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991.
Fischer KH Schneider M Fischer I Pfaffinger B Braunschweig H Sztáray B Bodi A 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(15):4533-4540
The borylene complex [(OC)(5)Cr=B=N(SiMe(3))(2)] has been investigated by using threshold photoelectron-photoion coincidence spectroscopy with synchrotron radiation. The ionization energy of the parent complex and the 0?K appearance energies of the sequential CO loss channels have been determined. The derived bond-dissociation energies are used to discuss bonding and energetics in this compound. 相似文献
992.
The establishment and spreading of biological populations depends crucially on population growth at low densities. The Allee effect is a problem in those populations where the per capita growth rate at low densities is reduced. We examine stochastic spatial models in which the reproduction rate changes across a gradient g so that the population undergoes a 2D-percolation transition. Without the Allee effect, the transition is continuous and the width w of the hull scales as in conventional (i.e., uncorrelated) gradient percolation, w ∝ g(-0.57). However, with a strong Allee effect the transition is first order and w ∝ g(-0.26). 相似文献
993.
Corrigendum: Formation and Fragmentation of Protonated Molecules after Ionization of Amino Acid and Lactic Acid Clusters by Collision with Ions in the Gas Phase 下载免费PDF全文
994.
Marina Cornejo Bashkim Ziberi Christoph Meinecke Dietmar Hirsch Jürgen W. Gerlach Thomas Höche Frank Frost Bernd Rauschenbach 《Applied Physics A: Materials Science & Processing》2011,102(3):593-599
This report focuses on the effect of simultaneous Fe incorporation in the self-organized pattern formation on Si(001) by low-energy
ion-beam sputtering. Experimental observations giving evidence for the correlation between different ion-beam parameters,
Fe concentration on the substrate, and the resulting topography are shown. It was observed that the incorporation of Fe affects
the evolution of the topography and it is a requisite for the formation of ripples at near-normal incidence. It is shown also
that Fe is not homogeneously distributed on the surface, but there is a higher concentration at the crests of the ripples
than at the valleys. For the experimental setup used for this study, the Fe flux that reaches the surface is determined mainly
by the acceleration voltage (U
acc), while the ion energy (E
ion) and ion-beam incidence angle (α) control the concentration of Fe in the steady state. The adjustment of these operational parameters of the ion source enables
the fine-tuning of surface patterns. 相似文献
995.
A STUDY ON GRADIENT BLOW UP FOR VISCOSITY SOLUTIONS OF FULLY NONLINEAR, UNIFORMLY ELLIPTIC EQUATIONS
We investigate sharp conditions for boundary and interior gradient estimates of continuous viscosity solutions to fully nonlinear,uniformly elliptic equations under Dirichlet boundary conditions. When ... 相似文献
996.
We construct the generalized version of covariant Z3-graded differential calculus introduced by one of us (R.K.) and then extend it to the case of arbitrary ZN grading. Here our main purpose is to establish the recurrence formulae for the Nth power of covariant q-differential Dq=dq + A and to analyze more closely the particular case of q being an Nth primitive root of unity. The generalized notions of connection and curvature are introduced and several examples of realization are displayed for N=3 and 4. Finally we briefly discuss the idea of infinitesimal deformations of the parameter q in the complex plane. 相似文献
997.
998.
Inga K Teismann Olaf Steinstraeter Tobias Warnecke E Bernd Ringelstein Christo Pantev Rainer Dziewas 《BMC neuroscience》2009,10(1):76-7
Background
Dysphagia is a major complication of different diseases affecting both the central and peripheral nervous system. Pharyngeal sensory impairment is one of the main features of neurogenic dysphagia. Therefore an objective technique to examine the cortical processing of pharyngeal sensory input would be a helpful diagnostic tool in this context. We developed a simple paradigm to perform pneumatic stimulation to both sides of the pharyngeal wall. Whole-head MEG was employed to study changes in cortical activation during this pharyngeal stimulation in nine healthy subjects. Data were analyzed by means of synthetic aperture magnetometry (SAM) and the group analysis of individual SAM data was performed using a permutation test. 相似文献999.
We study the transport properties of ultrathin disordered nanowires in the neighborhood of the superconductor-metal quantum phase transition. To this end we combine numerical calculations with analytical strong-disorder renormalization group results. The quantum critical conductivity at zero temperature diverges logarithmically as a function of frequency. In the metallic phase, it obeys activated scaling associated with an infinite-randomness quantum critical point. We extend the scaling theory to higher dimensions and discuss implications for experiments. 相似文献
1000.
Fabrice Guittonneau Abdesselam Abdelouas Bernd Grambow Sandrine Huclier 《Ultrasonics sonochemistry》2010,17(2):391-398
Ultrasound treatment was used to study the decrease of the granulometry of graphite, due to the cavitation, which allows the erosion by separating grains. At a smaller scale, cavitation bubble implosion tears apart graphite sheets as shown by HRTEM, while HO and H radicals produced from water sonolysis, generate oxidative and reductive reactions on these sheet fragments. Such reactions form smaller species, e.g. dissolved organic matter. The methodology proposed is very sensitive to unambiguously identifying the in situ composition of organic compounds in water. The use of the atmospheric pressure chemical ionization (APCI) Fourier transform mass spectrometry (FTMS) technique minimizes the perturbation of the organic composition and does not require chemical treatment for analysis. The structural features observed in the narrow range (m/z < 300) were mainly aromatic compounds (phenol, benzene, toluene, xylene, benzenediazonium, etc.), C4–C6 alkenes and C2–C10 carboxylic acids. Synthesis of small compounds from graphite sonication has never been reported and will probably be helpful to understand the mechanisms involved in high energy radical reactions. 相似文献