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71.
Santanu K.?MaitiEmail author 《The European Physical Journal B - Condensed Matter and Complex Systems》2013,86(6):296
We investigate the conformation-dependent electron transfer in a biphenyl molecule within a simple tight-binding framework. The overall junction current and circular currents in two benzene rings driven by applied bias voltage are calculated by using Green’s function formalism. Our analysis may provide the possibilities of using organic molecules with loop substructures to design molecular spintronic devices, indicating the emergence of molecular spintronics. 相似文献
72.
In the context of designing an efficient thermoelectric energy-conversion device at nanoscale level, we suggest several important tuning parameters to enhance the performance of thermoelectric converters. We consider a simple molecular junction, which is always helpful to understand the basic mechanisms in a deeper way, where a benzene molecule is coupled to two external baths having unequal temperatures. The key component responsible for achieving better performance is associated with the asymmetric nature of transmission function, and in the present work, we show that it can be implemented in different ways by regulating the physical parameters involving the system. Employing a tight-binding framework we calculate electrical and thermal conductances, thermopower, and figure of merit (FOM) by using Landauer integrals, and thoroughly examine the critical roles played by molecule-to-lead (ML) interface geometry, magnetic field, chemical substituent group, ML coupling, and the direct coupling between the two leads. Our results show that a reasonably large FOM (≫1) can be obtained and lead to a possibility of regulating the efficiency by selectively tuning the physical parameters. We believe that the present analysis will enhance the understanding of designing efficient thermoelectric devices, and can be verified in a laboratory. 相似文献
73.
P.D. Shidling N. Madhavan V.S. Ramamurthy S. Nath N.M. Badiger Santanu Pal A.K. Sinha A. Jhingan S. Muralithar P. Sugathan S. Kailas B.R. Behera R. Singh K.M. Varier M.C. Radhakrishna 《Physics letters. [Part B]》2008
Evaporation residue (ER) cross sections and gamma multiplicity distributions have been measured for 16O + 184W and 19F + 181Ta systems in the excitation energy range of 50–90 MeV, leading to the same compound nucleus 200Pb∗. Comparison of experimental results of both the systems shows that ER cross sections and moments of gamma multiplicity distribution of 16O + 184W system are significantly higher than those of 19F + 181Ta system at higher excitation energies. Present measurements directly shows the experimental signature of entrance channel effect even with the systems which are not very different with respect to their entrance channel mass asymmetry. It is further demonstrated that the reduction in the ER cross section and moments of spin distribution for 19F + 181Ta system is mainly due to the suppression of fusion of higher l values. 相似文献
74.
Subrata Hazra Somenath Mahato Kanak Kanti Das Dr. Santanu Panda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(44):e202200556
Heteroaryl boronic acids and esters are extremely important and valuable intermediates because of their wide application in the synthesis of marketed drugs and bioactive compounds. Over the last couple of decades, the construction of highly important heteroaryl carbon-boron bonds has created huge attention. The transition-metal-free protocols are more green, less sensitive to air and moisture, and also economically advantageous over the transition-metal-based protocols. The transition-metal-free C−H borylation of heteroarenes and C−X (X=halogen) borylation of heteroaryl halides represents an excellent approach for their synthesis. Also, various cyclization and alkyne activation protocols have been recently established for their synthesis. The goal of this review article is to summarize the existing literature and the current state of the art for transition-metal-free synthesis of heteroaryl boronic acid and esters. 相似文献
75.
Designs, Codes and Cryptography - We propose a deterministic algorithm to recover some state bits of any FSR-based stream cipher knowing some keystream bits by fixing some state bits. This... 相似文献
76.
77.
Surbhi Grewal Pravesh Kumar Dr. Saonli Roy Dr. Indu Bala Dr. Chitranjan Sah Dr. Santanu Kumar Pal Dr. Sugumar Venkataramani 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(19):e202104602
Two tripodal C3-symmetric photoswitchable molecular systems T1 and T2 are reported that have extended conjugation at external and internal positions using an acryl group. The influence of the extended π-bonds in their absorption properties, thermal relaxation of the photoisomers and their propensities in forming supramolecular self-assemblies have been explored through spectroscopy, and microscopic studies. In particular, the investigations on the self-assembly have been carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), polarized optical microscopy (POM), X-ray diffraction studies (XRD) and atomic force microscopy (AFM). Remarkably, the position of the acryl group influences the behaviour of the two target molecules in supramolecular assembly, and also in the formation of photoresponsive organic hydrogels or microcrystals. 相似文献
78.
Paolo Ravarino Dr. Santanu Panja Simona Bianco Dr. Todor Koev Dr. Matthew Wallace Prof. Dave J. Adams 《Angewandte Chemie (International ed. in English)》2023,62(4):e202215813
We use a pH-driven annealing process to convert between co-assembled and self-sorted networks in multicomponent gels. The initially formed gels at low pH are co-assembled, with the two components coexisting within the same self-assembled structures. We use an enzymatic approach to increase the pH, resulting in a gel-to-sol transition, followed by a hydrolysis to lower the pH once again. As the pH decreases, a self-sorted network is formed by a two-stage gelation process determined by the pKa of each component. This approach can be expanded to layered systems to generate many varied systems by changing composition and rates of pH change, adapting their microstructure and so allowing access to a far greater range of morphologies and complexity than can be achieved in single component systems. 相似文献
79.
Ray S Sedev R Priest C Ralston J 《Langmuir : the ACS journal of surfaces and colloids》2008,24(22):13007-13012
The velocity dependence of the dynamic contact angle for a glycerol-water mixture wetting two different chemically heterogeneous surfaces (mixed thiols on gold and partially methylated titania, 16 samples in all) was studied. The molecular kinetic theory (MKT) of wetting was used to interpret the dynamic contact angle data. The equilibrium displacement frequency ( K 0) was predominantly determined by the viscous contribution from the bulk liquid, with a minor contribution from the surface. The mean distance between surface sites (lambda) decreased with increasing work of adhesion. The contact line friction coefficient zeta 0 was found to vary exponentially with the work of adhesion, enabling the unit flow volume of the liquid to be obtained. 相似文献
80.
We describe the new nanostructured Pt/Ge/Se materials prepared from the molecular units [Ge2Se6](4-) and [GeSe4](4-) and linking Pt(2+) ions in the presence of surfactant micelles. X-ray diffraction coupled with transmission electron microscopy images reveals hexagonal pore symmetry. The solvent dependence and solution speciation of these building blocks were investigated by means of multinuclear NMR spectroscopy and by fast atom bombardment (FAB) mass spectroscopy and it is shown that rapid exchange equilibrium is reached between species like [Ge4Se10](4-), [Ge2Se6](4-), and [GeSe4](4-) in both water and formamide. This results in multiple Ge/Se anions being incorporated in the mesostructured materials which is supported by Raman and IR spectroscopic data. It is likely that the presence of multiple building units both in water and formamide solutions favors the assembly of mesostructured metal chalcogenides with good pore order. Systematic variation of both surfactant headgroup and chain length modulates the optoelectronic properties of the mesostructures. The Pt/Ge/Se materials show sharp band gap transitions in the range of 1.24-1.97 eV. Finally, the materials exhibit reversible ion-exchange properties and a marked inorganic framework flexibility that enables a contraction-expansion process in response to the exchange. The Pt/Ge/Se framework possesses a very high surface area as estimated by small-angle X-ray scattering techniques. 相似文献