Abstract: A test recording is performed with respect to an optical disc prior to a regular recording, and a ? value for setting a qualitative parameter relating to the level of the recording state within a preferable range is derived from a result of the test recording. Then, the recording velocity at which the derived ? value or the writing laser power value is within the preferable value can be obtained. Therefore, the recording velocity at which the satisfactory recording can be realized with few recording errors can be determined. Further, a relation between a writing laser power value and a ?? value is obtained from the reproduced signal from the test record area, and the writing laser power value is determined considering the ?? value.

Abstract: A threaded joint for steel pipes comprising a pin 1 and a box 2 each having a contact surface comprising a threaded portion 3 or 4 and an unthreaded metal contact portion 8 is provided with improved anti-galling propertied by forming a lubricating coating on the contact surface of at least one of the pin and the box, the lubricating coating exhibiting a self-repairing function by liquid lubrication and having a decreased greasiness. The lubricating coating is (1) a coating which comprises a lower lubricant layer which is in liquid form in the temperature range of above 0° C. and below 40° C. and an upper lubricant layer which is in solid form at 40° C., or (2) a coating which is semi-solid or solid at 40° C. and is formed of a mixture comprising a lubricating oil which is in liquid form in the temperature range of above 0° C. and below 40° C. and a wax which is in solid form at 40° C.

Abstract: A threaded joint for steel pipes which is capable of metal-to-metal sealing and which can be subjected to repeated fastening and unfastening without the application of a liquid lubricant containing a heavy metal powder comprises a pin and a box each having a contact surface including a threaded portion and an unthreaded metal contact portion. The contact surface of at least one of the pin and the box are coated with an undercoating layer and a lubricating coating layer atop it. The undercoating layer is a porous metal coating having a porosity of 5-80% and a thickness of 1-30 &mgr;m and preferably a hardness of 50-250 Hv. The lubricating coating is a solid lubricating coating or a liquid lubricating coating, the latter containing substantially no heavy metal powders. The total thickness of the undercoating layer and the lubricating coating layer is at most 100 &mgr;m.

Abstract: An optical disc recording method comprises the steps of: setting a recording parameter function representing a relationship between a recording velocity for recording data to an optical disc and a parameter for optimally controlling a recording power controlling waveform for controlling a recording power of a light beam irradiated to the optical disc for recording the data; obtaining an optimal value for the parameter by executing a test recording at one recording velocity or at a plurality of recording velocities to a test area of the optical disc before actual data recording to the optical disc; correcting the recording parameter function in accordance with the obtained optimal value for the parameter; deriving the parameter corresponding to a recording velocity from the corrected recording parameter function; and recording the data by irradiating a light beam of the recording power controlling waveform to which the obtained parameter is applied.

Abstract: This invention relates to a threaded joint for steel pipes which comprises a pin and a box each having a contact surface including a threaded portion and an unthreaded metal contact portion and which guarantees galling resistance and gas tightness in a stable manner without application of a compound grease. A solid lubricating coating comprising a lubricating powder (e.g., molybdenum disulfide) and an organic or inorganic binder is formed on the contact surface of at least one of the pin and the box. The proportion of area of a cross section along the thickness of the solid lubricating coating which is occupied by secondary particles of the lubricating powder having an equivalent circular diameter of 15-60 &mgr;m is from 5-90%. Alternatively, the solid lubricating coating comprises, in addition to the lubricating powder, a fibrous filler (e.g., inorganic whiskers) in such an amount that the mass ratio of the fibrous filler to the binder is 0.01-0.5.

Abstract: This invention relates to a threaded joint for steel pipes which comprises a pin and a box each having a contact surface including a threaded portion and an unthreaded metal contact portion and which guarantees galling resistance and gas tightness in a stable manner without application of a compound grease. A solid lubricating coating comprising a lubricating powder (e.g., molybdenum disulfide) and an organic or inorganic binder is formed on the contact surface of at least one of the pin and the box. The proportion of area of a cross section along the thickness of the solid lubricating coating which is occupied by secondary particles of the lubricating powder having an equivalent circular diameter of 15-60 &mgr;m is from 5-90%. Alternatively, the solid lubricating coating comprises, in addition to the lubricating powder, a fibrous filler (e.g., inorganic whiskers) in such an amount that the mass ratio of the fibrous filler to the binder is 0.01-0.5.

Abstract: A method is designed for writing data originally recorded in a source disk medium with an original reproduction signal quality, into an object disk medium by means of an optical recording apparatus having a machine parameter settable to control a reproduction signal quality of data. The method is carried out by the steps of measuring the original reproduction signal quality of the data originally recorded in the source disk medium, setting a value of the machine parameter of the optical recording apparatus in accordance with the measured original reproduction signal quality, and writing the data into the object disk medium by means of the optical recording apparatus so as to secure the reproduction signal quality of the written data comparable to the original reproduction signal quality.

Abstract: An optical disk recording apparatus is designed for recording information on an optical disk by irradiation of a laser beam according to a given control procedure under a given recording condition. In the optical disk recording apparatus, an acquiring section acts when an operation of recording information is performed for acquiring the recording condition associated to the operation to be performed. A selecting section selects a control procedure according to the acquired recording condition from a plurality of different control procedures which are prepared beforehand. A control section controls the irradiation of the laser beam according to the selected control procedure during the operation of recording information. The selecting section selects the control procedure effective to enable the control section to regulate an irradiation power of the laser beam with a regulation accuracy matching a quality level of recording information indicated by the acquired recording condition.

Abstract: A method is designed for controlling a power of a laser beam irradiated onto a track of an optical disc for recording of data at a given linear velocity.

Abstract: Prior to a main record, a trial write of data in an optical disc is performed in accordance with the characteristics between a record velocity and an optimum record power (Steps S2 to S4). The quality of a signal reproduced from the trial-written data is measured (Step S5). It is judged from the measured quality of the reproduced signal whether the predetermined velocity is a recordable velocity satisfying the characteristics between the record velocity and the optimum record power (Step 5). The main record is executed in accordance with the judgment result.

Abstract: A test recording is performed with respect to an optical disc prior to a regular recording, and a &bgr; value for setting a qualitative parameter relating to the level of the recording state within a preferable range is derived from a result of the test recording. Then, the recording velocity at which the derived &bgr; value or the writing laser power value is within the preferable value can be obtained. Therefore, the recording velocity at which the satisfactory recording can be realized with few recording errors can be determined. Further, a relation between a writing laser power value and a &Dgr;&bgr; value is obtained from the reproduced signal from the test record area, and the writing laser power value is determined considering the &Dgr;&bgr; value.