The primary photochemical reaction step of unsubstituted indolino-spiropyrans
Abstract
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Apatite genesis: A biologically induced or biologically controlled mineral formation process?
Apatite formation from organic matter (ribonucleic acid) and calcium carbonate (cuttlebone) requires intervention of microorganisms. We have attempted to characterize this mineral formation process by locating the alkaline phosphatase and the crystals formed. Alkaline phosphatase, which is important for the liberation…
Phosphonium cascade molecules
Cascade molecules have been synthesized in which the initiation core and branch points of the cascade structure are quaternary phosphonium ion sites.
Instability of the nitrite/iron(III) porphyrinate system
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInstability of the nitrite/iron(III) porphyrinate systemMichael G. Finnegan, A. G. Lappin, and W. Robert ScheidtCite this: Inorg. Chem. 1990, 29, 2, 181–185Publication Date (Print):January 1, 1990Publication History Published online1 May 2002Published inissue 1 January 1990h…
Formation of Organoammonium-Montmorillonites by Solid-Solid Reactions
Abstract Organoammonium-montmorillonites were formed from dehydrated sodium montmorillonite and organoammonium halides by solid-solid reactions. The formation depended on the sizes and counter anions of the ammonium ions used. The behavior was different from that observed in a conventional solution method.
Microwave absorption in Sc- and CoTi-substituted Ba hexaferrite powders
Investigations of hexagonal ferrites as a gyromagnetic medium allow the analysis of phenomena related to ferromagnetic resonance (FMR) in ferrites with high internal anisotropy. In the present work, (Sc)- and (CoTi)-substituted M-type hexaferrite powders are examined on the basis of the general formula BaM/sub x/Fe/su…
Properties of mixtures of silk fibroin/syndiotactic‐rich poly(vinyl alcohol)
Abstract The gelation of mixed solutions of silk fibroin (SF)/syndiotactic‐rich poly(vinyl alcohol) ( s ‐PVA), the thermal analysis of dry‐gels, and the various properties of blend films were investigated. The rate of gelation of a mixed solution was lower than that of each SF or s ‐PVA solution of the same concentrat…
Upgraded Nd-Fe-B-AD (AD=Al,Ga) magnets: wettability and microstructure
An enhanced coercivity of sintered Nd-Fe-B permanent magnets by Al or Ga additions that is associated with a change in microstructure has been demonstrated. These microstructural modifications were detected by energy dispersive X-ray analysis (EDX)-assisted transmission electron microscopy (TEM). Two new ternary phase…
Weak charge-transfer polyoxoanion salts: the reaction of quinolin-8-ol (Hquin) with phosphotungstic acid and the crystal and molecular structure of [H 2 quin] 3 [PW 12 O 40 ]·4EtOH·2H 2 O
Different solvated charge-transfer salts between quinolin-8-ol (Hquin) and phosphotungstic acid have been synthesized and characterized. Spectroscopic data support the presence of a sizeable electronic interaction between electron-rich aromatic organics and the inorganic acid, both in the solid state and in solution,…
Distribution of activation enthalpies in viscoelastic relaxations
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDistribution of activation enthalpies in viscoelastic relaxationsHoward W. Starkweather Jr.Cite this: Macromolecules 1990, 23, 1, 328–332Publication Date (Print):January 1, 1990Publication History Published online1 May 2002Published inissue 1 January 1990https://pubs.acs.org…
Microencapsulation using poly (L-lactic acid) II: Preparative variables affecting microcapsule properties
Poly (L-lactic acid) [L-PLA] microcapsules containing phenobarbitone were prepared from a w/o emulsion system, using light liquid paraffin as the continuum and a solution of phenobarbitone and L-PLA in acetonitrile as the disperse phase. Increasing stirring rate and emulsifying agent concentration were found to reduce…
Water-soluble conducting poly(aniline) polymer
Water-soluble conducting poly(aniline propane sulphonic acid) and its sodium salt have been synthesized by derivatization of polyaniline; multiple and reversible colour changes were observed for polymer films on indium–tin oxide coated glass dipped in a LiClO4/acetonitrile solution between –0.4 and 1.2 V vs. Ag/AgCl,…
Polymeric outdoor insulation
The need for resistance to surface tracking and erosion partially differentiates outdoor insulation from indoor insulation. A review of the current status of development of standards for testing these properties worldwide on materials and components is presented. Of special interest is the self-restoration of the hydr…
Structural Analysis of 3-D Braided Preforms for Composites Part I: The Four-step Preforms
Three-dimensional (3-D) braiding technology using high-performance fibres for advanced composite structures is receiving great attention as a result of the outstanding mechanical and thermoelastic properties of the materials produced. There are now mainly two groups of 3-D braiding techniques, namely, the four-step an…
Adhesion of polyimides to metal and ceramic surfaces: an overview
Experimental and theoretical results on polyimide-to-metal and -ceramic adhesion are briefly reviewed. In general, the polyimide-on-metal interfaces have stronger interactions vis-a-vis the metal-on-polyimide interfaces. A section is also devoted to adhesion promoters and their effect on the adhesion. Data from the li…
Nematic and smectic liquid crystals of hard spherocylinders
We present the phase diagram of a system of hard spherocylinders, including the isotropic liquid and the nematic and smectic-A liquid crystals, calculated with a nonlocal-density-functional model for the free energy. We get first- and second-order nematic--smectic-A transitions, with a tricritical point at L/D=50, and…
Polyhedral oligometallasilasesquioxanes as models for silica-supported catalysts: chromium attached to two vicinal siloxy groups
The reaction of [(cyclo-C6H11)7Si7O9(OSiMe3)(OH)2] with CrO3 leads to the formation of [(cyclo-C6H11)7Si7O11(OSiMe3)CrO2], a new crystallographically characterized silyl-chromate complex that catalyses the polymerization of ethylene in the presence of trialkylaluminium reagents.
A novel method for graft polymerization onto poly(ethylene terephthalate) film surface by UV irradiation without degassing
Abstract A new method omitting oxygen removal procedures from polymerization mixtures was developed for graft polymerization of acrylamide (AAm) onto the surface of poly(ethylene terephthalate) (PET) film with the simultaneous UV irradiation method without photo‐sensitizer. UV irradiation of the PET film with a high p…
Synthesis and structure of [NMe4][CuPt(CN)4]: an infinite three-dimensional framework related to PtS which generates intersecting hexagonal channels of large cross section
[NMe4][CuPt(CN)4] contains an infinite 3D [CuIPtII(CN)4]nn– framework related to the PtS structure, which generates two mutually perpendicular and equivalent sets of hexagonal channels of large cross-section (largest Pt ⋯ Pt diagonal, 13.50 Å) together with large empty square channels perpendicular to the hexagonal ch…
Strong-stretching and Scheutjens–Fleer descriptions of grafted polymer brushes
The analytical theory of the conformations of end-grafted polymer ‘brushes’ is compared to direct numerical solutions of the mean-field equations developed by Scheutjens and Fleer. For moderately large chain length N, the predicted distribution of chain free ends and parabolic monomer density profile are confirmed in…