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A method that uses the analysis of whole X-ray diffraction pattern for determination of the long-range ordering in stoichiometric iron-aluminium-alloy Fe{sub 3}Al is presented. The diffraction pattern of fcc Fe{sub 3}Al can be split into three groups. Intensities of diffraction lines related to the first group are sensitive to the arrangement of atoms at the octahedral positions. Intensities of reflections of the second group vary with a variable distribution of atoms at the tetrahedral positions. Finally, the intensities of diffraction lines that belong to the third group remain constant independent of the stage of the long-order.

We report a case of congenital fibropapillomatosis in the head and neck of a piglet from a swine breeding farm where sporadic cutaneous papillomas of the prepuce and scrotum had previously occurred in several boars. Histologically, the tumor consisted of multiple exophytic, papillary projections composed of branching, densely cellular, fibrovascular stalks covered by hyperplastic keratizing squamous epithelium. Ultra- structural examination failed to reveal viral particles. Cutaneous papillomatosis is rare in swine. To the best of our knowledge, this is the second report of congenital fibropapillomatosis in pigs. Papillomatosis is a self-limiting transmissible disease that in most cases has been shown to have a viral cause. The disease may occur in many domestic and wild animal spe- cies, and it is most common in cattle and horses. 3 Papillo- matosis is rare in pigs, usually affecting the skin and the genitalia. 3 To the best of our knowledge, there is only one case of congenital papillomatosis in the pig previously re- ported in the literature. 4 In this report, we describe a case of congenital cutaneous fibropapillomatosis in the head and neck region of a newborn piglet (crossbred Large White and Landrace). The piglet was delivered by an apparently healthy sow in a litter with an- other nine healthy piglets. There were no large papillary tu- morous lesions in the skin of any other animals on the breed- ing farm; however, there were multiple small warts on the external genitalia of several boars. The piglet was born with a cauliflower-like skin tumor the size of a walnut (3 2 cm) behind the left ear. The tumorous mass grew rapidly, and a malignant cutaneous neoplasm was suspected. The piglet was killed at 42 days of age with bar- biturate (Thiopental, Spofa, Prague). Samples for histopa

Mikrogelhaltige Losungen von Butadien-Acrylnitril-Copolymeren in Butanon wurden viskosimetrisch untersucht. Die Ergebnisse wurden mit Resultaten aus der Lichtstreuung verglichen. Die [η]-Mw-Beziehungen konnen sehr verschiedenartig sein und hagen stark von der Beschaffenheit des Probenmaterials ab. Die Ermittlung von relativen Molekulmassen aus Viskositatsmessungen ist bei solchen Losungen deshalb fragwurdig. Microgel-containing solutions of butadiene-acrylonitrile copolymers in butanone were studied by viscosimetry. The results were compared with data from light scattering measurements. The found [η]-Mw relations are different and strongly dependent on the samples under investigation. Therefore, the evaluation of relative molecular masses from viscosity measurements is questionable when using such solutions.

Aus Messungen des Brechungsindexinkrementes von alternierenden Styren-Maleinsaureanhydrid-Copolymeren in mehreren Losungsmitteln werden die Koeffizienten der Gladstone-Dale-Beziehung fur Poly(maleinsaureanhydrid) berechnet. Unter Hinzuziehung der entsprechenden Koeffizienten fur Polystyren und Polyacrylnitril werden experimentelle und berechnete Brechungsindexinkremente fur Copolymere aus Styren, Acrylnitril und Maleinsaureanhydrid verglichen. Die Fehler von experimenteller Bestimmung und Berechnung sind etwa gleich gros. The coefficients of the Gladstone-Dale rule were calculated for poly(maleic anhydride). The calculation was based upon measurements of the refractive index increments of alternating styrene-maleic anhydride copolymers in several solvents. The experimental and calculated values of refractive index increments of copolymers from styrene, acrylonitrile and maleic anhydride were compared using the corresponding coefficients of polystyrene and polyacrylonitrile. The uncertainty of the calculated data was approximately the same as the uncertainty of the measured values.

The following recent developments in and applications of the classical light scattering from polymer solutions are briefly reviewed: Light scattering photometers; characterization of important polymers; combination of light scattering with other methods; characterization of the degree of branching, particle shape, aggregates, microgels, copolymers, polyelectrolytes, and DNA; thermodynamics of concentrated solutions; solutions of polymer mixtures; interactions in polymer solutions; kinetic measurements; depolarization of scattered light. Some topical problems of the method are discussed, viz, interpretation of curved angular dependences of Kc/Re on sin2(e/2), coupling of light scattering with GPC, and some frequent artefacts.

The method of computing the quasi-isotropic relative structure (QIRS) of a geodetic net which maximizes the relative accuracy between a priori determined points of the net, the configuration of the net being taken into account, is described. The iteration procedure is used to establish this structure.

The effect of Mg, Si, In and Cd solute atoms on the critical resolved shear stress of Cu single crystals has been studied in the “plateau” region in order to complete data on the solid solution hardening of Cu base alloys. Labusch's equation is obeyed both for the concentration dependences and for the dependence of dτp/dc2/3 one4/3. Edge dislocation/ solute atoms interaction dominates in Cu as in Au and Ag base alloys.

The shape of experimental curves CRSS-T (critical resolved shear stress versus temperature) in solid solution crystals is compared with that deduced by Kratochvil et al. [3] and it is shown that at low temperatures agreement is obtained for a certain value of the activation energyU1. So it is possible to find the value of the activation energy of dislocation motionU1 at low temperatures from the CRSS-T dependences.

Age hardening in Cu-9Ni-2Sn and Cu-9Ni-5Sn alloys at 573 and 673 K is studied. After an incubation period (~ 15s) strengthening appears which is due to precipitates in the Cu-9Ni-2Sn alloys. On the other hand an immediate increase of the yield stress characterizes the annealing of the Cu-9Ni-5Sn alloys. This is followed by the regions of constant yield stress and further by a peak. The microstructure of the alloys was studied by means TEM and ED: spinodal decomposition takes place (during quenching) followed by nucleation of the coherent (CUxNi1−x)3Sn particles. Any change of the yield strength can be described by an adequate change of the structure in the sample. The nature of the annealing curves both with a “plateau” and with “double peaks” is discussed. The formula of Labusch can be used to explain the precipitation strengthening.

The stress field of the edge multipole (dipole cluster) in the basal plane is approximated by the superdipole stress field. The stress fields of different dipole (superdipole) arrays are given for anisotropic cadmium crystal. The stress field components into the secondary non-basal slip planes (pyramidal and prismatic) were computed for the same metal. It was shown that the magnitude of this component is comparable with both the value of flow stresses in the secondary systems and the same component of the pile-up stress field.

The results of detailed measurements of osmotic pressure, light scattering, and viscosity of poly(vinyl chloride) solutions are used to establish the molecular weight dependence of [η] and A2, to estimate the unperturbed dimensions of the poly(vinyl chloride) molecule, and to analyze critically the [η]–M correlations published hitherto.

Dislocation loops which are observed in the undeformed sample are believed to originate during crystal growth. Few interactions between them and glide dislocations have been seen after deformation. Formation of triangular nodes and networks of basal dislocations seems to be typical for the sample substantially deformed. The origin of those configurations is thought to be the interaction between different basal dislocations as well as the interaction between dislocation loops growing during the deformation.