Infrared reflectivity spectra of <Emphasis Type="Italic">η</Emphasis>-Na<Subscript>1.3</Subscript>V<Subscript>2</Subscript>O<Subscript>5</Subscript> in the charge disordered and ordered phase

We have measured the far-infrared reflectivity spectra of the sodium vanadium oxide η-Na_1.3V₂O₅ polycrystals in the wide temperature (80–300 K) and frequency (150–1500 cm⁻¹) range. Appearance of new phonon oscillators, phonon oscillator mode splitting and step-like shift of TO and LO frequencies at low temperatures are correlated with the charge-ordering phase transition, which takes place at about 120 K in this vanadium oxide.     

Low-frequency Raman scattering from CeO<Subscript>2</Subscript> nanoparticles

Raman scattering measurements were performed on CeO₂ nanoparticles at room temperature. Low-frequency modes are assigned to confined acoustic vibrations of spherical CeO₂ nanoparticles. Frequencies of these vibrational modes have been calculated in the elastic continuum approximation, which considers a nanoparticle as a homogeneous elastic sphere. We assumed stress-free boundary conditions. The specific dependence of the vibrational frequency on the particle diameter enables the determination of the particle size from the experimental Raman frequency. The particle size value calculated in this way agrees well with the value acquired from the phonon confinement model. PACS 61.46.Df; 73.63.Bd; 63.22.+m     

Holographic Three-Dimensional Display Using an Electron-Beam-Addressed Spatial Light Modulator

Three-dimensional (3-D) or holographic information extracted by two-dimensional active optical heterodyne scanning has been demonstrated recently. The technique is called optical scanning holography. To reconstruct the obtainable 3-D holographic information, digital techniques have been used and demonstrated. For real-time applications, we need to investigate spatial-light-modulator-based systems. In this paper, we first briefly review optical scanning holography, and then present experimental results of 3-D image reconstruction using an electron-beam-addressed spatial light modulator.     

The sixth Asian Symposium on Visualization

The sixth Asian Symposium on Visualization (ASV6) was successfully held from May 28th to 31st, 2001 in Busan, Korea. The activities of the organizing committee and ASV6 programs are outlined here in retrospect and the philosophy of ASV6 is described.     

Antiferromagnetic order in doped hubbard model under the magnetic field

We investigate the effects of temperature and hole doping on the antiferromagnetic (AF) ground states by considering the system of electrons on a two dimensional square lattice under the external magnetic field. In the mean field calculation of Hubbard Hamiltonian we find out that the magnetic field suppresses the AF order in a unique manner for all parameter values ofT and δ. We obtained the phase diagram of AF order inT-δ plane as a function of Coulomb correlation strength and magnetic field. We find the reentrant behavior of AF order in both the absence and the presence of magnetic field.     

Mixed convection of heat generating nanofluid in a lid-driven cavity with uniform and non-uniform heating of bottom wall

Steady state two-dimensional mixed convection in a lid-driven square cavity filled with Cu  –water nanofluid is investigated numerically in the presence of internal heat generation. In the present investigation, bottom wall is uniformly and non-uniformly heated while two vertical walls are fixed and they are thermally insulated. The top wall is moving from left to right at a constant speed. The governing equations are normalized and solved numerically with boundary conditions by finite volume approach using third order accurate upwinding scheme (deferred QUICK). Effects of the pertinent physical parameters are investigated in terms of the flow and temperature fields, as well as Nusselt number distributions. The presented results show that the solid volume fraction plays a significant role on the flow and thermal fields and the Nusselt number distributions for different flow configurations. It is found that Richardson number strongly affect the fluid flow and heat transfer in the cavity. For Ri<1$\mathit{Ri}<1$, the forced convection becomes dominant in the entire cavity, the natural convection relatively weak.     

Electrochemical determination of whole blood clotting time by using nanodot arrays

Simple and cost-effective process for the fabrication of a nanodot strip which can electrochemically determine blood coagulation time was described in detail. We observed that the beginning of blood coagulation on the nanodot surface gives rise to increase in resistance against current flow, leading to suddenly increase in potential when constant current is applied between the nanodot electrodes. Interestingly, such dramatic increase in potential was not observed in the plain surface and non-controlled rough surface.     

Synthesis and magnetic properties of colloidal MnPt3 nanocrystals

The colloidal synthesis and magnetic properties of MnPt(3) nanocrystals are reported. The nanocrystal size depended on the Mn reactant used, but the Mn:Pt stoichiometry was always 1:3. As synthesized, the nanocrystals are compositionally disordered with the face-centered cubic (fcc) A1 phase. Annealing at 580 degrees C changed the MnPt(3) crystal structure to the compositionally ordered L1(2) phase (AuCu(3) structure) with higher magnetocrystalline anisotropy. Magnetization measurements showed that the A1 nanocrystals are paramagnetic and the L1(2) MnPt(3) nanocrystals are superparamagnetic.