Abstract: A polymer containing a structural unit including an aromatic hydroxy group bonded to a main chain, where the aromatic hydroxy group is protected by an acid-labile group represented by the following formula (ALU-1) and is deprotected by action of an acid to become alkali-soluble. This provides: a polymer that makes it possible to form a resist film with which it is possible to form a pattern having extremely high isolated space resolution, small LER, and excellent rectangularity, effects of development loading and residue defects being suppressed, and the pattern having etching resistance and suppressed pattern collapse in the produced resist pattern; a chemically amplified positive resist composition containing the polymer; a resist patterning process using the chemically amplified positive resist composition; and a mask blank including the chemically amplified positive resist composition.

Abstract: A chemically amplified positive resist composition is provided comprising a polymer comprising units containing a phenolic hydroxy group and units containing a phenolic hydroxy group protected with an acid labile group, in which a carbon atom neighboring the carbon atom to which the phenolic hydroxy group protected with an acid labile group is attached is substituted with a specific group. A resist pattern with a high resolution, reduced LER, rectangularity, minimized influence of develop loading, and few development residue defects can be formed.

Abstract: A chemically amplified positive resist composition comprising (A) a base polymer, (B) a photoacid generator, and (C) a quencher is provided. The base polymer (A) contains a polymer comprising phenolic hydroxy group-containing units, aromatic ring-containing units, and units containing a phenolic hydroxy group protected with an acid labile group. The photoacid generator (B) and the quencher (C) are present in a weight ratio (B)/(C) of less than 3/1. The resist composition exhibits a very high isolated-space resolution and forms a pattern with reduced LER, rectangularity, minimized influences of develop loading and residue defects.

Abstract: A method for producting a solid acid catalyst is provided which produces a shaped material of a solid acid catalyst containing a sulfureous component but have a high activity and having a practically sufficient handleability and mechanical strength involves the steps of (a) fabricating a support containing a portion of zirconia and/or hydrated zirconia and a portion of alumina and/or hydrated alumina and having a peak diameter in the range of 0.05 to 1 &mgr;m in a pore diameter distribution of 0.05 to 10 &mgr;m; and having a sulfuerous component supported on the support or (b) fabricating a support containing a portion of zirconia and/or hydrated zirconia and a portion of alumina and/or hydrated alumina and including pores having a pore diameter of not less than 0.05 &mgr;m and not more than 1 &mgr;m occupying a pore volume of 0.05 to 0.5 ml/g and pores having a pore diameter of about 1 &mgr;m and not more than 10 &mgr;m occupying a pore volume of below 0.

Abstract: The present invention relates to a shaped solid acid catalyst for the isomerization of hydrocarbons and so on, which has a high activity and is excellent in strength and easily handleable, and processes for the preparation thereof. This catalyst comprises a support comprising portions of zirconia having a tetragonal form and portions of alumina, and a sulfureous component and, if necessary, a Group 8, 9 or 10 metal component both being supported on the support, and has a specific surface area of 150 m2/g or above. The catalyst can be prepared by kneading aluminum hydroxide, zirconium hydroxide and a sulfureous compound, shaping the kneaded mixture, calcining the shaped material at such a temperature as to form tetragonal zirconia and, if necessary, supporting a Group 8, 9 or 10 metal component on the calcined material and calcining the resulting molding at 300 to 700° C.

Abstract: The present invention relates to a shaped solid acid catalyst for the isomerization of hydrocarbons and so on, which has a high activity and is excellent in strength and easily handleable, and processes for the preparation thereof. This catalyst comprises a support comprising zirconia having a tetragonal form and alumina, and a sulfureous component and, if necessary, a Group 8, 9 or 10 metal component, both being supported on the support, and has a specific surface area of 150 m.sup.2 /g or above. The catalyst can be prepared by kneading aluminum hydroxide, zirconium hydroxide and a sulfureous compound, shaping the kneaded mixture, calcining the shaped material at such a temperature as to form tetragonal zirconia and, if necessary, supporting a Group 8, 9 or 10 metal component on the calcinedmaterial and calcining the resulting molding at 300 to 700.degree. C.

Abstract: A porous sintered material of good permeability and effective sound absorbability, being formed by combining between particles of aluminum or aluminum alloy powder into a body by means of sintering and having connecting pores among the particles of said aluminum or aluminum alloy powder. Said porous sintered material is obtained by mixing aluminum or an aluminum alloy with a low melting point aluminum alloy, forming the mixture into the predetermined shape and sintering it at a temperature which is at least 10.degree. C. lower than the melting point of the base material and higher than that of the low melting point material.

Abstract: Disclosed is a method for the recovery of useful metallic components such as lead, tin, copper, etc. from a closely layered member having its surface layer of copper or a copper or aluminum alloy closely layered on a back metal of steel or the like. The closely layered member is immersed in molten aluminum to dissolve therein the surface layer to separate it from the back metal, by which lead and/or tin is gathered under a molten aluminum or aluminum-copper layer and separated therefrom.