Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolid-state photooligomerization of an extended chiral bifunctional monomer, (+)-2,4:3,5-di-O-methylene-D-mannitol 1,6-di-trans-cinnamateJoel Bernstein, Bernard S. Green, and Miriam RejtoCite this: J. Am. Chem. Soc. 1980, 102, 1, 323–328Publication Date (Print):January 1, 19…
Abstract Titania gels were prepared by oxidation of precipitates of hydrous Ti III oxide obtained at different pH values from aqueous titanous chloride by the addition of ammonia. The gels were dried at 110–120°C (383–393 K) and their surface properties were characterised by nitrogen adsorption at 196°C (77 K). The ni…
The luminescence emission under X-ray and ultraviolet (UV) excitation of BaTiO3 crystals (obtained by different methods and with various amount of iron doping) has been obtained in a wide temperature range. The temperature dependence of the half-width, position of the maximum and emission intensity of the various band…
The crystal structure of a natural calcium heulandite (Ca)heu and a partially silver-exchanged heulandite (Ag,Ca)heu is reported. The monoclinic crystals, space group C2/m, have cell parameters a= 17.672(6), b= 17.930(6), c= 7.443(4)Å, β= 116.5(1)°, Z= 1, and formula Ca3.1Na1.1K0.1Al7.6Si28.5O72·24H2O (from electron m…
The variation of the periodicity along the $C$ axis (${N}^{\ensuremath{'}}C$) as a function of temperature in ${\mathrm{Fe}}_{9}$${\mathrm{S}}_{10}$, where ${N}^{\ensuremath{'}}$ varies between 5 and 1 over the range 300-600 K, has been investigated. The antiferromagnetic to ferrimagnetic ($\ensuremath{\lambda}$) phas…
Abstract A new detection configuration for the Scanning Electron Microscope (SEM) has been devised, which allows the imaging of the surfaces of a specimen in the open room, i.e., at atmospheric pressure. Such a device gives rise to a new microscope: the Atmospheric Scanning Electron Microscope (ASEM). In this configur…
The effect of preparation method, calcination temperature and sodium content on the dispersion of molybdenum on the surface of γ-Al2O3, as well as on the kind of molybdenum species formed thereon, has been studied using diffuse reflectance spectroscopy (d.r.s), X-ray powder analysis (X.r.), X-ray photoelectron spectro…
Primary cultures of rabbit corneal endothelial cells were labeled with proline and the medium proteins were fractionated by sedimentation through sucrose density gradients. A new collagen, endothelial cell (EC) collagen, was completely separated from type IV collagen without denaturation by this technique. Sodium dode…
We report magnetic susceptibility (χs) data from 2.6 to 300 K for ten quasi one-dimensional organic conductors, most of which obey the law χs = AT-α with α ≃ 0.7 below about 20 K. Results for irradiated TTF-TCNQ and other évidence indicate that such behaviour can occur for a small concentration of unpaired spins at th…
A measurement of the thermal conductivity and the specific heat of pure and iodine doped samples of polyacetylene (CH)x are presented here. The thermal conductivity of pure (CH)x is about 75 mW/cm . K at room temperature and decreases monotonically to 1.6 mW/cm . K at 25 K. The specific heat dependence with temperatur…
The paper reviews the existing experimental evidence for irradiation induced re-solution and also possible explanations for the mechanism. The importance of re-solution is considered with regard to intragranular bubbles and the accumulation of gas on grain boundaries. It is concluded that re-solution is most effective…
Thermoluminescence spectra of CaS:Bi dosimeter have been recorded for the two glow peaks occuring at 60°C and 200°C. Due to the presence of two groups of traps, retrapping mechanism has been investigated in order to get the best performance out of this dosimeter. The effect of annealing, storage and pre-heating on the…
Divalent europium complexes with crown ethers give a remarkably intense, blue emission under u.v. radiation.
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…
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[…
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.
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).
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 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…
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…