A honeycomb structure includes: a honeycomb structure body; and a convex part that protrudes outward from a part of circumference of the honeycomb structure body. The convex part surrounds the circumference of the honeycomb structure body like a ring. The convex part is of a tapered shape at least at one end having a tapered face. The convex part has a circumference coating layer making up the tapered face. The convex part has a maximum thickness of 1 to 20 mm, and a rough-face region on the tapered face, the rough-face region having surface roughness of 5 to 70 m. The rough-face region has a total of a rough-face region angle of 108 or more. An inclination angle formed between the tapered face and the extending direction of the cells is 10 to 80 degrees.

A method of making SiC nanowires comprising: (a) mixing silicon powder with a carbon-containing biopolymer and a catalyst at room temperature to form a mixture; and (b) heating said mixture to a pyrolyzing temperature sufficient to react said biopolymer and said silicon power to form SiC nanowires.

A plugged honeycomb structure in which in a cross section of a honeycomb structure body which is perpendicular to an extending direction of cells, inflow cells are disposed to surround an outflow cell, and the number of the inflow cells is larger than the number of the outflow cells, and the cross section has a plurality of intersecting portions of partition walls each defining the inflow cells which are adjacent to each other, and in 60% or more of a total number of the intersecting portions, a relation between a diameter (D.sub.1) of a circle inscribed in the intersecting portion and a diameter (D.sub.0) of a circle inscribed in the partition wall defining the inflow cell and the outflow cell which are adjacent to each other satisfies D.sub.1/(2D.sub.0)=1.20 to 1.80

The invention relates to a wall-flow filter as a particle filter with catalytically active coatings in the channels which are closed in a gas-tight manner at the opposing closed ends of the channels A at the first end, wherein the inlet region of the filter is additionally supplied with a dry powder-gas aerosol which contains metal compounds with a high melting point (such as the metal oxides Al2O3, SiO2, FeO2, TiO2, ZnO2, etc. for example) and which is to simultaneously improve the catalytic activity and the degree of filtration efficiency with respect to the exhaust gas back-pressure.

A fine-particle number detector includes a filter selectively removing, from among fine particles in car exhaust gas introduced into a gas passage pipe, ultrafine particles not larger than a predetermined particle size that is previously set as an upper limit within a range of 25 nm or less, a charge adding device adding charges to the fine particles in the exhaust gas having passed through the filter, and producing charged fine particles and a detection device detecting the number of fine particles in the exhaust gas having passed through the filter on the basis of an amount of charges of the charged fine particles or an amount of charges having not been added to the fine particles.

A honeycomb structure having a hexagonal cross-sectional shape of cells and having specific open cells in which open changing portions are present only in a range of 30 mm or less from the first end face, and the open changing portion satisfies relations of 1|(1(D1/D2))100|70 and 1|(1(D3/D2))100|70. D1 indicates a diameter of an inscribed circle which comes in contact with a peripheral edge of the open end of the cell in the first end face. D2 indicates a diameter of the inscribed circle which comes in contact with the peripheral edge of the open end of the cell in the second end face. D3 indicates a diameter of an inscribed circle which comes in contact with a peripheral edge of the cell in a cross section perpendicular to a direction from the first end face toward the second end face.

A honeycomb structure having a quadrangular or triangular cross-sectional shape of cells and having specific open cells in which open changing portions are present only in a range of 20 mm or less from the first end face, and the open changing portion satisfies relations of 1|(1(D1/D2))100|80 and 1|(1(D3/D2))100|80. D1 indicates a diameter of an inscribed circle which comes in contact with a peripheral edge of the open end of the cell in the first end face. D2 indicates a diameter of the inscribed circle which comes in contact with the peripheral edge of the open end of the cell in the second end face. D3 indicates a diameter of an inscribed circle which comes in contact with a peripheral edge of the cell in a cross section perpendicular to a direction from the first end face toward the second end face.

In the plugged honeycomb structure, 30% or more of first intersection portions in which a first partition wall intersects a second partition wall are first specific intersection portions in which a diameter of a maximum inscribed circle drawn in the first intersection portion is a specific size for a shortest distance between an inflow cell and an outflow cell, and 30% or more of non-first intersection portions other than the first intersection portions are non-first specific intersection portions in which a diameter of a maximum inscribed circle drawn in a non-first intersection portion is a specific size for a shortest distance between the inflow cells or the outflow cells.

A method of making SiC nanowires comprising: (a) mixing silicon powder with a carbon-containing biopolymer and a catalyst at room temperature to form a mixture; and (b) heating said mixture to a pyrolyzing temperature sufficient to react said biopolymer and said silicon power to form SiC nanowires.

A membrane filter includes a plurality of honeycomb ceramic filtering elements, each element including a plurality of parallel ducts separated by walls and open on a face for introduction of the liquid to be filtered, an interstitial volume between the filtering elements, a filtration membrane positioned on the inner surface of the walls of the ducts, wherein the filtering elements are joined together by a curable material that forms after curing a sleeve in the form of a single part joining together, by sealing, all of the filtering elements separated the interstitial volume, the sleeve having a thickness e between 1% and 10% of the length of the filter, and the curable material being present in the open porosity and through the entire thickness of each porous wall forming the elements, over a minimum non-zero height h.