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排序方式: 共有317条查询结果,搜索用时 15 毫秒
51.
I Kabir MM Rahman R Haider RN Mazumder MA Khaled D Mahalanabis 《Canadian Metallurgical Quarterly》1998,128(10):1688-1691
The impact of dietary supplementation on catch-up growth was evaluated in 69 malnourished children ages 24-60 mo after recovery from shigellosis. They were fed either a high-protein (HP) diet with 15% of energy as protein, or a standard-protein (SP) diet with 7.5% energy as protein, for 3 wk in a metabolic study ward. Children were followed up bi-weekly for 6 mo by trained health assistants when anthropometric measurements and information of any illness were collected. Thirty-one children in the HP group and 28 children in the SP group completed 6-mo follow-up. The increase in height (mean +/- SD) was 5.3 +/- 1.0 cm vs. 4.1 +/- 1.1 cm for HP and SP groups, respectively (P < 0.001), whereas increase in body weight was 1.39 +/- 0.58 and 1.29 +/- 0.72 kg for children fed HP and SP, respectively (P = 0.59). The proportion of children who were severely stunted (< -2 SD height-for-age) decreased from 45 to 29% in the HP group compared to 50 to 46% in the SP group (P < 0.05) at 6-mo follow-up. The number of diarrheal episodes per child tended to be lower in the HP vs. SP than in the SP group (1.9 vs. 2.3, P = 0.41). These results demonstrate that feeding an HP diet to the malnourished children during recovery from shigellosis enhanced linear growth with a modest reduction in diarrheal morbidity during the 6-mo follow-up period. 相似文献
52.
53.
J. Singh Cm. Wayman J. Mazumder S. Lele S. Ranganathan 《Metallurgical and Materials Transactions A》1988,19(7):1703-1709
The microstructural evolution on aging a Co-3 wt pct Ti-2 wt pct Nb alloy has been followed by transmission electron microscopy
and diffraction to show that the solid solution decomposed by the spinodal mode. The strengthening observed has been correlated
with the differences in lattice parameters of the coexisting phases. The several stages of coarsening have been documented
to yield information about their kinetics and morphological changes.
Formerly Visiting Assistant Professor, Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign,
1206 West Green Street, Urbana, IL 61801, is with . 相似文献
54.
Hyungson Ki Jyoti Mazumder Pravansu S. Mohanty 《Metallurgical and Materials Transactions A》2002,33(6):1817-1830
A three-dimensional laser-keyhole welding model is developed, featuring the self-consistent evolution of the liquid/vapor
(L/V) interface together with full simulation of fluid flow and heat transfer. Important interfacial phenomena, such as free
surface evolution, evaporation, kinetic Knudsen layer, homogeneous boiling, and multiple reflections, are considered and applied
to the model. The level set approach is adopted to incorporate the L/V interface boundary conditions in the Navier-Stokes
equation and energy equation. Both thermocapillary force and recoil pressure, which are the major driving forces for the melt
flow, are incorporated in the formulation. For melting and solidification processes at the solid/liquid (S/L) interface, the
mixture continuum model has been employed. The article consists of two parts. This article (Part I) presents the model formulation
and discusses the effects of evaporation, free surface evolution, and multiple reflections on a steady molten pool to demonstrate
the relevance of these interfacial phenomena. The results of the full keyhole simulation and the experimental verification
will be provided in the companion article (Part II). 相似文献
55.
Multi-objective optimization with artificial weed colonies 总被引:2,自引:0,他引:2
Invasive Weed Optimization (IWO) was recently proposed as a simple but powerful metaheuristic algorithm for real parameter optimization. IWO draws inspiration from the ecological process of weeds colonization and distribution and is capable of solving general multi-dimensional, linear and nonlinear optimization problems with appreciable efficiency. This article extends the basic IWO for tackling multi-objective optimization problems that aim at achieving two or more objectives (very often conflicting) simultaneously. The concept of fuzzy dominance has been used to sort the promising candidate solutions at each iteration. The new algorithm has been shown to be statistically significantly better than some state of the art existing evolutionary multi-objective algorithms, namely NSGAIILS, DECMOSA-SQP, MOEP, Clustering MOEA, GDE3, and MOEADGM on a 12-function test-suite (including both unconstrained and constrained problems) from the IEEE CEC (Congress on Evolutionary Computation) 2009 competition and special session on multi-objective optimization algorithms. The following performance metrics were considered: IGD, Spacing, and Minimum Spacing. Our experimental results suggest that IWO holds immense promise to appear as an efficient metaheuristic for multi-objective optimization. 相似文献
56.
Microsystem Technologies - This article presents a circuit level representation from gated diode which is developed from Thymine single wall nanotube-like structure using density functional theory... 相似文献
57.
A study of the effects of the breaker-card-cylinder speed and delivery-roller speed on jute-yarn properties is reported. Though machine makers recommend a cylinder speed of 200 rev/min, a speed of 150 rev/min is shown to give a better yarn, even when the production is kept at the same level. Finer fibres absorb more power and yield yarn of higher strength. The strength realization of the fibre is also higher at a lower cylinder speed. 相似文献
58.
59.
Coatings for superalloys for extended service in atmospheres at high temperature are of great interest at present. The addition
of reactive elements (RE’s) such as Hf to these coatings has a pronounced effect on their high-temperature oxidation resistance.
A laser-cladding technique was used to produce Ni-Al-Cr-Hf alloys with an extended solid solution of Hf in a nearstoichiometric
Ni3Al matrix. A 10 kW CO2 laser with mixed powder feed was used for the cladding process. Scanning electron microscope (SEM), transmission electron
microscope (TEM), and scanning transmission electron microscope (STEM) were employed for studies of microstructural evolution
of alloys produced during the laser-cladding process. Microstructural studies reveal the formation of dendrites with a solid
solubility of about 11 to 14 wt pct Hf and also a eutectic structure. Convergent-beam techniques and X-ray spectroscopy have
been applied to characterize the phases formed during the cladding process. 相似文献
60.
Carl R. Ribaudo Jyoti Mazumder Dennis W. Hetzner 《Metallurgical and Materials Transactions B》1992,23(4):513-522
A new mechanism for the improved retention of alumina scales formed on laser-clad NiAICrHf alloys has been observed. Laser
cladding is the process where fine metal powders are rapidly melted and fused to a solid substrate using a CO2 laser. The
effects of laser cladding upon scale retention on NiAICrHf alloys after cyclic and isothermal exposure to air were investigated
using thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The calculated compressive
stress in the scale due to constrained cooling exceeded the probable compressive strength of alumina. Additions of up to ≈
2.5 wt pct Hf increasingly promote retention of scales grown at 1200 °C, with laser-clad samples of ≈ 2.5 wt pct Hf alloy
retaining almost completely intact scales. The improvement in scale retention is due to improved toughness in scales containing
hafnia polycrystallites, possiblyvia microcracking initiated by anisotropic thermal contraction of the hafnia. Laser cladding the 2.5 wt pct Hf alloy provides
a large concentration of ~ 1 μm Hf-rich particles that are precursors of the hafnia in the scale as well as a finer dendrite
spacing that reduces the mean free distance between particles.
Formerly Graduate Research Assistant, Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign 相似文献