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101.
102.
103.
Design of Advanced MnO/N‐Gr 3D Walls through Polymer Cross‐Linking for High‐Performance Supercapacitor
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Ngoc Quang Tran Dr. Bong Kyun Kang Sintayehu Nibret Tiruneh Prof. Dae Ho Yoon 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(5):1652-1657
Three‐dimensional, vertically aligned MnO/nitrogen‐doped graphene (3D MnO/N‐Gr) walls were prepared through facile solution‐phase synthesis followed by thermal treatment. Polyvinylpyrrolidone (PVP) was strategically added to generate cross‐links to simultaneously form 3D wall structures and to incorporate nitrogen atoms into the graphene network. The unique wall features of the as‐prepared 3D MnO/N‐Gr hybirdes provide a large surface area (91.516 m2 g?1) and allow for rapid diffusion of the ion electrolyte, resulting in a high specific capacitance of 378 F g?1 at 0.25 A g?1 and an excellent charge/discharge stability (93.7 % capacity retention after 8000 cycles) in aqueous 1 m Na2SO4 solution as electrolyte. Moreover, the symmetric supercapacitors that were rationally designed by using 3D MnO/N‐Gr hybrids exhibit outstanding electrochemical performance in an organic electrolyte with an energy density of 90.6 Wh kg?1 and a power density of 437.5 W kg?1. 相似文献
104.
Si Bui Quang Tran Doyoung Byun Vu Dat Nguyen Hadi Teguh Yudistira Myoung Jong Yu Kyun Ho Lee Jaeuk U. Kim 《Journal of Electrostatics》2010,68(2):138-144
In this paper, “end effect”, which represents the deflection of meniscus of boundary nozzles in an array due to asymmetric electric field and repulsive forces between adjacent nozzles, is experimentally investigated and a polymer-based electrospray device is fabricated and tested to minimize the end effect. For the electrically conductive nozzles of electrospray, the end effect could be reduced by dummy nozzles, through which no liquid is supplied, mounted at the boundary of the array. However, the polymer-based electrospray device can eliminate the end effect without using the dummy dry nozzles due to dielectric characteristic. A novel multiple nozzles of Polymethyl Methacrylate (PMMA)-based electrospray device was successfully fabricated and evaluated for reducing the end effect, showing no deflection of menisci through the boundary nozzles. And ten nozzles device was fabricated and observed to eject liquid jet simultaneously. The electrical current of the spray issued from the nozzles of the polymer-based electrospray device is measured with respect to flow rate and shows a good agreement with the scaling law. 相似文献
105.
In this paper nonstandard finite difference (NSFD) schemes of two metapopulation models are constructed. The stability properties of the discrete models are investigated by the use of the Lyapunov stability theorem. As a result of this we have proved that the NSFD schemes preserve essential properties of the metapopulation models (positivity, boundedness and monotone convergence of the solutions, equilibria and their stability properties). Especially, the basic reproduction number of the continuous models is also preserved. Numerical examples confirm the obtained theoretical results of the properties of the constructed difference schemes. The method of Lyapunov functions proves to be much simpler than the standard method for studying stability of the discrete metapopulation model in our very recent paper. 相似文献
106.
A.N. Ulyanov H.D. Quang N.E. Pismenova S.C. Yu G.G. Levchenko 《Solid State Communications》2012,152(16):1556-1559
We present a systematic experimental study of single phase Pr0.7Ca0.15Ba0.15MnO3 manganites. Ferromagnetic insulating state is observed in wide temperature range between the Curie point and peak resistivity temperature. Two approaches for the analysis of the electron paramagnetic resonance (EPR) line-width (ΔH) were considered in details. The first approach is based on the proportionality between the temperature dependencies of resistivity and inverse ΔH. The second approach is based on the model where ΔH∝1/Tχdc (χdc is a static magnetic susceptibility). For the studied Pr0.7Ca0.15Ba0.15MnO3 manganites the resistivity, associated with the grain boundary scattering, follows Mott law; the EPR line-width, suggested to be an intrinsic property, is well described with polaron hopping model. 相似文献
107.
Stanisław Boryczka Kinga Suwińska Georges Le Guillanton Quang Tho Do Driss Elothmani 《Journal of chemical crystallography》1998,28(7):555-560
The title compound (C14H11NO2) is monoclinic with a = 13.579(2), b = 5.297(1), c = 16.455(2) Å, = 98.11(2)°, Z = 4, and space group P21/n. The significant structural features lie in the two carbonyl groups of the glyoxamide which are oriented antiperiplanar to each other [–163.6(3)°]. The central bond C(1)–C(2) is 1.545(4) Å. The observed conformation is stabilized by intramolecular hydrogen bonds. 相似文献
108.
Jean-Luc Fauchre Susanne Pfenninger Kim Quang Do Carole Lemieux Peter W. Schiller 《Helvetica chimica acta》1983,66(4):1053-1060
Converging data obtained in biochemical and pharmacological bioassays for opiate activity are presented for five new enkephalin-like peptides. The main structural features of the analogues, the synthesis of which is described in detail, were the presence of D -alanine or D -serine in position 2, p-nitrophenylalanine in position 4 and of a free C-terminal carboxylic function. Confirming our previous observations [1], the substitution of phenylalanine by p-nitrophenylalanine enhanced the overall opiate activity but decreased the selectivity towards m?/δ-receptor sites. Tyrosyl-D -alanyl-glycyl-p-nitrophenylalanyl-adamantylalanine was particularly potent in all assays while tyrosyl-D -seryl-glycyl-p-nitrophenylalanyl-leucyl-threonine was very selective in the bioassays on isolated tissues and moderately selective in the binding assay. These results will have to be taken into account in future photoaffinity labelling and quantitative structure-activity relationships (QSAR) studies. 相似文献
109.
Four new azaphilones named sassafrins A-D (1-4) were isolated from the methanol extract of the stromata of the fungus Creosphaeria sassafras (Xylariaceae, Ascomycetes). Their structures were elucidated by 2D NMR, HR-MS, IR, UV and CD spectroscopy. Sassafrin D (4) possesses a novel skeleton and its biosynthetic pathway is also discussed. In addition, all compounds showed broad-spectrum antimicrobial activity. Their apparently unique occurrence in C. sassafras supports the status of this fungus as a member of a distinct genus within the Xylariaceae, coinciding with molecular and morphological traits. 相似文献
110.
Roger Petiaud Quang Tho Pham 《Journal of polymer science. Part A, Polymer chemistry》1985,23(5):1343-1360
A microstructure analysis of polychloroprenes by 1H and 13C NMR produced slightly different results which, however, are in good agreement. The main uncertainty concerned the assignment of the 1,4-cis and trans head-to-head and tail-to-tail additions. In the (+ 12, +70°C) region of polymerization temperatures the principal addition mode was 1,4. An increase in the polymerization temperature to 70°C increased the abnormal head-to-head, tail-to-tail additions, and 1,4-cis additions (6–7%), and all vinyl structures that were not higher than 2–3% were equally distributed between 1,2 and 3,4. Under the experimental conditions used in this study no isomerized vinyl structures were found. As in all radical polymerizations the influence of temperature on the propagation mechanisms, namely, the addition modes, was relatively weak, but because of the great number of possible addition modes in microstructure—physicomechanical relationships variations in the microstructure must be taken into account. Only 1H and 13C NMR are capable of determining these variations quantitatively. 相似文献