A preparation method of a tetragonal NaV.sub.2O.sub.5.H.sub.2O nanosheet-like powder includes steps of: (Step 1) simultaneously adding NaVO.sub.3 and Na.sub.2S.9H.sub.2O into deionized water, and then magnetically stirring, and obtaining a black turbid solution; (Step 2) sealing after putting the black turbid solution into an inner lining of a reaction kettle, fixing the sealed inner lining in an outer lining of the reaction kettle, placing the reaction kettle into a homogeneous reactor, and then performing a hydrothermal reaction; and (Step 3) after completing the hydrothermal reaction, naturally cooling the reaction kettle to the room temperature, and then alternately cleaning through water and alcohol, and then collecting a product, drying the product, and finally obtaining the tetragonal NaV.sub.2O.sub.5.H.sub.2O nanosheet-like powder with a thickness in a range of 30-60 nm and a single crystal structure grown along a (002) crystal orientation.

A method for producing an aggregated boron nitride particle, containing: a nitriding step of nitriding a particle containing boron carbide to obtain a particle containing boron carbonitride; and a decarburizing step of decarburizing the particle containing boron carbonitride to obtain an aggregated boron nitride particle, wherein, in the nitriding step, nitriding is performed so that boron carbide remains inside the particle containing boron carbonitride, and wherein, in the decarburizing step, the boron carbide remaining inside the particle containing boron carbonitride is removed.

A method, including irradiating graphene oxide (GO) with a beam of light or radiation to form reduced graphene oxide (RGO) in a three-dimensional (3D) pattern, wherein the RGO is porous RGO with pores having sizes tuned by controlling the beam of light or radiation.

Provided is a boron nitride agglomerate. The boron nitride agglomerate is of a multi-stage structure formed by arranging flaky hexagonal boron nitride primary particles in three-dimensional directions through adhesion of an inorganic binder. Further provided is a method for preparing the boron nitride agglomerate. The method comprises: mixing flaky hexagonal boron nitride primary particles with an inorganic binder, and controlling the mass of the inorganic binder to account for 0.02-20% of the mass of the flaky hexagonal boron nitride primary particles, so as to obtain the boron nitride agglomerate. The boron nitride agglomerate provided can be added to thermosetting resin compositions, and resin sheets, resin composite metal foil, prepregs, laminates, metal foil-covered laminates, and printed wiring boards prepared using the same have higher boron nitride addition, high thermal conductivity, and high peel strength.

A quantum dot including a core comprising a first semiconductor nanocrystal including a zinc chalcogenide and a semiconductor nanocrystal shell disposed on the surface of the core and comprising zinc, selenium, and sulfur. The quantum dot does not comprise cadmium, emits blue light, and may exhibit a digital diffraction pattern obtained by a Fast Fourier Transform of a transmission electron microscopic image including a (100) facet of a zinc blende structure. In an X-ray diffraction spectrum of the quantum dot, a ratio of a defect peak area with respect to a peak area of a zinc blende crystal structure is less than about 0.8:1. A method of producing the quantum dot, and an electroluminescent device including the quantum dot are also disclosed.

Disclosed are a carbon nanotube (CNT)-based three-dimensional ordered macroporous (3DOM) carbon material and a preparation method thereof. The CNT-based 3DOM carbon material comprises a honeycomb network structure having a 3DOM structure formed by overlapping CNTs, wherein ordered macropores each have a diameter of 270 nm to 360 nm, and the CNTs each have an outer diameter of 8 nm to 20 nm

Provided is a piezoelectric thin film device containing: a first electrode layer; and a piezoelectric thin film. The first electrode layer contains a metal Me having a crystal structure. The piezoelectric thin film contains aluminum nitride having a wurtzite structure. The aluminum nitride contains a divalent metal element Md and a tetravalent metal element Mt. [Al] is an amount of Al contained in the aluminum nitride, [Md] is an amount of Md contained in the aluminum nitride, [Mt] is an amount of Mt contained in the aluminum nitride, ([Md]+[Mt])/([Al]+[Md]+[Mt]) is 36 to 70 atom %. L.sub.ALN is a lattice length of the aluminum nitride in a direction that is approximately parallel to a surface of the first electrode layer with which the piezoelectric thin film is in contact, L.sub.METAL is a lattice length of Me in a direction, and L.sub.ALN is longer than L.sub.METAL.

Provided is a molybdenum sulfide that is ribbon-shaped and particularly suitable for a hydrogen generation catalyst. Disclosed are a ribbon-shaped molybdenum sulfide, in which 50 particles as measured by observation with a scanning electron microscope (SEM) have a shape of, on average, 500 to 10000 nm in length, 10 to 1000 nm in width, and 3 to 200 nm in thickness; a method for producing the ribbon-shaped molybdenum sulfide, including: (1) heating a molybdenum oxide at a temperature of 200 to 1000° C. in the presence of a sulfur source; or (2) heating a molybdenum oxide at a temperature of 100 to 800° C. in the absence of a sulfur source, and then heating the molybdenum oxide at a temperature of 200 to 1000° C. in the presence of a sulfur source; and a hydrogen generation catalyst including the ribbon-shaped molybdenum sulfide.

According to an embodiment, a method for preparing a sea urchin-shaped zinc oxide (ZnO) nanowire comprises preparing a mixture of a ZnO nano-powder and a graphite powder and irradiating the mixture, in a container, with a microwave.

A graphite membrane includes graphene layers, wherein the graphite membrane is an independent graphite membrane having a thickness of 10 nm to 12 μm, an area of 5×5 mm.sup.2 or more, an electrical conductivity of 8000 S/cm or more, and an arithmetic average roughness Ra of 200 nm or less on a surface of the graphite membrane.