Abstract: An earphone apparatus is designed for an audio device and a portable communication terminal device. The earphone apparatus includes a first plug for disconnectable connection with the audio device, and a second plug for disconnectable connection with the portable communication terminal device. An electroacoustical transducer connected to the first plug and the second plug is operative for converting a first electric signal transmitted via the first plug into corresponding sound, and for converting a second electric signal transmitted via the second plug into corresponding sound. A suitable controller provided between the first plug and the electroacoustical transducer is operative for controlling a level of the first electric signal transmitted to the electroacoustical transducer.

Abstract: The present invention provides a purification method of phosphoric acid, which includes bringing phosphoric acid containing arsenic into contact with hydrogen halide, thereby to remove the arsenic from the phosphoric acid, and a purification method of phosphoric acid, which includes bringing phosphoric acid containing arsenic into contact with hydrogen halide in the presence of a compound capable of generating hydrogen halide under acidic conditions. According to the method for purifying phosphoric acid of the present invention, a completely new method for removing arsenic in phosphoric acid is provided, which does not require a filtration or deaeration step or shows a great amount of residual sodium, unlike a sulfide coagulation method. This method is applicable to high concentration phosphoric acid, particularly polyphosphoric acid, and can be practiced at a low cost.

Abstract: The present invention provides aromatic diamine/aromatic dicarboxylate having the following formula (I) NH2—Ar1—NH2.HOOC—Ar2—COOH  (I) wherein each symbol is as defined in the specification, which is in the form of particles having a median diameter of 5-100 &mgr;m and whiteness of not less than 75. This salt has high polymerizability and preferably has superior storage stability. Therefore, it can be preferably used for the production of polybenzazole that can be formed into a fiber and a film having high strength, high elastic modulus and high heat resistance.

Abstract: The present invention provides a method for producing a formed article from a dope comprising a polyphosphoric acid solvent and a polymer soluble in polyphosphoric acid, which includes using a production apparatus containing an apparatus for stirring and uniformly dispersing or homogenizing a dope and a pump apparatus for delivering the uniformly dispersed or homogeneous dope, wherein at least one of the apparatus and the pump apparatus has a part that comes into contact with the dope. According to the present invention, maintenance frequency of production facility due to the corrosion and elution of metal in a recovered solvent can be reduced, which in turn decreases the production cost.

Abstract: The present invention provides aromatic diamine/aromatic dicarboxylate having the following formula (I)

Abstract: The present invention provides a method for producing a formed article from a dope comprising a polyphosphoric acid solvent and a polymer soluble in polyphosphoric acid, which includes using a production apparatus containing an apparatus for stirring and uniformly dispersing or homogenizing a dope and a pump apparatus for delivering the uniformly dispersed or homogeneous dope, wherein at least one of the apparatus and the pump apparatus has a part that comes into contact with the dope. According to the present invention, maintenance frequency of production facility due to the corrosion and elution of metal in a recovered solvent can be reduced, which in turn decreases the production cost.

Abstract: A method for producing polybenzazole, which comprises reacting a PBZ monomer salt with an AA-PBZ monomer or a BB-PBZ monomer in a non-oxidizing solvent having a dehydrating action to give an oligomer, and adding the AA-PBZ monomer or BB-PBZ monomer, which has not been subjected to the above reaction, to allow reaction with the oligomer, whereby to give a polymer having a desired polymerization degree. According to this method, the polymerization degree of the polymer to be obtained finally and of the polymer during production process can be easily controlled.

Abstract: A polymer having a blocked terminal group according to the present invention, represented by the following Formula (I): ##STR1## where R is an alkylene group containing 1 to 20 carbon atoms; X.sub.1 is an acyl group containing 2 to 50 carbon atoms; Y is H, an alkyl group containing 1 to 50 carbon atoms or an alkenyl group containing 1 to 50 carbon atoms; m is a positive integer; and n.sub.1 is 0 or a positive integer.

Abstract: A polymer having a blocked terminal group according to the present invention, represented by the following Formula (I): ##STR1## where R is an alkylene group containing 1 to 20 carbon atoms; X.sub.1 is an acyl group containing 2 to 50 carbon atoms; Y is H, an alkyl group containing 1 to 50 carbon atoms or an alkenyl group containing 1 to 50 carbon atoms; m is a positive integer; and n.sub.1 is 0 or a positive integer.

Abstract: A domed structure having a retractable roof comprises a field area obtained by digging out a hollow, substantially concave in section, in the ground and levelling the bottom of the hollow seats for the spectators are provided by extending an upward slope outwardly from the end of the field area in an endless manner, and a movable roof element is movably mounted on a rail element laid out on the ground adjacent to the peripheral edge of said hollow. The movable roof element includes a driving arrangement to be placed on the rail element. The rail element may be tilted with a gradient rising toward the direction of solar radiation.

Abstract: A domed structure having a retractable roof comprises an inside field area, a ringed structure vertically provided around said field area, two tracks laid out on the top of said ringed structure and two movable semi-vaults travelling separately on said two annular tracks, which are put one over the other when the roof is opened and are located in opposite relation to each other when the roof is formed, thereby providing a domed roof as a whole. The annular tracks laid out on the top of said ringed structure may have a gradient rising with respect to the direction of solar radiation.