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991.
992.
Inside Cover: Reversible 1,1‐Hydroboration: Boryl Insertion into a CN Bond and Competitive Elimination of HBR2 or RH (Angew. Chem. Int. Ed. 18/2015) 
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下载免费PDF全文 993.
994.
995.
We discuss the electron pair emission from surfaces upon the absorption of a single photon, also called double photoemission (DPE). This experiment is particular sensitive to the electron–electron interaction, because for independent electrons the DPE intensity is zero. We outline the experimental development of this technique over the past decade. Going beyond the mere detection of pairs we advanced the instrumentation. Now we are able to measure the kinetic energies and emission angles of a wide angular acceptance. We will show how the available energy is distributed among the electrons and how the angular distributions look like. The latter enabled us to make contact to an important concept of modern solid state theory, namely the exchange–correlation hole. We demonstrate that the exchange–correlation hole manifests itself in a depletion zone of the coincidence intensity around the fixed emission direction of one electron. The experiments were performed at the synchrotron facilities BESSY I and BESSY II. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
996.
997.
Abstract Based on an experimental investigation of nitrogen concentrations and δ15N-values in different parts of Picea abies (L.) trees and soil samples and of their dependence on the age of plant parts and on damaging stress, mathematical models which represent main features of nitrogen turnover in the forest tree - soil system and associated isotope variations are developed. These models consider parts of 3 cycles of nitrogen: (1) transport of soluble nitrogen within trees, (2) turnover of protein nitrogen in different plant parts, and (3) the exchange of N between tree and soil via litter and the uptake of mineralized soil N by plant roots. Isotope effects of protein synthesis and mineralization of organic soil N are included. The models give a qualitative explanation of the data and lead to a better understanding of isotopic variations as indicators of forest damage. 相似文献
998.
M. Winkler S. Gammino G. Ciavola L. Celona P. Spädtke K. Tinschert 《辐射效应与固体损伤》2013,168(10-12):535-543
The new generation of ion sources delivers beams with intensities of several mA. This requires a careful design of the analysing system and the low-energy beam transport (LEBT) from the source to the subsequent systems. At INFN-LNS, high intensity proton sources (TRIPS [L. Celona, G. Ciavola, S. Gammino et al., Rev. Sci. Instrum. 75(5) 1423 (2004)], PM-TRIPS [G. Ciavola, L. Celona, S. Gammino et al., Rev. Sci. Instrum. 75(5) 1453 (2004)]) as well as ECR ion sources for the production of highly charged high-intensity heavy ion beams are developed (SERSE [S. Gammino, G. Ciavola, L. Celona et al., Rev. Sci. Instrum. 72(11) 4090 (2001), and references therein], GyroSERSE [S. Gammino et al., Rev. Sci. Instrum. 75(5) 1637 (2004)], MS-ECRIS [G. Ciavola et al., (2005), 11th Int. Conf. on Ion Sources, Caen, (in press)]). In this paper, we present ion-optical design studies of various LEBT systems for ion-sources devoted to the production of intense beams. Calculations were performed using the computer codes GIOS [H. Wollnik, J. Brezina and M. Berz, NIM A 258 (1987)], GICO [M. Berz, H.C. Hoffmann, and H. Wollnik, NIM A 258 (1987)], and TRANSPORT [K.L. Brown, F. Rothacker and D.C. Carey, SLAC-R-95-462, Fermilab-Pub-95/069, UC-414 (1995)]. Simulations take into account the expected phase space growth of the beam emittance due to space-charge effects and image aberrations introduced by the magnetic elements. 相似文献
999.
A. X. Trautwein P. Wegner H. Winkler H. Paulsen V. Schünemann C. Schmidt A. I. Chumakov R. Rüffer 《Hyperfine Interactions》2005,165(1-4):295-298
Nuclear inelastic scattering in conjunction with density functional theory (DFT) calculations has been applied for the identification
of vibrational modes of the high-spin ferric and the high-spin ferrous iron–sulfur center of a rubredoxin-type protein from
the thermophylic bacterium Pyrococcus abysii. 相似文献
1000.
Björn Winkler Karsten Knorr Victor Milman Miguel Avalos 《Journal of Physics and Chemistry of Solids》2003,64(3):405-411
The structures, bonding and relative thermodynamic stabilities of the crystalline molybdenum phosphides Mo3P, Mo8P5, Mo4P3, MoP, MoP2, MoP4, have been investigated by density functional theory calculations. The elastic stiffness coefficients for MoP and MoP2 have been predicted. 相似文献