Abstract: A particulate matter concentration measuring apparatus configured to measure a concentration of a particulate matter in an exhaust gas that flows through a diesel engine exhaust line includes an exhaust gas collecting line, a particulate matter detection filter, and a differential pressure detecting unit. The exhaust gas collecting line branches from the diesel engine exhaust line and includes a flow path cross-sectional area smaller than a flow path cross-sectional area of the diesel engine exhaust line. The particulate matter detection filter is disposed in the exhaust gas collecting line. The differential pressure detecting unit is configured to detect a differential pressure between an inlet and an outlet of the particulate matter detection filter and disposed apart from a downstream end of the particulate matter detection filter in a direction of a flow of the exhaust gas.

Abstract: A particulate matter concentration measuring apparatus is configured to measure a concentration of particulate matter in exhaust gas flowing through an exhaust line of a diesel engine. The apparatus includes an exhaust gas extraction line diverging from the exhaust line and having a flow passage cross-sectional area smaller than a flow passage cross-sectional area of the exhaust line. A particulate matter detection filter has a cell wall and is provided in the exhaust gas extraction line. A flow velocity of the exhaust gas passing through the cell wall is more than or equal to approximately 0.02 m/s and less than or equal to approximately 2.0 m/s. A differential pressure sensing part is configured to sense a differential pressure generated between an inlet and an outlet of the particulate matter detection filter.

Abstract: An optical head device may include a frame type of laser beam emitting element provided with a heat radiating fin on which a laser chip is mounted, a device frame on which the laser beam emitting element, a light receiving element and an optical system are mounted, and a heat radiation member formed of material having a superior heat conduction property. The upper face of the laser beam emitting element is fixed to the device frame, and an under face of the heat radiating fin which corresponds to a portion where the laser chip is mounted is exposed on an outer side to form an exposed part, and the heat radiation member is disposed to extend over the exposed part and the device frame.

Abstract: A honeycomb structure is a pillar-shaped honeycomb structure in which a plurality of cells, separated from each other by a cell wall, are formed in a longitudinal direction. When the honeycomb structure is divided into two portions by a plane in parallel with either one of end faces in the longitudinal direction of the honeycomb structure so that apparent volumes of the respective two portions become equal to each other, the respective two portions have apparent densities different from each other.

Abstract: A fixing structure of an optical element such as a half mirror may include an optical element, a fixing member such as a frame which is formed with a reference surface, a first adhesive and a second adhesive which are used to fix the optical element on the reference surface. The first adhesive is coated so as to extend over the reference surface and the optical element, and the second adhesive is coated at a position where separation of the optical element from the reference surface due to thermal expansion of the first adhesive is restricted. An exposed side of the first adhesive is preferably formed in an opposite direction to an exposed side of the second adhesive with respect to the reference surface.

Abstract: An optical head device may include a frame type of laser beam emitting element provided with a heat radiating fin on which a laser chip is mounted, a device frame on which the laser beam emitting element, a light receiving element and an optical system are mounted, and a heat radiation member formed of material having a superior heat conduction property. The upper face of the laser beam emitting element is fixed to the device frame, and an under face of the heat radiating fin which corresponds to a portion where the laser chip is mounted is exposed on an outer side to form an exposed part, and the heat radiation member is disposed to extend over the exposed part and the device frame.

Abstract: A honeycomb structured body of the present invention is a honeycomb structured body in which a plurality of cells are placed in parallel with one another in the longitudinal direction with a cell wall therebetween, either one of the end portions of the cells being sealed, wherein a porosity is at least about 70% and at most about 95%, and a ratio of a diameter of a cross-section perpendicular to the longitudinal direction of the honeycomb structured body to a length of the honeycomb structured body in the longitudinal direction is at least about 0.2 and at most about 0.9.