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91.
Nitro musks in cosmetic products—determination by headspace solid-phase microextraction and gas chromatography with atomic-emission detection 总被引:1,自引:0,他引:1
Summary The combination of headspace solid-phase microextraction with atomic-emission detection enables highly selective and sensitive
determination of itro musk compounds in cosmetic products. Sample preparation is considerably simplified; there is no solvent
extraction step. Enrichment is influenced by the type and amount of cosmetic product investigated. The lowest amount giving
well detectable peaks is 1 mg musk compound per kg sample. Calibration curves obtained from spiked solutions of selected reference
cosmetics in water show very good linearity. Relative standard deviations of peak areas from repeated measurements are usually
<10%.
Presented at the 21st ISC held in Stuttgart, Germany, 15th–20th September, 1996 相似文献
92.
Erkki Mäkinen 《BIT Numerical Mathematics》1987,27(3):330-339
The splay tree is a self-adjusting binary search tree which has a good amortized performance. This paper studies some properties of top-down splay trees. Different ways to charge for the primitive operations of top-down splaying are discussed. We also give some empirical results concerning the behaviour of different top-down restructuring algorithms.This work was supported by the Academy of Finland. 相似文献
93.
P. Schwab A. Kochemasov R. Kullmer D. Bäuerle 《Applied Physics A: Materials Science & Processing》1992,54(2):166-169
Pulsed-laser deposition of YBa2Cu3O7 in N2O permits lowering of the substrate temperature with respect to deposition in O2 atmosphere. Additional photodissociation of N2O near the substrate surface deteriorates the superconducting properties of deposited films.On leave from: Institute of Applied Physics of the Academy of Sciences of the USSR, SU-603600 Nishni Nowgorod, USSR 相似文献
94.
In this paper we present photoionization cross sections of the Cu and Al dimers and tetramers. The local spin density method is applied to calculate the electronic structure and the ground state potential. The cross sections are calculated using the continuum multiple scattering method, and a basic analysis of the photoionization process is given within the independent particle picture. 相似文献
95.
The interaction of triethylgallium (TEG) with the Ga-stabilized GaAs(100) surface in the presence of In and Al has been investigated using AES (Auger electron spectroscopy), HREELS (high resolution electron energy loss spectroscopy) and TDS (thermal desorption spectroscopy) techniques. Al is shown to greatly increase the saturation surface coverage of TEG on the surface and to suppress the desorption of TEG and diethylgallium (DEG). Etching of the surface Al by TEG is observed, resulting in the formation of gas phase Al organic species. Alkyl migration from GA to Al centres occurs, and the presence of Al substantially enhances the irreversible deposition of C. In is found to enhance DEG desorption and to lower the temperature at which absorbed ethyl groups decompose to gas phase ethene. Computer modelling has been carried out to extract kinetic parameters from measured thermal desorption spectra. These parameters are then used to calculate expected partial growth rates of GaAs during the growth of GaxAl1−xAs and GaxIn1−xAs using TEG. The data provide a molecular level understanding of the GaAs pa rtial growth rate variations arising during the deposition of III–V ternary materials. 相似文献
96.
Christian R. Noe M. Knollmüller K. Dungler C. Miculka P. Gärtner 《Monatshefte für Chemie / Chemical Monthly》1991,122(8-9):705-718
Summary Acetals3 and4 of alkylthienylcarbinols1 were prepared using an enantiomerically pure lactol2. In the key step these compounds were desulfurized. After deprotection the target compounds7 andent-7 were obtained.
Herrn Prof. Dr. H. Oelschläger zum 70. Geburtstag gewidmet 相似文献
97.
In this work we study semifield planes of orderq
n(q=p
r
,p prime) with a collineation whose order is ap-primitive divisor ofq
n–1.Research supported in part by NSF Grant No. DMS-9107372Research supported in part by NSF grants RII-9014056, component IV of the EPSCoR of Puerto Rico grant and ARO grant for Cornell MSI. 相似文献
98.
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