Abstract: A jig has a main body. The main body is provided with a rotatable engaging shaft. The engaging shaft is provided with a main body fixing portion actuator and a workpiece clamping portion actuator. The main body fixing portion actuator is provided with a main body fixing portion drivable by the main body fixing portion actuator. The workpiece clamping portion actuator is provided with a workpiece clamping portion drivable forward and backward by the workpiece clamping portion actuator. When the engaging shaft is rotated, attachment and detachment of the main body and clamping of a workpiece can be performed.

Abstract: According to this invention, there is provided an improved method of dyeing fibrous products characterized in that, in the dyeing of fibrous products using an oxidation-reduction dyeing type dye and an aqueous alkali solution of thiourea dioxide as a reducing solution, the reduction of the dye with the said aqueous alkali solution of thiourea dioxide is carried out in the presence of one or more substances selected from the group consisting of saturated aliphatic ketones having 3 to 10 carbon atoms, saturated aliphatic ketocarboxylic acids having 3 to 10 carbon atoms and alicyclic ketones having 3 to 10 carbon atoms.

Abstract: According to this invention, there is provided a method of dyeing fibrous products characterized in that, in the dyeing of fibrous products using an oxidation-reduction dyeing type dye and an aqueous alkali solution of thiourea dioxide as a reducing solution, the reduction of the dye with the said aqueous alkali solution of thiourea dioxide is carried out in the presence of one or more dialdehyde compounds selected from dialdehyde compounds represented by the general formulaOHC--R--CHO (I)in which R is a saturated or unsaturated aliphatic or aromatic organic compound radical.

Abstract: According to this invention, there is provided a method of stabilizing an alkaline aqueous solution of thiourea dioxide characterized in that one or more substances selected from the group consisting of aliphatic ketones, alicyclic ketones and aliphatic dialdehydes are added to the said alkaline aqueous solution of thiourea dioxide.

Abstract: According to the present invention, there is provided a process for preparing pyrazines characterized in that a diol represented by the formula ##STR1## wherein R.sub.1 and R.sub.2 are each a hydrogen atom or a hydrocarbon radical, and a diamine represented by the formula ##STR2## wherein R.sub.3 and R.sub.4 are each a hydrogen atom or a hydrocarbon radical, are subjected to a gas phase contact reaction in the presence of a zinc-containing catalyst.