Materials Literature
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Abstract The rate of attrition of a catalyst sample, of a single particle size, can be expressed by a simple function of initial diameter and time. The initial rate is a function of initial diameter, whereas the decrease in attrition rate of a catalyst of a given size as it ages depends only on time. The attrition equ…
Abstract Homogeneous nucleation followed by diffusion controlled crystal growth was observed in highly supersaturated solutions of BaSO 4 , BaCrO 4 , BaMoO 4 , BaWO 4 , BaCO 3 , PbSO 4 , PbCrO 4 , PbCO 3 , SrSO 4 , and CaWO 4 . In the range of concentrations where the number of homogeneously nucleated particles is lar…
A study is made on the reaction of nitrous oxide with copper surfaces. As with germanium, the reaction has an activation energy that increases with coverage. The transition from surface to bulk oxidation sometimes involves an incubation time. The reaction at 90°C and 20 cmHg gives a coverage of about unity, and is use…
Large single crystals of and can be grown by Czochralski pulling from the melt. In the case of a small amount of excess is used to avoid incongruent crystallization. Both materials show pronounced cleavage very similar to that of mica. The electrical properties of are also very similar to those of mica, making this ma…
Abstract A new expansion cell for the three‐terminal capacitance method is developed. Length changes in the order of 10 −9 cm can be measured at samples of only 4 mm. At first the expansion coefficient of silicon (reference material) is investigated in detail from 20 to 300 °K. The work is completed by interferometric…
This paper treats the development of pertinent theories that establish the properties of the fiber-matrix interface needed to achieve efficient composites and the development of a test technique to measure these properties. An equation is derived that relates the externally applied load to the failure mode, fiber tens…
Abstract The simultaneous diffusion of 64 Cu and 67 Cu has been measured in copper single crystals from 890 to 1061 °C. The strength of the isotope effect f Δ K is 0.684 ± 0.014 and is independent of temperature within the experimental error. This indicates that the contribution of divacancies to self‐diffusion in cop…
Abstract Optical absorption measurements on thick monocrystalline samples of GaSe 1− x S x show that in these mixed crystals the lowest energy gap is indirect in the complete range 0 ≦ x ≦ 1. These results are contrary to earlier reports which indicate that GaSe is a direct gap semiconductor. In the case of GaS the ab…
Metastable glass‐in‐glass separation was observed on rapid quenching of A1 2 O 3 ‐SiO 2 melts containing from 10 to 50 mol% A1 2 O 3 . Nucleation and subsequent crystallization of mullite within the high‐alumina‐dispersed glass phase may occur either during cooling from the melt or on reheating. The metastable binary…
It is shown that a suitable curve fitting procedure can reduce the standard deviation of intensity measurements made with a scanning diffractometer except when the intensity is large in relation to the background level. The procedure has been implemented with an Arndt–Phillips linear diffractometer, on-line to a Ferra…
Abstract Microphase separation occurs in many block copolymers to give domain structures. In this first paper in a series dealing with domain formation and the consequences thereof, a theory is presented for the formation of spherical domains in A‐B block copolymers. The theory establishes criteria for the formation o…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structure of aluminum hydrideJune W. Turley and Harold W. RinnCite this: Inorg. Chem. 1969, 8, 1, 18–22Publication Date (Print):January 1, 1969Publication History Published online1 May 2002Published inissue 1 January 1969https://pubs.acs.org/doi/10.1021/ic50071a005ht…
The critical pitting potential determined potentiostatically of pure Al in 0.1 N NaCl is −0.40V (SHE). This value is not greatly sensitive to temperature (0–40°C), to small alloying additions of Mn or Mg, nor to thickness of oxide film produced by anodizing. The value is more active the higher the Cl − concentration,…
Superplastic extension of the aluminium–zinc eutectoid results primarily from grain-boundary sliding and grain rotation. The strain rate (έ), flow stress (σ), grain size (L), and temperature (T) are related empirically: <disp-formula> <mml:math> <mml:mrow> <mml:mover> <mml:mi>ɛ</mml:mi> <mml:mi>˙</mml:mi> </mml:mover>…
Single‐crystal GaAs , GaP , GaAs 1 − x P x and GaAs 1 − x Sb x films have been grown on GaAs and a number of insulating substrates by the decomposition of alkyl‐gallium compounds in the presence of arsine, phosphine, arsine‐phosphine, and arsine‐stibine mixtures. Both triethylgallium and trimethylgallium have been use…
Some recent developments leading to improved knowledge of the distribution of oscillator strength in the photo-ionization continua of atoms are briefly reviewed. Selective comparisons between the experiments and calculations are indicated. Estimates for attenuation by compounds and solids, insofar as they depart from…
This paper reports studies of the rates of dissolution of natural Brucite, optical grade , and commercial in aqueous solutions. Natural Brucite dissolves by means of a surface reaction requiring protons, and while some protonated ions accelerate the dissolution no inhibitors were found. Dissolution of less perfect is…
n型半導体であるTiO2(ルチル)を電極に用いて分極挙動を測定した。光照射しない時にはカソード分極下で水素発生が起こるが,アノード分極下ではほとんど電解電流が流れず顕著な電解整流作用を示した。TiO2電極表面に光照射すると,カソード電流は変化しないがアノード電流は著しく増加する。この電流はTiO2のバンドギァプ3.0eVに相当する415mμ以下の波長の光によってのみ生じ,また電流の大きさは光強度に比例する。立ち上り電位はpH4.7では-0.5V(vs.SCE)である。この電解酸化反応は従来n型半導体で報告されている電極自身の溶解反応ではなくて,水の電解による酸素の発生であることを確かめた。このことはいわゆる平衡電位より約1V以上も…
M. McPartlin, R. Mason and L. Malatesta, J. Chem. Soc. D, 1969, 334 DOI: 10.1039/C29690000334
Contamination on the surface of high-voltage outdoor insulators can lead to the formation of quasistable gas discharges, which burn in series with the resistive contaminative film. Under certain conditions, these discharges may grow to cause a complete flashover. In this paper, a model for the case of a discharge burn…