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31.
Ata?Allah?Taleizadeh Solaleh?Sadat?Kalantari Leopoldo?Eduardo?Cárdenas-BarrónEmail author 《TOP》2016,24(1):143-155
This paper deals with an economic production quantity (EPQ) inventory model with reworkable defective items when a given multi-shipment policy is used. In this work, it is assumed that in each cycle, the rework process of all defective items starts when the regular production process finishes. After the rework process, a portion of reworked items fails. This portion becomes scrap and only the perfect finished items can be delivered to customers at the end of rework process. A profit function is derived to model the inventory problem and it is shown that the profit function is concave. Due to the complexity of the optimization problem, an algorithm is developed to determine the optimal values of manufacturing lot size and price such that the long-run average profit function is maximized. Furthermore, two special cases are identified and explained. Finally, a numerical example is given to illustrate the applicability of the proposed inventory model. 相似文献
32.
Parametric Study of Nonplanar Dust Acoustic Solitons in Two‐Dimensional Superthermal Dusty Plasmas
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The nonlinear properties of two dimensional low‐frequency electrostatic excitations of charged dust particles (or defects) are studied in a collisionless, unmagnetized dusty plasma. A fully ionized three‐component model plasma consisting of kappa distributed electrons, Maxwellian ions, and negatively charged massive dust grains is considered. In this regard, the well known reductive perturbation technique is used to the hydrodynamical equations and the Poisson equation, obtaining the cylindrical Kadomtsev–Petviashvili (CKP) equation. A parametric investigation indicates that the structural characteristics of these nonlinear excitations (width, amplitude) are significantly affected by the plasma nonthermality as well as by the relevant plasma parameters, such as dust concentration and dust temperature. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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M. Ramm M. Ata T. Gross W. Unger 《Applied Physics A: Materials Science & Processing》2000,70(4):387-390
We report core-level and valence-band X-ray photoelectron spectroscopy (XPS) and carbon [
]K near-edge X-ray-absorptionfine structure spectroscopy (NEXAFS) results of plasma-polymerized C60. In comparison with evaporated C60 the C 1s peak is broader and asymmetric for the C60 polymer and its shake-up satellites diminished. Furthermore, the features of the valence-band as well as the features of
the π* antibonding orbitals of the C60 polymer are broader and reduced in intensity. Changes in the electronic structure are attributed to the polymerization of
C60, the post-plasma functionalization of the surface by oxygen after exposure to atmosphere, and the occurrence of amorphous
carbon.
Received: 28 May 1999 / Accepted: 31 August 1999 / Published online: 8 March 2000 相似文献
35.
We studied the deposition of C60 polymer films under different Ar plasma conditions. The films were deposited at a pressure range between 1.3 and 40 Pa, and the input power was varied from 10 to 70 W. The films were investigated by Raman spectroscopy to confirm the C-C valence states of the polymeric phases. C60 polymers were formed under various experimental conditions. However, the depositions resulted in non-uniform films consisting of unpolymerized C60, dimers, linear chains and polymeric planes. Amorphous carbon was found in the films deposited at 13 and 20 Pa (50 W input power) and 13 Pa (70 W). 相似文献
36.
A gas chromatography-mass spectrometry (GC-MS) method has been proposed for the determination of aliphatic and aromatic amines in a variety of environmental samples including wastewater, river water, sea water and sediment samples. The method includes ion-pair extraction with bis-2-ethylhexylphosphate (BEHPA), derivatisation of compounds with isobutyl chloroformate (IBCF) and their GC-MS analysis. Aliphatic and aromatic amines were isolated from aqueous samples using BEHPA as ion-pair reagent and derivatised with IBCF for their chromatographic analysis. Solid-liquid extraction of aliphatic and aromatic amines in sediment samples were performed in Soxhlet apparatus with acidic MeOH and ion-pair extraction with BEHPA were carried out for the isolation of amines followed by derivatisation with IBCF. Aliphatic and aromatic amines were then analysed with GC-MS in both electron impact (EI) and positive and negative ion chemical ionisation (PNICI) mode as their isobutyloxycarbonyl (isoBOC) derivatives. The obtained recoveries ranged from 81.0 to 98.0% and the precision of this method, as indicated by the relative standard deviations (RSDs) was within the range of 0.5 and 4.3%. The detection limits obtained from calculations by using GC-MS results based on S/N = 3 were within the range from 0.07 to 0.50 ng/l. 相似文献
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A process which has just one jump, and whose time parameter is the positive quadrant [0, ∞] × [0, ∞], is considered. Following Merzbach, related stopping lines are introduced, and the filtration {t1,t23} considered in this paper is such that, modulo completion, the σ-field t1,t23 is the Borel field on the region , together with the atom which is the complement in Ω = [0, ∞]2 of Lt1,t2. Optional and predictable projections of related processes are defined, together with their dual projections, and an integral representation for martingales is obtained. 相似文献
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A class of open processing networks operating under a maximum pressure policy is considered in the heavy traffic regime. We prove that the diffusion-scaled workload process for a network with several bottleneck resources converges to a semimartingale reflecting Brownian motion (SRBM) living in a polyhedral cone. We also establish a state space collapse result that the queue length process can be lifted from the lower-dimensional workload process. 相似文献