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101.
102.
Bulent Ozbas Shigeyuki Toki Benjamin S. Hsiao Benjamin Chu Richard A. Register Ilhan A. Aksay Robert K. Prud'homme Douglas H. Adamson 《Journal of Polymer Science.Polymer Physics》2012,50(10):718-723
The effects of functionalized graphene sheets (FGSs) on the mechanical properties and strain‐induced crystallization of natural rubber (NR) are investigated. FGSs are predominantly single sheets of graphene with a lateral size of several hundreds of nanometers and a thickness of 1.5 nm. The effect of FGS and that of carbon black (CB) on the strain‐induced crystallization of NR is compared by coupled tensile tests and X‐ray diffraction experiments. Synchrotron X‐ray scattering enables simultaneous measurements of stress and crystallization of NR in real time during sample stretching. The onset of crystallization occurs at significantly lower strains for FGS‐filled NR samples compared with CB‐filled NR, even at low loadings. Neat‐NR exhibits strain‐induced crystallization around a strain of 2.25, while incorporation of 1 and 4 wt % FGS shifts the crystallization to strains of 1.25 and 0.75, respectively. In contrast, loadings of 16 wt % CB do not significantly shift the critical strain for crystallization. Two‐dimensional (2D) wide angle X‐ray scattering patterns show minor polymer chain alignment during stretching, in accord with previous results for NR. Small angle X‐ray scattering shows that FGS is aligned in the stretching direction, whereas CB does not show alignment or anisotropy. The mechanical properties of filled NR samples are investigated using cyclic tensile and dynamic mechanical measurements above and below the glass transition of NR. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 相似文献
103.
Bulent Ozbas Christopher D. O'Neill Richard A. Register Ilhan A. Aksay Robert K. Prud'homme Douglas H. Adamson 《Journal of Polymer Science.Polymer Physics》2012,50(13):910-916
We demonstrate the use of functionalized graphene sheets (FGSs) as multifunctional nanofillers to improve mechanical properties, lower gas permeability, and impart electrical conductivity for several distinct elastomers. FGS consists mainly of single sheets of crumbled graphene containing oxygen functional groups and is produced by the thermal exfoliation of oxidized graphite (GO). The present investigation includes composites of FGS and three elastomers: natural rubber (NR), styrene–butadiene rubber, and polydimethylsiloxane (PDMS). All of these elastomers show similar and significant improvements in mechanical properties with FGS, indicating that the mechanism of property improvement is inherent to the FGS and not simply a function of chemical crosslinking. The decrease in gas permeability is attributed to the high aspect ratio of the FGS sheets. This creates a tortuous path mechanism of gas diffusion; fitting the permeability data to the Nielsen model yields an aspect ratio of ~1000 for the FGS. Electrical conductivity is demonstrated at FGS loadings as low as 0.08% in PDMS and reaches 0.3 S/m at 4 wt % loading in NR. This combination of functionalities imparted by FGS is shown to result from its high aspect ratio and carbon‐based structure. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 相似文献
104.
Jalil Manafian Onur Alp Ilhan Ladan Avazpour As'ad Alizadeh 《Mathematical Methods in the Applied Sciences》2020,43(17):9904-9927
The present article deals with M-soliton solution and N-soliton solution of the (2 + 1)-dimensional asymmetrical Nizhnik–Novikov–Veselov equation by virtue of Hirota bilinear operator method. The obtained solutions for solving the current equation represent some localized waves including soliton, breather, lump, and their interactions, which have been investigated by the approach of the long-wave limit. Mainly, by choosing the specific parameter constraints in the M-soliton and N-soliton solutions, all cases of the one breather or one lump can be captured from the two, three, four, and five solitons. In addition, the performances of the mentioned technique, namely, the Hirota bilinear technique, are substantially powerful and absolutely reliable to search for new explicit solutions of nonlinear models. Meanwhile, the obtained solutions are extended with numerical simulation to analyze graphically, which results in localized waves and their interaction from the two-, three-, four-, and five-soliton solutions profiles. They will be extensively used to report many attractive physical phenomena in the fields of acoustics, heat transfer, fluid dynamics, classical mechanics, and so on. 相似文献
105.
This paper studies torsional wave dispersion in a three-layered (sandwich) hollow cylinder with finite initial strains. The investigations are carried out within the scope of the piecewise homogeneous body model with the use of the three-dimensional linearized theory of elastic waves in initially stressed bodies. The mechanical relations of the materials of the cylinders are described through their harmonic potential. The analytical expression is obtained for the low wavenumber limit values of the torsional wave propagation velocity. The numerical results on the influence of the initial stretching or compression of the cylinders along the torsional wave propagation direction are presented and discussed. 相似文献
106.
Utility of the Pfitzinger Reaction in the Synthesis of Novel Quinoline Derivatives and Related Heterocycles
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Derviş Gök Rahmi Kasımoğulları Mustafa Cengiz Samet Mert 《Journal of heterocyclic chemistry》2014,51(1):224-232
2‐(2‐Amino‐3,5‐dinitrophenyl)‐2‐oxoacetic acid ( 2 ) was obtained from hydrolysis of 5,7‐dinitroisatin ( 1 ) in alkaline media. A novel quinoxaline derivative ( 3 ) was synthesized from the reaction of the same compound ( 1 ) with o‐phenylenediamine. Reacting 2 with ethyl 3‐oxo‐3‐phenylpropanoate yields 6,8‐dinitro‐2‐phenylquinoline‐3,4‐dicarboxylic acid ( 4 ). Then, 4 was converted into new quinoline‐diacylchloride, quinoline‐ester, quinoline‐dicarboxamide, pyridazine, and pyrroledione derivatives ( 5 , 6a , 6b , 6c , 6d , 7a , 7b , 7c , 7d , 8 , 9 , 10a , 10b , 10c , 10d , 11a , 11b , 12 ) with SOCl2, alcohols, amines, and hydrazines, respectively. The structures of synthesized compounds were clarified by 1H NMR, 13C NMR, IR, mass and elemental analysis methods. 相似文献
107.
As a consequence of more extensive collaboration between countries, the need for better humanitarian relief assistance has
become a significant challenge to the international community. In case of a disaster exceeding the national response capacity
of the affected country, donor countries provide the relief items, which are then consolidated at collection points to be
shipped to points of delivery in the stricken country. After the items are transported to the point of delivery, the responsible
authority in distributing aids to vulnerable populations then becomes the national relief agencies. In this context, we propose
an international relief planning model that can handle the uncertain information while maximizing the credibility of the international
agencies in the most cost efficient way. 相似文献
108.
The method which we call the Weighted Averaging Based on Levels (WABL) can be used to calculate the average representative
of a fuzzy number. It utilizes weight coefficients for the level sets as well as the sides of a fuzzy number. We have developed
an algorithm to obtain these coefficients. The most remarkable feature of this algorithm is that it makes use of the decision
maker’s (DM) aggregation strategy. 相似文献
109.
Duran Karakas Ilhan Olmez Gurdal Tuncel 《International journal of environmental analytical chemistry》2013,93(10):705-720
Instrumental neutron activation analysis, flame atomic absorption spectrometry, flame atomic emission spectrometry, graphite furnace atomic absorption spectrometry, ion chromatography and visible spectrometry were applied to determine the compositions of atmospheric aerosols, which were collected at a rural site in the Western Black Sea Coast of Turkey. A total of 354 daily aerosol samples were analyzed for about 46 trace and major elements and ions. Sample preparation, quality control procedures, and instrumental operating conditions were reported. Most of the elements measured commonly by the above techniques have very large correlation coefficients and low intercept values indicating the agreement between the results. 相似文献
110.
Fadime Mert‐Balci Hans‐Georg Imrich Jürgen Conrad Uwe Beifuss 《Helvetica chimica acta》2013,96(9):1681-1692
The three‐component reaction of aniline, benzaldehyde, and dienophiles such as 2,3‐dihydrofuran, ethyl vinyl ether, 2,3‐dihydropyran, and cyclopentadiene can be promoted by ionic liquids like imidazolium salts and guanidinium salts under thermal as well as microwave conditions. The chemical yield as well as the diastereoselectivity of the Povarov reaction strongly depend on the ionic liquid employed. The guanidinium salts can be recycled and reused several times without loss of reactivity. 相似文献