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2018
It is built from checkable properties of the record itself: whether the article has a DOI, how many independent sources confirmed its data, whether the required fields are filled in, and how recent the latest confirmation is. Disagreement between sources and a missing identifier lower it. A value of 80 or above means the record was published without further checking; 60 to 79 means it is published at reduced confidence, with a manual check advisable. A record verified by an editor by hand is never pushed below 90 by a recalculation. This scores our data about the article, not the article itself.
The results of an investigation dealing with pure ammonium perrhenate synthesis from crude ammonium perrhenate by multi-stage recrystallization are presented. It is shown that it is impossible to produce ammonium perrhenate of the AP-00 grade with the permissible potassium impurity level using this method. Recommendations for synthesis of the salt of the AP-0 grade are given.