Abstract: Disclosed is a method for fabrication of porous carbon fibers. More particularly, the method for fabrication of porous carbon fibers comprises the steps of: processing starch to prepare a gelled starch solution; adding organic acid to the gelled starch solution to prepare a starch solution; dissolving carbon nanotubes in a solvent and adding fiber formable polymer thereto to prepare a carbon nanotube/fiber formable polymer solution; mixing the starch solution with the carbon nanotube/fiber formable polymer solution obtained from the above steps, in order to prepare a carbon nanotube/starch/fiber formable polymer solution; electro-spinning or wet-state spinning the prepared carbon nanotube/starch/fiber formable polymer solution to produce starch composite fibers; oxidation heating the starch composite fibers, then, executing carbonization and vacuum heat treatment of the heated fibers, so as to fabricate the porous carbon fibers.

Abstract: Disclosed is a method for fabricating carbon nanotube-metal-polymer nanocomposites, in particular, to a method for fabricating a carbon nanotube-metal-polymer nanocomposite wherein the carbon nanotubes decorated with metal portion in a necklace form are homogeneously dispersed in a polymer base. The method for fabricating a carbon nanotube-metal-polymer nanocomposite comprises: preparing carbon nanotube-metal nanocomposite powder by introducing a polyol reducing agent as well as metal precursor in a carbon nanotube colloidal solution and heating the same; dispersing the carbon nanotube-metal nanocomposite powder in a polymer base; and curing the polymer base to form the carbon nanotube-metal-polymer nanocomposite. According to the present invention, as the carbon nanotubes decorated with metal particles in a necklace form are homogeneously dispersed in the polymer base, microwave absorbing and shielding properties of the final product are improved.

Abstract: The present invention relates to a long-life carbon nanotube field emitter with a three-dimensional structure and method for fabricating the same. Since the emitter having an extended area according to the design of the present invention can minimize the current density flowing per single wire of the carbon nanotube, it can be expected that the damage of the carbon nanotube is minimized so that the lifetime of the field emitter can be significantly improved and the commercialization of the carbon nanotube field emitter will be advanced.

Abstract: The present invention relates to methods of preparing a polymer composite using a giant magnetostrictive material, and more particularly, to polymers composite having various improved properties, in which the advantageous structure of the giant magnetostrictive material produced by unidirectional solidification can be maintained by removing the eutectic phase from the magnetostrictive material and filling resulting voids with a polymer resin.

Abstract: The present invention relates to a metal nanocomposite powder reinforced with carbon nanotubes and to a process of producing a metal nanocomposite powder homogeneously reinforced with carbon nanotubes in a metal matrix powder.

Abstract: Disclosed herein is a flexible self-expandable stent using shape memory alloy for expanding stenosal portions and method and apparatus for fabricating the same.

Abstract: Disclosed herein is a flexible self-expandable stent using shape memory alloy for expanding stenosal portions and method and apparatus for fabricating the same.

Abstract: This invention relates to methods of preparing oxidation protective coating layers for carbon/carbon composites. More specifically, the invention is directed to a method of applying an oxidation protective coating to a carbon/carbon composite. The method is characterized by the formation of two or more layers of coating on the carbon/carbon composite by using Si.

Abstract: This invention relates to methods of preparing oxidation protective multiple coating layers for carbon/carbon composites. More specifically, the invention is directed to a method of applying an oxidation protective multiple coating to a carbon/carbon composite. The method is characterized by the formation of two or more layers of coating on the carbon/carbon composite by using Si.

Abstract: The invention relates to methods for fabricating ceramic nanocomposite powders, comprising a ceramic matrix and carbon nanotubes homogeneously dispersed in the ceramic matrix. The ceramic nanocomposite powders of the invention can prevent property deterioration due to agglomeration of carbon nanotubes.

Abstract: Disclosed is a method for producing an SiC preform of a high volume fraction used for the manufacture of a metal matrix composite. The method involves the steps of mixing SiC particles of different particle sizes each selected from a range of 0.2 to 48 &mgr;m with an organic binder, an inorganic binder, an aggregating agent, and distilled water, thereby producing a mixture, and stirring the mixture in accordance with a ball milling process, thereby producing a slurry containing the SiC particles, pouring the slurry containing the SiC particles into a mold having upper and lower molds respectively provided with absorbent bodies, and squeezing the slurry in the mold, thereby reducing a residual moisture content of the slurry, completely drying the slurry reduced in residual moisture content, thereby producing an SiC preform, and calcinating the SiC preform. The preform is impregnated with a metal matrix while maintaining a high reinforcement volume fraction of 70 vol % or more.

Abstract: Disclosed herein is a flexible self-expandable stent using shape memory alloy for expanding stenosal portions and method and apparatus for fabricating the same.

Abstract: Disclosed is a process for making an oxide dispersion-strengthened tungsten heavy alloy by mechanical alloying that includes the steps of: adding 0.1 to 5 wt. % of Y2O3 powder to a mixed powder comprising more than 90 wt. % of tungsten powder, and nickel and iron powders for the rest; and subjecting the resulting mixture to a mechanical alloying to prepare an oxide dispersion-strengthened tungsten heavy alloy powder. The oxide dispersion-strengthened tungsten heavy alloy prepared by the mechanical alloying is characterized in that fine Y2O3 particles are uniformly dispersed in the matrix which are stable at high temperatures results in enhanced high-temperature strength and a reduction of the shearing strain of the fraction during high strain rate deformation.

Abstract: Disclosed is a process for making an oxide dispersion-strengthened tungsten heavy alloy by mechanical alloying that includes the steps of: adding 0.1 to 5 wt. % of Y2O3 powder to a mixed powder comprising more than 90 wt. % of tungsten powder, and nickel and iron powders for the rest; and subjecting the resulting mixture to a mechanical alloying to prepare an oxide dispersion-strengthened tungsten heavy alloy powder. The oxide dispersion-strengthened tungsten heavy alloy prepared by the mechanical alloying is characterized in that fine Y2O3 particles are uniformly dispersed in the matrix which are stable at high temperatures results in enhanced high-temperature strength and a reduction of the shearing strain of the fracture during high-speed shear deformation.

Abstract: The present invention relates to a method of preparing a preform with a high volume fraction of SiC particles. A slurry containing SiC particles and binders is ball-milled and pressed in an apparatus to give a primary preform. This primary preform is dried at room temperature and then, at a high temperature. The dried primary preform is subjected to calcination to prepare the preform. In the apparatus, which comprises a bottom die; a top mold with a cavity, placed on the bottom die, an upper punch for pressing a material for the preform in the cavity; and two water-absorbers, one being inserted between the bottom die and the top mold, the other being placed on the top mold, the slurry is introduced in the cavity and pressed by the punch while the water is absorbed in the absorbers or drained through a gap between the bottom die and the top mold, thereby improving the volume fraction of SiC particles.

Abstract: The present invention provides a Fe--Mn--Cr--Al cryogenic alloy having high ductility, strength, toughness and corrosion-resistance, and a process for preparing the same. The cryogenic structural alloy of the invention is prepared by the steps of: air-induced melting of a metallic alloy composition which consists of Fe 48.6 to 64.7 wt %, Mn 25.0 to 35.0 wt %, Cr 10.0 to 13.0 wt %, Al 0.1 to 2.0 wt %, C 0.1 to 0.4 wt % and Si 0.1 to 1.0 wt %; hot-rolling of the melted alloy at 1,090.degree. to 1,110 .degree. C.; and, solution heat treatment of the hot-rolled alloy at 1,040.degree. to 1,060.degree. C. for 50 to 70 minutes.