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Multimedia Tools and Applications - Background Subtraction (BS) plays an important role in video surveillance system because it provides a focus of attention for moving object detection. But there...  相似文献   
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Nanoparticles of platinum and hydrous molybdenum oxide (Pt/HxMoO3) were successfully electrodeposited onto poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT-PSS) film by chronocoulometry (0.2 C). Various loadings of Pt/HxMoO3 particles onto the PEDOT-PSS electrode were achieved using the co-deposition technique. The existence of Pt/HxMoO3 particles was determined through characterization by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis. XPS results revealed that deposited Pt and molybdenum were metallic Pt and HxMoO3, respectively. XRD analysis showed a decrease of Pt crystalline facets for the incorporation of HxMoO3 into PEDOT-PSS-Pt, indicating a strong interaction between Pt and HxMoO3. Scanning electron microscopy (SEM) results revealed a uniform dispersion of Pt/HxMoO3 particles, with the particle size of 70–90 nm, in the PEDOT-PSS matrix. The cyclic voltammetry study and chronopotentiometry measurements demonstrated that the PEDOT-PSS-Pt/HxMoO3 electrode had superior electrocatalytic activity of methanol oxidation with less CO poisoning. The presence of amorphous HxMoO3 particles on the Pt surface minimized CO poisoning of methanol oxidation.  相似文献   
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The oxygen reduction activity and methanol tolerance of Pt–Bi/C electrocatalysts were studied using electrochemical voltammetric techniques including rotating ring-disk electrode. The Pt–Bi/C catalyst was prepared via a polyol method and subjected to heat treatment to increase the degree of alloying. X-ray diffraction studies revealed the unalloyed character of the as-prepared catalyst and alloy formation upon heat treatment. The electrochemical behaviour of both catalysts showed different behaviour in dilute acid electrolytes, namely sulphuric and perchloric acids. In both electrolytes, the oxygen reduction reaction was found to occur via the four-electron process revealing that the mechanism of oxygen reduction is unaltered even in the presence of excess of methanol. Pt–Bi/C catalyst material showed dramatically different properties and reactivity with respect to oxygen reduction activity and methanol tolerance in perchloric and sulphuric acids. The onset potential for oxygen reduction reaction (ORR) significantly shifted by about 100 mV to more negative values and at the same time the current density was significantly enhanced. This type of non-ideal methanol-tolerant behaviour among Pt bimetallics and a “trade off” is common with all the known so-called methanol tolerant combinations of Pt. In general, the Pt–Bi surface appeared to have a negligibly lesser sensitivity towards methanol activity compared to pure platinum.  相似文献   
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Atomically precise nanoclusters (NCs) have recently emerged as ideal building blocks for constructing self-assembled multifunctional superstructures. The existing structures are based on various non-covalent interactions of the ligands on the NC surface, resulting in inter-NC interactions. Despite recent demonstrations on light-induced reversible self-assembly, long-range reversible self-assembly based on dynamic covalent chemistry on the NC surface has yet to be investigated. Here, it is shown that Au25 NCs containing thiolated umbelliferone (7-hydroxycoumarin) ligands allow [2+2] photocycloaddition reaction-induced self-assembly into colloidal-level toroids. The toroids upon further irradiation undergo inter-toroidal reaction resulting in macroscopic supertoroidal honey-comb frameworks. Systematic investigation using electron microscopy, atomic force microscopy (AFM), and electron tomography (ET) suggest that the NCs initially form spherical aggregates. The spherical structures further undergo fusion resulting in toroid formation. Finally, the toroids fuse into macroscopic honeycomb frameworks. As a proof-of-concept, a cross-photocycloaddition reaction between coumarin-tethered NCs and an anticancer drug (5-fluorouracil) is demonstrated as a model photo-controlled drug release system. The model system allows systematic loading and unloading of the drug during the assembly and disassembly under two different wavelengths. The results suggest that the dynamic covalent chemistry on the NC surface offers a facile route for hierarchical multifunctional frameworks and photocontrolled drug release.  相似文献   
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Nowadays, Wireless Sensor Network (WSN) is a modern technology with a wide range of applications and greatly attractive benefits, for example, self-governing, low expenditure on execution and data communication, long-term function, and unsupervised access to the network. The Internet of Things (IoT) is an attractive, exciting paradigm. By applying communication technologies in sensors and supervising features, WSNs have initiated communication between the IoT devices. Though IoT offers access to the highest amount of information collected through WSNs, it leads to privacy management problems. Hence, this paper provides a Logistic Regression machine learning with the Elliptical Curve Cryptography technique (LRECC) to establish a secure IoT structure for preventing, detecting, and mitigating threats. This approach uses the Elliptical Curve Cryptography (ECC) algorithm to generate and distribute security keys. ECC algorithm is a light weight key; thus, it minimizes the routing overhead. Furthermore, the Logistic Regression machine learning technique selects the transmitter based on intelligent results. The main application of this approach is smart cities. This approach provides continuing reliable routing paths with small overheads. In addition, route nodes cooperate with IoT, and it handles the resources proficiently and minimizes the 29.95% delay.  相似文献   
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The current investigation addresses the alternating current electrical properties, electrochemical characteristics on biopolymer as Withania somnifera leaf extract incorporated sodium alginate [WLISA] polymer film prepared by solution casting method. Some crystallinity along with the amorphous nature of sodium alginate emerged due to the incorporation of Withania somnifera leaf extract [WSLE]. Two absorption maximum (λmax) were obtained for both WLISA and WSLE samples in the UV–Vis spectrum. The blue, green, and red emission of WSLE and weak blue emission of WLISA are studied by PL analysis. The more amount of strain that occurred in crystallization provides broaden peak in X-ray diffraction pattern. With aid of guluronic and mannuronic acids in sodium alginate making hydroxyl bond formation with leaf extract due to the cross-linking process can be analyzed from Fourier transform infrared spectroscopy. The EDAX analysis showed the chemical composition of WSLE. At room temperature, the prepared 5 ml leaf extract WLISA film has demonstrated the highest ionic conductivity in the typical value of 2.80?×?10–6 S/Cm. The electrochemical window of the prepared polymer film is in the range of ? 0.4 to 0.4 V suggesting that used as an electrolyte for supercapacitor applications.

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Multimedia Tools and Applications - Nowadays, thermal image processing has gained more attention. Thermal camera’s cost is decreasing, and so many real-time applications use thermal cameras...  相似文献   
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Carbon-supported Pt–Sn/C bimetallic nanoparticle electrocatalysts were prepared by the simple reduction of the metal precursors using ethylene glycol. The catalysts heat-treated under argon atmosphere to improve alloying of platinum with tin. As-prepared Pt–Sn bimetallic nanoparticles exhibit a single-phase fcc structure of Pt and heat-treatment leading to fcc Pt75Sn25 phase and hexagonal alloy structure of the Pt50Sn50 phase. Transmission electron microscopy image of the as-prepared Pt–Sn/C catalyst reveals a mean particle diameter of ca. 5.8 nm with a relatively narrow size distribution and the particle size increased to ca. 20 nm when heat-treated at 500 °C due to agglomeration. The electrocatalytic activity of oxygen reduction assessed using rotating ring disk electrode technique (hydrodynamic voltammetry) indicated the order of electrocatalytic activity to be: Pt–Sn/C (as-prepared) > Pt–Sn/C (250 °C) > Pt–Sn/C (500 °C) > Pt–Sn/C (600 °C) > Pt–Sn/C (800 °C). Kinetic analysis reveals that the oxygen reduction reaction on Pt–Sn/C catalysts follows a four-electron process leading to water. Moreover, the Pt–Sn/C catalyst exhibited much higher methanol tolerance during the oxygen reduction reaction than the Pt/C catalyst, assessing that the present Pt–Sn/C bimetallic catalyst may function as a methanol-tolerant cathode catalyst in a direct methanol fuel cell.  相似文献   
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