Luminescence of divalent europium complexes with crown ethers and polyethylene glycols
Divalent europium complexes with crown ethers give a remarkably intense, blue emission under u.v. radiation.
Materials Literature
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Two-dimensional order in the smectic F phase
The smectic F phase of TBPA is characterized by a stacking of weakly coupled pseudo-hexagonal layers. A careful analysis of the shape of the Debye-Scherrer lines enables a comparison to the theoretical predictions concerning the structure of 2d systems : a correlation length of about 250 A has been found within the la…
A magnetic susceptibility study of spin-state transitions in rare-earth trioxocobaltates(III)
Rare-earth trioxocobaltates(III), Ln[CoO3], with Ln = Pr, Nd, Tb, Dy, and Yb exhibit low-spin to high-spin transitions of cobalt characterised by a maximum in the Δχ–1 against temperature plots where Δχ is the cobalt contribution to the magnetic susceptibility. The susceptibility behaviour is distinct from that of La[…
Remarks on Exciton—Phonon Coupling and Exciton Transport
A general theory of exciton (and electron) transport in perfect molecular crystals is discussed. The emphasis is on qualitative results and the elucidation of the effect of exciton and phonon bandwidth on the scattering of excitons and on transport. Various microscopic models are discussed in this light.
Critical behaviour of dark current and spontaneous polarization in ferroelectric SbSI
Dark current and spontaneous polarization, obtained from measurements of pyroelectric current, have been used to study the ferro-paraelectric transition in SbSI crystals. The critical exponent of the spontaneous polarization is found to have the value predicted from a mean field theory (β = 0.51 ± 0.02).
SOIL SURVEY OF WHITMAN COUNTY, WASHINGTON
WHITMAN COUNTY is in the southeastern part of Washington (fig. 1). It has an area of 1,385,370 acres. Most of the county has a rolling to hilly topography and deep soils that formed in silty material deposited by wind. Basalt is the base rock, but there are a few promontories of quartzite, shale, and sandstone. Elevat…
Silver Halide‐Chalcogenide Glass Inorganic Resists for X‐Ray Lithography
Silver halide‐chalcogenide glass composite thin film structures are evaluated as inorganic x‐ray resists at Al line. The sensitivity is shown to be a factor of 2 better than the PMMA 2041 for a 300 nm thick resist layer. A comparable contrast is indicated. A high resolution capability is expected because of the amorph…
How reliable are results of pot experiments?
Results of pot experiments depend much on the environmental conditions under which they are conducted and on “personal factors”; such as the choice of the type of pots, rates of fertilisers applied, the way these fertilisers are applied, growing conditions in the glasshouse, and the decision when to terminate the expe…
Threshold energy for atomic displacement in electron irradiated germanium
n-type germanium has been irradiated with electrons of various energies in the range 0.5 to 3 MeV. Using transient capacitance measurements we observed four majority carrier traps associated with levels at 0.27 eV (E1), 0.39 eV (E2), 0.35 eV (E4), 0.32 eV (E5) below the conduction band. We have studied the variations…
Two-dimensional lattice image of the Mg-base Friauf–Laves phase and a new type of defect
Two-dimensional lattice images have been obtained for the two-, four-, and nine-layer type structures of the Friauf-Laves phase, Mg(Cu0.535Al0.465)2. An intimate correlation is established between the lattice image and the crystal structure. With this relation, layer sequences of disordered stacking regions are determ…
Mössbauer study of the NiFe2O4 precipitation process from a silicate glass
Mössbauer effect measurements were made to study the NiFe2O4 precipitation process from the silicate glass of 50 SiO2–30Na2O–10NiO–10Fe2O3 composition. Both the isomer shift and quadrupole splitting parameters were found to decrease in the NiFe2O4 precipitation process. These decreases were interpreted on the basis of…
A model of electromigration failure under pulsed condition
A model of electromigration failure under pulsed constant-current excitation is derived. Starting with Black’s expression for electromigration failure under dc conditions, the fractional lifetime consumed per infinitesimal time interval is defined as a function of film temperature. The fractional lifetime consumed per…
Piezoelectric properties of internally electroded PZT multilayers
Platinum internal electrodes have been introduced into PZT compositions in a multilayer configuration by a conventional tape casting process. Electrical property data for the devices suggest that the piezoelectric coefficients of the multilayer configuration are approximately 20% lower than those of similar plain PZT…
Nonlinear optics of liquid crystals
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Levitated electrons
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Phosphorus-31 and oxygen-17 n.m.r. evidence of trapped electrons in reduced 18-molybdodiphosphate(V), P2Mo18O62 8?
Reduction of the P2Mo18O626– anion by two electrons results in the mixed valence form and, by using 31P and 17O n.m.r. high resolution spectra, these electrons are deduced to be firmly trapped by two adjacent molybdenum atoms located in both half-units of the anion.
O-D and O-H stretching vibrations in monodomain SrTiO3
The polarization of the three stretching vibration bands of hydrogen or deuterium impurities in the tetragonal low temperature phase of monodomain SrTiO3 and their splitting under applied electric fields allow these modes to be assigned to energetically different positions - one in the (Ti-O)-plane and two with compon…
PHOTOOXYGENATION OF MAGNESIUM meso‐TETRAPHENYLPORPHYRIN*
Abstract— On unsensitized photooxygenation magnesium meso ‐tetraphenylporphyrin underwent oxidative ring cleavage yielding a bilitriene derivative as the sole product. Kinetic studies by quenching technique using singlet‐oxygen quenchers, ß‐carotene and α‐tocopherol, and by substrate direct disappearance technique (Fo…
Fe–B and Fe–Si–B System Alloy Filaments Produced by Glass-Coated Melt Spinning
The melt spinning of Fe–B and Fe–Si–B alloys with a melting point up to 1580 K was carried out and the spinning was successfully performed from a melt at a temperature of 1630 K with winding speeds ranging from 0.95 ms−1 to 7.95 ms−1. The diameters of the filaments obtained were 2 to 13 μm and decreased with increasin…
Further studies of specimen volume changes during processing for SEM: including some plant tissue.
The dimensions of specimens undergoing preparation for examination in the SEM were measured throughout the preparative sequence or at various important stages. The tissues studied included 15-day mouse embryo limbs (MEL), small blocks of adult mouse liver and brain, and potato tuber. The animal tissues were fixed in 3…