Abstract: There is provided a porous honeycomb filter. When gas is supplied to the inlet side flow channels from the inlet side end face, the filter satisfies Expression (1), where at each position in a surface of an inner wall of the inlet side flow channel, a gas flow rate in a direction perpendicular to the surface is V, an average of V is VAV, a value of V/VAV at a position with a cumulative frequency of 10% when a distribution of V/VAV is arranged in ascending order is VV10, and a value of V/VAV at a position with a cumulative frequency of 90% when the distribution of V/VAV is arranged in ascending order is VV90, VV90?VV10?0.4 ??(1).

Abstract: A honeycomb filter comprises a columnar body including inlet-side flow passages (first flow passages) and outlet-side flow passages (second flow passages) extending in an axial direction and including partition walls W separating the adjacent flow passages. A cross-section area of each inlet-side flow passage on one end face of the columnar body is larger than a cross-section area of each inlet-side flow passage in a central part in the axial direction, and a cross-section area of each outlet-side flow passage is closed on the one end face. A corner part C that forms the inlet-side flow passage and is formed between an adjacent pair of partition walls W has a protrusion part (first protrusion part)—that protrudes toward an interior of the inlet-side flow passage and extends in the axial direction, in a central part of at least one of the inlet-side flow passages in the axial direction.

Abstract: A particulate filter 200 comprises: a columnar ceramic honeycomb structure 220 having a plurality of first channels 210a and a plurality of second channels 210b; and a catalyst component carried by the ceramic honeycomb structure 220. The catalyst component contains noble metal particulates, and the following expression is satisfied: 2 m2/L?SPout?SPcent?125 m2/L, where SPcent represents the total surface area of the noble metal particulates contained in an apparent unit volume of a central portion 220c of the ceramic honeycomb structure 220, and SPout represents the total surface area of the noble metal particulates contained in the apparent unit volume of a peripheral portion 220p of the ceramic honeycomb structure 220.

Abstract: The method for producing a fired body of the invention has the steps of: preparing a starting material mixture; molding the mixture to obtain a green molded body; a first heating step to make the molded body contain residual carbon-containing substances in a furnace by increasing the temperature of the furnace while introducing an oxygen containing gas; and a second heating step to obtain a fired body by further increasing the temperature of the furnace without introducing the oxygen containing gas; wherein the conditions for the first heating step are set so that when the molded body is allowed to stand after the first heating step in an oxygen-containing atmosphere at 900° C., the temperature at the center section of the molded body is at least 20° C. higher than the temperature of the atmosphere in the furnace.

Abstract: The present invention provides a green molded body capable of easily controlling the porosity of a honeycomb structure. One aspect of the present invention is a green molded body composed of a honeycomb-shaped cylindrical body 70 with a plurality of through holes 70a being formed approximately in parallel with each other, wherein the cylindrical body 70 comprises a ceramic raw material powder and a fluorine source, and wherein the ceramic raw material powder is the one for forming at least one of an aluminum titanate-based ceramics and a cordierite-based ceramics by sintering.

Abstract: The method for producing a fired body of the invention has the steps of: preparing a starting material mixture; molding the mixture to obtain a green molded body; a first heating step to make the molded body contain residual carbon-containing substances in a furnace by increasing the temperature of the furnace while introducing an oxygen containing gas; and a second heating step to obtain a fired body by further increasing the temperature of the furnace without introducing the oxygen containing gas; wherein the conditions for the first heating step are set so that when the molded body is allowed to stand after the first heating step in an oxygen-containing atmosphere at 900° C., the temperature at the center section of the molded body is at least 20° C. higher than the temperature of the atmosphere in the furnace.

Abstract: The invention is to provide a process for producing an aluminum titanate-based ceramic such as aluminum titanate or aluminum magnesium titanate having excellent thermal decomposition resistance and having a smaller coefficient of thermal expansion. The invention is a process for producing an aluminum titanate-based ceramic, comprising firing a starting material mixture containing a titanium source compound, an aluminum source compound and preferably a magnesium source compound, and a glass frit having a deformation point of 700° C. or more and/or a viscosity at 900° C. of 1.0×106 poises or more.

Abstract: An object of the present invention is to provide a molding and a method for producing the same; a catalyst for the production of an unsaturated aldehyde and an unsaturated carboxylic acid, and a method for producing the same; and a catalyst for the production of methacrylic acid, and a method for producing the same. The molding of the present invention shows a shape including a plurality of columnar portions disposed with a predetermined gap; and bridge portions which are provided at both ends in longitudinal directions of two adjacent columnar portions and join adjacent columnar portions each other; and including through holes surrounded by a plurality of columnar portions in the longitudinal directions of the columnar portions, and openings formed on a peripheral surface by a gap between the plurality of adjacent columnar portions.

Abstract: There is provided a formed article characterized in that it includes a cylindrical coil member having spiral turns with a predetermined pitch thereof and a supporting member which extends along a direction parallel to an axis of the cylindrical coil member and which connects the spiral turns, and also provided a production process of the formed article characterized in that an extruder is used which includes a first die having a groove on its outer peripheral surface and a second die in the form of a ring which has a groove on its inner peripheral surface and into which the first die is fitted, and a forming material is extruded by the extruder while only one of the dies is rotated with respect to the other die.

Abstract: A high-strength ?-alumina formed body with a low soda content, of which pore distribution is controlled, can be provided in an easy and inexpensive manner. The ?-alumina formed body can be produced by a method comprising calcining a gibbsite-phase aluminum hydroxide to obtain rehydratable alumina powder; forming the rehydratable alumina powder in the presence of water to obtain a formed body; maintaining the formed body in the presence of water at about 110-200° C., to rehydrate the formed body; and calcining the rehydrated formed body at about 1200° C. or higher. The ?-alumina formed body is useful as a carrier for catalysts, chemicals, microbes for food leftover disposal and the like.

Abstract: A spherical porous ceramic body and the production method thereof are provided. As to the porous ceramic body, the total volume of the pores having a pore radius of from 1.8 nm to 100 ?m is about 0.25 cm3/g or more, the mode of pore radius of the pores is from about 1 ?m to about 6 ?m and the packing density is from about 0.7 g/cm3 to about 1 g/cm3. The porous ceramic body is suitably used as a carrier for a catalyst and has high mechanical strength.

Abstract: An activated alumina formed body with a high bulk density and a large macro-pore volume is provided. The activated alumina formed body can be produced by a method comprising the steps of calcining a gibbsite-phase aluminum hydroxide having a median particle size of from about 10 ?m to about 35 ?m and a packed bulk density of from about 1.05 g/cm3 to about 1.3 g/cm3 to obtain an at least partially rehydratable alumina powder; forming the rehydratable alumina powder in the presence of water; maintaining the formed body in the presence of water to rehydrate the formed body; and calcining the rehydrated formed body to obtain an activated alumina formed body. The activated alumina formed body is usable as an adsorbent, a catalyst supporting precious metal or the like.

Abstract: An activated alumina formed body with a high bulk density and a large macro-pore volume is provided. The activated alumina formed body can be produced by a method comprising the steps of calcining a gibbsite-phase aluminum hydroxide having a median particle size of from about 10 ?m to about 35 ?m and a packed bulk density of from about 1.05 g/cm3 to about 1.3 g/cm3 to obtain an at least partially rehydratable alumina powder; forming the rehydratable alumina powder in the presence of water; maintaining the formed body in the presence of water to rehydrate the formed body; and calcining the rehydrated formed body to obtain an activated alumina formed body. The activated alumina formed body is usable as an adsorbent, a catalyst supporting precious metal or the like.

Abstract: A high-strength ?-alumina formed body with a low soda content, of which pore distribution is controlled, can be provided in an easy and inexpensive manner. The ?-alumina formed body can be produced by a method comprising calcining a gibbsite-phase aluminum hydroxide to obtain rehydratable alumina powder; forming the rehydratable alumina powder in the presence of water to obtain a formed body; maintaining the formed body in the presence of water at about 110-200° C., to rehydrate the formed body; and calcining the rehydrated formed body at about 1200° C. or higher. The ?-alumina formed body is useful as a carrier for catalysts, chemicals, microbes for food leftover disposal and the like.

Abstract: A high-strength &agr;-alumina formed body with a low soda content, of which pore distribution is controlled, can be provided in an easy and inexpensive manner. The &agr;-alumina formed body can be produced by a method comprising calcining a gibbsite-phase aluminum hydroxide to obtain rehydratable alumina powder; forming the rehydratable alumina powder in the presence of water to obtain a formed body; maintaining the formed body in the presence of water at about 110-200 ° C., to rehydrate the formed body; and calcining the rehydrated formed body at about 1200° C. or higher. The &agr;-alumina formed body is useful as a carrier for catalysts, chemicals, microbes for food leftover disposal and the like.

Abstract: An activated alumina formed body with a high bulk density and a large macro-pore volume is provided. The activated alumina formed body can be produced by a method comprising the steps of calcining a gibbsite-phase aluminum hydroxide having a median particle size of from about 10 &mgr;m to about 35 &mgr;m and a packed bulk density of from about 1.05 g/cm3 to about 1.3 g/cm3 to obtain an at least partially rehydratable alumina powder; forming the rehydratable alumina powder in the presence of water; maintaining the formed body in the presence of water to rehydrate the formed body; and calcining the rehydrated formed body to obtain an activated alumina formed body. The activated alumina formed body is usable as an adsorbent, a catalyst supporting precious metal or the like.

Abstract: A spherical porous ceramic body and the production method thereof are provided. As to the porous ceramic body, the total volume of the pores having a pore radius of from 1.8 nm to 100 &mgr;m is about 0.25 cm3/g or more, the mode of pore radius of the pores is from about 1 &mgr;m to about 6 &mgr;m and the packing density is from about 0.7 g/cm3 to about 1 g/cm3. The porous ceramic body is suitably used as a carrier for a catalyst and has high mechanical strength.

Abstract: There is provided a process for the production of a transition alumina by thermally decomposing an aluminum sulfate wherein the thermal decomposition is carried out under an atmosphere comprising a reducing substance, and the transition alumina produced by the process has a specific BET surface are of not smaller than 400 m.sup.2 /g.

Abstract: A heat resistant transition alumina produced by mixing aluminum sulfate and a lanthanum compound, heating the mixture, and then thermally decomposing the mixture, and a process for producing the heat resistant transition alumina. The heat resistant transition alumina has a high BET specific surface area, and an excellent heat resistance as exhibiting a less reduction in the BET specific surface area even under temperatures of 1000.degree. C. or higher, and exhibits a high porosity even when coated onto other catalyst supports having a lower specific surface area, and is producibile at a lower cost.