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101.
102.
In this research work, electrical conductivity of a novel cast 6351 Al–Al4SiC4 composite has been studied for varying Al4SiC4 particle content (2–7 vol%). Analytical models were developed on the basis of free electron theory and local resistance approach in order to predict electrical conductivity of metal matrix composites. The electrical conductivity of cast 6351 Al–Al4SiC4 composite was found to decrease with increasing Al4SiC4 content. Overprediction of results and more % deviation of the predicted electrical conductivity from experimental value were observed for local-resistance-approach-based model. However, the model developed on the basis of electron theory considering scattering of electrons at particle–matrix interface accurately predicted the experimental electrical conductivity data. 相似文献
103.
104.
G. Mohan Kumar P. Ilanchezhiyan Jin Kawakita Jinsub Park R. Jayavel 《Journal of Materials Science: Materials in Electronics》2013,24(8):2989-2994
One-dimensional Mn doped ZnO nanocrystallites were synthesized through a facile low temperature surfactant free chemical route. The crystallite structure and morphological evolution of the particles were revealed to be of wurtzite phase and rod like structures from the X-ray diffraction and transmission electron microscopic analysis, respectively. Using Raman spectroscopy the role of oxygen related defects and phase purity in the Mn substituted ZnO systems were studied systematically. A significant suppression in the sub-band edge emission was visualized in the room temperature emission spectra of the Mn doped systems. The intensity ratio in between the near-band edge and defect-level emissions was observed to increase, signifying the reduction in oxygen related defects and revealing their influence on the crystallinity on the Mn substituted ZnO species. These variations were correlated with the increasing number of Mn ions in the host lattice, which results with their passivating action on the surface defects. 相似文献
105.
Nilrudra Mandal H. Roy B. Mondal N. C. Murmu S. K. Mukhopadhyay 《Journal of Materials Engineering and Performance》2012,21(1):17-24
In the light of attractive wear characteristics as well as high strength to weight ratio, extensive research on Al-based Metal
Matrix Composite (MMC) have been carried out globally in the last two decades. However, very limited research has been pursued
on tribological behavior of Al-based MMC under combined action of rolling and sliding. This study investigates the wear behavior
of 6061 Al-alloy/SiC with 10 vol.% SiCp against hardened and tempered AISI 4340 steel under combined rolling-sliding conditions. 23 factorial design of experiments have been carried out to see the effect of few parameters, i.e., contact stress, speed and
duration with respect to wear. The interaction effect has also been studied by 3D graphical contours. A mathematical model
is developed using regression analysis technique for prediction of wear behavior of the MMC and adequacy of the model has
been validated using analysis of variance (ANOVA) techniques. Finally, the optimization of parameter has also been done using
Design Expert software. The results have shown that Response Surface Methodology (RSM) is an effective tool for prediction
of wear behavior under combined sliding and rolling action. It is also found that the wear of MMC is much lower than hardened;
tempered AISI 4340 steel and rolling speed has the maximum influence in wear of both materials under investigation. 相似文献
106.
P. Ilanchezhiyan C. Siva T. W. Kang G. Mohan Kumar 《Journal of Materials Science: Materials in Electronics》2016,27(6):5557-5562
Solution processed wide band gap dielectrics have nowadays started to receive renewed interest for practical application in semiconductor electronics. In this regard, undoped and gadolinium (Gd) doped zirconia (ZrO2) nanocrystallites were colloidally processed and their potential for dielectric applications has been demonstrated. X-ray diffraction measurements revealed the effective crystallization of nanostructures and the successful substitution of Gd ions into the cubic ZrO2 matrix. The particulate-like characteristics of undoped and Gd doped ZrO2 nanostructures were examined through the electron microscopes, which hardly revealed any difference among them. The optical band gap of ZrO2 nanostructures was determined to be around 4.64–4.80 eV from the absorbance measurements. The potential of Gd doped ZrO2 nanostructures for dielectric functions were evaluated through electrochemical impedance spectroscopic measurements. The improved capacitance values estimated from the Nyquist plots suggests the potential of the investigated materials for low power and low voltage electronic applications. 相似文献
107.
We consider a Lorentzian manifold M which is globally hyperbolic. We define a metric on C(p, q), the set of all equivalence classes of causal curves connecting two causally related points p and q. We show that C(p, q) is a complete metric space with the metric thus defined. Here, by completeness we mean that every Cauchy sequence (a sequence with a tendency to converge) in C(p, q) finds a point in it to converge. We also give an example to show that the result does not hold in general when the spacetime is not globally hyperbolic. The work is in line with research on causality in relativistic spacetimes. 相似文献
108.
V. Srinivas Ch. Kodanda Rama Rao N. Mohan Rao 《Tribology - Materials, Surfaces & Interfaces》2018,12(2):107-114
This paper studies the effect of surface modification of multiwall carbon nanotubes (MWCNTs) prior to dispersion in engine oil to improve the tribological properties. The MWCNTs are stabilised in the lubricant with two different surfactants cetrimonium bromide (CTAB) and sorbitan monooleate (SPAN 80) and the effect of surfactants on the tribological properties has been studied. Pristine and surface modified MWCNTs in weight per cent range of 0·5% are dispersed in CI4 plus diesel engine oil. The foaming tendency and other physico-chemical properties of test lubricant have been studied to investigate the effect of nano materials and surfactants. The anti-wear and anti-friction properties are tested on a four ball wear tester and the comparison is made to assess the relative performance of pristine MWCNTs over surface modified MWCNTs. A strong influence of the surface modification technique is found on lubricating and physico-chemical properties. Both CTAB and SPAN 80 could keep the MWCNTs stable in the lubricant without compromising the foaming tendency of lubricant and other physico-chemical properties. The friction and wear characteristics of lubricants have improved with the dispersion of surface modified MWCNTs while there is no improvement in the properties of lubricant dispersed with pristine MWCNTs. 相似文献
109.
Wireless Personal Communications - Nowadays, Wireless Sensor Networks (WSNs) is enhancing for different applications. Simultaneously, energy consumption for processing the tasks in most of the... 相似文献
110.