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91.
92.
Lidar calibration experiments 总被引:2,自引:0,他引:2
Hans E. Jørgensen Torben Mikkelsen Jürgen Streicher Hartmut Herrmann Christian Werner Erik Lyck 《Applied physics. B, Lasers and optics》1997,64(3):355-361
A series of atmospheric aerosol diffusion experiments combined with lidar detection was conducted to evaluate and calibrate
an existing retrieval algorithm for aerosol backscatter lidar systems. The calibration experiments made use of two (almost)
identical mini-lidar systems for aerosol cloud detection to test the reproducibility and uncertainty of lidars. Lidar data
were obtained from both single-ended and double-ended lidar configurations. A backstop was introduced in one of the experiments
and a new method was developed where information obtained from the backstop can be used in the inversion algorithm. Independent
in-situ aerosol plume concentrations were obtained from a simultaneous tracer gas experiment with SF, and comparisons with the two lidars were made. The study shows that the reproducibility of the lidars is within 15%, including
measurements from both sides of a plume. The correspondence with in-situ measurements is excellent. Finally, the new backstop
method is able to reveal information which can close the lidar equation by obtaining the relation between backscatter and
extinction in an aerosol cloud.
Received: 21 December 1995 / Revised version: 25 July 1996 相似文献
93.
Charles J. K. Batty Ola Bratteli Palle E. T. Jørgensen Derek W. Robinson 《Journal of Geometric Analysis》1995,5(4):427-443
We establish that heat diffusion with periodic conductivity is governed by two scales. The small time diffusion is described by the geodesic distance but the large time behaviour is dictated by the distance associated with an homogenized system obtained by a suitable averaging process. Our methods are quite general and apply to diffusion on a stratified Lie group. 相似文献
94.
E. Dockner G. Feichtinger S. Jørgensen 《Journal of Optimization Theory and Applications》1985,45(2):179-197
This paper identifies some classes ofN-person nonzero-sum differential games that are tractable, in the sense that open-loop Nash strategies can be determined, either explicitly or qualitatively in terms of a phase-diagram portrait. The classes are characterized by conditions imposed on the Hamiltonians. Also, the underlying game structures needed to satisfy these conditions are characterized.The authors wish to thank V. Kaitala, Helsinki University of Technology, and the referees. 相似文献
95.
A simple and versatile pneumatically-operated two-layer rotary valve is described for simultaneous introduction of sample and diversion of analytical streams in flow injection analysis. Examples of application include valve configuration with time-controlled sample volume and with loop-controlled sample volumes in one or two loops; both configurations are useful in routine analyses of samples of highly varying analyte concentrations. The usefulness of the valve for ion-exchange preconcentration procedure is also demostrated. 相似文献
96.
97.
Palle E. T. Jørgensen 《Semigroup Forum》1991,43(1):263-290
We find the invariant convolution semigroups of measures on the Heisenberg group which are analogous to the familiar semigroups
in the abelian context from modern potential theory, and we show that the abelian theory may be obtained as the limit of the
Heisenberg case as Planck's constant tends to zero.
Work supported in part by the NSF. 相似文献
98.
We find the automorphisms and the spectra of several different topological convolution algebras of C∞-functions on the real line. Starting with the convolution algebra of compactly supported C∞-functions, equipped with the usual LF-topology, we define a corresponding convolution algebra of C∞-functions of arbitrarily fast exponential decay at ∞; and convolution algebras of a given finite degree r of exponential decay at ∞. These algebras may be described topologically as “hyper Schwartz spaces.” With a natural Frechet topology, which we define, they get a structure as locally m-convex algebras. The continuous automorphisms and spectra of these algebras are described completely. We show that the algebra of C∞-functions of infinitly fast exponential decay at ∞, , on the one hand, and the algebra of C∞-functions of only a finite degree decay at ∞, r0, on the other hand, have quite different automorphisms, although = ∩rr0. As an application, we show that the conformal group is canonically represented as the full group of automorphisms of r0, and that this representation does not extend to a representation on the Banach algebra L1(). 相似文献
99.
100.
C. Budtz-Jørgensen P. Guenther A. Smith J. Whalen W. R. McMurray M. J. Renan I. J. van Heerden 《Zeitschrift für Physik A Hadrons and Nuclei》1984,319(1):47-56
Neutron total, scattering and (n; n′,γ) cross sections of elemental yttrium (89Y) were measured in the few-MeV region. The neutron total-cross-section measurements were made with broad resolutions from ≈0.5 to 4.2MeV in steps of ?0.1 MeV. Neutron elastic- and inelastic-scattering cross sections were measured from ≈1.5 to 4.0 MeV, at incident-neutron energy intervals of ≈50keV and at ten or more scattering angles distributed between 20 and 160 degrees using neutron detection. Inelastic-scattering cross sections were also determined using the (n; n′,γ) reaction at incident energies from 1.6 to 3.8 MeV at intervals of 0.1 MeV. Gamma-rays and/or inelastically-scattered neutrons were observed corresponding to the excitation of levels at: 909.0±0.5, 1,507.4 ±0.3, 1,744.5±0.3, 2,222.6±0.5, 2,530±0.8, 2,566.4±1.0, 2,622.5±1.0, 2,871.9 ±1.5, 2,880.6±2.0, 3,067.0±2.0, 3,107.0±2.0, 3,140.0±2.0, 3,410.0±2.0, 3,450.0±2.0, 3,504.0 ±1.5, 3,514.0±2.0, 3,556.0±2.0, 3,619.0±3.0, 3,629.0±3.0 and 3,715.0±3.0 keV. The experimental results are discussed in terms of the spherical-optical-statistical, coupledchannels, and core-coupling models, and in the context of previously reported excitedlevel structure. 相似文献