Materials Literature
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Abstract : A performance analysis of the thermochemical/thermomechanical behavior of graphite is made extending present analysis procedures to include the allotropic features of bulk graphite. The analysis comprises a complete definition of graphite sublimation, and formulates a model for mechanical erosion based on e…
The procedure of Roe for describing the crystallite orientation in polycrystalline samples having general texture is tested using two samples of biaxially drawn polyethylene. An automated four-circle diffractometer was used to obtain 12 pole figures (4332 fixed points) for the film having stretching ratios 3.0 × 2.0,…
We have measured the electron paramagnetic resonance and optical absorption properties of several complexes of copper(II) in which the ligands of the copper atom are two nitrogen and two sulfur atoms. Chelate structures varying from two saturated rings to a three-condensed-ring pseudoaromatic system have been explaine…
Sodium borohydride reacts with sulfur at room temperature in the presence of appropriate organic solvents to give a sulfurated borohydride: NaBH 2 S 3 . The formulation of this hydride has been established by infrared, nuclear magnetic resonance, and elementary analysis. Thermal decomposition and hydrolysis are report…
A new reflective optical storage effect has been found in mixtures of certain nematic liquid crystals and cholesteric liquid crystals. When subjected to a dc field, the initially clear material becomes milky white and remains in this state when the field is removed. The material can be rapidly switched back to its cle…
The viscosity of B2O3 glass was measured from 1010–1014 P by the fiber-elongation method and found to be Arrhenius with an activation energy of 94 kcal/mol. These new data were combined with previously reported rotation data (101–1010 P) and gave a smooth plot. The complete viscosity data were used to test the equatio…
The optical constants of V${\mathrm{O}}_{2}$ have been determined between 0.25 and 5 eV both below and above the semiconductor-metal transition temperature ${T}_{t}=340\ifmmode^\circ\else\textdegree\fi{}$K. Reflectivity and transmission spectra have been measured on both single crystals and than films. The reflectivit…
The generalized magnetic susceptibilities, $\ensuremath{\chi}(\stackrel{\ensuremath{\rightarrow}}{\mathrm{q}})$, have been calculated along the line $\ensuremath{\Gamma}$ to $A$ for the heavy rare-earth metals, Gd, Dy, Er, and Lu, using energy bands previously calculated by Keeton and Loucks. The initial ordering peri…
We have studied the excitation of plasmons by energetic electrons, and their subsequent decay, in small spheres. We estimate that plasma decay light from electron bombardment of small, randomly distributed metal spheres suspended in a dielectric medium may be emitted with intensity comparable with that found in experi…
The phase transition from nonpolar to polar in displacive ferroelectric crystals is accompanied by the displacement $\ensuremath{\Delta}z$ of certain atoms from their higher-temperature symmetry positions. A study of all displacive ferroelectrics in which atomic positions have been determined has shown that a fundamen…
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…