Materials Literature
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Abstract By treating α‐olefins/allylsilane copolymers with alkali/alcohol mixtures, ≡SiH bonds of allylsilane units are transformed into ≡SiOSi≡ crosslinking bonds. Soluble or insoluble polymers are obtained depending on whether copolymers to be treated are suitably dissolved or not dissolved in the alkali/alcohol…
Abstract Wegen des Olefincharakters der Butadienpolymeren ist die Alterungsbeständigkeit von schlagfestem Polystyrol unbefriedigend. Alle Versuche, schlagfeste Polystyrole mit gesättigten Elastomeren auf die übliche Art herzustellen, führten nicht zum Ziel. Es wird über Versuche zur Darstellung von schlagfestem Polyst…
From observations on large, single, liquid crystals it has been found that nematic $p$-azoxyanisole exists in two distinct forms: One rotates the plane of polarization of transmitted light clockwise and the other, counterclockwise by the same amount, in analogy to the right- and left-handed forms of quartz, revealing…
Abstract Es wurde eine katalytische Spezifität der Kristallflächen sowohl beim Nickel als auch beim Kupfer nachgewiesen. Die Aktivierungsenergie der p‐H 2 ‐Umwandlung betrug beim Ni an der (111)‐Fläche 3,0, an der (110)‐Fläche 5,2 und an der (100)‐Fläche 6,4 kcal/Mol, beim Kupfer an der (111)‐Fläche 9,1 und an der(100…
In the acid pH region, the relative effects of various salts on the thermal stability of the collagen helix are quite different from their effects at neutral pH. The magnitude of the decrease in thermal stability brought about by the salts studied depends mainly on the nature and concentration of the anion and very li…
Zusammenfassung Im Rahmen kristallchemischer Untersuchungen an Radiumverbindungen wurden eine Reihe von Salzen des Typs RaXO 4 im Mikromaßstab dargestellt und röntgenographisch untersucht. Die folgenden physikalischen Daten wurden bestimmt: [xxx] Alle Salze sind mit den homologen Bariumsalzen isotyp.
The effect of exposure to the laboratory atmosphere on the fracture stress and Young's modulus of poly crystalline magnesium oxide was studied. The observed degradation of mechanical properties was attributed to chemical attack by atmospheric water vapor. The rate and extent of degradation depended on the amount and n…
A study has been made in n-type Bi2Te3+x, n-type Bi2Se0.45Te3+x, and p-type Bi0.5Sb1.5Te3+x of the influence of segregated tellurium phase, determined metallographically, on the thermoelectric figure of merit (Z), electrical conductivity (σ), Seebeck coefficient (α), and thermal conductivity (κ). It was found that Z a…
Abstract Low‐temperature polymerization of α‐piperidone was carried out by using MAlEt 4 , KAlEt 3 (piperidone), and M–AlEt 3 (where M is Li, Na, or K) as catalysts and N ‐acetyl‐α‐piperidone as initiator. The behavior in polymerization of these catalysts was superior to alkali metal or aluminum triethyl, and a polyme…
Vauquelinite, Pb 2 Cu[CrO 4 PO 4 OH], is monoclinic, with a = 13.754, b = 5.806, c = 9.563 Å, β = 94°34′, space group P 2 1 / n . The crystal analysis of the mineral was determined by the trial-and-error method starting from the atomic positions found in fornacite. The refinement carried out by the least-squares metho…
In extension of previous studies of the mechanism of the action of XO4n− inhibitors of corrosion, the behavior of MoO42− ions has been investigated. This inhibitor was found to exert a noncathodic action in facilitating anodic passivation, but the phenomena are more complex than those exhibited by CrO42−, TCO4−, and M…
Cylindrical magnetic lenses were developed with the aim of energy analysis of electrons. A set magnetic pole-pieces with rectangular apertures was inserted into the bore of the intermediate lens of a usual electron microscope and was used as an analyzer lens. It has a large chromatic aberration constant for off-axial…
Three angular variables which give the relative orientation between two sets of axes have been defined and their angular range specified for important classes of symmetry. All possible orientations are contained within this angular volume. Continuous ranges of orientations require a continuous density function defined…
The Adam–Gibbs and the free-volume theories of polymer-melt viscosity and the glass transition are applied to the infinite polymethylene chain by comparing the exponential terms in the respective viscosity equations: 2.3B / (T − T0) = C / TSc = b / φ. It is shown that the configurational entropy Sc and the free volume…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPorphyrin studies. XXXVI. DeoxophylloerythroetioporphyrinEarl W. Baker, Alsoph H. Corwin, Ernst Klesper, and P. E. WeiCite this: J. Org. Chem. 1968, 33, 8, 3144–3148Publication Date (Print):August 1, 1968Publication History Published online1 May 2002Published inissue 1 Augus…
Abstract Hydroxy-Al and -Fe interlayers were prepared in “mono-mineralic” fine and coarse clay montmorillonite and coarse clay and silt vermiculite at 3°C and 21°C. The formation of hydroxy interlayers was evaluated by X-ray diffraction, cation exchange capacity, and chemical analyses. At comparable particle size and…
1. The photosynthetic pigments of the green subsurface layer (Ostreobium) of The pigments found were chlorophylls a and b, α- and β-carotene, siphonein, traces the brain coral Favia were studied by two-dimensional paper chromatography. of siphonaxanthin and neoxanthin, and an unknown yellow-orange xanthophyll. 2. The…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTProcedure for determining the absorption spectra of mixed photochromic isomers not requiring their separationJoseph Blanc and Daniel L. RossCite this: J. Phys. Chem. 1968, 72, 8, 2817–2824Publication Date (Print):August 1, 1968Publication History Published online1 May 2002Pu…
The electrical conductivity and the Seebeck coefficient of single-crystal and polycrystalline NiO were measured as a function of temperature and of oxygen partial pressure over a large part of the phase field of stable NiO. In the temperature range 1000°–1600°C the electrical conductivity was found to be proportional…
Abstract The effect of past thermal history on the melting behavior of isotactic polypropylene is investigated in some detail. It is shown that a series of stepwise annealing treatments at steadily increasing temperatures will raise the final melting point and will result in a double endothermic peak if the final anne…