Abstract: A polyimide excelling in heat resistance, chemical resistance, water repellency, dielectric characteristics, electrical characteristics, and optical characteristics and a polyamide acid useful as the raw material therefor are provided. Specifically, a polyamide acid containing a chlorine atom and a fluorine atom and comprising a repeating unit represented by the following formula (1): (wherein X and X? independently denote a divalent organic group; Y and Y? independently denote a chlorine, bromine, or iodine atom; p and p? denote independently denote the number of fluorine atom {F in the formula (1)} bonded to the relevant benzene ring, representing an integer of 0-3; q and q? independently denote an integer of 0-3; and p+q total 3, and p?+q? total 3).

Abstract: A cleaning tool for an optical connector includes a cylindrical cleaner and a holding member for holding a proximal portion of the cleaner. The cleaner has a main body with a ferrule insertion hole extending from a ferrule insertion port at its distal end face toward the proximal end of the cleaner. The ferrule insertion hole has an inner diameter substantially the same as an outer diameter of a ferrule. The ferrule insertion hole is surrounded by a rough surface so as to clean an outer surface of the ferrule which is to be inserted.

Abstract: LAN device and tools can be connected only by optical fiber cables without providing a space for additional LAN devices and tools and changing an electric connector interface of the LAN devices and tools already established.

Abstract: A low-cost, high-reliability polarization-independent optical waveguide interferometer is proposed which does not bring about any additional job involved in the insertion of a half-wave plate or excess loss of light. In an optical multi/demultiplexer utilizing optical interference of light waves passing through a plurality of optical waveguides with different lengths, such as an AWG and a Mach-Zehnder interferometer, longitudinal integral values of birefringence values of the individual waveguides, which values are variable or invariable along the waveguides, are made equal for all waveguides 201 and 202. Thus, simply varying the waveguide width can implement polarization-independent operation, or on the contrary implement a polarization beam splitter.

Abstract: For measurement of a liquid level, an optical fiber connected at its one end portion to force receiving means movably arranged in liquid to receive force from the liquid is dipped in the liquid together with the force receiving means, and a change in the force acting on said force receiving means when the liquid level changes is detected as a change in strain in the optical fiber by means of an optical fiber strain gauge connected to the other end of the optical fiber, thus measuring a water level of the liquid.

Abstract: The cleaning tool for optical fiber connectors has cleaning sheet laminated to the bottom surface of a front plate. A plurality of rows of slit shaped windows are opened through the front plate. Peel-off sheet is attached to the front plate to close off the windows. Peel-off sheet sealing off the windows is removed to open a window, an optical fiber connector is moved within the exposed window, and the connecting surface of the optical fiber connector is cleaned by the cleaning sheet.

Abstract: A grooved substrate which has a groove for aligning or positioning an optical fiber therein and which can be advantageously used in a multifiber optical connector or for aligning a multiple optical fiber is formed of an amorphous alloy possessing at least a glass transition region, preferably a glass transition region of not less than 30 K in temperature width. Particularly, the amorphous alloy of M1—M2 system or M1—M2—La system (M1: Zr and/or Hf, M2: Ni, Cu, Fe, Co, Mn, Nb, Ti, V, Cr, Zn, Al, and/or Ga, La: rare earth element) possesses a wide range of &Dgr;Tx and thus can be advantageously used as a material for the grooved substrate. Such a grooved substrate can be manufactured with high mass-productivity by a metal mold casting method or molding method.

Abstract: An x-ray generation apparatus includes an x-ray reflecting mirror and x-ray generation part. The x-ray reflecting mirror is formed on an inner surface of a concave aspheric surface. The x-ray generation part receives at least one incident energy beam. The x-ray generation part is arranged near a focal point including a focal point of a paraboloid, and the x-ray reflecting mirror has at least one aperture formed in a position except for a part of the concave aspheric surface crossing an axis including the focal point of the concave aspheric surface, and an incident energy beam irradiates the x-ray generation part through the aperture.

Abstract: A cleaning tool for an optical connector cleans a connecting end face of a ferrule fixed to an optical connecting plug, and includes a cleaning sheet and a plug holding member. The cleaning sheet cleans the connecting end face of the ferrule. The plug holding member holds the optical connecting plug such that the connecting end face of the ferrule comes into contact with the cleaning sheet to be parallel to it.

Abstract: An optical fiber coupler according to the present invention comprises two optical fibers which each include a core portion serving to propagate light and a clad portion surrounding said core portion, the two optical fibers extending substantially in parallel in a same flat plane, and a melting portion in which the clad portions of the two optical fibers are fused together substantially in a line contact. Two optical fibers are arranged in parallel to permit at least parts of the clad portions to be brought into contact with each other. In this state, the two optical fibers are heated and fused mutually substantially in a line contact and are further drawn for fabrication thereof. The optical fibers are heated preferably employing an electric ceramic microheater. The two optical fibers may be same or different in structural parameters.

Abstract: A person to be authenticated generates authentication data for this time and authentication data for next time using a one-way function, based on a user ID, a password and a random number, and performs an exclusive OR operation on these, to thereby encrypt the data while associating the both parameters with each other, and transmits these data together with the own user ID to an authenticating person. The authenticating person receives the aforesaid three informations, compares a validity confirmation parameter calculated by using a one-way function based on the authentication data for this time with a authentication parameter registered in the previous authentication phase, and when these parameters agree with each other, judges that authentication is approved, and registers the authentication data for next time as the authentication parameter for next time.

Abstract: There is provided a liquid-level gauge for accurately measuring a liquid-level height of fluid to be measured. In the liquid-level gauge, a float having a uniform cross-sectional form in the height direction and a specific weight value small than that of liquid is dipped in the liquid. The float is supported by an optical fiber at a constant height such that its upper end always projects from the liquid level. One end of the optical fiber is connected to an optical fiber strain gauge and a strain detector is turned round between fiber support members. When the float receives buoyancy from the liquid, tension is applied to the strain detector of optical fiber to generate strain therein. By detecting the strain by means of an optical fiber strain gauge, a liquid-level height can be measured.

Abstract: There is disclosed a method for producing a diamond film for lithography wherein a diamond film is formed on a silicon substrate on which an insulating film is formed or on an insulating substrate using a mixed gas of methane gas, hydrogen gas and oxygen gas as a raw material gas, and then the substrate is removed by etching treatment, and a method of producing a mask membrane for lithography wherein diamond particles fluidized with gas are brought into contact with a surface of a silicon substrate on which an insulating film is formed or an insulating substrate, a diamond film is grown on the substrate, and then the substrate is removed by etching treatment. There can be provided a method of producing a diamond film for lithography wherein a diamond film having high crystallinity and desired membrane stress can be formed on a substrate, and the film can be easily produced without degrading smoothness, membrane stress or the like after film formation.

Abstract: An optical fiber coupler receptacle member having simple construction with superior molding ability and can easily perform fixing and coupling operation. The optical fiber coupler receptacle member has a base body formed with a receptacle groove adapting to a shape of an optical fiber coupler having coated fiber portions, bear fiber portions and a molten and elongated portion, and a cover engaged with and covering the base body in order to protect the optical fiber coupler fixed to the base body.

Abstract: A cleaning tool for cleaning optical fiber connectors exposes a cleaning sheet in a window of the case. A winding pulley is operable to wind the cleaning sheet upon rotation at a constant pitch. A rotation mechanism, that is operated by a lever, rotates the winding pulley. The case is constructed of a first front plate and a second front plate which are closed off by a perimeter wall along their outer circumference. The case has an open portion in a part of the perimeter wall, and the lever is disposed in the open portion in an inclined orientation.

Abstract: A water repellent coating composition includes fine particles having functional groups on their surfaces and having a particle diameter ranging from 10 nm to 1 mm; a coupling agent containing (a) a functional group which is capable of reacting with the functional group of the fine particles and (b) a water repellent fluorinated group; a binder resin for binding the fine particles; and a solvent for the binder.

Abstract: An optical connector ferrule has an optical fiber incorporated therein as an integral part thereof, wherein the optical fiber is integrally fixed in the ferrule directly or through the medium of the metal tube embedded in the ferrule. This ferrule of the optical fiber built-in type can be produced by inserting an optical fiber or a metal tube having an optical fiber fitted therein into a mold provided with a molding cavity which defines the outer shape of an optical connector ferrule, injecting a fluid material kept at an elevated temperature into the cavity of the mold, and solidifying the cast material by cooling. The optical fiber or both the optical fiber and the metal tube are strongly fixed in the ferrule integrally by the thermal shrinkage or coagulation shrinkage of the ferrule during the production thereof.

Abstract: A water-repellent coating has tetrafluoroethylene resin powder, silicone resin binder, and organic solvent. The tetrafluoroethylene resin powder has a ratio of the peak absorbance at 1,800 cm−1 to the peak absorbance at 500 cm −1 of 0.0001 to 0.05 exclusive. A coating film is formed by applying such a coating on a substrate. The coating has the properties of high water repellency, excellent anti-ice-coating, excellent anti-snow-coating, and so on, in spite of not having a large amount of fluororesin powder. In addition, the coating of film keeps the water repellency regardless of whether the coating film is immersed into water for a long time.

Abstract: A person to be authenticated generates authentication data for this time and authentication data for next time using a one-way function, based on a user ID, a password and a random number, and performs an exclusive OR operation on these, to thereby encrypt the data while associating the both parameters with each other, and transmits these data together with the own user ID to an authenticating person. The authenticating person receives the aforesaid three informations, compares a validity confirmation parameter calculated by using a one-way function based on the authentication data for this time with a authentication parameter registered in the previous authentication phase, and when these parameters agree with each other, judges that authentication is approved, and registers the authentication data for next time as the authentication parameter for next time.