Materials Literature
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We have found that the dielectric constant of good single crystals of barium titanate decreases as the average polarization is decreased by means of an electric field. This has been interpreted as being due to a domain clamping effect arising from the multidomain situation in the crystal that accompanies the reduction…
The low-temperature transition in magnetite, according to Verwey, is due to the ordering of the ferrous and ferric ions in the octahedral interstices of the spinel lattice. This arrangement would require a symmetry change from cubic to orthorhombic. X-ray diffraction indicates and electric conductivity and magnetizati…
Abstract The changes in molecular weight of a long-chain polymer (initially of arbitrary molecular-weight distribution) are studied when the main chain is subjected to random fracture, such as occurs when certain polymers are exposed to high-energy radiation. For several distributions studied, all trace of the initial…
Sawaguchi and Kittaka obtained the threshold field of PbZr${\mathrm{O}}_{3}$---that field necessary to change the antiferroelectric to the ferroelectric phase---below the Curie temperature. The free-energy difference is the difference between the area under the ferroelectric portion of the curve and that under the ant…
Summary A dynamic foam test for evaluation of hand‐dish‐washing compositions has been developed which gives good correlation with semipractical plate washing tests. Properties measured in the dynamic tests are foam build‐up index, foaming capacity, and stability of foam to soil.
The vapor pressure of zinc has been measured by the Knudsen effusion method using the radioisotope Zn65. Measurements have been made from 150° to 350°C, and the temperature-vapor pressure relation over this range was found to be log10Pmm=—7198/T+9.664. The heat of vaporization was calculated to be 31.35 kcal per mole…
During investigation of the carotenoids produced by mutant strains of the bacterial phytopathogen Corynebacterium michiganense (E. F. Smith) Jensen The present report summarizes the experiimental work that leads to the conclusion that the C. michiganense pigment is indeed identical with fungal cantha- xanthin. In addi…
The crystal structures of gadolinium, dysprosium, and erbium metals have been determined over a wide temperature range. The metals are hexagonal close packed and the ${a}_{0}$ unit axis contracts nearly linearly with decreasing temperature, whereas the ${c}_{0}$ unit axis exhibits an abnormal expansion with decreasing…
Calculations are made of the first anisotropy coefficient K 1 and of the spectroscopic splitting factor g for nickel, based on the collective electron theory of the corresponding effects due to Brooks and the calculations of the author of the N ( E ) curve for the 3d electrons in nickel. Brooks' theory is reviewed, th…
Data from extensive laboratory anode efficiency tests and supporting field tests illustrate the need for low impurity levels in the 6% Al—3% Zn magnesium alloy cast anodes. Data are presented which show the detrimental effects of the impurities copper, nickel, iron, lead and tin; the beneficial effect of manganese in…
The magnetic moment of dysprosium has been measured in applied fields of 4000-18 000 oersteds, over the temperature range of 4.2-202\ifmmode^\circ\else\textdegree\fi{}K. The susceptibility of dysprosium was found to be field dependent below about 175\ifmmode^\circ\else\textdegree\fi{}K. Below 90\ifmmode^\circ\else\tex…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPermeability of KaoliniteAlan S. Michaels and C. S. LinCite this: Ind. Eng. Chem. 1954, 46, 6, 1239–1246Publication Date (Print):June 1, 1954Publication History Published online1 May 2002Published inissue 1 June 1954https://doi.org/10.1021/ie50534a041RIGHTS & PERMISSIONSArti…
Abstract Polyethylene can be heat‐oxidized in air when temperatures in excess of 125°C. are employed or photo‐oxidized when exposed to ultraviolet radiation during weathering. Infrared spectrophotometric studies show that during these types of oxidation carbonyl groups are formed and the concentrations of the three ty…
The paper gives an account of measurements made on the lattice parameter of cobalt when the material contained crystal grains of different sizes as found in fine dust, filings and annealed solid rod. The stable structure of cobalt was found to depend upon the grain size: between room temperature and about 450°c when t…
The physical characteristics, thermoelectric power, resistivity, specific heat conductivity, and the temperature difference between hot and cold junctions determine the efficiency of thermocouple materials. These data have been determined for Chromel P-constantan, bismuth alloys, and the intermetallic compound ZnSb, c…
An apparatus for making measurements of the Seebeck effect between 20\ifmmode^\circ\else\textdegree\fi{}K and 375\ifmmode^\circ\else\textdegree\fi{}K is described.Experimental curves of the Seebeck effect are given for a series of germanium crystals in which various concentrations of acceptor and donor atoms have been…
A theory is presented for concentration quenching in solid systems, based on the migration of excitation energy from one activator center to another and eventually to an imperfection which may act as an energy sink. Calculations are made on the dependence of the fluorescence yield on concentration, and to indicate typ…
Abstract A new, pressurized high-temperature Debye-Scherrer camera is described. The structures of γ- and δ-manganese are found to be face-centred cubic and body-centred cubic respectively. Accurate curves of lattice-spacing against temperature are given for both these phases, and also for the β-manganese phase, and t…
1. Cells of the fresh water diatom Navicula pelliculosa may be grown in a mineral medium containing a low concentration of silicon. When transferred to a fresh silicate solution and incubated under non-growing conditions such deficient cells rapidly take up silicon from the medium. 2. The utilization of silicon is an…
Abstract The kinetics of the polymerization of the N-carbonic anhydrides of DL-leucine, DL-phenylalanine and sarcosine in nitrobenzene solution have been studied. When preformed polymer is used as initiator, and in the complete absence of water, the first two anhydrides polymerize at rates which show first-order depen…