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181.
S Mogurampelly S Panigrahi D Bhattacharyya AK Sood PK Maiti 《The Journal of chemical physics》2012,137(5):054903
Using all atom molecular dynamics simulations, we report spontaneous unzipping and strong binding of small interfering RNA (siRNA) on graphene. Our dispersion corrected density functional theory based calculations suggest that nucleosides of RNA have stronger attractive interactions with graphene as compared to DNA residues. These stronger interactions force the double stranded siRNA to spontaneously unzip and bind to the graphene surface. Unzipping always nucleates at one end of the siRNA and propagates to the other end after few base-pairs get unzipped. While both the ends get unzipped, the middle part remains in double stranded form because of torsional constraint. Unzipping probability distributions fitted to single exponential function give unzipping time (τ) of the order of few nanoseconds which decrease exponentially with temperature. From the temperature variation of unzipping time we estimate the energy barrier to unzipping. 相似文献
182.
We demonstrate that one can exhaustively determine the n‐bound eigenstates of a Hamiltonian H by constructing a sequence of supersymmetric (SUSY) partner Hamiltonians and invoking a time‐dependent quantum adiabatic switching algorithm for passage from the ground state of one to the other. The ground states of the initial pair H(0) and H(1) are constructed by solving the Riccati equation for the superpotential ?(0) for H(0) and adiabatically switching from the ground state Ψ of H(0) to the ground state Ψ of H(1). The charge operator Q is then used to recover the first excited state Ψ of H(0). The procedure is repeated for the ground states of SUSY pairs H(n + 1) and H(n + 2), and appropriate charge operators lead to the excited states Ψ of H(0) with , thereby exhausting the full eigenspectrum of H(0). The workability of the proposed method is shown with several well‐known examples. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011 相似文献
183.
Tam NM Ngan VT de Haeck J Bhattacharyya S Le HT Janssens E Lievens P Nguyen MT 《The Journal of chemical physics》2012,136(2):024301
The geometric structures of neutral and cationic Si(n)Li(m)(0/+) clusters with n = 2-11 and m = 1, 2 are investigated using combined experimental and computational methods. The adiabatic ionization energy and vertical ionization energy (VIE) of Si(n)Li(m) clusters are determined using quantum chemical methods (B3LYP/6-311+G(d), G3B3, and CCSD(T)/aug-cc-pVxZ with x = D,T), whereas experimental values are derived from threshold photoionization experiments in the 4.68-6.24 eV range. Among the investigated cluster sizes, only Si(6)Li(2), Si(7)Li, Si(10)Li, and Si(11)Li have ionization thresholds below 6.24 eV and could be measured accurately. The ionization threshold and VIE obtained from the experimental photoionization efficiency curves agree well with the computed values. The growth mechanism of the lithium doped silicon clusters follows some simple rules: (1) neutral singly doped Si(n)Li clusters favor the Li atom addition on an edge or a face of the structure of the corresponding Si(n)(-) anion, while the cationic Si(n)Li(+) binds with one Si atom of the bare Si(n) cluster or adds on one of its edges, and (2) for doubly doped Si(n)Li(2)(0/+) clusters, the neutrals have the shape of the Si(n+1) counterparts with an additional Li atom added on an edge or a face of it, while the cations have both Li atoms added on edges or faces of the Si(n)(-) clusters. 相似文献
184.
Swati Mukhopadhyay Krishnendu Bhattacharyya 《Journal of the Egyptian Mathematical Society》2012,20(3):229-234
An analysis is presented for unsteady two-dimensional flow of a Maxwell fluid over a stretching surface in presence of a first order constructive/destructive chemical reaction. Using suitable transformations, the governing partial differential equations are converted to ordinary one and are then solved numerically by shooting method. The flow fields and mass transfer are significantly influenced by the governing parameters. Fluid velocity initially decreases with increasing unsteadiness parameter and concentration decreases significantly due to unsteadiness. The effect of increasing values of the Maxwell parameter is to suppress the velocity field. But the concentration is enhanced with increasing Maxwell parameter. 相似文献
185.
Kinkini Bhattacharyya Tanusree Kar Pradeep Kumar Dutta Basudeb Achari Gabriele Bocelli Lara Righi 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(2):e60-e61
The title compound, C34H52O4, consists of five six‐membered rings. Barring the two rings, with double bonds, all other rings are in chair conformations. Mean‐plane and ring‐puckering calculations indicate these two rings to be in distorted‐chair conformations, with distortion towards the boat conformation. There are no strong hydrogen bonds and the structure is stabilized by van der Waals interactions only. The structure is compared with those reported for other triterpenes. 相似文献
186.
E. R. E. Müller H. Phillips Chemikerausschuss des U. S. Stahlverbandes Haripada Bhattacharyya L. T. Bowser Fr. Ibbotson H. Brearley R. J. Wysor F. W. Hinrichsen Th. Dieckmann G. Misson R. Schröder D. Chouchak Ph. A. Kober und Grete Egerer 《Fresenius' Journal of Analytical Chemistry》1917,56(8):396-405
Ohne Zusammenfassung 相似文献
187.
A new method based on the penalty-function way of satisfying equality constraints is proposed for the determination of constrained
pure state one-electron density matrices for closed-shell many-electron systems. The algorithm suggested can handle many constraints
simultaneously. Certain interesting features of the proposed algorithm are discussed with numerical examples. 相似文献
188.
189.
S. Bhattacharyya 《Il Nuovo Cimento C》1988,11(4):429-436
Summary We present here an analysis of the nature of the problematical π/p ratio on the basis of the modified (or revised) closed
galaxy model (MCGM) and the two forms of scaling violation effect one of which is called the model with moderate violation
of Feynman scaling and the other called model with stronger violation of Feynman scaling at very high energies. Using both
the JACEE and the non-JACEE forms of primary nucleon spectra, the theoretical values obtained with these two types of scaling
violation forms and the modified closed galaxy model are always greater than experimental measurements, especially at low
energies. Attempts to account for these discrepancies have also been made.
Riassunto Si presenta qui un'analisi della natura del rapporto problematico π/p sulla base del modello della galassia chiusa modificato (o rivisto) (MCGM) e sulle due forme dell'effetto di violazione di scala di cui uno è chiamato il modello con violazione moderata della scala di Feynman e l'altro con violazione più forte della scala di Feynman ad energie molto alte. Usando sia le forme di JACEE e non degli spettri dei nucleoni primari, i valori teorici ottenuti con questi due tipi di forme di violazione di scala e il modello della galassia chiusa modificato sono sempre maggiori delle misure sperimentali, specialmente ad energie basse. Si sono anche effettuati tentativi per spiegare queste discordanze.相似文献
190.
The Mössbauer spectra of powdered Eu(OH)3 were recorded between 300 and 4.2 K, with 151SmF3 as source. The spectra showed one single absorption line having definite width but without any fine structure. The lattice Sternheimer factor γ∞ of 151Eu in Eu(OH)3 was estimated with the help of these spectra as well as by using the values of some physical parameters obtained from spectral and magnetic susceptibility measurements on pure single crystal of Eu(OH)3, The value of lattice Sternheimer factor (= -87) thus evaluated is slightly larger than that value ( = - 80) for 154Eu in ethylsulphate host. This result is consistent with the γ∞ values of other rare-earth ions and also with the results obtained from magnetic and optical experiments on Eu(OH)3. 相似文献