Abstract: A catalyst for trimerization of ethylene is disclosed which comprises (a) a chromium complex having a neutral multidentate ligand having a tripod structure, represented by the formula, ACrJnQ3-n wherein A is a neutral multidentate ligand having a tripod structure, J is a carbonyl ligand or halogen, n is an integer of 0-3, and Q is at least one member selected from hydrogen, a C1-C10 hydrocarbon group, a C1-C10 carboxylate group, a C3-C10 diketonato group, an amide group, an imide group, an C1-C10 alkoxide group, a C1-C10 thioalkoxide group, an C6-C15 arene ligand, an C2-C10 alkene ligand, an C2-C15 alkyne ligand, an amine ligand, an imine ligand, an isonitrile ligand, a phosphine ligand, a phosphine oxide ligand, a phosphite ligand, an ether ligand, a sulfide ligand, a sulfone ligand and a sulfoxide ligand, and (b) a metal alkyl compound.

Abstract: An apparatus for controlling a rotational phase is disclosed. The apparatus comprises an input member provided so as to be rotatable, an output member co-axially provided with the input member so as to be rotatable, a planetary gear mechanism co-axially provided with the input member and the output member for connecting the input member with the output member, the planetary gear mechanism including three elements, namely a sun gear, a planetary carrier supporting planetary gears and a ring gear, a drive apparatus connected with one of the three elements of the planetary gear mechanism for shifting a rotation phase, the drive means including two members which are rotatable with respect to each other. One of the input member and the output member is connected with the ring gear, and the other of the input member and the output member is connected with the planetary carrier. The two members of the drive apparatus is co-axially provided with the planetary gear mechanism.

Abstract: A novel class of polyaryleneamines improved in physical and chemical properties, particularly in heat resistance and solvent resistance, and a process for producing the same are disclosed: said polymers having tertiary arylamino units bound in series.

Abstract: A combustion chamber for an engine is provided between a cylinder bore formed in a cylinder block, a generally conically-shaped wall formed in an under wall of a cylinder head, and a piston in the cylinder bore. The combustion chamber has a structure into which an intake port opens so as to introduce an intake air flow closer to a marginal portion than a central portion of the combustion chamber, thereby generating a swirl flow of intake air in the combustion chamber. The combustion chamber also includes a curved air flow guide wall formed in the generally conically-shaped wall which extends from near the intake port so as to approach the cylinder bore surface gradually, thereby generating what is termed a squish flow of intake air.