Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Thermal degradation of polyethylene was studied under a wide range of oxidative degradation conditions including flaming combustion. The collection techniques described were designed to isolate the product mixtures so that secondary reactions were minimized. Both pyrolytic and oxidative degradation products were gener…
In large motors and generators, the surfaces of the stator coils and bars are finished with a partially conducting coating to suppress discharge activity between the insulation surface and the core. However, slot discharge activity has been reported in some air-cooled motors and generators where significant areas of t…
The MoV centre formed by u.v.-irradiation of a single crystal of [NH3Pr]6[Mo7O24]·3H2O has been studied by e.s.r. at room temperature. The e.s.r. spectra are attributed to a localized octahedral MoVO5(OH) site, resulting from transfer of a hydrogen bonding proton from a [NH3Pr]+ nitrogen to a bridging oxygen atom. The…
We adapt to the smectic case the classical lubrication theory; plastic relaxation by edge dislocations climb is the controlling factor of the process, which appears to be more efficient than in the classical case. We show the existence of a critical velocity for the appearance of the undulation instability of the laye…
We give three applications of quasisyrnmetry. The first two applications involve derived conditional distributions in a study involving matched individuals where the parameters associated with the matching are eliminated by appropriate conditioning. Extensions to matched triplets or to larger blocks lead to generaliza…
An electron spin echo (ESE) study of the internal motion of the CH2 protons in irradiated zinc acetate dihydrate crystals shows that quantitative measurements of the motional correlation time can be obtained quite directly from pulsed measurements. In the slow motional limit, the motional correlation time is equal to…
The object of this work was to investigate the influence of long-time aging at elevated temperatures between 300 and 500°C and aging times up to 65 000 h on the impact toughness and the structural properties of CF8 and CF8M cast steels. The results are derived from 18 production heats with varying chemical analysis an…
A Bethe lattice with a given coordination number can be described in terms of a regular tiling of the hyperbolic plane. An interest of this description is the possibility of intermediate lattices between regular lattices in Euclidean plane and Bethe lattices with the same coordination number.
Polymerization of chemically synthesized dn2h6ATP and dn2ATP by deoxynucleotidyl transferase from calf thymus furnished poly(dn2h6A) and poly(dn2A) respectively. The synthetic polynucleotides were characterized by spectroscopic, ultracentrifugation and enzymatic methods. In polynucleotide-polynucleotide interaction, p…
Huit algues du phytoplancton d'eau douce ont été étudiées en culture (6 Chlorophycées, 1 Diatomée, 1 Cyanophycée). Les vitesses d'assimilation de l'azote (NNO<sub>3<sub/>), du phosphore (PPO<sub>4<sub/>) et de la silice ont été mesurées en batch par des expériences de perturbation. Les vitesses maximales d'assimilatio…
57Fe Mössbauer spectroscopy has been combined with bulk results to determine the electronic configuration of iron, the short-range structural order and the magnetic properties of glasses in the system (Fe2O3)x(BaO)y(B 2O3)z. The average coordination of the iron atoms is determined by the Fe/O atomic ratio while the va…
An investigation into the effects of adding cobalt hydroxide to nickel hydroxide electrodes has provided some insight as to why cobalt is an effective additive. The investigative techniques emphasized in situ measurements of electrode mechanical behavior rather than electrochemical data as employed previously. We foun…
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…