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61.
Samarium cobalt films were prepared on silicon substrates with and without a chromium buffer layer at room temperature and 600°C using direct current unbalanced magnetron sputtering. For obtaining ideal magnetic properties, the films should be free from impurities, such as O, Al and others. Rutherford backscattering spectrometry and heavy ion elastic recoil detection analysis were used to determine the composition and film thickness and to monitor the light element contamination across film thickness. X-ray diffractometer and superconducting quantum interference device were employed to characterize the structure and magnetic properties of the films, respectively. The results obtained led to an improved design of the ground shield and the use of a sorption pump to effectively minimize aluminium and oxygen concentration in the films, respectively. 相似文献
62.
63.
Aditya Kanade Amitabha Sanyal Uday Khedker 《Electronic Notes in Theoretical Computer Science》2007,176(3):79
A compiler optimization is sound if the optimized program that it produces is semantically equivalent to the input program. The proofs of semantic equivalence are usually tedious. To reduce the efforts required, we identify a set of common transformation primitives that can be composed sequentially to obtain specifications of optimizing transformations. We also identify the conditions under which the transformation primitives preserve semantics and prove their sufficiency. Consequently, proving the soundness of an optimization reduces to showing that the soundness conditions of the underlying transformation primitives are satisfied.The program analysis required for optimization is defined over the input program whereas the soundness conditions of a transformation primitive need to be shown on the version of the program on which it is applied. We express both in a temporal logic. We also develop a logic called temporal transformation logic to correlate temporal properties over a program (seen as a Kripke structure) and its transformation.An interesting possibility created by this approach is a novel scheme for validating optimizer implementations. An optimizer can be instrumented to generate a trace of its transformations in terms of the transformation primitives. Conformance of the trace with the optimizer can be checked through simulation. If soundness conditions of the underlying primitives are satisfied by the trace then it preserves semantics. 相似文献
64.
Aditya M. Vora 《Journal of Superconductivity and Novel Magnetism》2007,20(5):387-392
The theoretical study of the superconducting state parameters (SSP) viz. electron–phonon coupling strength λ, Coulomb pseudopotential μ
*, transition temperature T
C
, isotope effect exponent α and effective interaction strength N
O
V of 5d-transition metals based binary alloys have been made extensively in the present work using a model potential for the
first time. A considerable influence of various exchange and correlation functions on λ and μ
* is found from the present study. The present results of the SSP are found in qualitative agreement with the available experimental
data wherever it exists. 相似文献
65.
Ankur Sood Varun Arora Jyoti Shah R.K. Kotnala 《Journal of Experimental Nanoscience》2016,11(5):370-382
The current article reports on providing surface modification of magnetic nanoparticles with gold to provide stability against aggregation. Gold-coated magnetite nanoparticles were synthesised to combine both magnetic as well as surface plasma resonance (SPR) properties in a single moiety. The nanocomposites were produced by reduction (using ascorbic acid) of gold chloride on to the surface of iron oxide nanoparticles. Ascorbic acid not only acts as a reducing agent, but also the oxidised form of ascorbic acid i.e. Dehydro-ascorbic acid acts as a capping agent to impart stability to as synthesised gold-coated iron oxide nanocomposites. The synthesised nanocomposite was monodispersed with a mean particle size of around 16 nm and polydispersity index of 0.190. X-ray diffraction analysis confirms presence of gold on the surface of magnetite nanoparticles. The synthesised nanocomposites had a total organic content of around 3.2% w/w and also showed a shifted SPR peak at 546 nm as compared to gold nanoparticles (528 nm). Both uncoated and gold-coated magnetite exhibited superparamagnetic behaviour at room temperature. Upon coating with gold shell, saturation magnetisation of iron oxide nanoparticles decreases from 42.806 to 3.54 emu/gram. 相似文献
66.
Aditya Tulsyan Biao Huang R. Bhushan Gopaluni J. Fraser Forbes 《Journal of Process Control》2013,23(4):516-526
On-line estimation plays an important role in process control and monitoring. Obtaining a theoretical solution to the simultaneous state-parameter estimation problem for non-linear stochastic systems involves solving complex multi-dimensional integrals that are not amenable to analytical solution. While basic sequential Monte-Carlo (SMC) or particle filtering (PF) algorithms for simultaneous estimation exist, it is well recognized that there is a need for making these on-line algorithms non-degenerate, fast and applicable to processes with missing measurements. To overcome the deficiencies in traditional algorithms, this work proposes a Bayesian approach to on-line state and parameter estimation. Its extension to handle missing data in real-time is also provided. The simultaneous estimation is performed by filtering an extended vector of states and parameters using an adaptive sequential-importance-resampling (SIR) filter with a kernel density estimation method. The approach uses an on-line optimization algorithm based on Kullback–Leibler (KL) divergence to allow adaptation of the SIR filter for combined state-parameter estimation. An optimal tuning rule to control the width of the kernel and the variance of the artificial noise added to the parameters is also proposed. The approach is illustrated through numerical examples. 相似文献
67.
68.
Aditya Putranto 《Drying Technology》2013,31(14):1658-1665
For improving product quality and minimizing energy consumption during drying, intermittent drying is often recommended. The mathematical models that are used to describe intermittent drying are usually transport phenomena based, complex models. In this study, the lumped reaction engineering approach (L-REA) is implemented to model wood drying under rapid periodically changed drying air temperature and humidity with high number of cycles of intermittency. The equilibrium activation energy (ΔE v,b ), an important parameter for REA approach, is evaluated according to the corresponding drying air temperature and humidity in each drying section. The results of modeling suggest the L-REA works well with the experimental data. The simplicity of the L-REA is obvious and is hoped to be used in an industrial setting more readily. The L-REA can be used for sustainable processing in industries to assist in energy audit and management. 相似文献
69.
Anil Kumar Mandeep Kaur Rajeev Kumar Pinaki Ranjan Sengupta Vasantha Raman Gopal Bhatia Kedar Nath Sood 《Journal of Materials Science》2010,45(5):1393-1400
Carbon–copper composites with varying copper to carbon ratio of 0.66–1.5 (by weight) were developed from coal-tar-pitch-derived
green coke (as such or modified with natural graphite) as carbon source and electrolytic grade copper powder at different
heat treatment temperatures (HTTs) of 1000–1400 °C. The physical, mechanical, and electrical properties differ depending upon
the HTT and also on copper to carbon ratio (Cu/C). The composites prepared at HTT of 1100 °C having Cu/C ratio of 0.66 and
0.9 exhibited a high bending strength of 150 and 140 MPa, bulk density of 2.63 and 2.81 gm/cm3, electrical resistivity of 1.6 and 0.96 m Ω cm and shore hardness of 88 and 84, respectively, in spite of well-known inadequate
wettability between copper and carbon. Increasing the temperature from 1100 °C for processing of the composites deteriorated
the properties mainly due to the loss of copper through melting above 1100 °C as revealed by X-ray, scanning electron microscopy,
thermal analysis and EDAX studies. 相似文献
70.
Jianjun Gao Choi Look Law Hong Wang Sheel Aditya 《Journal of Infrared, Millimeter and Terahertz Waves》2002,23(11):1611-1626
An improved equivalent circuit model under pinchoff condition for extracting parasitic model parameters for Double Heterojunction δ-doped PHEMTs is presented. Good prediction for S parameters and noise performance are obtained up to 40GHz. A modified parameter extraction technique based on this new model was use to determine a PHEMT equivalent circuit model. Signification improvements of the accuracy of S parameters are obtained by using the new pinchoff model. 相似文献