A process for preparing stacks of metal chalcogenide flakes includes: (a) reacting together a source of the metal atom of the target metal chalcogenide with a source of the chalcogenide atom of the target metal chalcogenide, in the presence of a spacer, so as to produce flakes of the metal chalcogenide; (b) depositing metal chalcogenide flakes obtained using step (a) onto a substrate to form a stack of assembled metal chalcogenide flakes, wherein the spacer contains an alkyl chain linked to a functional group able to bond to the metal chalcogenide surface, said alkyl chain having a length of less than 18 carbon atoms, preferably between 6 and 14 carbon atoms.

A porous plate-shaped filler of the present invention is a plate shape having an aspect ratio of 3 or more, a surface shape is one of a round shape, an oval and a round-corner polygonal shape, and its minimum length is from 0.1 to 50 m. Furthermore, a sectional shape is one of an arch shape, an elliptic shape, and a quadrangular shape in which at least a part of corners is rounded. Consequently, it is possible to obtain the heat insulation film in which the porous plate-shaped fillers 1 are easy to be laminated and the heat insulation effect improves.

The porous plate-shaped filler aggregate includes a plurality of the porous plate-shaped fillers. The porous plate-shaped fillers have a uniform plate shape with an aspect ratio of 3 or more, a minimum length of 0.1 to 50 m, a porosity of 20 to 99%, and the deviation of the maximum length among a plurality of the porous plate-shaped fillers, which is obtained by the following formula, is 10% or less.
Deviation of the maximum length (%)=standard deviation of the maximum length/average value of the maximum length100 (Here, maximum length is the longest length when the porous plate-shaped fillers are held between a pair of parallel planes.)

In a heat-insulation film, porous plate fillers are dispersed in a matrix to bond the porous plate fillers. The porous plate filler includes plates having an aspect ratio of 3 or more, a minimum length of 0.1 to 50 m and a porosity of 20 to 90%. In the heat-insulation film, a volume ratio between the porous plate fillers and the matrix is from 50:50 to 95:5. In the heat-insulation film in which the porous plate fillers are used, a length of a heat transfer path increases and a thermal conductivity can be decreased, as compared with a case where spherical or cubic fillers are used.

The present invention is a surface-modified carbon material including chemical addends added to the surface of graphene, such that a one-dimensional periodicity corresponding to a large number of addition positions of the chemical addends can be observed in a Fourier-transformed image of a scanning probe microscopic image of the surface of graphene. The surface-modified carbon material of the present invention has a bandgap and therefore can be used as a sensor capable of electronically controlling an operation or another electronic device.

The present invention relates to a method of producing graphene and/or graphene oxide. The method comprises providing a copper-based sheet coated on one side with a carbonaceous material; providing a bath comprising an aqueous solution comprising a salt of at least one ion selected from Li.sup.+, Na.sup.+, K+, Mg.sup.2+ or Ca.sup.2+, in which bath a first electrode is arranged; feeding the copper-based sheet into the bath; applying a first voltage between the copper-based sheet and the first electrode; applying a second voltage, reversed as compared to the first voltage, between the copper-based sheet and the first electrode, such that graphene and/or graphene oxide is exfoliated from the carbonaceous material. The present invention also relates to a system for producing graphene and/or graphene oxide. The present invention also relates to a graphene material formed as crystalline, self-supporting hexagonal flakes. The present invention also relates to a graphene material formed as crystalline, self-supporting flakes comprising dendrites.

The invention provides a plurality of substantially same planar pigment flakes, each formed of one or more thin film layers. Each flake has a face surface and a flake border delimiting the face surface; the flake border undulates in the plane of the flake. The flakes have a pre-selected shape, may have a symbol or a grating thereon. A method of manufacturing of these flakes including the steps of: (a) providing a substrate having a plurality of one-flake regions and a plurality of depressions or protrusions disposed therebetween and not extending into the one-flake regions, (b) coating the substrate with a releasable coating, and (c) removing the releasable coating and breaking it into the flakes; wherein two adjacent of the one-flake regions are separated by at least three of the depressions or protrusions for facilitating the breaking of the releasable coating into the flakes.

96 parts by mass of a -alumina powder, 4 parts by mass of a an AlF.sub.3 powder, and 0.17 parts by mass of an -alumina powder as a seed crystal were mixed by a pot mill. The purities of each raw material were evaluated, and it was found that the mass ratio of each impurity element other than Al, O, F, H, C, and S was 10 ppm or less. In a high-purity alumina-made sagger having a purity of 99.9 percent by mass, 300 g of the obtained mixed powder was received, and after a high-purity alumina-made lid having a purity of 99.9 percent by mass was placed on the sagger, a heat treatment was perforated at 900 C. for 3 hours in an electric furnace in an air flow atmosphere, so that an alumina powder was obtained. The value of AlF.sub.3 mass/container volume was 0.016 g/cm.sup.3.

A microstructure comprises a plurality of interconnected units wherein the units are formed of hexagonal boron nitride (h-BN) tubes. The graphene tubes may be formed by photo-initiating the polymerization of a monomer in a pattern of interconnected units to form a polymer microlattice, removing unpolymerized monomer, coating the polymer microlattice with a metal, removing the polymer microlattice to leave a metal microlattice, depositing an h-BN precursor on the metal microlattice, converting the h-BN precursor to h-BN, and removing the metal microlattice.

An alumina sintered body according to the present invention includes a surface having a degree of c-plane orientation of 5% or more, the degree of c-plane orientation being determined by a Lotgering method using an X-ray diffraction profile obtained through X-ray irradiation at 2=20 to 70. The alumina sintered body contains Mg and F, a Mg/F mass ratio is 0.05 to 3500, and a Mg content is 30 to 3500 ppm by mass. The alumina sintered body has a crystal grain size of 15 to 200 m. When a field of view of 370.0 m long372.0 m wide is photographed with a 1000-fold magnification and the photograph is visually observed, a number of pores having a diameter of 0.2 to 0.6 m is 250 or less.