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861.
The possibility of using ultrasonic guided waves for monitoring the cure process of epoxy resins is investigated. The two techniques presented use a wire waveguide which is partly embedded in the resin. The first technique is based on the measurement of attenuation due to leakage of bulk waves into the resin surrounding the waveguide. The second technique measures the reflection of the guided wave that occurs at the point where the waveguide enters the resin. Both the attenuation and the reflection coefficient change significantly during cure, and the numerical methods to relate these to the material properties of the curing resin are presented in this paper. The results from the modeling are experimentally verified and show good agreement. The applicability of each testing method is discussed, and typical cure-monitoring curves are presented. 相似文献
862.
We study the effect of spatially homogeneous and inhomogeneous shadowing on J/psi production in deuterium-nucleus collisions. We discuss how the shadowing and its spatial dependence can be measured by comparing central and peripheral dA collisions. These event classes may be selected by using gray protons from heavy ion breakup and events where the proton or neutron in the deuterium does not interact. We find that inhomogeneous shadowing has a significant effect on central dA collisions, larger than expected in central AA collisions. Results are presented for dAu collisions at sqrt[s(NN)]=200 GeV and dPb collisions at sqrt[s(NN)]=6.2 TeV. 相似文献
863.
K. Aggarwal L. Asch F. N. Gygax O. Hartmann G. M. Kalvius A. Kratzer F. J. Litterst K. Mattenberger A. Schenck O. Vogt 《Hyperfine Interactions》1989,51(1-4):933-942
The materials crystallize in the NaCl structure. UP undergoes at 122 K a first order transition into a type I single-k antiferromagnetic
state, followed by a second first order transition into a type I double-k-structure at 22 K. UTe is a ferromagnet withT
c
=104 K. The two first order transitions of UP reveal themselves by abrupt changes of the transverse field damping rate. No
spin rotation is observed in zero field for both antiferromagnetic spin structures which is in keeping with point dipolar
lattice sums. In UTe we observe the characteristic critical behavior: a rapid increase of damping rate and paramagnetic frequency
shift when approachingT
c
from above. In the ferromagnetic regime the spin rotation in zero field damps out too rapidly to be observed.
This work has been funded in part by the German Federal Minister for Research and Technology (BMFT) under contract Nr. 03-KA1-TUM-4. 相似文献
864.
865.
V. V. Ammosov D. S. Baranov V. I. Ermolaev A. A. Ivanilov P. V. Ivanov V. I. Konyushko V. M. Korabliev V. A. Korotkov V. A. Krupnov V. V. Makeev A. G. Myagkov A. Yu. Polyarush A. A. Sokolov E. P. Kuznetsov H. -J. Grabosch H. H. Kaufmann U. Krecker R. Nahnhauer S. Nowak S. Schlenstedt H. Vogt 《Zeitschrift fur Physik C Particles and Fields》1986,30(4):569-574
Using the freon filled bubble chamber SKAT in the (anti)neutrino wide band beam of the Serpukhov accelerator we determine the neutral to charged current cross section ratios for neutrinos and antineutrinos below 30GeV. From these ratios we calculate in leading order a mixing parameter of the standard model of Θ w =0.215±0.029. 相似文献
866.
867.
868.
869.
The gluon and sea distributions of the pion are uniquely determined by the requirement of avalence-like structure of the input parton distributions at some low resolution scale. These (dynamical) results are obtained with practically no free parameters, just using the experimentally determined pionic valence distribution combined with the constraints for the pionic gluon distribution provided by direct-γ data. Simple parametrizations of the resulting parton distributions are presented in the range 10?5?x<1 and 0.3?Q 2?108 GeV2 as obtained from the leading-and higher-order evolution equations. 相似文献
870.