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21.
From incoherent inelastic neutron scattering studies of solid C2Cl6 the in- and out-of-phase torsions about the C-C axis are assigned at 56 and 95 cm?1, respectively. Using a model for the potential barriers in the solid the torsional frequency in the gas has been calculated to be 76.7 cm?1 and the internal barrier to be 67.8 kJ mol?1. 相似文献
22.
G. Løvhøiden J.R. Lien J.C. Waddington J. Rekstad I. Espe C. Gaarde J.S. Larsen S. Van Der Werf 《Nuclear Physics A》1981,369(3):461-469
High-spin states have been located in 151Sm by means of the (α, 3He) reaction with 40 MeV α-particles. The scattered particles were momentum analyzed in a QMG/2 magnetic spectrometer and recorded in a position sensitive detector. Several high-spin states were observed in the energy range below 1.7 MeV excitation. The previously unknown strongly populated levels at 867 and 1480 keV can most likely be interpreted as states. Both the deduced nuclear structure factors and the energy location of these levels are in excellent agreement with a simple Coriolis coupling calculation. 相似文献
23.
Four separate reaction studies have been performed which show how the accepted nuclear level scheme for 158Tb must be modified. This nuclide is of current interest because of the recent suggestion that its electron-capture decay may yield a means of determining the neutrino mass. 相似文献
24.
DC Muddiman AP Null JC Hannis 《Rapid communications in mass spectrometry : RCM》1999,13(12):1201-1204
Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS) has been used to determine the mass of a double-stranded 500 base-pair (bp) polymerase chain reaction (PCR) product with an average theoretical mass of the blunt-ended (i.e. unadenylated) species of 308 859.35 Da. The PCR product was generated from the linearized bacteriophage Lambda genome which is a double-stranded template. Utilization of ethanol precipitation in tandem with a rapid microdialysis step to purify and desalt the PCR product was crucial to obtain a precise mass measurement. The PCR product (0.8 pmol/μL) was electrosprayed from a solution containing 75% acetonitrile, 25 mM piperidine, and 25 mM imidazole and was infused at a rate of 200 nL/min. The average molecular mass and the corresponding precision were determined using the charge-states ranging from 172 to 235 net negative charges. The experimental mass and corresponding precision (reported as the 95% confidence interval of the mean) was 309 406 +/- 27 Da (87 ppm). The mass accuracy was compromised due to the fact that the PCR generates multiple products when using Taq polymerase due to the non-template directed 3'-adenylation. This results in a mixture of three PCR products with nearly identical mass (i.e. blunt-ended, mono-adenylated and di-adenylated) with unknown relative abundances that were not resolved in the spectrum. Thus, the experimental mass will be a weighted average of the three species which, under our experimental conditions, reflects a nearly equal concentration of the mono- and di-adenylated species. This report demonstrates that precise mass measurements of PCR products up to 309 kDa (500 bp) can be routinely obtained by ESI-FTICR requiring low femtomole amounts. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
25.
Marchesan S Easton CD Kushkaki F Waddington L Hartley PG 《Chemical communications (Cambridge, England)》2012,48(16):2195-2197
Change of chirality of the first N-terminal amino acid of tripeptides VFF and FFV from l to d results in self-assembled hydrogels at physiological pH from non-assembling l-analogues. Interestingly, changing the chirality of F yields very different nanostructures; nanotapes are observed for (D)VFF, twisted fibers for (D)FFV. 相似文献
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Simon Waddington 《Communications in Mathematical Physics》1996,176(2):273-305
We derive various asymptotic formulae for the numbers of closed orbits in the Lorenz and Horseshoe templates with given knot invariants, (for example braid index and genus). We indicate how these estimates can be applied to more complicated flows by giving a bound for the genus of knotted periodic orbits in the figure of eight template. 相似文献
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