A product includes an aerogel having a single bulk structure, the single bulk structure having at least one dimension greater than 10 millimeters. The single bulk structure includes a plurality of pores, where each pore has a largest diameter defined as a greatest distance between pore walls of the respective pore. In addition, an average of the largest diameters of a majority of the pores is within a specified range, and the plurality of pores are distributed substantially homogenously throughout the single bulk structure.

A product includes an aerogel having a single bulk structure, the single bulk structure having at least one dimension greater than 10 millimeters. The single bulk structure includes a plurality of pores, where each pore has a largest diameter defined as a greatest distance between pore walls of the respective pore. In addition, an average of the largest diameters of a majority of the pores is within a specified range, and the plurality of pores are distributed substantially homogenously throughout the single bulk structure.

A process for manufacturing pyrocarbon, includes forming pyrocarbon by a calefaction process from at least one C.sub.2 to C.sub.6 alcohol or polyalcohol precursor, the precursor being ethanol, rough laminar pyrocarbon being obtained by imposing a temperature of between 1250° C. and 1325° C. during calefaction.

A method for producing a body obtained by processing a solid carbon-containing material, the method includes: preparing the solid carbon-containing material composed of a material having at least a surface containing solid carbon; forming a gas phase fluid containing at least one of an active gas or an active plasma which are active against the solid carbon; and processing the solid carbon-containing material by injecting the gas phase fluid onto at least a part of the surface of the solid carbon-containing material.

A method for producing a body obtained by processing a solid carbon-containing material, the method includes: preparing the solid carbon-containing material composed of a material having at least a surface containing solid carbon; forming a gas phase fluid containing at least one of an active gas or an active plasma which are active against the solid carbon; and processing the solid carbon-containing material by injecting the gas phase fluid onto at least a part of the surface of the solid carbon-containing material.

Bearing assemblies that include a plurality of polycrystalline diamond (“PCD”) bearing elements, bearing apparatuses including such bearing assemblies, and methods of operating and fabricating such bearing assemblies and apparatuses are disclosed. In an embodiment, the plurality of PCD bearing elements of one or more of the bearing assemblies disclosed herein include at least one first PCD bearing element. At least a portion of the first PCD bearing element exhibits a coercivity of about 125 Oersteds or more and a specific magnetic saturation of about 14 Gauss.Math.cm.sup.3/gram or less. The first PCD bearing element includes a bearing surface with at least one groove formed therein. In an embodiment, the plurality of PCD bearing elements also include at least one second PCD bearing element. The second PCD bearing element exhibits a coercivity that is less than and a specific magnetic saturation that is greater than the first PCD bearing element.

The present invention relates to a negative active material for a lithium secondary battery, a preparation method therefor, and a lithium secondary battery including the same. The negative electrode active material is a negative electrode material for a secondary battery, the negative electrode active material comprising a silicon-carbon composite comprising: a core comprising crystalline carbon and silicon particles; and an amorphous carbon-containing coating layer disposed on a surface of the core, wherein the negative electrode active material comprises: silicon oxide formed on a surface of the silicon particles; and an oxide of crystalline carbon, formed on a surface of the crystalline carbon, the average particle diameter (D50) of the silicon particles having a nanometer size, the proportion of O relative to Si in the silicon oxide is 30%-50%, and the proportion of O relative to C in the oxide of the crystalline carbon is 4%-10%.

The present invention relates to a negative active material for a lithium secondary battery, a preparation method therefor, and a lithium secondary battery including the same. The negative electrode active material is a negative electrode material for a secondary battery, the negative electrode active material comprising a silicon-carbon composite comprising: a core comprising crystalline carbon and silicon particles; and an amorphous carbon-containing coating layer disposed on a surface of the core, wherein the negative electrode active material comprises: silicon oxide formed on a surface of the silicon particles; and an oxide of crystalline carbon, formed on a surface of the crystalline carbon, the average particle diameter (D50) of the silicon particles having a nanometer size, the proportion of O relative to Si in the silicon oxide is 30%-50%, and the proportion of O relative to C in the oxide of the crystalline carbon is 4%-10%.

Disclosed herein are a polyimide film for graphite sheets and a graphite sheet manufactured using the same. The polyimide film is fabricated by imidizing a precursor composition including: a polyamic acid prepared by reacting a dianhydride monomer with a diamine monomer; and an organic solvent, wherein the diamine monomer includes about 30 mol % to about 70 mol % of 4,4′-methylenedianiline and about 30 mol % to about 70 mol % of 4,4′-oxydianiline based on the total number of moles of the diamine monomer, 4,4′-methylenedianiline and 4,4′-oxydianiline being present in total in an amount of about 85 mol % or more based on the total number of moles of the diamine monomer.

Disclosed herein are a polyimide film for graphite sheets and a graphite sheet manufactured using the same. The polyimide film is fabricated by imidizing a precursor composition including: a polyamic acid prepared by reacting a dianhydride monomer with a diamine monomer; and an organic solvent, wherein the diamine monomer includes about 30 mol % to about 70 mol % of 4,4′-methylenedianiline and about 30 mol % to about 70 mol % of 4,4′-oxydianiline based on the total number of moles of the diamine monomer, 4,4′-methylenedianiline and 4,4′-oxydianiline being present in total in an amount of about 85 mol % or more based on the total number of moles of the diamine monomer.