Materials Literature
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New satellite features and antiholes in the persistent hole-burning spectrum of N–V centers in diamond, as well as their dependences on applied electric fields and frequency within the inhomogeneous absorption line, are reported. These results, together with reassignments of spin states of this center, permit an under…
Thermodynamic miscibility in high polymer mixtures is almost always the result of specific interactions between the components. However, there are a few blends which exhibit miscibility apparently without any specific
Abstract Previously measured decay rates of HNO in the presence of NO have been kinetically modeled on the basis of thermochemical data calculated with the BAC‐MP4 technique. The results of this modeling, aided by TST‐RRKM calculations for the association of HNO and the isomerization, decomposition, and stabilization…
In thin-film directional solidification of the ${\mathrm{CBr}}_{4}$-${\mathrm{C}}_{2}$${\mathrm{Cl}}_{6}$ eutectic alloy, we observe a quasi-instantaneous transition from symmetric states to drifting parity-broken (``tilted'') states as a result of a sudden increase of the pulling velocity. We show that (i) the observ…
Abstract The accuracy of quantified XPS/AES compositions for a given sample depends on both systematic and random errors. Parameters such as escape depths, transmission functions, sensitivity factors and whether the model of the surface physical structure used in the quantification procedure is appropriate contribute…
We suggest that crystals, when introduced into an organism, may behave as conventional antigens, mediating the production of specific antibodies. These antibodies would bear an imprint of the crystal surface and may consequently behave as a nucleating matrix in a new crystallization event. Thus, they would behave as c…
Flanked by [PW 9 O 34 ] and [WO 6 ] units , the Ni cluster in the salt 1 is magnetically isolated. Within this triangulo Ni cluster, however, ferromagnetic exchange interactions take place. According to magnetic measurements μ eff increases with decreasing temperature to a value of 8.1 μ B mol −1 at 5 K, supporting a…
Abstract Reaction of 1,3-bis(salicylideneamino)-2-propanol (H3L) with manganese(II) acetate tetrahydrate in the presence of ethylenediamine and sodium thiocyanate give a salen complex [Mn(salen)(NCS)] (H2salen = N,N′-disalicylideneethylenediamine), while that in the presence of water and triethylamine gives a binulear…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTwo unique pentacyclic steroids with cis C/D ring junction from Xestospongia bergquistia Fromont, powerful inhibitors of histamine releaseNoboru Shoji, Akemi Umeyama, Kogyoku Shin, Katsuko Takeda, Shigenobu Arihara, Junichi Kobayashi, and Masao TakeiCite this: J. Org. Chem.…
The diatom stratigraphy of Holocene sediment cores from an Antarctic lake (S 67° 48′40″, W 67° 18′50″) on Horseshoe Island has been investigated. The diatom analyses show evidence of a transition from a marine to a brackish to a fresh water environment. The diatom stratigraphy is divided into three different assemblag…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEnantioselective complexation of organic ammonium ions by simple tetracyclic podand ionophoresXuebao Wang, Shawn D. Erickson, Takamasa Iimori, and W. Clark StillCite this: J. Am. Chem. Soc. 1992, 114, 11, 4128–4137Publication Date (Print):May 1, 1992Publication History Publi…
A new ring-A secotriterpene, koetjapic acid [1], and five known compounds, 3-oxo-olean-12-en-29-oic acid [2] (a novel natural product), katonic acid [3], (-)-alloaromadendrene, (-)-caryophyllene oxide, and (+)-spathulenol, have been isolated and characterized from a cytotoxic Et2O-soluble extract of Sandoricum koetjap…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCore expansion, ruffling, and doming effects on metalloporphyrin vibrational frequenciesKristine Prendergast and Thomas G. SpiroCite this: J. Am. Chem. Soc. 1992, 114, 10, 3793–3801Publication Date (Print):May 1, 1992Publication History Published online1 May 2002Published in…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGround-state variability in .mu.3-oxide trinuclear mixed-valence manganese complexes: spin frustrationJames K. McCusker, Ho G. Jang, Sheyi Wang, George Christou, and David N. HendricksonCite this: Inorg. Chem. 1992, 31, 10, 1874–1880Publication Date (Print):May 1, 1992Public…
Abstract Two‐ and three‐component polypropylene (PP) blends and composites were prepared to study their structure/property relationships. Butadiene‐styrene (BDS) copolymers of low compatibility formed large particles of poor adhesion in PP resulting in inferior mechanical properties. Better miscibility of ethylene‐pro…
An explicit solution to the multivariable discrete linear quadratic (LQ) regulation problem is obtained in the limiting singular case where the input weighting matrix tends to zero. Such a solution follows from a suitable spectral factorization of the input spectrum density matrix under the assumption that the system…
High surface area NixAl2-2xO3-2x oxides have been prepared (x = 0, 0.33, 0.44, 0.5, 0.66, 0.85, 1) by a coprecipitation procedure. Both the precipitates and the calcined materials have been characterized structurally by XRD, FT-IR, and TG-DTG analyses. The precipitates are constituted by boehmite (x = 0), by amorphous…
The promoter region of the agarase gene (dagA) of Streptomyces coelicolor A3(2) is complex; it consists of four distinct promoters with different -10 and -35 regions. We report the isolation of a form of RNA polymerase that mediates transcription in vitro from the dagAp4 promoter. The core components of this RNA polym…
Abstract Die supramolekulare Chemie ist ein junges Forschungsgebiet, das rasch der reinen Synthese‐chemie entwachsen ist und das aufgrund seiner Neuartigkeit zur interdisziplinären Zusammenarbeit von Organischer und Anorganischer Chemie, Biochemie, Physikalischer und Theoretischer Chemie und Physik geführt hat. Beruht…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHomopolymer distributions in lamellar copolymer/homopolymer blendsKenneth R. Shull and Karen I. WineyCite this: Macromolecules 1992, 25, 10, 2637–2644Publication Date (Print):May 1, 1992Publication History Published online1 May 2002Published inissue 1 May 1992https://doi.org…