Buchbesprechungen

Ohne Zusammenfassung     

Ten years (1986–1995) of lidar observations of temporal and vertical structure of stratospheric aerosols over Siberia

The data of laser sensing of the vertical aerosol distribution obtained at Siberian Lidar Station of the Institute of Atmospheric Optics, Tomsk (56.5°N, 85.1°E), Russia in 1986–1995 are analyzed. The data are presented in the form of the scattering ratio R(H), the aerosol backscattering coefficient β^a_π(H), and the integrated aerosol backscattering coefficient between 15 and 30 km Σβ^a_π at the wavelength λ=532 nm. During the period from summer 1986 to summer 1991, Σβ^a_π varied in the range 0.8×10^-4–3×10^-4 sr^-1. Average profiles of R(H) and β^a_π(H) for the main seasons, the annual behaviour of the altitude of the peak scattering ratio and of the tropopause height, and the eigenvectors of the correlation matrix of R(H) are also presented for this period. In succeeding years, the behavior of the stratospheric aerosol layer (SAL) was primarily determined by the Pinatubo volcanic aerosol. Based on an analysis of the scattering ratio profiles, the formation of the vertical volcanic aerosol stratification above Tomsk is demonstrated. The maximum values of Σβ^a_π≈4×10^-3 sr^-1, caused by the volcanic aerosol, were observed in January–February 1992. Between 15 and 30 km, the 1/e-decay time of the stratospheric volcanic aerosol was 357±37 days. Lidar measurements carried out on certain days simultaneously at λ=532, 353, and 628 nm allowed us to investigate the transformation of the exponent A(H) that characterizes the spectral dependence of the volcanic aerosol backscattering coefficient in the wavelength range 353–532 nm and to estimate the geometric cross section of particles S(r).     

Estimating dimensions of flaws with narrow openings along the beam direction

The problem of flaw dimension measurement along the beam direction is discussed from the viewpoint of the measurement accuracy. Practical recommendation are put forth for estimating dimensions of flaws with small openings, such as incomplete fusions in welded joints, along the beam direction using X-ray photographs.     

Informationstagung Mikroelektronik 1999

Ohne Zusammenfassung     

Hydroxyl radical-induced hydrogen/deuterium exchange in amino acid carbon-hydrogen bonds

BB rats are used as models of autoimmune human IDDM. Genetic control of IDDM in both species is complex, including both major histocompatibility complex (MHC)-linked and non-MHC-linked genes. DP-BB rats develop IDDM spontaneously. Expression of disease in these animals requires homozygosity at the lyp locus, which causes lymphopenia. All genetic analyses of BB rat diabetes to date have backcrossed to the DP-BB strain or used (DP-BB x non-BB)F2 animals to ensure that a fraction of progeny are homozygous for lyp. Here we report the analysis of a backcross of the DP-BB rat to the histocompatible WF rat. Neither WF nor (WF x DP-BB)F1 animals develop spontaneous IDDM. However, 95% of (WF x DP-BB)F1 rats and a fraction of (WF x DP-BB) x WF backcross animals readily develop IDDM after treatment with polyinosinic:polycytidylic acid and a cytotoxic anti-RT6.1 monoclonal antibody. Using simple sequence length polymorphism analysis, we have mapped loci on chromosomes 4 and 13 that show significant linkage to IDDM expression and insulitis. The susceptibility locus on chromosome 4 is linked to, but not identical to, lyp. We propose a disease model for the BB rat that requires 1) the RT1u MHC haplotype for disease susceptibility, 2) a new locus on chromosome 4 for disease initiation (as measured by insulitis), 3) a new locus on chromosome 13 for disease progression in response to environmental perturbation, and 4) lyp for spontaneous expression of disease.     

Ein schnell messendes Laser-Speckle-Extensometer zur Bestimmung von statischen und dynamischen Materialparametern

In order to increase the measurement rate of so far in use laser straining sensors an absolutely new type of sensors has been developed. These sensors are based on Fourier optical data pre-processing. In this paper advantages and disadvantages of these Fourier optical sensors are discussed.