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排序方式: 共有717条查询结果,搜索用时 15 毫秒
31.
Nanda De Abhijit Sengupta Subir Bandyopadhyay Pradip K. Srimani 《Information Sciences》1980,22(2):131-138
A new necessary and sufficient condition for t-diagnosability of a system is proposed. It is shown that the new scheme is computationally more efficient than the existing one for checking the diagnosability of a system. 相似文献
32.
P. J. Sunder C. V. Ramakrishnan S. Sengupta 《International journal for numerical methods in engineering》1983,19(8):1183-1192
The results of the finite element analysis of 3-ply laminated conical shells with light core for linear panel flutter are presented and certain advantages of such shells discussed. 相似文献
33.
I. N. Sengupta 《Scientometrics》1989,17(3-4):289-300
Ranking lists of periodicals in different scientific disciplines are generally based on the total number of citations derived from a group of source journals with equal weightage given to all citations irrespective of chronology. As a result, in all these ranking lists, the position occupied by the post-war journals, may not be an accurate index of their demand or usefulness to research workers in the concerned field. This may happen because the quantum of published literature in the new journals is limited by the period for which they have been in existence, which is in many cases less than 20 years. Moreover, many of the post-war journals appearing in all these recent ranking lists have started publication even after 1960s, and their enumerated citations cover in fact a variable period of less than 20 years unlike in the case of pre-war journals. To avoid such discriminating against new journals which necessarily have fewer citation credits Sengupta suggested earlier an off-setting weightage formula which has been applied in this paper to rerank microbiology periodicals. A revised ranking list in the field of microbiology has been recommended in preference to the earlier one compiled by Sengupta. Results and findings, after application of the weightage formula, have been presented and discussed in this paper. 相似文献
34.
S. Sengupta H. Soda A. McLean J. W. Rutter 《Metallurgical and Materials Transactions A》2000,31(1):239-248
A ternary eutectic alloy with a composition of 57.2 pct Bi, 24.8 pct In, and 18 pct Sn was continuously cast into wire of
2 mm diameter with casting speeds of 14 and 79 mm min−1 using the Ohno Continuous Casting (OCC) process. The microstructures obtained were compared with those of statically cast
specimens. Extensive segregation of massive Bi blocks, Bi complex structures, and tinrich dendrites was found in specimens
that were statically cast. Decomposition of γSn by a eutectoid reaction was confirmed based on microstructural evidence. Ternary eutectic alloy with a cooling rate of
approximately 1 °C min−1 formed a double binary eutectic. The double binary eutectic consisted of regions of BiIn and decomposed γSn in the form of a dendrite cell structure and regions of Bi and decomposed γSn in the form of a complex-regular cell. The Bi complex-regular cells, which are a ternary eutectic constituent, existed
either along the boundaries of the BiIn-decomposed γSn dendrite cells or at the front of elongated dendrite cell structures. In the continuously cast wires, primary Sn dendrites
coupled with a small Bi phase were uniformly distributed within the Bi-In alloy matrix. Neither massive Bi phase, Bi complex-regular
cells, nor BiIn eutectic dendrite cells were observed, resulting in a more uniform microstructure in contrast to the heavily
segregated structures of the statically cast specimens. 相似文献
35.
D. Bahadur D. Chakravorty D. Chattopadhyaya S. Datta S. K. Khan S. Mitra S. Ram D. Roy K. Sengupta 《Journal of Materials Science》1986,21(8):2793-2797
The effect of bismuth, silver oxide and palladium on the crystallization of yttrium iron garnet in Na2O-SiO2-Y2O3-Fe2O3 glass-ceramics has been investigated by X-ray diffraction thermal analysis, magnetic measurements and optical microscopy. It is found that the magnetic properties of these glass-ceramics can be altered significantly by a change in the nucleating agents and the heat treatment schedule. This behaviour is explained on the basis of the microstructure and the volume fraction of the different magnetic phases crystallized within the glasses. 相似文献
36.
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
37.
V. Kain P. Sengupta P. K. De S. Banerjee 《Metallurgical and Materials Transactions A》2005,36(5):1075-1084
This article describes the corrosion behavior of special austenitic alloys for waste management applications. The special
stainless steels have controlled levels of alloying and impurity elements and inclusion levels. It is shown that “active”
inclusions and segregation of chromium along flow lines accelerated IGC of nonsensitized stainless steels. Concentration of
Cr+6 ions in the grooves of dissolved inclusions increased the potential to the transpassive region of the material, leading to
accelerated attack. It is shown that a combination of cold working and controlled solution annealing resulted in a microstructure
that resisted corrosion even after a sensitization heat treatment. This imparted extra resistance to corrosion by increasing
the fraction of “random” grain boundaries above a threshold value. Randomization of grain boundaries made the stainless steels
resistant to sensitization, IGC, and intergranular stress corrosion cracking (IGSCC) in even hot chloride environments. The
increased corrosion resistance has been attributed to connectivity of random grain boundaries. The reaction mechanism between
the molten glass and the material for process pot, alloy 690, during the vitrification process has been shown to result in
depletion of chromium from the reacting surfaces. A comparison is drawn between the electrochemical behavior of alloys 33
and 22 in 1 M HCl at 65 °C. It is shown that a secondary phase formed during welding of alloy 33 impaired corrosion properties
in the HCl environment.
This article is based on a presentation made in the symposium “Effect of Processing on Materials Properties for Nuclear Waste
Disposition,” November 10–11, 2003, at the TMS Fall meeting in Chicago, Illinois, under the joint auspices of the TMS Corrosion
and Environmental Effects and Nuclear Materials Committees. 相似文献
38.
Two-dimensional incompressible Navier-Stokes equations are solved using SIMPLER method in the intrinsic curvilinear coordinates
system to study the unsteady viscous flow physics over two-dimensional ellipses Unsteady viscous flows over various thickness-to-chord
ratios of 06, 08, 10, and 1 2 elliptic cylinders are simulated at different Reynolds numbers of 200, 400, and 1,000 This study
is focused on the understanding the effects of Reynolds number and elliptic cylinder thickness on the drag and lift forces
The present numerical solutions are compared with available experimental and numerical results and show a good agicement Through
this study, it is observed that the Reynolds number and the cylinder thickness affect significantly the frequencies of the
force oscillations as well as the mean values and the amplitudes of the drag and lift forces 相似文献
39.
Theoretical expressions for the currents excited on the top and bottom surfaces of a coaxial-probe-fed patch antenna are derived. Exact expressions for the far-zone field in terms of the total current on the patch are found. The analysis is specialized to a two-dimensional case. Detailed results for current, far-zone fields, and radiating-aperture admittance have been computed for this two-dimensional antenna model using the conjugate-gradient-fast Fourier transform (CG-FFT) technique. For a thick-substrate antenna it is found that the upper surface current on the patch is significant. Under this condition the traditional approximation of the total current by the bottom surface current alone may be in considerable error 相似文献
40.