Abstract: There is provided a method for hoisting and lowering a device in a rotor head of a wind turbine generator, that can easily perform a device hoisting and lowering operation in the rotor head without an external crane. The method for hoisting and lowering a device in a rotor head includes a step of mounting a temporary winch rail to a rail support portion previously provided in the rotor head, a step of installing a temporary winch on the temporary winch rail, a step of opening a maintenance hatch provided in the rotor head, and a step of hoisting and lowering a replacement device to be attached or removed in the rotor head through a hoisting and lowering opening in the maintenance hatch by the temporary winch.

Abstract: There is provided a wind turbine generator that includes an improved grease supply and discharge system of lubricant oil used in a blade rotating ring bearing of a wind turbine blade, and can reliably recover discharged grease. The wind turbine generator includes a pitch control mechanism that can adjust a pitch angle of the wind turbine blade via the blade rotating ring bearing provided between the wind turbine blade and a rotor head, a grease supply and discharge device is provided in the rotor head, and the grease supply and discharge device includes a grease supply device that pumps lubricant oil in a supplied grease tank with a grease supply pump and supplies the lubricant oil to the blade rotating ring bearing, and a grease discharge device that forcibly sucks and recovers the discharged grease from the blade rotating ring bearing.

Abstract: The present invention provides a wind turbine generator in which an oil seal structure provided in a blade rotating ring bearing of a wind turbine blade is improved and leakage of lubricant oil to outside is prevented or suppressed.

Abstract: The invention relates to a multilayer ceramic capacitor having dielectric layers and internal electrode layers disposed alternately. The dielectric layers include a dielectric ceramic containing barium titanate as a main component, and also calcium, magnesium, vanadium, manganese, and a rare-earth element. Crystals constituting the dielectric ceramic are constituted by grains containing barium titanate as their main component and containing calcium in a concentration of 0.2 atomic % or less or containing the calcium in a concentration of 0.4 atomic % or more. The crystals grains are also distinct in their relative distributions of magnesium and rare-earth elements between the center of the grain and the surface of the grain. Finally, the relative areas of the two kinds of crystals observed in the plane of a polished surface of the dielectric ceramic are described by a ratio b/(a+b), which is 0.5 to 0.8.

Abstract: A crystal constituting a dielectric porcelain, comprised of a first crystal group composed of crystal grains of 0.2 atomic % or less calcium concentration and a second crystal group composed of crystal grains of 0.4 atomic % or more calcium concentration, wherein the ratio of concentration of each of magnesium and a first rare earth element contained in a center portion to that contained in a surface layer portion of crystal grains constituting the first crystal group is greater than the corresponding concentration ratio of crystal grains constituting the second crystal group, and wherein on a polished surface resulting from polishing of the surface of the dielectric porcelain, when the area of crystal grains of the first crystal group is referred to as a and the area of crystal grains of the second crystal group referred to as b, the ratio of b/(a+b) is in the range of 0.5 to 0.8.

Abstract: [Problems] To provide a multilayered ceramic capacitor which in a high-temperature loading test, can be inhibited from decreasing in insulation resistance with time and which can have high insulating properties even when produced without via a reoxidation step. [Means for Solving Problems] The multilayered ceramic capacitor is formed by alternately superposing dielectric layers made of dielectric porcelain and inner-electrode layers. The dielectric porcelain is constituted of first crystals comprising crystal particles comprising barium titanate as the main component and having a calcium concentration of 0.2 at. % or lower and second crystals comprising crystal particles having a calcium concentration of 0.4 at. % or higher.

Abstract: A dielectric ceramics comprising a high dielectric constant is disclosed. The dielectric ceramics also comprises a relative dielectric constant with a stable temperature dependence and an insulation resistance with a reduced voltage dependence. The dielectric ceramics can be used to form a multilayer ceramic capacitor that has a long life.

Abstract: A multilayer ceramic capacitor comprises a dielectric layer and an internal electrode layer that are alternately laminated. Barium titanate particles containing an alkaline earth metal component except for Ba in a proportion of not more than 0.2 atomic % (BMTL), and barium titanate particles containing an alkaline earth metal component except for Ba in a proportion of not less than 0.4 atomic % (BMTH) coexist in the dielectric layer in an area ratio of BMTL to BMTH of 0.1 to 9. This provides excellent reliability of capacity temperature characteristic and high-temperature load lifetime, if the dielectric layer is thinned.

Abstract: A multilayer ceramic capacitor comprises a dielectric layer and an internal electrode layer that are alternately laminated. Barium titanate particles containing an alkaline earth metal component except for Ba in a proportion of not more than 0.2 atomic % (BMTL), and barium titanate particles containing an alkaline earth metal component except for Ba in a proportion of not less than 0.4 atomic % (BMTH) coexist in the dielectric layer in an area ratio of BMTL to BMTH of 0.1 to 9. This provides excellent reliability of capacity temperature characteristic and high-temperature load lifetime, if the dielectric layer is thinned.

Abstract: A dielectric ceramic composition containing, per 100 parts by weight of BaTiO.sub.3, at least either one of Nb.sub.2 O.sub.5 or Ta.sub.2 O.sub.5 in an amount of from 0.8 to 3.5 parts by weight, MgO in an amount of from 0.06 to 0.7 parts by weight, oxides of rare earth elements in an amount of from 0.005 to 0.520 parts by weight, and MnO in an amount of from 0.01 to 0.30 parts by weight in the form of MnCO.sub.3, the molar ratio of MgO to either Nb.sub.2 O.sub.5 or Ta.sub.2 O.sub.5 being from 0.5 to 2.2. The dielectric ceramic composition has a dielectric constant of not smaller than 2500, is fired at a temperature of not higher than 1300.degree. C., exhibits a change of capacitance depending upon the temperature satisfying X7R of the IEA Standards, a dielectric loss of not larger than 2.5%, a small voltage dependence, and an insulation resistance of not smaller than 10.sup.4 M.OMEGA., and is suited as a material for producing ceramic capacitors and resonators.

Abstract: A multilayer substrate with inner capacitors comprising a dielectric layer sandwiched between upper and lower insulating layers, a couple of printed electrodes in desired patterns within the thickness of the dielectric layer so as to form each capacitor at the portion of the dielectric layer corresponding to the electrodes, and a couple of leading terminals on one surface of the insulating layer, which communicate with the electrodes, the multilayer substrate being characterized in that the dielectric layer is composed of a ceramic composition mainly comprising MTiO.sub.3 -based ceramics (M represents one or several of Ba, Ca, Mg, La, Sr and Nd) and the insulating layer is composed of a ceramic composition mainly comprising MgO-SiO.sub.2 -CaO-based ceramics, which is defined by an area surrounded by the lines connecting points A, B, C, D, E, F and G as shown in FIG. 1 and listed below, wherein X, Y and Z respectively represent weight percent values of MgO, SiO.sub.2 and CaO at points A, B, C, D, E, F and G.