Abstract: A radio frequency module, capable of simultaneously transporting a transmission signal in a communication band B for TDD and a reception signal in a communication band A for FDD, includes a filter connected to an antenna connection terminal and having a pass band, the communication band B, a filter connected to the antenna connection terminal and having a pass band, a reception band of the communication band A, a switch to change over between the filter and a transmission input terminal to receive a transmission signal in the communication band B from an outside and the filter and a reception output terminal to supply a reception signal in the communication band B to the outside, and a band elimination filter connected between the transmission input terminal and the switch and having a stop band including the reception band of the communication band A.

Abstract: A radio frequency module includes: a radio frequency input terminal for receiving an amplified transmission signal from the outside; radio frequency output terminals for supplying a reception signal to the outside; a filter connected between the radio frequency input terminal/the radio frequency output terminal and an antenna connection terminal, and having a passband including communication band D for TDD; and a filter connected between the radio frequency output terminal and the antenna connection terminal and having a passband including at least part of communication band A allowed for simultaneous communication with communication band D. The radio frequency input terminal is arranged in a region extending along a side of the module substrate, and the radio frequency output terminal is arranged in a region extending along a side facing the side of the module substrate.

Abstract: It is to provide a high purity oxydiphthalic anhydride with which, in production of a polyimide containing an oxydiphthalic anhydride, one having sufficiently high strength can be produced, and an industrially simple process for producing it. A high purity oxydiphthalic anhydride, which has a content of fine insoluble particles having a projected area diameter of from 5 to 20 ?m, of at most 3,000 particles per 1 g, and has a light transmittance at 400 nm of at least 98.5% in a light path length of 1 cm when dissolved in acetonitrile at a concentration of 4 g/L.

Abstract: The disclosure described a process for producing an .alpha.-olefin oligomer, which comprises carrying out oligomerization of an .alpha.-olefin in a solvent in the presence of a catalytically effective amount of a chromium-based catalyst system composed of a combination of at least (a) a chromium compound, (b) a nitrogen-containing compound of at least one selected from the group consisting of an amine, an amide and an imide, (c) an alkylaluminum compound and (d) a halogen-containing compound,wherein each of the .alpha.-olefin, the chromium compound (a), the nitrogen-containing compound (b) of at least one selected from the group consisting of an amine, an amide and an imide, the alkylaluminum compound (c) and the halogen-containing compound (d) is supplied to a reaction system in a mode that the chromium compound (a) and the alkylaluminum compound (c) do not contact each other before each of said compounds (a) to (d) and the .alpha.-olefin coexists in the reaction solvent and the oligomerization of an .alpha.