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81.
Ray A Chattopadhyay S Bhattacharya S 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(5):1435-1442
The photo-physical aspects of non-covalently linked assemblies of a series of fullerenes, namely, C60, C70, tert-butyl-(1,2-methanofullerene)-61-carboxylate (1) and [6,6]-phenyl C70 butyric acid methyl ester (2) with a designed zinc phthalocyanine (ZnPc), viz., zinc-1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine (3) in toluene medium are studied employing absorption spectrophotometric, steady state and time resolved fluorescence spectroscopic measurements. Of central interest in these investigations is the preferential binding of various fullerenes with ZnPc in toluene. The ground state interaction between fullerenes and 3 is first evidenced from UV-Vis measurements. Steady state fluorescence experiment reveals efficient quenching of the excited singlet state of 3 in presence of both underivatized and derivatized fullerenes. K values for the complexes of C60, C70, 1 and 2 with 3 are determined to be 6500, 22,230, 47,800 and 54,770 dm3 mol(-1), respectively. The magnitude of K suggests that 3 preferentially binds C70 and derivatized C70 in comparison to C60 and 1. Time resolved emission measurements establish that C(70)-3 and 2-3 complexes are stabilized much more in comparison to C(60)-3 and 1-3 systems in terms of charge separation process. Semi empirical calculations employing third parametric method substantiate the strong binding of C70 and its derivative with 3 in terms of heat of formation values of the respective complexes, and at the same time, determine the orientation of bound guest (here fullerenes) with the molecular plane of 3. 相似文献
82.
83.
Nidhi Joshi Anindita Mukhopadhyay Sujit Basak Goutam De Krishnananda Chattopadhyay 《Particle & Particle Systems Characterization》2013,30(8):683-694
The presence of magnetic nanoparticles (NPs) in physiological systems induces toxicity through its effects on mitochondrial function and reactive oxygen species (ROS) imbalance. Magnetic NP induced cytotoxicity has been elaborately evaluated for impending threats, however, a detailed investigation is lacking. It is shown that the interaction of Fe3O4 NPs with cytochrome c can lead to different events based on the NPs to protein ratio, the solution conditions, and the type of surface protection. At low NPs concentration, rapid binding and subsequent electron transfer are the preferred events while at higher concentration slow oxidative modification of the protein is initiated. The slow event of protein modification yields conformational disorientation, loss of stability, and formation of amyloid‐like structures with cytochrome c. The possibility that the NP induced oxidative stress and age can work in concert to compromise different aspects of cellular quality control processes is discussed. Suitable surface modifications of the NPs inhibit their direct binding to the protein molecules and minimize NP induced toxicity. 相似文献
84.
A stochastic manpower planning model under varying class sizes 总被引:1,自引:0,他引:1
Solution related to different types of manpower planning problems arising in different industries and organizations are very
much helpful for proper planning and implementation of different objectives. Previously those type of problems are mostly
solved under the deterministic set up. Gradually several scientists have developed different types of stochastic models appropriate
for solving such types of problems. The present study is an attempt to develop a stochastic manpower planning model under
the set up where the classes are of varying sizes and promotion occurs only on the basis of seniority.
The work of second author was supported by a research fellowship from Council of Scientific and Industrial Research (Sanction
No. 9/28(611)/2003-EMR-I), India. 相似文献
85.
P. Chattopadhyay 《Applied Surface Science》2006,252(12):4055-4063
An energy distribution of interface states has been considered to study the electrical characteristics of an anisotype semiconductor heterojunction. Various electrical quantities such as the surface potential, current, conductance and ideality factor of the device have been studied. The current-voltage and conductance-voltage characteristics are found largely sensitive to the parameters controlling the distribution profile of interface states. A new expression for the ideality factor of the device has been derived, which predicts appreciable voltage dependence due to the distributive nature of the interface states. It has been found that the experimental I-V data of p-InP/n-CdS heterojunction reported by earlier workers can be satisfactorily explained with the help of the present model if the effect of shunt resistance of the device is included in the evaluation scheme. 相似文献
86.
In this paper, we propose a scheme for the generation of low phase noise tunable mm-wave signal by beating two lightwaves in a photodiode. These two lightwaves are made phase coherent by an optoelectronic phase locked loop.Calculated mm-wave power at a frequency of 60 GHz is found to be -4 dBm. 相似文献
87.
Dipankar Mishra Subhendu Naskar Shyamal K. Chattopadhyay Milan Maji Parbati Sengupta Rupam Dinda Saktiprasad Ghosh Thomas C. W. Mak 《Transition Metal Chemistry》2005,30(3):352-356
The synthesis, crystal structure, redox and spectroscopic properties of trans-[Ru(bbpH2)(PPh3)2Cl]Cl are reported. In the crystalline solvate trans-[Ru(bbpH2)(PPh3)2cCl]Cl CHCl3 H2O, the molecular components are connected by strong intermolecular hydrogen bonding to form an infinite double column. 相似文献
88.
A detailed numerical analysis of the boundary value problem resulting from the most general Skyrme type lagrangian containing
up to quartic terms in field gradients is presented. The additional parameters in the lagrangian can be related to pion-pion
scattering lengths. It is found that solutions to the boundary value problem does not exist for all values of the parameters
and in particular, for the values predicted from pion-pion scattering data. Physical quantities of the nucleon are calculated
for the highest possible values of the parameters admitting a solution and are compared with the corresponding values for
the Skyrme model and experimental values. 相似文献
89.
Received: 15 August 1997/Accepted: 13 November 1997 相似文献
90.