Materials Literature
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The density-effect correction $\ensuremath{\delta}$ to the Bethe stopping-power formula for fast charged particles is evaluated for metallic aluminum from the dielectric-response function $\ensuremath{\epsilon}(E)$. The latter has been accurately determined over the entire range of excitation energy $E$ by Shiles, Sas…
The dielectric constant, specific heat and thermal expansion of CsHSeO 4 were measured as functions of temperature, and X-ray examination was also made. It was found that CsHSeO 4 undergoes a phase transition at 128°C. The crystal at room temperature is monoclinic with a space group P2/ c . The transition entropy was…
Abstract Gallium hydroxide precipitated from aqueous gallium chloride solution on addition of alkalis at varying pH have been aged in the mother liquors for different periods of time. The resulting precipitates have been examined by X‐ray diffraction and i.r. spectrophotometry. It is found that the precipitate, separa…
A study has been made of the mechanism of dezincijication of α-brass and the effect of azoles as inhibitors for the corrosion of 70/30 brass in sulphuric acid using the weight loss method, solution analysis and electrochemical techniques. The inhibitive efficiency of azoles for the corrosion of α-brass has been found…
The structures of the hydrated zinc(II) and nitrate ions in 4.72 mol dm–3 aqueous Zn(NO3)2 have been determined by X-ray diffraction. Octahedral coordination in Zn2+aq is confirmed and the average Zn—Owater distance is 2.17 (4)Å; there is no evidence for coordination by NO–3. Approximately three water molecules are hy…
Direct measurement of fluorescence quenching rates for various Pr 3+ pairs in weakly doped LaF3 are reported. Since few pairs only are quenched, the transfer mechanism is short range. From the rate values, the shape of the fluorescence decay for heavily doped samples is predicted. The good agreement with the observed…
The cholesteric and “blue” phases (BP) of a mixture of the chiral and racemic forms of the same compound were studied as a function of composition and temperature. It was found that the clearing point and the cholesteric-SA transition temperature was independent of composition. The pitch of the cholesteric at a given…
The polymorphic forms of 2-(2-methyl-3-chloroanilino) nicotinic acid, C13H11ClO2N2, were classified as (I)–(IV) by their i.r. and u.v. spectra, thermograms, and X-ray powder diffraction patterns. Form (I) is monoclinic, space group P21/c, a= 7.625(1), b= 14.201(1), c= 11.672(1)Å, β= 101.65(1)°, and Z= 4. Form (II) is…
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The deformation structure of (211)[\bar111] copper single crystals rolled at room and liquid nitrogen temperatures (RT and LNT) was observed by transmission electron microscopy, and the microstructural process of shear band nucleation was examined. The microstructure prior to the shear band nucleation was composed of…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRate constant and possible pressure dependence of the reaction hydroxyl + hydroperoxoW. B. DeMoreCite this: J. Phys. Chem. 1982, 86, 1, 121–126Publication Date (Print):January 1, 1982Publication History Published online1 May 2002Published inissue 1 January 1982https://pubs.a…
In addition to Sn-rich corrosion products found in conventional amalgams, Cu-rich amalgams also form Cu-containing corrosion products. The nature of these Cu-rich products was investigated by immersion of samples of 13 Cu-rich amalgam systems in Ringer's solution for prolonged periods. SEM/EDS and x-ray diffraction st…
Anisotropic optical absorption of oriented ultrathin films, (down to 50 nm thickness) of low density polyethylene (LDPE) was measured in the vacuum ultraviolet (VUV) region between 6 and 12 eV. Clear anisotropy was found in the observed spectra. The lowest-energy absorption feature at 9 eV was polarized perpendicular…
We study the undulation instability in a smectic A in the presence of shear flow parallel to the layers. We look for the dilation at the threshold where an undulation appears with a wave vector inclined at an angle θ to the direction of flow. We find an integral relation showing that the dilation is necessarily positi…
Water-soluble manganese(III) porphyrins are oxidised in alkaline aqueous solution to the corresponding manganese(IV) porphyrins which, from magnetic moment measurements, appear to exist in solution as µ-oxo-dimers. Midpoint potentials and rate constants for oxidation of the manganese(III) porphyrins have been measured…
The pulse-radiolysis technique has been used to study the reaction of one-electron reducing radicals [CH2OH, CH3ĊHOH and (CH3)2ĊOH] with a series of heteropolytungstates, [PW12O40]3–, [SiW12O40]4–, [FeW12O40]5– and [H2W12O40]6–, to produce the corresponding one-electron reduction products.A gradual decrease in rate co…
A new type of segmented polyurethane (SPU) was synthesized from alpha, omega polyethylene oxide diols (PEG) of MW varying from 600 to 4500, by end capping with 1,4 trans cyclohexane diisocyanate (CHDI) and chain extending with ethylene diamine (ED) in toluene with dibutyl tin dilaurate as catalyst. These SPU are cast…
Analysis of the electronic specific heat constant for some Y(Ni,Al) 5 , La(Ni,Al) 5 , La(Ni,Cu) 5 and Th(Ni,Al) 5 alloys suggests that the amount of hydrogen absorbed in excess of 3 H atoms per RM 5 formula unit (0.5 H atom per metal atom) by the RM 5 phases depends upon the number of unpaired 3d nickel electrons. The…
Sialons are phases in the Si–Al–Q–N and related systems that are built up of (Si, Al)(O, N)4 tetrahedra in the same way that the structural unit in the silicates is the (Si, Al)O4 tetrahedron. These new materials include nitrogen-containing ceramics, glasses, and glass-ceramics but only β’-sialon, the silicon-aluminiu…
The bimolecular rate constant for quenching the triplet excited state of a metalloporphyrin by methyl viologen depends upon the electronic charge on the porphyrin ring. The rate constant increases with increased electrostatic attraction between the reactants and this is due to efficient formation of an encounter compl…