PaperCrop is the best tool for your problem.
This tool was designed for two column research papers, cuts the columns and reformats it to one column.
It also has reflow for single column PDF which makes large PDF vewable on any smaller sized screen.
Here is the download page (
link)
And here is the MobiRead thread(
link)
This tool can pretty much make any PDF readable on the SONY. However the more complicated the PDF the more likely there will have to be some manual tailoring.
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