Materials Literature
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The calculation of the principal polarizabilities of nematic compounds with reference to the two approaches using either the Vuks formulae or the Neugebauer's relations is discussed. The polarizabilities and internal field constants have been calculated from the birefringence data in the nematic phase of seven compoun…
Abstract The development of impact polystyrene and types of processes used is traced from its inception. Our accidental discovery of the process has resulted in the process being termed unique in that no other commercial polymerization has a like phenomenon that occurs in the shearing agitation step. The prior art and…
University of Michigan, Ann Arbor, Yale University, and The Conneclicut Agricultural Experiment Station, New Haven
Electron spectroscopic (XPS and UPS) studies of the interaction of CO, CO2, O2 and H2O with Mo, and H2O and CO2 with Au are reported. The object was first to explore how far one could distinguish and between different states of chemisorption; whether there was any relation between bond strength and electron binding en…
The known amino acid sequence of the α1 chain of collagen enables the distribution of electric charges along the molecule to be predicted (with the assumptions that the residues, including those in the telopeptides, are uniformly spaced and that the charge distribution in the α2 chain is similar to that in the α1). By…
The diffractometric method has more advantages than the camera technique for X-ray diffraction analysis of the crystalline components of human dental calculus. With the use of this crystallographic method and infrared absorption techniques, it was found that the magnesium content of human dental calculus is the result…
New mesogens have been prepared and studied by differential thermal analysis and optical microscopy to elucidate the effects on mesomorphic properties of replacing a benzene ring by differnt hiterocyclic rings. Earlier workers have assessed the effects on nematic properties arising from such changes in the terminal gr…
The densification behavior of Si 3 N 4 containing MgO was studied in detail. It was concluded that MgO forms a liquid phase (most likely a magnesium silicate). This liquid wets and allows atomic transfer of Si 3 N 4 . Evidence of a second‐phase material between the Si 3 N 4 grains was obtained through etching studies.…
The compositions M II M 2 III ( S , Se ) 4 where M II = Eu , , Ca , Sr , Ba and M III = Al , Ga , In were prepared by reaction of the elements in evacuated silica tubes with iodine as a mineralizer. All members except Ba ( Ga , Al ) 2 S 4 , which is cubic, exhibit the pseudo‐orthorhombic PbGa 2 Se 4 type structure. Th…
Abstract The reaction H 2 → 2 H (dissolved) on thin Pd and Pd‐Ag foils (2.5–5 μm) was studied, with the aid of resistance measurements, in a flow apparatus at temperatures in the range 20–150°C. The rate determining step is the dissociation of the H 2 ‐molecule on the metal surface. It is assumed that in the formation…
Mutants requiring threonine plus methionine (or homoserine), or threonine plus methionine plus diaminopimelate (or homoserine plus diaminopimelate) have been isolated from strains possessing only one of the three isofunctional aspartokinases. They have been classified in several groups according to their enzymatic def…
A group of photoluminescent materials, which may have great influence on future fluorescent lamp development, is surveyed. The materials are based on hexagonal aluminates and gallates which are structurally related to the magnetoplumbites and (β‐alumina. When activated with Mn 2+ , Eu 2+ , Tl 2+ , Ce 3+ , and Tb 3+ ,…
Polyvinyl chloride) (PVC) is undoubtedly among the most frequently used plastics; it is widely applied in many branches of the national economy, including industry and building [1]. Its advantages are comparatively high chemical resistance, low production costs, and an almost universal possibility of application as pa…
Description The Symposium on Zirconium in Nuclear Applications was held 21–24 August 1973 in Portland, Ore., and was co-sponsored by the American Society for Testing and Materials (ASTM) Committee B-10 on Refractory Metals and Alloys and by the Institute of Metals Division, The Metallurgical Society of the American In…
Article Preparation and General Properties of Crystalline Penicillin Acylase from Escherichia coli ATCC 11 105 was published on January 1, 1974 in the journal Biological Chemistry (volume 355, issue 1).
Specialist Periodical Reports provide systematic and detailed review coverage of progress in the major areas of chemical research. Written by experts in their specialist fields the series creates a unique service for the active research chemist, supplying regular critical in-depth accounts of progress in particular ar…
The pressures of SO3 which exist in equilibrium with ferric sulphate have been measured in the temperature range 740 to 975 K by static and dynamic techniques. The overall equilibrium may be described by the two equations Fe2(SO4)3⇌Fe2O3+ 3SO3, 2SO3⇌2SO2+ O2 The equilibrium SO3 pressures above partially sulphated samp…
Above a critical concentration in certain solvents poly-γ-benzyl-L-glutamate (PBLG) forms a lyotropic liquid crystal of the cholesteric structure. In the presence of sufficiently strong electric or magnetic fields this liquid crystal undergoes a mesomorphic phase transition to nematic order. Reported are the results o…
Converted reformer gas on the shell side of a heat exchanger was cooled by water on the tube side. In addition to hydrogen and nitrogen, the gas contained substantial quantities of CO2 and water vapor. The tubes were integral finned of C-steel. Condensate from the gas stream filled the space between fins, while CO2 fr…
En traitant à l'ébullition des mélanges renfermant de l'Hydroxyde d'alumine et des carbonates de magnésium, de nickel ou de lithium, on obtient des composés voisins de l'hydrotalcite. A 60°C, en plaçant les produits initiaux dans des sacs à dialyse, il se forme les mêmes composés associés parfois à des impuretés. Dans…