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Et informatikkperspektiv på norsk lovgivning om karakterklager i høyere utdanning
KD har i en nylig proposisjon foreslått endringer av klagesensurordningen, hvor det legges opp til at en modell med blind omsensur, som allerede har vært brukt ved en del læresteder, nå skal gjøres obligatorisk for alle læresteder. I denne artikkelen sammenlignes gammel og ny klagesensurordning med ordningene i en del andre land. Vi diskuterer ulike typer sensurfeil (med eksempel fra programmer...
متن کاملZiegler-Natta Catalysis: Structural Variations and Tacticity Control
Models for the likely active catalysts in homogeneous Ziegler-Natta systems have been studied using ab initio quantum chemical methods. We investigated the geometries of the isoelectronic model complexes, X2M-R where X = C1 or Cp = (q5-CsHs); where M = Sc and Ti+ (and also Ti); and where R = H, CH3, or SiH3. The general trend is that the M = Sc compounds strongly prefer a planar configuration, ...
متن کاملChromium(III) Based Ziegler-Natta Catalysts for Olefin Polymerization
Four chromium based oxo-trinuclear carboxylate complexes were prepared by reacting chromium(III) nitrate nonahydrate with acetic acid and substituted carboxylic acids. They were characterized using infrared spectroscopy (FT-IR). Chromium content of the complexes was determined by titrimetry method. The chromium(III) monochloroacetate complex, [Cr3O(ClCH2COO)6.3H2O]NO3.3H2O in combination with d...
متن کاملDesign of stereoselective Ziegler-Natta propene polymerization catalysts.
After five decades of largely serendipitous (albeit formidable) progress, catalyst design in Ziegler-Natta olefin polymerization, i.e., the rational implementation of new active species to target predetermined polyolefin architectures, has ultimately become a realistic ambition, thanks to a much deeper fundamental understanding and major advances in the tools of computational chemistry. In this...
متن کاملStructural Characterization of Electron Donors in Ziegler–Natta Catalysts
Ziegler-Natta catalysis is a very important industrial process for the production of polyolefins. However, the catalysts are not well-understood at the molecular level. Yet, atomic-scale structural information is of pivotal importance for rational catalyst development. We applied a solid-state NMR/density functional theory tandem approach to gain detailed insight into the interactions between t...
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ژورنال
عنوان ژورنال: Offset
سال: 1969
ISSN: 2204-3659,1445-9418
DOI: 10.15209/offset.v0i16.927