Degree Of Superposition Research Articles

Research on sand body architecture at the intersection of a bidirectional sedimentary system in the Jiyuan area of Ordos Basin

The exploration and development of the dual-provenance lower assemblage of the Yanchang Formation in the Jiyuan area has progressed rapidly. At the intersection of this bidirectional provenance system, a complex and variable spatial combination of sand bodies formed, resulting in significant structural heterogeneity in the development and distribution of reservoirs. Based on previous studies, this paper combines core data and logging data with a large number of analytical tests and production performance data to carry out research on the Chang 82–Chang 9 reservoir group in the lower assemblage of the Yanchang Formation in the Shijiawan-Buziwan area. Based on the analysis of sedimentary conditions, the sand body development pattern at the intersection of the bidirectional sedimentary system in the study area was analysed by stepwise dissection of the sand body architecture. After the types and characteristics of the 4th- to 5th-level architectural elements were determined, the spatial distribution of the combinations of these elements was assessed and combined with logging discriminant analysis and geometric shape prediction methods to identify a ‘prism’ architectural distribution pattern. The architectural elements are connected with the distribution of diagenetic facies, the spatial distribution patterns of different types of diagenetic facies under the constraints of the architecture are summarized by region, and the locations of potential favourable reservoir development are discussed. The results show that the degree of superposition and combination of the eight skeletal architectural elements in the target layers gradually deteriorate from the bottom to the top. In addition, the development scale and degree of architectural elements in the braided river delta system in the west are better than those in the meandering river delta system in the east. In the different sedimentary areas, the spatial combination styles of the architectural elements are quite different, and the combination of these elements gradually changes from a combination of braided channels (FA1) and abandoned channels (FA2) to a combination of underwater distributary channels (FA4). Matching of the distribution of diagenetic facies with the distribution of architectural elements reveals that the diagenetic facies dominated by intergranular pores and dissolution pores (associated with good reservoir physical properties) are usually found at the bottom or in the lower to middle parts of the skeletal architectural elements.

What is the physics behind the Larson mass–size relation?

ABSTRACTDifferent studies have reported a power-law mass–size relation M ∝ Rq for ensembles of molecular clouds. In the case of nearby clouds, the index of the power-law q is close to 2. However, for clouds spread all over the Galaxy, indexes larger than 2 are reported. We show that indexes larger than 2 could be the result of line-of-sight superposition of emission that does not belong to the cloud itself. We found that a random factor of gas contamination, between 0.001 per cent and 10 per cent of the line of sight, allows to reproduce the mass–size relation with q ∼ 2.2–2.3 observed in Galactic CO surveys. Furthermore, for dense cores within a single cloud, or molecular clouds within a single galaxy, we argue that, even in these cases, there is observational and theoretical evidence that some degree of superposition may be occurring. However, additional effects may be present in each case, and are briefly discussed. We also argue that defining the fractal dimension of clouds via the mass–size relation is not adequate, since the mass is not necessarily a proxy to the area, and the size reported in M−R relations is typically obtained from the square root of the area, rather than from an estimation of the size independent from the area. Finally, we argue that the statistical analysis of finding clouds satisfying the Larson’s relations does not mean that each individual cloud is in virial equilibrium.

IDENTIFICATION AND DETERMINATION OF LIGHT MARKS WHEN THEY OVERLAP IN OPTICAL CONTROL SYSTEMS

The issues of identification and determination of the relative position of localized light marks and images of small-sized objects recorded by an optical-electronic system (OES) are considered. A physical model and a research virtual device (VI) were developed on the basis of National Instruments software for identification and coordinate determination of two light marks at their different relative positions and the ratio of their intensities. It is shown that the use of a mathematical method for analyzing the illumination contour of two light labels on the basis of a continuous wavelet transform (CWT) allows identifying each label separately and determining the degree of superposition of their images. It is shown that the amplitudes and positions of the maxima of the CWT coefficients are related to the relative shift of the illuminance contours of the light marks, as the marking contours separate, the dependence of the position of the maxima becomes linear. The result of comparing the experimental data with theoretical calculations for the models of light labels showed a match within 25 %.

Response Characteristics and Mechanisms of Dynamic Fluid Field for Well Interference of Coal Bed Methane Group Wells in Production Block

According to production data and reservoir data of 16 coal bed methane (CBM) wells in southern Qinshui Basin, this paper draws the contour map of groundwater fluid potential at 8 moments in the production monitoring area and establishes three-dimensional visualization model of superimposed pressure drop funnel in CBM well with Matlab mathematical software; discusses the response relationship between well interference and dynamic fluid field on the basis of analyzing dynamic change features of groundwater fluid potential and evolution features of superimposed pressure drop funnel and puts forward an evaluation program of dynamic fluid field for well interference. The research result shows that dynamic fluid field has a good response relationship with well interference of CBM well and is manifested by the corresponding relation between evolutionary phase and space distribution. Evolution features of dynamic fluid field can be used to judge the phase and degree of well interference. The stage when well interference does not form is corresponding to the failure stage of original groundwater fluid potential and evolutionary phase of single-well pressure drop funnel. CBM wells do not have well interference and pressure drop funnel exists in the form of independent funnel. The space distribution of groundwater fluid potential is balanced. Due to the influence of groundwater fluid potential distribution, formation water flows to the shaft from the scope of pressure drop funnel. The stage when well interference forms preliminarily is corresponding to the stage of differentiation and reconstruction of groundwater fluid potential and formation stage of local superimposed pressure drop funnel. CBM wells start to have well interference and the degree of superposition of pressure drop funnel increases in local areas. “Low-lying” collecting area of groundwater fluid potential forms in superimposed area. Coal bed water flows to this area. The stabilization stage of well interference is corresponding to the formation and stabilization stage of new groundwater fluid potential and formation stage of regional superimposed pressure drop funnel. Regional superimposed pressure drop funnel is basically mature. New groundwater fluid potential centering on superimposed pressure drop funnel basically forms and coal bed water flows to the center of well network from surrounding areas.

Impact of chiasma opticum malformations on the organization of the human ventral visual cortex.

Congenital malformations of the optic chiasm, such as enhanced and reduced crossing of the optic nerve fibers, are evident in albinism and achiasma, respectively. In early visual cortex the resulting additional visual input from the ipsilateral visual hemifield is superimposed onto the normal retinotopic representation of the contralateral visual field, which is likely due to conservative geniculo-striate projections. Counterintuitively, this organization in early visual cortex does not have profound consequences on visual function. Here we ask, whether higher stages of visual processing provide a correction to the abnormal representation allowing for largely normal perception. To this end we assessed the organization patterns of early and ventral visual cortex in five albinotic, one achiasmic, and five control participants. In albinism and achiasma the mirror-symmetrical superposition of the ipsilateral and contalateral visual fields was evident not only in early visual cortex, but also in the higher areas of the ventral processing stream. Specifically, in the visual areas VO1/2 and PHC1/2 no differences in the extent, the degree of superposition, and the magnitude of the responses were evident in comparison to the early visual areas. Consequently, the highly atypical organization of the primary visual cortex was propagated downstream to highly specialized processing stages in an undiminished and unchanged manner. This indicates largely unaltered cortico-cortical connections in both types of misrouting, i.e., enhanced and reduced crossing of the optic nerves. It is concluded that main aspects of visual function are preserved despite sizable representation abnormalities in the ventral visual processing stream.

A model for the generation of synthetic intramuscular EMG signals to test decomposition algorithms.

As more and more intramuscular electromyogram (EMG) decomposition programs are being developed, there is a growing need for evaluating and comparing their performances. One way to achieve this goal is to generate synthetic EMG signals having known features. Features of interest are: the number of channels acquired (number of detection surfaces), the number of detected motor unit action potential (MUAP) trains, their time-varying firing rates, the degree of shape similarity among MUAPs belonging to the same motor unit (MU) or to different MUs, the degree of MUAP superposition, the MU activation intervals, the amount and type of additive noise. A model is proposed to generate one or more channels of intramuscular EMG starting from a library of real MUAPs represented in a 16-dimensional space using their Associated Hermite expansion. The MUAP shapes, regularity of repetition rate, degree of superposition, activation intervals, etc. may be time variable and are described quantitatively by a number of parameters which define a stochastic process (the model) with known statistical features. The desired amount of noise may be added to the synthetic signal which may then be processed by the decomposition algorithm under test to evaluate its capability of recovering the signal features.

DELAYED KINETICS OF SQUID AXON POTASSIUM CHANNELS DO NOT ALWAYS SUPERPOSE AFTER TIME TRANSLATION

The activation of potassium ion conductance in squid axons by voltage-clamp depolarization is delayed when the depolarizing step is preceded by a conditioning hyperpolarization of the axonal membrane. Moreover, the control conductance kinetics superpose with the delayed kinetics when they are translated along the time axis by an amount equal to the delay. We have found that the degree of superposition with internally perfused axons depends upon voltage-clamp protocol. The kinetics superpose almost exactly for modest test depolarizations, whereas they clearly fail to superpose completely for more positive levels of membrane depolarization. We have modeled these results by incorporating a time dependence into the rate constant of activation of potassium channel gates in the Hodgkin and Huxley model of potassium ionic conductance.