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51.
52.
A first novel synthetic utility of catalytic sodium nitrite in combination with aqueous HBr, for bromo decarboxylation of α,β-unsaturated carboxylic acid is described. α,β-Unsaturated carboxylic acid compounds successfully converted into corresponding bromo compounds. The advantages of this protocol are shorter reaction time and moderate to good yields. 相似文献
53.
54.
Parida KM Mallick S Mohapatra BK Misra VN 《Journal of colloid and interface science》2004,277(1):48-54
Physicochemical characterization of manganese-nodule leached residues was carried out by chemical analyses, XRD, TG-DTA, surface area measurement, and FTIR techniques. The material is very fine-grained (<75 microm), is cryptocrystalline to amorphous in nature, and contains mainly of delta-MnO(2), quartz (alpha-SiO(2)), and zeolite/feldspar minerals. Physically adsorbed sulfates in the leached residue are removed by repeated water washing and the washed sample shows an appreciable increase in surface area. This is indicated by the absence of 1387 and 1099 cm(-1) peaks in the IR spectrum of the washed sample. The adsorption behavior of the washed sample toward Ni(2+) was recorded as a function of time, pH, temperature, and concentrations of adsorbent and adsorbate. 相似文献
55.
Errey JC Mukhopadhyay B Kartha KP Field RA 《Chemical communications (Cambridge, England)》2004,(23):2706-2707
Enzymatic and chemo-enzymatic approaches provide straightforward access to uridine diphospho sugars irrespective of the relative and absolute configuration of the sugar, its ring size and substitution pattern. 相似文献
56.
The best possible constant An in an inequality of Markov type
, where ·[0, ∞) denotes the sup-norm on the half real line [0, ∞) and pn is an arbitrary polynomial of degree at most n, is determined in terms of the weighted Chebyshev polynomials associated with the Laguerre weight e−x on [0, ∞). 相似文献
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57.
Das B 《Chaos (Woodbury, N.Y.)》2001,11(3):632-640
This paper identifies yet another field of research, the discipline of human computer interaction, where the concept of self-similar fluctuations can play a vital role. A concept of interaction between computation and cognition is developed that is friendly toward the cognitive process. It is argued that friendly interactions must have a memory and be antipersistent. To cast this in a mathematical form, fluctuations in the interactions recorded over a period of time are studied, and it is shown that these fluctuations must necessarily be self-similar with the value of the self-similarity parameter confined to the interval (0, 1/2), for the interaction to be friendly. A statistical measure of complexity, of the interaction process, is also formulated as a function of the self-similarity parameter. Finally the question is raised as how to build a friendly software and a possible evolutionary process through which friendly softwares may emerge is indicated. (c) 2001 American Institute of Physics. 相似文献
58.
We construct the parafermionic (of orderq) representation of the Kac-Moody and Virasoro algebra and compare it with a constrained fermionic system. We find that the central charge of the Virasoro algebra of the constrained fermionic system depends on the regularization scheme. Using the path integral method, we demonstrate this dependence for theq=2 case and find that it can have the same central charge as the free parafermionic theory or the non-linear sigma model depending on the regularization scheme. We point out some ambiguity in the quantization of the constrained system in Hamiltonian formulation. 相似文献
59.
We present here a ‘similar’ solution for the nano boundary layer with nonlinear Navier boundary condition. Three types of flows are considered: (i) the flow past a wedge; (ii) the flow in a convergent channel; (iii) the flow driven by an exponentially-varying outer flows. The resulting differential equations are solved by the homotopy analysis method. Different from the perturbation methods, the present method is independent of small physical parameters so that it is applicable for not only weak but also strong nonlinear flow phenomena. Numerical results are compared with the available exact results to demonstrate the validity of the present solution. The effects of the slip length ?, the index parameters n and m on the velocity profile and the tangential stress are investigated and discussed. 相似文献
60.
Sensitivity analysis for cocoercively monotone variational inclusions and (A,η)-maximal monotonicity
Sensitivity analysis for cocoercively monotone variational inclusions based on the generalized resolvent operator technique is discussed. The notion of the cocoercive monotonicity unifies most of the existing notions, such as cocoercivity, strong monotonicity, relaxed monotonicity, relaxed cocoercivity, and others. As a result, the obtained results are general in nature. 相似文献