Materials Literature
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Abstract A novel terephthalic acid derivative based on benzocyclobutene, XTA, has been used as a comonomer in the preparation of thermally crosslinkable poly(ethylene terephthalate) copolymers. We have examined the rheological properties of a series of such polymers containing varying monomer percentages of the XTA co…
The thermal expansion characteristics of the reinforcement and matrix constituents in ceramic composites have a strong influence on a number of aspects of the composite performance. Thus the toughn ...
The cofactor specificity of serine hydroxymethyltransferase (SHMT) activities was tested in extracts of several methanogens using tetrahydromethanopterin (H 4 MPt) from Methanobacterium thermoautotrophicum Marburg, tetrahydrosarcinapterin (H 4 SPt) from Methanosarcina barkeri, and tetrahydrofolate (H 4 folate) as the…
Molecular sieves of the type CoAPO-5 have been studied by TEM and ac susceptibility measurements. In the as-synthesised state the material is paramagnetic due to the isolated cobalt ions and microstructurally it looks very homogeneous. After calcination the system develops very small cobalt-containing particles of A s…
Conventional magnetic parameters and Barkhausen noise have been measured in pressure vessel steel samples both as-received and irradiated with doses of up to 10/sup 18/ n/cm/sup 2/. The conventional magnetic parameters, i.e. coercive force, remanence and maximum induction did not change significantly with irradiation,…
Abstract Most solids which are handled in large quantities are stored in the form of small particles, for ease of handling. The storage containers for these solids are generically termed silos, though several other words are in use for special applications. Silos are used in most countries in the world to store a huge…
Hysteretic energy losses which occur for arbitrary, not only cyclic, variations of the magnetic field are the subject of this paper. These losses are derived for the media which can be described by the vector Preisach model of hysteresis. An algorithm for computation of the losses is obtained based on the state diagra…
The oxygen nonstoichiometry, the total conductivity, and the electronic conductivity of were measured by using high temperature gravimetry, dc four‐terminal method, and Hebb‐Wagner's dc polarization technique, respectively. The change in the oxygen nonstoichiometry was explained by assuming Ce' Zr , Ca'' Zr , and as m…
Single crystals of GeS 2 are grown by two methods: crystallization from a melt and chemical vapor transport. All crystals are found to have a monoclinic structure with the unit-cell parameters a =11.45 Å, b =16.09 Å, c =6.7 Å, and β =91°. The reflection and transmission spectra are measured in the region of the absorp…
The X-ray crystal structures of thioindigo derivatives, 4,4‘7,7‘-tetrachlorothioindigo and 4,4‘,5,5‘,7,7‘-hexachlorothioindigo, have been determined to clarify the photocarrier generation process in these compounds. The crystals belong to the same space group ( P 2 1 / a ), but the stacking manner of the molecules dif…
Pure nickel coupons were used as substrates in the deposition of alumina (Al 2 O 3 ) from the reaction of aluminum chloride (AlCl 3 ) with hydrogen/carbon dioxide gas mixtures in the temperature range of 954°–1100°C and system pressures of 2.7–13.3 kPa. The apparent activation energy estimated from the coating growth…
Influence of surface roughness on magnetic properties of Fe/sub 78/Si/sub 9/B/sub 13/ and Fe/sub 78/Si/sub 14/B/sub 8/ amorphous alloy ribbons was investigated. Magnetic induction in an external field of 800 A/m, B/sub 8/ of Fe/sub 78/Si/sub 9/B/sub 13/ ribbon increased slightly with decreasing surface roughness, whil…
The effects of vanadium content, ranging from 0.002 to 0.011 wt-%, and annealing temperature on recrystallisation and grain growth characteristics, texture development, and magnetic properties in cold rolled 0.3% Si electrical steel have been studied.The results indicate that fine VN and VC, precipitated during hot ba…
The linear DC dark- and photo-current-voltage characteristics observed for as deposited (Ts=25°C) and annealed (Ta=70°C) thermally-evaporated selenium s a films in the temperature range 150-300K were used to deduce the respective temperature dependencies of the dark-conductivity σdark and photo-conductivity σph of the…
This paper introduces a newly developed high frequency switchmode transformer consisting of a U-shaped winding and a multiple toroidal magnetic core element structure. The new transformer with adjustable profile structure exhibits a utilization of the core area which is better than a planar core but worse than a pot c…
Significant modifications of the shape of magnetic flux in columns and yokes were observed in the magnetic circuit of four amorphous cores used in a 3-phase transformer. The magnetic losses measured experimentally were significantly higher than the ones calculated theoretically. The values quoted in this paper were ob…
The Hall coefficient, thermoelectric power, and electrical conductivity in PbTe doped with La, Pr, Sm, and Gd are investigated in the temperature range (77–700) K. The impurity atoms act as donors with an electrical activity that increases with temperature until the fraction of electrically active lanthanide atoms (Ln…
Computer simulations of bubble oscillations induced by an ultrasonic wave in liquid nitrogen are performed, including the effect of evaporation and condensation of nitrogen vapor at the bubble wall, that of droplets formation inside the bubble, and that of thermal conduction both inside and outside the bubble. Baghdas…
New enaminoketone metalomesogens with an almost equilateral triangular shape of the mesogenic core have been synthesized. They form either calamitic or columnar mesophases depending on the number and position of the substituted chains. The stability of the columnar as well as of the calamitic phases depends substantia…
The synthesis of a novel kind of form-retaining liquid crystalline crosslinked metallopolymer is reported. Copper(II) is complexed by Schiff's base units as part of a mesogenic side chain polymer. This leads to remarkable antiferromagnetic exchange interactions between the copper centers that are not present in relate…