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Abstract Thermosetting arylimides were prepared by reaction of sulfone ether diamines with maleic anhydride followed by chemical imidization of the intermediate polyamic acid with acetic anhydride/sodium acetate. These arylimides could be thermally cured to afford heat stable systems possessing high glass transition t…
Polymethylmethacrylate specimens are loaded by a flat-ended punch, both by impact and using an Instron machine. The deformation is compared with that produced in similarly loaded titanium and copper specimens and with related work by other researchers. It is found in these experiments that deformation occurs in locali…
Abstract The layer structure of kaolinite from Twiggs, Georgia and fire-clay type kaolinite (Frantex B, from France), particle size separates 2–0·2 μ m was studied by high resolution electron microscopy after embedment in Spurr low-viscosity Epoxy media and thin sectioning normal to the (001) planes by an ultramicroto…
The substitution reactions of tetrakis(4-N-methylpyridyl)porphinecobalt(III)(CoTMpyP) with pyridine have been studied as a function of pH at 25° and an ionic strength of 0.5 M. The mechanistic pathway proposed for the thiocyanate substitution reactions is applicable to pyridine as well. A pyridine axial substituent ha…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFluxional, catalytically active metal cluster, heptakis(tert-butylisocyanide)tetranickelV. W. Day, R. O. Day, J. S. Kristoff, F. J. Hirsekorn, and E. L. MuettertiesCite this: J. Am. Chem. Soc. 1975, 97, 9, 2571–2573Publication Date (Print):April 1, 1975Publication History Pu…
Abstract Bei der Darstellung von koordinativ ungesättigten Cr(II)‐ Oberflächenverbindungen führt Variation von T akt und/oder T red zu unterschiedlicher Reaktivität der Produkte, bezogen auf gleichen Oberflächen‐Cr(II)‐Gehalt. Es wird ein Parameter Q definiert, der den (mittleren) „ungesättigten Charakter”︁ der Oberfl…
Abstract In the preceding paper, general equations were established for the motions of chains confined to a tetrahedral lattice. In the present paper, bond orientation correlation and autocorrelation functions are explicitly calculated for the case where only three‐bond elementary motions are considered. Effects due t…
Abstract The elastic free energy for a tetrafunctional network is here expressed as where λ 1 , etc., are the principal extension ratios relative to the state of reference (wherein 〈 r 2 〉 = 〈 r 2 〉 0 ), and C 1 , C 2 , and m are arbitrary parameters. The free energy of a swollen system is taken to be the sum G = G mi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNitroxides. LXX. Electron spin resonance study of cyclodextrin inclusion compoundsJ. Martinie, J. Michon, and A. RassatCite this: J. Am. Chem. Soc. 1975, 97, 7, 1818–1823Publication Date (Print):April 1, 1975Publication History Published online1 May 2002Published inissue 1 A…
Abstract The relaxation kinetics of a staggering zipper model are presented, in which the formation of helical nuclei is regarded to be rate‐limiting and in which the sliding of strands along the helices is prohibited. Instead a realignment of staggered chains is only possible via complete uncoiling. While maintaining…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydrogen bonding interaction of some naturally occurring isomeric juglones with dioxaneS. B. Padhye and B. A. KulkarniCite this: J. Phys. Chem. 1975, 79, 9, 927–928Publication Date (Print):April 1, 1975Publication History Published online1 May 2002Published inissue 1 April 1…
Abstract Differential thermal analysis in hydrostatic apparatus yielded for K 2 CO 3 : solid‐liquid transition (905 ± 2°C intercept at 1 bar), 20.2 ± 0.6 deg kbar −1 slope and solid‐solid (421 ± 2°C), 16.8 ± 0.8 deg kbar −1 , to ∼5 kbar; Na 2 CO 3 : solid‐solid (485 ± 3°C), 15.5 ± 0.5 deg kbar −1 and solid‐solid (356…
A method is proposed for constructing in general form an analytic approximation to the energy distribution function g(ϵ) of spin waves in an ideal Heisenberg ferromagnet. The method is based on the construction of subspaces which are invariant under the Heisenberg operator, which enables one to express the function g(…
Abstract EPR and matrix ENDOR spectra have been examined for polyenyl radicals in γ‐irradiated PVF, PVF 2 , PVC, and PMMA polymers. Proton matrix ENDOR is observed for all four polymers, and fluorine matrix ENDOR for PVF and PVF 2 . By line shape analysis of the ENDOR spectra obtained under comparable conditions, delo…
Abstract ABS (acrylonitrile‐butadiene‐styrene) plastics are one of the most common two‐phase commercial polymer systems. They consist of a continuous rigid phase (styrene‐acrylonitrile co‐polymer) in which the elastomer phase (polybutadiene grafted with styrene and acrylonitrile) is finely dispersed in the form of sph…
The electrical resistivity of silver foils 15−25 μm thick was measured during shock−wave compression between sapphire anvils in the pressure range 25−120 kbar. Comparison of isothermal resistivity vs compression from shock measurement to a simple semiempirical calculation of resistivity under hydrostatic compression s…
Ductility is a property of a material which has been defined by many investigators who have employed a variety of measurements or indices. The purposes of this paper are to describe some of these indices with emphasis on those employed at elevated temperature and to discuss some of the correlations with particular mat…
Designers of critical devices and machines are frequently confronted with the need to compromise between available materials which will resist, simultaneously, mechanical wear by elements in contact and corrosion by a process environment. These two qualities have long been mutually exclusive from the materials selecti…
Thirty-six steers, divided equally between Angus and Charolais breed types, were slaughtered after 153 (Group I) and 233 (Group II) days on a standard finishing ration. A 3.81 cm steak from the longissimus from the seventh thoracic rib region was removed from the left wholesale rib 48 hr postmortem and used for histol…
Abstract The Raman spectra of (NH 4 ) 2 SO 4 single crystals have been recorded and measured using an Ar + laser as a scource of excitation. The polarization behaviour of the Raman lines in different crystal orientations has been studied. The observed shifts in the range 15–3400 cm −1 have been attributed to the phono…