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61.
A semi-analytical distributed transfer function (DTF) approach is proposed for the free-vibration analysis of moderately thick cantilever beams with a single surface-bonded piezoelectric patch. The asymmetric piezoelectric adaptive structure is decomposed into three segments; the first and third segments are bare beam parts before and after the patch, while the second segment contains the beam part with attached piezoelectric patch bonded to its upper surface. The theoretical formulation assumes first-order shear deformation kinematics and linear electric potential through the patch thickness with an electrode equipotential physical condition, and uses the extended Hamilton?s principle to derive the equations of motion and electromechanical boundary conditions. The latter, together with the continuity and equilibrium conditions at the segments interfaces, are then transformed into a first-order state space equation that is solved using the DTF approach. The electrodes of the piezoelectric patch are considered either in short-circuit (SC) or open-circuit (OC); this leads to two free-vibration problems to be solved for the corresponding SC and OC frequencies, from which the Electro-Mechanical Coupling Coefficient (EMCC) is post-treated. Four benchmarks from the open literature are simulated in order to validate the proposed approach. Very satisfactory correlations are obtained for all examples with maximum errors less thank 5 percent in all results. For future reference, an additional benchmark is proposed to assess the influence of the patch-to-composite host width ratio on the effective modal EMCC. It was found that the latter is mode-dependent (as expected) and decreases with increasing the former. 相似文献
62.
Abdul Majeed SeayadKumaravel Selvakumar Moballigh AhmedMatthias Beller 《Tetrahedron letters》2003,44(8):1679-1683
Hydroaminomethylation of terminal as well as internal aliphatic and aromatic olefins with various amines is described in the presence of [Rh(cod)(Imes)Cl] as a catalyst. In general good to excellent yields and high chemoselectivity were obtained in THF at 85-105°C using 0.1 mol% of catalyst. 相似文献
63.
Olav Vahtras Hans rgren Hans Jrgen AA. Jensen 《Journal of computational chemistry》1994,15(6):573-579
The evaluation of gradient vectors of a general operator with one-index, double-one-index, or higher-order one-index transformed integrals is a key operation in multiconfiguration response theory calculations. We describe an integral-driven direct algorithm that carries out this operation efficiently without pretransforming the integrals. The use of this algorithm leads to a considerable reduction in disk space and timing. © 1994 by John Wiley & Sons, Inc. 相似文献
64.
A new series of 6,8-dibromo-2-(4-chlorophenyl)quinazolin-4(3H)-one derivatives VI–XIII were synthesized. Their chemical structures were confirmed by spectral and elemental analysis. The cytotoxic effect of the newly synthesized compounds was tested in vitro against human breast cancer cell line (MCF-7). Most of the tested compounds have shown promising cytotoxic activity. Compounds X and XIIIb exerted a powerful cytotoxic effect against MCF-7 with a very low IC50 (0.0015 and 0.0047 µmol/ml), while compounds VI, VII, VIII, XIIb, XI, XIIIc and IX exerted a moderate cytotoxic effect (IC50 0.01523, 0.0213, 0.031, 0.0478, 0.049, 0.068 and 0.079 µmol/ml respectively), compared to doxorubicin (0.0025 µmol/ml). Exploring their apoptotic effect; interestingly,all compounds activated apoptotic cascade in MCF-7. Compounds VI, XIIIb, XIIb, XI, XIIa, VII, V and VIII showed potent effect even much more than doxorubicin by 12.87–5.91 folds, while compounds XIIIc, IX, XIIIa, XIIc and X showed moderate increase in CASP3 activity by 4.96–3.22 folds relative to untreated cells more or less similar to doxorubicin (5.57 folds). 相似文献
65.
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67.
Rajendran Ramanujam Savita Ganjihal Nagabushanam Kalyanam Muhammed Majeed 《Tetrahedron: Asymmetry》2013,24(11):663-668
The synthesis of chemically and enantiomerically pure (S)-3-amino tetrahydrofuran hydrochloride starting from the natural amino acids, l-aspartic acid or l-methionine is described. The process involves no chromatography and can be easily carried out on a large scale. The enantiopurity of the final product was established by NMR and chiral HPLC methods. 相似文献
68.
Obliquely propagating altra-low-frequency dust-electromagnetic waves in a self-gravitating, warm, magnetized, two fluid dusty
plasma system have been investigated. Two special cases, namely, dust-Alfvén mode propagating parallel to the external magnetic
field and dustmagnetosonic mode propagating perpendicular to the external magnetic field have also been considered. It has
been shown that effects of self-gravitational field, dust fluid temperature, and obliqueness significantly modify the dispersion
properties of these ultra-low-frequency dust-electromagnetic modes. It is also found that in parallel propagating dust-Alfvén
mode these effects play no role, but in obliquely propagating dust-Alfvén mode or perpendicular propagating dust-magnetosonic
mode the effect of self-gravitational field plays destabilizing role whereas the effect of dust/ion fluid temperature plays
stabilizing role. 相似文献
69.
Journal of Solid State Electrochemistry - We have deposited pure SnO2 and SnO2:Pd nanostructure films on the quartz and porous silicon PSi substrates using chemical spray pyrolysis technique to... 相似文献
70.
Soliman A. A. Attaby F. A. Alajrawy O. I. Majeed S. R. 《Journal of Thermal Analysis and Calorimetry》2019,138(4):2457-2468
Journal of Thermal Analysis and Calorimetry - The analysis of polymer chemical decomposition is often highly dependent on the test conditions. In fact, thermal analysis tends to be far more... 相似文献