In the present study, the influence of citric acid (CA) on hydrogel films composed of sodium carboxymethylcellulose (NaCMC), hydroxypropylmethylcellulose (HPMC), and CuO nanoflakes was investigated for their physicochemical, mechanical, thermal, and antibacterial properties. XRD patterns showed that the prepared hydrogel films revealed the crystalline phase for CuO/Cu2O/Cu at 20% CA concentration. Laser micro-Raman spectroscopy confirmed the presence of CuO and Cu2O in the films. Increase in CA concentration decreased the swelling degree and tensile strength and increased the decomposition temperature of NaCMC, HPMC, and CuO. According to FESEM and FETEM results, shape and size of CuO nanoflakes were completely changed into spherical nanoparticles with increase in CA concentration. HRTEM and inverse Fourier transform images showed that the d-spacing of CuO, Cu2O, and Cu were correlated with XRD results. The prepared hydrogel films exhibited significant antibacterial activity and biocompatibility against HaCaT cells. All these data recommend that the prepared hydrogel films may be used for potential wound healing applications. 相似文献
Highly flexible supercapacitors (SCs) have great potential in modern electronics such as wearable and portable devices. However, ultralow specific capacity and low operating potential window limit their practical applications. Herein, a new strategy for the fabrication of free‐standing Ni?Mo?S and Ni?Fe?S nanosheets (NSs) for high‐performance flexible asymmetric SC (ASC) through hydrothermal and subsequent sulfurization technique is reported. The effect of Ni2+ is optimized to attain hierarchical Ni?Mo?S and Ni?Fe?S NS architectures with high electrical conductivity, large surface area, and exclusive porous networks. Electrochemical properties of Ni?Mo?S and Ni?Fe?S NS electrodes exhibit that both have ultrahigh specific capacities (≈312 and 246 mAh g?1 at 1 mA cm?2), exceptional rate capabilities (78.85% and 78.46% capacity retention even at 50 mA cm?2, respectively), and superior cycling stabilities. Most importantly, a flexible Ni?Mo?S NS//Ni?Fe?S NS ASC delivers a high volumetric capacity of ≈1.9 mAh cm?3, excellent energy density of ≈82.13 Wh kg?1 at 0.561 kW kg?1, exceptional power density (≈13.103 kW kg?1 at 61.51 Wh kg?1) and an outstanding cycling stability, retaining ≈95.86% of initial capacity after 10 000 cycles. This study emphasizes the potential importance of compositional tunability of the NS architecture as a novel strategy for enhancing the charge storage properties of active electrodes. 相似文献
Journal of Materials Science: Materials in Electronics - In this present research, heterostructure NiO–SnO2 nanocomposite modified electrode was developed to determine l-cysteine molecule.... 相似文献
Journal of Materials Science: Materials in Electronics - Zinc Oxide/Nickel Oxide (ZnO/NiO) heterostructures were deposited using the spray pyrolysis technique by varying NiO content. The X-ray... 相似文献
The recent communication receiver requires compact size, low cost, less weight and high-performance antenna for broadband applications. This paper compares the performance of the microstrip patch antenna designed using h-BN nano ceramic substrate with antenna designed using FR4 substrate. In this proposed new substrate is developed using powder metallurgy principle. Simulated and experimental results shows that proposed substrate for patch antenna in S-band applications achieve good resonance at two different frequencies 2.2 and 2.6 GHz with reflection coefficient of ?35 and ?40 dB respectively. Same antenna structure using FR4 structure is achieving good resonance at multiple frequency and broadband characteristics in C-band and X-band of the radio spectrum.
A slip-line field model for orthogonal cutting with chip breaker and flank wear has been developed. For a worn tool, this slip-line field includes a primary deformation zone with finite thickness; two secondary shear zones, one along the rake face and the other along the flank face; a predeformation zone; a curled chip; and a flank force system. It is shown that the cutting geometry is completely determined by specifying the rake angle, tool-chip interface friction and the chip breaker constraint. The chip radius of curvature, chip thickness, and the stresses and velocities within the plastic region are readily computed. Grid deformation patterns, calculated with the velocity field determined, demonstrate that the predicted effects of changes in frictional conditions at the tool-chip interface and of the rake angle on chip formation are in accord with experimental observations. The calculated normal stress distribution at the tool-chip interface is in general agreement with previously reported experimental measurements. The model proposed predicts a linear relationship between flank wear and cutting force components. The results also show that non-zero strains occur at and below the machined surface when machining with a worn tool. Severity and depth of deformation below the machined surface increases with increasing flank wear. Forces acting on the chip breaker surface are found to be small and suggest that chip control for automated machining may be feasible with other means. 相似文献
Nano particle of Fe3O4 (nFe3O4) up to 6 at% were doped in the superconducting MgB2 samples. Despite the strong ferromagnetic nature of Fe3O4, both the ac susceptibility and the resistivity measurements show that up to 4 at% of Fe3O4, Tc=38 K is not changed, whereas for 6% Tc decreases by 6 K. This indicates that a low concentration of Fe does not substitute either the Mg or B sites and probably
occupies the intergrain spaces. For 0.5% doped Fe3O4, an increase in Jc with respect to the pure MgB2 samples is observed in the lower field and temperature regions (H<2 T and 20 K) indicating an enhanced flux pinning and the magnetic activation, i.e., the interaction between the magnetic
dipole of Fe ion and the vortices is weak in comparison to the effective pinning potential. Whereas, at H>2 T, Jc of the doped samples is always less than that of MgB2, and the activation is dominant in comparison with the effective pinning potential provided by the doping. Flux jumps are
observed in lower T and H regions for the samples doped up to 1% nFe3O4 only. Magnetization plots of higher Fe content samples exhibited clear paramagnetic background. Mossbauer measurements for
the higher (4, 6 at%) nFe3O4 doped MgB2 samples show that at RT, the hyperfine field for both samples is ∼100 kOe and ∼120 kOe at 90 K. This means that the nFe3O4 particles decompose and form possibly an intermetallic Fe-B phase in the matrix. 相似文献
In the present study, the influence of Hall and ion‐slip current on steady magnetohydrodynamics mixed convective, Ohmic heating, and viscous dissipative Casson fluid flow over an infinite vertical porous plate in the presence of Soret effect and chemical reaction are investigated. The modeling equations are transformed into dimensionless equations and then solved analytically through the multiple regular perturbation law. Computations are performed graphically to analyze the behavior of fluid velocity, temperature, concentration, skin friction, Nusselt number, and Sherwood number on the vertical plate with the difference of emerging physical parameters. This study reflects that the incremental values of Casson fluid parameter and Schmidt number lead to reduction in velocity. However, fluid velocity rises due to enhancement of ion‐slip parameter but an opposite effect is observed in case of Hall parameter. In addition, the Sherwood number declines with enhancing dissimilar estimators of the chemical reaction, Schmidt number, as well as Soret number. 相似文献
The multiple knapsack problem (MKP) forms a base for resolving many real-life problems. This has also been considered with multiple objectives in genetic algorithms (GAs) for proving its efficiency. GAs use self-adaptability to effectively solve complex problems with constraints, but in certain cases, self-adaptability fails by converging toward an infeasible region. This pitfall can be resolved by using different existing repairing techniques; however, this cannot assure convergence toward attaining the optimal solution. To overcome this issue, gene position-based suppression (GPS) has been modeled and embedded as a new phase in a classical GA. This phase works on the genes of a newly generated individual after the recombination phase to retain the solution vector within its feasible region and to improve the solution vector to attain the optimal solution. Genes holding the highest expressibility are reserved into a subset, as the best genes identified from the current individuals by replacing the weaker genes from the subset. This subset is used by the next generated individual to improve the solution vector and to retain the best genes of the individuals. Each gene’s positional point and its genotype exposure for each region in an environment are used to fit the best unique genes. Further, suppression of expression in conflicting gene’s relies on the requirement toward the level of exposure in the environment or in eliminating the duplicate genes from the environment. TheMKP benchmark instances from the OR-library are taken for the experiment to test the new model. The outcome portrays that GPS in a classical GA is superior in most of the cases compared to the other existing repairing techniques. 相似文献
In order to check the solubility of Zn in the (Sr1?xZnx)CoO3 perovskite structure and their research findings, several polycrystalline samples have been prepared under wide extreme synthesis conditions at 6?GPa/1300?C1650?°C. While 0.05??x??0.3 compositions revealed single phased cubic structure materials, x>0.3 showed multi-phased materials for (Sr1?xZnx)CoO3 system. Like other substituted perovskite cobalt oxide systems (Ca, Y, Ho and Ce), the transport properties of the present materials show rather sizable changes with respect to ??x??, although there are insignificant variations in lattice parameter and in Curie temperature, Tc. All the present samples show soft ferromagnetism with Tc in the range of 272?C285?K for 0.05??x??0.3. The effective paramagnetic moment, Peff determined from the paramagnetic region decreases upon the substitution of Zn for Sr-site. These Peff (3.3?C2.8???B/Co) values for 0.05??x??0.3 compositions seem to suggest that the Co4+ lie in intermediate spin (IS) state for the present (Sr1?xZnx)CoO3 series, although they are slightly smaller than those expected for IS-Co4+; Peff=3.87???B/Co. The electrical resistivity is found to increase with increase of ??x?? for the investigated samples. The temperature and field dependence of both positive and negative magnetoresistance (MR) are noted for the Zn substituted samples. About 5% of ?CMR is observed for x=0.05 sample around the transition temperature (280?K) under the field strength difference, ??H=90?kOe. The present research findings are compared with our previous results on different perovskite cobalt oxides. 相似文献