Two wavelength-CARS thermometry of hydrogen

In this work, we present the results of two-wavelength (2)-CARS thermometry of hydrogen at temperatures from 300–1200 K. The choice of the pair of spectral lines for the 2-CARS thermometer with respect to optimal temperature sensitivity within a given temperature range was analysed. Software was developed to process the experimental data and calculate the temperature. In the experiments, temperature and density were measured in a heated cell using single-shot and averaged CARS intensities in the pure rotationalS branch. The accuracy achieved and its dependence on measured temperature values and on the number of averaged shots was analysed.The sponsoring of this work by the Stabsabteilung Internationale Beziehungen at the Kernforschungszentrum Karlsruhe under project number RUS 222.12 is gratefully acknowledged     

Discrete Toda lattices and the Laplace method

We apply the Laplace cascade method to systems of discrete equations of the form u _i+1,j+1 = f(u _i+1,j , u _i,j+1, u _i,j , u _i,j?1), where u _ij , i, j ∈ ?, is an element of a sequence of unknown vectors. We introduce the concept of a generalized Laplace invariant and the related property that the systems is “of the Liouville type.” We prove a series of statements about the correctness of the definition of the generalized invariant and its applicability for seeking solutions and integrals of the system. We give some examples of systems of the Liouville type.     

Formation of Structural-Phase States in Alumina Ceramics VK-95 by Sintering in a Constant Magnetic Field

Russian Physics Journal -     

Synthesis and properties of nitro-1,2,3-triazoles (Review)

Published data on methods for the synthesis of substituted 4(5)-nitro-1,2,3-triazoles and their properties are reviewed. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 3–25, January, 2008.     

Integrable boundary problems for 2D Toda lattice

Spatially two-dimensional Toda lattice is examined in the aspect of correct formulation of boundary problems that can be solved within the scheme of the Inverse Scattering Method. It is shown that there exists a large set of integrable boundary problems and various curves can be chosen as boundaries for those problems. Explicit solutions are presented for problems on closed and unclosed curves taken as boundary contours.     

Single‐shot CARS thermometry of high‐pressure hydrocarbon flames using simultaneous intensity and linewidth measurements

We demonstrate the feasibility of single laser shot coherent anti‐Stokes Raman scattering thermometry with simultaneous measurement of intensities of hydrogen Q‐branch lines and their linewidths in a pulsed CH₄/O₂ combustion chamber operating at 20 MPa pressure and 3000 K temperature—parameters that are typical for full‐scale rocket engines. The measurements were done by means of a spectrograph combined with an interferometer having orthogonal directions of dispersions. This approach allows correct temperature evaluation that takes into account the directly measured linewidths. Copyright © 2010 John Wiley & Sons, Ltd.     

Dual-broadband CARS temperature measurements in hydrogen-oxygen atmospheric pressure flames

Dual-broadband coherent anti-Stokes Raman scattering (CARS) spectroscopy of the Q₀₁-branch of H₂ has been employed for thermometry in an atmospheric-pressure hydrogen-oxygen flame. The aim was to investigate the applicability of the technique for single-shot temperature evaluation and to analyse the precision of the measurements. The results are presented of temperature and relative H₂ density mapping of the flame in the temperature range of 700-2800 K. The achieved precision of single-shot measurements was 3-5%.     

The analysis of the precision of single shot 2λ-CARS temperature measurements in hydrogen

Received: 16 October 1996/Revised version: 17 March 1997     

CARS temperature measurement in a LOX/CH4 spray flame

Coherent anti‐Stokes Raman scattering (CARS) spectroscopy has been used to investigate cryogenic liquid oxygen/gaseous methane (LOX/CH₄) flames on a medium‐size test facility at a pressure of 0.24 MPa and mass flow of 0.025 kg/s. Single‐shot, broadband CARS spectra with simultaneous detection of the Q‐branches of hydrogen and water molecules were recorded with good signal‐to‐noise ratio. Temperature was deduced from the H₂ and H₂O CARS profiles. The spatial temperature distribution in a comparatively harsh environment has been measured successfully. The measurements took place in the windowed combustion chamber of the DLR M3 test facility, aiming to provide data for validation of rocket combustor modeling. Copyright © 2010 John Wiley & Sons, Ltd.