Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPoly(ether ketone)s by Fluoride Catalyst SystemsU. Hoffmann, F. Helmer-Metzmann, M. Klapper, and K. MuellenCite this: Macromolecules 1994, 27, 13, 3575–3579Publication Date (Print):June 1, 1994Publication History Published online1 May 2002Published inissue 1 June 1994https:/…
A simple method is presented for the determination of the rotational viscosity of nematic liquid crystals. Theoretical expressions for the rotational viscosity from transient displacement current in nematic liquid crystals are derived. The validity of the expressions is numerically examined. It is found that the rotat…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLarge-Ring S6-Thiacyclophanes as Ditopic Macrocycles. Synthesis and Structures of 2,5,8,17,20,23-Hexathia[9.9]-o-cyclophane, HT[9.9]OC, 2,5,8,17,20,23-Hexathia[9.9]-m-cyclophane, HT[9.9]MC, and [Ag2(CH3CN)2(HT[9.9]OC)][BF4]2Broer de Groot, Stephen J. Loeb, and George K. H. S…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectric Double Layer near Soft Permeable Interfaces. 1. Local ElectrostaticMarina Belaya, Victor Levadny, and David A. PinkCite this: Langmuir 1994, 10, 6, 2010–2014Publication Date (Print):June 1, 1994Publication History Published online1 May 2002Published inissue 1 June 1…
Abstract A mathematical model has been developed for the prediction of the optimum design of packed and plate columns for the manufacture of nitric acid. The effects of inlet NO x composition, extent of oxidation and extent of absorption in each stage, temperature, and pressure have been included in the model. The opt…
Abstract The crystals of 2-iodoanilinium picrate have three polymorphic forms. The crystal structures of the monoclinic form (form I) and the triclinic form (form II) have been determined by the X-ray diffraction method. The crystals of the third form (form III) are unstable. In forms I and II, 2-iodoanilinium cation…
The crystal structure of kalipyrochlore from the Lueshe carbonatite, Zaire, Fd3m, a 10.604(1) A, has been refined to an R of 1.62% (wR = 1.65%) for 100 observed reflections (MoKa radiation). On the basis of electron-microprobe and X-ray-diffrac tion data, the formula is ([H201o.99SrO.OSCaa.olh:J.os(NbJ.80Tio.2o)l:2(0…
We have investigated the evolution of transient structures in the twist Fr\'eedericksz transition of low-molecular-weight nematic liquid crystals. Planarly aligned cells have been exposed to an in-plane external magnetic field perpendicular to the initial director orientation. The formation of periodic structures was…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGround-State Electronic Structures of Binuclear Iron(II) Sites: Experimental Protocol and a Consistent Description of Moessbauer, EPR, and Magnetization Measurements of the Bis(phenolate)-Bridged Complex [Fe2(salmp)2]2-Michael P. Hendrich, Edmund P. Day, Chiou-Pirng Wang, Ba…
Abstract Intercalation of macrocyclic compounds (crown-ethers and cryptands) in 2:1 charged phyllosilicates is a topotactic reaction, the lamellar structure of the pristine material being preserved. X-ray diffraction and spectroscopic (IR, NMR) results provide information on the main structural characteristics of the…
A review of experiments and theoretical descriptions for the order-disorder phase transition in MSCN (M = K, Rb, NH4, Tl) is given. These crystals which have an appealing structure exhibit a phase transition from an orthorhombic low-temperature phase to a tetragonal high-temperature phase at elevated temperatures. Emp…
A nove approach to mesomorphism is reported in which discotic pyrazole derivatives are formed by dimerization of half‐disk‐shaped promesogenic pyrazoles throught BH 2 bridges. The figure show the texture of the D hd mesophase exhibited by one of the resulting pyrazoboles. How the mesomorphism is affected by the number…
Monoclinic ZrO 2 has been milled for various times down to a crystallite size of 145 Å. Using the time‐differential perturbed‐angular‐correlation technique, it was possible to associate the resulting growing amount of disordered material with two different, very distributed and milling‐time‐dependent hyperfine interac…
A reflection grating with a binary surface profile is presented that has high diffraction efficiency. The measured intensity for the + 1st diffracted order was 77%. The binary grating is composed of a minilattice with feature sizes comparable with the wavelength of the incident light. The overall structure is designed…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis, Characterization, and Properties of Covalently Bound, Self-Assembled Porphyrin Multilayer Thin FilmsDeQuan Li, C. Thomas Buscher, and Basil I. SwansonCite this: Chem. Mater. 1994, 6, 6, 803–810Publication Date (Print):June 1, 1994Publication History Published onli…
Abstract The close approach of the fluorine nuclei in the difluorinated syn ‐[3.3]metacyclophanes 1, 2 and their [2.2] analogues 3, 4 leads to strong 19 F, 19 F spin‐spin interactions which obey a through‐space mechanism. The geometries of 1–4 were estimated by MM2 molecular mechanics computations, those of 1 and 3 we…
ZnO solidus and liquidus boundaries in the ZnO‐Bi 2 O 3 system were investigated via analytical electron microscopy (AEM), electron probe microanalysis (EPMA), and secondary ion mass spectrometry (SIMS). The Bi 2 O 3 solubility is highest—0.24 ± 0.04 mol%—at the eutectic temperature of 740°C and decreases rapidly with…
Abstract A joint project of different european aircraft manufacturers involves the investigation of the involvement of microorganisms in corrosion damage in aircraft. In a first step, the microflora of corrosion failures was investigated. Swab samples were taken from corroded sites and were cultured on different media…
Lead titanate particles of controlled size around the nanometer range were prepared by hydrolyzing a mixture of the constituent metal alkoxides. The hydrolysate powder was crystallized by calcination into a tetragonally distorted perovskite structure. The hydrolysate started to crystallize by calcination at 470° C for…
The amount of IIAGlc, one of the proteins of the phosphoenolpyruvate:glucose phosphotransferase system (PTS), was modulated over a broad range with the help of inducible expression plasmids in Salmonella typhimurium. The in vivo effects of different levels of IIAGlc on glycerol and maltose metabolism were studied. The…