Materials Literature
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The investigation of the stems of Thinouia coriacea Britton (Sapindaceae), an ichthyotoxic plant from South Brazil, afforded eight glycosides of oleanolic acid. Structures were assigned based on data from partial hydrolysis. 13C-NMR and mass spectral procedures as 3-O-alpha-L-arabinopyranoside (1), 3-O-alpha-L-rhamnop…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFrom 1-D to 3-D ferrimagnets in the EDTA family: magnetic characterization of the tetrahydrate series MtM(M'EDTA)2.cntdot.4H2O [Mt, M, M' = cobalt(II), nickel(II), zinc(II)]F. Sapina, E. Coronado, D. Beltran, and R. BurrielCite this: J. Am. Chem. Soc. 1991, 113, 21, 7940–794…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGlass temperature of polymer ring systemsArthur Jing Min Yang and Edmund A. Di MarzioCite this: Macromolecules 1991, 24, 22, 6012–6018Publication Date (Print):October 1, 1991Publication History Published online1 May 2002Published inissue 1 October 1991https://pubs.acs.org/do…
The effective elongational viscosity for an oriented fiber assembly of discontinuous fibers suspended in a viscous matrix fluid is developed for a fiber array with variable overalp length of both symmetric and antisymmetric geometries. The results for symmetric and antisymmetric geometries are shown to be equivalent.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOptical and magnetic properties of cobalt(2+) ions in dried and heated silica gels prepared by the sol-gel processKazuo Kojima, Hajime Taguchi, and Jiro MatsudaCite this: J. Phys. Chem. 1991, 95, 20, 7595–7598Publication Date (Print):October 1, 1991Publication History Publis…
Abstract Thermal analysis and wide‐angle x‐ray diffraction were used to assess the crystallinity for a series of poly(vinyl chloride) (PVC) samples, and the use of two complementary techniques was found beneficial. Two polymers were studied; a commercial suspension grade PVC, and an experimental grade of higher syndio…
The thermopower of the organic superconductor \ensuremath{\kappa}-(BEDT-TTF${)}_{2}$Cu[N(CN${)}_{2}$]Br single crystals has been measured in two crystallographic directions a and c within the most conducting organic donor molecule plane. [Here BEDT-TTF represents bis(ethylenethio)-tetrathiafulvalene.] While the thermo…
In the KTiOPO4 (KTP) structure, it is shown that there are hole sites related by pseudosymmetry to the inequivalent potassium sites K(1) and K(2). The formation of twin domains is through a twofold rotation with the principal feature of the twinning being the displacements of the K atoms onto their respective hole sit…
Abstract The clay mineralogy of the Miocene Monterey Formation was determined for onshore and offshore sequences in the Santa Maria basin area, California. The <0.1- μ m fraction of clayey, opal-CT porcelanites, siliceous mudstones, and dolostones from the Pt. Pedernales area consists of mixed-layered illite/smecti…
Previous studies have shown the effectiveness of partially resorbable arterial prostheses in the rabbit. This study compares these same compound prostheses with commercial graft materials in the dog. Conduits 4 mm inner diameter X 50 mm in length were woven from composite yarns containing 69% polyglactin 910 (PG910)/3…
Microstructural and compositional changes during heat treatment of sol–gel‐derived mullite fibers with additions of 2 wt% B 2 O 3 , 2 wt% P 2 O 5 , 2 wt% Cr 2 O 3 , and (1 wt% P 2 O 5 + 1 wt% Cr 2 O 3 ) were compared with those of undoped mullite fibers. For all compositions the sequence of phase development was the c…
Abstract Liquid‐crystalline silsesquioxanes were synthesized by combining mesogens with spherical silsesquioxanes. Most of the synthesized compounds exhibit smectic phases. Lateral connection of a mesogen results in a nematic phase. All phases are optical uniaxial positive, i.e. calamitic structures are favoured. LC‐s…
Chinese NiTi wire was compared with Nitinol and stainless steel wires in a combined laboratory and clinical examination. In the laboratory test, the loading and unloading-deflection properties of the wires were determined in a three-point bending test and their surface properties were studied in a scanning electron mi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCage escape yields in the quenching of tris (2,2'-bipyridine)ruthenium(II) by methylviologen: presence of triethanolamine as a sacrificial electron donorMikhael Georgopoulos and Morton Z. HoffmanCite this: J. Phys. Chem. 1991, 95, 20, 7717–7721Publication Date (Print):Octobe…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotochemically controlled ion permeability of liposomal membranes containing amphiphilic azobenzeneTomoo Sato, Masato Kijima, Yoshihiro Shiga, and Yoshiro YonezawaCite this: Langmuir 1991, 7, 10, 2330–2335Publication Date (Print):October 1, 1991Publication History Published…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPentacoordinate dihydridosilicates: synthesis, structure, and aspects of their reactivityRobert J. P. Corriu, Christian Guerin, Bernard J. L. Henner, and Qunjie WangCite this: Organometallics 1991, 10, 10, 3574–3581Publication Date (Print):October 1, 1991Publication History…
The current status of cobalt-59 NMR spectroscopy is reviewed including historical perspectives and application to various areas of coordination chemistry. Chemical shift data are summarized and tabulated for about 800 complexes from values in the literature and our experimental data. Spin-spin coupling constants are a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIncorporation of aluminum into silicate anions in aqueous and methanolic solutions of TMA silicatesR. F. Mortlock, A. T. Bell, and C. J. RadkeCite this: J. Phys. Chem. 1991, 95, 20, 7847–7851Publication Date (Print):October 1, 1991Publication History Published online1 May 20…
Abstract Permeation and separation characteristics for aqueous alcoholic solutions through a modified silicone rubber membrane containing poly(propylene glycol) in the polymer chain were studied by both pervaporation and evapomeation. Both the permeation rates in pervaporation and evapomeation increase, and the select…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSwitching the mechanism of spin-exchange coupling in (.mu.-oxo)bis(.mu.-carboxylato)divanadium(III) complexes by protonation of the oxo bridgePetra Knopp and Karl WieghardtCite this: Inorg. Chem. 1991, 30, 21, 4061–4066Publication Date (Print):October 1, 1991Publication Hist…