Abstract: A dispersion of carbon nanoparticles is prepared by monodispersing carbon nanoparticles in water droplets of a reverse micelle solution in which the water droplets are coated with amphiphilic molecules and dispersed in an organic solvent. In a method of preparing the dispersion of carbon nanoparticles, carbon nanoparticles and a monodispersion function material, e.g., ammonia, for imparting a polarity to surfaces of the carbon nanoparticles are added to the reverse micelle solution. The solution is then stirred, so that the carbon nanoparticles whose surfaces have the polarity are monodispersed in the water droplets of the reverse micelle solution. Further, a metal alkoxide is added to the solution and then stirring them, so that the surfaces of the carbon nanoparticles are coated with oxide of the metal.

Abstract: A method for manufacturing an electron emitting device includes disposing a cathode substrate and an anode substrate to be faced to each other in a depressurized atmosphere containing an activation gas, the cathode substrate including a carbon layer formed by applying a paste having a fibrous carbon and carbon impurities on a cathode conductor and drying the coated paste. The method further includes applying a reverse bias voltage to the cathode conductor of the cathode substrate and an anode conductor of the anode substrate, thereby activating the carbon layer.

Abstract: A dispersion of carbon nanoparticles is prepared by monodispersing carbon nanoparticles in water droplets of a reverse micelle solution in which the water droplets are coated with amphiphilic molecules and dispersed in an organic solvent. In a method of preparing the dispersion of carbon nanoparticles, carbon nanoparticles and a monodispersion function material, e.g., ammonia, for imparting a polarity to surfaces of the carbon nanoparticles are added to the reverse micelle solution. The solution is then stirred, so that the carbon nanoparticles whose surfaces have the polarity are monodispersed in the water droplets of the reverse micelle solution. Further, a metal alkoxide is added to the solution and then stirring them, so that the surfaces of the carbon nanoparticles are coated with oxide of the metal.

Abstract: Ultradispersed ones of primary particles of nanometer-sized carbon are obtained by applying a wet-type milling method and/or a wet dispersion method to an aggregate structure of the primary particles to overcome van der Waals forces, by which forces the primary particles are held together to form the aggregate structure, whereby the ultradispersed primary particles are obtained in a colloidal dispersion on a large-scale basis at low cost without using any additive. In a method of manufacturing the ultradispersed primary particles, the wet-type milling method is carried out in a ball mill, preferably in combination with a high-energy ultrasonic-wave process carried out in a dispersing medium such as pure water, whereby a colloidal solution or slurry with a low-concentration of the primary particles ultradispersed in the dispersing medium is obtained.

Abstract: Ultradispersed ones of primary particles of nanometer-sized carbon are obtained by applying a wet-type milling method and/or a wet dispersion method to an aggregate structure of the primary particles to overcome van der Waals forces, by which forces the primary particles are held together to form the aggregate structure, whereby the ultradispersed primary particles are obtained in a colloidal dispersion on a large-scale basis at low cost without using any additive. In a method of manufacturing the ultradispersed primary particles, the wet-type milling method is carried out in a ball mill, preferably in combination with a high-energy ultrasonic-wave process carried out in a dispersing medium such as pure water, whereby a colloidal solution or slurry with a low-concentration of the primary particles ultradispersed in the dispersing medium is obtained.

Abstract: The present invention provides a phosphor of formula A2SiO5:B (A is Y or Gd, and B is Ce or Tb) which is characterized by a surface elemental composition represented by (A+B)/Si ranging from 1.5 to 2.5, wherein A is Y or Gd, and B is Ce or Tb; and method for preparing said phosphor. One embodiment of the method is as follows: a SiO2 powder is mixed with co-precipitate (Y, Ce)2O3 (Ce/Y=0.01), in an amount ranging from 10 to 110 mol % based on the amount of (Y, Ce)2O3, and the mixture is charged into the inner crucible of a double-walled aluminum crucible. After graphite is charged between the inner and outer crucible, the mixture is calcined at 1450° C. for 2 hours to obtain an Y2SiO5:Ce phosphor. The luminous efficiency of a field emission display (FED) prepared employing the Y2SiO5:Ce phosphor was measured at an anode voltage of 600V, an electric power input of 30 Wp-p and a duty rate of 1/240.

Abstract: A method for preparing a gallium nitride phosphor which is capable of emitting light at luminance increased to a degree sufficient to permit the phosphor to be practically used. A dopant compound containing elements reacted with H2 and gasified by heating is arranged on an upstream side in a calcination oven in which NH3 is flowed and a matrix element compound is arranged on the downstream side therein, resulting in calcination of the compound being carried out. This permits GaN to be surrounded with ammonia and the dopant during the calcination, so that the GaN phosphor may be fully doped with the dopant.

Abstract: The present invention provides a phosphor of formula A2SiO5:B (A is Y or Gd, and B is Ce or Tb) which is characterized by a surface elemental composition represented by (A+B)/Si ranging from 1.5 to 2.5, wherein A is Y or Gd, and B is Ce or Tb; and method for preparing said phosphor. One embodiment of the method is as follows: a SiO2 powder is mixed with co-precipitate (Y, Ce)2O3 (Ce/Y=0.01), in an amount ranging from 10 to 110 mol % based on the amount of (Y, Ce)2O3, and the mixture is charged into the inner crucible of a double-walled aluminum crucible. After graphite is charged between the inner and outer crucible, the mixture is calcined at 1450° C. for 2 hours to obtain an Y2SiO5:Ce phosphor. The luminous efficiency of a field emission display (FED) prepared employing the Y2SiO5:Ce phosphor was measured at an anode voltage of 600V, an electric power input of 30 Wp-p and a duty rate of 1/240.

Abstract: A ZnO phosphor of a red luminous color capable of being increased in luminous efficiency. A the Zn3.5Y0.92Eu0.08O5 phosphor which is an example of the present invention is manufactured by immersing 117 mmol of ZnO:Zn in an aqueous solution in which 1.84 mmol of YCl3 and 0.16 mmol of EuCl3 are dissolved. Excessive water is vaporized by heating the solution to a temperature of 300° C. This results in pink porous blocks being obtained, which are then placed in a crucible. The crucible is heated at 100° C. for two hours, so that a white powder of a red luminous color is obtained. The powder has main peaks at 612 nm and 702 nm. A luminous spectra of the phosphor indicates that it exhibits enhanced luminous efficiency.

Abstract: A fluorescent material and a display device incorporating the fluorescent material are described. The fluorescent material is a mixture including a phosphor which is excitable at a voltage of 1 kV or higher for emitting light and a phosphor which is excitable at a voltage of 1 kV or lower for emitting light, wherein each phosphor emits light of the same color and the fluorescent material is luminous at an anode voltage of 2 kV or lower. The fluorescent display device accelerates electrons emitted from an electron source at an anode voltage of 2 kV or lower and rushes these electrons against an anode for exciting the fluorescent material present on the anode. The fluorescent material is a mixture as set forth above.

Abstract: A phosphor capable of being kept from being affected by oxygen during production thereof, carrying out luminescence due to excitation by electrons, selectively realizing various luminous colors depending on selection of starting materials and exhibiting satisfactory luminance and life characteristics. The phosphor is represented by a chemical formula Ga.sub.1-x In.sub.x N:A (0.ltoreq.x<0.8, A.dbd.Zn or Mg) and prepared by mixing starting materials containing at least an oxygen-free gallium compound and an oxygen-free doping substance to prepare a mixture and heating the mixture in a nitrogen-containing atmosphere.

Abstract: A low-velocity electron excited phosphor having a composition represented by a general formula ZnO.multidot.(Al.sub.x, Ga.sub.1-x).sub.2 O.sub.3 :Mn, wherein X=0.001 to 0.3 mol. A content of Al in the phosphor is set be to within a range between 0.001 mol and 0.3 mol. The range permits a variation in luminance of the phosphor to be within .+-.30% and initial luminance of the phosphor to be significantly increased, resulting in the phosphor being suitable for use for a fluorescent display device.

Abstract: A phosphor is disclosed which is suitable for use for a fluorescent display device and driven at a driving voltage as low as 1 kV or less and free of S and Cd. Compounds of Ti, alkaline earth metal and an element of Group 13 of the periodic table in predetermined amounts are heated at 1100.degree. to 1400.degree. C. for calcination, resulting in a solid solution of the rare earth element and one element of Group 13 being formed in a phosphor matrix made of an oxide of alkaline earth metal and Ti. An example of the phosphor is SrTiO.sub.3 :Pr,Al exhibiting a red luminous color.

Abstract: A low-velocity electron excited phosphor having a composition represented by a general formula ZnO.multidot.(Al.sub.x, Ga.sub.l-x).sub.2 O.sub.3 :Mn, wherein X=0.001 to 0.3 mol. A content of Al in the phosphor is set be to within a range between 0.001 mol and 0.3 mol. The range permits a variation in luminance of the phosphor to be within .+-.30% and initial luminance of the phosphor to be significantly increased, resulting in the phosphor being suitable for use for a fluorescent display device.