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171.
ABSTRACTWhen a pulsed laser gets tightly focused onto a target-liquid interface, plasma formation occurs which leads to nucleation of nanoparticles based on the choice of target and its affinity to the surrounding liquid. Here, we report the generation of Titanium Oxide nanoparticles at titanium–water interface from defocused diverging laser beam rather than from converging tightly focused beam. This is done to tackle the laser-induced fragmentation of ejected nanoparticles in the beam path which widens the nanoparticulate statistics as laser energy gets consumed by the nanoparticles thereby causing a reduction in the ablation efficiency of the target material. The use of diverging laser beam effectively takes most of the ablated species away from the beam path and improvises on the ablation phenomena with yield up to 4?mg/h. The utility of the derived nanoparticulates under such conditions is then checked from its photocatalytic activity which shows 70% photodegradation of environmental pollutants. 相似文献
172.
173.
174.
Khare P Gupta AK Gajula PK Sunkari KY Jaiswal AK Das S Bajpai P Chakraborty TK Dube A Saxena AK 《Journal of chemical information and modeling》2012,52(3):777-791
The present study describes a successful application of computational approaches to identify novel Leishmania donovani (Ld) AdoHcyase inhibitors utilizing the differences for Ld AdoHcyase NAD(+) binding between human and Ld parasite. The development and validation of the three-dimensional (3D) structures of Ld AdoHcyase using the L. major AdoHcyase as template has been carried out. At the same time, cloning of the Ld AdoHcyase gene from clinical strains, its overexpression and purification have been performed. Further, the model was used in combined docking and molecular dynamics studies to validate the binding site of NAD in Ld. The hierarchical structure based virtual screening followed by the synthesis of five active hits and enzyme inhibition assay has resulted in the identification of novel Ld AdoHcyase inhibitors. The most potent inhibitor, compound 5, may serve as a "lead" for developing more potent Ld AdoHcy hydrolase inhibitors as potential antileishmanial agents. 相似文献
175.
Coupled discrete models are ubiquitous in a variety of physical contexts. We provide an extensive set of exact quasiperiodic solutions of a number of coupled discrete models in terms of Lamé polynomials of arbitrary order. The models discussed are: (i) coupled Salerno model, (ii) coupled Ablowitz?CLadik model, (iii) coupled ? 4 model and (iv) coupled ? 6 model. In all these cases we show that the coefficients of the Lamé polynomials are such that the Lamé polynomials can be re-expressed in terms of Chebyshev polynomials of the relevant Jacobi elliptic function. 相似文献
176.
177.
A single artificial grain boundary in La0.67Ba0.33MnO3 (LBMO) thin film has been prepared by depositing the film on a bicrystal substrate using laser ablation technique. We investigated the magnetic field dependence of magnetoresistance and conductance-voltage characteristics of the grain boundary at 77 K. A decrease of nonlinearity of current-voltage characteristics was observed upon application of magnetic field. The results are explained by assuming the presence of two different types of parallel conducting channels (metallic and highly resistive) across the grain boundary. The analysis of the results reveals that the application of magnetic field suppresses magnetic disorders at the grain boundary region and increases metallic conduction channels across the grain boundary. The temperature dependence of the conduction noise of the bicrystal grain boundary was measured at 0 and 1.5 kG magnetic field and compared with a microbridge on the LBMO film having no grain boundary. The presence of the grain boundary was found to enhance noise by one order of magnitude. The noise of a bicrystal grain boundary showed a decrease in the presence of 1.5 kG magnetic field for T<210 K. This decrease of noise confirms that the application of a magnetic field induces more metallic channels across the grain boundary. 相似文献
178.
The generation of harmonics in a laser ablated YBCO film deposited on a 〈100〉 MgO substrate is reported. Higher odd harmonics
appeared when the film was subjected to an ac field. The presence of a dc field induces only the second harmonic with a small
value of slope ofV
2−H
dc curve (δV
2/δH
dc) compared to bulk YBCO. The variation of the amplitude of third harmonic (V
3) withH
ac and temperature was studied. These results are explained in terms of a critical state model. The observation of only a small
amplitude of second harmonic (V
2) with a smallδV
2/δH
dc is explained in terms of a special kind of clean grain boundary present in YBCO laser ablated films on 〈100〉 MgO. 相似文献
179.
Paulius Mikulskis Daniela Cioloboc Milica Andrejić Sakshi Khare Joakim Brorsson Samuel Genheden Ricardo A. Mata Pär Söderhjelm Ulf Ryde 《Journal of computer-aided molecular design》2014,28(4):375-400
We have estimated free energies for the binding of nine cyclic carboxylate guest molecules to the octa-acid host in the SAMPL4 blind-test challenge with four different approaches. First, we used standard free-energy perturbation calculations of relative binding affinities, performed at the molecular-mechanics (MM) level with TIP3P waters, the GAFF force field, and two different sets of charges for the host and the guest, obtained either with the restrained electrostatic potential or AM1-BCC methods. Both charge sets give good and nearly identical results, with a mean absolute deviation (MAD) of 4 kJ/mol and a correlation coefficient (R 2) of 0.8 compared to experimental results. Second, we tried to improve these predictions with 28,800 density-functional theory (DFT) calculations for selected snapshots and the non-Boltzmann Bennett acceptance-ratio method, but this led to much worse results, probably because of a too large difference between the MM and DFT potential-energy functions. Third, we tried to calculate absolute affinities using minimised DFT structures. This gave intermediate-quality results with MADs of 5–9 kJ/mol and R 2 = 0.6–0.8, depending on how the structures were obtained. Finally, we tried to improve these results using local coupled-cluster calculations with single and double excitations, and non-iterative perturbative treatment of triple excitations (LCCSD(T0)), employing the polarisable multipole interactions with supermolecular pairs approach. Unfortunately, this only degraded the predictions, probably because of a mismatch between the solvation energies obtained at the DFT and LCCSD(T0) levels. 相似文献
180.
Pankaj Kumar J. K. Pattanaik N. Khare S. Chopra S. Yadav S. Balakrishnan D. Kanjilal 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(2):903-909
The distribution of 10Be, as well as the major elements concentrations and the grain size in surface and core sediment samples, collected from Krossfjorden and Kongsfjorden, Svalbard have been studied for understanding the origin of 10Be and an estimation of its accumulation rate. The 10Be concentration in sediments varies between 0.90 × 108 and 2.53 × 108 atoms g?1. Our results show that atmospherically produced 10Be dominates over terrigenous (in situ) sources of 10Be in the studied samples. The calculated 10Be accumulation rate varies from 3.1 × 106 atoms cm?2 year?1 to 8.6 × 106 atoms cm?2 year?1 which is higher than the accumulation rate observed in the deep sea sediment cores of the Arctic Ocean and the Norwegian Sea. The higher accumulation rate of 10Be is attributed to the higher influx of glacier melt water into the fjord system. 相似文献