Propagating surface plasmon polaritons for remote excitation surface-enhanced Raman scattering spectroscopy

To illustrate the attractive potentials of remote-excitation surface enhanced Raman scattering (RE-SERS), we review the fundamental concepts and typical applications of propagating surface plasmon polaritons (PSPPs). Based on the RE-SERS technic, the adsorbed molecules are protected from being directly illuminated, while the merits of SERS still remained. However, the critical limitations of applying RE-SERS hinder its rapid development. Hence, drawing an overview about the PSPPs would be beneficial for further promoting the significance of RE-SERS in biological application and investigating the mechanism of surface catalytic reactions.     

Painlevé analysis,lump-kink solutions and localized excitation solutions for the (3+1)-dimensional Boiti–Leon–Manna–Pempinelli equation

In this paper the (3+1)-dimensional Boiti–Leon–Manna–Pempinelli (BLMP) equation is investigated. The integrability test is performed yielding a positive result. Through the Painlevé–Bäcklund transformation, we derive four types of lump-kink solutions composed of two quadratic functions and N exponential functions. It is shown that fission and fusion interactions occur in the lump-kink solutions. Furthermore, a new variable separation solution with two arbitrary functions is obtained, the localized excitations including lumps, dromions and periodic waves are analyzed by some graphs.     

Photoluminescence of green nanophosphors Sr2MgSi2O7 doped with Tb3+ under 374-nm excitation

A series of Sr₂MgSi₂O₇:Tb³⁺ nanophosphors is prepared using a high-temperature solid-state reaction. The x-ray diffraction patterns show that the crystal structure of the sample is not significantly affected by Tb³⁺ ions. However, the images of the scanning electron microscope illustrate that the average size of nanoparticles becomes larger with the increase of Tb³⁺ concentration. Unlike earlier investigations on down-conversion emission of Tb³⁺ ion excited by deep ultraviolet light, in this work, the photoluminescence characteristics of Sr₂MgSi₂O₇ nanophosphors doped with different Tb³⁺ concentrations are analyzed under 374-nm excitations. The intense green emission at 545 nm is observed at an optimal doping concentration of 1.6 mol%. The main reason for the concentration quenching is due to the electric dipole-electric dipole interaction among Tb³⁺ ions.     

The stabilization of partially-premixed jet flames in the presence of high potential electric fields

Numerous research efforts have focused on flame stabilization and emissions. Based on initial experiments, specific mechanisms resulting from DC electric fields were chosen to be investigated, namely the chemical, thermal, and ionization mechanisms. Numerical simulations were performed on premixed propane-ozone-air flames to characterize ozone effects on flame speed resulting from the formation of ozone in high potential electric fields. These results were compared against partially premixed flame experiments to observe the dominant influences within leading edge stabilization within high potential electric fields. It was found that the electromagnetic or ionization influences, serve as the dominant effect on the combustion zone.     

Dark lump excitations in superfluid Fermi gases

We study the linear and nonlinear properties of two-dimensional matter-wave pulses in disk-shaped superfluid Fermi gases.A Kadomtsev-Petviashvili I(KPI) solitary wave has been realized for superfluid Fermi gases in the limited cases of Bardeen-Cooper-Schrieffer(BCS) regime,Bose-Einstein condensate(BEC) regime,and unitarity regime.Onelump solution as well as one-line soliton solutions for the KPI equation are obtained,and two-line soliton solutions with the same amplitude are also studied in the limited cases.The dependence of the lump propagating velocity and the sound speed of two-dimensional superfluid Fermi gases on the interaction parameter are investigated for the limited cases of BEC and unitarity.     

Wie empfindlich sind Gehaltsbestimmungen durch Röntgenanregung mittels radioaktiver Röntgenquellen?

Mit Berücksichtigung eines die horizontale Probeausdehnung umfassenden Geometriefaktors werden unter praktisch brauchbaren Bedingungen absolute Fluoreszens- und Streustrahlungsausbeuten für sättigungsdicke und für dünne Proben berechnet. Die aus ihnen herleitbaren Meβempfindlichkeiten zeigen, daβ sich geringe Konzentrationen von relativ leichten bis mittelschweren Elementen besonders gut messen lassen, wenn man entweder dicht oberhalb der Absorptionskanten liegenda Energien anwendel oder bei relativ hoher Anregungsenergie die Streustahlung abtrennt. Bei groβen Konzentrationen solcher Elemente kann auch ohne Streustrahlungsabtrennung mit relativ hohen Anregungsenergien gemessen werden, wobei sogar unter gewissen Bedingungen mit Zunahme der Anregungsenergie eine leichte Empfindlichkeitsverbesserung eintritt. Bei schweren Elementen ist der Gesichtspunkt der Probendicke vielfach wichtiger als die Wahl der Anregungsenergie. Für dūnne Proben lassen sich relativ recht hohe Empfindlichkeiten erzielen, was jedoch zu einem Problem der absoluten Intensitāten angesichts des Detektor-Strahlungsuntergrundes fūhren kann.     

Theoretical computation of low‐lying electronic states of HCNS: A CASPT2 study

Complete active space self‐consistent field (CASSCF) and complete active space second‐order perturbation theory (CASPT2) calculations in conjunction with the aug‐cc‐pVTZ basis set have been used to investigate the low‐lying electronic states of thiofulminic acid (HCNS), HCNS⁺, and HCNS^?. The result of geometry optimization using CASPT2/aug‐cc‐pVTZ shows that theoretically determined geometric parameters and harmonic vibrational frequencies for the HCNS ground state X¹Σ⁺(X¹A′) are in agreement with previous studies. The ionization energies, the electron affinity energies, the adiabatic excitation energies, and vertical excitation energies have been calculated and the corresponding cation and anion states are identified. By calculating adiabatic electron affinity, the states of HCNS^? have been identified to contain both π orbital states (X²A′ and 1²A″) and dipole‐bond states (1⁴A′ and 1⁴A″). © 2012 Wiley Periodicals, Inc.     

In–out asymmetry and interference effects in plasmon excitation by swift charged particles traversing a surface

We investigate the excitation of plasmons by a fast charged particle moving in the vicinity or traversing the surface of a solid along an arbitrary trajectory. We use both quantum‐mechanical and semiclassical dielectric formulations to study how the particle couples with the bulk and surface excitations. We pay special attention to the differences and similarities between incoming and outgoing trajectories, finding some novel oscillatory structures that can be ascribed to an interference effect between direct and reflected plasmon excitations. Copyright © 2013 John Wiley & Sons, Ltd.     

Asymmetrical flow field-flow fractionation and excitation-emission matrix spectroscopy combined with parallel factor analyses of riverine dissolved organic matter isolated by tangential flow ultrafiltration

Asymmetrical flow field-flow fractionation (AF4) with sequential on-line UV/visible and fluorescence detectors was used to investigate the composition of dissolved organic matter (DOM) in permeate and retentate fractions isolated by tangential flow ultrafiltration (TFF) at various concentration factors (i.e. ratio of initial volume to the retentate volume; CF). The permeation coefficient model, which defines the log-log relationship between DOM in the permeate fractions and CFs, described the permeation behaviour of DOM with regression coefficients r ² > 0.99. The dominance of higher-molecular weight retentate chromophoric DOM (CDOM) observed in TFF was consistent with the results of AF4. The weight-averaged molecular weights (M _w) of the integral permeate and retentate at CF = 20 were determined to be 1160 and 2320 by AF4, respectively, while their molecular weight distributions (MWD) were centered at 1120 and 1600 Da. M _w, MWD, and aromaticity (i.e. ratio of absorbance at 250 and 365 nm; E2/E3) in permeate fractions were altered significantly during the early stages of TFF (CF < 9). These changes, however, were not evident in excitation-emission matrix fluorescence properties as determined using the parallel factor analysis model. The application of AF4 to TFF fractions suggests that the choice of CF may have an important impact on the size distribution and aromaticity of permeate fractions, whereas fluorescence properties appear insensitive to concentration factor. These results suggest that the choice of CF is crucial only in the study of the permeate fraction where similar CF (i.e. > 9) should be used to obtain meaningful comparison among samples.