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排序方式: 共有147条查询结果,搜索用时 203 毫秒
101.
102.
M.J. Tait A.A. El Damatty N. Isyumov M.R. Siddique 《Journal of Fluids and Structures》2005,20(8):1007-1023
The tuned liquid damper (TLD) is increasingly being used as an economical and effective dynamic vibration absorber to mitigate the dynamic response of structures. In this paper the results of two numerical flow models of TLD behaviour are compared with experimental data. These include the free surface motion, the resulting base shear forces, and the energy dissipated by a TLD with slat screens. The importance of this experimental study is that it examines TLD behaviour over a large range of normalized excitation amplitude values, covering the practical range of serviceability accelerations for buildings subjected to wind loads and larger excitation amplitudes more representative of earthquake motion. In addition, the experimental results are used to assess the models for larger fluid depth to tank length values, and for the use of modelling TLDs equipped with multiple screens. For screens consisting of a number of thin plate slats, a method for determining the loss coefficient is presented, which is a required parameter for the models used in this paper. Findings indicate that the linear model is capable of providing an initial estimate of the energy dissipating characteristics of a TLD. The nonlinear model can accurately describe the response characteristics within the range of excitation amplitudes experimentally tested. 相似文献
103.
Ameer Fawad Zahoor Muhammad Yousaf Rabia Siddique Sajjad Ahmad Syed Ali Raza Naqvi Sayyad Muhammad Ali Rizvi 《合成通讯》2017,47(11):1021-1039
Enoxacin, levofloxacin, and gatifloxacin represent one of the most important prerogative scaffolds in drug development. They possess broad spectrum antimicrobial and anti-inflammatory activities. They inhibit bacterial growth by blocking their topoisomerase enzyme which is necessary for the proper functioning of bacterial DNA. In this article, we have reviewed the synthetic approaches involved in the synthesis of derivatives of enoxacin, levofloxacin, and gatifloxacin. 相似文献
104.
This paper deals with the rotational flow of a generalized second grade fluid, within a circular cylinder, due to a torsional shear stress. The fractional calculus approach in the constitutive relationship model of a second grade fluid is introduced. The velocity field and the resulting shear stress are determined by means of the Laplace and finite Hankel transforms to satisfy all imposed initial and boundary conditions. The solutions corresponding to second grade fluids as well as those for Newtonian fluids are obtained as limiting cases of our general solutions. The influence of the fractional coefficient on the velocity of the fluid is also analyzed by graphical illustrations. 相似文献
105.
A facile, green, and efficient Fe(III) chloride, one-pot, multicomponent reaction (MCR) for synthesis of 2-aminothiazole-based compounds is reported. Considering the medicinal importance of fused ring 2-aminothiazoles, this process provides an easy route to the synthesis of this class of compound. Detailed mechanism of the reaction has been discussed. 相似文献
106.
The ultrasonic velocity (U), has been measured for three α‐amino acids, namely L‐lysine monohydrochloride, L‐arginine and L‐histidine in solutions (1 mol/L aqueous) of sodium acetate (SA), potassium acetate (PA) and calcium acetate (CA) at different temperatures (303.15, 308.15, 313.15, 318.15 and 323.15 K). With the help of these results various ultrasonic derived parameters, viz. isentropic compressibility (κs), change in isentropic compressibility (Δκs), relative change in isentropic compressibility (Δκr), specific acoustic impedance (Z), relative association (RA), and apparent molal compressibility (?) have been estimated. The results have been interpreted in the light of intermolecular interactions between solute and solvent. 相似文献
107.
S.?WaheedEmail author S.?Rahman S.?M.?Husnain N.?Siddique 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(3):937-945
Instrumental Neutron Activation Analysis (INAA) and Atomic Absorption Spectroscopy methodology was developed to characterize
the hazardous and other inorganic trace element constituents in new and used domestic plastic food containers. INAA due to
its non destructive, highly sensitive, multielement and low detection limits characteristics was found to be a good technique
for the characterization of polymeric products. Through the variation of irradiation, cooling and counting protocols Al, Ba,
Br, Co, Cr, Eu, Fe, Hg, K, Mn, Na, Nd, Sb, Sc, Th, Ti, V and Zn were determined, while Atomic Absorption Spectroscopy was
used as complementary technique to quantify toxic inorganic elements such as Cd, Pb and Cu. These elements are thought to
originate from the polymer manufacturing processes. It was found that there was gradual increase in the concentration of most
of these elements from new to used plastic samples. Moreover it was also observed that these inorganic elements are present
in higher concentrations in the lower grade containers as compared to the high quality containers. It was also observed that
the good quality containers even with the long usage do not degrade to such an extent as the low quality containers. 相似文献
108.
The traditional standard stochastic system models, such as the autoregressive (AR), moving average (MA) and autoregressive moving average (ARMA) models, usually assume the Gaussian property for the fluctuation distribution, and the well-known least squares method is applied on the basis of only the linear correlation data. In the actual sound environment system, the stochastic process exhibits various non-Gaussian distributions, and there exist potentially various nonlinear correlations in addition to the linear correlation between input and output time series. Consequently, the system input and output relationship in the actual phenomenon cannot be represented by a simple model. In this study, a prediction method of output response probability for sound environment systems is derived by introducing a correction method based on the stochastic regression and fuzzy inference for simplified standard system models. The proposed method is applied to the actual data in a sound environment system, and the practical usefulness is verified. 相似文献
109.
Bimal B. Chakraborty Siddique Anwar Saurav Das Satya B. Paul Golam Mohiuddin Joydip De 《Liquid crystals》2018,45(11):1644-1653
In this work, hydrogen-bonded liquid crystal exhibiting phase dependent fluorescence has been reported. The H-bonded materials were prepared using pyridenyl benzothiazole and alkoxy benzoic acid as H-bond acceptor and donor respectively. The formation of the target materials was confirmed via different spectroscopic technique and their mesogenic behaviour has been studied through polarising optical microscope, differential scanning calorimetry and 2D-X-ray diffraction. The H-bonded mesogenic material showed aggregation dependent fluorescence switching when subjected to transformation from isotropic-nematic-crystalline phase sequence. Computational studies were performed to probe into fluorescence switching behaviour of the mesogenic material. 相似文献
110.
Summary Rahman A. Elérhetoség Intézet neve Intézet címe E-mail 相似文献