Accès ouvert
2026
article
OpenAlex
Indrek Kivi, S. Paydar, J Aruväli, O. Volobujeva et autres
This paper presents the study of the influence of B-site doping (Ni/Cu ratio in the B-site) and A-site deficiency on the microstructural, electrical and electrochemical properties of (La 0.25 Sr 0.25 Ca 0.45 ) y Ti 0.95 Ni 0.05-x Cu x O …
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Accès ouvert
2001
article
OpenAlex
A Loog, T Kurvits, J Aruväli, V Petersell
The Tremadocian black shale or so-called Dictyonema shale of Estonia con- sists of 65--70 % mostly silicate minerals, 10-15 % organic and 10-20 % X- ray amorphous matter.Grain size and the quantitative analysis of silicate minerals in black shale was carried out.After …
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Accès ouvert
1996
article
OpenAlex
A Loog, J Aruväli, V Petersell
Tremadocian Dictyonema shale (argillite) is black argillaceous rock containing 10-20 % organic matter, abundant in sulfur and numerous microelements.Dictyonema shale is characterized by a high potassium and a low sodium content.
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Accès ouvert
1995
article
OpenAlex
A Loog, J Aruväli, V Petersell
In the present paper the morphological description, mineralogical and chemical composition of diagenetic carbonate formations occurring in low-grade oil shale, known as Tremadocian graptolitic argillite or Dictyonema shale, is given.The role of these formations in the redistribution of several microelements during diagenesis …
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