Abstract:
A semiconductor ceramic includes a BamTiO3-based composition, as a main component, having a perovskite structure represented by general formula AmBO3. Part of Ba constituting an A site is replaced with at least an alkali metal element, Bi, and a rare-earth element, and the molar ratio m between the A site and a B site is 0.990≦m≦0.999 (preferably 0.990≦m≦0.995). Preferably, part of the Ba is replaced with Ca, and the content of the Ca when the total number of moles of the elements constituting the A site is 1 mole is 0.042 to 0.20 (preferably 0.125 to 0.175) on a molar basis. A PTC thermistor includes a component body formed of the semiconductor ceramic. Accordingly, there are provided satisfactory rise characteristics even if an alkali metal element is present.
Abstract:
A semiconductor ceramic includes a BaTiO3-based composition, as a main component, having a perovskite structure represented by general formula AmBO3. Part of the A site Ba is replaced with an alkali metal element, Bi, Ca, Sr, and a rare-earth element. When the molar amounts of Ca and Sr are x and y, respectively, and the total number of moles of the elements constituting the A site is 1 mole, 0.05≦x≦0.20, 0.02≦y≦0.12, and 2x+5y≦0.7. A PTC thermistor includes a component body formed of the semiconductor ceramic. Even when an alkali metal element and Bi are present, there is provided a lead-free semiconductor ceramic with high reliability in which the surface discoloration is not caused and the degradation of resistance over time can be suppressed even after the application of an electric current for a long time.
Abstract:
A semiconductor ceramic includes a BaTiO3-based composition, as a main component, having a perovskite structure represented by general formula AmBO3. Part of the A site Ba is replaced with an alkali metal element, Bi, Ca, Sr, and a rare-earth element. When the molar amounts of Ca and Sr are x and y, respectively, and the total number of moles of the elements constituting the A site is 1 mole, 0.05≦x≦0.20, 0.02≦y≦0.12, and 2x+5y≦0.7. A PTC thermistor includes a component body formed of the semiconductor ceramic. Even when an alkali metal element and Bi are present, there is provided a lead-free semiconductor ceramic with high reliability in which the surface discoloration is not caused and the degradation of resistance over time can be suppressed even after the application of an electric current for a long time.
Abstract:
Disclosed are a projector comprising an impeller rotated at high speed by a high-speed rotation driving device and a cover for covering the outer peripheral part of the impeller and having a projection material suction port and a projection material discharge port; and a blasting machine. In the projector, the entire of the impeller or the portion of the impeller with which the projection material is collided is formed of a high wear resistant rubber. It is possible to prevent the impeller and the projection material from damage, and to improve the durability of the projector. Furthermore, projection materials having high grinding property or those having fine particles and low specific gravity may also be used for the projector. Since the weight of the projector is light, it can be rotated directly by a motor at high speed and can be used under such conditions as ultra low temperature, ordinary temperature, high moisture, etc.
Abstract:
A semiconductor ceramic having a negative temperature coefficient of resistance, the element comprising about 0.1 to 20 mol % of AMnO3 (A represents at least one of Ca, Sr, Ba, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Ho) and to a spinel composite oxide made of a solid solution of Mn and at least one element in Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Mg and Al. As a perovskite Mn composite oxide, one or more of CaMnO3, SrMnO3, BaMnO3, LaMnO3, PrMnO3, NdMnO3, SmMnO3, EuMnO3, GdMnO3, TbMnO3, DyMnO3 and HoMnO3 may be used.
Abstract:
Activated carbon is prepared specially by activating carbonaceous material in a circumstance comprising water vapor less than 15% on volume basis and providing thus treated activated carbon carries alkaline or alkaline earth metal sulfide in it. Thus prepared activated carbon or that carrying these compound provides for method of eliminating mercury and its compounds from liquid hydrocarbons substantially completely contained at a slight amount in it. Liquid hydrocarbons containing mercury or sulfur will harm catalysts which are often applied during process for such intermediates of petroleum products and petrochemical products. Thus the present method is advantageous to processing of such oil intermediates.
Abstract:
A soft synthetic resin, such as polyurethane, body is molded onto a metallic steering wheel frame except for a part thereof intended for installation of the steering wheel onto a column shaft and a soft burr formed on the resultant covered steering wheel along the parting line of the mold is removed by refrigerating the steering wheel to make the burr hard and fragile and then removing the burr by shot blast treatment, whereafter the steering wheel is heat dried to eliminate water from the atmosphere condensing on the exposed metallic installation part of the steering wheel and prevent resulting corrosion of that part.
Abstract:
A semiconductor ceramic and a positive-coefficient characteristic thermistor are provided which have a stable PTC characteristic, a high double point, and a wide operating temperature range. The semiconductor ceramic contains, as a main component, a barium titanate-based composition having a perovskite structure expressed by a general formula AmBO3. Out of 100 mol % of the Ti, an amount in a range of 0.05 mol % or more to 0.3 mol % or less of Ti is replaced with W as a semiconductor forming agent, the ratio m of A sites mainly to B sites is 0.99≦m≦1.002, and an actually-measured sintered density is 70% or more and 90% or less of the theoretical sintered density. In the positive-coefficient characteristic thermistor, a component body is formed of the semiconductor ceramic.
Abstract:
The upper opening which opens the blast-processing chamber can be opened after the door moves slidely to the up and down directions, the door does not project outwardly from the case when the door is opened, it can be installed to the small space. Also it can be prevented to collide against the door.
Abstract:
A cylindrical member is placed in a dead-end hole formed in a housing made of a material such as aluminum. A peripheral portion of the hole is pressed down to plastically deform the housing material and to supply the deformed material into a groove formed on an outer periphery of the cylindrical member. The cylindrical member is calked to the housing in this manner. To supply a proper amount of deformed material into the groove for obtaining a quality calking, an inflection point of a calking curve indicating a relation of a calking force and a calking stroke is detected during the calking process. After the inflection point is detected, the calking is performed by giving a predetermined calking stroke or by adding a predetermined calking force.