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排序方式: 共有294条查询结果,搜索用时 15 毫秒
101.
Raje Gangadharan Jayaraman Kalaiselvi Devaraj Shanmukaraj Balan Palanivel Sriramulu Mohan Ramaswamy Murugan 《Journal of Alloys and Compounds》2002,340(1-2):95-100
The ionic conductivity and thermo-Raman spectra of anhydrous sodium pyrophosphate Na4P2O7 were measured dynamically in the temperature range from 25 to 600 °C with a heating rate of 2 °C min−1 to understand the structural evolution and phase transformation involved. The DSC thermogram was also measured in the same thermal process for the phase transformation investigation. The spectral variations observed in the thermo-Raman investigation indicated the transformation of Na4P2O7 from low temperature phase () to high temperature phase () proceeded through pre-transitional region from 75 to 410 °C before the major orientational disorder at 420 °C and minor structural modifications at 511, 540 and 560 °C. The activation energies and enthalpies of the proposed phase transformations were determined. The possible mechanism for temperature dependent conductivity in Na4P2O7 was discussed with the available data. 相似文献
102.
103.
Singh RS Sanagapalli S Jayaraman V Singh VP 《Journal of nanoscience and nanotechnology》2004,4(1-2):176-182
A new method for fabricating nanoporous CdS films is reported. It involves exposing the CdS solution with ultrasound waves during the process of dip coating. Indium tin oxide (ITO)-coated glass and plastic (commercial transparency) were used as substrates. In each case three different precursors were used for dip coating. The precursors used were CdCl2 and thiourea in one case and CdS nanoparticles prepared by sonochemical and microwave-assisted methods in the other two cases. X-ray diffraction studies performed on these powders show a phase corresponding to cubic CdS. The Field Emission Scanning Electron Microscopy (FE-SEM) images of the films on plastic showed uniform pores with a diameter of 80 nm for all three methods. Optical absorption measurements indicated a blue shift and multiple peaks in the absorption curve. The FE-SEM observations of the films on an ITO/glass substrate indicated a crystalline film with voids. The UV-vis absorption results indicated a blue shift in the absorption with an absorption edge at 435, 380, and 365 nm for CdS films made by solution growth, sonochemical, and microwave routes, respectively. The magnitude of the absorption is dependent on film thickness, and the observed blue shift in the absorption can be explained on the basis of quantum confinement effects. 相似文献
104.
P. Rangaswamy M. A. M. Bourke R. Von Dreele K. Bennett M. R. Daymond N. Jayaraman 《Metallurgical and Materials Transactions A》2000,31(3):889-898
Residual strain and texture variations were measured in two titanium matrix composites reinforced with silicon carbide fibers
(Ti/SiC) of similar composition but fabricated by different processing routes. Each composite comprised a Ti-6242 α/β matrix alloy containing vol 35 pct continuous SiC fibers. In one, the matrix was produced by a plasma sprayed (PS) route,
and in the other by a wiredrawn (WD) process. The PS and WD composites were reinforced with SCS-6 (SiC) and Trimarc (SiC)
fibers, respectively. The texture in the titanium matrices differed significantly. The titanium matrix for the PS material
exhibited random texture pre and post fabrication of the composite. For the WD material, the starting texture of the monolithic
titanium matrix was ≈17 times random, but after consolidation into composite form, it was ≈6 times random. No significant
differences were noted in the fiber-induced matrix residual strains between the composites prepared by the two procedures.
However, the Trimarc (WD) fibers recorded higher (≈1.3 times) compressive strains than the SCS-6 (PS) fibers. Stresses and
stress balance results are reported. Plane-specific elastic moduli, measured in load tests on the unreinforced matrices, showed
little difference.
This article is based on a presentation made in the Symposium “Mechanisms and Mechanics of Composites Fracture” held October
11–15, 1998, at the TMS Fall Meeting in Rosemont, Illinois, under the auspices of the TMS-SMD/ASM-MSCTS Composite Materials
Committee. 相似文献
105.
Jayaraman V. Goodnough T.J. Beam T.L. Ahedo F.M. Maurice R.A. 《Photonics Technology Letters, IEEE》2000,12(12):1595-1597
Long-wavelength vertical cavity surface emitting lasers (VCSELs) have thus far not provided substantial continuous-wave (CW) output power above 70°C. We describe recent advances using a vertically integrated 850 nm optical pump with a 1310-nm VCSEL. Using this approach, the devices described demonstrate record high temperature performance. We show single-transverse mode CW operation from -40 to +115°C, 0.5 mw optical power up to +85°C, and excellent device uniformity 相似文献
106.
107.
Desagani Dayananda Venkateswara Rao Sarva Sivankutty Vadakkethonippurathu Prasad Jayaraman Arunachalam 《Particulate Science and Technology》2015,33(1):8-16
In this paper, we report a simple aqueous solution based chemical method for preparation of mesoporous γ-Al2O3 which can be used for removal of fluoride ions from water. The synthesized Al2O3 and commercial Al2O3(Grade AD101-F, ACE Manufacturing and Marketing, Baroda, India) were characterized by using powder x-ray diffractometer, N2 adsorption–desorption surface area and pore size analyzer, and high resolution transmission electron microscope. Synthesized Al2O3 contains a wormhole-like mesoporous structure with 358.7 m2 g?1 Brunauer–Emmett–Teller (BET) surface area and 0.8 cm3 g?1 pore volume. Batch adsorption studies were performed to determine the fluoride adsorption capacity of Al2O3. The effect of different parameters such as contact time, initial fluoride concentration, pH, and adsorbent dose was studied to understand the fluoride adsorption behavior of the synthesized Al2O3 under various conditions. The kinetics results showed that the fluoride adsorption on synthesized Al2O3 followed pseudo-second-order kinetics. Adsorption equilibrium data fitted well to the Freundlich equation and indicated multilayer adsorption of fluoride on the surface of Al2O3. Synthesized Al2O3 demonstrated significantly improved fluoride adsorption capacity and faster kinetics than commercial Al2O3. 相似文献
108.
Dongheon Lee Arul Jayaraman Joseph S.-I. Kwon 《American Institute of Chemical Engineers》2020,66(5):e16925
Cells in a genetically homogeneous cell-population exhibit a significant degree of heterogeneity in their responses to an external stimulus. To understand origins and importance of this heterogeneity, individual-based population model (IBPM), where parameters follow probability density functions (PDFs) instead of being constants, has been previously developed. However, parameter identification for an IBPM is challenging as estimating PDFs is computationally expensive. Also, because of experimental limitations and nonlinearity of models, not all parameters' PDFs are identifiable. Motivated by the above considerations, a new methodology is proposed in this study. First, a subset of parameters whose PDFs is identifiable are determined through sensitivity analysis, and only these PDFs are estimated. Second, an artificial neural network model is developed to find an empirical relation between these parameter and output PDFs to reduce computational costs of the parameter identification. The proposed approach is validated by estimating PDFs of parameters of a tumor necrosis factor-α signaling model. 相似文献
109.
110.
Nurul Fazita Mohammad Rawi Krishnan Jayaraman Debes Bhattacharyya 《Polymer Composites》2014,35(10):1888-1899
The main objective of this study is to explore the potential of using totally green composites made from renewable resources in packaging applications as compared to conventional thermoplastics. In this work, we undertook a comparative study of the functional properties related to the packaging applications of bamboo fabric–Polypropylene (PP) and bamboo fabric–Poly(lactic acid) (PLA) composites. Results indicate that Charpy impact strength was increased from 37.5 to 126 J/m for bamboo fabric–PLA composites and 204 to 278 J/m for bamboo fabric–PP composites compared to the pure polymers. Drop weight impact tests were also performed and the same trend was observed. Results of thermogravimetric analysis, differential scanning calorimetry, and heat deflection temperature analysis have shown that the addition of bamboo fabric improved the thermal resistance of these composites. Results indicate that bamboo fabric is a potential reinforcement for PLA composites, but possible packaging applications should avoid high humidity environment. POLYM. COMPOS., 35:1888–1899, 2014. © 2014 Society of Plastics Engineers 相似文献