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Andy K. W. Ma Ali A. Alghamdi Kassem Tofailli Nicholas M. Spyrou 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(2):353-357
Early detection of the red palm weevils (RPW) is a major challenge in agriculture among all kinds of palm trees due to the nature of the insect and the difficulty to trace them through their life stages associated with the tree life. Many methods have been applied for the weevil detection such as X-ray diffraction techniques, fluoroscopy and ultrasound. On the other hand, the idea of tomography has been used for other purposes such as the determination of the age of the tree and for applied environmental studies. Such technology can also reveal the weevil in principle. In this study, we explore the use of X-ray CT for weevil detection with the Monte Carlo method. A model of the stem of a palm tree is developed for simulations. MCNPX is chosen to carry out the simulations for the radiography tally in the code. The tally records the 2D data of the X-ray beams irradiating the tree model. An iterative reconstruction method for cone beam CT is applied to obtain the 3D slices of the tree model. We are exploring the minimum number of projection angles and the detectability of the weevil. We shall also report the sensitivity of weevil detection using X-ray CT with a large set of simulations with different weevil sizes and tree diameters. 相似文献
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We consider the problem of finding the spectrum of an n × n matrix which arises in the study of a certain model of long-range interactions in a one-dimensional statistical mechanics system. Our analysis exhibits a curious resemblance of the suitably normalized distribution of eigenvalues to the Marčenko–Pastur law in the limit n → ∞. 相似文献
108.
Péter R. Surján Ágnes Szabados Péter Jeszenszki Tamás Zoboki 《Journal of mathematical chemistry》2012,50(3):534-551
Properties and some applications of strongly orthogonal geminals (APSG) are reviewed emphasizing the motivations for their use and their shortcomings. An overview presents some techniques capable of improving the APSG function. 相似文献
109.
Marina A. Khokhlova Marat O. Gallyamov Alexei R. Khokhlov 《Colloid and polymer science》2012,290(15):1471-1480
Chitosan macromolecules can be dissolved in water saturated with CO2 under high pressure, i.e. in carbonic acid. This unique biocompatible solvent with acidity regulated by the variation of applied CO2 pressure is rather promising for biomedical applications. In this work the main features of deposition of chitosan structures on the model substrate from solutions in this media were examined. After deposition on the mica surface, the obtained structures have been successfully visualised by atomic force microscopy (AFM). It has been found out that they adsorb as rather peculiar elongated objects with an average length of about 70?nm. Such conformations are believed to appear due to amphiphilic nature of chitosan semiflexible chains in agreement with recent theoretical findings. The well-defined geometry of the elongated monodispersed structures allows them to demonstrate some elements of liquid crystalline-like ordering. 相似文献
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Solubility of methane in octane + ethanol was measured at temperatures ranging from 303.15 K to 333.15 K and pressures ranging from 2.60 MPa to 12.01 MPa. Experimental data were analyzed using the Soave-Redlich-Kwong equation of state with three types of mixing rules, and the estimated average deviation from the experimental solubility data was less than 3.5 %. 相似文献