Provided is a surface-modified nanodiamond that has high dispersibility in an organic solvent or in a resin and that can maintain the characteristics described above even in a high-temperature environment of 200° C. or higher. The surface-modified nanodiamond according to an embodiment of the present invention has a structure in which a surface of a nanodiamond particle is modified by a group represented by Formula (1) below. In the formula, R.sup.1 to R.sup.4 are the same or different and each represent an aliphatic hydrocarbon group having from 1 to 25 carbons. Note that at least one of R.sup.1 to R.sup.4 is an aliphatic hydrocarbon group having from 10 to 25 carbons. Furthermore, an atomic bond of the carbon atom in the formula bonds to the surface of the nanodiamond particle.

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Provided is a surface-modified nanodiamond that has high dispersibility in an organic solvent or in a resin and that can maintain the characteristics described above even in a high-temperature environment of 200° C. or higher. The surface-modified nanodiamond according to an embodiment of the present invention has a structure in which a surface of a nanodiamond particle is modified by a group represented by Formula (1) below. In the formula, R.sup.1 to R.sup.4 are the same or different and each represent an aliphatic hydrocarbon group having from 1 to 25 carbons. Note that at least one of R.sup.1 to R.sup.4 is an aliphatic hydrocarbon group having from 10 to 25 carbons. Furthermore, an atomic bond of the carbon atom in the formula bonds to the surface of the nanodiamond particle.

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An embodiment provides a method for modifying a carbon region on a boron-doped diamond electrode surface, comprising: placing a boron-doped diamond electrode surface in an aqueous solution, wherein the aqueous solution comprises an ionic treatment solution; applying a voltage difference across the boron-doped diamond electrode surface; and modifying a carbon region on an area of the boron-doped diamond electrode surface, wherein the modifying is responsive to application of the voltage while the boron-doped diamond electrode surface is in the aqueous solution, wherein the modification continues until a desired signal of the carbon region is reached. Other aspects are described and claimed.

An embodiment provides a method for modifying a carbon region on a boron-doped diamond electrode surface, comprising: placing a boron-doped diamond electrode surface in an aqueous solution, wherein the aqueous solution comprises an ionic treatment solution; applying a voltage difference across the boron-doped diamond electrode surface; and modifying a carbon region on an area of the boron-doped diamond electrode surface, wherein the modifying is responsive to application of the voltage while the boron-doped diamond electrode surface is in the aqueous solution, wherein the modification continues until a desired signal of the carbon region is reached. Other aspects are described and claimed.

A cross-linked structure of a carbon material is excellent in mechanical strength, such as tensile strength. The carbon materials such as carbon nanotube, graphite, fullerene, and carbon nanocoil, are cross-linked with each other. The carbon materials are cross-linked through a linking group derived from a nucleophilic compound having two or more nucleophilic groups in the molecule.

A cross-linked structure of a carbon material is excellent in mechanical strength, such as tensile strength. The carbon materials such as carbon nanotube, graphite, fullerene, and carbon nanocoil, are cross-linked with each other. The carbon materials are cross-linked through a linking group derived from a nucleophilic compound having two or more nucleophilic groups in the molecule.

The invention relates to methods for creating and detecting images inside diamonds that carry information for various purposes, for example, an identification code, marks identifying diamonds. A method for creating an optically permeable image inside a diamond is disclosed, in which image consists of a given set of optically permeable elements of micron or submicron size, which elements are disturbances in the periodicity of the diamond crystal structure. The image created in the diamond is a mark consisting of the given set of optically permeable elements of micron or submicron size. The elements are disturbances in the periodicity of the diamond crystal structure with the participation of chemical elements of impurities formed at vacancies and interstitials in the volume of micron or submicron size. Methods and systems for detecting optically permeable images inside diamonds are also disclosed.

The invention relates to methods for creating and detecting images inside diamonds that carry information for various purposes, for example, an identification code, marks identifying diamonds. A method for creating an optically permeable image inside a diamond is disclosed, in which image consists of a given set of optically permeable elements of micron or submicron size, which elements are disturbances in the periodicity of the diamond crystal structure. The image created in the diamond is a mark consisting of the given set of optically permeable elements of micron or submicron size. The elements are disturbances in the periodicity of the diamond crystal structure with the participation of chemical elements of impurities formed at vacancies and interstitials in the volume of micron or submicron size. Methods and systems for detecting optically permeable images inside diamonds are also disclosed.

In an embodiment, a polycrystalline diamond table includes a plurality of bonded diamond grains and a plurality of interstitial regions defined by the plurality of bonded diamond grains. The polycrystalline diamond table may be at least partially leached such that at least a portion of at least one interstitial constituent has been removed from at least a portion of the plurality of interstitial regions by exposure to a leaching agent. The leaching agent may include a mixture having a ratio of weight % hydrofluoric acid to weight % nitric acid of about 1.0 to about 2.4, and water in a concentration of about 50 weight % to about 85 weight %. Various other materials, articles, and methods are also disclosed.

In an embodiment, a polycrystalline diamond table includes a plurality of bonded diamond grains and a plurality of interstitial regions defined by the plurality of bonded diamond grains. The polycrystalline diamond table may be at least partially leached such that at least a portion of at least one interstitial constituent has been removed from at least a portion of the plurality of interstitial regions by exposure to a leaching agent. The leaching agent may include a mixture having a ratio of weight % hydrofluoric acid to weight % nitric acid of about 1.0 to about 2.4, and water in a concentration of about 50 weight % to about 85 weight %. Various other materials, articles, and methods are also disclosed.