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91.
92.
Pure iron foils have been implanted with Ti and with Ti plus C and characterized by conversion electron Mössbauer spectroscopy (CEMS) and Auger electron spectroscopy (AES). Both paramagnetic and magnetic phases are observed and attributed to amorphous Fe?Ti?C alloys of differing Ti and C contents. Estimates of the thicknesses of the amorphous layers based on the CEMS data are in good agreement with the AES concentration depth profiles. 相似文献
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Jordan D McIlvain T Alarcon R Beck R Bertozzi W Bhushan V Boeglin W Chen JP Dale D Dodson G Dolfini S Dow K Dzengeleski J Epstein MB Farkhondeh M Gilad S Görgen J Holtrop M Joo K Kelsey J Kim W Laszewski R Lourie R Mandeville J Margaziotis D Martinez D Miskimen R Papanicolas CN Penn S Sapp W Sarty AJ Tieger D Tschalaer C Turchinetz W Warren G Weinstein L Williamson S 《Physical review letters》1996,76(10):1579-1582
97.
State-selective detection of molecular hydrogen by VUV laser-induced fluorescence has been achieved at excitation wavelengths greater than the lithium fluoride cut-off, using xenon as the non-linear medium. With this approach sensitivities of ≈109 per cm3 per quantum state have been achieved under cell conditions. This method provides a simple approach to monitoring the vibrational state distribution of hydrogen and its isotopes. 相似文献
98.
An efficient, general procedure for highly chemoselective reductive mono-alkylation of ammonia with ketones is reported. Treatment of ketones with ammonia in ethanol and titanium(IV) isopropoxide, followed by in situ sodium borohydride reduction, and a straightforward workup afforded primary amines in good to excellent yields. Reductive alkylation of ammonia with aldehydes, on the other hand, afforded the corresponding symmetrical secondary amines selectively. 相似文献
99.
Both the techniques mentioned provide molecular weight and structural information, but laser microprobe mass spectrometry (LMMS) also provides greater control over the degree of fragmentation and enhanced sensitivity. In addition, LMMS allows microprobe analysis (i.e., spatial resolution of a few μm2) as well as providing quantitative measurements. The less energetic nature of fast-atom-bombardment mass spectrometry (FAB-MS) makes it more suitable for the analysis of highly labile polar compounds and high-mass biopolymers. 相似文献
100.
L. B. Beasley J. L. Brenner P. Erdős M. Szalay A. G. Williamson 《Periodica Mathematica Hungarica》1987,18(4):259-269
Considering the conjugacy classes of the alternating group of degreen, those classes that contain a pair of generators are in the majority. In fact, the proportion of such classes is 1 –(n), and(n) 0 asn . 相似文献