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191.
Klaus Jansen Lorant Porkolab 《Journal of Algorithms in Cognition, Informatics and Logic》2002,45(2):592
We study preemptive and non-preemptive versions of the general multiprocessor job shop scheduling problem: Given a set of n tasks each consisting of at most μ ordered operations that can be processed on different (possibly all) subsets of m machines with different processing times, compute a schedule (preemptive or non-preemptive, depending on the model) with minimum makespan where operations belonging to the same task have to be scheduled according to the specified order. We propose algorithms for both preemptive and non-preemptive variants of this problem that compute approximate solutions of any positive ε accuracy and run in O(n) time for any fixed values of m, μ, and ε. These results include (as special cases) many recent developments on polynomial time approximation schemes for scheduling jobs on unrelated machines, multiprocessor tasks, and classical open, flow and job shops. 相似文献
192.
Studies on Sodium Trifluormethanesulfonate – Crystal Structure and Phase Transition of Sodium Trifluormethanesulfonate Monohydrate and Sodium Ion Conductivity of Anhydrous Sodium Trifluormethanesulfonate According to the results of temperature dependent powder diffractometry (Guinier-Simon-technique) sodium trifluormethanesulfonate monohydrate is dimorphous. The phase transition occurs at ?35°C. The room-temperature modification crystallizes monoclinic in space group P21/c with the lattice parameters a = 941.6(5) pm, b = 654.3(2) pm, c = 1062.4(5) pm and β = 107.73(2)°. The crystal structure consists of double layers of trifluormethanesulfonate anions, the lipophilic CF3-groups pointing at each other. Sodium is coordinated by four oxygen atoms from four different anions and by two molecules of crystal water. The resulting polyhedron may be addressed as a distorted octahedron. The low-temperature modification crystallizes orthorhombic in space group Pnma with the lattice parameters a = 645.31(9) pm, b = 538.03(9) pm, c = 1745.3(3) pm. The loss of crystal water occurs at 136°C. Anhydrous sodium trifluormethanesulfonate shows a phase transition at 252°C. The high-temperature modification is a good sodium ionic conductor (σ = 4.1 · 10?1 Ω?1 cm?1 at 250°C). 相似文献
193.
F. G. J. Poelma J. J. Tukker H. W. Hilbers A. C. A. Jansen 《Journal of inclusion phenomena and macrocyclic chemistry》1989,7(4):423-430
The inclusion of dantrolene sodium, a muscle relaxant with poor water-solubility, in-,- and-cyclodextrins was determined. Subsequently, the influence of the cyclodextrins on the absorption of the drug from aqueous solutions was investigated in a chronically isolated internal loop in the small intestine of the rat.A good correlation was found between the inclusion of dantrolene in the various cyclodextrins and the decrease in the absorption rate resulting from a reduction of the thermodynamically active dantrolene according to the phase-separation model. It was concluded that the cyclodextrins do not have a significant influence on the passage of dantrolene across the absorption barrier. Furthermore, experimental evidence was collected to support the fact that-cyclodextrin was absorbed to a limited, if not negligible, extent in the small intestine of the rat. 相似文献
194.
195.
B J Koopman G Jansen B G Wolthers J R Beukhof J G Go G K van der Hem 《Journal of chromatography. A》1985,337(2):259-266
The determination of sulphate in plasma is described, making use of reversed-phase high-performance liquid chromatography with ultraviolet detection. The concentration of inorganic sulphate determined in plasma of twenty healthy volunteers was 0.307 +/- 0.092 mmol/l (mean +/- S.D.). In one stable chronic dialysis patient the kinetics of plasma sulphate removal were monitored during and after one single pass dialysis. In addition, plasma sulphate concentrations were determined in three stable chronic dialysis patients during a consecutive scheme of two single pass dialyses, five Redy dialyses and three single pass dialyses. As expected, plasma sulphate accumulates in plasma to a high steady-state level under Redy dialysis, whereas during single pass dialysis sulphate is efficiently removed. 相似文献
196.
197.
J. J. Yang L. Lee M. Jansen M. Sergant S. S. Ou J. Wilcox 《Fiber and Integrated Optics》1988,7(3):217-228
Surface emitting lasers are of interest for various applications such as monolithic two-dimensional arrays and optical interconnects for integrated optics. Moreover, surface emitting lasers offer the advantage of wafer processing and testing. Several approaches for achieving surface emission are described. In addition, TRW s fabrication of a large monolithic two dimensional array of GaAs/AlGaAs surface emitting lasers which contains a total of 100 lasers is reported. 相似文献
198.
Johanna Sepp 《Fresenius' Journal of Analytical Chemistry》1960,174(4):289
Ohne Zusammenfassung 相似文献
199.
B.J. Jansen Tj. Hollander C.Th.J. Alkemade 《Journal of Quantitative Spectroscopy & Radiative Transfer》1977,17(5):663-671
Using a pressure-scanned Fabry-Pérot interferometer, we measured spectral profiles of the self-absorbed Sr resonance line at 4607.33Åemitted in a pre-mixed, laminar, shielded air-C2H2 flame at 1 atm for various Sr-solution concentrations. The dependence of the full width at one-half maximum (FWHM) on Sr atomic density in the flame was found to agree with a calculation based on the Voigt expression and Beer's law. It appears that one can derive the FWHM under optically thin conditions (i.e. at vanishing Sr atomic density) by linear extrapolation from measurements made at higher concentrations where the signal-to-noise ratio is good, but broadening due to self-absorption plays a role. 相似文献
200.
Summary A suitable and simple method for the quantitative determination of moniliformin in vegetable foods and feeds is described. The mycotoxin was extracted by Soxhlet extraction with methanol from mouldy maize, rice, rye, oats, wheat and barley samples. Moniliformin was determined by thin-layer chromatography (TLC) using N-methylbenzthiazolon-2-hydrazone (MBTH) as a new derivatization reagent for this mycotoxin. The moniliformin derivative was assayed at 518 nm. Quantification could be performed after calibration. A linear relationship between mycotoxin amount and peak area was found from 100 to 400 ng/spot. The detection limit is 75 ng/spot.
Quantitative Bestimmung von Moniliformin in pflanzlichen Nahrungs- und Futtermitteln
Zusammenfassung Eine geeignete Analysenmethode zur Bestimmung von Moniliformin in Nahrungs- und Futtermitteln wird beschrieben. Das Toxin wurde aus verschimmeltem Mais, Reis, Roggen, Hafer, Weizen und Gerste extrahiert. Der Extrakt wurde anschließend dünnschicht-chromatographisch getrennt und Moniliformin mit N-Methylbenzthiazolon-2-hydrazon (MBTH), einem für den DC-Nachweis neuen Reagens, nachgewiesen. Das gebildete Moniliforminderivat konnte bei 518 nm in Remission bestimmt werden. Mit Hilfe einer Eichkurve wurden die erhaltenen Daten quantitativ ausgewertet. Ein linearer Zusammenhang zwischen Substanzmenge und Peakfläche besteht für den Bereich von 100–400 ng pro Fleck. Die Nachweisgrenze beträgt nach dieser Methode 75 ng/Fleck.相似文献