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61.
Shreya Mahato Nishith Meheta Muddukrishnaiah Kotakonda Mayank Joshi Prasanta Ghosh Madhusudan Shit Angshuman Roy Choudhury Bhaskar Biswas 《应用有机金属化学》2020,34(11):e5935
In pursuit of the significant contribution of copper ion in different biological processes, this research work describes the synthesis, X-ray structure, Hirshfeld surface analysis, oxidative dimerization of 2-aminophenol and antibacterial activity of a newly designed copper (II)-Schiff base complex, [Cu( L )2] (1), [Schiff base (H L ) = 2-(2-methoxybenzylideneamino)phenol]. X- ray structural analysis of 1 reveals that the Cu (II) complex crystallizes in a cubic crystal system with Ia-3d space group. The Cu (II) centre adopts an unprecedented tetragonal bipyramidal geometry in its crystalline phase. The Schiff base behaves as a tridentate chelator and forms an innermetallic chelate of first order with Cu (II) ion. The copper (II) complex has been tested in the bio-mimics of phenaxozinone synthase activity in acetonitrile and exhibits good catalytic activity as evident from high turnover number, 536.4 h−1. Electrochemical analysis exhibits the appearance of two additional peaks at −0.15 and 0.46 V for Cu (II) complex in presence of 2-AP and suggests the development of AP−/AP•− and AP•−/IQ redox couples in solution, respectively. The presence of iminobenzosemiquinone radical at g = 2.057 in the reaction mixture was confirmed by electron paramagnetic resonance and may be considered the driving force for the oxidative dimerisation of 2-AP. The existence of a peak at m/z 624.81 for Cu (II) complex in presence of 2-AP in electrospray ionization mass spectrum ensures that the catalytic oxidation proceeds through enzyme-substrate adduct formation. The copper (II) complex exhibits potential antibacterial properties against few pathogenic bacterial species like Staphylococcus aureus, Enterococcus and Klebsiella pneumonia and scanning electron microscope studies consolidates that destruction of bacterial cell membrane accounts on the development of antibacterial activity. 相似文献
62.
Biswas Kuheli Shreshtha Mayank Surendran Anudeep Ghosh Anandamohan 《The European physical journal. E, Soft matter》2019,42(2):1-10
The European Physical Journal E - To theoretically understand force generation properties of actin filaments, many models consider growing filaments pushing against a movable obstacle or barrier.... 相似文献
63.
Vikash Mishra Ishan Mohanty Mayank R. Patel 《International Journal of Polymer Analysis and Characterization》2015,20(6):504-513
A series of novel waterborne UV-curable polyurethane dispersions were synthesized from castor oil, IPDI, DMPA, and HEMA by the acetone process. The prepared UV-PUD was mixed with three different monomers and characterized for the parameters relevant to the study by physical, spectroscopic, and chemical methods. The effect of monomer type on the physicochemical and thermal properties of UV-PUDs revealed that the number of unsaturated groups present in the monomer had a pronounced effect on physicochemical, mechanical, and thermal properties. The combination of renewable resource and environmentally compliant technology give these UV-PUDs potential scope in coating applications. 相似文献
64.
The reaction of dehydroacetic acid with iodosobenzene in combination with Vilsmeier–Haack reagent offers a new and convenient method for C‐C bond cleavage with the formation of 3‐chloro‐4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one. 相似文献
65.
Flying onto global minima on potential energy surfaces: A swarm intelligence guided route to molecular electronic structure
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Rishabh Shukla Debmalya Ray Kanchan Sarkar Mayank Kumar Dixit Shankar Prasad Bhattacharyya 《International journal of quantum chemistry》2017,117(5)
A novel quantum‐classical recipe for locating the global minimum on the potential energy surface of a large molecule and simultaneously predicting the associated electronic charge distribution is developed by interfacing the classical particle swarm optimization with a near optimal unitary evolution scheme for the trial one electron density matrix. The unitary transformation is generated by an antihermitian matrix linked to the molecular electronic Hamiltonian at the instantaneous nuclear configurations discovered by the swarm as it flies. The algorithm is used to predict the extensive reorganization of electronic charge distribution and bond lengths in polythiophene oligomers on doping at various levels. 相似文献
66.
Mayank Goswami Xianfeng Gu Vamsi P. Pingali Gaurish Telang 《Foundations of Computational Mathematics》2017,17(2):497-526
By the Riemann mapping theorem, one can bijectively map the interior of an n-gon P to that of another n-gon Q conformally (i.e., in an angle-preserving manner). However, when this map is extended to the boundary, it need not necessarily map the vertices of P to those of Q. For many applications, it is important to find the “best” vertex-preserving mapping between two polygons, i.e., one that minimizes the maximum angle distortion (the so-called dilatation). Such maps exist, are unique, and are known as extremal quasiconformal maps or Teichmüller maps. There are many efficient ways to approximate conformal maps, and the recent breakthrough result by Bishop computes a \((1+\varepsilon )\)-approximation of the Riemann map in linear time. However, only heuristics have been studied in the case of Teichmüller maps. This paper solves the problem of finding a finite-time procedure for approximating Teichmüller maps in the continuous setting. Our construction is via an iterative procedure that is proven to converge in \(O(\text {poly}(1/\varepsilon ))\) iterations to a map whose dilatation is at most \(\varepsilon \) more than that of the Teichmüller map, for any \(\varepsilon >0\). We reduce the problem of finding an approximation algorithm for computing Teichmüller maps to two basic subroutines, namely, computing discrete (1) compositions and (2) inverses of discretely represented quasiconformal maps. Assuming finite-time solvers for these subroutines, we provide an approximation algorithm with an additive error of at most \(\varepsilon \). 相似文献
67.
Suresh Rajamanickam Mayank Saraswat Sugumar Venkataramani Bhisma K. Patel 《Chemical science》2021,12(46):15318
An intermolecular radical based distal selectivity in appended alkyl chains has been developed. The selectivity is maximum when the distal carbon is γ to the appended group and decreases by moving from γ → δ → ε positions. In –COO– linked alkyl chains, the same distal γ-selectivity is observed irrespective of its origin, either from the alkyl carboxy acid or alkyl alcohol. The appended groups include esters, N–H protected amines, phthaloyl, sulfone, sulfinimide, nitrile, phosphite, phosphate and borate esters. In borate esters, boron serves as a traceless directing group, which is hitherto unprecedented for any remote Csp3–H functionalization. The selectivity order follows the trend: 3° benzylic > 2° benzylic > 3° tertiary > α to keto > distal methylene (γ > δ > ε). Computations predicted the radical stability (thermodynamic factors) and the kinetic barriers as the factors responsible for such trends. Remarkably, this strategy eludes any designer catalysts, and the selectivity is due to the intrinsic substrate reactivity.An intermolecular amination at the distal methylene carbon has been realized in an appended alkyl chain with electron withdrawing groups. Traceless remote Csp3–H functionalization has been accomplished using borate esters. 相似文献
68.
Feldspar contaminants in quartz aliquots, either as micro-inclusions or as remnant grains (due to inadequate etching) can affect the accuracy and precision of paleodose estimates based on blue-green light stimulated luminescence (BGSL). Such contamination could also alter the shape of the BGSL stimulation curve of otherwise pure quartz. In this study, the functional relationship between the infra-red stimulated luminescence (IRSL) and BGSL of feldspars, (1) at different preheats, and (2) with IR bleaching at different stimulation temperatures and durations, is examined. The results suggest two trap populations participate in the feldspar BGSL process. These are: (1) Type (A) trap populations that can be stimulated by both the infra-red and the blue-green light at 125°C and, (2) Type (B) trap populations that respond only to blue-green-light stimulation at 125°C. However, infra-red stimulation at elevated temperature (220°C) (ETIR) permits depletions of charges in Type (A) and Type (B) to the extent that the feldspar BGSL can be reduced by up to 97% in 5 min.
These results offer prospects for (1) improved precision in paleodose estimates based on quartz; (2) BGSL dating of quartz in a polyminerallic fine grain samples; (3) age estimates based on both quartz and feldspars from the same aliquots, and (4) dating based on feldspar micro-inclusions. 相似文献
69.
Vijay K. Yadav Vijay K. Shukla Subir Das Mayank Srivastava 《Chinese Journal of Physics (Taipei)》2018,56(2):696-707
In this article, the stability analysis, chaos control and the function projective synchronization between fractional order identical satellite systems have been studied. Based on the stability theory of fractional order systems, the conditions of local stability of nonlinear three-dimensional commensurate and incommensurate fractional order systems are discussed. Feedback control method is used to control the chaos in the considered fractional order satellite system. Using the fractional calculus theory and computer simulation, it is found that the chaotic behavior exists in the fractional order satellite system and the lowest order of derivative where the chaos exits is 2.82. Adams-Bashforth-Moulton method is applied during numerical simulations and the results obtain are displayed through graphs. 相似文献
70.
Suppose that there are n jobs and n machines and it costs cij to execute job i on machine j. The assignment problem concerns the determination of a one‐to‐one assignment of jobs onto machines so as to minimize the cost of executing all the jobs. When the cij are independent and identically distributed exponentials of mean 1, Parisi [Technical Report cond‐mat/9801176, xxx LANL Archive, 1998] made the beautiful conjecture that the expected cost of the minimum assignment equals . Coppersmith and Sorkin [Random Structures Algorithms 15 ( 6 ), 113–144] generalized Parisi's conjecture to the average value of the smallest k‐assignment when there are n jobs and m machines. Building on the previous work of Sharma and Prabhakar [Proc 40th Annu Allerton Conf Communication Control and Computing, 20 , 657–666] and Nair [Proc 40th Annu Allerton Conf Communication Control and Computing, 17 , 667–673], we resolve the Parisi and Coppersmith‐Sorkin conjectures. In the process we obtain a number of combinatorial results which may be of general interest.© 2005 Wiley Periodicals, Inc. Random Struct. Alg. 2005 相似文献