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1.
Product integration rules generalizing the Fej?r, Clenshaw-Curtis,and Filippi quadrature rules respectively are derived for integralswith trigonometric and hyperbolic weight factors. The Chebyshevmoments of the weight functions are found to be given by well-conditionedexpressions, in terms of hypergeometric functions 0F1. An a priori error estimator is discussed which is shown bothto avoid wasteful invocation of the integration rule and toincrease significantly the robustness of the automatic quadratureprocedure. Then, specializing to extended Clenshaw-Curtis (ECC) rules,three types of a posteriori error estimates are considered andthe existence of a great risk of their failure is demonstratedby large scale validation tests. An empirical error estimator,superseding them for slowly varying integrands, is found toresult in a spectacular increase in the output reliability. Finally, enhancements in the control of the interval subdivisionstrategy aiming at increasing code robustness is discussed.Comparison with the code DQAWO of QUADPACK, with about a hundredthousand solved integrals, is illustrative of the increasedrobustness and error estimate reliability of our computer codeimplementation of the ECC rules. 相似文献
2.
S.L. Gaonkar 《Tetrahedron letters》2005,46(35):5969-5970
The reaction of ketohydrazones containing an α-methylene group with chloramine-T followed by treatment with triethylamine leads to the formation of azoalkenes via an α-chloroazo-compound, which can react intermolecularly and in situ with olefinic compounds to produce tetrahydropyridazine derivatives in good yield. 相似文献
3.
BAGHERI GH Azar 《中国化学》2009,27(6):1073-1078
The complexation of zinc(II) with dopamine has been investigated by spectrophotometric measurements in mixed solvent system at an ionic strength of 0.2 mol•dm-3 sodium chloride, employed at at (15±0.1), (25±0.1), (35±0.1) ℃ at inin a pH range of ca. 6 to ca. 7 with a high ratio of ligand to metal. The effect of solvent systems on protonation and complexation are was was discussed. Linear relationships are werewere observed by plotting lg K versus 1/D, where K and D show stability and dielectric constants, respectively. 相似文献
4.
Mohan-Kumari H. Puttananjaiah Mohan Appasaheb Dhale Vaishali Gaonkar Shradha Keni 《Applied biochemistry and biotechnology》2011,163(2):215-222
Atherosclerosis is a chronic inflammatory disease of multiple etiologies. It is associated with the accumulation of oxidized
lipids in arterial lesions leading to coronary heart disease. 3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors
(commonly known as statins) are widely used in cardiovascular disease prevention to lower the cholesterol. The antioxidant
activity of HMG-CoA reductase inhibitors was studied by lipid peroxidation inhibition assay, DPPH, and hydroxyl radical scavenging-activity
methods. The lovastatin (93%) and simvastatin (96%) showed significant action of lipid peroxidation inhibition compared to
other HMG-CoA reductase inhibitors. The DPPH radical and hydroxyl radical scavenging activity of simvastatin was 38% and 33%,
respectively. The oxidative modification of serum lipid due to reactive oxygen species causes atherosclerosis. This study
revealed the importance of lovastatin and simvastatin to prevent oxidative stress-related cardiovascular diseases. 相似文献
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6.
GH. R. Kefayati 《Theoretical and Computational Fluid Dynamics》2013,27(6):865-883
In this paper, the effects of a magnetic field on natural convection flow in filled long enclosures with Cu/water nanofluid have been analyzed by lattice Boltzmann method. This study has been carried out for the pertinent parameters in the following ranges: the Rayleigh number of base fluid, Ra = 103–105, the volumetric fraction of nanoparticles between 0 and 6 %, the aspect ratio of the enclosure between A = 0.5 and 2. The Hartmann number has been varied from Ha = 0 to 90 with interval 30 while the magnetic field is considered at inclination angles of θ = 0°, 30°, 60° and 90°. Results show that the heat transfer decreases by the increment of Hartmann number for various Rayleigh numbers and the aspect ratios. Heat transfer decreases with the growth of the aspect ratio but this growth causes the effect of the nanoparticles to increase. The magnetic field augments the effect of the nanoparticles at high Rayleigh numbers (Ra = 105). The effect of the nanoparticles rises for high Hartmann numbers when the aspect ratio increases. The rise in the magnetic field inclination improves heat transfer at aspect ratio of A = 0.5. 相似文献
7.
A personal computer (PC)-based data acquisition and instrument control system has been developed for neutron spectrometers
in Dhruva reactor hall and Guide Tube laboratory. Efforts have been made to make the system versatile so that it can be used
for controlling various neutron spectrometers using single end-on detector in step scan mode. Commercially available PC add-on
cards have been used for input-output and timer-counter operations. An interface card and DC motor driver card have been developed
indigenously. Software for the system has been written in Visual C++ language using MS Windows operating system. This data
acquisition and instrument control system is successfully controlling four spectrometers at Dhruva reactor. 相似文献
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Chalcones and their analogs have been an area of great interest in recent years. Numerous research papers have been published, and chalcones continue to show promise for new drug investigations. Researchers have explored new approaches for the synthesis of chalcone derivatives, which have revealed an array of pharmacological and biological effects. These chalcone derivatives have shown important antimicrobial, antifungal, anti-mycobacterial, antimalarial, antiviral, anti-inflammatory, antioxidant, antileishmanial anti-tumor, and anticancer properties. This review highlights the synthesis and pharmacological properties of chalcone derivatives. 相似文献
10.
Santosh L. Gaonkar 《Tetrahedron》2010,66(18):3314-3317
We developed a simple, rapid, high yielding, and environmentally benign microwave assisted total synthesis of rosiglitazone, an antihyperglycemic agent for diabetes mellitus Type II. We used microwave heating successfully to improve reactions in four of six steps and obtain quicker and higher yields. In addition, all intermediates were isolated in good yields with crystallizations only and did not require chromatographic separations. 相似文献