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91.
Paulsen H Antons S Brandes A Lögers M Müller SN Naab P Schmeck C Schneider S Stoltefuß J 《Angewandte Chemie (International ed. in English)》1999,38(22):3373-3375
Seemingly heartbreaking for a stereochemist, the one-step selective construction of a stereopentad and its prompt destruction by aromatization has been proven to be an efficient strategy for the synthesis of fivefold substituted, pharmacologically highly active arenes (see scheme). 相似文献
92.
Assuming that the conduction electrons of an amorphous metal contribute to the binding, we investigate whether a magnetic field will influence the transition from the amorphous to the crystalline state. Measurements taken on amorphous Bi, Ga and Yb films show no change in the crystallization temperatures within an accuracy of ±0.1 K due to a magnetic field of 18.5 T parallel to the surface of the films.Dedicated to Prof. Dr. W. Buckel on the occasion of his 60th birthday 相似文献
93.
The industrial process of coating flat surfaces with polymeric substances is numerically simulated by solving the full equations of motion for a flow through a contraction with a moving boundary. The four-constant Oldroyd constitutive equation is used to represent the viscoelastic fluid. Some adjustments to existing finite-difference methods are made in such a way as to avoid singular iterative matrices during the solution process. Results are presented for flow situations with Weissenberg numbers up to about three times larger than any previously published results for this problem. 相似文献
94.
95.
96.
E. Martini H. Kämmerer H. Fasold F. Kloos M. Fleißner K. Dehnicke O. Fuchs 《Colloid and polymer science》1981,259(8):865-872
Ohne Zusammenfassung 相似文献
97.
98.
V. V. Nesvizhevsky A. K. Petukhov H. G. Börner T. A. Baranova A. M. Gagarski G. A. Petrov K. V. Protasov A. Yu Voronin S. Baeßler H. Abele A. Westphal L. Lucovac 《The European Physical Journal C - Particles and Fields》2005,40(4):479-491
We have studied neutron quantum states in the potential well formed by the earths gravitational field and a horizontal mirror. The estimated characteristic sizes of the neutron wave functions in the two lowest quantum states correspond to expectations with an experimental accuracy. A position-sensitive neutron detector with an extra-high spatial resolution of
m was developed and tested for this particular experiment, to be used to measure the spatial density distribution in a standing neutron wave above a mirror for a set of some of the lowest quantum states. The present experiment can be used to set an upper limit for an additional short-range fundamental force. We studied methodological uncertainties as well as the feasibility of improving further the accuracy of this experiment.Received: 31 July 2004, Published online: 7 March 2005PACS:
03.65, 28.20
Correspondence to: V. Nesvizhevsky 相似文献
99.
A. N. Andreyev D. Ackermann F. P. Heßberger S. Hofmann M. Huyse I. Kojouharov B. Kindler B. Lommel G. Münzenberg R. D. Page K. Van de Vel P. Van Duppen K. Heyde 《The European Physical Journal A - Hadrons and Nuclei》2003,18(1):55-64
Alpha-decay of the new nuclide 184Bi has been studied in the complete-fusion reaction 93Nb(94Mo, 3n)184Bi at the velocity filter SHIP. The evaporation residues were separated in-flight and subsequently identified on the basis of recoil-
, recoil-
-
analysis and excitation functions measurements. Two
-decaying isomeric states in 184Bi with half-life values of 13(2) ms and 6.6(1.5) ms were identified. The
-branching ratio of 180Tl was deduced for the first time as
. Improved data on the fine-structure
-decay of 186Bi were obtained in the 93Nb(95Mo, 2n)186Bi reaction. A similarity of the decay energies and half-life values of 184,186Bi is pointed out and a possible explanation for this effect is suggested.Received: 14 March 2003, Revised: 29 April 2003, Published online: 2 September 2003PACS:
23.60.+e
decay - 27.70.+q
- 27.80.+w
K. Heyde: Present address: EP-ISOLDE, CERN, CH-1211, Geneva 23, Switzerland. 相似文献
100.
Kurt Leichtweiß 《Journal of Geometry》2003,78(1-2):92-121
Analogue to the definition $K + L := \bigcup_{x\in K}(x + L)$ of the
Minkowski addition in the euclidean geometry it is proposed to define the
(noncommutative) addition $K \vdash L := \bigcup_{0\, \leqsl\, \rho\,\leqsl\,
a(\varphi),0\,\leqsl\,\varphi\,<\, 2\pi}T_{\rho}^{(\varphi)}(L)$ for compact,
convex and smoothly bounded sets K and
L in the hyperbolic plane $\Omega$
(Kleins model). Here $\rho = a(\varphi)$ is the representation of the boundary
$\partial$ K in geodesic polar coordinates
and $T_{\rho}^{(\varphi)}$ is the hyperbolic translation of $\Omega$ of length
$\rho$ along the line through the origin o of
direction $\varphi$. In general this addition does not preserve
convexity but nevertheless we may prove as main results: (1) $o \in$ int
$K, o \in$ int L and K,L horocyclic convex imply the strict
convexity of $K \vdash L$, and (2) in this case there exists a hyperbolic mixed
volume $V_h(K,L)$ of K and L which has a representation by a suitable
integral over the unit circle. 相似文献