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K. Wolke V. Harms H. W. Becker J. W. Hammer K. L. Kratz C. Rolfs U. Schröder H. P. Trautvetter M. Wiescher A. Wöhr 《Zeitschrift für Physik A Hadrons and Nuclei》1989,334(4):491-510
The22Ne(α, γ)26Mg and22Ne(α, n)25Mg reactions were investigated forE α(lab) from 0.71 to 2.25 MeV. Neon gas enriched to 99% in22Ne was recirculated in a differentially pumped gas target system of the extended type. Theγ-ray transitions were observed with Ge(Li) detectors and the neutrons with3He ionization chambers. A previously known resonance at ER(lab)=2.05 MeV was verified and 15 new resonances were found in the energy range covered, with the lowest at ER(lab)=0.83 MeV. Information on resonance energies, widths, strengths,γ-ray branching ratios, as well asJ π assignments, is reported. The energy range investigated corresponds to the important temperature range ofT 9 from 0.3 to 1.4 (109 K), for which the astrophysical rates were determined for both reactions. The results show that the ratios of the rates for22Ne(α, n)25Mg and22Ne(α, γ)26Mg are significantly smaller than the previously adopted values, e.g., by at least a factor of 60 nearT 9=0.65. Thus, the22Ne(α, n)25Mg reaction will likely play a smaller role as a neutron source fors-process nucleosynthesis, than has frequently been assumed. 相似文献
357.
H. Sixta H. Harms S. Dapia J.C. Parajo J. Puls B. Saake H.-P. Fink T. Röder 《Cellulose (London, England)》2004,11(1):73-83
New acidic organosolv pulping processes, such as Acetosolv, Formacell and Milox, promise to have superior potential in terms of purification selectivity and specific investment costs. Consequently, a thorough investigation of these new acidic pulping processes in comparison to state-of-the-art acidic magnesium sulfite technology was conducted. The impact of pulping and bleaching parameters on the physical and chemical characteristics was studied to compare process efficiency and selectivity for each type of pulp made from Eucalypt wood. In addition to a detailed analysis of the chemical composition and physical properties on a molecular and supramolecular level, the TCF-bleached dissolving pulps were tested for their applicability in viscose fiber production. The influence of pulp properties as determined by standard and advanced analytical methods on process performance and selected fiber properties is emphasized. 相似文献
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A new method and device for the ratiometric measurement of oxygen concentration are presented. They are based on the use of a dual-emission oxygen-sensitive dye. The method allows the exclusion of the influence of emission overlap. The detection of the dual-emission ratio is performed using a single long-pass emission filter. The device described is simpler than the widely used lifetime instruments and could easily be a stand-alone low-cost instrument. 相似文献
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[structure: see text] A urea-containing tetraphenoxy-substituted perylene bisimide has been synthesized, and its gelation ability has been studied. This functional dye forms fluorescent organogels in toluene and tetrachloromethane through self-assembly by hydrogen-bonding and pi-pi-stacking interactions. AFM and confocal laser scanning microscopy reveal the formation of fiberlike aggregates. 相似文献
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