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排序方式: 共有429条查询结果,搜索用时 15 毫秒
211.
V Chandrasekhar S Das R Yadav S Hossain R Parihar G Subramaniam P Sen 《Inorganic chemistry》2012,51(16):8664-8666
A new water-soluble, multisite-coordinating ligand LH(7) was prepared by the condensation of tris(hydroxymethyl)aminomethane with 2,6-diformyl-p-cresol. LH(7) is a selective chemosensor for Cu(2+), under physiological conditions, with visual detection limits of 20 ppm (ambient light conditions) and 4 ppm (UV light conditions). LH(7) can also be used in biological cell lines for the detection of Cu(2+). 相似文献
212.
213.
Mukherjee P Roy M Mandal BP Choudhury S Tewari R Tyagi AK Kale SP 《Journal of colloid and interface science》2012,367(1):148-152
Green synthesis of gold nanospheres with uniform diameter and triangular nanoprisms with optically flat surface was carried out using a non-pathogenic bio-control agent Trichoderma asperellum for reduction of HAuCl(4). Kinetics of the reaction was monitored by UV-Vis absorption spectroscopy. No additional capping/complexing agent was used for stabilizing the gold nanoparticles. Evolution of morphology from pseudospherical nanoparticles to triangular nanoprisms was studied by transmission electron microscopy (TEM). It revealed that three or more pseudospheres fused to form nanoprisms of different shapes and sizes. Slow rate of reduction of HAuCl(4) by constituents of cell-free fungal extract was instrumental in producing such exotic morphologies. Isolation of gold nanotriangles from the reacting masses was achieved by differential centrifugation. 相似文献
214.
Direct transfer of micro-molded electrodes for enhanced mass transport and water management in PEMFC
Ashvini B. Deshmukh Vinayak S. Kale Vishal M. Dhavale K. Sreekumar K. Vijayamohanan Manjusha V. Shelke 《Electrochemistry communications》2010,12(11):1638-1641
Soft lithography technique is used to micropattern the electrodes on the electrolyte membrane of polymer electrolyte fuel cell (PEMFC) in order to alleviate the issues due to poor water management and inadequate reactant distribution in the fuel cell environment. Membrane electrode assembly with the micropatterned electrode has shown an increase in power density at a higher temperature as well as at a higher relative humidity when compared to a flat electrode. Consistency in cell performance is observed in the case of micropatterned electrodes. 相似文献
215.
The present work describes a new, simple, and easy method for the generation of stable molecularly imprinted sites in polymeric film, combining self-assembled monolayer and Layer-by-layer approaches through thermal cross-linking of the layered structures, onto the surface of silver electrode. Modified silver electrodes demonstrate enantiodifferentiation and sensitive (detection limits 0.0060 ng mL(-1) for L- and 0.0062 for D-thyroxine) determination of d- and l-thyroxine with the help of differential pulse anodic stripping voltammetric technique. The binding kinetics of thyroxine was explored using anodic stripping cyclic voltammetry and chronocoulometry. The sensor was also validated for D- and L-thyroxine determinations in biological and pharmaceutical samples. 相似文献
216.
Synthesis of isofagomine has been achieved by implementation of aza-Claisen rearrangement of 2-C-hydroxymethyl glycals as a key step. The above rearrangement has also been utilized in the synthesis of biologically important polyhydroxylated piperidine frameworks such as isogalactofagomine, ent-isogalactofagomine and their analogues and some other azasugars as glycosidase inhibitors. 相似文献
217.
Mukherjee R Chaudhury K Das S Sengupta S Biswas P 《Micron (Oxford, England : 1993)》2012,43(9):937-947
ObjectiveSurface roughness parameters of various intraocular lenses (IOLs) biomaterials using atomic force microscopy (AFM) are compared. Variation, if any, in the micro-roughness properties of different IOLs made up of the same biomaterial is also explored. Retrospective analysis of posterior capsular opacification (PCO) incidence has been followed up for a period of four years post IOL implantation to evaluate the correlation of PCO formation with surface roughness of IOLs.DesignExperimental materials study.Materials and participantsSurface characteristics of 20 different IOL models were assessed using AFM. These IOL models were made up of PMMA or HEMA or acrylic hydrophobic or acrylic hydrophilic or silicone. Retrospective analysis of PCO incidence in 3629 eyes of 2656 patients implanted with the same IOL models was performed.MethodsTopological characteristics of 20 different IOLs made up of 5 different biomaterials including (i) PMMA, (ii) HEMA, (iii) acrylic hydrophobic, (iv) acrylic hydrophilic and (v) silicone were evaluated using AFM in the tapping mode. Images were acquired with a resolution of 256 × 256 data points per scan at a scan rate of 0.5 Hz per line and a scan size of 10 × 10 μm. Rate of PCO formation in 3629 eyes of 2656 patients implanted with the five different IOL biomaterials was retrospectively analyzed.ResultsAFM images of IOL optic surfaces showed a collection of pores, grooves, ridges and surface irregularities. Surface roughness parameters of the IOL optics were significantly different on comparing lenses of different materials. Acrylic hydrophobic IOLs had minimum surface roughness while acrylic hydrophilic IOLs showed the highest surface roughness. Different IOL models of the same biomaterial showed varied topological roughness characteristics. Retrospective analyses of PCO formation rate after IOL implantation was carried out, which revealed that rate of PCO incidence, was directly proportional to the increase in surface micro-roughness of IOLs.ConclusionsAFM is a powerful technique for the topological characterization of IOLs. Acrylic hydrophobic IOLs showed minimum surface roughness properties as well as minimum PCO incidence over a period of four years post implantation. It is, therefore, tempting to consider acrylic hydrophobic IOLs over other IOL biomaterials as the ideal biocompatible material for lowering PCO incidence. These results suggest an urgent need for manufacturers to optimize the various steps involved in the fabrication of IOLs. 相似文献
218.
Rasmita Sahoo Rashmi Ranjan Mishra 《Journal of Experimental and Theoretical Physics》2012,114(5):805-809
The phonon dispersion of graphene is derived by using a simple mass spring model and considering up to the first, second, third, and fourth nearest-neighbor interactions. The results obtained from different nearest-neighbor interactions are compared and it is shown that the k 2 dependence for the out-of-plane transverse acoustic mode obtained in other sophisticated methods as well as experiment occurs only after including the fourth nearest-neighbor interaction. 相似文献
219.
Gudasi KB Shenoy RV Vadavi RS Patil SA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(3-4):598-604
Trinuclear lanthanide complexes of the formula [Ln(3)(PPDA)(NO(3))(6)(H(2)O)(2)].NO(3).2H(2)O where Ln=La(III), Pr(III), Sm(III), Nd(III), Eu(III) Gd(III) Tb(III), Dy(III) and Y(III); H(2)PPDA=N,N'-bis(2-pyridinyl)-2,6-pyridinedicarboxamide, have been isolated. The complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibility measurements and spectral (IR, NMR, UV-vis, fluorescence, FAB and EPR) and thermal studies. 相似文献
220.
The present work describes the synthesis of CdS/CdSSe glass nanocomposites and its characterization. A few glass compositions
were optimized and the optimized host glass was remelted along with different semiconductors like CdS and CdSSe at high temperature.
The CdS/CdSSe is present in amorphous state in the glass matrix. The thermal treatments have been carefully optimized to obtain
well-defined uniform crystal growth of CdS and CdSSe. The glasses with optimized conditions were fabricated and characterized
thoroughly using UV, TG/DTA and TEM. The shift in absorption edge to the longer wavelength with heat treatment implies the
increase in the crystal size. The band gap has been increased with decrease in the particle size. Crystal size of semiconductors
obtained by TEM was 2.5-5 nm for the glass showing absorption edge cut-off at 475 nm (CM-475). 相似文献