Abstract: A process oil which satisfies the requirements of (a) a content of a polycyclic aromatic compound of less than 3% by weight, (b) a content of an aromatic hydrocarbon of 18% by weight or more, (c) a content of a polar compound ranging from 11 to 25% by weight, (d) a kinematic viscosity at 100° C. ranging from 10 to 70 mm2/s, and (e) a flash point of 210° C. or more.

Abstract: A process oil which satisfies the requirements of (a) a content of a polycyclic aromatic compound of less than 3% by weight, (b) a content of an aromatic hydrocarbon of 18% by weight or more, (c) a content of a polar compound ranging from 11 to 25% by weight, (d) a kinematic viscosity at 100° C. ranging from 10 to 70 mm2/s, and (e) a flash point of 210° C. or more.

Abstract: Process oil which satisfies requirements that a content of a polycyclic aromatic compound is less than 3% by weight, a content of an aromatic hydrocarbon is 18% by weight or more, a content of a polar compound is between 11 and 25% by weight, a kinematic viscosity at 100° C. is between 10 and 70 mm2/s, and a flash point is 210° C. or more.

Abstract: An adaptive communication apparatus for use in a multicarrier transmission system in which data sequence to be transmitted is divided into a plurality of data sequences, and these data sequences are converted into a high-frequency signal including a plurality of carriers allocated different frequencies and radio-transmitted in parallel. In the adaptive communication apparatus, a received high-frequency signal is separated into a plurality of carriers by a wave separator. The frequency characteristic of the received high-frequency signal is corrected by a frequency characteristic compensation unit. The frequency characteristic compensation unit is controlled by a controller through use of the high-frequency signal subjected to signal processing by the frequency characteristic compensation unit and the wave separator.

Abstract: A differential detector (2) reproduces a spreading code (S2) of a received signal (S1). A digital correlator (4) calculates a correlation value between the reproduced spreading code (S2) and a reference spreading code (S3) by collating bit by bit. The timing when the correlation value exceeds a predetermined threshold value (D2) means that the reproduced spreading code (S2) and the reference spreading code (S3) match in phase. A phase of the reproduced spreading code (S2), or a phase of the received signal (S1), is discriminated at that timing. A multiplier (8) outputs a modulated signal (S6) by multiplying the received signal (S1) bit by bit in phase by a spreading code (S5) which has the same code as the reference spreading code (S3). In result, a spreading code with an accurate code sequence and phase is obtained for despreading, and theoretical process-gain is obtained.