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91.
Aleksey Etin Gennady E. Shter Sioma Baltianski Gideon S. Grader George M. Reisner 《Journal of the American Ceramic Society》2006,89(8):2387-2393
Elemental depth profiles of PZT films prepared by two sol–gel formulations, differing in the zirconium precursor stabilization, were investigated by SIMS analysis. Early decomposition of the zirconium precursor yielded opposing gradients of zirconium and titanium, while simultaneous late decomposition of zirconium and titanium precursors provided profile uniformity. The gradients formed during initial crystallization are irreversible. Both types of films showed excellent hysteresis; however, uniform films exhibited a much higher dielectric constant, indicating superior piezoelectric properties. Non-uniform films displayed a complex CV pattern, consistent with an inhomogeneous structure. Finally, thermal decomposition of the individual metal precursors is crucial for controlling film uniformity. 相似文献
92.
93.
Periklis E. Ergatis Panagiotis G. Massouros Georgia C. Athanasouli George P. Massouros 《国际能源研究杂志》2003,27(9):795-811
A time‐dependent coefficient of heat transfer is proposed for the computation of thermal power required, so that a room temperature reaches a desired value within a given time. A mathematical formulation of the room heating transient phenomenon is constructed in a dimensionless form. Using an integral approximate solution an analytical expression for this coefficient is provided and it is verified by diagrams adopted by DIN 4701. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
94.
Reclaiming value from post-use carbon composite 总被引:3,自引:0,他引:3
George Marsh 《Reinforced Plastics》2008,52(7):36-39
95.
96.
Sajan D. George Rajesh Komban K. G. K. Warrier P. Radhakrishnan V. P. N. Nampoori C. P. G. Vallabhan 《International Journal of Thermophysics》2007,28(1):123-132
The laser induced non-destructive photoacoustic technique has been employed to measure the thermal diffusivity of lanthanum
phosphate ceramics prepared by the sol–gel route. The thermal diffusivity value was evaluated by knowing the transition frequency
between the thermally thin to thermally thick region from the log–log plot of photoacoustic amplitude versus chopping frequency.
Analysis of the data was carried out on the basis of the one-dimensional model of Rosencwaig and Gersho. The present investigation
reveals that the sintering temperature has great influence on the propagation of heat carriers and hence on the thermal diffusivity
value. The results were interpreted in terms of variations in porosity with sintering temperature as well as with changes
in grain size. 相似文献
97.
Extended Hyperbolic Model for Sand-to-Concrete Interfaces 总被引:1,自引:0,他引:1
Jesús E. Gómez George M. Filz Robert M. Ebeling 《Canadian Metallurgical Quarterly》2003,129(11):993-1000
A relatively simple, four-parameter extended hyperbolic model for interfaces was developed for use in soil-structure interaction analyses. The model accommodates arbitrary stress path directions and includes three important elements: (1) development of a yield surface during interface shear; (2) a formulation for yield-inducing shear stiffness that is applicable to any stress path orientation; and (3) a formulation for unloading-reloading shear stiffness. The model was evaluated against the results of shear tests performed at the interface between three different types of sand and a concrete surface under a variety of stress paths. Comparisons between measured and calculated interface response indicate that the model provides accurate estimates of the response of sand-to-concrete interfaces. 相似文献
98.
Integrated model-driven dashboard development 总被引:1,自引:0,他引:1
Themis Palpanas Pawan Chowdhary George Mihaila Florian Pinel 《Information Systems Frontiers》2007,9(2-3):195-208
Business performance modeling and model-driven business transformation are two research directions that are attracting much attention lately. In this study, we propose an approach for dashboard development that is model-driven and can be integrated with the business performance models. We adopt the business performance modeling framework, and we extend it in order to capture the reporting aspect of the business operation. We describe models that can effectively represent all the elements necessary for the business performance reporting process, and the interactions among them. We demonstrate how all these models can be combined and automatically generate the final solution. We further extend the proposed framework with mechanisms that can detect changes in the models and incrementally update the deployed solutions. Finally, we discuss our experience from the application of our technique in a real-world scenario. This case study shows that our technique can be efficiently applied to and handle changes in the underlying business models, delivering significant benefits in terms of both development time and flexibility. 相似文献
99.
Data collection, both automatic and manual, lies at the heart of all empirical studies. The quality of data collected from
software informs decisions on maintenance, testing and wider issues such as the need for system re-engineering. While of the
two types stated, automatic data collection is preferable, there are numerous occasions when manual data collection is unavoidable.
Yet, very little evidence exists to assess the error-proneness of the latter. Herein, we investigate the extent to which manual
data collection for Java software compared with its automatic counterpart for the same data. We investigate three hypotheses
relating to the difference between automated and manual data collection. Five Java systems were used to support our investigation.
Results showed that, as expected, manual data collection was error-prone, but nowhere near the extent we had initially envisaged.
Key indicators of mistakes in manual data collection were found to be poor developer coding style, poor adherence to sound
OO coding principles, and the existence of relatively large classes in some systems. Some interesting results were found relating
to the collection of public class features and the types of error made during manual data collection. The study thus offers
an insight into some of the typical problems associated with collecting data manually; more significantly, it highlights the
problems that poorly written systems have on the quality of visually extracted data. 相似文献
100.