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1.
2.
Peter Karduck Norbert Ammann Hans Günter Esser Jörg Winter 《Fresenius' Journal of Analytical Chemistry》1991,341(5-6):315-319
Summary The first wall of the fusion device TEXTOR at the Forschungszentrum Jülich has been coated in situ with an amorphous hydrogen rich carbon/boron film (a-C/B:H) which reduces plasma impurities caused by the plasma surface interaction. The results of the coating process of the 35 m2 large inner wall surface have been controlled by a recently developed modification of the quantitative electron probe microanalysis, which has been applied to 12 samples from specified positions inside the tokamak. The quantification itself is based on a Monte Carlo simulation of electron trajectories providing very accurate results for X-ray intensities emitted by elements present in the electron bombarded sample. The Monte Carlo results are used in the present work to calibrate the measured X-ray intensities emitted by boron and carbon from the a-C/B:H layers deposited on pure silicon substrates. As a result the total deposited mass of the layer per area unit as well as the composition of the layers (except hydrogen) could be determined very accurately. The relative errors were less than 7%. The limit of detectability were found to be in the range of one monolayer for boron as well as for carbon. 相似文献
3.
4.
The projected areas of non-spherical particles do not represent an unambiguous particle characteristic. Depending on the orientation towards a constant observational direction, different projected areas result. The spectrum of all projected area values of a particle, if determined representatively, gives the probability with which a certain value is obtained by a single measurement. In this work, the frequency distributions of different examples of test objects were both calculated and measured. The objects were a cube, a rectangular parallelepiped and also three model agglomerates consisting of spheres of the same size. Instead of just one projected area, during each measuring procedure three projected areas from three orthogonal directions can be obtained. A mean value is then calculated to reduce the ambiguity of the particle characteristic and enhance the resolution. A suitable measurement set-up is introduced. The results of calculation and measurement are compared for observation from just one direction and also simultaneous observation from three directions. The frequency distributions of the equivalent diameters of the particle projected areas show a characteristic trend of the total curve with remarkable properties. The simultaneous measurement of three values from mutually orthogonal directions and their mean value calculation result in a much narrower distribution. In this case, a non-sphericity factor can additionally be calculated, whose frequency distribution contains information in a characteristic manner about the degree to which the particle shape differs from a sphere. 相似文献
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6.
Andreas Spillner 《Mathematical Logic Quarterly》2006,52(1):29-36
We study the problem of tiling a polyomino P with as few squares as possible such that every square in the tiling has a non‐empty intersection with the boundary of P . Our main result is an algorithm which given a simply connected polyomino P computes such a tiling of P . We indicate how one can improve the running time of this algorithm for the more restricted row‐column‐convex polyominoes. Finally we show that a related decision problem is in NP for rectangular polyominoes. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
7.
F. Seiffert R. Schwengner G. Winter L. Funke W. Lieberz R. Reinhardt K. P. Schmittgen D. Weil R. Wrzal K. O. Zell P. von Brentano 《Zeitschrift für Physik A Hadrons and Nuclei》1991,340(2):141-153
Excited states of73Se have been investigated up to spin, 21/2 using techniques of in-beamγ-ray spectroscopy in connection with the70Ge(α, n) reaction. Mean lifetimes of 12 levels have been determined applying Doppler-shift andγ-RF-methods. Five different bands have been identified that reflect a variety of different excitation modes. The decoupled 9/2+ band is likely to correspond to an oblate deformation while the 5/2+ band is interpreted as a strongly coupled prolate band built on the Nilsson configuration [422] 5/2+. The 3/2? band is a strongly coupled band built on the [301] 3/2} configuration.Nuclear reactions:70Ge(α,n),E=14, 16, 18, 19, 20MeV; measuredE γ,I γ,σ(E γ,θ),γγ-coin, linear polarization, DSA,γ(t).75Se deduced levels,I, π, τ, δ(E2/M1), B(σλ). Enriched targets, Ge detectors. 相似文献
8.
H. Winter 《Zeitschrift für Physik B Condensed Matter》1993,91(3):343-349
We discuss how to use KKR bandstructure to evaluate the density-density correlation function in DFA (density functional) — RPA approximation without introducing adjustable parameters. We stress the importance to determine the dielectric function to a high degree of accuracy in the high frequency range to guarantee the fulfillment of the f-sum rule. Results for Vanadium as a typical example of a transition metal are presented and compared to experiment. 相似文献
9.
John R. Peterson Tamara J. Winter Hoang D. Do Robin D. Rogers 《Journal of chemical crystallography》1989,19(1):135-145
Structural and conformational information obtained from the crystal structure and solution1H nmr investigations of the title compound are compared. The 4-aryltetralone, C24H24O10, crystallizes as a chloroform solvate in the monoclinic space group, P21/n, witha=12.519(4),b=17.938(6),c=12.534(9)Å,=111.90(5)°, and Dcalc=1.51 g cm–3 forZ=4. The data for this compound were collected at –150°C. Least-squares refinement of 2796 observed [F
o5(F
o)] reflections led to the final agreement index ofR=0.062. A threefold static disorder was observed for one of the carboxyl groups. The second carboxyl group participates in an intramolecular hydrogen bond and is thus ordered. The1H nmr spectrum revealed the title compound to exist as a keto-enol tautomeric mixture in solution. Vicinal hydrogen coupling constant analysis proved reliable in ascertaining B-ring stereochemistry of 2,3-disubstituted-4-aryltetralones. 相似文献
10.
Andreas Floer 《Communications in Mathematical Physics》1988,118(2):215-240
To an oriented closed 3-dimensional manifoldM withH
1(M, )=0, we assign a 8-graded homology groupI
*(M) whose Euler characteristic is twice Casson's invariant. The definition uses a construction on the space of instantons onM×. 相似文献