1,721,530 research outputs found
The effect of workload and workshift on Air Traffic Control: A Taxonomy of Communicative Problems.
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Multidisciplinary approaches to resilience in tourism destination studies: a conceptual framework
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ZIEGLER-NATTA OLIGOMERIZATION OF 1-ALKENES - A CATALYST FINGERPRINT .1. HYDROOLIGOMERIZATION OF PROPENE IN THE PRESENCE OF A HIGHLY ISOSPECIFIC MGCL2-SUPPORTED CATALYST
No full textThe stereochemistry of propene polyinsertion catalyzed by a highly isospecific MgCl2-supported Ziegler-Natta system was investigated by means of the gas chromatographic/mass spectrometric (GC-MS) characterization of the saturated oligomers (hydrooligomers) formed in the presence of H2 at high pressure (as a chain transfer agent). It was shown that the hydrooligomer distribution is a true catalyst “fingerprint”, from which, in case of systems with (prevailingly) a single type of active centres, both the regio- and the stereospecificity of polyinsertion can be quantitatively evaluated
Mechanism of propagation and termination reactions in classical heterogeneous Ziegler-Natta catalytic system: A nonlocal density functional study.
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Do New Century Catalysts Unravel the Mechanism of Stereocontrol of Old Ziegler-Natta Catalysts?
No full textMOLECULAR MODELING OF STEREO- AND REGIOSELECTIVITY OF GROUP 4 HETEROCENES IN THE POLYMERIZATION OF PROPENE
No full textOrder-disorder phenomena in the crystalline polymorphic a and β forms of syndiotactic polystyrene
No full textModels of the chain packing for the ordered and disordered modifications of the α and β forms of syndiotactic polystyrene are suggested, through quantitative comparisons between X-ray diffraction intensities and calculated structure factors. The kinds of disorder present in both the crystalline forms are also discussed. In the α form the disorder corresponds to the statistical occurrence of two different, nearly isosteric, orientations of triplets of chains at well defined locations of a threedimensional lattice, while in the β form it corresponds to the statistical occurrence of two different kinds of stacking of ordered bilayers of macromolecules. © 1991 Accademia nazionale dei Lincei
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