What do A pos and C pos mean?
The # column is the rank of each listed entry for National Institute for Materials Science — rank 1 means this entry is where National Institute for Materials Science has the most articles or citations. A pos and C pos show the reciprocal: the position of National Institute for Materials Science within that entry's own ranked list, by articles and citations respectively. A low value means National Institute for Materials Science is among the most prominent contributors for that entry.