Abstract: An optical wavefront analyzer based on the phase-shearing interferometry technique for measuring a wavefront of a light beam is disclosed. The analyzer includes a single phase shifter, a driving device, a pattern receiving device, and a phase reconstructing device. A method of measuring a wavefront of a light beam is also provided for solving the problems of two-axial focusing and phase inconsistency encountered the prior art by employing phase-shearing and phase-shifting techniques to improve the method of optical wavefront mesurement. A non-iterative, path-independent unwrapping methodology is used to deal with a complicated wavefront.

Abstract: A novel trivalent Group IVB metal complex for preparing syndiotactic vinyl aromatic polymers is disclosed which is coordinated by a bidentate ligand and is represented by the formula (I):(C.sub.5 R.sub.n H.sub.5-n)M(BD).sub.m Y.sub.p (I)wherein C.sub.5 R.sub.n H.sub.5-n is a substituted or unsubstituted cyclopentadienyl group, n is an integer between 0 and 5, and R is C.sub.1 to C.sub.12 alkyl, aryl, substituted alkyl, or substituted aryl; M is a trivalent Group IVB metal; (BID) is a bidentate ligand with -1 valence, having a coordinating group which is capable of forming a coordinating bond or a chelating bond with the metal M; Y is selected from the group consisting of alkyl, aryl, aralkyl, halogen and hydrogen; m is an integer of 1 or 2; and m+p=2.

Abstract: A novel organometallic compound is disclosed which can be used, in conjunction with a trialkyl or bialkyl aluminum cocatalyst, for catalyzing the polymerization and copolymerization of ethylene without requiring the use of either methyl aluminoxane or borate as cocatalyst. The organometallic compound is represented by the formula of (CR.sub.5 R.sub.n H.sub.5-n)(L)MX.sub.a Y.sub.b ; wherein: (a) C.sub.5 R.sub.n H.sub.5-n is a substituted or unsubstituted cyclopentadienyl group, in which n is an integer between 0 and 5, and R is C.sub.1 to C.sub.6 alkyl group; (b) L is tetrapyrazolyl borate, hydrotrispyrazolyl borate, dihydrobispyrazolyl borate or hydrotris(3,5-dimethylpyrazolyl) borate; (c) M is a Group IIIB, Group IVB, or Group VB transitional metal; (d) a and b are integers such that a+b=m-2, where m is the valance of M; and (e) X and Y, which can be the same of different from each other, are halogen atoms or ligands represented by the formula of ER.sup.1, where E is a Group VA or VIA element, and R.sup.

Abstract: A novel trivalent Group IVB metal complex for preparing syndiotactic vinyl aromatic polymers is disclosed which is coordinated by a bidentate ligand and is represented by the formula (I):(C.sub.5 R.sub.n H.sub.5-n)M(BD).sub.m Y.sub.p (I)wherein C.sub.5 R.sub.n H.sub.5-n is a substituted or unsubstituted cyclopentadienyl group, n is an integer between 0 and 5, and R is C.sub.1 to C.sub.12 alkyl, aryl, substituted alkyl, or substituted aryl; M is a trivalent Group IVB metal; (BD) is a bidentate ligand with -1 valence, having a coordinating group which is capable of forming a coordinating bond or a chelating bond with the metal M; Y is selected from the group consisting of alkyl, aryl, aralkyl, halogen and hydrogen; m is an integer of 1 or 2; and m+p=2.

Abstract: A novel organometallic compound is disclosed which can be used, in conjunction with a trialkyl or bialkyl aluminum cocatalyst, for catalyzing the polymerization and copolymerization of ethylene without requiring the use of either methyl aluminoxane or borate as cocatalyst. The organometallic compound is represented by the formula of (C.sub.5 R.sub.n H.sub.5-n)(L)MX.sub.a Y.sub.b ; wherein: (a) C.sub.5 R.sub.n H.sub.5-n is a substituted or unsubstituted cyclopentadienyl group, in which n is an integer between 0 and 5, and R is C.sub.1 to C.sub.6 alkyl group; (b) L is tetrapyrazolyl borate, hydrotrispyrazolyl borate, dihydrobispyrazolyl borate or hydrotris(3,5-dimethylpyrazolyl) borate; (c) M is a Group IIIB, Group IVB, or Group VB transitional metal; (d) a and b are integers such that a+b=m-2, where m is the valance of M; and (e) X and Y, which can be the same of different from each other, are halogen atoms or ligands represented by the formula of ER.sup.1, where E is a Group VA or VIA element, and R.sup.

Abstract: A catalyst composition is disclosed for catalyzing the polymerization and copolymerization reactions of ethylene monomers, with or without another olefin monomer. The catalyst composition comprises a metallocene compound represented by the the formula of (C.sub.5 R.sub.n H.sub.5-n)(L)MXY or the formula of (C.sub.5 R.sub.n H.sub.5-n)(L)MX.sup.+ A.sup.- ; wherein: (a) C.sub.5 R.sub.n H.sub.5-n is a substituted or unsubstituted cyclopendadienyl group; (b) L is tetrapyrazolyl borate, hydrotrispyrazolyl borate, dihydrotrispyrazolyl borate or hydrotris-3,5-dimethyl; (c) M is Group IIIB, Group IVB, or Group VB transitional metal; (d) X is a C.sub.1 to C.sub.4 alkyl or alkenyl group, an aromatic group, an alkylaryl, a halogen, a hydrogen, or a silane group; (e) Y, which can the same as or different from X, is a C.sub.1 to C.sub.4 alkyl or alkenyl group, an aromatic group, an alkylaryl, a halogen, a hydrogen, or a silane group; and (f) A.sup.- is non-coordinated or loosely coordinated bulky anion. Examples of the (C.