Abstract: In a method of measuring an exchange force between a specimen and a probe, the specimen and probe are faced to each other with a distance within a close proximity or RKKY-type exchange interaction region from a distance at which conduction electron clouds begin to be overlapped with each other to a distance at which localized electron clouds are not substantially overlapped with each other, a relative displacement of the specimen and probe is detected to measure a first force under such a condition that directions of magnetic moments of said specimen surface and probe are in parallel with each other to derive a first force and under such a condition that directions of magnetic moments of said specimen surface and probe are in anti-parallel with each other to derive a second force. An exchange force is derived as a difference between said first and second forces. Magnetic property of the specimen can be evaluated on the basis of the thus measured exchange force.

Abstract: In an apparatus for measuring an exchange force between a specimen and a probe, the specimen and probe are faced to each other with a distance within a close proximity or RKKY-type exchange interaction region from a distance at which conduction electron clouds begin to be overlapped with each other to a distance at which localized electron clouds are not substantially overlapped with each other. In order to prevent the probe from being attracted to the specimen by a force between the specimen and the force, a piezoelectric element is provided on a cantilever and a control signal supplied to the piezoelectric element is produced in accordance with a displacement of the cantilever to control a spring constant of the cantilever. The exchange force between the specimen and the probe is calculated from the control signal supplied to the piezoelectric element.

Abstract: A calcium-phosphorus apatite is obtained by reacting a calcium compound with a phosphorus compound under reflux in a reaction medium consisting mainly of an organic solvent and water.

Abstract: An apparatus for making biaxially stretched tubular films of thermoplastic synthetic resin which permits operation in a stabilized manner and economically by using the hot air used in stretching a bubble again in heating a raw film. In said apparatus, a suction ring is provided in the section where a heated raw film is inflated by the gas filled therein under pressure, and the diameter of the resulting stretched bubble reaches its maximum diameter. The suction ring sucks the air used for heating the stretching part simultaneously with the air used for cooling it after stretching to attain a thermal interception effect between the stretching part and the cooling part after stretching. Air flow around the stretching bubble is made uniform.

Abstract: An apparatus for producing tubular plastic films having extremely small variation of flat width in stabilized manner is provided. Said apparatus comprises a blower, a valve for controlling the amount of air, an air reservoir, a connecting pipe for connecting these blower, valve and air reservoir and another connecting pipe which connects said reservoir to the inside of a bubble formed on the tip end of a mold fixed to the outlet of an extruder through said mold to feed or discharge the air into the inside of said bubble continuously in a non-step manner, thereby to keep the inside pressure of said bubble uniform.

Abstract: A method for rendering initiation of stretching easier in the production of biaxial stretched film of plastic tube carried out by enclosing gas in said tube and by the difference in the peripheral velocity between delivery nip rolls and take-up nip rolls is provided. This method is characterized by passing said tube between at last one pair of nipping means for enclosing gas, having therebetween a clearance adjustable in the range of 1.about.10 mm. The nipping means are provided before or behind said take-up nip rolls and driven at a peripheral speed same as that of said take-up nip rolls.

Abstract: An apparatus for producing biaxially stretched tubular films which enables heating air for stretching to pass uniformly around the circumference of a stretching bubble thereby to effect stabilized operation. Said apparatus comprises 1 a circular hood fitted to the section where a loaded raw film starts stretching and a formed stretching bubble expands to its maximum diameter, 2 holders for a plurality of rolls, which holders are mounted on the lower part of said hood, said rolls being held each on the end of said holders which an elasticity allowing swinging of said rolls only in the direction radial to the central axis of said bubble but resistant to being distorted in the direction of circumference of said stretching bubble, and 3 a flexible and shrinkable cylindrical sheet attached to and along the inside lower surface of said hood, the lower end of said sheet being situated immediately above the roll part of said holders.