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31.
A short,highly efficient synthesis of coenzyme Q(10) 总被引:5,自引:0,他引:5
Lipshutz BH Mollard P Pfeiffer SS Chrisman W 《Journal of the American Chemical Society》2002,124(48):14282-14283
The most efficient synthesis reported to date of ubiquinone (CoQ10) is described. A sequence consisting of six operations is involved which leads to crystalline material in an overall yield of >64%. 相似文献
32.
B. Endeward M. Plato S. Will E. Vogel A. Szyczewski K. Möbius 《Applied magnetic resonance》1998,14(1):69-80
The “Contracted Porphyrins” corrole and the recently synthesized isocorrole (as octaethyl derivatives) represent novel porphyrinoid macrocycles of biochemical interest. The radical cations of the free-bases of both corrole and its isomer are studied by EPR, ENDOR, and TRIPLE resonance in liquid solution to measure isotropic hyperfine couplings including signs. They yield detailed information of the electronic structure of the radical cations. The experimental findings are compared with results of all-valence-electrons self-consistent field molecular orbital calculations (RHF-INDO/SP). The comparison shows that the free-bases of corrole and isocorrole undergo protonation when oxidized to cation radicals in CH2Cl2 solution. Excellent agreement of the measured and calculated spin density distributions is achieved for the protonated dication radicals, which exhibit the C2 symmetry observed for the hyperfine structure. The analysis of the hyperfine data discriminates against NH tautomerism as the sole source for an effective C2 symmetry of the macrocycle. 相似文献
33.
34.
L. Funke F. Dnau J. Dring P. Kemnitz E. Will G. Winter 《Physics letters. [Part B]》1983,120(4-6):301-304
A shape transition from a probably asymmetric shape at low excitation to a more axial-symmetric shape above 21/2+ has been found in 81Kr. This shape change and the drastic increase of the M1 transition probabilities above spin 21/2 are attributed to the alignment of two g9/2 protons. 相似文献
35.
36.
We determine the poles and residues of the resolvent kernel of the Laplacian on a Damek-Ricci space We show that all poles are simple and the residues define convolution operators of finite rank. This generalizes a result of Guillopé-Zworski for the real hyperbolic -space. If corresponds to a symmetric space of negative curvature , the image of each residue is a -module with a specific highest weight. We compute the dimension by the Weyl dimension formula.
37.
Gailitis A Lielausis O Dement'ev S Platacis E Cifersons A Gerbeth G Gundrum T Stefani F Christen M Hanel H Will G 《Physical review letters》2000,84(19):4365-4368
In a closed volume of molten sodium an intense single-vortex-like helical flow has been produced by an outside powered propeller. At a flow rate of 0.67 m(3)/s a slowly growing magnetic field eigenmode was detected. For a slightly lower flow, additional measurements showed a slow decay of this mode. The measured results correspond satisfactorily with numerical predictions for the growth rates and frequencies. 相似文献
38.
H.A. Michelsen F. Liu B.F. Kock H. Bladh A. Boiarciuc M. Charwath T. Dreier R. Hadef M. Hofmann J. Reimann S. Will P.-E. Bengtsson H. Bockhorn F. Foucher K.-P. Geigle C. Mounaïm-Rousselle C. Schulz R. Stirn B. Tribalet R. Suntz 《Applied physics. B, Lasers and optics》2007,87(3):503-521
We have performed a comparison of ten models that predict the temporal behavior of laser-induced incandescence (LII) of soot.
In this paper we present a summary of the models and comparisons of calculated temperatures, diameters, signals, and energy-balance
terms. The models were run assuming laser heating at 532 nm at fluences of 0.05 and 0.70 J/cm2 with a laser temporal profile provided. Calculations were performed for a single primary particle with a diameter of 30 nm
at an ambient temperature of 1800 K and a pressure of 1 bar. Preliminary calculations were performed with a fully constrained
model. The comparison of unconstrained models demonstrates a wide spread in calculated LII signals. Many of the differences
can be attributed to the values of a few important parameters, such as the refractive-index function E(m) and thermal and
mass accommodation coefficients. Constraining these parameters brings most of the models into much better agreement with each
other, particularly for the low-fluence case. Agreement among models is not as good for the high-fluence case, even when selected
parameters are constrained. The reason for greater variability in model results at high fluence appears to be related to solution
approaches to mass and heat loss by sublimation.
PACS 65.80.+n; 78.20.Nv; 42.62.-b; 44.05.+e 相似文献
39.