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991.
992.
Chromium was deposited on steel substrates using direct current pulsed high frequency and pulsed low frequency plating methods. The samples obtained from the different plating techniques were later exposed to a corrosive NaCl solution. The time of exposure was varied, for 0, 80 and 140 hours and later the samples were subjected to impedance measurements. In the present study an attempt has been made to characterise the best plating method using impedance data analysis.  相似文献   
993.
Multiferroic BiFeO3 and Cr-doped (0.90)BiFe1?x Cr x O3–(0.10)BaTiO3 (x=0.00, 0.03, and 0.05) nanocomposites were prepared by sol–gel method. Optimum calcination and sintering strategies for obtaining pure perovskite phase have been determined. X-ray diffraction and transmission electron microscope (TEM) were used for the structural and particle size analysis, whereas LCR and SQUID magnetometer was used for dielectric and magnetic measurements. TEM measurements show that the average particle sizes of all the samples were ~19 nm. The dielectric constant was found to be increased twofold in low frequency region with the Cr-doping for x=0.05 in (0.90)BiFe1?x Cr x O3–(0.10)BaTiO3. The hysteresis curve (MH) exhibits ferromagnetic nature for all the samples (x=0.0, 0.03, and 0.05) and the spontaneous magnetization at room temperature was found to be 0.63 emu/gm in pure BiFeO3, which increased to 0.99 emu/gm for x=0.05. Zero-field-cooled (ZFC) and field-cooled (FC) magnetization curves show large discrepancy suggesting spin glass behavior.  相似文献   
994.
This paper projects the future of information technology within the context of the business and social environment in the mid 21st century. Some time in the next two decades we will enter our fourth industrial era, fueled by evolution in power, genetics, space exploration and information technologies. Unlike other industrial revolutions, this will be attended by widespread consolidations in industries as diverse as utility, retail, pharmaceuticals as well as the government. The trade wing of the UN, the United Nations Trade Organization (UNTO) is established to deal with global issues. The UNTO passes a number of resolutions including # 1/10 which deals with a uniform system of personal identification for all individuals. Due to free trade facilitated by electronic bureaucracies and global transportation grids, GNP growth rates triple. However, the consolidations will lead to the disappearance of clerical, administrative and management employees, leaving only the top management and highly skilled professionals. These changes will result in companies outsourcing all their routine processing to transaction and data centres. Employees will work from well equipped IT centres. The internet is in its third incarnation and is supported by a comprehensive web intelligence to answer all possible questions. Other technological changes include Terahertz computers, Personal identification Devices (PID), AI chips and hierarchical databases with relational interfaces. The cornucopia resulting from progress will lead to a more enlightened society. However, the stress of change will result in an increased degree of philosophical inquiry.  相似文献   
995.
Novel nanocomposite membrane based on polyurethane incorporated with garlic was fabricated using electrospinning technique for wound healing applications. Morphological analysis indicated that the incorporation of garlic into the polyurethane (PU) matrix resulted in reduction of fiber diameter and pore size compared to the pristine PU. Infrared analysis revealed the possible interaction of garlic with the PU through hydrogen bond formation. The contact angle studies and roughness measurements revealed the improved wettability and increased surface roughness of the fabricated composite compared to the pristine PU. The blood compatibility assay revealed the faster blood clotting time for the fabricated nanocomposites than the pristine PU. Furthermore, the fabricated nanocomposites showed less hemolytic index compared to the pristine PU suggesting their safety to red blood cells. Hence, with those advanced qualities PU blended with grapes may serve as a valuable candidate for wound dressing applications.  相似文献   
996.
The bipolar plate is one of the most imperative components of proton exchange membrane fuel cells (PEMFC) which consumes up to 80% of weight and near about 50% of the total cost of the cell. Development of cost‐effective composite bipolar plate with high electrical conductivity and high mechanical strength is both technically and economically demanding. In this paper, a low‐cost advanced composite bipolar plate is developed by bulk moulding compression (BMC) technique. It is clear from the experiments that by increasing the matrix volume fraction, bulk density and electrical conductivity of a composite bipolar plate decrease but shore hardness increases. Test results clearly show that best overall properties are achieved when a constant volume fraction of polymer matrix and natural graphite is reinforced with synthetic graphite, carbon black and carbon fibre. This bipolar plate was found to have high conductivity, less porosity and high mechanical strength. The IV characteristics in single cell test exhibited more uniform power density at both higher and lower current densities  相似文献   
997.
The objective of this paper is to evolve simple and effective methods for the economic load dispatch (ELD) problem with security constraints in thermal units, which are capable of obtaining economic scheduling for utility system. In the proposed improved particle swarm optimization (IPSO) method, a new velocity strategy equation is formulated suitable for a large scale system and the features of constriction factor approach (CFA) are also incorporated into the proposed approach. The CFA generates higher quality solutions than the conventional PSO approach. The proposed approach takes security constraints such as line flow constraints and bus voltage limits into account. In this paper, two different systems IEEE-14 bus and 66-bus Indian utility system have been considered for investigations and the results clearly show that the proposed IPSO method is very competent in solving ELD problem in comparison with other existing methods.  相似文献   
998.
Hydrothermally stable Al-MCM-48 with variety of Si/Al ratios and Al-MCM-41 with tunable pore sizes were successfully obtained from pre-heated aluminosilicate gel precursor. They showed the higher acid strength and hydrothermal stability comparing with conventional ones. Thus, this synthetic strategy offers a straightforward and convenient access to mesoporous aluminosilicates with zeolite-like acidity and stability.  相似文献   
999.
1000.
A series of new imidazolium-based oligomers with different length of a poly(ethylene glycol) moiety as a linker were synthesized and studied as electrolytes for dye-sensitized solar cell (DSSC). These oligomeric molecules are expected to have an intra- or inter-molecular hydrogen bonding interaction through its urethane and urea bonds. They can be used to prepare the liquid-type electrolytes for DSSC by dissolving them into conventional solvent system or to develop solvent-free electrolytes by incorporating an extra redox mediator and other functional materials together as additives. It was found that these oligomers could replace the cationic component of the conventional electrolytes and became the source of redox species when iodine is added. The photocurrent-voltage characteristics of DSSCs with the electrolytes containing these oligomers demonstrated that they can successfully replace the conventional ionic liquid-type electrolytes such as 1-methyl-3-propyl imidazolium iodide (PMII) in 3-methoxypropionitrile (MPN) if the length of the linker is optimized.  相似文献   
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