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111.
Prasad S 《Journal of the Optical Society of America. A, Optics, image science, and vision》2004,21(11):2073-2088
The question of just how much to defocus the second image in the conventional two-channel phase-diversity speckle imaging technique may be addressed in a number of ways. Fisher information furnishes a useful metric for optimizing the choice of defocus as a functional of the object class, operating conditions, and the imaging task. Approximate closed-form expressions for the Fisher information relative to object parameters, rather than the pupil phase, are derived and discussed for phase-diversity-speckle imaging under conditions of strong turbulence and additive Gaussian noise. As an application of our general information-theoretic approach, the optimization of defocus when the imaging task is to estimate the midfrequency power spectrum of the object is discussed. 相似文献
112.
Sudhakar T. Natarajan V. Gopinath M. Saranyadevi J. 《Wireless Personal Communications》2020,115(4):2779-2803
Wireless Personal Communications - In the past two decades, numerous two-factor authentication protocols have been proposed for the multi-server environment using a smart card and password. Sahoo... 相似文献
113.
Reema Sarkari Chatla AnjaneyuluVankudoth Krishna Ramineni KishoreMedak Sudhakar Akula Venugopal 《Catalysis communications》2011,12(12):1067-1070
A novel method has been developed for the synthesis of methylpyrazine (MP) by using aqueous glycerol and ethylenediamine (EDA) over Zn–Cr catalyst derived from hydrotalcite precursors. The X-ray diffraction analysis of the oven-dried Zn–Cr samples synthesized at various pH ranging from 7 to 11 showed hydrotalcite phase whereas the calcined catalysts displayed ZnO and ZnCr2O4 phases. The cyclisation activity of Zn–Cr catalyst prepared at pH ~ 9 demonstrated 99.4% conversion of EDA and 94% of glycerol with ~ 72% selectivity to MP at a reaction temperature of 400 °C. This process demonstrates direct utilization of bio-glycerol for the synthesis of MP. 相似文献
114.
S. Sailaja S. J. Dhoble Nameeta Brahme B. Sudhakar Reddy 《Journal of Materials Science》2011,46(24):7793-7798
A new series of Eu3+ ions-activated calcium gadolinium tungstate [Ca2Gd2W3O14] phosphors were synthesized by conventional solid-state reaction method. The X-ray diffraction patterns of the powder samples
indicate that the Eu3+: Ca2Gd2W3O14 phosphors are of tetragonal structure. The prepared phosphors were well characterized by scanning electron microscopy (SEM),
energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL), and mechanoluminescence
(ML) spectra. PL spectra of Eu3+: Ca2Gd2W3O14 powder phosphors have shown strong red emission at 615 nm (5D0 → 7F2) with an excitation wavelength λ
exci = 392 nm (7F0 → 5L6). The energy transfer from tungstate groups to europium ions has also reported. Mechanoluminescence studies of Eu3+: Ca2Gd2W3O14 phosphors have also been explained systematically. 相似文献
115.
Biradar S Ravichandran P Gopikrishnan R Goornavar V Hall JC Ramesh V Baluchamy S Jeffers RB Ramesh GT 《Journal of nanoscience and nanotechnology》2011,11(8):6868-6874
The synthesis of nanoparticles and their functionalization to effectively utilize them in biological applications including drug delivery is currently a challenge. Calcium carbonate among many other inorganic nanosized particles offers promising results for such applications. We have synthesized calcium carbonate nanoparticles using polymer mediated growth technique, where one of the ions bound within polymer matrix and the other diffuses and reacts to form desired compound. The synthesized nanoparticles are characterized using X-ray diffraction, Scanning Electron Microscopy and spectroscopic techniques such as Fourier-Transform Infra-red spectroscopy and UV-Vis spectroscopy. The diameter of the calcium carbonate nanoparticles is estimated to be 39.8 nm and their biocompatibility studies showed no significant induction of oxidative stress or cell death even at higher concentrations (50 microg) upon exposure to HeLa and LE cells. Here, we report that the synthesized calcium carbonate nanosized particles using polymer mediated growth technique are biocompatible and can be safely used for biomedical applications. 相似文献
116.
Sangeeta Verma Dr. Sukhbir Lal Dr. Rakesh Narang Dr. Kalvatala Sudhakar 《ChemMedChem》2023,18(5):e202200571
Antibiotics are becoming gradually ineffective due to drug resistance, leading to greater difficulty in the treatment of infectious diseases. Therefore, the development of new chemical entities with different mechanisms of action is essential in the fight against resistant microorganisms. Various studies have shown that quinoline hydrazide/hydrazone derivatives possess several biological activities, such as antimalarial, antitubercular, anticancer, anti-inflammatory, and antimicrobial. Among these activities, the antibacterial activity of quinoline hydrazide/hydrazone derivatives is noteworthy. The synthetic flexibility of the quinoline ring has led to the development of a wide range of structurally diverse quinoline hydrazide/hydrazone derivatives, which can act at various bacterial targets such as DNA gyrase, glucosamine-6-phosphate synthase, enoyl ACP reductase, and 3-ketoacyl ACP reductase. This review emphasizes the antibacterial potential of various reported quinoline hydrazide/hydrazone derivatives based on substitution in the quinoline ring. The antibacterial activity of various metal-quinoline hydrazide/hydrazone complexes is also discussed. The aim of this review is to assemble and scrutinize the latest reports in this promising area of drug development. 相似文献
117.
Sudhakar Yerramareddy Stephen C-Y. Lu Karl F. Arnold 《Journal of Intelligent Manufacturing》1993,4(1):33-41
Computer-integrated manufacturing requires models of manufacturing processes to be implemented on the computer. Process models are required for designing adaptive control systems and selecting optimal parameters during process planning. Mechanistic models developed from the principles of machining science are useful for implementing on a computer. However, in spite of the progress being made in mechanistic process modeling, accurate models are not yet available for many manufacturing processes. Empirical models derived from experimental data still play a major role in manufacturing process modeling. Generally, statistical regression techniques are used for developing such models. However, these techniques suffer from several disadvantages. The structure (the significant terms) of the regression model needs to be decided a priori. These techniques cannot be used for incrementally improving models as new data becomes available. This limitation is particularly crucial in light of the advances in sensor technology that allow economical on-line collection of manufacturing data. In this paper, we explore the use of artificial neural networks (ANN) for developing empirical models from experimental data for a machining process. These models are compared with polynomial regression models to assess the applicability of ANN as a model-building tool for computer-integrated manufacturing.Operated for the United States Department of Energy under contract No. DE-AC04-76-DP00613. 相似文献
118.
The selective oxidation of cyclohexane to cyclohexanol and cyclohexanone using hydrogen peroxide has been studied over TS-2, a titanium silicate molecular sieve with a MEL structure. The reaction is found to be catalyzed by the Ti present in the framework structure, the activity being proportional to the Ti content. 相似文献
119.
Brian Morgan Brent R. Stockwell David R. Dodds David R. Andrews Anantha R. Sudhakar Christopher M. Nielsen Ingrid Mergelsberg Arne Zumbach 《Journal of the American Oil Chemists' Society》1997,74(11):1361-1370
Chemoenzymatic approaches to the synthesis of two key chiral-precursors of a new azole antifungal agent, SCH 56592, are described.
In particular, the enzymatic diastereoselective acylation of 2-benzyloxy-3-pentanol (7) was developed to produce (2S;3R)-7 in >97% diastereomeric excess (de) from otherwise unusable mixtures of (2S,3R)/(2S,3S)-7 (40–80% de). The selectivity and reactivity of commercially available Candida rugosa and Mucor miehei lipases are compared for the acylation of 7 and the hydrolysis of the corresponding butyrate 16a. Of the 17 C. rugosa enzyme preparations that were examined for acylation of 7, two purified enzyme preparations showed no reactivity, five enzymes
showed high diastereoselectivity with preference for the (2S,3R)-isomer, and seven showed a slight preference for the (2S,3S)-isomer. 相似文献
120.