排序方式: 共有95条查询结果,搜索用时 21 毫秒
51.
Ahmet Örnek Emrah Bulut Mustafa Can Mahmut Özacar 《Journal of Solid State Electrochemistry》2013,17(12):3101-3107
Pure LiFePO4 and LiNi x Fe1?x PO4/C (x?=?0.00–0.20) nanocomposite cathode materials have been synthesized by cheap and convenient sol–gel-assisted carbothermal reduction method. X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy, and inductively coupled plasma have been used to study the phase, morphology, and chemical composition of un-doped and Ni-doped materials. XRD patterns display the slight shrinkage in crystal lattice of LiFePO4 after Ni2+ doping. The SEM images have revealed that Ni-doped particles are not agglomerated and the particle sizes are practically homogeneously distributed. The particle size is found between 50 and 100 nm for LiNi0.20Fe0.80PO4/C sample. The discharge capacity at 0.2 C rate has increased up to 155 mAh g?1 for the LiNi0.05Fe0.95PO4/C sample and good capacity retention of 99.1 % over 100 cycles, while that of the unsubstituted LiFePO4/C and pure LiFePO4 has showed only 122 and 89 mAh g?1, respectively. Doping with Ni has a noticeable effect on improving its electrical conductivity. However, serious electrochemical declension will occur when its doping density is beyond 0.05 mol LiNi0.20Fe0.80PO4/C electrode shows only 118 mAh g?1, which is less than un-doped LiFePO4/C sample at 0.2 C. The cycling voltammogram demonstrates that Ni-doped LiNi0.05Fe0.95PO4/C electrode has more stable lattice structure, enhanced conductivity, and diffusion coefficient of Li+ ions, in which Ni2+ is regarded to act as a column in crystal lattice structure to prevent the collapse during cycling process. 相似文献
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Nevroz Aslan Ertas Emrah Kavak Frat Salman Hilal Celik Kazici Hilal Kivrak Arif Kivrak 《Electroanalysis》2020,32(6):1178-1185
At present, a highly sensitive hydrogen peroxide (H2O2) sensor is fabricated by ferrocene based naphthaquinone derivatives as 2,3‐Diferrocenyl‐1,4‐naphthoquinone and 2‐bromo‐3‐ferrocenyl‐1,4‐naphthoquinone. These ferrocene based naphthaquinone derivatives are characterized by H‐NMR and C‐NMR. The electrochemical properties of these ferrocene based naphthaquinone are investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) on modified glassy carbon electrode (GCE). The modified electrode with ferrocene based naphthaquinone derivatives exhibits an improved voltammetric response to the H2O2 redox reaction. 2‐bromo‐3‐ferrocenyl‐1,4‐naphthoquinone show excellent non‐enzymatic sensing ability towards H2O2 response with a detection limitation of 2.7 μmol/L a wide detection range from 10 μM to 400 μM in H2O2 detection. The sensor also exhibits short response time (1 s) and good sensitivity of 71.4 μA mM?1 cm?2 and stability. Furthermore, the DPV method exhibited very high sensitivity (18999 μA mM?1 cm?2) and low detection limit (0.66 μM) compared to the CA method. Ferrocene based naphthaquinone derivative based sensors have a lower cost and high stability. Thus, this novel non‐enzyme sensor has potential application in H2O2 detection. 相似文献
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We report the development of a chitosan modified carbon fiber microelectrode for in vivo detection of serotonin. We find that chitosan has the ability to reject physiological levels of ascorbic acid interferences and facilitate selective and sensitive detection of in vivo levels of serotonin, a common catecholamine neurotransmitter. Presence of chitosan on the microelectrode surface was investigated using scanning electron microscopy (SEM) and cyclic voltammetry (CV). The electrode was characterized using differential pulse voltammetry (DPV). A detection limit of 1.6 nM serotonin with a sensitivity of 5.12 nA/μM, a linear range from 2 to 100 nM and a reproducibility of 6.5% for n=6 electrodes were obtained. Chitosan modified microelectrodes selectively measure serotonin in presence of physiological levels of ascorbic acid. In vivo measurements were performed to measure concentration of serotonin in the live embryonic zebrafish intestine. The sensor quantifies in vivo intestinal levels of serotonin while successfully rejecting ascorbic acid interferences. We demonstrate that chitosan can be used as an effective coating to reject ascorbic acid interferences at carbon fiber microelectrodes, as an alternative to Nafion, and that chitosan modified microelectrodes are reliable tools for in vivo monitoring of changes in neurotransmitter levels. 相似文献
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In this article, using generalized weighted mean and difference matrix of order m, we introduce the paranormed sequence space ?(u, v, p; Δ(m)), which consist of the sequences whose generalized weighted Δ(m)-difference means are in the linear space ?(p) defined by I.J. Maddox. Also, we determine the basis of this space and compute its α-, β- and γ-duals. Further, we give the characterization of the classes of matrix mappings from ?(u, v, p, Δ(m)) to ?∞, c and c0. Finally, we apply the Hausdorff measure of noncompacness to characterize some classes of compact operators given by matrices on the space ?p(u, v, Δ(m))(1 ≤ p < ∞). 相似文献
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In this study, a novel three functional chain extender(TATATRIOL) was synthesized from the reaction of 1,3,5-tri(prop-2-en-1-yl)-1,3,5-triazinane-2,4,6-trione(TATA) with 2-sulfanylethanol. Then new thermoplastic polyurethanes(TPUs) were synthesized by a one-step bulk polymerization from the reaction of 1,1'-methanediylbis(4-isocyanatocyclohexane)(H12MDI), a poly(ethylene adipate) based polyester polyol and a chain extender. Butane-1,4-diol(BD) and the newly synthesized monomer, TATATRIOL, were used as chain extenders. The effects of TATATRIOL on the properties of the TPU were investigated and compared to those of the TPU prepared with BD. The TPUs which derived from the sulfur containing chain extender displayed lower modulus and high elongation at break values than the analogous TPUs derived from BD. Moreover sulfur containing TPUs exhibited higher thermal stability. 相似文献
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Nizami A. Gasilov Şahin Emrah Amrahov 《Mathematical Methods in the Applied Sciences》2020,43(4):1825-1837
In this study, a new approach is developed to solve the initial value problem for interval linear differential equations. In the considered problem, the coefficients and the initial values are constant intervals. In the developed approach, there is no need to define a derivative for interval-valued functions. All derivatives used in the approach are classical derivatives of real functions. The reason for this is that the solution of the problem is defined as a bunch of real functions. Such a solution concept is compatible also with the robust stability concept. Sufficient conditions are provided for the solution to be expressed analytically. In addition, on a numerical example, the solution obtained by the proposed approach is compared with the solution obtained by the generalized Hukuhara differentiability. It is shown that the proposed approach gives a new type of solution. The main advantage of the proposed approach is that the solution to the considered interval initial value problem exists and is unique, as in the real case. 相似文献
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Emrah?Karaman Mustafa?Soyertem ?lknur?Atasever Güven?Email author Didem?Tozkan Mahide?Kü?ük Yal??n?Kü?ük 《Positivity》2018,22(3):783-802
In this study, some new order relations on family of sets are introduced by using Minkowski difference. The relations between these orders and the ordering cone of the vector space are obtained. It is shown that depending on the corresponding cone, these order relations are partial orders on the family of nonempty bounded sets. Some relationships between these order relations and upper and lower set less order relations are investigated. Also, two scalarizing functions are introduced in order to replace set optimization problems with respect to these partial order relations with scalar optimization problems. Moreover, necessary and sufficient optimality conditions are presented. 相似文献