Jx Nippon Oil Energy Corporation

Horiba Advanced Techno, Co., Ltd.

Tadashi Oshio

Kazuhiro Yagishita

Riichiro Suzuki

Toru Hirano

Tsunetoshi Sugawara

The present invention is one that makes it possible to continuously measure the resistivity of a liquid sample with accuracy as well as preventing the deterioration of the liquid sample associated with measurement, such as change in quality, and relates to a resistivity-measuring circuit C that measures the resistivity in order to sense the deterioration of the liquid sample. The resistivity-measuring circuit C is one that calculates the resistivity of the liquid sample by detecting voltage generated between an outer electrode and an inner electrode, and between the outer electrode and the inner electrode, applies square wave AC voltage having an amplitude of 1 V to 42 V and a frequency of 0.5 Hz to 30 Hz.

Resistivity-measuring circuit, cell for measuring liquid sample, resistivity-measuring apparatus, liquid sample control method, and liquid sample control system

The present invention provides a hydraulic oil composition comprising: a lubricating base oil having a kinematic viscosity at 40&#xb0; C. of 15 to 50 mm/s; and 1 to 40% by mass, based on a total amount of the hydraulic oil composition, of a polymethacrylate having a number-average molecular weight of 48000 or lower, the hydraulic oil composition having a viscosity index of 150 or higher, and a ratio (A/B) at 60 to 80&#xb0; C. of (A) a kinematic viscosity (unit: mm/s) to (B) a shear viscosity (unit: mPa&#xb7;s, shear condition: 10/s) of 1.3 or lower.

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Tokyo, Japan

Tadashi Oshio