Wan Bae Kim

Different nanostructures (Ns), such as nanobelts, nanobricks and nanosheets, of polypyrrole (PPy) were successfully fabricated on stainless steel substrates by simply varying the scan rate of deposition in the potentiodynamic mode. These PPy Ns were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and surface area measurement. The XRD analysis showed the formation of amorphous

SQL is a high-level nonprocedural data language which has received wide recognition in relational databases. One of the most interesting features of SQL is the nesting of query blocks to an arbitrary depth. An SQL-like query nested to an arbitrary depth is shown to be composed of five basic types of nesting. Four of them have not been well understood and more work needs to be done to improve their execution efficiency. Algorithms are developed that transform queries involving these basic types o

I. NEXT-GENERATION DATABASE TECHNOLOGY. 1. Introduction to Part 1: Next-Generation Database Technology. 2. The OMG Model. 3. Object SQL---Language for the Design and Implementation of Object Databases. 4. OQL(C++): Extending C++ with an Object Query Capability. 5. C++ Bindings to an Object Database. 6. On View Support in Object-Oriented Database Systems. 7. Authorization in Object-Oriented Databases. 8. Query Processing in Object-Oriented Database Systems. 9. Physical Object Management. 10. Requ

We prepared metallic-nanoparticle-embedded one-dimensional titanium dioxide (1D-TiO 2 ) via a one-step electrospinning process, in which Au or Ag metallic nanoparticles between 5 and 10 nm in diameter were incorporated within the TiO 2 nanofibers. After calcination of the composite nanofibers at high temperature of 450 °C, the nanofibers were converted to 1D-TiO 2 by the thermal decomposition of polyvinylpyrrolidone (PVP). This process simultaneously changed the metal precursors (AgNO 3 or HAuCl

Electricity was produced by catalytic oxidation of carbon monoxide (CO) by using gold catalysts at room temperature. The observed rates are faster than conventional processes operating at 500 kelvin or higher for the conversion of CO with water to produce hydrogen and carbon dioxide through the water-gas shift (WGS). By eliminating the WGS reaction, we remove the need to transport and vaporize liquid water in the production of energy for portable applications. This process can use CO-containing

In object-oriented systems, an object may recursively reference any number of other objects. The references, however, do not capture any special relationships between objects. An important semantic relationship which may be superimposed on a reference is the IS-PART-OF relationship between a pair of objects. A set of objects related by the IS-PART-OF relationship is collectively called a composite object. An earlier paper [KIM87b] presented a model of composite objects which has been implemented

Abstract Recently our modern society is demanding flexible, low‐cost, and lightweight electrochemical energy storage systems, which are very important in variety of applications ranging from portable consumer electronics to large industrial‐scale power and energy management. Among different energy storage systems, flexible supercapacitors have been considered as one of the most promising candidates due to their significant merits such as high power density along with the unique properties of bei

In this paper, ZnMn2O4 mesoscale tubular arrays on current collectors were successfully synthesized using a reactive template route combined with a postcalcination process through the shape-preserving conversion of ZnO nanorod arrays in aqueous solutions at room temperature. On the basis of the experimental analyses, including X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy, a plausible formation mechanism of ZnMn2O4 tubular arrays was pr

A surfactantless, one-pot reduction approach for Pd@Pt core–shell nano-stars on reduced graphene oxide with enhanced catalytic activity and stability for methanol oxidation in alkaline media.