Inkscape

Change lines thickness of eps converted PDF

Start by

inkscape

Or Right click pdf file, Open With -> Other Application -> Use a custom command -> inkscape
Select OK for the PDF import settings

Resize canvas to image

Shift+Ctrl+d (File->Document properties).

Inkscape version 0.47: Alt+f (Fit page to selection)
Inkscape version 0.48: Alt+z, Alt+r (Resize page to content -> Resize page to drawing or selection)

Line size change - fill and stroke

With the Black arrow tool, Click on a Top in the spectrum, which will expand a selection box for the whole 1H,N15 area.
Shift+Ctrl+F (Object->Fill and stroke), Stroke style, set Width 1.000 px, enter

Modify a text or a label object

With the Black arrow tool, double Click on a Label in the spectrum, which will expand a selection box.
You can switch between "rotation mode" or "Stretch mode" by clicking once one the object, with With the Black arrow tool.

Saving

As pdf

File -> Save as: test2.pdf

As png

This way sets the background "Transparent"

File -> Export bitmap -> Page
Set 200 dpi

Rotate object - Transform

Shift+Ctrl+m (Object->Transform)