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排序方式: 共有334条查询结果,搜索用时 31 毫秒
241.
Abdiaziz A. Farah Raluca Voicu Farid Bensebaa Karim Faid 《Applied Surface Science》2006,252(14):5158-5167
A novel alkylthioacetyl-capped hydroxyethyl methacrylate monomer and its corresponding homopolymer have been synthesized and characterized. Direct chemisorption of these moieties have been carried out on gold-coated substrate and found to form a strong surface bonding. The surface coverage and the properties of the resultant self-assembled layers have been investigated by multiple surface characterization techniques (i.e. ellipsometry, GA-FTIR, XPS, AFM, and contact angle measurements). These analyses have all confirmed the occurrence of complete chemisorption reactions with typical n-alkanethiol self-assembled characteristics. 相似文献
242.
Given a schedule of flights to be flown, the aircraft fleeting and routing problem (AFRP) consists of determining a minimum-cost route assignment for each aircraft so as to cover each flight by exactly one aircraft while satisfying maintenance requirements and other activity constraints. We investigate network flow-based heuristic approaches for this problem. Computational experiments conducted on real-data given by TunisAir show that the proposed heuristic consistently yields very near-optimal solutions while requiring modest CPU effort. 相似文献
243.
Öykü Naz Attila Agostinho Agra Kerem Akartunalı Ashwin Arulselvan 《European Journal of Operational Research》2021,288(2):496-510
In this paper, we consider a lot-sizing problem with the remanufacturing option under parameter uncertainties imposed on demands and returns. Remanufacturing has recently been a fast growing area of interest for many researchers due to increasing awareness on reducing waste in production environments, and in particular studies involving remanufacturing and parameter uncertainties simultaneously are very scarce in the literature. We first present a min-max decomposition approach for this problem, where decision maker’s problem and adversarial problem are treated iteratively. Then, we propose two novel extended reformulations for the decision maker’s problem, addressing some of the computational challenges. An original aspect of the reformulations is that they are applied only to the latest scenario added to the decision maker’s problem. Then, we present an extensive computational analysis, which provides a detailed comparison of the three formulations and evaluates the impact of key problem parameters. We conclude that the proposed extended reformulations outperform the standard formulation for a majority of the instances. We also provide insights on the impact of the problem parameters on the computational performance. 相似文献
244.
Y. Abu Muhanna Rosihan M. Ali Zhen Chuan Ng Siti Farah M. Hasni 《Journal of Mathematical Analysis and Applications》2014
The class consisting of analytic functions f in the unit disk satisfying f+αzf′+γz2f″ subordinated to some function h is considered. The Bohr radius for this class is obtained when h is respectively convex or starlike. The Bohr radius for analytic functions mapping the unit disk into a concave-wedge domain as well as for bounded harmonic mappings are also established. 相似文献
245.
Farah Bouakrif 《Complexity》2013,19(1):37-45
This article presents a state observer based iterative learning control to solve the trajectory tracking problem of a class of time‐varying Multi‐Input‐Multi‐Output nonlinear systems with arbitrary relative degree. For this purpose, an asymptotically stable observer is derived for the system under consideration. There after, this observer is integrated with the iterative learning controller by replacing the state in the control law with its estimation yielded by the state observer. Hence, the stability of the whole control (nonlinear system plus controller plus observer) is guaranteed. Simulation result on nonlinear system shows that the trajectory tracking error decreases through the iterations. © 2013 Wiley Periodicals, Inc. Complexity 19: 37–45, 2013 相似文献
246.
Non-equilibrium argon-nitrogen mixture plasma generated at 13.56 MHz is characterized by optical emission spectroscopy and Langmuir probe techniques. The excitation and vibrational temperature are studied as a function of argon percentage in the mixture, at 30-Pa filling pressure and input RF powers of 200 and 300 watt, to find out their role in dissociation of N2 molecules. In this work, the excitation temperature is determined from Ar-I emission line intensities by using the simple Boltzmann plot method and is found to increase with argon mixing in nitrogen plasma. In similar fashion, the vibrational temperature of second positive system has been determined and is found to also have increasing trend with argon addition. The effect of excitation and vibrational temperature on the nitrogen molecular dissociation level is also monitored. It is observed that N/N 2 ratio increases with increase in excitation and vibrational temperature and falls slightly at the end. 相似文献
247.
The conservation laws for Prandtl’s boundary layer equations for an incompressible fluid governing the flow in radial and two-dimensional jets are investigated. For both radial and two-dimensional jets the partial Lagrangian method is used to derive conservation laws for the system of two differential equations for the velocity components. The Lie point symmetries are calculated for both cases and a symmetry is associated with the conserved vector that is used to establish the conserved quantity for the jet. This associated symmetry is then used to derive the group invariant solution for the system governing the flow in the free jet. 相似文献
248.
We consider a real semi-simple Lie group G with finite center and a maximal compact sub-group K of G. Let be a Cartan decomposition of G. For x∈G denote ∥x∥ the norm of the -component of x in the Cartan decomposition of G. Let and 1?p,q?∞. In this Note we give necessary and sufficient conditions on such that for all K-bi-invariant measurable function f on G, if ea∥x∥2f∈Lp(G) and then f=0 almost everywhere. To cite this article: S. Ben Farah, K. Mokni, C. R. Acad. Sci. Paris, Ser. I 336 (2003). 相似文献
249.
The distribution of Zr(IV) between hydrochloric acid media and Hyamine 1622 in the organic phase is described. The dependence of extraction on acidity, extractant concentration and type of diluent, was investigated. The possible extraction mechanism is discussed in the light of the results obtained. A method for the separation and determination of Zr(IV) in a mixture of Zr and Hf is outlined. 相似文献
250.
Rosa indica symbol of godness and beauty known for various healing power, has astringent, sedative, anti-inflammatory and antidepressant qualities. Standard methods were used for qualitative detection of phyto-compounds, and quantitative detection of antioxidants was done using DPPH radical scavenging assay, total phenolics and total flavonoids content were expressed in mg GAE/g dry weight and mg QE/g dry weight. Results revealed phyto-compounds presence in all varieties under study however maximum % inhibition was observed by R. indica var pink perfume (94 ± 0.6) with IC50 value 0.3376 ± 0.01 mg/mL. Highest phenolic and flavonoid content was observed in the leaves extract of R. indica var cardinal red, i.e. 3.3553 ± 0.11 (ethanol) mg of Gallic acid equivalents (GAE)/g dry weight and 3.736 ± 0.001(ethanol) mg of quercetin equivalents (QE)/g dry weight, respectively, at conc. 0.125 mg/mL. Our finding provides evidence that all varieties of rose contain medicinally important bioactive compounds and justifies their use for treatment of different diseases. 相似文献