| 摘要 |
The device comprises a cylindrical body (11) extended at its upper end by a crown ring (12) and at its lower end by a frustoconical segment (13), itself extended by a microtube (10) inserted into a rectangular tab (14) from the two faces of which it projects, and which is extended as far as the upper edge of the frustoconical segment (13), at which a first annular projection (15) is arranged around the cylindrical body (11), at a short distance above which a second annular projection (16) is arranged, the diameter of the said annular projections being substantially smaller than that of the crown ring (12) and being very slightly greater than the internal diameter of the standard test tubes in which the device (1) is intended to be placed, the crown ring (12) coming to bear with its lower edge on the upper edge (21) of the said standard test tubes. <IMAGE>
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