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排序方式: 共有146条查询结果,搜索用时 46 毫秒
91.
C. Blondel C. Delsart F. Dulieu C. Valli 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,5(2):207-216
Photodetachment of ions is performed in the presence of a static electric field. A high spatial resolution electron detector is used to map
out the ejected electron's wave function. Propagation over half a metre does not alter the stationary structure the electron
wave possesses in the direction orthogonal to the detachment motion. Nodes and antinodes of electron current density are observed,
that can be interpreted as direct imaging of the internal atomic wave function. Because detachment of a negative ion can be
represented accurately in the free-electron approximation, the obtained images can also be viewed as direct experimental representations
of the Green function of the uniform acceleration problem. Agreement of the measured distributions with the exact expression
of this wave-function appears quite satisfactory.
Received: 5 June 1998 / Accepted: 16 October 1998 相似文献
92.
Dr. Simona Bettini Dr. Rosanna Pagano Dr. Paola Semeraro Michela Ottolini Luca Salvatore Fabio Marzo Prof. Nicola Lovergine Dr. Gabriele Giancane Prof. Ludovico Valli 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(62):14123-14132
Many strategies have been adopted to improve the photoinduced features of zinc oxide nanostructures for different application fields. In this work, zinc oxide has been synthesised and decorated by plasmonic metal nanoparticles to enhance its photocatalytic activity in the visible range. Furthermore, an insulating layer of SiO2 has been grown between the surface of zinc oxide nanoflakes and silver nanoparticles. A synthetic procedure that allows the accurate modulation of the insulating layer thickness in the range 5–40 nm has been developed. Evidences highlight the crucial role of the SiO2 layer in dramatically increasing photocatalytic water oxidation promoted by the nanostructure under both UV and visible illumination. An ideal thickness value of about 10 nm has been demonstrated to guarantee the plasmon-induced resonance energy-transfer process and to quench the Förster resonance energy-transfer mechanism; thus, optimising the local surface plasmon resonance effect and water oxidation properties. 相似文献
93.
S. Anuradha Jabasingh C. Valli Nachiyar 《Journal of Thermal Analysis and Calorimetry》2012,109(1):193-202
The present study deals with the immobilization of Aspergillus nidulans SU04 cellulase onto modified activated carbon (MAC). The effect of contact time, cellulase concentration, MAC dosage, and temperature for maximum immobilization percentage and immobilization capacity is investigated. The equilibrium nature of immobilization is described by Langmuir and Freundlich isotherms. The kinetic data were tested using the pseudo first order. The activation energy of immobilization was evaluated to be 11.78?J?mol?1. Results of the thermodynamic investigation indicate the spontaneity (?G <0), slightly endothermic (?H >0), and irreversible (?S >0) nature of the sorption process. Entropy and enthalpy were found to be 41.32 J?mol?1?mg?1 and 10.99?kJ?mol?1, respectively. The Gibbs free energy was found to be ?22.79?kJ?mol?1. At 80?rpm, 323?K, 2?h, 5?mg of MAC, immobilization capacity was 4.935?mg cellulase per mg of MAC from an initial cellulase concentration of 16?mg?ml?1 with retention of 70% of native cellulase activity up to 10 cycles of batch hydrolysis experiments. The diffusion studies that were carried out revealed the reaction rate as ??mol?min?1. At optimized conditions, immobilized cellulase had a higher Michaelis?CMenten constant, K m of 1.52?mmol and a lower reaction rate, V max of 42.2???mol?min?1, compared with the free cellulase, the K m and V max values of which were 0.52?mmol and 18.9???mol?min?1, respectively, indicating the affinity of cellulase for MAC matrix. 相似文献
94.
Mathan Kumar Shanmugaiah Kesavan Mokkandi Palsamy Ravi Lokesh Indra Gandhi N. Liviu Mitu Rajesh Jegathalaprathaban Rajagopal Gurusamy 《应用有机金属化学》2019,33(3)
Among the bio‐metals, copper derivatives of O, N, S donor salicylaldehyde thiosemicarbazones have been obtained large interest due to their potential biological applications. Multisubstituted thiosemicarbazone ligand HL derived, new ternary Cu (II) complexes of [Cu(L)(bpy)] ( 1 ) and [Cu(L)(phen)] ( 2 ) (where, bpy is 2,2′‐bipyridine and phen is 1,10‐phenanthroline) have been synthesized and characterized using different physico‐chemical techniques. Complexes 1 and 2 are structurally characterized by single crystal X‐ray diffraction analysis, which reveals the trigonal bipyramidal distorted square based pyramid geometry of both the complexes 1 and 2 with ONS‐donor thiosemicarbazone bonded at the upper plane. The ground state electronic structures of complexes 1 and 2 have been investigated by using DFT/B3LYP theoretical evaluation with 6‐31G (d,p) and LANL2DZ basis set. The affinity towards DNA and human serum albumin has been evaluated using computational docking analysis and complex 2 exposes significant binding ability towards DNA and human serum albumin, because of its immense hydrophobicity. Consequently, complex 2 have higher antimicrobial in addition to the cytotoxic activity than complex 1 and free ligand HL under visible light. Along with, their apoptosis pathway of cytotoxicity has been evaluated by fluorescent microscopic analysis using acridine orange/ethidium bromide (AO/EB) stains. From these preliminary investigations, we believe that complex 2 can play a role as a more robust pharmacological agent. 相似文献
95.
Zanoni G Valli M Bendjeddou L Porta A Bruno P Vidari G 《The Journal of organic chemistry》2010,75(23):8311-8314
Endogenous nitro-fatty acids, acting as partial agonist of PPARγ, are able to lower the insulin and glucose levels without the side effects associated with common antidiabetic drugs. (E)-12-Nitrooctadec-12-enoic acid, a potent activator of this peroxisome receptor, was synthesized in a very efficient sequence via a Henry-retro-Claisen ring fragmentation, followed by a novel enzymatic cleavage of methyl esters. The latter method was then applied in the last step of the synthesis of a few labile natural products, such as prostaglandins, isoprostanes, and phytoprostanes. 相似文献
96.
Alberto Valli 《Applied Mathematics Letters》2012,25(10):1410-1414
The aim of this note is to give a simple and direct proof of the existence and uniqueness of the solution to an electrostatics-like problem when the source (namely, the applied current density) is a current dipole. The result is obtained by using the classical duality method. 相似文献
97.
New anthracene based Schiff base ligands appended Cu(II) complexes: Theoretical study,DNA binding and cleavage activities
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Ammavasai Gubendran Gujuluva Gangatharan Vinoth Kumar Mookkandi Palsamy Kesavan Gurusamy Rajagopal Periakaruppan Athappan Jegathalaprathaban Rajesh 《应用有机金属化学》2018,32(3)
New anthracene based Schiff base ligands L 1 and H( L 2 ), their Cu(II) complexes [Cu( L 1 )Cl2] ( 1 ) and [Cu( L 2 )Cl] ( 2 ) , (where L 1 = N1,N2‐bis(anthracene‐9‐methylene)benzene‐1,2‐diamine, L 2 = (2Z,4E)‐4‐(2‐(anthracen‐9‐ylmethyleneamino)phenylimino)pent‐2‐en‐2‐ol) have been prepared and characterized by elemental analysis, NMR, FAB‐mass, EPR, FT‐IR, UV–Vis and cyclic voltammetry. The electronic structures and geometrical parameters of complexes 1 and 2 were analyzed by the theoretical B3LYP/DFT method. The interaction of these complexes 1 and 2 with CT‐DNA has been explored by using absorption, cyclic voltammetric and CD spectral studies. From the electronic absorption spectral studies, it was found that the DNA binding constants of complexes 1 and 2 are 8.7 × 103 and 7.0 × 104 M?1, respectively. From electrochemical studies, the ratio of DNA binding constants K+/K2+ for 2 has been estimated to be >1. The high binding constant values, K+/K2+ ratios more than unity and positive shift of voltammetric E1/2 value on titration with DNA for complex 2 suggest that they bind more avidly with DNA than complex 1 . The inability to affect the conformational changes of DNA in the CD spectrum is the definite evidences of electrostatic binding by the complex 1 . It can be assumed that it is the bulky anthracene unit which sterically inhibits these complexes 1 and 2 from intercalation and thereby remains in the groove or electrostatic. The complex 2 hardly cleaves supercoiled pUC18 plasmid DNA in the presence of hydrogen peroxide. The results suggest that complex 2 bind to DNA through minor groove binding. 相似文献
98.
Vera Bernardoni Eleonora Cuccia Giulia Calzolai Massimo Chiari Franco Lucarelli Dario Massabò Silvia Nava Paolo Prati Gianluigi Valli Roberta Vecchi 《X射线光谱测定》2011,40(2):79-87
The knowledge of size‐segregated elemental concentrations in atmospheric particulate matter (PM) gives a useful contribution to the complete chemical characterisation; this information can be obtained by sampling with multi‐stage cascade impactors. In this work, samples were collected using a low‐pressure 12‐stage Small Deposit Impactor and a 13‐stage rotating Micro Orifice Uniform Deposit Impactor?. Both impactors collect the aerosol in an inhomogeneous geometry, which needs a special set‐up for X‐ray analysis. This work aims at setting up an energy dispersive X‐ray fluorescence (ED‐XRF) spectrometer to analyse quantitatively size‐segregated samples obtained by these impactors. The analysis of cascade impactor samples by ED‐XRF is not customary; therefore, as additional consistency test some samples were analysed also by particle‐induced X‐ray emission (PIXE), which is more frequently applied to size‐segregated samples characterised by small PM quantities. A very good agreement between ED‐XRF and PIXE results was obtained for all the detected elements in samples collected with both impactors. The good inter‐comparability proves that our methodology is reliable for analysing size‐segregated samples by ED‐XRF technique. The advantage of this approach is that ED‐XRF is cheaper, easier to use, and more widespread than PIXE, thus promoting an intensive use of multi‐stage impactors. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
99.
100.
Gurusamy Ravindran Shanmugam Muthusubramanian Sanguvan Selvaraj Subbu Perumal 《Journal of heterocyclic chemistry》2007,44(1):133-136