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71.
A. Sivasankar Reddy P. Sreedhara Reddy S. Uthanna G. Mohan Rao 《Journal of Materials Science: Materials in Electronics》2006,17(8):615-620
Thin films of copper aluminum oxide (CuAlO2) were prepared on glass substrates by dc magnetron sputtering at a substrate temperature of 523 K under various oxygen partial
pressures in the range 1 × 10−4–3 × 10−3 mbar. The dependence of cathode potential on the oxygen partial pressure was explained in terms of oxidation of the sputtering
target. The influence of oxygen partial pressure on the structural, electrical and optical properties was systematically studied.
p-Type CuAlO2 films with polycrystalline nature, electrical resistivity of 3.1 Ω cm, Hall mobility of 13.1 cm2 V−1 s−1 and optical band gap of 3.54 eV were obtained at an oxygen partial pressure of 6 × 10−4 mbar. 相似文献
72.
Diglycidyl ether of bisphenol-A (DGEBA) epoxy resin system filled individually with organoclay (OC) and unmodified clay (UC) were synthesized by mechanical shear mixing with the addition of diamino-diphenylmethane (DDM) hardener. The unmodified clay used was Na+-Montmorillonite (MMT) and the organoclay was alkyl ammonium treated MMT clay. The reinforcement effect of OC and UC in the epoxy polymer on thermal, mechanical and vibration properties were studied. X-ray diffraction (XRD) and Transmission electron microscopy (TEM) were used to study the structure and morphology of nanocomposites. Curing study shows that the addition of OC in epoxy resin aids the polymerization by catalytic effect, and UC addition does not show any effect in the curing behavior of epoxy polymer. Thermogravimetry analysis (TGA) shows enhanced thermal stability for epoxy with OC fillers than that of epoxy with UC fillers. The epoxy with OC fillers shows considerable improvement on tensile and impact properties over pure epoxy polymer and epoxy with UC fillers. The improvement in tensile and impact properties of nanocomposites is supported with the fracture surface studies. Epoxy with OC fillers shows enhanced vibration characteristics than that of the pure epoxy polymer and epoxy with UC fillers. 相似文献
73.
L. J. Dhareshwar S. Chaurasia C. G. Murali N. K. Gupta B. K. Godwal 《Journal of Materials Science》2006,41(5):1623-1630
X-ray and ion emissions from high temperature plasmas from solid targets with different atomic numbers have been studied.
Plasma is generated using a high power Nd:Glass laser generating focused intensity in the range of 1012 to 1013 Watts/cm2 on targets. Plasma temperature is typically between 50 to 100 eV. X-ray emission scaling as a function of laser intensity
as well as ion velocity has been measured in these targets. Non-uniform plasma expansion and generation of fast ions are observed
for targets with higher atomic numbers. 相似文献
74.
Florence Yean Yng Ling C. William Ibbs Mohan M. Kumaraswamy 《Canadian Metallurgical Quarterly》2005,21(2):63-69
With China’s fast economic growth and entry into the World Trade Organization (WTO), more foreign architectural, engineering, and construction (AEC) firms are expected to venture into this huge and attractive market. This paper explores the important strategies to help foreign AEC firms clinch construction projects in China. Using a questionnaire survey approach complemented by in-depth interviews, it was found that firms need to pay more attention to the market and working conditions in China and to strengthen their own capabilities. To win projects in China, foreign AEC firms should also be able to offer project financing services. The findings are useful to foreign AEC firms because it may help them win projects in the Chinese construction industry. 相似文献
75.
N. D. V. N. S. Murali Krishna Ligy Philip 《Clean Technologies and Environmental Policy》2005,7(4):285-293
Nitrogen dioxide (NO2) removal efficiency of a biotrikling filter was evaluated under different operating conditions. Activated alumina (AA) was
used as the immobilization matrix for Thiobacillus denitrificans (T. denitrificans) in the biotrickling filter. Batch studies were conducted to find out the degradation kinetics of nitrate and nitrite for
a concentration range of 600–10,000 mg/L expressed as nitrogen. Nitrite exhibited maximum degradation rate followed by nitrate.
Electron acceptor in the form of NO2 gas showed least removal efficiency. Bio-kinetic parameters for T. denitrificans, by utilizing nitrate and nitrite as electron acceptors, were also evaluated. The μmax (Maximum specific growth rate) and YT (Yield coefficient) values for T. denitrificans in the presence of nitrate and nitrite were 1.03 h−1, 0.275 and 0.63 h−1, 0.1316 respectively. Column study was conducted to find the adsorption and desorption potential of activated alumina. The
adsorbed NO2 from AA could easily be desorbed using distilled water with an efficiency of 76±0.8%. Once fed batch studies were conducted
to evaluate the NO2 removal efficiency by a biotrickling filter. With an influent NO2 gas concentration of 2,735 ppm, the reactor could achieve a removal efficiency of 99% within 2 min from gas phase and within
96 h from the liquid phase, with an average biomass concentration of 200 mg/g of AA. The mechanism of NO2 gas removal in the biotrickling filter seems to be the dissolution of NO2 in water to form NO3−, conversion of NO3− to NO2
−, and finally to N2 gas. 相似文献
76.
Real-time three-dimensional tracking of people is an important requirement for a growing number of applications. In this
paper we describe two trackers; both of them use a network of video cameras for person tracking. These trackers are called
a rectilinear video array tracker (R-VAT) and an omnidirectional video array tracker (O-VAT), indicating the two different
ways of video capture. The specific objectives of this paper are twofold: (i) to present a systematic comparison of these
two trackers using an extensive series of experiments conducted in an `intelligent' room; (ii) to develop a real-time system
for tracking the head and face of a person, as an extension of the O-VAT approach. The comparative research indicates that
O-VAT is more robust to the number of people, less complex and runs faster, needs manual camera calibration, and the integrated
omnidirectional video network has better reconfigurability. The person head and face tracker study shows that such a system
can serve as a most effective input stage for face recognition and facial expression analysis modules. 相似文献
77.
Controller design and performance evaluation for deadlock avoidance in automated flexible manufacturing cells 总被引:2,自引:0,他引:2
In this paper, the design of a deadlock avoidance controller is described. The uncontrolled system is modeled using colored Petri nets. The system controller is based on a restrictive (not maximally permissive) deadlock avoidance policy to resolve deadlocks and control the real-time resource allocation decisions in the system. Performance evaluation of systems controlled by not maximally permissive algorithms is essential in determining the applicability and effectiveness of the control algorithms. The performance of the controlled system is compared with performance of optimal control policies to quantify the effects of the restrictiveness of the deadlock avoidance policy on system performance. 相似文献
78.
79.
Wang Z. Das S.K. Che H. Mohan Kumar 《Parallel and Distributed Systems, IEEE Transactions on》2004,15(11):983-995
In the literature, there exit two types of cache consistency maintenance algorithms for mobile computing environments: stateless and stateful. In a stateless approach, the server is unaware of the cache contents at a mobile user (MU). Even though stateless approaches employ simple database management schemes, they lack scalability and ability to support user disconnectedness and mobility. On the other hand, a stateful approach is scalable for large database systems at the cost of nontrivial overhead due to server database management. We propose a novel algorithm, called Scalable Asynchronous Cache Consistency Scheme (SACCS), which inherits the positive features of both stateless and stateful approaches. SACCS provides a weak cache consistency for unreliable communication (e.g., wireless mobile) environments with small stale cache hit probability. It is also a highly scalable algorithm with minimum database management overhead. The properties are accomplished through the use of flag bits at the server cache (SC) and MU cache (MUC), an identifier (ID) in MUC for each entry after its invalidation, and estimated time-to-live (TTL) for each cached entry, as well as rendering of all valid entries of MUC to uncertain state when an MU wakes up. The stale cache hit probability is analyzed and also simulated under the Rayleigh fading model of error-prone wireless channels. Comprehensive simulation results show that the performance of SACCS is superior to those of other existing stateful and stateless algorithms in both single and multicell mobile environments. 相似文献
80.
In order to produce energy-efficient material for tribological applications, Al–Fe inter-metallic composites have been produced by liquid metallurgy route. Iron content of the composites varies from 1.67 to 11.2 wt.%. These composites have been tested for their wear properties at different parameters. Debris and wear tracks have been studied in detail to see the surface effects during dry sliding and have been correlated to wear properties. Observations show that low loads and sliding velocities are dominated by oxidative debris and largely covered wear track surface with smooth oxide layer is observed. Whereas metallic debris dominates at higher loads and sliding velocities and highly deformed wear track surface with deep grooves and gross delamination were observed. Further, wear rate is seen to increase continuously with load whereas with sliding velocity it attains a minima after initial decrease and then increases continuously. Low solubility of iron supports the formation of FeAl3 and an increase in hardness from 95 to 179 VHN continuously improves the wear resistance with increase in percentage iron. 相似文献