Top IPC subclasses
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1
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C02F
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16
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Treatment of water, waste water, sewage, or sludge
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2
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H01L
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3
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Semiconductor devices; electric solid state devices not otherwise provided for
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3
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C25B
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3
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Electrolytic or electrophoretic processes for the production of compounds or non- metals; apparatus therefor
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4
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H02M
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1
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apparatus for conversion between ac and ac, between ac and dc, or between dc and dc, and for use wit
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5
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F03G
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1
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spring, weight, inertia, or like motorsmechanical-power-producing devices or mechanisms, not otherwi
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