A plugged honeycomb structure includes: a plurality of honeycomb segments, a bonding layer, and plugging portions to plug open ends of cells of the honeycomb segments. The honeycomb segment is configured so that the cells having at least two kinds of different shapes are disposed in a cross section orthogonal to an extension direction of the cells, the honeycomb segment has a center region configured by repeating units to maintain a repeated pattern including cell arrangement in which inflow cells surround an inflow cell, and a circumferential region located at the circumference of the center region, the circumferential region has open frontal area that is larger than open frontal area of the center region at the inflow end face of the honeycomb segment, the segment circumferential wall and the bonding layer have a special range of a thickness.

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.

A particulate matter measuring device component includes: a base portion formed of ceramics, the base portion being internally provided with a flow channel through which gas flows; a filter portion formed of porous ceramics, the filter portion being disposed within the flow channel so as to divide the flow channel into a plurality of portions; and a pair of electrodes for formation of electrostatic capacitance, disposed in the base portion so that the filter portion is sandwiched between the pair of electrodes, a wall surface of the flow channel of the base portion being denser than a surface of the filter portion.

A honeycomb structure includes honeycomb segments each having a porous partition wall defining a plurality of cells, and includes a porous bonding layer containing a crystalline anisotropic ceramic and disposed so as to bond side surfaces of the honeycomb segments to each other. A ratio of a pore volume (cc/g) of a fine pore defined as a pore in the bonding layer having a pore diameter of 10 m or more and less than 50 m with respect to a pore volume (cc/g) of a coarse pore defined as a pore in the bonding layer having a pore diameter of 50 m or more and 300 m or less is from 2.0 to 3.5, the pore volume of the fine pore is from 0.15 to 0.4 cc/g, and the pore volume of the coarse pore is from 0.05 to 0.25 cc/g.

A plugged honeycomb structure, including: a plurality of honeycomb segments, a bonding layer and a circumferential wall disposed to surround circumference of a honeycomb segment bonded body where the plurality of honeycomb segments are bonded, wherein in the bonding layer, the bonding layer at a part that bonds the honeycomb segments disposed in contact with the circumferential wall is a circumferential bonding layer, and the bonding layer at a part that bonds the honeycomb segment including a center of gravity in a cross section orthogonal to the extending direction of cells of the honeycomb segment bonded body or at a position closest to the center of gravity and another honeycomb segment adjacent to the honeycomb segment is a center bonding layer, and a bonding strength A1 of the circumferential bonding layer is larger than a bonding strength A2 of the center bonding layer.

A honeycomb structure including prismatic columnar honeycomb segments and a bonding layer, wherein the bonding layer has rows in each of which bonding layer portions each disposed between two honeycomb segments arranged to face each other are arranged to extend from one point of a peripheral edge of a bonded body of the honeycomb segments to the other point thereof, in a cross section, the bonding layer of each of the-rows is disposed so that among the bonding layer portions arranged in one direction, an outermost circumference bonding layer portion and at least one of the other bonding layer portions are not superimposed on each other on an extension line of the one direction, and a ratio of shift of side surfaces of adjacent honeycomb segments to a length of one side of a side surface of honeycomb segments having the same cross-sectional shape is 10% or less.

There is disclosed a plugged honeycomb structure. A plugged honeycomb structure includes a pillar-shaped honeycomb structure body having porous partition walls defining a plurality of cells which become through channels for a fluid and extend from a first end face to a second end face, and plugging portions disposed in open ends of predetermined cells in the first end face and open ends of residual cells in the second end face, and the partition walls are constituted of a porous body including -Al.sub.2O.sub.3 as a main phase and further including cordierite and Y.sub.2Si.sub.2O.sub.7.

A plugged honeycomb structure includes: a plurality of honeycomb segments, a bonding layer, and plugging portions to plug open ends of cells of the honeycomb segment. Each honeycomb segment is configured so that the cells having at least two types of different shapes have a predetermined repeated sequence pattern. A circumferential-wall partially surrounded cell in which a partition wall and a segment circumferential wall are disposed so as to surround the cell has an area of open end that has a specific ratio to an area of open end of a partition-wall entirely surrounded cell including the cross-sectional shape of the circumferential-wall partially surrounded cell. The repeated sequence pattern of the cells is kept at a boundary between two of the honeycomb segments bonded with the bonding layer at an inflow end face and an outflow end face.

A honeycomb filter includes a plurality of honeycomb fired bodies and adhesive layers. Each of the plurality of honeycomb fired bodies includes a plurality of cells, porous cell walls, and an outer wall. The plurality of cells includes exhaust gas introduction cells and exhaust gas emission cells. The exhaust gas introduction cells and the exhaust gas emission cells each have a uniform cross-sectional shape throughout from the exhaust gas inlet side to the exhaust gas outlet side excluding a plugged portion in a cross section perpendicular to a longitudinal direction of the plurality of cells. Each of the exhaust gas emission cells is adjacently surrounded fully by the exhaust gas introduction cells across the porous cell walls. The plurality of cells includes outer cells which are adjacent to the outer wall and which include the exhaust gas introduction cells.

A plugged honeycomb structure includes a plurality of honeycomb segments, a bonding layer, and plugging portions plugging open ends of cells of the honeycomb segments. The honeycomb segments include circumferential segments and central segments. The circumferential segments include at least one specific circumferential segment in which pressure loss with soot when an amount of the deposited soot is 4 g/L is higher than the pressure loss with soot of the central segment as much as 15% or more and in which an open frontal area of the circumferential segment is the same as or larger than an open frontal area of the central segment. In a cross section of a honeycomb structure body which is perpendicular to an extending direction of the cells, a ratio of an area of the specific circumferential segment is 4% or more to a total area of the circumferential segments and the central segments.