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61.
We present a necessary and sufficient condition for existence of a contractible, non-separating and non-contractible separating Hamiltonian cycle in the edge graph of polyhedral maps on surfaces. We also present algorithms to construct such cycles whenever it exists where one of them is linear time and another is exponential time algorithm. 相似文献
62.
2-Arylazo-5,5,10,10,15,15,20,20-octamethylcalix[4]pyrroles (azo-OMCPs) have been synthesised by the reaction of calix[4]pyrrole with aryldiazonium chloride in 15–45% yields. The solution-state binding studies of the synthesised hosts were investigated by absorption spectroscopy and 1H NMR in DMSO and CDCl3, respectively. These receptors, appended with electron-donating and electron-withdrawing groups, displayed enhanced affinity and selectivity for fluoride anion. Well-defined colour change in the visible region of the spectrum was observed upon addition of fluoride ion in DMSO solution of azo-OMCPs. Detailed NMR studies in CDCl3 revealed that azo-OMCPs with nitro and chloro groups have higher binding affinity for fluoride ion. 相似文献
63.
R. Pankajavalli Ashish Jain Akanksha Sharma S. Anthonysamy V. Ganesan 《Journal of Thermal Analysis and Calorimetry》2013,112(1):83-93
The standard Gibbs energy of formation of M2TeO6 and M6TeO12 (where M = Sc, Y), was determined from its vapor pressure measurements by employing thermogravimetry-based transpiration technique. This technique was validated by measuring the vapor pressure of well-studied substances such as TeO2(s) and CdCl2(s). The temperature dependence of the vapor pressure of TeO2(g) over the mixtures M6TeO12 + M2O3 (where M = Sc, Y), generated by the incongruent vaporization reaction, M6TeO12(s) → 3M2O3(s) + TeO2(g) + ½O2(g) were measured in the temperature range 1,413–1,473 K and 1,623–1,743 K for Sc6TeO12(s) and Y6TeO12(s), respectively. Similarly, the vapor pressure of TeO2(g) over the mixtures M2TeO6(s) + M6TeO12(s) generated by the vaporization reaction, 3M2TeO6(s) → M6TeO12(s) + 2TeO2(g) + O2(g) was measured in the temperature range (1,223–1,293 K) and (1,333–1,423 K) for Sc2TeO6(s) and Y2TeO6(s), respectively. From the vapor pressure measurements, the standard Gibbs energy of formation of M6TeO12 and M2TeO6 were derived. 相似文献
64.
Amrita Jain S. K. Tripathi Ashish Gupta Manju Kumari 《Journal of Solid State Electrochemistry》2013,17(3):713-726
The present investigation deals with electrochemical double layer capacitors (EDLCs) made up of ionic liquid (IL)-based gel polymer electrolytes with chemically treated activated charcoal electrodes. The gel polymer electrolyte comprising of poly(vinylidine fluoride-co-hexafluropropylene) (PVdF-HFP)–1-ethyl-2,3-dimethyl-imidazolium-tetrafluroborate [EDiMIM][BF4]–propylene carbonate (PC)–magnesium perchlorate (Mg(ClO4)2) exhibits the highest ionic conductivity of ~8.4?×?10?3?S?cm?1 at room temperature (~20 °C), showing good mechanical and dimensional stability, suitable for their application in EDLCs. Activation of charcoal was done by impregnation method using potassium hydroxide (KOH) as activating agent. Brunauer–Emmett–Teller (BET) studies reveal that the effective surface area of treated activated charcoal powder (1,515 m2?g?1) increases by more than double-fold compared to the untreated one (721 m2?g?1). Performance of EDLCs has been tested using cyclic voltammetry, impedance spectroscopy, and charge–discharge techniques. Analysis shows that chemically treated activated charcoal electrodes have almost triple times more capacitance values as compared to the untreated one. 相似文献
65.
A. S. Singha Ashish Guleria Raj K. Rana 《International Journal of Polymer Analysis and Characterization》2013,18(6):451-463
The present study explores surface modification of Abelmoschus esculentus by graft copolymerization reaction using acrylonitrile as a monomer and ascorbic acid/H2O2 as a redox initiator. Further, polyacrylonitrile grafted fibers were treated with hydroxylamine to convert the nitrile group of the grafted fiber into the amidoxime group to enhance adsorption of copper ions from wastewater. The graft copolymers and amidoximated fibers were characterized by FT-IR and FE-SEM. The effects of physicochemical parameters such as pH of the solution, initial metal ion concentration, and time on Cu(II) adsorption were studied to optimize condition for maximum adsorption. In addition, Langmuir, Freundlich, and Tempkin models were applied to describe the adsorption isotherm of Cu2+ ions. 相似文献
66.
The α-oxoketene dithioacetals are simple synthetic intermediates widely utilized and implicated for the synthesis of a variety of heterocyclic compounds other than alicyclic and aromatic compounds. They act as 1,3-electrophilic three-carbon synthons. The α-oxoketene dithioacetal of pyrazolone derivatives can be efficiently converted through a base-catalyzed alcoholysis into the corresponding ester in a single one-step reaction with good yield of pure products. In this article, we summarize recent direct conversion of α-oxoketene dithioacetals to highly desirable esters. The overall process is an example of intramolecular rearrangement of bonds. Characterization and identification of all synthesized compounds were assigned through 1H NMR and mass spectroscopy. 相似文献
67.
Dr. Divita Garg Gabriele Gabrieli Dr. Achim Stocker Dr. Tamis Darbre Prof. Dr. Jean‐Louis Reymond 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(50):17054-17063
The galactopeptide dendrimer GalAG2 ((β‐Gal‐OC6H4CO‐Lys‐Pro‐Leu)4(Lys‐Phe‐Lys‐Ile)2Lys‐His‐Ile‐NH2) binds strongly to the Pseudomonas aeruginosa (PA) lectin LecA, and it inhibits PA biofilms, as well as disperses already established ones. By starting with the crystal structure of the terminal tripeptide moiety GalA‐KPL in complex with LecA, a computational mutagenesis study was carried out on the galactotripeptide to optimize the peptide–lectin interactions. 25 mutants were experimentally evaluated by a hemagglutination inhibition assay, 17 by isothermal titration calorimetry, and 3 by X‐ray crystallography. Two of these tripeptides, GalA‐KPY (dissociation constant (KD)=2.7 μM ) and GalA‐KRL (KD=2.7 μM ), are among the most potent monovalent LecA ligands reported to date. Dendrimers based on these tripeptide ligands showed improved PA biofilm inhibition and dispersal compared to those of GalAG2 , particularly G2KPY ((β‐Gal‐OC6H4CO‐Lys‐Pro‐Tyr)4(Lys‐Phe‐Lys‐Ile)2Lys‐His‐Ile‐NH2). The possibility to retain and even improve the biofilm inhibition in several analogues of GalAG2 suggests that it should be possible to fine‐tune this dendrimer towards therapeutic use by adjusting the pharmacokinetic parameters in addition to the biofilm inhibition through amino acid substitutions. 相似文献
68.
Ashish Goyal J.B. Shukla A.K. Misra Ajai Shukla 《Mathematical Methods in the Applied Sciences》2015,38(17):4300-4316
People having extreme idealogies affect the process in a region using fear of terror acts, money power, and the word of mouth communication network to change individuals to their way of thinking. This forces government to divert its limited financial resources for controlling extremism and thus affecting development. In this paper, therefore, a nonlinear mathematical model is proposed to study the dynamics of extremism governed by four dependent variables, namely, number of people in the general population having no extreme ideology, number of extreme ideologists, number of isolated ideologists (prisoners), and the cumulative density of government efforts and their interactions. The model is analyzed using the stability theory of differential equations and computer simulation. The analysis shows that if appropriate level of government efforts is applied on extremists, the spread of their ideology can be controlled in the general population. A numerical study of the model is also carried out to investigate the effects of certain parameters on the spread of extremism confirming the analytical results.Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
69.
Li T Garg U Liu Y Marks R Nayak BK Rao PV Fujiwara M Hashimoto H Kawase K Nakanishi K Okumura S Yosoi M Itoh M Ichikawa M Matsuo R Terazono T Uchida M Kawabata T Akimune H Iwao Y Murakami T Sakaguchi H Terashima S Yasuda Y Zenihiro J Harakeh MN 《Physical review letters》2007,99(16):162503
The strength distributions of the giant monopole resonance (GMR) have been measured in the even-A Sn isotopes (A=112-124) with inelastic scattering of 400-MeV alpha particles in the angular range 0 degrees -8.5 degrees . We find that the experimentally observed GMR energies of the Sn isotopes are lower than the values predicted by theoretical calculations that reproduce the GMR energies in 208Pb and 90Zr very well. From the GMR data, a value of Ktau = -550 +/- 100 MeV is obtained for the asymmetry term in the nuclear incompressibility. 相似文献
70.
Ashish J. Radia Jaydeep N. Lalpara Ishita J. Modasiya Gaurang G. Dubal 《Journal of heterocyclic chemistry》2021,58(2):612-621
A modest, efficient, and mild synthetic procedure has been developed for the synthesis of novel series of 1,3,4-oxadiazole containing azaspirocycles derivatives. The reaction of 1,3,4-oxadiazole derivative with diverse azaspiro compounds under room temperature condition with helps of sodium iodide catalyst and polar aprotic solvent. Numerous compensations of this strategy embrace less time required, yield increment, consumption of all reactants, and mild condition. All synthesized compounds evaluated for in vitro antidiabetic and antibacterial screening. Among them some compounds show significant biological response. 相似文献