446 research outputs found
Прогнозирование и вероятностная оценка долговечности технических объектов
На основе методологии марковского анализа надежности предложен вероятностный подход к прогнозированию и оценке долговечности технических объектов. Разработана математическая модель прогнозирования долговечности с использованием статистических данных, характеризующих начальное и конечное распределение продолжительности срока службы технических объектов.На основі методології марківського аналізу надійності запропоновано ймовірнісний підхід до прогнозування та оцінки довговічності технічних об’єктів. Розроблено математичну модель прогнозування довговічності з використанням статистичних даних, що характеризують початковий та кінцевий розподіл тривалості терміну служби технічних об’єктів.Based on the methodology of the Markov analysis, a probabilistic approach to forecast and estimation of the longevity of technical objects is offered. A mathematical model of the longevity forecast is developed with the use of statistical data characterizing the initial and final distribution of the service term of technical objects
A quantitative comparison of dispersed spore/pollen and plant megafossil assemblages from a Middle Jurassic plant bed from Yorkshire, UK
Detailed quantitative data has previously been collected from plant megafossil assemblages from a Middle Jurassic (Aalenian) plant bed from Hasty Bank, North Yorkshire, UK. We conducted a similar analysis of palynological dispersed sporomorph (spore and pollen) assemblages collected from the same section using the same sampling regime: 67 sporomorph taxa were recorded from 50 samples taken at 10 cm intervals through the plant bed. Basic palynofacies analysis was also undertaken on each sample. Both dispersed sporomorph and plant megafossil assemblages display consistent changes in composition, diversity (richness), and abundance through time. However, the dispersed sporomorph and plant megafossil records provide conflicting evidence for the nature of parent vegetation. Specifically, conifers and ferns are underrepresented in plant megafossil assemblages, bryophytes and lycopsids are represented only in sporomorph assemblages, and sphenophytes, pteridosperms, Caytoniales, Cycadales, Ginkgoales and Bennettitales are comparatively underrepresented in sporomorph assemblages. Combined multivariate analysis (correspondence analysis and nonmetric multidimensional scaling) of sporomorph occurrence/abundance data demonstrates that temporal variation in sporomorph assemblages is the result of depositional change through the plant bed. The reproductive strategies of parent plants are considered to be a principal factor in shaping many of the major abundance and diversity irregularities between dispersed sporomorph and plant megafossil data sets that seemingly reflects different parent vegetation. Preferential occurrence/preservation of sporomorphs and equivalent parent plants is a consequence of a complex array of biological, ecological, geographical, taphonomic, and depositional factors that act inconsistently between and within fossil assemblages, which results in notable discrepancies between data sets
Банда і злочинна організація: проблема співвідношення понять
Розкривається
проблема
співвідношення
понять
«банда» та «злочинна
організація».
На основі
критичного
аналізу існуючих
наукових
підходів до визначення
сутнісних ознак
понять
«банда» та «злочинна
організація» та судової
практики
розгляду
кримінальних
справ про злочини,
вчинені
такими
злочинними
об’єднаннями,
автором
пропонуються
конкретні
підходи
до їх співвідношення.Раскрывается
проблема
соотношения
понятий
«банда» и «преступная
организация». На основе
критического
анализа
существующих
научных
подходов
на определение
сущностных
признаков
понятий
«банда» и «преступная
организация» и судебной
практики
рассмотрения
уголовных
дел о преступлениях,
совершенных
такими
преступными
объединениями
автором
предлагаются
конкретные
подходы
к их соотношению.Opens up the problem of correlation of the concepts «band» and «criminal organization».
Founded on critical analysis of the existing scientific approaches at definition of the essence
signs of the concepts «band» and «criminal organization» and judicial practice of consideration
criminal cases about crimes are committed by that criminal associations author offers
certain approaches at their correlation
Light incoherence due to quantum-gravitational fluctuations of the background space
Based on the theory of mutual coherence of light from an extended incoherent
quasi-monochromatic source (providing a basis of stellar interferometry) we
estimate the degree of light incoherence due to quantum-gravitational
fluctuations of the background metric. It is shown that the stellar
interferometry observational data considered in the literature for a last few
years as a manifestation against the Planck scale quantum-gravitational
fluctuations of the background metric have no chance for detecting such an
effect.Comment: 5 pages; Version to appear in Astroparticle Physic
Optimal Concentration of Light in Turbid Materials
In turbid materials it is impossible to concentrate light into a focus with
conventional optics. Recently it has been shown that the intensity on a dyed
probe inside a turbid material can be enhanced by spatially shaping the wave
front of light before it enters a turbid medium. Here we show that this
enhancement is due to concentration of light energy to a spot much smaller than
a wavelength. We focus light on a dyed probe sphere that is hidden under an
opaque layer. The light is optimally concentrated to a focus which does not
exceed the smallest focal area physically possible by more than 68%. A
comparison between the intensity enhancements of both the emission and
excitation light supports the conclusion of optimal light concentration.Comment: We corrected an ambiguous description of the focus size in our
abstract and text pointed out by an anonymous refere
Experimental verification of the Heisenberg uncertainty principle for hot fullerene molecules
The Heisenberg uncertainty principle for material objects is an essential
corner stone of quantum mechanics and clearly visualizes the wave nature of
matter. Here we report a demonstration of the Heisenberg uncertainty principle
for the most massive, complex and hottest single object so far, the fullerene
molecule C70 at a temperature of 900 K. We find a good quantitative agreement
with the theoretical expectation: dx * dp = h, where dx is the width of the
restricting slit, dp is the momentum transfer required to deflect the fullerene
to the first interference minimum and h is Planck's quantum of action.Comment: 4 pages, 4 figure
Earliest Jurassic River Deposits in Northeast Bavaria, Germany
In northeastern Bavaria/Germany the onset of the Jurassic is indicated by fluvial deposits. Their Jurassic age is proved by paleoflora. The deposits start with a fluvial channel fill composed by fine-grained sandstone and coaly shale containing a small paleofloral assemblage. The streams are draining the slightly higher hinterland of the Bohemian-Variscan Mountains. This channel follows unconformably late Triassic beds of alluvial sheet flows with clayey load and few sandy and muddy channels originating from a mountainous hinterland with subtropical–tropical weathering (Rhaetian Itz Subformation). In contrast to the paleofloral cut at the Triassic/Jurassic boundary the lithologic development does not indicate a severe cut. Only later a change of the relief and the lithology is visible
Space-Time Approach to Scattering from Many Body Systems
We present scattering from many body systems in a new light. In place of the
usual van Hove treatment, (applicable to a wide range of scattering processes
using both photons and massive particles) based on plane waves, we calculate
the scattering amplitude as a space-time integral over the scattering sample
for an incident wave characterized by its correlation function which results
from the shaping of the wave field by the apparatus. Instrument resolution
effects - seen as due to the loss of correlation caused by the path differences
in the different arms of the instrument are automatically included and analytic
forms of the resolution function for different instruments are obtained. The
intersection of the moving correlation volumes (those regions where the
correlation functions are significant) associated with the different elements
of the apparatus determines the maximum correlation lengths (times) that can be
observed in a sample, and hence, the momentum (energy) resolution of the
measurement. This geometrical picture of moving correlation volumes derived by
our technique shows how the interaction of the scatterer with the wave field
shaped by the apparatus proceeds in space and time. Matching of the correlation
volumes so as to maximize the intersection region yields a transparent,
graphical method of instrument design. PACS: 03.65.Nk, 3.80 +r, 03.75, 61.12.BComment: Latex document with 6 fig
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