Abstract: The invention relates to a process for preparing caprolactam by admixture of cyclohexanone oxime to a reaction mixture comprising caprolactam and sulfuric acid using a mixing device, said mixing device comprising (i) a tube through which the reaction mixture can flow, and (ii) channels disposed around the tube, said channels opening into the tube, said process comprising: passing the reaction mixture through the tube, and feeding the cyclohexanone oxime into the reaction mixture through one or more of said channels, wherein Re>5000, Re being the Reynolds number as defined by ?·V·D/?, wherein ?=density (in kg/m3) of the reaction mixture that is fed to the tube V=velocity of the reaction mixture, V being defined as W/A, wherein W is the flow rate (in m3/s) of the reaction mixture that is fed into the tube and A is the cross section area of the tube (in m2) at the level where said channels open into the tube D=diameter of the tube at the level where said channels open into the tube (in m) ?=viscosity of th

Abstract: The present invention relates to a process for purifying an impure stream of caprolactam while recovering not only pure caprolactam but also medium-to-high pressure steam. Preferably, the stream of impure or crude caprolactam, which comprises at a minimum a substantial portion of water, is obtained from depolymerization of a polyamide-containing composition. The resulting purified caprolactam will have a purity greater than 90 weight percent and the recovered steam will have a temperature sufficiently high to provide a driving force for use with other equipment, for instance, heat exchange equipment.

Abstract: A process for cleaning the interior walls of a reaction chamber after a number of silicon wafers is etched inside the chamber. The cleaning process includes bombarding the interior walls of the chamber with a first type of plasma in a dry cleaning operation, and then bombarding the interior walls of the chamber with a second type of plasma containing the element hydrogen in a warm-up operation. No silicon wafers need to be placed inside the chamber when the dry cleaning operation or the warm-up operation is conducted.

Abstract: The present invention relates to a process for purifying an impure stream of caprolactam while recovering not only pure caprolactam but also medium-to-high pressure steam. Preferably, the stream of impure or crude caprolactam, which comprises at a minimum a substantial portion of water, is obtained from depolymerization of a polyamide-containing composition. The resulting purified caprolactam will have a purity greater than 90 weight percent and the recovered steam will have a temperature sufficiently high to provide a driving force for use with other equipment, for instance, heat exchange equipment.

Abstract: A process for cleaning the interior walls of a reaction chamber after a number of silicon wafers is etched inside the chamber. The cleaning process includes bombarding the interior walls of the chamber with a first type of plasma in a dry cleaning operation, and then bombarding the interior walls of the chamber with a second type of plasma containing the element hydrogen in a warm-up operation. No silicon wafers need to be placed inside the chamber when the dry cleaning operation or the warm-up operation is conducted.

Abstract: A waterless seasoning process is described, which waterless seasoning process is suitable for an etching chamber of an etching machine when the etching environment is so bad that etching cannot be performed. A dry cleaning process with a plasma formed by oxygen and hydrogen bromide is performed to restore the etching environment in the etching chamber.

Abstract: A chair assembly, which includes a plurality of supporting legs connected to a locating member and a ring to hold a stem socket by plugging, a stem inserted into the center through hole on the stem socket and retained at the desired elevation by a tapered packing ring, a cushion, and a mounting device inserted into a bottom hole on the cushion and secured to the cushion through a rotary joint and having a bottom end fitted into a hole on the stem for permitting the cushion to be supported on the stem.

Abstract: A multi-deck rack comprising a plurality of boards having two tapered holes at two opposite ends respectively attached with a taper ring each and mounted on two supporting posts at different levels, wherein downward pressure on the boards causes the boards to be firmly retained on the supporting posts in position; upwards pressure on the boards causes the boards to be moved upwards on the supporting posts for adjusting level positions.