Measurements of mobilities and longitudinal diffusion coefficients of Na+ ions in Ne, Ar, and CH4 at room temperature by a continuous guard‐ring system

1983 ◽  
Vol 79 (8) ◽  
pp. 3893-3899 ◽  
Author(s):  
K. Iinuma ◽  
M. Takebe ◽  
Y. Satoh ◽  
K. Seto
Keyword(s):  
Diffusion Coefficients ◽  
Room Temperature ◽  
Ring System ◽  
Guard Ring ◽  
Longitudinal Diffusion ◽  
Na Ions

Mobilities and longitudinal diffusion coefficients for Na+ ions in Kr and Xe

1980 ◽  
Vol 73 (4) ◽  
pp. 2012-2013 ◽  
Author(s):  
M. G. Thackston ◽  
M. S. Sanchez ◽  
G. W. Neeley ◽  
W. M. Pope ◽  
F. L. Eisele ◽  
...  
Keyword(s):  
Diffusion Coefficients ◽  
Longitudinal Diffusion ◽  
Na Ions

Swelling pressure and microstructure of an activated swelling clay with temperature

Clay Minerals ◽  
1998 ◽  
Vol 33 (2) ◽  
pp. 255-267 ◽  
Author(s):  
D. Tessier ◽  
M. Dardaine ◽  
A. Beaumont ◽  
A. M. Jaunet
Keyword(s):  
Room Temperature ◽  
Swelling Pressure ◽  
Radioactive Waste Disposal ◽  
Basic Medium ◽  
Hydraulic Pressure ◽  
Swelling Behaviour ◽  
Transmission Electron ◽  
Ca Ions ◽  
Na Ions ◽  
Marked Drop

AbstractClay from Fourges has been selected by the Commissariat à l'Energie Atomique as a support in radioactive waste disposal studies. This material was activated by adding Na2CO3, then compacted at 60 MPa. Subsequently, its swelling behaviour was monitored at 90°C and 145°C for 330 days and at the end of this period the samples were examined by transmission electron microscopy (TEM). For this, they were embedded in a resin then sectioned with an ultramicrotome for mineralogical and chemical analyses. The initial material is essentially composed of kaolinite and smectite. Addition of Na2CO3 at room temperature induces a replacement of Ca ions by Na ions and the precipitation of finely divided carbonates on the surface of the constituents. At the end of 330 days at 90°C under a hydraulic pressure of 1 MPa, the initial particles combine and the material exerts a swelling pressure of 20 MPa. A complete reorganisation of the clay crystallites is observed without significant dissolution of the solid phases. After the same time at 145°C under a hydraulic pressure of 10 MPa, in a basic medium, the combined conditions are such that a high proportion of the clay is dissolved with formation of amorphous aluminosilicates correlated with a marked drop in the swelling pressure to 5 MPa. This work establishes the advantages of following the macroscopic properties in parallel with the microstructure variations for understanding the changes in the properties of clays.

scholarly journals The Influence of Mn2+on DNA structure in the presence of Na+ions: A Raman spectroscopic study

2006 ◽  
Vol 20 (5-6) ◽  
pp. 261-268 ◽  
Author(s):  
Cristina M. Muntean ◽  
Rolf Misselwitz ◽  
Heinz Welfle
Keyword(s):  
Conformational Changes ◽  
Room Temperature ◽  
Dna Structure ◽  
Dna Melting ◽  
Physiological Concentration ◽  
Raman Spectroscopic ◽  
Calf Thymus ◽  
Dna Backbone ◽  
Na Ions ◽  
Phosphate Groups

The influence of Mn2+ions on the structure of natural calf thymus DNA was studied by Raman spectroscopy. Measurements were done at room temperature and pH 6.2±0.2, in the presence of the physiological concentration of 150 mM Na+ions, and in the presence of Mn2+concentrations that varied between 0 and 600 mM. No condensation of DNA was observed at any of the Mn2+concentrations. At 5 mM Mn2+and 150 mM Na+no significant influence of Mn2+ions on the DNA structure can be observed. Compared with our previous results obtained at 10 mM Na+ions, binding of Mn2+ions to charged phosphate groups and to DNA bases is inhibited in the presence of 150 mM Na+ions. DNA backbone conformational changes were not observed in the whole concentration range of Mn2+ions as judging from the Raman spectra. No evidence for DNA melting was identified. A high Mn2+affinity for binding to guanine N7 and possibly, in a much lesser extent, to adenine have been found.

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