Results 1 to 10 of about 39,823 (345)

Structural Characterization of Electron Donors in Ziegler–Natta Catalysts [PDF]

The Journal of Physical Chemistry C, 2018
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.
E. S. Blaakmeer, G. Antinucci, A. Correa, V. Busico, E. R. V. van Eck, A. Kentgens   +5 more
semanticscholar   +8 more sources

Accretion properties of T Tauri stars in sigma Ori [PDF]

, 2008
Accretion disks around young stars evolve in time with time scales of few million years. We present here a study of the accretion properties of a sample of 35 stars in the ~3 million year old star-forming region sigma Ori. Of these, 31 are objects with evidence of disks, based on their IR excess emission.
A. Natta, Barrado y Navascués, Bessell, Bessell, Bessell, Brown, Béjar, Béjar, Caballero, Caballero, Calvet, Calvet, Carpenter, Chiang, D'Alessio, D'Antona, Dahm, Dullemond, Edwards, Folha, Franciosini, G. Sacco, Hartmann, Hernández, Hillenbrand, Kenyon, Kenyon, L. Testi, Lada, Mohanty, Muzerolle, Muzerolle, Muzerolle, Natta, Natta, Oliveira, Oliveira, S. Randich, Sherry, Sicilia-Aguilar, Sicilia-Aguilar, Sicilia-Aguilar, Sicilia-Aguilar, Skrutskie, T. Gatti, Zapatero Osorio   +45 more
arxiv   +3 more sources

Preparation of High-Performance Polyethylene Nanocomposites with Oleic Acid–Siloxene-Supported Ziegler–Natta Catalysts [PDF]

Molecules
The addition of two-dimensional inorganic nanomaterials can effectively enhance the properties of polyethylene (PE). In the present study, a series of high-performance PE/oleic acid (OA)–siloxene nanocomposites were prepared by in situ polymerization ...
Huan Yue, Xin Yan, Chenghan Huang, Hexin Zhang, Jianming Yang, Liang Fang, Hee-Seon Kim   +6 more
doaj   +2 more sources

Preactive Site in Ziegler–Natta Catalysts [PDF]

The Journal of Physical Chemistry C, 2019
Ziegler–Natta catalysts are one of the most important industrial catalysts for the production of isotactic polypropylene, yet they are still not properly understood at the molecular level.
E. S. Blaakmeer, Frank J. Wensink, E. V. Eck, G. D. Wijs, A. Kentgens   +4 more
semanticscholar   +3 more sources

Exploring Brown Dwarf Disks [PDF]

, 2001
We discuss the spectral energy distribution of three very low mass objects in Chamaeleon I for which ground-based spectroscopy and photometry as well as ISO measurements in the mid-infrared are available (Comeron et al. 2000; Persi et al. 2000). One of these stars (Cha Halpha1) is a bona-fide brown dwarf, with mass 0.04-0.05 Msun.
A. Natta, Allard, Baraffe, Basri, Beckwith, Chiang, Chiang, Comerón, Comerón, Henning, Kenyon, L. Testi, Leggett, Lucas, Muzerolle, Natta, Natta, Neuhäuser, Oasa, Persi, Pickett, Reipurth, Waelkens, Zapatero Osorio   +23 more
arxiv   +4 more sources

First evidence for dusty disks around Herbig Be stars [PDF]

Astrophys.J.598:L39-L42,2003, 2003
We have carried out a high-sensitivity search for circumstellar disks around Herbig Be stars in the continuum at 1.4mm and 2.7mm using the IRAM interferometer at the Plateau de Bure (PdBI) . In this letter, we report data on three well studied B0 stars, MWC 1080, MWC 137 and R Mon. The two latter have also been observed in the continuum at 0.7 cm and 1.
A. Fuente, A. Natta, A. Rodrguez-Franco, Curiel S., Fuente A., Girart J. M., L. Testi, Leinert C., R. Bachiller, R. Neri, The P. S.   +10 more
arxiv   +3 more sources

The charge percolation mechanism and simulation of Ziegler-Natta polymerizations, part VI: Mechanism of ethylene polymerization by supported chromium oxide [PDF]

Journal of the Serbian Chemical Society, 2007
Despite intensive research over the last 50 years, many questions concerning ethylene polymerization by supported chromium oxide are still unanswered. Hence, the very fundamental issues of this polymerization are discussed in this paper. It is shown that
Stoiljković Dragoslav, Pilić Branka, Bulajić Miša, Đurasović Nebojša, Ostrovski Nikolaj   +4 more
doaj   +3 more sources

Flared Disks and Silicate Emission in Young Brown Dwarfs [PDF]

Astrophys.J. 609 (2004) L33-L36, 2004
We present mid-infrared photometry of three very young brown dwarfs located in the $\rho$ Ophiuchi star-forming region -- GY5, GY11 and GY310 --obtained with the Subaru 8-meter telescope. All three sources were detected at 8.6 and 11.7$\mu$m, confirming the presence of significant mid-infrared excess arising from optically thick dusty disks.
Antonella Natta, Comeron F., David Barrado y Navascués, D’Antona F., Motohide Tamura, Ray Jayawardhana, Subhanjoy Mohanty, Takuya Fujiyoshi   +7 more
arxiv   +3 more sources

Electronic Properties of Ti Sites in Ziegler–Natta Catalysts [PDF]

ACS Catalysis, 2021
A. Piovano, M. Signorile, L. Braglia, P. Torelli, Andrea Martini, Toru Wada, Gentoku Takasao, Toshiaki Taniike, E. Groppo   +8 more
semanticscholar   +2 more sources

Theoretical Study of the Halogen Concentration Effect on the 1,3-Butadiene Polymerization Catalyzed by the Neodymium-Based Ziegler–Natta System

Reactions
In this work, an attempt is made to theoretically substantiate the experimentally known facts of the influence of halogen concentration on the catalytic properties of the neodymium-based Ziegler–Natta system.
Alexey N. Masliy, Ildar G. Akhmetov, Andrey M. Kuznetsov, Ilsiya M. Davletbaeva   +3 more
doaj   +2 more sources