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1.
Thalia Tsiaka Panagiotis Zoumpoulakis Vassilia J. Sinanoglou Constantinos Makris Georgios A. Heropoulos Antony C. Calokerinos 《Analytica chimica acta》2015
High-energy assisted extraction techniques, like ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE), are widely applied over the last years for the recovery of bioactive compounds such as carotenoids, antioxidants and phenols from foods, animals and herbal natural sources. Especially for the case of xanthophylls, the main carotenoid group of crustaceans, they can be extracted in a rapid and quantitative way with the use of UAE and MAE. 相似文献
2.
George Lagogiannis Christos Makris Athanasios Tsakalidis 《Journal of Discrete Algorithms》2006,4(1):106-141
We consider the problem of maintaining a dynamic ordered set of n integers in a universe U under the operations of insertion, deletion and predecessor queries. The computation model used is a unit-cost RAM, with a word length of w bits, and the universe size is |U|=2w. We present a data structure that uses O(|U|/log|U|+n) space, performs all the operations in O(loglog|U|) time and needs O(loglog|U|/logloglog|U|) structural changes per update operation. The data structure is a simplified version of the van Emde Boas' tree introducing, in its construction and functioning, new concepts, which help to keep the important information for searching along the path of the tree, in a more compact and organized way. 相似文献
3.
4.
Starting from Lagrangian principles we develop a formalism suitable for describing coupled optical parity-time symmetric systems. 相似文献
5.
6.
A maximum likelihood method for estimating remote surface orientation from multi-static acoustic, optical, radar, or laser images is presented. It is assumed that the images are corrupted by signal-dependent noise, known as speckle, arising from complex Gaussian field fluctuations, and that the surface properties are effectively Lambertian. Surface orientation estimates for a single sample are shown to have biases and errors that vary dramatically depending on illumination direction. This is due to the signal-dependent nature of speckle noise and the nonlinear relationship between surface orientation, illumination direction, and fluctuating radiance. The minimum number of independent samples necessary for maximum likelihood estimates to become asymptotically unbiased and to attain the lower bound on resolution of classical estimation theory are derived, as are practical design thresholds. 相似文献
7.
K. G. Makris R. El-Ganainy D. N. Christodoulides Z. H. Musslimani 《International Journal of Theoretical Physics》2011,50(4):1019-1041
In quantum theory, any Hamiltonian describing a physical system is mathematically represented by a self-adjoint linear operator
to ensure the reality of the associated observables. In an attempt to extend quantum mechanics into the complex domain, it
was realized few years ago that certain non-Hermitian parity-time (PT\mathcal{PT}) symmetric Hamiltonians can exhibit an entirely real spectrum. Much of the reported progress has been remained theoretical,
and therefore hasn’t led to a viable experimental proposal for which non Hermitian quantum effects could be observed in laboratory
experiments. Quite recently however, it was suggested that the concept of PT\mathcal{PT}-symmetry could be physically realized within the framework of classical optics. This proposal has, in turn, stimulated extensive
investigations and research studies related to PT\mathcal{PT}-symmetric Optics and paved the way for the first experimental observation of PT\mathcal{PT}-symmetry breaking in any physical system. In this paper, we present recent results regarding PT\mathcal{PT}-symmetric Optics. 相似文献
8.
The Berlin oil channel for drag reduction research 总被引:3,自引:0,他引:3
D. W. Bechert G. Hoppe J. G. Th. van der Hoeven R. Makris 《Experiments in fluids》1992,12(4-5):251-260
For drag reduction research an oil channel has been designed and built. It is also well suited for investigations on turbulent flow and in particular on the dynamics of the viscous sublayer near the wall. The thickness of the viscous sublayer (y
+= 5) can be varied between 1 and 4 mm. Surfaces with longitudinal ribs (riblets), which are known to reduce drag, can have fairly large dimensions. The lateral spacing of the ribs can lie between 3 and 10 mm, as compared to about 0.5 mm spacing for conventional wind tunnels. It has been proved by appropriate tests that the oil channel data are completely equivalent to data from other facilities and with other mean flow geometries. However, the shear stress data from the new oil channel are much more accurate than previous data due to a novel differential shear force balance with an accuracy of ±0.2%. In addition to shear stress measurements, velocity fluctuation measurements can be carried out with hot wire or hot film probes. In order to calibrate these probes, a moving sled permits to emulate the flow velocities with the fluid in the channel at rest. A number of additional innovations contribute to the improvement of the measurements, such as, e.g., (i) novel adjustable turbulators to maintain equilibrium turbulence in the channel, (ii) a bubble trap to avoid bubbles in the channel at high flow velocities, (iii) a simple method for the precision calibration of manometers, and (iv) the elimination of (Coulomb) friction in ball bearings. This latter fairly general invention is used for the wheels of the calibration unit of the balance. The channel has a cross section of 25 × 85 cm and is 11 m long. It is filled with about 4.5 metric tons of baby oil (white paraffine oil), which is transparent and odorless like water. The kinematic viscosity of the oil is v = 1.2×10–5 m2/s, and the highest (average) velocity is 1.29 m/s. Thus, the Reynolds number range (calculated with the channel width, 0.25 m) lies between 5,000 and 26,800 for fully established turbulent flow.The material of this paper has been partly presented at the 5th European Drag Reduction Working Meeting 15th and 16th November 1990, London 相似文献
9.
Experiments have been carried out to determine the dependence of the detonation velocity in porous media, on mixture sensitivity
and pore size. A detonation is established at the top end of a vertical tube and allowed to propagate to the bottom section
housing the porous bed, comprised of alumina spheres of equal diameter (1–32 mm). Several of the common detonable fuels were
tested at atmospheric initial pressure. Results indicate the existence of a continuous range of velocities with change in
Φ, spanning the lean and the rich propagation limits. For all fuels in a given porous bed, the velocity decreases from a maximum
value at the most sensitive mixture near Φ≈1 (minimum induction length), toV/V
CJ≈0.3 at the limits. A decrease in pore size brings about a reduction inV/V
CJ and a narrowing of the detonability range for each fuel. For porous media comprised of spherical particles, it was possible
to correlate the velocity data corresponding to a variety of different mixtures and for a broad range of particle sizes, using
the following empirical expression:V/V
CJ=[1–0.35 log(d
c
/d
p)]±0.1. The critical tube diameterd
c
is used as a measure of mixture sensitivity andd
p denotes the pore diameter. An examination of the phenomenon at the composition limits, suggests that wave failure is controlled
by a turbulent quenching mechanism. 相似文献
10.
Konstantin G. Makris 《Fresenius' Journal of Analytical Chemistry》1931,84(6-7):241-242
Ohne Zusammenfassung 相似文献