排序方式: 共有49条查询结果,搜索用时 468 毫秒
31.
Kerehalli Vinayaka Prasad Hanumesh Vaidya Fateh Mebarek Oudina Khalid Mustafa Ramadan Muhammad Ijaz Khan Rajashekhar Choudhari Rathod Kirankumar Gulab Iskander Tlili Kamel Guedri Ahmed M. Galal 《印度化学会志》2022,99(8):100617
Due to the illuminating function of nanoliquids in several technological and medicinal domains, particularly in liquid transport processes known as peristalsis, inquisitive researchers have investigated the flow of peristaltic nanofluids. Consequently, the current study investigates the entropy production and magnetic influence on the peristaltic transport of heat and mass transport of Casson nanofluid in a non-uniform channel under convective circumstances. Utilizing the perturbation approach, fields of concentration, temperature, and velocity are derived from non-linear coupled partial differential equations (PDE). Entropy generation studies have been done. In addition, the influence of associated factors via specific physical terms, including the Sherwood number, the skin-friction coefficient, and the Nusselt number, for both Casson and Newtonian liquids, as well as the trapping phenomena, is visually examined. 相似文献
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This paper presents a novel robust decentralized control of electrically driven robot manipulators by adaptive fuzzy estimation and compensation of uncertainty. The proposed control employs voltage control strategy, which is simpler and more efficient than the conventional strategy, the so-called torque control strategy, due to being free from manipulator dynamics. It is verified that the proposed adaptive fuzzy system can model the uncertainty as a nonlinear function of the joint position error and its time derivative. The adaptive fuzzy system has an advantage that does not employ all system states to estimate the uncertainty. The stability analysis, performance evaluation, and simulation results are presented to verify the effectiveness of the method. A?comparison between the proposed Nonlinear Adaptive Fuzzy Control (NAFC) and a Robust Nonlinear Control (RNC) is presented. Both control approaches are robust with a very good tracking performance. The NAFC is superior to the RNC in the face of smooth uncertainty. In contrast, the RNC is superior to the NAFC in the face of sudden changes in uncertainty. The case study is an articulated manipulator driven by permanent magnet dc motors. 相似文献
33.
Goel A Singh FV Kumar V Reichert M Gulder TA Bringmann G 《The Journal of organic chemistry》2007,72(20):7765-7768
A one-pot general synthesis of highly functionalized quateraryls through carbanion-induced, base-catalyzed ring transformation of 5,6-diaryl-2H-pyran-2-ones and core-substituted phenylacetones is delineated. These conversions were found to give diversely functionalized benzenes bearing peripheral aryl rings, some of which possess inherent atropisomerism. Exemplarily for one of the quateraryls, the optical resolution of the respective atropo-enantiomers by HPLC on a chiral phase and the assignment of their absolute axial configurations succeeded by LC-CD coupling in combination with semiempirical CNDO/S and TDDFT CD calculations. This synthetic approach offers-in a transition metal-free environment-high flexibility in the construction of quateraryls with the desired conformational freedom along the molecular axis, which may help in exploring and developing new potential ligands for asymmetric synthesis. 相似文献
34.
Development of peptides as clinically useful drugs is limited by their poor metabolic stability and low bioavailability. Recent progresses in chemical synthesis and design have led to several strategies for producing potent mimetics. This study aims to analyze sequence/structure requirements and composition for antimicrobial peptoid designs, as use of peptoids is one of the most representative approaches to meet the goal of biomimicry. Analysis of the designs showed that for maximum activity and minimum hemolysis, the plane of the aromatic residues should be at an angle between 0 and 90 ° with respect to membranes, cationic residues need not be at the terminal position, and central positions should be uniform in NIle, NLys, and NPhe residues.
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This paper is concerned with the problem of design and implementation of a robust adaptive control strategy for electrically driven robots while considering to the constraints on the actuator voltage input. The proposed approach provides a flexible design framework and stable to deal with robustness compared with many other adaptive controllers, such as halting/slowing adaption techniques and adaptively adjusting command signal, which are proposed for robotic applications. The control design procedure is based on a new form of universal approximation theory and using Stone–Weierstrass theorem, to avoid saturation besides being robust against both structured and unstructured uncertainties associated with external disturbances and actuated manipulator dynamics. Moreover, the proposed approach eliminates problems arising from classic adaptive feedforward control scheme. The analytical studies as well as experimental results produced using MATLAB/SIMULINK external mode control on a two degree of freedom electrically driven robot demonstrate high performance of the proposed control schemes. 相似文献
37.
An innovative synthesis of terphenyls functionalized with electron-withdrawing or -donating substituents is described and illustrated by carbanion-induced ring transformation of 2H-pyran-2-ones with 2-methoxyacetophenone in excellent yields. The existing protocols for the synthesis of terphenyls are generally inter- and intramolecular aryl-aryl cross couplings in the presence of metal complexes. In this letter, we report a potentially useful alternative to conventional metal-catalyzed cross-coupling reactions. 相似文献
38.
The band gap in cadmium zinc phosphate glass samples with composition 35 mol% CdO-5 mol% ZnO-60 mol% P2O5 has been determined by absorption and photoconduction measurements. The two values of the band gap are nearly the same within the experimental error. The photoconductive band gap shows a slow decrease with an increase in the applied field. The results have been discussed in terms of the energy band model for non-crystalline solids. 相似文献
39.
Nonlinear Dynamics - In this article stabilization of fractional-order periodic discrete-time linear system by a complete nonlinear parametric approach for pole assignment with respect to stability... 相似文献
40.
Fateh Chebana 《Comptes Rendus Mathematique》2004,338(4):311-316
The goal of this work is to establish the limit distribution of the process where is a class of weight functions W, fn is the kernel density estimator of the density f and A is a Borelian subset of . We apply this result to derive new statistics to test goodness-of-fit of the density function f. Under some local alternatives, these new tests are more powerful than the usual Bickel–Rosenblatt one. To cite this article: F. Chebana, C. R. Acad. Sci. Paris, Ser. I 338 (2004). 相似文献