Materials Literature
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Within the liquid crystalline domain, dihydroxysilicon(IV) octakis(dodecyloxymethyl) phthalocyanine is polycondensed to give a distribution of polysiloxanes. These latter form a mesophase with lamellar order. For the first time polycondensation has been carried out in a columnar mesophase and a new type of oligomeric…
Abstract The thermal degradation of a double‐base propellant has been studied to elucidate the rate‐determining steps and the kinetic mechanism in a wide range of temperatures (60°C–200°C) by using modified Taliani test, thermogravimetry (TG), and temperature‐varied Abel (TVA) test. The results indicate that the degra…
Abstract Anion radical salts of bis[1,2,5]thiadiazolotetracyanoquinodimethan (BTDA) containing forty kinds of alkylammonium ions were prepared whose molar ratios are unique for each cation and changed from 1:1 (2A–2L) to 2:3 (2M–2Z), 1:2 (2a–2m), and 2:5 (2n) with elongation of the side chains. The electrical conducti…
A method for the analysis of x-ray diffraction spectra of metallic superlattices using the Monte Carlo technique is presented. Using 'statistical' model of a nonideal superlattice, computer simulation of X-ray spectra has been carried out. The proposed model takes into account a random distribution of superlattice per…
Silver-sodium ion exchange is a commonly used method for making waveguides in glass. This paper discusses two exchange media, KNO(3):AgNO(3) and AgNO(3) in NaNO(3):KNO(3) which increase the flexibility of the process and decrease its cost. Exchange in the KNO(3):AgNO(3) can be performed at temperatures as low as 150 d…
Leitung von Prof. Wolfgang Paul konzipierte und erbaute 500 MeV-Elektronensynchrotron in Betrieb. Es war der erste Elektronenbeschleuniger in Europa, der das damals gerade von Courant, Livingston und Snyder entdeckte Prinzip der starken Fokussierung verwendete. Das Hauptforschungsgebiet lag in den ersten Jahren auf Me…
Electrochromic nickel oxyhydroxide films were formed by an electrodeposition method from 0.005 M NiSO 4 +0.015 M (NH 4 )SO 4 solution, and their memory characteristics, response time and operation lifetime were investigated. The films prepared were porous with a network structure. They were colorless and transparent i…
The surface horizon from a Humo-Ferric Podzol was amended with both CaCO 3 , and P to investigate the changes in the ionic composition of the soil solution and the charge characteristics of the horizon. Addition of CaCO 3 increased the concentrations of Ca and [Formula: see text] and decreased the total concentrations…
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…