Chonbuk National University

About: Chonbuk National University is a education organization based out in Jeonju, South Korea. It is known for research contribution in the topics: Apoptosis & Nanofiber. The organization has 14820 authors who have published 28884 publications receiving 554131 citations.

A new reverse jacket transform and its fast algorithm

Abstract: This paper presents the reverse jacket transform [RJT] and a simple decomposition of its matrix, which is used to develop a fast algorithm for the RJT. The matrix decomposition is of the form of the matrix products of Hadamard matrices and successively lower order coefficient matrices. This decomposition very clearly leads to a block circular sparse matrix factorization of the reverse jacket [RJ]/sub N/ matrix. The main property of [RJ]/sub N/ is that the inverse matrices of its elements can be obtained very easily and have a special structure. [RJ]/sub N/ is derived using the weighted Hadamard transform corresponding to the Hadamard matrix [H]/sub N/ and a basic symmetric matrix /spl Lambda/. Each element of [RJ]/sub N/ is a generalized for polygonal subsampling and canonical Smith form. In this paper we represent in particular the systematical block-wise sparse matrix of extending-method for [RJ]/sub N/.

In situ synthesis of thermochemically reduced graphene oxide conducting nanocomposites.

Abstract: Highly conductive reduced graphene oxide (GO) polymer nanocomposites are synthesized by a well-organized in situ thermochemical synthesis technique. The surface functionalization of GO was carried out with aryl diazonium salt including 4-iodoaniline to form phenyl functionalized GO (I-Ph-GO). The thermochemically developed reduced GO (R-I-Ph-GO) has five times higher electrical conductivity (42 000 S/m) than typical reduced GO (R-GO). We also demonstrate a R-I-Ph-GO/polyimide (PI) composites having more than 104 times higher conductivity (∼1 S/m) compared to a R-GO/PI composites. The electrical resistances of PI composites with R-I-Ph-GO were dramatically dropped under ∼3% tensile strain. The R-I-Ph-GO/PI composites with electrically sensitive response caused by mechanical strain are expected to have broad implications for nanoelectromechanical systems.

Hierarchical 3D Cobalt-Doped Fe3O4 Nanospheres@NG Hybrid as an Advanced Anode Material for High-Performance Asymmetric Supercapacitors

Abstract: Hierarchical nanostructure, high electrical conductivity, extraordinary specific surface area, and unique porous architecture are essential properties in energy storage and conversion studies. A new type of hierarchical 3D cobalt encapsulated Fe3O4 nanosphere is successfully developed on N-graphene sheet (Co−Fe3O4 NS@NG) hybrid with unique nanostructure by simple, scalable, and efficient solvothermal technique. When applied as an electrode material for supercapacitors, hierarchical Co−Fe3O4 NS@NG hybrid shows an ultrahigh specific capacitance (775 F g−1 at a current density of 1 A g−1) with exceptional rate capability (475 F g−1 at current density of 50 A g−1), and admirable cycling performance (97.1% capacitance retention after 10 000 cycles). Furthermore, the fabricated Co−Fe3O4 NS@NG//CoMnO3@NG asymmetric supercapacitor (ASC) device exhibits a high energy density of 89.1 Wh kg−1 at power density of 0.901 kW kg−1, and outstanding cycling performance (89.3% capacitance retention after 10 000 cycles). Such eminent electrochemical properties of the Co−Fe3O4 NS@NG are due to the high electrical conductivity, ultrahigh surface area, and unique porous architecture. This research first proposes hierarchical Co−Fe3O4 NS@NG hybrid as an ultrafast charge−discharge anode material for the ASC device, that holds great potential for the development of high-performance energy storage devices.