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41.
An analytical procedure for the simultaneous determination in human serum of 43 common drugs of abuse and their metabolites
belonging to the different chemical and toxicological classes of amphetamines, benzodiazepines, dibenzazepines, cocaine, lysergic
acid diethylamide, opioids, phencyclidine, tricyclic antidepressants, and zolpidem, using 33 deuterated standards, is presented.
The sample treatment was developed to be a very simple protein precipitation and filtration. All analyses were performed with
a high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry in positive ionization mode. All
analytes were calibrated up to 550 μg/L. The limit of detection ranged from 0.6 ng/mL (EDDP) to 13.7 ng/mL (flunitrazepam).
The method has been validated according to the guidelines of the Gesellschaft für Toxikologische und Forensische Chemie, using three multiple reaction mode (MRM) transitions and retention time for positive compound identification, instead of
two MRMs, in anticipation of the new guidelines for January 2011. 相似文献
42.
Christian Mittelstedt Henrike Erdmann Kai-Uwe Schröder 《Archive of Applied Mechanics (Ingenieur Archiv)》2011,81(10):1409-1426
In this paper, the postbuckling behavior of rectangular orthotropic laminated composite plates with initial imperfections
under inplane shear load is investigated in a closed-form analytical manner. The plates under consideration are assumed to
be infinitely long in the longitudinal direction. At the longitudinal edges, two different sets of boundary conditions are
considered, specifically 1) simply supported edges and 2) fully clamped edges. Using Timoshenko-type shape functions for both
the initial bifurcational buckling analysis and the subsequent Marguerre-type postbuckling studies, closed-form analytical
solutions for the buckling loads and for the postbuckling state variables are derived. A comparison with geometrically non-linear
finite element computations shows that the derived analysis approaches are suitable for postbuckling studies in load ranges
not too far beyond bifurcational buckling as they are currently relevant for e.g., composite airframe structural analysis
and design. Due to their strictly closed-form analytical nature, the presented analysis methods can be used conveniently in
engineering practice for all application purposes where computational time is a crucial factor, especially for preliminary
analysis and design or optimization procedures. 相似文献
43.
In this paper we give an approximate probability distribution for the maximum order complexity of a random binary sequence. This enables the development of statistical tests based on maximum order complexity for the testing of a binary sequence generator. These tests are analogous to those based on linear complexity. 相似文献
44.
45.
H. Erdmann H. Mennicke G. Romijn A. Fernau L. Spiegel Adrian und Ed. Schaer 《Fresenius' Journal of Analytical Chemistry》1902,41(11):703-706
Ohne Zusammenfassung 相似文献
46.
47.
48.
K. Erdmann W. Czerwinski B. C. Gerstein M. Pruski 《Journal of Polymer Science.Polymer Physics》1994,32(12):1961-1968
Transient techniques in NMR of 1H and 13C were used to study the chemical and physical structures of solid poly(p-phenylene) (PPP), poly(2,6-dimethyl-p-phenylene oxide) (PDMPO), poly(p-phenylene sulfide) (PPS), poly(p-biphenylene sulfide) (PPBS), poly(p-phenylene selenide) (PPSe), poly(p-biphenylene selenide) (PPBSe), poly(2,5-thienylene) (PT), poly(3-methyl-2,5-thienylene) (PMT), and poly(p-phenylene-co-2,5-thienlyene) (PPPT) of different monomer ratios. 13C NMR confirmed the expected chemical structure for homopolymers, and indicated a random distribution of monomer units in PPPT. Relative fractions of crystalline and interfacial regions were determined by measurements of 1H magnetic relaxation, 13C CP/MAS NMR, and XRD. © 1994 John Wiley & Sons, Inc. 相似文献
49.
50.
Karin Erdmann 《Mathematische Annalen》1988,281(4):545-560