Electrode effects on the neutron spectrum of a plasma focus

End-on neutron spectra of a plasma focus were measured by the time-of-flight method. Using an inner electrode with a specially shaped cavity instead of the normal solid or hollow electrodes caused the maximum of the neutron spectrum to shift from 2.66 MeV to 2.85 MeV. It is attempted to explain the effect by the interaction of the electrode, or the impurities emitted by it, with the compressed plasma.     

Reconstruction of multiply-scattered arrivals from the cross-correlation of waves excited by random noise sources in a heterogeneous dissipative medium

Imagining a medium composed of an arbitrary distribution of point-like heterogeneities, we study the reconstruction of scattered waves in Green's function derived from the cross-correlation function of waves excited by random noise sources of which the distribution is stationary and homogeneous. We show that the reconstruction process is intimately related to generalized forms of the optical theorem. The role of absorption in the formulation of the theorem is discussed. The reconstruction of multiply-scattered arrivals from the cross-correlation of two random wavefields is demonstrated to all orders of scattering for the simple case of two point scatterers, through application of the optical theorem for a single scatterer. In the case of N point scatterers, the cross-correlation of two Green's functions is expressed in the form of Feynman-like diagrams. The wavepaths that contribute to the reconstruction of an arbitrary multiply-scattered arrival of Green's function are identified. Repeated application of the generalized optical theorem, formulated as a diagrammatic rule, demonstrates the destructive interference between all spurious multiply-scattered arrivals.     

Photoinduced pH drops in water

A 2-hydroxyazobenzene platform has been evaluated to photorelease protons in aqueous solutions. Three different systems relying on molecular, supramolecular and polymeric strategies have been investigated in order to tune the water solubility and the thermodynamic and kinetic properties. This paper first reports on the syntheses and the physico chemical analyses for each system. Subsequently, we show that the three strategies are appropriate to reversibly photo-generate tunable pH drops in water up to one pH unit amplitude and at the 10-100 s timescale, upon transient illumination at 365 nm.     

Aminoborylation/Suzuki-Miyaura tandem cross coupling of aryl iodides as efficient and selective synthesis of unsymmetrical biaryls

Sequential borylation of a first aryl iodide using a dialkylaminoborane followed by a Suzuki-Miyaura cross coupling of second aryl iodide ended up with an efficient, selective and practical synthesis of unsymmetrical biaryls. This tandem coupling shows a wide range of applicability.     

High resolution Fourier transform spectroscopy of HD16O: Line positions,absolute intensities and self broadening coefficients in the 8800–11,600 cm−1 spectral region

High-resolution water vapor absorption spectra have been measured at room temperature in the 8800–11,600 cm^?1 spectral region. They were obtained using the mobile BRUKER IFS 120M Fourier transform spectrometer (FTS) from ULB-SCQP coupled to the 50 m base long multiple reflection White type cell in GSMA laboratory. The absorption path was 600 m and different H₂O/HDO/D₂O mixtures were used. Measurements of line positions, intensities and self-broadening coefficients were performed for the HD¹⁶O isotopologue. 6464 rovibrational assignment of the observed lines was made on the basis of global variational predictions and allowed the identification of new energy levels. 3ν₃, 2ν₁+ν₃, 3ν₁+ν₂, ν₁+2ν₃ and 2ν₂+2ν₃ are the five strongest bands. The present paper provides a complementary data set on water vapor for atmospheric and astrophysical applications.     

A solid-state NMR investigation of the structure of mesoporous silica nanoparticle supported rhodium catalysts

A detailed study of the chemical structure of mesoporous silica catalysts containing rhodium ligands and nanoparticles (RhP-MSN) was carried out by multi-dimensional solid-state NMR techniques. The degree of functionalization of the rhodium–phosphinosilyl complex to the surface of the RhP-MSN channels was determined by ²⁹Si NMR experiments. The structural assignments of the rhodium–phosphinosilyl complex were unambiguously determined by employing the novel, indirectly detected heteronuclear correlation (¹³C–¹H and ³¹P–¹H idHETCOR) techniques, which indicated that oxidation of the attached phosphinosilyl groups and detachment of Rh was enhanced upon syngas conversion.     

Suppression of tritium retention in remote areas of ITER by nonperturbative reactive gas injection

A technique based on reactive gas injection in the afterglow region of the divertor plasma is proposed for the suppression of tritium-carbon codeposits in remote areas of ITER when operated with carbon-based divertor targets. Experiments in a divertor simulator plasma device indicate that a 4 nm/min deposition can be suppressed by addition of 1 Pa·m3 s?1 ammonia flow at 10 cm from the plasma. These results bolster the concept of nonperturbative scavenger injection for tritium inventory control in carbon-based fusion plasma devices, thus paving the way for ITER operation in the active phase under a carbon-dominated, plasma facing component background.