unitpackage.database.echemdb_entry

A Data Package describing an entry in the echemdb database. It provides additional functionalities compared to the class Entry.

These are the individual elements of a Echemdb.

EXAMPLES:

We can directly access the material of an electrode used in the experiment, such as the working electrode (WE), counter electrode (CE) or reference electrode (REF):

>>> from unitpackage.database.echemdb import Echemdb
>>> db = Echemdb.create_example()
>>> entry = db['alves_2011_electrochemistry_6010_f1a_solid']
>>> entry.get_electrode('WE').material
'Ru'

The plot() creates a typical representation of a CV, where I or. j is plotted vs. U or. E:

>>> entry.plot()
Figure(...)

class unitpackage.database.echemdb_entry.EchemdbEntry(resource)

A frictionless Data Package describing a CV.

EXAMPLES:

Entries are normally obtained by opening a Echemdb of entries:

>>> from unitpackage.database.echemdb import Echemdb
>>> collection = Echemdb.create_example()
>>> entry = next(iter(collection))

get_electrode(name)

Returns an electrode with the specified name.

EXAMPLES:

>>> entry = EchemdbEntry.create_examples()[0]
>>> entry.get_electrode('WE')
{'name': 'WE', 'function': 'workingElectrode', 'type': 'single crystal',
'crystallographicOrientation': '0001', 'material': 'Ru',
'preparationProcedure': 'Sputtering and flash annealing under UHV
conditions with repeated cycles of oxygen adsorption and desorption.',
'shape': {'height': {'unit': 'mm', 'value': 2}, 'type': 'hat shaped'},
'source': {'supplier': 'Mateck'}}

TESTS:

>>> entry.get_electrode('foo')
Traceback (most recent call last):
...
KeyError: "Electrode with name 'foo' does not exist"

plot(x_label='E', y_label='j', name=None)

Return a plot of this entry. The default plot is a Cyclic Voltammogram (‘j vs E’). When j is not present in the data, I is used instead.

EXAMPLES:

>>> entry = EchemdbEntry.create_examples()[0]
>>> entry.plot()
Figure(...)

The plot can also be returned with custom axis dimensions (field names) available in the resource:

>>> entry.plot(x_label='t', y_label='E')
Figure(...)

A plot resembling the original figure can be obtained by first rescaling:

>>> rescaled_entry = entry.rescale('original')
>>> rescaled_entry.plot()
Figure(...)

rescale(units)

Return a rescaled EchemdbEntry with axes in the specified units.

Usage is essentially the same as for rescale(), i.e., new units are expected as dict, where the key is the axis name and the value the new unit, such as {'j': 'uA / cm2', 't': 'h'}.

Additionally, the entry can be rescaled to the axes’ units of the original data. These units must be defined in the metadata of the resource, within the key figureDescription.fields:

>>> entry = EchemdbEntry.create_examples()[0]
>>> rescaled_entry = entry.rescale(units='original')
>>> rescaled_entry.mutable_resource.schema.fields
[{'name': 't', 'type': 'number', 'unit': 's'},
{'name': 'E', 'type': 'number', 'unit': 'V', 'reference': 'RHE'},
{'name': 'j', 'type': 'number', 'unit': 'mA / cm2'}]

thumbnail(width=96, height=72, dpi=72, **kwds)

Return a thumbnail of the entry’s curve as a PNG byte stream.

EXAMPLES:

>>> entry = EchemdbEntry.create_examples()[0]
>>> entry.thumbnail()
b'\x89PNG...'

The PNG’s width and height can be specified in pixels. Additional keyword arguments are passed to the data frame plotting method:

>>> entry.thumbnail(width=4, height=2, color='red', linewidth=2)
b"\x89PNG..."