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H. Stange K. Petermann G. Huber E. W. Duczynski 《Applied physics. B, Lasers and optics》1989,49(3):269-273
We report on room-temperature cw laser action of Er3+: Yttrium-aluminum-garnet (YAG) and Er3+: Yttrium-gallium-garnet (YGG) crystals at 1.64 m. The laser operates from the metastable4
I
13/2 manifold into an upper Stark level of the4
I
15/2 ground-state manifold of Er3+. Due to reabsorption losses, the Er3+ concentration of the laser crystals must be low. Laser pumping at a wavelength of 647.1 nm yields lowest thresholds around 30 mW and slope efficiencies up to 12.7% for Er:YAG. Laser operation in Er:YGG is achieved with higher thresholds of about 200 mW and smaller slope efficiencies of 0.9%. The effective emission cross section in YAG is estimated to be e5×10–21 cm2.Dedicated to Prof. Dr. Herbert Welling on the occasion of his 60th birthday 相似文献
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F. Kanne und K. Stange 《Fresenius' Journal of Analytical Chemistry》1962,189(3):261-265
Zusammenfassung Es wird über ein gaschromatographisches Verfahren zur Bestimmung von Spuren Phenol, insbesondere im Bisphenol A (2,2-Bis-[4-hydroxyphenol]-propan) berichtet. Die beschriebene Methode erlaubt die Phenolbestimmung im Bisphenol A in wesentlich kürzerer Zeit als die bisher üblichen Methoden (z.B. Wasserdampfdestillation und jodometrische Endbestimmnung). Das gaschromatographische Verfahren benötigt für eine komplette Bestimmung 7–8 min. Ausserdem arbeitet das beschriebene Verfahren im ppm-Bereich mit größerer Genauigkeit. So wurde im Bereich von 75 ppm Phenol im Bisphenol A ein Wiederholstreubereich von ±6% rel. gefunden. In diesem Konzentrationsbereich sind die Abweichungen bei der bisher üblichen Methode zum Teil über 100% vom Sollwert. 相似文献
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The synthesis of the octapeptide derivative Z-Phe-Val-Asn-Gln-His(Trt)-Leu-Cys(SEt)-Gly-OH with the terminal sequence 1-8 of the insulin B chain using the subunits Z-Phe-Val-OH, Boc-Asn-Gln-His(Trt)-OMe and Boc-Leu-Cys(SEt)-Gly-OH is reported. 相似文献
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Stange CF Spott O Apelt B Russow RW 《Isotopes in environmental and health studies》2007,43(3):227-236
On the basis of the principle of reaction continuous-flow quadrupole mass spectrometry, an automated sample preparation unit for inorganic nitrogen (SPIN) species was developed and coupled to a quadrupole Mass Spectrometer (MAS). The SPINMAS technique was designed for an automated, sensitive, and rapid determination of 15N abundance and concentration of a wide variety of N-species involved in nitrogen cycling (e.g. NH4+, NO3-, NH2OH etc.). In this paper, the SPINMAS technique is evaluated with regard to the determination of 15N abundance and concentration of the most fundamental inorganic nitrogen compounds in ecosystems such as NH4+, NO2-, and NO3-. The presented paper describes the newly developed system in detail and demonstrates the general applicability of the system. For a precise determination of 15N abundance and concentration, a minimum total N-amount of 10 microg NH4+ - N, 0.03 microg NO2- - N, or 0.3 microg NO3- - N has to be supplied. Currently, the SPINMAS technique represents the most rapid and only fully automated all-round method for a simultaneous determination of 15N abundance and total N-amount of NH4+, NO2-, or NO3- in aqueous samples. 相似文献
10.
Ion Pairing in Protic Ionic Liquids Probed by Far‐Infrared Spectroscopy: Effects of Solvent Polarity and Temperature
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Dr. Koichi Fumino Verlaine Fossog Peter Stange Kai Wittler Wigbert Polet Prof. Dr. Rolf Hempelmann Prof. Dr. Ralf Ludwig 《Chemphyschem》2014,15(12):2604-2609
The cation–anion and cation–solvent interactions in solutions of the protic ionic liquid (PIL) [Et3NH][I] dissolved in solvents of different polarities are studied by means of far infrared vibrational (FIR) spectroscopy and density functional theory (DFT) calculations. The dissociation of contact ion pairs (CIPs) and the resulting formation of solvent‐separated ion pairs (SIPs) can be observed and analyzed as a function of solvent concentration, solvent polarity, and temperature. In apolar environments, the CIPs dominate for all solvent concentrations and temperatures. At high concentrations of polar solvents, SIPs are favored over CIPs. For these PIL/solvent mixtures, CIPs are reformed by increasing the temperature due to the reduced polarity of the solvent. Overall, this approach provides equilibrium constants, free energies, enthalpies, and entropies for ion‐pair formation in trialkylammonium‐containing PILs. These results have important implications for the understanding of solvation chemistry and the reactivity of ionic liquids. 相似文献