Materials Literature
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The melting line of graphite has been investigated using a method of flash‐heating of small rod of graphite by discharging a bank of capacitors in a 6–8 anvil type high pressure apparatus. The changes of enthalpy of graphite up to the melting point were obtained from the heating energy inserted from a bank of capacito…
The performance characteristics of the ZnO‐Bi 2 O3‐based varistors can be assessed to meet the applications criteria on the basis of a systematic evaluation corresponding to various experimental conditions. This evaluation process employs the lumped parameter/complex plane analysis technique for the ac small‐signal im…
An unsymmetrical donor 4,5-ethylenedithio-4′,5′-(2-oxatrimethylenedithio)-diselenadithiafulvalene (EOST)† has been synthesized. Single crystals of some charge-transfer salts of EOST have been prepared electrochemically. The crystal structures of EOST and its charge-transfer salts were analysed by X-ray crystallography…
An approximate theoretical model of foam spreading on a liquid surface has been formulated. The model is analogous to the spreading of oil slicks on water surfaces. Viscous friction is assumed to be the dominating mechanism in opposing the foam spread. The friction is described by a lumped friction constant. The sprea…
Aconeceras trautscholdi ammonitellae mass occurring in the Aptian of Symbirsk, central Russia represent consecutive calcification stages of the primary organic shell wall. Already after the formation of the organic shell with proseptum, the first whorl and umbilical walls of the initial chamber were calcified, then th…
The pyrrole-based cryptand L, has asymmetric conformation when coordinated to dicopper(I); one-electron oxidation yields a localized mixed-valence dicopper cryptate of the singly deprotonated ligand and two-electron oxidation a dicopper(II) cryptate of the triply deprotonated ligand; single crystal X-ray structure det…
This is a review of glass transition temperature (Tg) measurements of materials by differential scanning calorimetry (DSC). Tg is noted in DSC derived heat capacity (Cp) plots against temperature as the jump in Cp or (∆Cp) that occurs usually over a temperature interval of a few tens of degrees (°C). Under conditions…
Abstract The structure and organization of the organic matrix of the cusps of the major lateral teeth of the chiton Acanthopleura hirtosa have been examined using conventional light and transmission electron microscopy techniques and by using the protein ferritin as an ultrastructural probe. The results show major str…
There are two polymorphic forms of racemic thalidomide. The α-polymorph was formed by crystallization from 2-ethoxyethanol, methanol or dichloromethane, while the β-polymorph was formed by crystallization from a supersaturated solution in refluxing 2-ethoxyethanol. The two polymorphs were characterized by IR spectra,…
The adsorbed species on ZrO2 and CeO2 during CO hydrogenation forming branched carbon chains, especially isobutene, (over ZrO2), have been investigated by chemical trapping, in situ IR, and solid-state NMR methods. These indicated that methoxide and formate were present as the surface species on ZrO2. CO hydrogenation…
Hydrogen concentrations and hydrogen release activation energies from trap sites were investigated for austenitic stainless steels by thermal desorption spectroscopy. It was found that hydrogen concentrations could be determined by the peak areas of the desorption specrta. A spectrum could be separated into four peaks…
Pyrrole can be polymerized within montmorillonite clays via chemical means utilizing Fe3+ and Cu2+ as the oxidizing species. The resultant composite has properties of both the conducting polymer and the host material. Vibrational spectroscopy, thermal analysis and conductivity data all indicate that polypyrrole is pre…
Magnetoelectric effect and piezomagnetism can be considered as related phenomena if we restrict our attention to the antiferromagnetic materials. Both phenomena are connected with a transition of the crystal from a pure antiferromagnetic state into a weak ferromagnetic state. This transition is caused by an external a…
The compositional ranges of Bi4V2O11 solid solutions containing Co, Cu, Zn, Ca and Sr have been determined by means of a phase diagram study at solidus temperatures. Depending on the size of the divalent cation, at least three and probably four mechanisms for accommodating variable cation content have been identified.…
The FTIR spectra of a series of anhydrous copper(II) carboxylates of general formula Cu2[CH3(CH2)nCO2]4(n= 4–8, 10, 12, 14 and 16) have been studied as a function of temperature. The spectra show notable changes associated with the phase transition from the crystalline to the columnar liquid-crystalline phase which in…
The reliability of electrical equipment in high voltage systems can be affected by certain defaults (metallic particles, roughness, etc.) inside the device enclosure. These anomalies may cause a local glow discharge which propagates progressively inside the insulator and which can lead to electrical breakdown. To avoi…
The compounds [Hpy]2[{M(mnt)2}2][M = Fe or Co, Hpy = pyridinium, mnt = maleonitriledithiolate (2,3-disulfanylmaleonitrile)] have been prepared by electrocrystallization and characterized by single-crystal X-ray diffraction, magnetic susceptibility measurements and IR and 57Fe Mössbauer spectroscopies. The compounds ar…
ZnO-based varistors consisting of 96 mol% ZnO and 4 mol% additive oxides (Bi2O3, Sb2O3, NiO, Co2O3, MnO and Cr2O3) have been prepared. Four different procedures have been applied to obtain the starting powder mixture. Three of the procedures involve sol–gel processing of the additive oxide mixture, and in two cases th…
A series of fatigue measurements have been performed on PZT capacitors over temperatures ranging from 78K to 423K. The polarization loss is approximately proportional to the logarithm of the number of fatigue cycles, but the fatigue rate shows a strong temperature dependence, particularly at low temperatures. The capa…
The relationships between the refractive-index and material dispersion of fluoride glasses and their compositions have been studied. A set of parameters was established that can be used to calculate approximately the refractive-index and material dispersion of fluoride glasses. The calculated and measured results agre…