Abstract: An (S)-4-hydroxy-2-oxo-1-pyrrolidine acetamide racemate referred to as (S)-oxiracetam crystal form II has a diffraction peak at a diffraction angle 2? of 10.669, 13.25, 13.847, 14.198, 16.729, 17.934, 18.746, 18.816, 20.273, 20.413, 21.431, 21.617, 21.663, 23.38, 24.324, 24.415, 26.069, 26.107, 27.901, 28.621, 28.925, 29.449, 29.484, 31.702, 36.516, 37.685, or 39.721 degrees. The purity of the (S)-oxiracetam crystal form II can be up to 98.5%, and the (S)-oxiracetam crystal form II has the advantages of simple preparation method, mild control condition, low production cost, and the produced oxiracetam hydrate crystal form II has a high purity (the oxiracetam hydrate crystal form having a purity of 8%˜98.5% can be prepared by a crude levo-oxiracetam having a purity of 92%, and thus having a good reproducibility in production.

Abstract: Disclosed is a 4-hydroxy-2-oxo-1-pyrrolidineacetamide racemate crystal form I which is prepared by the following steps: dissolving crude 4-hydroxy-2-oxo-1-pyrrolidineacetamide racemate in a solvent such as a micromolecular alcohol to form a saturated solution; heating and stirring the solution overnight at 38˜42° C. to obtain a suspended precipitate; filtering and drying the solution to obtain a crystal. Such 4-hydroxy-2-oxo-1-pyrrolidineacetamide racemate crystal form I has a purity as high as 99.5%, which has significant treatment effect on curing respective diseases, and the 4-hydroxy-2-oxo-1-pyrrolidineacetamide racemate crystal form I has the features of simple manufacturing method, mild control condition, and low production cost, and its yield rate is as high as 99.5% which is applicable for mass production.

Abstract: A method for purifying (S)-oxiracetam is disclosed. Crude (S)-oxiracetam with the purity of 89% is dissolved in water; the solution is allowed to stand for 1 to 3 days at 0° C. to 18° C.; a colorless transparent crystal is precipitated; the solution is filtered and top-washed with cold water to 0° C. to 5° C.; and the product is dried in vacuum to obtain high-purity (S)-oxiracetam.

Abstract: A drill head locking apparatus and a drill head are provided. The locking apparatus includes a protruding platform having a through hole, a bearing on the inner wall of a small cylinder on the protruding platform, a locking sleeve fitted on the protruding platform, and a protrusion arranged on the upper part of the inner wall of the locking sleeve. The lower part of the inner wall of the locking sleeve is a conical face. A spring is arranged between the bottom face of the conical face and an upper bottom face of the protruding platform. A press plate is connected with a screw thread on the outer wall of the top part of the small cylinder on the protruding platform and presses down on the protrusion. A conical hole is arranged on the wall of the small cylinder and communicates with the through hole of the protruding platform.

Abstract: A craniotomy drill includes a main machine, a retarder and a locking seat. A drill transmission rod connected to the output shaft of the retarder is inserted in the locking seat. The main machine comprises a handle at the lower portion and an accommodating part at the upper portion, with a stator and a rotor of a DC electric motor being provided inside the accommodating part and a wall of the accommodating part being the stator housing of the DC electric motor. This craniotomy drill has a simple structure with the wall of the accommodating part as the stator housing of the electric motor, such that the volume and the weight are reduced. It is safe in use without the risk of the electric motor sliding out. By utilizing materials and processes of water resistant technology and an integrative design, a relatively good water resistant performance is achieved.

Abstract: A surgical milling cutter bracket includes a retaining base having a through hole. The upper part of the retaining base is provided with a finger guide having an L-shaped support frame on the top of the finger guide. A downward protrusion is provided at the end of the short side of the L-shaped support frame. The lowest point of the protrusion is lower than the lowest point of the cylindrical head of the milling cutter during normal operation of the milling cutter. A bolt having a through hole at the center is fixed within the cavity of the finger guide. A depressor is provided on the upper part of the retaining base. The bolt passes through a hole of the depressor and is connected to a nut. The protrusion is able to prevent an object from contacting the cylindrical head, thus avoiding cutting the object unevenly.

Abstract: A drill bit locking device and a drill bit are provided. The locking device includes a boss with a through hole, a bearing and a support member are arranged an inner wall of a small cylinder above the boss; a locking sleeve is sleeved over the boss, a first bulge is on an inner wall of an upper part of the locking sleeve, and a second bulge is on an inner wall of a lower part; a spring is between the second bulge and an upper bottom surface of the boss; a press plate is threadedly connected with an outer wall of a top part of the small cylinder and presses against the first bulge; holes of different sizes are on the inner wall of the small cylinder and the support member to form a stepped hole, and a steel ball is arranged in the stepped hole.