Materials Literature
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A study has been made of the use of optically active additives in twisted nematic devices to remove areas of reverse twist, the results obtained depending on the chirality of the additives and the director alignment on the two containing surfaces. Under certain conditions degeneracy of the field induced reorientation…
Abstract Colour changes of YAG crystals doped with rare earth ions and annealed in hydrogen, oxygen, vacuum or argon are described. The influence of UV irradiation is also given. Some crystals were further doped with Ca, Sr, Ba, or Cr, respectively. Yellow or brown colouring of the crystals is attributed to the O − ce…
This paper describes the principles of a method for the solution of electron optics problems which has led to significant design improvements in traveling wave tubes over the past few years. In contrast to Conventional procedures which solve Poisson's equation on square meshes, the space within the problem boundaries…
The autoxidation of 5-Methyl-5,6,7,8-tetrahydrofolic acid has been studied by kinetic methods and product analysis. The yields of the two major products, 5-methyl-5,6-dihydrofolic acid and 4a-hydroxy-5-methyl-4a,5,6,7-tetrahydrofolic acid, were determined under a variety of conditions. Attempts to observe or isolate p…
A galvanic cell study of the Ca + CaCl2 system is reported. By proper allowance for electronic conduction in the electrolyte phase, the thermodynamic properties have been determined. These data are in good agreement with a vapour pressure study and phase diagram determinations. A model is proposed based upon non-stoic…
Abstract Es wird eine einfache Synthese für 2‐Amino‐3‐cyano‐pyrrole beschrieben, die in der Kondensation von α‐Hydroxyketonen, primären Aminen und Malonitril besteht.
The structure of the title compound has been established by three-dimensional X-ray crystal-structure analysis from diffractometer data. Crystals are monoclinic, space group P21/c, with a= 8·65(1), b= 17·64(1), c= 8·38(1)Å, β= 93·20(10)°, Z= 2. The structure was solved by the heavy-atom approach and molecular paramete…
A simple two-band theory of galvanomagnetic effects in graphite has been developed so as to involve not only the magnetic field intensity ( H ) but its azimuth (θ) with respect to the c-axis, which successfully accounts for the complicated behavior of transverse magnetoresistance (Δρ/ρ 0 ) in an iron-melt graphite pre…
Vitreous silicas containing up to 10% titania are of significant commercial importance because of their low thermal expansions. Instrumental techniques are being developed to determine the structure of the titanium groups in these glasses in order to relate their reduced thermal expansitivities with structural propert…
Simple electron-microscopy techniques are described which allow one to detect the presence of two enantiomorphous forms of a structure within an apparent single crystal. The first method consists of a characterization of the interface between the two enantiomorphs. In the second method advantage is taken of violations…
Different reaction temperatures have allowed the isolation of 1 : 1 and 1 : 2 adducts of phthalocyaninatocobalt(II) with pyridine and 4-methylpyridine. Thermal, vibrational, and magnetic-susceptibility analyses have provided useful information about the structural properties of these complexes; e.s.r. and electronic s…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelenium dioxide oxidation of d-limonene. ReinvestigationHarbo P. Jensen and K. Barry SharplessCite this: J. Org. Chem. 1975, 40, 2, 264–265Publication Date (Print):January 1, 1975Publication History Published online1 May 2002Published inissue 1 January 1975https://doi.org/1…
Abstract The shape of the continuous spectrum between 0.5 and 10 keV generated by 10 to 25 keV electrons has been calculated. It is shown that Kramers' law underestimates the intensity generated at low X‐ray energies. However, this is partially compensated by the greater absorption suffered by continuum X‐rays compare…
The skin interfacing potential of various velours, felts, foams and rough cast surfaces of some polymers was investigated by bonding these substances to solid core silastic rods using Dow-Corning Medical Adhesive Type A. These dummy cannulae were implanted as skin penetrating rods onto the dorsum of canines, goats, an…
A new effective pair potential is proposed. This potential is based on the thermodynamic properties of alkali metal halides in the crystal phase and takes into account the pressure dependence of the compressibility. The form of the new potential is; ϕ(rij)=+ [graphic omitted] + [graphic omitted] exp[–k(rmij–rm0ij)]– […
Tests of 0–90° ply fiberglass roving-epoxy plates, impacted by hard steel cylindrical penetrators, have revealed a sequential delamination mechanism, especially well developed in plates having more than one layer of fibers in each unidirectionally reinforced lamina. In these plates the sequential delamination mechanis…
In order to clarify the effect of heat treatment on the martensitic transformation in the TiNi compound, the electrical resistivity vs temperature curves of TiNi containing hyper-stoichiometric concentration of nickel which were heat-treated under various conditions were obtained. TiNi containing more than 51 at%Ni sh…
Dislocation density, ρ, during steady-state creep of A1–5.54 at.-%Mg alloy was measured as a function of applied stress (oc= 14.7–68.6N/mm2) and of test temperature (T=573–673 K). Effect of the concentration of magnesium (C=0.52–5.54 at.-%) on ρ, was also studied at 573 K. From the present results together with the da…
The T'' phase in the system AI-Cu-Zn has been investigated using electron diffraction, X-ray diffraction, and electronprobe microanalysis. It is established that T'' has a rhombohedral structurewith a==8''676 ÅA and α==27.41∘°. This structure is a superlattice based on an assembly of five small CsCI-type cells, joined…
Spin susceptibility measurements in crystalline alkali+ TCNQ− salts reveal the occurrence of continuous changes and first-order phase transitions in these salts, except Li+TCNQ−. A consideration of the total free energy of these distorted linear systems, in which the electronic energy results from an elementary one-di…