Abstract: A fine carbon fiber having an outer diameter of about 1 to about 80 nm and an aspect ratio of 10 to 30,000, comprising a hollow center portion and a multi-layer sheath structure of a plurality of carbon layers, the layers forming annual rings, wherein the sheath-forming carbon layers form an incomplete sheath, i.e., the carbon layers are partially broken or disrupted in a longitudinal direction, and the outer diameter of the carbon fiber and/or the diameter of the hollow center portion are not uniform in a longitudinal direction. The carbon fiber is obtained by instantaneously reacting a carrier gas at a high temperature and an organic compound gas kept at a temperature below the decomposition temperature of the transition metal compound and has a conductivity equivalent to that of a conventional vapor phase method and is useful as a filler material in resins, rubbers, paints and the like.

Abstract: A fine carbon fiber having an outer diameter of about 1 to about 80 nm and an aspect ratio of 10 to 30,000, comprising a hollow center portion and a multi-layer sheath structure of a plurality of carbon layers, the layers forming annual rings, wherein the sheath-forming carbon layers form an incomplete sheath, i.e., the carbon layers are partially broken or disrupted in a longitudinal direction, and the outer diameter of the carbon fiber and/or the diameter of the hollow center portion are not uniform in a longitudinal direction. The carbon fiber is obtained by instantaneously reacting a carrier gas at a high temperature and an organic compound gas kept at a temperature below the decomposition temperature of the transition metal compound and has a conductivity equivalent to that of a conventional vapor phase method and is useful as a filler material in resins, rubbers, paints and the like.

Abstract: A process for the isolation of carbon nanotubes from a mixture containing carbon nanotubes and graphite is disclosed, which includes the steps of:(a) reacting the mixture with a metal compound to intercalate the metal compound into the graphite;(b) reducing the reaction mixture obtained in step (a) to convert the intercalated metal compound to elemental metal;(c) heating the reduction mixture obtained in step (b) at a temperature of 450-600.degree. C. in an oxygen-containing atmosphere to selectively oxidize the graphite and the elemental metal; and(d) contacting the heated mixture obtained in step (c) with a liquid to dissolve the oxidized metal in the liquid and to separate the carbon nanotubes as a solid phase from the oxidized metal.

Abstract: Soot containing fullerenes is produced by impressing a DC voltage between a carbonaceous anode and a cathode in an airtight chamber maintained in an inert gas atmosphere to cause arc discharge to occur. After termination of the impression of the DC voltage, an inert gas is blown into the chamber to fluidize the soot. The fluidized soot is discharged from the chamber and is brought into contact with a solvent to recover the fullerenes.

Abstract: Carbon nanotubes are isolated from a mixture containing the carbon nanotubes and graphite particles by a process including the steps of:finely pulverizing the mixture;dispersing the pulverized product in a liquid medium;centrifuging the resulting dispersion to obtain a supernatant containing carbon nanotubes and graphite particles having a particle size of 0.3 .mu.m or less;separating the supernatant into a solid phase and a liquid phase; andcalcining the solid phase in an oxygen-containing atmosphere at a temperature sufficient to burn the graphite particles and to leave the nanotubes.

Abstract: Carbon nanotubes are produced by successively repositioning an axially extending rod-like carbonaceous anode relative to a cathode surface such that a tip end surface of the anode successively faces on different portions of the cathode surface while impressing a direct current voltage therebetween, so that an arc discharge occur with the simultaneous formation of carbonaceous deposits containing carbon nanotubes on each of the portions of the cathode surface. The carbonaceous deposits are scraped and collected. A device for carrying out the above method includes a driving member for displacing the cathode surface relative to the anode.

Abstract: A cephalosporin compound of the formula: ##STR1## wherein R.sup.1 is hydrogen or lower alkyl;R.sup.2 is acetoxy or (1-methyl-1H-tetrazol-5-yl)thio, andR.sup.3 is carboxy; orR.sup.2 is a group of the formula: ##STR2## R.sup.3 is --COO.sup.- and Y is hydrogen, hydroxymethyl or carbamoyl; andn is an integer of 2 or 3,or a pharmaceutically acceptable salt thereof and processes for their preparation are disclosed. Said cephalosporin compound is useful as an antimicrobial agent.

Abstract: A cephalosporin compound of the formula: ##STR1## wherein R.sup.1 is hydrogen or lower alkyl;R.sup.2 is acetoxy or (1-methyl-1H-tetrazol-5-yl)thio, andR.sup.3 is carboxy; orR.sup.2 is a group of the formula: ##STR2## R.sup.3 is --COO.sup.- and Y is hydrogen, hydroxymethyl or carbamoyl; andn is an integer of 2 or 3,or a pharmaceutically acceptable salt thereof and processes for their preparation are disclosed. Said cephalosporin compound is useful as an antimicrobial agent.

Abstract: A cephalosporin compound of the formula: ##STR1## wherein R.sup.1 is hydrogen or lower alkyl;R.sup.2 is acetoxy or (1-methyl-1H-tetrazol-5-yl)thio, andR.sup.3 is carboxy; orR.sup.2 is a group of the formula ##STR2## R.sup.3 is --COO.sup.- and Y is hydrogen, hydroxymethyl or carbamoyl; andn is an integer of 2 or 3,or a pharmaceutically acceptable salt thereof and processes for their preparation are disclosed. Said cephalosporin compound is useful as an antimicrobial agent.

Abstract: A cephalosporin compound of the formula: ##STR1## wherein R.sup.1 is hydrogen or lower alkyl;R.sup.2 is acetoxy or (1-methyl-1H-tetrazol-5-yl)thio, andR.sup.3 is carboxy; orR.sup.2 is a group of the formula: ##STR2## R.sup.3 is --COO.sup.- and Y is hydrogen, hydroxymethyl or carbamoyl; andn is an integer of 2 or 3,or a pharmaceutically acceptable salt thereof and processes for their preparation are disclosed. Said cephalosporin compound is useful as an antimicrobial agent.

Abstract: A cephalosporin compound of the formula: ##STR1## wherein R.sup.1 is a hydrogen atom, a lower alkyl group, a carboxy(lower)alkyl group, a hydroxy(lower)alkyl group, a carbamoyl(lower)alkyl group, an N-(lower)alkyl-carbamoyl(lower)alkyl group, a cycloalkyl group, a carboxycycloalkyl group, or a tetrazolylmethyl group, R.sup.2 is a hydrogen atom, a lower alkyl group, a formyl group or a lower alkanol group, R.sup.3 is a hydrogen atom, or R.sup.2 and R.sup.3 are combined together to form an aralkylidene group, or a pharmaceutically acceptable salt thereof which is useful as an antimicrobial agent, and process for their preparation.

Abstract: A 7.beta.-{(Z)-2-(2-aminothiazol-4-yl)-2-[(2-pyrrolidon-3-yl)oxyimino]acetam ido}-3-(1-amino-1H-tetrazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid or a pharmaceutically acceptable salt thereof is useful as an antimicrobial agent.

Abstract: A quinoline compound of the formula: ##STR1## wherein R.sup.1 is hydrogen or fluorine. A method of preparing the compound (I) is disclosed. The compound (I) and a pharmaceutically acceptable salt thereof are useful as antimicrobial agents.

Abstract: A compound of the formula: ##STR1## wherein R.sup.1 is hydrogen or hydroxy, R.sup.2 is a group of the formula: --CO-CH(NH.sub.2)-CH.sub.2 COR.sup.3 or --COCH.sub.2 -CH(NH.sub.2)-COR.sup.3, and R.sup.3 is selected from the group consisting of hydroxy, lower alkylamino, di-lower alkylamino, lower alkoxy and hydroxy-lower alkylamino, or R.sup.3 is amino when R.sup.2 is hydroxy. Several methods of preparing the compound [I] are also disclosed. The compound [I] and a pharmaceutically acceptable salt thereof are useful as antimicrobial agents.