Experimental and theoretical comparison of spatially resolved laser-induced incandescence (LII) signals of soot in backward and right-angle configuration

In-situ measurements of soot volume fraction in the exhausts of jet engines can be carried out using the laser-induced incandescence (LII) technique in backward configuration, in which the signal is detected in the opposite direction of the laser beam propagation. In order to improve backward LII for quantitative measurements, we have in this work made a detailed experimental and theoretical investigation in which backward LII has been compared with the more commonly used right-angle LII technique. Both configurations were used in simultaneous visualization experiments at various pulse energies and gate timings in a stabilized methane diffusion flame. The spatial near-Gaussian laser energy distribution was monitored on-line as well as the time-resolved LII signal. A heat and mass transfer model for soot particles exposed to laser radiation was used to theoretically predict both the temporal and spatial LII signals. Comparison between experimental and theoretical LII signals indicates similar general behaviour, for example the broadening of the spatial LII distribution and the hole-burning effect at centre of the beam due to sublimation for increasing laser pulse energies. However, our comparison also indicates that the current heat and mass transfer model overpredicts signal intensities at higher fluence, and possible reasons for this behaviour are discussed. PACS 42.62.Fi; 44.40.+a     

Contribution to the Analysis of theA2←XA1“Wulf” Transition of Ozone by High-Resolution Fourier Transform Spectrometry

The analysis of the rotational structure of the high-resolution Fourier transform 0⁰₀absorption spectrum of the³A₂←X¹A₁band system of the “Wulf” transition of the isotopomer¹⁶O₃of ozone is reported for the first time. With a near pure case (b) coupling model for the upper triplet state, we have assigned a significant portion of the spectrum, mainly theF₁(J=N+ 1) andF₂(J=N) spin components, primarily in the lower frequency region of the band. The lines corresponding to theF₃(J=N− 1) component are weak at lower frequencies and heavily congested in the central and higher frequency regions of the spectrum. Perturbations and predissociation phenomena have reduced the effective lifetime of the metastable³A₂state and have also limited the number of transitions included in the least-squares fit of the band. Approximately 100 lines have been assigned in the range from 9100–9550 cm⁻¹. Three rotational, three centrifugal distortion, three spin–rotation, and one spin–spin constant were varied. The geometry of the molecule in the³A₂state, as determined from these constants, isr= 1.345 Å and θ = 98.9°, in good agreement withab initioresults.     

Biotin grafting on boron-doped diamond

Grafting of biotin on top of a polycrystalline boron-doped diamond layer was achieved by surface oxidation followed by an esterification reaction and revealed by fluorescently labelled streptavidin.     

Prime ideals in polynomial rings

Summary Study of relations between the prime and maximal spectra of a ringA and ofA[X], without noetherian assumptions. Application to the cases whereA has finite noetherian type andA is an arbitrary valuation domain; behaviour of the catenary property. New proofs of known results aboutG-ideals and Hilbert domains.

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Riassunto Si studiano le relazioni fra lo spettro ideale e quello massimale di un anelloA e diA[X] senza ipotesi di noetherianità. Si fanno delle applicazioni ai casi in cuiA è un anello di tipo noetheriano finito o è un arbitrario dominio di valutazione; si studia inoltre il comportamento della proprietà catenaria. Si danno nuove dimostrazioni di risultati noti suG-ideali e domini di Hilbert.

     

A deconvolution technique for B-dot signals from aplasma-driven electromagnetic launcher

A novel technique is being developed to quantify the current distribution in the plasma armature of an electromagnetic launcher (EML). The technique relies on data from B-dot probes inserted above the barrel of an EML. The current distribution is found by taking the fast Fourier transform of the integral of the B-dot signal and deconvolving it with a geometry-dependent weight function. The result allows calculation of the total plasma length and total current magnitude. The author describes the signal-analysis technique, discusses results obtained from theoretical B-dot signals, and suggests possible sources of error which may be encountered when deconvolving experimental B-dot signals     

Neue Alkalimetall‐halogenopalladate(II) mit Iodeinlagerung — Kristallstrukturen,Phasenübergänge und Spektroskopie

New Alkaline Halogenopalladates(II) with Incorporated Iodine Dumb‐Bells — Crystal Structures, Phase‐Transitions, and Vibrational Spectra Dark‐reddish crystals of Cs₂[PdBr₄]I₂, Cs₂[PdCl₄]I₂, and black crystals of Rb₂[PdBr₄]I₂ were obtained by solvothermal reaction from diluted hydrohalogenic acids and crystallize in space group I4/mmm with Z = 2. Unitcell parameters for Cs₂[PdBr₄]I₂ are a = 848.96(1) pm, c = 908.53(2) pm; Cs₂[PdCl₄]I₂ a = 814.65(2) pm, c = 899.10(1) pm and for Rb₂[PdBr₄]I₂ a = 840.9(1) pm, c = 902.3(1) pm. The compounds contain isolated [PdX₄] building units (X = Cl, Br) which are supplemented by embedded iodine dumb‐bells. Cs₂[PdBr₄]I₂ and Cs₂[PdCl₄]I₂ show reversible pressure induced phase transitions above 78 kbar and 199 kbar, respectively.