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91.
G. Hema Chandra C. Udayakumar N. Padhy S. Uthanna 《Materials Science in Semiconductor Processing》2010,13(4):288-294
CuIn0.75Al0.25Se2 thin films prepared onto glass substrates at TS=573 K were single phase, nearly stoichiometric and polycrystalline with a strong (1 1 1) preferred orientation showing sphalerite structure. The results of X-ray diffraction and electron diffraction studies are compared, interpreted and correlated with micro-Raman spectra. The optical absorption studies indicated a direct band gap of 1.16 eV with high absorption coefficient (>104 cm?1) near the fundamental absorption edge. 相似文献
92.
Medium carbon steel (AISI 1040) was one of the candidate materials for rock bolts to reinforce the borehole liners and emplacement
drifts of the high-level nuclear waste repository in Yucca Mountain. The corrosion performance of this structural steel was
investigated by techniques such as linear polarization, electrochemical impedance spectroscopy (EIS), and laboratory immersion
tests in simulated ground waters. The corrosion rates of the steel were measured for the temperatures in the range from 25
°C to 85 °C, for the ionic concentrations of 1 time (1×), 10 times (10×), and a hundred times (100×) ground water concentration.
The steel corroded uniformly at penetration rates of 35 to 200 μm/year in the deaerated waters, and at 200 to 1000 μm/year in the aerated waters. Increasing temperatures in the deaerated waters increased the corrosion rate of the steel. However,
increasing ionic concentrations influenced the corrosion rate only slightly. In the aerated 1×and 10×waters, increasing temperatures
increased the rates of the steel significantly. In the aerated 100×waters, the corrosion rate increased from 25 °C to 45 °C
and decreased at higher temperatures (65 °C and up) due to the formation of oxide/hydroxide films and salt scales on the surface
of the steel specimen. The steel suffered pitting corrosion in the both deaerated and aerated hot ground water environments
after anodic polarization.
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
93.
Silicon - A tunable terahertz (THz) dielectric resonator (DR) antenna (DRA) with circular polarization operating with multiple higher order modes is numerically studied and implemented. A... 相似文献
94.
Mass transfer across gas and liquid boundary layers into the core of drops with liquid phase first order chemical reaction has been analyzed for spherical drops in the Reynolds number range of 50 < Reg < 400. The realistic and computationally efficient simulation of this gas absorption system is applicable in a variety of engineering fields including gas-liquid mass transfer in drops and sprays. The present paper deals with the fluid mechanics and mass transfer with chemical reaction of a single drop. In computer experiments good predictive agreement has been achieved with measured data. The theoretical results were generalized to show the influence of three major system parameters: Peclet number Peg or Pel Damköhler number Da and the distribution coefficient at the gas-liquid interface, M, on mass transfer and to demonstrate the importance of coupled gas- and liquid-phase resistances to gas absorption under practical conditions. 相似文献
95.
Jin-Seok Park David Nkurunziza Vikash Chandra Roy Truc Cong Ho Sung-Yeoul Kim Seung-Chan Lee Byung-Soo Chun 《International Journal of Food Science & Technology》2022,57(8):5090-5101
This study investigated the effect of sequential extraction techniques and pretreatment methods in enhancing the recovery of high-value products from spent coffee ground. Supercritical carbon dioxide (SC-CO2) deoiling was performed to recover non-polar lipids, and subcritical water (SCW) hydrolysis of deoiled spent coffee ground (SCG) was conducted involving pretreatment with ultrasound (US-SCG), and sample particle size reduction (PS-SCG). SCW temperature, solid/liquid mixing ratio, constant pressure and residence time were studied for their effect on extracting reducing sugars (RS), total phenolic content (TPC), total flavonoid content (TFC), 5-HMF, and furfural. Temperature increase enhanced hydrolysis efficiency and promoted RS dehydration into 5-HMF and furfural. At 180 °C and 40 mg/600 mL, TPC, TFC and RS values increased significantly with ultrasound pretreatment correlating with improved antioxidant activities by DPPH and ABTS assays. Highest amount of 5-HMF and furfural was obtained at 210°C (highest temperature studied) with 44.71 and 2.36 mg/100 g. Chlorogenic acid recovery was the highest in the non-deoiled SCG (15.07 mg/100 g), with no significant difference observed in PS-SCG, suggesting an increase due to its reduced particle size. The results of this study provide comprehensive knowledge on the combined effects of integrated engineering systems to boost the valorisation of SCGs into high-value products. 相似文献
96.
Subhash Chandra Ghosh Senthilkumar Muthaiah Yao Zhang Xiangya Xu Soon Hyeok Hong 《Advanced Synthesis \u0026amp; Catalysis》2009,351(16):2643-2649
Amides are synthesized directly from alcohols and amines in high yields using an in situ generated catalyst from easily available ruthenium complexes such as the (p‐cymene)ruthenium dichloride dimer, [Ru(p‐cymeme)Cl2]2, or the (benzene)ruthenium dichloride dimer, [Ru(benzene)Cl2]2, an N‐heterocyclic carbene (NHC) ligand, and a nitrogen containing L‐type ligand such as acetonitrile. The phosphine‐free catalyst systems showed improved or comparable activity compared to previous phosphine‐based catalytic systems. The in situ generated catalyst from [Ru(benzene)Cl2]2, an NHC ligand, and acetonitrile showed excellent activity toward reactions with cyclic secondary amines such as piperidine and morpholine. 相似文献
97.
Zhao Zhang Quan Li Sanat Chandra Maiti Xingchen Shen Jian He Fei Peng Ranjendra K. Bordia 《International Journal of Applied Ceramic Technology》2023,20(2):1060-1070
Polymer-derived amorphous SiCN has excellent high-temperature stability and properties. To reduce the shrinkage during pyrolysis and to improve the high-temperature oxidation resistance, Y2O3 was added as a filler. In this study, polymer-derived SiCN–Y2O3 composites were fabricated by mixing a polymeric precursor of SiCN with Y2O3 submicron powders in different ratios. The mixtures were cross-linked and pyrolyzed in argon. SiCN–Y2O3 composites were processed using field-assisted sintering technology at 1350°C for 5 min under vacuum. Dense SiCN–Y2O3 composite pellets were successfully made with relative density higher than 98% and homogeneous microstructure. Due to low temperature and short time of the heat-treatment, the grain growth of Y2O3 was substantially inhibited. The Y2O3 grain size was ∼1 μm after sintering. The composites’ heat capacity, thermal diffusivity, and thermal expansion coefficients were characterized as a function of temperature. The thermal conductivity of the composites ceramics decreased as the amount of amorphous SiCN increased and the coefficient of thermal expansion (CTE) of the composites increased with Y2O3 content. However, the thermal conductivity and CTE did not follow the rule of mixture. This is likely due to the partial oxidation of SiCN and the resultant impurity phases such as Y2SiO5, Y2Si2O7, and Y4.67(SiO4)3O. 相似文献
98.
The results of temperature‐dependent dielectric and rheological measurements are reported on polymer‐ceramic composite films, poly(methyl methacrylate) (PMMA) : lead titanate (PbTiO3). Analyses of relaxational processes of the PMMA host matrix have been investigated using temperature‐dependent dielectric and rheological measurements. It is found that the α‐relaxation is more significantly affected by the addition of filler in comparison to β‐relaxation. The composite films are found to have much lower dielectric constants in comparison to the pure ceramic material. Suitable models have been used to explain the observed dielectric constant of the composite films. Using rheological measurements, occurrence of reinforcement in these composite films due to the addition of ceramic filler has also been observed and the results are discussed in the article. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
99.
Pijush Kanti Chattopadhyay Srinivasan Praveen Narayan Chandra Das Santanu Chattopadhyay 《Polymer Engineering and Science》2013,53(5):923-930
Influence of organic modifying agent of clay on dispersion, distribution, hybrid microstructure formation, and associated performance properties of epoxidized natural rubber‐based composites was evaluated. Binary and ternary composites of carbon black (CB) and two organomodified layered silicates (i.e., nanomer I30E and Cloisite 30B) were prepared and characterized based on small angle X‐ray scattering, transmission electron microscopy, hydrodynamic swelling, tensile measurement, and dynamic mechanical analyses. Greater extent of exfoliation and “nanounit” formation was noted in ternary composites containing nanomer I30E, which was reflected in higher interfacial roughness (ds = 2.82) and lower radius of gyration (Rg = 205 Å). Morphological observations suggested higher nanomer I30E–CB interactions than that of Cloisite 30B–CB. The interplatelet distance in Cloisite 30B (d = 1.83 nm) stacks was lower than that of nanomer I30E (d = 2.26 nm). These two factors jointly contributed in higher breakdown of nanomer I30E stacks by CB than that of Cloisite 30B stacks. Greater exfoliation and nanounit formation in I30E–CB‐filled nanocomposite was also reflected in increased degree of crosslinking (n = 20 × 10?5%), tensile modulus/strength, half height width of damping peak (20.3°C), and filler effectiveness (C = 0.33). POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers 相似文献
100.