Untersuchung der Fette

Ohne Zusammenfassung     

Time-temperature superposition and relaxational behavior in polymeric glasses

It is shown that a free-volume treatment of the relaxational behavior of a polymer can be extended into the glassy region. A modified form of the WLF equation is derived in which the temperature is replaced by T_e, a parameter related to the “frozen” free volume in the glass and defined such that Te = T at equilibrium. Measurements of the isothermal volume contraction of polystyrene and poly(methyl methacrylate) between ?20 and + 95°C are used to estimate the “frozen” free volume and to calculate the temperature dependence of log(a_T) below Tg. The calculated shift factors are compared to experimental values for the glassy state, and good agreement is obtained by selecting an arbitrary, but reasonable, equilibrium glass volume-temperature curve. The slope of this equilibrium glass curve is smaller than the experimental volume curve at some finite cooling rate. The data indicate that the glass is not an “iso-free volume” state and that the relaxation mechanisms in the glass are controlled primarily by the free volume, at least in the vicinity of Tg. A quantitative definition of the role of free volume in the glassy state requires evaluation of the quantities ? log a_T/?V)_T,P and (? log a_T/?T)_v,p; sufficient data of this type are not presently available.     

Anwendung von Faserlichtleitern zur Kombination eines einfachen Titrierger?tes mit Photometern

Zusammenfassung Gebündelte Faserlichtleiter ermöglichen den Anschlu\ von Titriervorrichtungen an moderne Photometer. Der Bau einer einfachen Titriervorrichtung wird beschrieben und diverse Anschlu\varianten werden skizziert. Methodische Beispiele erlÄutern einige typische Einsatzmöglichkeiten der Kombination Photometer-Lichtleiter-Titriervorrichtung.

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Connection of a simple titrating apparatus with spectrophotometers by application of fibre optic light guides

Summary Fibre optic light guides provide the possibility for connecting a titrating apparatus with up-todate spectrophotometers. A methodical instruction to build a simple titrating apparatus is given and some variants of connection are described. A few typical applications of the combination spectrophotometer — light guides — titrating apparatus are illustrated by methodical examples.

Methoden und Umrüstung wurden an einem Spektrophotometer des Typs Pye Unicam SP6-300 erprobt.Als Faserlichtleiter gelangten mit Glasseide/Silicon ummantelte Glasfaserleiter Fibroflex (Rank Precision) zum Einsatz.     

Chemical effects on oscillatory cross sections in low energy ion scattering

Oscillatory structure in the scattered ion yield for He⁺ scattering from In has been observed to depend upon the chemical environmental of the In. Fourier analysis of the oscillatory structure indicates two major components whose relative amplitudes vary significantly with chemical environment.     

Second order theory of excitations in trapped bose condensates at finite temperatures

We present a finite temperature field theory for collective excitations of trapped Bose condensates which includes the dynamics of the thermal cloud. In spherical traps we show that excitations couple strongly to a small number of modes, giving resonance structure in their frequency spectra. Where possible, we derive energy shifts and lifetimes of excitations. For the l = 0 mode we show that the simple picture of a decay rate fails, which should be observable in suitable experiments. It also suggests a possible explanation for the anomalous behavior of the m = 0 mode observed in anisotropic traps.     

Suppression of Output Power and NF Excursions in Cascades of Highly Inverted EDFAs with Packet-Switched Traffic

Significant output power excursions in cascades of erbium-doped fiber amplifiers (EDFAs) can cause serious problems in wavelength division multilexing (WDM) packet-switched burst-mode networks. Signal power excursions more serious than those induced by channel addition/removal in circuit switched networks can arise when data on the WDM channels is highly variable in nature. Self-similar traffic can be subject to large variation in EDFA gain. In order to prevent unacceptable error bursts, due, for example, to channel power becoming too low to preserve adequate eye opening or exceeding thresholds for optical nonlinearities, the channel power should be maintained constant. In this letter, it is shown that the sizable power and noise figure swings arising in a cascade of EDFAs with WDM burst-mode packet-switched networks with self-similar traffic can be effectively suppressed when highly inverted amplifiers are employed. The analysis is based on the application of a numerical model, which solves the transcendental equation for length averaged metastable level population of an EDFA.     

New designs and structure activity relationships in antitumoral aziridinyl cyclophospha(thia)zenes

Abstract

The partial aziridinolysis of (NPCl₂)_3,4 and (NPCl₂)₂ NSOCl yields non-geminal and geminal chloro-aziridinyl derivatives. Compounds N₃P₃Az_6-nR_n (R[dbnd]amino, alkoxy, aryloxy, id.) show in vitro and in vivo cytostatic activity. Structure-activity relationships are proposed. Phase I clinical trials of (NPAz₂)₂ NSOAz (Az[dbnd]1-aziridinyl) are summarized.     

High energy heavy ion interactions studied with SSNTDs

We have continued our studies of heavy ion projectile fragmentation using nuclear track detectors. Based on automatic track measurement it was possible to perform experiments with high statistical significance. Beams of different ions from the Berkeley BEVALAC, the Dubna Synchrophasotron, the Brookhaven AGS and the GSI Darmstadt SIS have been used. With CR-39 and BP-1 glass detectors we have studied the process of electromagnetic dissociation, we investigated multifragmentation and continued the search for quark nuclear complexes. This paper gives an overview of these experiments. Details of the experimental technique are discussed.