Rheological behavior of low molecular weight polystyrene composites containing monodisperse crosslinked polystyrene beads

1999 ◽  
Vol 20 (4) ◽  
pp. 534-542 ◽  
Author(s):  
M. Park ◽  
R. Salovey
Keyword(s):  
Molecular Weight ◽  
Rheological Behavior ◽  
Low Molecular Weight ◽  
Polystyrene Beads ◽  
Crosslinked Polystyrene

Liquid Chromatographic Separations Using Rubber as the Stationary Phase

1963 ◽  
Vol 36 (1) ◽  
pp. 310-312
Author(s):  
P. I. Brewer
Keyword(s):  
Molecular Weight ◽  
Stationary Phase ◽  
Mobile Phase ◽  
Chromatographic Method ◽  
Mineral Oil ◽  
Low Molecular Weight ◽  
Chromatographic Separations ◽  
Liquid Chromatographic Method ◽  
Crosslinked Polystyrene ◽  
Liquid Chromatographic

Abstract In a previous communication it was reported that certain polymers could be separated from mineral oil by a liquid chromatographic method. n-Heptane was used as the mobile phase and small pieces of thin vulcanized natural latex as the stationary phase. It has now been found that compounds of lower molecular weight can also be separated by this method. The use of rubber for the separation of compounds of low molecular weight was first described by Boldingh; he found it advantageous first to swell the rubber with a different solvent from that used as the mobile phase. The use of a crosslinked dextran (“Sephadex”) for separating compounds in aqueous solution has been described by Gelotte. Vaughan has mentioned the possibility of using crosslinked polystyrene beads for this purpose.

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

Low-molecular-weight heparin in the prevention and treatment of thromboembolic disorders

1998 ◽  
Vol 1 (5) ◽  
pp. 166-174 ◽  
Author(s):  
Evelyn R Hermes De Santis ◽  
Betsy S Laumeister ◽  
Vidhu Bansal ◽  
Vandana Kataria ◽  
Preeti Loomba ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Low Molecular Weight ◽  
Prevention And Treatment
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