An extended hydrodynamic theory for particle coarsening—I: Theory

The asymptotic hydrodynamic approach to the mathematical solution of the kinetics of particle coarsening (Ostwald ripening), first proposed by Lifshitz and Slyozov and Wagner, has been extended and generalized. The coarsening rate equations in dimensionless forms have been separated into asymptotically determinate and indeterminate parts. The generalized evaluation of the asymptotically indeterminate part allows the consideration of coarsening processes that are more complicated than those involving power law type kinetics considered in previous studies. Further, the extended theory allows the determination of particle size distribution function and averaged particle coarsening kinetics even in cases where different physical processes occur at different size regimes within the same distribution of particles.     

Anisotropic electrical properties of Bi0.5(Na0.75K0.25)0.5TiO3 ceramics fabricated by reactive templated grain growth (RTGG)

We have fabricated lead-free Bi_0.5(Na_0.75K_0.25)_0.5TiO₃ (BNKT) ceramics by a conventional process (CP) and reactive templated grain growth (RTGG) methods. The effect of grain orientation on structure, dielectric, complex impedance and electrical properties was investigated. The phase formation and grain morphology of BNKT ceramics were examined by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. High dielectric constant and low dielectric loss was observed for grain oriented (textured) BNKT ceramics. Complex impedance, temperature dependent ac and dc conductivity were performed to explore the conduction behavior of the prepared BNKT ceramics.     

Search for neutral, long-lived particles decaying into two muons in pp[over] collisions at sqrt[s]=1.96 TeV

We present a search for a neutral particle, pair produced in pp[over] collisions at sqrt[s]=1.96 TeV, which decays into two muons and lives long enough to travel at least 5 cm before decaying. The analysis uses approximately 380 pb(-1) of data recorded with the D0 detector. The background is estimated to be about one event. No candidates are observed, and limits are set on the pair-production cross section times branching fraction into dimuons + X for such particles. For a mass of 10 GeV and lifetime of 4x10(-11) s, we exclude values greater than 0.14 pb (95% C.L.). These results are used to limit the interpretation of NuTeV's excess of dimuon events.     

Dependence of turbidity oscillations of self-oscillating polymers on the selective recognition of the crown ether receptors contained in the polymer chain

The turbidity oscillations of self-oscillating polymers in the Belousov-Zhabotinsky (BZ) reaction system depending on the crown ether receptors contained in the polymer network have been studied. The three monomers are copolymerized, namely, N-isopropylacrylamide, the metal catalyst monomer for the BZ reaction, and the crown ether receptor monomer, to prepare the self-oscillating polymers used in this study. The turbidity oscillations are characterized by monitoring the transmittance of the polymer solution in the BZ reaction system at a specific wavelength of 570 nm. The oscillations are varied by crown ether receptors used in the polymerization process, i.e., BCAm(6) or BCAm(5), for the selective recognition of specific cations between potassium and sodium ions in the solution. The selective recognition of the BCAm receptors in the polymer chain for the two ions has brought out a variation in the turbidity oscillations by a change in the hydrophilicity of the polymer chain. The oscillations of the polymer solution composed of the BCAm(5) receptor are more influenced by sodium ion, while the polymer solution of BCAm(6) receptor is affected by potassium ion. However, the oscillation patterns of the redox changes obtained by these solution systems look much alike despite the differences in the polymer chain by crown ether receptors and cations of bromate used for the BZ reaction.     

A preparative isolation and purification of arctigenin and matairesinol from Forsythia koreana by centrifugal partition chromatography

Centrifugal partition chromatography was applied to separate arctigenin and matairesinol from Forsythia koreana extract with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (5:5:5:5 v/v). Using this method, arctigenin and matairesinol were successfully separated from partially purified F. koreana extracts in only one step. The purities of isolated compounds were determined to be over 90% by HPLC analysis.     

Fatigue-resistant photochromic dithienylethenes by controlling the oxidation state

High fatigue-resistant photochromic dithienylethenes were synthesized by controlling the oxidation state of 1,2-bis(2-methyl-1-benzothiophene-3-yl)perfluorocyclopentene (BTF6) and 1,2-bis(2,5-dimethylthien-3-yl)perfluorocyclopentene (DMTF6).     

Tripodal oxazoline-based homochiral coordination cages with internal binding sites

Homochiral coordination cages, which have two well-defined internal binding sites for ammonium and organoammonium ions, have been constructed by Pd(II)-mediated self-assembly of preorganized tripodal oxazolines containing pyridine pendant groups.     

Spliced-fiber mode filter for 1060-nm single-mode transmission

We present a novel mode filter operating for the 1060-nm band, which selectively removes the power of the high-order mode (HOM) from a conventional single-mode fiber (C-SMF) that supports two modes at the short-wavelength band. Our mode filter is fabricated very easily by fusion-splicing a short section of short-wavelength single-mode fiber in the middle of the C-SMF link. By using our spliced-fiber mode filter (SF-MF), a high HOM suppression performance of > 18 dB has been achieved with a low insertion loss of < 0.3 dB over the full band of optical communications from 1050 nm to 1650 nm. We have also developed a new mode power measurement scheme that takes advantage of the bending sensitivity of the HOM guidance. This measurement scheme enabled us to evaluate accurately the performance factors of the fabricated mode filter.     

Charged-particle multiplicity density at midrapidity in central Pb-Pb collisions at sqrt[S(NN)] = 2.76 TeV

The first measurement of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at a center-of-mass energy per nucleon pair √ S NN = 2.76 TeV is presented. For an event sample corresponding to the most central 5% of the hadronic cross section, the pseudorapidity density of primary charged particles at midrapidity is 1584 ± 4(stat) ± 76(syst), which corresponds to 8.3 ± 0.4(syst) per participating nucleon pair. This represents an increase of about a factor 1.9 relative to pp collisions at similar collision energies, and about a factor 2.2 to central Au-Au collisions at √ S NN = 2.76 TeV. This measurement provides the first experimental constraint for models of nucleus-nucleus collisions at LHC energies.