Abstract: A mesophase pitch-based carbon fiber for use as a material for a negative electrode of a secondary battery, and a process for producing the same. The mesophase pitch-based carbon fiber comprises a columnar core part having a texture composed of a plurality of graphite layers extending along an axial direction and extending with minute flexures in a plane perpendicular to the axis and an outer-shell part surrounding the core part. The outer-shell part has a texture composed of a laminate of a plurality of graphite layers extending along an axial direction. The graphite layers are oriented in a plane perpendicular to the axis in a fashion such that the graphite layers extend along a circumferential direction with minute flexures while gradually receding from a center of the core part.

Abstract: An ozonizer in which a pair of plate-like electrode plates are arranged opposite to each other so as to form a discharge space therebetween, and ceramic dielectric layers are arranged on the surface on the side of the discharge space of said electrode plates, wherein a plate-like anode 4 is arranged between the dielectrics 31 and 32, extreme ends 41 and 42 having sharp extreme ends of a number of protrusions are formed on both surfaces of the anode 4, the anode 4 is arranged between the dielectrics 41 and 42 in a state where the extreme ends 41 and 42 are in contact with the surfaces of the dielectrics 31 and 32 on both sides, the anode 4 is formed with a number of through-holes extending through both surfaces, and the anode being formed of expanded metal.

Abstract: An ozone production apparatus for increasing ozone generation efficiency by improving ceramic plate cooling efficiency. An ozonizer of this invention has a steel plate shaped body for use as a discharge electrode through which gas is permeable from one surface to another. This discharge electrode is faced on both sides by two ceramic plates, with a material gas flow inlet provided on one side and an ozone flow outlet on the other side. The ozonizer unit is provided with an insulated waterproof cable for applying a high voltage to the discharge electrode. This ozonizer unit is submerged inside a cooling water tank, and a high voltage, high frequency power supply unit is connected between the discharge electrode and the cooling water, with the cooling water tank as the grounded side. In this manner, since the ozonizer unit is submerged inside the cooling water tank, the cooling efficiency is improved and the ozone generation increased.

Abstract: A miniaturized, thin coil component with enhanced heat radiation and decreased flux leakage includes an I-shaped laminate iron core having at opposite ends tapered surfaces, and a pair of C-shaped laminate iron cores having tapered surfaces adapted to be mated with the tapered surfaces of the I-shaped laminate iron core. The I-shaped laminate iron core and the C-shaped laminate iron cores are combined so that the I-shaped laminate iron core is pressed by the inner surfaces of the tapered surfaces of the pair of C-shaped iron cores. The iron cores used for the coil component are stamped by a process of positioning the C-shaped cores in opposition to each other perpendicular to the hoop width, shifting one of the C-shaped cores perpendicular to the hoop width, obliquely positioning the I-shaped core between the C-shaped cores and then successively stamping the iron core hoop.

Abstract: A negative electrode material for use in lithium-ion secondary batteries, comprising milled pitch-based graphite fibers (A) obtained by graphitization at 2400.degree. C. or higher and milled pitch-based carbon fibers (B) obtained by carbonization at 550.degree. to 1300.degree. C. In this negative electrode material, it is preferred that both the milled pitch-based graphite fibers (A) and the milled pitch-based carbon fibers (B) have an average particle size of 10 to 30 .mu.m, that the ratio of milled pitch-based carbon and graphite fibers having a particle size of 5 .mu.m or less to all the milled pitch-based carbon and graphite fibers is not greater than 10% by weight and that the milled pitch-based graphite fibers (A) and the milled pitch-based carbon fibers (B) are blended at a weight ratio (A/B) of 95/5 to 40/60.

Abstract: A carbon material for use in a lithium secondary battery, which is obtained by graphitization conducted in the presence of a boric compound so as to contain boron in an amount ranging from 1,000 ppm to 30,000 ppm and which, when subjected to X-ray diffractometry, exhibits an interplanar spacing of 002 surface (d.sub.002) of not greater than 0.338 nm, a crystallite size along c-axis (Lc) of at least 35 nm, a crystallite size along a-axis (La) of at least 50 nm and a ratio of diffraction peak (101) to diffraction peak (100), designated as P.sub.101 /P.sub.100, of at least 1.0; a negative electrode and a lithium secondary battery each produced by using the above carbon material; and a process for producing the carbon material. This carbon material exhibits large charge and discharge capacities, so that it can provide a negative electrode for use in a lithium secondary battery which is excellent in charge and discharge cycle characteristics.

Abstract: A negative electrode for use in a secondary battery is disclosed, comprising milled carbon fibers derived from mesophase pitch wherein the milled carbon fibers each has a fiber cut surface and a fiber axis intersecting with each other at cross angles, the smaller one thereof being at least 65.degree. on the average. This negative electrode does not suffer from property deterioration, irrespective of multiple repetitions of charge and discharge, from which a nonaqueous-electrolyte-loaded lithic secondary battery having excellent cycle characteristics can be fabricated.

Abstract: The mesophase pitch based and melt blown discontinuous carbon fibers of a peculiar structure are provided. These fibers are characterized in that a large number of small domains, each domain has an average equivalent diameter of from 0.03 .mu.m to 1 .mu.m and has a nearly unidirectional orientation of folded carbon layers, assemble to form a mosaic structure on the cross-section of the said carbon fibers and that the folded carbon layers of each domain are oriented at an angle to the direction of the folded carbon layers of the neighboring domains on the boundary.

Abstract: A process for providing activated carbon fibers consisting of optically anisotropic components and optically isotropic components by spinning a pitch into fibers, and infusibilizing the resulting fibers, followed by an activation treatment. The pitch for spinning is prepared by melt mixing together (A) 100 parts by weight of an optically isotropic pitch having a softening point of 230.degree.-300.degree. C. obtained by heat treatment of a pitch while blowing an oxygen containing gas into the pitch, and (B) 10-50 parts by weight of an optically isotropic pitch having a softening point of 200.degree.-270.degree. C. obtained by polymerization of naphthalene in the presence of a Lewis acid catalyst. The optically isotropic pitch (B) is further characterized as having the property of being converted into an optically anisotropic pitch by the stress occurring at the time of spinning.

Abstract: The disclosed carbon fiber felting material has a bulk density of 0.01 to 0.5 g/cm.sup.3 and a thermal conductivity of at most 1.0 kcal/m.multidot.hr.multidot..degree.C. in the thickness-wise direction thereof at 2,200.degree. C. The carbon fiber felting material is formed through physical and/or chemical interfiber entanglement. The carbon fiber felting material is very stable in an inert atmosphere, and excellent in heat insulating properties in a high-temperature range and against radiant heat transfer in particular.

Abstract: There is disclosed a process for continuously producing a pitch-based carbon fiber felt which comprises the steps of spinning a pitch by melt blow spinning system; accumulating the spun fibers as a pitch fiber web composed of the aggregate of short fibers; continuously cross lapping the web; subsequently stabilizing the cross lapped web; carbonizing and/or activating the stabilized web; and then felting the resultant web. The above-mentioned process is capable of efficiently producing a pitch-based carbon fiber felt having uniform unit weight and excellent physical properties and well suited for use in high-performance thermal insulator, cushioning thermal insulator, filter media and adsorbent for water purification and solvent recovery, etc.

Abstract: An infusiblized, or infusiblized and slightly carbonized fiber of optically anisotropic pitch type is combined with a phenolic resin fiber to produce a high bulk density carbon fiber structure in the form of a laminate of mutually entangled carbon fiber sheets with improved handleability of fiber sheets and improved stability of a laminate structure formed through entanglement. A high flexural strength carbon-carbon composite material with a high volume fiber content is produced by impregnation with a precursor of carbon and subsequent carbonization of the carbon fiber structure of the kind as described above or a fiber laminate of mutually entangled sheets of the infusiblized, or infusiblized and slightly carbonized fiber of optically anisotropic pitch type blended with the phenolic resin fiber.

Abstract: Flexible materials for reflecting electromagnetic waves can be provided by using adhesive type non-woven fabrics formed by self adhesion of the principal component of pitch based carbon fibers.

Abstract: A screw compressor which a casing defining therein a pair of cylindrical chambers axially intersected, and a pair of male and female screws in an intermeshing relationship. The casing includes an inlet port having a profile composed of an open area fully open to the chambers and the remaining solid area occupied with one portions of shafts of the screws and with one portion of the casing, said profile being equal to a profile of the chambers, such that the fluid can flow freely into the chambers without causing turbulent fluid flow.

Abstract: A method for preventing a leakage loss of gases in an oil-free screw type rotary compressor including a housing, a rotor assembly comprising a pair of male and female rotor members rotatably mounted within said housing and a cooling jacket surrounding said housing, said housing and said pair of male and female rotor members defining therebetween an axially progressive series of sealed cavities for a gas, which method comprises the steps of returning as cooled a leakage gas from rotor shaft seals on the discharge side of said compressor to a first of said axially progressive series of sealed cavities, the leakage gas being returned to the compressor at a point where the suction cycle has been completed and the compression cycle has yet to begin.