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221.
Summary Groups of galaxies are simulated by Monte Carlo technique. The mass distribution of the groups is assumed to follow a power
law. Furthermore a linear relationship between mass and luminosity is considered. The calculated velocity dispersion is compared
with the observational data and provides an estimate of the range in which the galaxy masses are distributed. It is shown,
in this case, that the mass discrepancy can cover up two orders of magnitude, such as pointed out in the literature.
The authors of this paper have agreed to not receive the proofs for correction.
Supported by Conselho Nacional de Desenvolvimento Cientifico e Tecnológico, CNPq (Brasil). 相似文献
222.
Summary The infra-red absorption bands of a representative polycylic aromatic hydrocarbon (PAH) molecule, coronene, have been examined
in the laboratory at various temperatures up to 240 °C. This paper is devoted to a systematic analysis of the temperature
variations of the integrated band intensity. A tentative interpretation of the observed behaviour is given in terms of anharmonicity
effects. These new laboratory results may be helpful in the context of the attribution of the ?unidentified? infra-red band
to PAH molecules. In addition, for the first time thermal-emission spectra of three different PAHs recorded at 240 °C are
presented.
Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990. 相似文献
223.
Summary Infrared spectroscopy can greatly help in the understanding of the active galaxies phenomena, having the advantage over optical
and UV spectroscopy of penetrating those nuclei heavily obscured by absorbing dust. The standard photoionization code CLOUDY
by Ferland has been used to predict the intensities of the infrared ionic fine-structure lines. Examples of line ratio diagrams
are presented which constrain the two main free parameters of the models (gas density and ionization parameter), and separate
line emission in the different regions of active galaxies (Seyfert and LINER type nuclei, coronal emission region, starbursts).
Moreover, some line ratio diagrams can disentangle emission-line components from shock excited and photodissociated gas. Finally
we show that the observations of these infrared lines will be possible in the near future with the ISO (Infrared Space Observatory)
spectrometers.
Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990. 相似文献
224.
Summary We discuss a SN model with s-matter in the core, compatible with the set of experimental results obtained on SN 1987A by ν-detectors
and gravitational antennas. 相似文献
225.
A capillary electrophoretic method for identifying different species of proteinaceous binders--collagen, egg white, and milk casein--is described. It allows characterisation of the proteins on the basis of the amino acid profiles obtained after their acidic hydrolysis. The profiles of the underivatised amino acids are recorded directly by capillary zone electrophoresis at pH 2.26 with the aid of a conductivity detector, thus eliminating the need for a derivatisation step. Identification is carried out by means of different relative peak areas of the amino acids. A scheme is given for identification, which is based on the main markers, hydroxyproline, proline, glycine, glutamic acid, and serine and valine. 相似文献
226.
A. Albrecht S.K. Cheung K.S. Leung C.K. Wong 《Computational Optimization and Applications》2001,19(2):179-208
This paper deals with the minimization of local forces in two-dimensional placements of flexible objects within rigid boundaries. The objects are disks of the same size but, in general, of different materials. Potential applications include the design of new amorphous polymeric and related granular materials as well as the design of package cushioning systems. The problem is considered on a grid structure with a fixed step size w and for a fixed diameter of the discs, i.e., the number of placed disks may increase as the size of the placement region increases. The near-equilibrium configurations have to be calculated from uniformly distributed random initial placements. The final arrangements of disks must ensure that any particular object is deformed only within the limits of elasticity of the material. The main result concerns -approximations of the probability distribution on the set of equilibrium placements. Under a natural assumption about the configuration space, we prove that a run-time of n+logO(1)(1/} is sufficient to approach with probability 1 – the minimum value of the objective function, where depends on the maximum of the escape depth of local minima within the underlying energy landscape. The result is derived from a careful analysis of the interaction among probabilities assigned to configurations from adjacent distance levels to minimum placements. The overall approach for estimating the convergence rate is relatively independent of the particular placement problem and can be applied to various optimization problems with similar properties of the associated landscape of the objective function. 相似文献
227.
H. Wang 《Optics & Laser Technology》1996,28(3):167-170
An optical angular deflection sensor has been implemented to assess the shape and axis position of rotating cylindrical parts. The deviation of the shape from the nominal circular cross-section (the off-round error) and the departure of the rotation axis from the geometric axis of the parts (the eccentric error) are determined. The technique is simple and inexpensive, with acceptable accuracy for mechanical engineering, is capable of monitoring rotating parts and has the potential to gauge parts on the production line. 相似文献
228.
Summary It is necessary to examine the significance of the recently discovered peak of spatial two-point correlation function determined
for the rich Abel clusters. We discuss the different possibilities to do it and propose the programme of further observations.
Riassunto è necessario esaminare il significato del picco recentemente scoperto della funzione di correlazione a due punti spaziale determinata per i cluster ricchi di Abell. Si discutono le diverse possibilità di farlo e si propone la programmazione di ulteriori osservazioni.
Резюме Отмечается важность исследования недавно обнаруженного пика пространственной функции двух-точечной корреляции, определенной для больших Абеллевых кластеров. Мы обсуждаем различные возможности проведения исследований и предлагаем программу дальнейших наблюдений.相似文献
229.
230.
Manuel A. Alba Martínez François Clautiaux Mauro Dell’Amico Manuel Iori 《Discrete Optimization》2013,10(3):210-223
We are given a set of objects, each characterized by a weight and a fragility, and a large number of uncapacitated bins. Our aim is to find the minimum number of bins needed to pack all objects, in such a way that in each bin the sum of the object weights is less than or equal to the smallest fragility of an object in the bin. The problem is known in the literature as the Bin Packing Problem with Fragile Objects, and appears in the telecommunication field, when one has to assign cellular calls to available channels by ensuring that the total noise in a channel does not exceed the noise acceptance limit of a call.We propose a branch-and-bound and several branch-and-price algorithms for the exact solution of the problem, and improve their performance by the use of lower bounds and tailored optimization techniques. In addition we also develop algorithms for the optimal solution of the related knapsack problem with fragile objects. We conduct an extensive computational evaluation on the benchmark set of instances, and show that the proposed algorithms perform very well. 相似文献