Untersuchungen zum Dehnungsverhalten von Polybutylenterephthalat (PBT)-Folien

Zusammenfassung Anhand von Röntgenuntersuchungen wurden dehnungsund belastungsabhängige Veränderungen der PBT-Ketten-konformation untersucht. Die Faseridentitätsperiode (FIP) des PBT vergrößert sich beim Dehnen oder Belasten diskontinuierlich, der Blättchenebenenabstand verkleinert sich dagegen kontinuierlich. Die auftretenden Gitterstörungen, deren Modell diskutiert wird, werden durch Veränderungen der Kettenkonformation hervorgerufen.Die von den anderen Autoren gefundene-Struktur des PBT wurde nur bei hoch gedehnten ( = 18%) PBT-Proben nachgewiesen, kann aber zur Erklärung der Umwandlung der PBT-Kettenkonformation nicht herangezogen werden.

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Summary Stress and strain induced changes in the chain conformation of polybutylene terephthalate (PBT) were determined by X-ray measurements.The fibre identity period (FIP) increases discontinuously with stress or strain, whereas the (100) Bragg spacing (Blättchenebenenabstand) decreases continuously.Lattice distortions are due to these changes in the PBT chain conformation. A model of these lattice distortions is presented and discussed.The so-called-structure of PBT given by other authors exists only in the case of highly strained ( 18% PBT fibres.The changes in the PBT chain conformation cannot be attributed solely to the existence of the-structure.

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Mit 12 Abbildungen und 2 Tabellen     

Frequency-dependent linear response of superconducting systems

We present a density functional scheme for calculating the frequency-dependent linear response of superconductors. The central result is a set of integral equations determining the linear response of the normal and anomalous densities to external perturbations. Analytic solutions of these integral equations are obtained for homogeneous systems with separable effective interactions. For inhomogeneous superconductors, the formalism leads to a scheme for calculating the critical temperature without explicitly solving the gap equation. © 1995 John Wiley & Sons, Inc.     

[(C6H5)3P]2Ni(Me3Si?CC?SiMe3). Darstellung,Eigenschaften und Struktur des ersten stabilen Nickel(0)-Komplexes von Bis-trimethylsilylacetylen

[(C₆H₅)₃P]₂Ni(Me₃Si? C?C? SiMe₃). Preparation, Properties, and Structure of the First Stable Nickel(0) Complex with Bis(trimethylsilyl)acetylene The title compound is the first example of a nickel(0) complex with bis(trimethylsilyl)acetylene and obtained from (ph₃P)₂Ni(C₂H₄) and bis(trimethylsilyl)acetylene in tetrahydrofuran. The complex is characterized by some reactions, the i.r. spectrum and by a structural analysis with the aid of X-ray diffraction data. (ph₃P)₂Ni(Me₃Si? C?C? SiMe₃) crystallizes monoclinic in the space group C2/c with four formula units per unit cell (2468 observed, independent reflexions, R = 0.038). The cell dimensions are a = 20.927, b = 13.812, c = 14.238 Å, α = γ = 90°, β = 91.02°. The molecules are monomer in crystalls. The molecule is planar with ligands arranged trigonally about the central atome but distorted to the tetrahedral complex.     

Structure investigations on the hot-working behaviour of steel

Structure changes occurring in hot-deformation of the austenite of steel, the - phase transformation of which takes place above room temperature, cannot directly be studied with quenched specimens. However, within certain limits a microstructure characterization is possible by means of investigation of carefully selected model alloys and/or by analysis of the microstructure inheritance associated with a martensitic - transition of the hot-worked austenite. Application of both procedures is demonstrated with results which were obtained in investigations of the hot-working behaviour of low-alloy spring steel and an Fe-Ni-C model alloy.     

Effect of hydrostatic pressure on the static susceptibility of the spin-glass systems Ag:Mn,Au:Mn,Cu:Mn and Au:Fe

Previous studies of the magnetic susceptibility of a Ag-3 at.% Mn spin-glass under high pressure are extended to include the systems Au-3at.% Mn, Cu-3at.% Mn and Au-3at.% Fe. In all four alloys the spin-glass freezing temperatureT ₀ increases with pressure, yielding the volume dependences lnT ₀/ lnV=–3.6±0.4, –4.1±0.6, –2.1±0.4 and –1.64±0.25, respectively. These results give information about the nature of the interaction mechanisms responsible for the spin-glass freezing phenomena. The pressure dependence of the Curie temperature of ferromagnetic Au-20at.% Fe was also studied.Dedicated to B. Mühlschlegel on the occasion of his 60th birthday     

Triphenylphosphan-Nickel(0)-Komplexe mit Isocyanid-Liganden — [(RNC)nNi(PPh3)4–n] (n = 1–3)

Triphenylphosphane Nickel(0) Complexes with Isocyanide Ligands — [(RNC)_nNi(PPh₃)_4–n] (n = 1–3) Synthesis and properties of the isocyanide triphenylphosphane nickel(0) complexes [(RNC)Ni(PPh₃)₃], [(RNC)₂Ni(PPh₃)₂] and [(RNC)₃Ni(PPh₃)] (R = ^tBu, Cy, PhCH₂, p-TosCH₂) are described. I.r. and ³¹P n.m.r. spectra were recorded and the X-ray crystal structure of [(PhCH₂NC)₂Ni(PPh₃)₂] was determined.     

Metabolites of the pathogenic fungusVerticillium dahliae III. The lipid composition ofVerticillium dahliae

Summary The compositions of the neutral lipids of the mycelium and of the culture liquid from the pathogenic fungusVerticillium dahliae Kleb. have been investigated for the first time. The fatty-acid compositions of the main lipid fractions and the glyceride composition of the triglyceride fraction have been determined. The main acids of all the fractions are the 16:0 and 18:1 acids and in the triglyceride fraction, additionally, the 18:2 acid. Diisobutyl phthalate has been found in the combined neutral lipids of the fungal mycelium.V. I. Lenin Tashkent State University, Institute of the Chemistry of Plant Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 431–435, July–August, 1976.     

Reaction of 4-methyl-5,6-dihydro-2h- and 4-methylenetetrahydropyrans with phenylsulfinyl chloride

4-Methyl-5,6-dihydro-2H- and 4-methylenetetrahydropyrans undergo an ene- type reaction with phenylsulfinyl chloride in the presence of ZnCl₂ to give the corresponding allylic sulfoxides.October Revolution Fortieth Anniversary, Bashkir State University, UfaTranslated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1446–1447, June, 1990.