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101.
Laser drilling of stainless steel with nanosecond double-pulse 总被引:1,自引:0,他引:1
X.D. Wang A. Michalowski D. Walter S. Sommer M. Kraus J.S. Liu F. Dausinger 《Optics & Laser Technology》2009,41(2):148-153
Nanosecond double-pulse laser drilling is reported in this paper. The double-pulse herein represents two closely conjoint pulses with 21 ns pulse duration and about 52 ns interpulse separation, which are acquired by temporal pulse shaping. Percussion drilling with such double-pulse is performed in stainless steel samples with different laser fluences, sample's thickness, repetition rates and ambient pressures. The experimental results show that the drilling rates of double-pulse drilling are more than one order of magnitude higher than that of conventional single-pulse drilling in air. Differences in the processing results between single-pulse and double-pulse with various processing parameters are investigated. In addition the ablation mechanisms of the double-pulse drilling are discussed. 相似文献
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A previously proposed model describing the trapping site of the interstitial atomic hydrogen in borate glasses is analyzed. In this model the atomic hydrogen is stabilized at the centers of oxygen polygons belonging to B–O ring structures in the glass network by van der Waals forces. The previously reported atomic hydrogen isothermal decay experimental data are discussed in the light of this microscopic model. A coupled differential equation system of the observed decay kinetics was solved numerically using the Runge Kutta method. The experimental untrapping activation energy of 0.7×10−19 J is in good agreement with the calculated results of dispersion interaction between the stabilized atomic hydrogen and the neighboring oxygen atoms at the vertices of hexagonal ring structures. 相似文献
103.
A number of recent papers have studied when symmetry causes frameworks on a graph to become infinitesimally flexible, or stressed,
and when it has no impact. A number of other recent papers have studied special classes of frameworks on generically rigid
graphs which are finite mechanisms. Here we introduce a new tool, the orbit matrix, which connects these two areas and provides
a matrix representation for fully symmetric infinitesimal flexes, and fully symmetric stresses of symmetric frameworks. The
orbit matrix is a true analog of the standard rigidity matrix for general frameworks, and its analysis gives important insights
into questions about the flexibility and rigidity of classes of symmetric frameworks, in all dimensions. 相似文献
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Christos Apostolidis Dr. Bernd Schimmelpfennig Dr. Nicola Magnani Dr. Patric Lindqvist‐Reis Dr. Olaf Walter Dr. Richard Sykora Dr. Alfred Morgenstern Dr. Eric Colineau Dr. Roberto Caciuffo Prof. Dr. Reinhardt Klenze Dr. Richard G. Haire Dr. Jean Rebizant Dr. Frank Bruchertseifer Dr. Thomas Fanghänel Prof. Dr. 《Angewandte Chemie (International ed. in English)》2010,49(36):6229-6229
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The crystal structure of [Co(nta)(N,N-Et2en)] (nta = nitrilotriacetate and N,N-Et2en = N,N-diethylethylenediamine) was determined from three-dimensional X-ray diffraction data. The substituted nitrogen of N,N-diethylethylenediamine is bonded trans to the nta nitrogen with the Co—N(N,N Et2en)= 2.011(5) and Co—N(nta) = 1.950(4) Å while the cis Co—N bond is 1.953(4) Å. The Co—O bond lengths are 1.905(2) and 1.884(4) Å respectively. 相似文献