Study of the reactione + e −→K + K − in the energy range1350 \leqq \sqrt s \leqq 2400 MeV

Thee ⁺ e ^?→K ⁺ K ^? cross section has been measured from about 750 events in the energy interval \(1350 \leqq \sqrt s \leqq 2400 MeV\) with the DM2 detector at DCI. TheK ^± form factor |F _F ^±| cannot be explained by the ρ, ω, ? and ρ′(1600). An additional resonant amplitude at 1650 MeV has to be added as suggested by a previous experiment.     

Nitro-oxidized carboxycellulose nanofibers from moringa plant: effective bioadsorbent for mercury removal

Cellulose - Mercury contamination in drinking water is a worldwide problem due to its severely harming effects on the human body. A nanostructured natural bioadsorbent, carboxycellulose nanofiber...     

Radiative decay ofJ/ψ into γ π+ π−

The radiative decayJ/ψ → γ π⁺ π^? has been studied using the 8.6 millionJ/ψ produced in the DM2 experiment at the DCIe ⁺e^? storage rings at Orsay. The π⁺ π^? mass spectrum shows a cleanf ₂ (1270) signal, and the possible presence of two other states at thef ₂ (1720) andf ₄ (2030) masses. For thef ₂ (1270), the branching ratio BR(J/ψ →γf)xBR(f→π⁺ π^?) is measured to be (7.50±0.30±1.12)×10^?4, and the spin analysis prefers theJ=2 assignment, with helicity parametersx=0.83±0.06 andy=0.01±0.06. The existence of higher mass states is discussed.     

Synthesis and characterization of thermoresponsive amphiphilic block copolymers incorporating a poly(ethylene oxide‐stat‐propylene oxide) block

Amphiphilic BuO‐(PEO‐stat‐PPO)‐block‐PLA‐OH diblock and MeO‐PEO‐block‐(PEO‐stat‐PPO)‐block‐PLA‐OH triblock copolymers incorporating thermoresponsive poly(ethylene oxide‐stat‐propylene oxide) (PEO‐stat‐PPO) blocks were prepared by ring‐opening polymerization of lactide (LA) initiated by macroinitiators formed from treating BuO‐(PEO‐stat‐PPO)‐OH and MeO‐PEO‐block‐(PEO‐stat‐PPO)‐OH with AlEt₃. MeO‐PEO‐block‐(PEO‐stat‐PPO)‐OH was prepared by coupling MeO‐PEO‐OH and HO‐(PEO‐stat‐PPO)‐OH, followed by chromatographic purification. The cloud points of 0.2% aqueous solutions are between 36 and 46 °C for the diblock copolymers that contain a 50 wt % EO thermoresponsive block and 78 °C for the triblock copolymer that contains a 75 wt % EO thermoresponsive block. Variable temperature ¹H NMR spectra recorded on D₂O solutions of the diblock copolymers display no PLA resonances below the cloud point and fairly sharp PLA resonances above the cloud point, suggesting that desolvation of the thermoresponsive block increases the miscibility of the two blocks. Preliminary characterization of the micelles formed in aqueous solutions of BuO‐(PEO‐stat‐PPO)‐block‐PLA‐OH conducted using laser scanning confocal microscopy and pulsed gradient spin echo NMR point to significant changes in the size of the micellar aggregates as a function of temperature. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5156–5167, 2005     

Nonlinear theory of acoustic wave interaction with laser discharge

The problem of gas laser modulation by acoustic wave is studied theoretically. Theoretical treatment is based on the semiclassical theory of laser and on the theory of acoustic wave propagation in the positive column of d.c. glow discharge. The solution of basic equations is found and the analysis of obtained results is carried out.     

Non-planar smoulder propagation governed by diffusion

The steady propagation of a thin smouldering front in a half-spacehas been considered. A suitable coordinate transformation hasallowed the region near the leading edge of the front to beexamined for both a maintained planar surface and with surfacecollapse due to material shrinkage. The change in the oxidizerconcentration for a small increment in the propagation speedfor large time and surface collapse has been determined. Theinfluence of two types of nonlinear diffusion on the shape ofthe smouldering front has been found; other cases can be dealtwith in a similar manner.     

Low frequency waves in a positive column of discharge

The propagation of longitudinal low frequency waves in the plasma of the positive column of a d.c. glow discharge is studied theoretically. The dispersion characteristics are obtained for conduction, ion acoustic and neutral acoustic waves. Equations are solved numerically and the results are compared with other theories and measurements.     

Self-swept erbium fiber laser around 1.56 μm

Self-swept erbium fiber laser emitting around 1.56?μm is reported in detail. Both sweep directions were registered: pointing toward longer and shorter wavelengths, redshift and blueshift sweeping, respectively. We describe method of determining the direction of the wavelength drift using the monochromator based optical spectrum analyzer. Possible root for this sweeping regime, i.e., the gain modulation along active fiber, is discussed with the help of a simple model calculating the overall cavity gain that can predict the direction of the laser wavelength sweeping.     

Light scattering from a waveguide structure with a sinusoidally corrugated boundary modulated by a weak roughness

Results are reported of the analysis of light scattering from a waveguide structure with a periodically and randomly distorted boundary. The method is based on the assumption of single scattering. The field inside the waveguide is analyzed within the framework of the geometrical optics approach. Results of a computer simulation are presented.