Three-dimensional nanoporous aerogels and suitable preparation methods are provided. Nanoporous aerogels may include a carbide material such as a silicon carbide, a metal carbide, or a metalloid carbide. Elemental (e.g., metallic or metalloid) aerogels may also be produced. In some embodiments, a cross-linked aerogel having a conformal coating on a sol-gel material is processed to form a carbide aerogel, metal aerogel, or metalloid aerogel. A three-dimensional nanoporous network may include a free radical initiator that reacts with a cross-linking agent to form the cross-linked aerogel. The cross-linked aerogel may be chemically aromatized and chemically carbonized to form a carbon-coated aerogel. The carbon-coated aerogel may be suitably processed to undergo a carbothermal reduction, yielding an aerogel where oxygen is chemically extracted. Residual carbon remaining on the surface of the aerogel may be removed via an appropriate cleaning treatment.

An hBN powder containing an aggregate of primary particles of hBN, the hBN powder having a ratio of an average longer diameter (L.sub.1) to an average thickness (d.sub.1) of the primary particles, [L.sub.1/d.sub.1], of 10 to 25, a tap density of 0.80 g/cm.sup.3 or more, and a BET specific surface area of less than 5.0 m.sup.2/g, in which a particle size distribution curve showing a frequency distribution based on volume of the hBN powder is a bimodal distribution curve having a first peak and a second peak in a range of a particle size of 500 μm or less and having a peak height ratio of a second peak height (H.sub.B) to a first peak height (H.sub.A), [(H.sub.B)/(H.sub.A)], of 0.90 or less, a method for producing the same, and a resin composition and a resin sheet each comprising the hBN powder.

An hBN powder containing an aggregate of primary particles of hBN, the hBN powder having a ratio of an average longer diameter (L.sub.1) to an average thickness (d.sub.1) of the primary particles, [L.sub.1/d.sub.1], of 10 to 25, a tap density of 0.80 g/cm.sup.3 or more, and a BET specific surface area of less than 5.0 m.sup.2/g, in which a particle size distribution curve showing a frequency distribution based on volume of the hBN powder is a bimodal distribution curve having a first peak and a second peak in a range of a particle size of 500 μm or less and having a peak height ratio of a second peak height (H.sub.B) to a first peak height (H.sub.A), [(H.sub.B)/(H.sub.A)], of 0.90 or less, a method for producing the same, and a resin composition and a resin sheet each comprising the hBN powder.

The present invention provides a radiation shielding material, particularly for shielding of particle radiation, comprising a fibre material and a radiation damping filler, wherein the amount of the radiation damping filler is 40 to 95 wt. % based on the dry weight of the radiation shielding material. The present invention further provides a radiation shielding structure, particularly for shielding of particle radiation, comprising a bottom layer and a top layer, wherein a hollow structure is sandwiched between the bottom layer and the top layer, wherein the hollow structure is filled with a radiation damping filler.

Ultrafast flash Joule heating synthesis methods and systems, and more particularly, ultrafast synthesis methods to recover precious metals recovery and other metals from electronic waste (e-waste).

A production method of boron carbide nano-sized particles and/or submicron particles includes the following sequential steps: obtention of a fluid mixture including elemental boron, glycerin and one or more carboxylic add, wherein a molar ratio of glycerin to the one or more carboxylic acids is within a range between 10:1 and 10:7.5. Heating of the fluid mixture to obtain a first mid-product in a form of a gel including borate ester bonds. Solidification of the first mid-product by heating a reaction product to obtain a second mid-product in solid form. Sintering the second mid-product to obtain boron carbide in a form of particles.

A production method of boron carbide nano-sized particles and/or submicron particles includes the following sequential steps: obtention of a fluid mixture including elemental boron, glycerin and one or more carboxylic add, wherein a molar ratio of glycerin to the one or more carboxylic acids is within a range between 10:1 and 10:7.5. Heating of the fluid mixture to obtain a first mid-product in a form of a gel including borate ester bonds. Solidification of the first mid-product by heating a reaction product to obtain a second mid-product in solid form. Sintering the second mid-product to obtain boron carbide in a form of particles.

A p-type semiconductor film including heterofullerene having a further sufficiently high hole mobility is provided. The p-type semiconductor film contains heterofullerene in which n+r number (where n and r are both positive odd numbers) of carbon atoms constituting a fullerene are substituted by n number of boron atom or atoms and r number of nitrogen atom or atoms.

A chemical synthesis method to fabricate boron carbide to obtain boron carbide fine powders includes the steps of: (A) formulating a precursor solution including a boron source, a liquid organic carbon source and a catalyst; (B) subjecting the precursor solution to a pyrolytic reaction in the presence of electromagnetic radiation to obtain a boron carbide precursor; and (C) subjecting the boron carbide precursor to a thermal energy treatment in the presence of thermal energy to obtain boron carbide fine powders.

A chemical synthesis method to fabricate boron carbide to obtain boron carbide fine powders includes the steps of: (A) formulating a precursor solution including a boron source, a liquid organic carbon source and a catalyst; (B) subjecting the precursor solution to a pyrolytic reaction in the presence of electromagnetic radiation to obtain a boron carbide precursor; and (C) subjecting the boron carbide precursor to a thermal energy treatment in the presence of thermal energy to obtain boron carbide fine powders.