The simple answer to your question is: Yes.

The larger question is whether you want to continue as a private non-operating foundation or whether you want to try to be a private operating foundation or a public charity.  As the publisher of an online educational journal, you might be able to qualify as a private operating foundation.  You would have to spend the bulk of your money for direct activity in your field and avoid too much traditional grant activity.  The principal benefits of a private operating foundation come from having to spend less of your investment income each year than a private foundation and being able to give donors the greater deductibility that would come from gifts to public charities.  (See Ready Reference Page:  “Private Operating Foundations are Hybrids”)

Depending on your dividend and interest income from investments, however, you may have enough revenue from the subscriptions to qualify as a public charity.  If you advise the IRS of your intent to switch, you would have a five-year period over which you would have to prove your public support.  Subscription revenue could be enough to provide you required percentage, however.  You would be more attractive to donors (including other private foundations) and would not be prohibited from lobbying for legislative changes in your area of interest.  You would also be able to engage in a more significant grant program if you have the funds to do so.  (See Ready Reference Page: “Terminating Private Foundations May Be Tricky”)

There may be other issues in how you acquire responsibility for this journal, particularly if it has been operated by a disqualified person with respect to the foundation.  But those are beyond the scope of your question.