Materials Literature
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The magnetic structure of NiWO 4 has been determined from neutron-diffraction measurements on single-crystal specimens. It is a collinear anti-ferromagnet in which the nickel ions have moments of 2.25 ± 0.04 μ B at 19.4 ± 2.6° to the c axis in obtuse β . The form factor of the Ni ++ ions follows closely the free-ion f…
The crystal structures of Cs2Na[Fe(CN)6](I) and Cs2K[Fe(CN)6](II) have been elucidated by single-crystal X-ray analysis and compared with that of Cs2Li[Fe(CN)6]. Crystals of both are monoclinic, space group P21/n, with Z= 2 in unit cells of dimensions: (I), a= 10.870(1), b= 7.709(1), c= 7.573(1)Å, β= 89.994(6)°: (II),…
Peaks observed in the temperature dependence of the dielectric constant of SrTiO3 glass ceramics do not appear in the dc polarization. A remanent polarization is observed between 4 and 77 K. The dielectric properties at low temperature are attributed to the relaxation of permanent dipoles to an electret state rather t…
The temperature dependence of internal friction was measured from 100 to 350 K at a frequency of about 700 Hz for hydrogen-charged 310S, 316 and 304 stainless steels. A characteristic relaxation peak due to dissolved hydrogen was found at about 280 K, on which there is little information in the literature. The charact…
The physical and functional properties of the mRNA population from developing embryos of the brine shrimp Artemia salina were characterized. About 20% of the total poly(A)-rich mRNA in these embryos appears to be specifically associated with the membrane fraction throughout early development, and physically differs ma…
Local field effects are calculated in the R.P.A. approximation from two extreme points of view. The first consists of an analytical inversion of the dielectric matrix in reciprocal space. If confirms the results of recent numerical calculations, that local field effects tend to reduce the dielectric constant. The seco…
The critical potential of hydrogen absorption and the hydrogen absorption rate into titanium under catholic polarization have been measured in artificial sea water with flow velocity of 2.0m/sec and then the effect of flow velocity, dispersed sand, dissolved zinc ion and dissolved chlorine or oxygen gas on the hydroge…
Streaming due to thermal surface tension gradients — the so-called Marangoni effect in isotropic fluids - has been observed in thin droplets of nematic liquid crystals deposited on a glass substrate. The coupling between the molecular orientation and the hydrodynamic flow induces distortions in the molecular alignment…
Upon irradiation at 366 nm (E)-3-ethoxyiminobutan-2-one undergoes EZ-isomerization. By spectroscopic analysis [i.r., u.v., and n.m.r. (a.s.i.s.)] it was established that the E- isomer exists in the s-trans-and the Z-isomer in the s-cis-conformation. The photostationary state (PSS) ratio obtained by direct irradiation…
A heat-affected zone (HAZ) thermal simulation technique has been used to produce coarse-grained bainite and fine-grained ferrite-bainite microstructures similar to those obtained in the heat-affected zones of single and multipass commercial welds in 0.5Cr-Mo-V and 2Cr-Mo materials. The effects on the HAZ grain size, h…
The reaction of polypyrrole macrocycles with di-µ-chloro-bisdicarbonylrhodium gives rise to out-of-plane mono-(with corroles and thiaphlorins) or bis-dicarbonylrhodium (with porphyrins and azaporphyrins) complexes, depending on the number of imino- and amino-groups present in the central macrocycle cavity. The tautome…
The effect of deformation twinning on the mechanical properties of α-solid solution titanium alloys containing various substitutional elements has been investigated. The results obtained are summarized as follows:(1) Almost all of the twins observed in the specimen deformed below 25°C are identified as {11\bar22}.(2)…
Nematic liquid crystals are well suited as anisotropic solvents in the optical absorption spectroscopy. They make it possible to determine the band polarizations of solute molecules by linear dichroism measurements. With homogeneously aligned nematic phases the investigation can be performed by polarized light, with h…
Powders of twelve alkali halides have been coloured in an electrodeless discharge. Due to the simultaneous production and bleaching of F centres, F aggregate centres could be produced in an adequate concentration. From their study it has been concluded that powders behave as deformed single crystals. It could also be…
Le pouvoir réflecteur d'une surface plane artificielle coupée sur des monocristaux orientés, AgGaSe2 et AgGaTe2, a été mesuré entre 10 cm-1 et 400 cm-1 avec un interféromètre de Michelson avec E // c et E ⊥ c. Les résultats sont analysés par l'inversion de Kramers-Krônig et la méthode de Lorentz. La comparaison des fr…
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The implantation of several different ions into transition metals and transition metal carbides leads to a strong variation of Tc. In molybdenum layers, Tcwas found to increase after implantation of B, C, N, P, As and S ions up to a maximum value of 9.4 K at concentrations of about 25 at. %. No Tcincrease has been obs…
I. INTRODUCTION The various aspects of the degradation of poly(vinyl chloride) (PVC) have been extensively studied [1-10]. This is to be expected considering the wide-spread use of the material in both rigid and flexible plastics, in foams, and in thin films. An understanding of the effects of heat, light, and high-en…
The linewidth caused by the interaction between two-level defects in glasses has been measured through the change in the phase velocity and in the attenuation of a high frequency (9 GHz) ultrasonic wave when another ultrasonic wave of neighbouring frequency propagates in the sample. Experiments were made on several bo…
Ullmann-type condensation of 2,2′-oxydiphenol (2) with o-bromoanisole followed by treatment of the products with hydroiodic acid gave 2,2′-(o-phenylenedioxy)diphenol (4) and 2,2′-[oxydi-(o-phenylene)dioxy]diphenol (6). Similarly, compound (6) gave the homologous pentameric (8) and hexameric (10) diphenols. On condensa…