X = O, S, Se, Te) is carried out, using the following nuclei as probes, 67 Zn, 17 O, 33 S, 77 Se, and 125 Te. The spectra yield nuclear quadrupole coupling constants and chemical‐shift parameters for polycrystalline ZnO and Zns in…
The polymer analogous synthesis of new liquid-crystalline side-chain polymers having polystyrene and poly-α-methylstyrene backbones bearing pendant azo-benzene mesogenic groups is described. The effects of various spacer lengths on the mesophase types were examined. Several liquid-crystalline copolymers were also prep…
Abstract In this study, a theoretical basis for the use of conductive composites was established. A percolation simulation program was used to determine critical area fractions for dispersions of rectangles in two dimensions. Both the aspect ratio and orientations of the rectangles were varied independently, and the s…