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161.
A. R. N. Wilson L. J. M. van de Ven J. W. de Haan 《Magnetic resonance in chemistry : MRC》1974,6(11):601-602
Carbon-13 NMR chemical shifts have been measured in a number of binary mixtures of normal alkanes. Intrinsic solvent shifts are deduced from the shifts and the relevance of some small substituent effects in alkanes is discussed. A comparison is made between solvent effects and thermally induced chemical shift differences in alkanes. 相似文献
162.
The 13C NMR α-substituent effects within the series methane to neopentane and ethene to isobutene have been calculated using Hartree—Fock perturbation theory with MINDO/3. The sign and order of magnitude of the calculated α-effects are in agreement with new experimental values, including effects of multiple substitution. 相似文献
163.
For the translocation of a polymer through a nanopore, a quasistatic assumption for the dynamics yields a tractable form for the entropic barrier. Although this is a much simplified model, interesting features such as robust scaling emerge from its application. To explore these details, we present a method of mapping the translocation process as an incremental mean first passage problem. In this approach, the quantity of interest is the average first time t(0) at which the polymer achieves a displacement of Δs in the translocation coordinate s. Constructing scenarios with different initial conditions and boundary conditions, analytic and exact numerical approaches are used to resolve the dynamics of translocation in detail and generate new insight into the nature of the entropic barrier. 相似文献
164.
Haan C Rolvering C Raulf F Kapp M Drückes P Thoma G Behrmann I Zerwes HG 《Chemistry & biology》2011,18(3):314-323
Genetic deficiency of Jak3 leads to abrogation of signal transduction through the common gamma chain (γc) and thus to immunodeficiency suggesting that specific inhibition of Jak3 kinase may result in immunosuppression. Jak1 cooperates with Jak3 in signaling through γc-containing receptors. Unexpectedly, a Jak3-selective inhibitor was less efficient in abolishing STAT5 phosphorylation than pan-Jak inhibitors. We therefore explored the roles of Jak1 and Jak3 kinase functionality in signaling using a reconstituted system. The presence of kinase-inactive Jak1 but not kinase-inactive Jak3 resulted in complete abolishment of STAT5 phosphorylation. Specific inhibition of the "analog-sensitive" mutant AS-Jak1 but not AS-Jak3 by the ATP-competitive analog 1NM-PP1 abrogated IL-2 signaling, corroborating the data with the selective Jak3 inhibitor. Jak1 thus plays a dominant role over Jak3 and these data challenge the notion that selective ATP-competitive Jak3 kinase inhibitors will be effective. 相似文献
165.
Hans de Haan 《Computational & Mathematical Organization Theory》2008,14(4):302-319
In this article a mathematical framework is introduced and explored for the study of processes in societal transitions. A
transition is conceptualised as a fundamental shift in the functioning of a societal system. The framework views functioning
as a real-valued field defined upon a real variable. The initial status quo prior to a transition is captured in a field called
the regime and the alternative that possibly takes over is represented in a field called a niche. Think for example of a transition
in an energy supply system, where the regime could be centrally produced, fossil fuel based energy supply and a niche decentralised
renewable energy production. The article then proceeds to translate theoretical notions on the interactions and dynamics of
regimes and niches from transition literature into the language of this framework. This is subsequently elaborated in some
simple models and studied analytically or by means of computer simulation.
相似文献
Hans de HaanEmail: URL: http://www.eur.nl/fsw/staff/homepages/dehaan/ |
166.
Ensembles of 400,000 two-electron trajectories in three space dimensions are used with Newtonian equations of motion to track atomic double ionization under very strong laser fields. We report a variable time lag between e-e collision and double ionization, and find that the time lag plays a key role in the emergence directions of the electrons. These are precursors to production of electron momentum distributions showing substantial new agreement with experimental data. 相似文献
167.
Döppner T Thomas CA Divol L Dewald EL Celliers PM Bradley DK Callahan DA Dixit SN Harte JA Glenn SM Haan SW Izumi N Kyrala GA LaCaille G Kline JK Kruer WL Ma T MacKinnon AJ McNaney JM Meezan NB Robey HF Salmonson JD Suter LJ Zimmerman GB Edwards MJ MacGowan BJ Kilkenny JD Lindl JD Van Wonterghem BM Atherton LJ Moses EI Glenzer SH Landen OL 《Physical review letters》2012,108(13):135006
We have imaged hard x-ray (>100 keV) bremsstrahlung emission from energetic electrons slowing in a plastic ablator shell during indirectly driven implosions at the National Ignition Facility. We measure 570 J in electrons with E>100 keV impinging on the fusion capsule under ignition drive conditions. This translates into an acceptable increase in the adiabat α, defined as the ratio of total deuterium-tritium fuel pressure to Fermi pressure, of 3.5%. The hard x-ray observables are consistent with detailed radiative-hydrodynamics simulations, including the sourcing and transport of these high energy electrons. 相似文献
168.
In environmental applications of extreme value statistics, the underlying stochastic process is often modeled either as a max-stable process in continuous time/space or as a process in the domain of attraction of such a max-stable process. In practice, however, the processes are typically only observed at discrete points and one has to resort to interpolation to fill in the gaps. We discuss the influence of such an interpolation on estimators of marginal parameters as well as estimators of the exponent measure. In particular, natural conditions on the fineness of the observational scheme are developed which ensure that asymptotically the interpolated estimators behave in the same way as the estimators which use fully observed continuous processes. 相似文献
169.
Oswald Haan 《Fortschritte der Physik》1979,27(1):35-74
This review describes a field in the S-matrix theory of elastic stattering. Analyticity and elastic unitarity in the crossed t-channel are shown in a rigorous manner to yield constraints on s-channel quantities. Strong restrictions on s-channel partial wave with angular momenta l ⩾√s/2(b0 + λ In s) follow from realistic assumptions on the amplitude in the unphysical domain (Mandelstam analyticity and Regge behaviour). The possibility of phenomenological application of these results is discussed. 相似文献