“…[1][2][3][4][5][6][7] Furthermore, application to thermodynamic studies or gas sensors by Na þ -0 -or 00 -alumina have also been made by many authors. [8][9][10][11][12][13][14][15][16][17][18][19][20] On the otherhand, in addition to ion-exchange research, there are some thermochemical researches involving the ionexchanged -or 00 -alumina. The following studies have been reported: measurements of Ag activity in solid Ag-Pd alloys using Ag þ -00 -alumina, 21) Ag activity in solid Ag-Au alloys 22) using Ag þ --alumina and Cu activity in liquid Cu-Sn alloys using Cu þ --alumina, 23) developments of SO x sensor using Ag þ --alumina 24,25) and NO x sensor using Ag þ --alumina, 26) determinations of 27) thermodynamic studies of sulfides using (Pb þ -Na þ )--alumina, 28) and so on.…”