Search

At present, image analysis and digital core are the main approaches for porous media reconstruction modeling, and they are both based on the real pore skeleton physical structure of porous media. However, it is difficult to reconstruct the reservoir and seepage characteristics of the real samples because of the limitations of accuracy in characterization techniques (imaging). In order to solve this problem and break through the barriers caused by the lack of accuracy, Spin-echo serial peripheral interface sequence of low field nuclear magnetic resonance is used to test the saturated water rock core with spatially resolved T2 distributions. Based on the experimental results of 1D T2 distributions, a novel method for fine reconstruction modeling of porous media is proposed, and the porous media model reconstructed by this new method better reproduces the reservoir and seepage characteristics of the original samples. Taking some of the tested porous media cores (P58 and Y75) as examples, representative elementary volume (REV)-lattice Boltzmann method (LBM) is used to simulate the flow field. Ensuring that the error of standard case is only 0.36% when multi-relaxation time REV-LBM is used, the distribution of porosity and permeability have been calculated and compared with the experimental data. The overall permeability error of the reconstructed porous media model is only 6.15 and 7.60%, respectively. Furthermore, the porosity and permeability error of almost all measuring points can be maintained within 3 and 8%. In addition, this method improves the efficiency of the existing reconstruction modeling methods, reduces the test cost, and makes the reconstruction modeling of porous media easier to operate, which has promising development prospects.

Despite breakthroughs in modern medical care, the incidence of cardiovascular disease (CVD) is even more prevalent globally. Increasing epidemiologic evidence indicates that emerging cardiovascular risk factors arising from the modern lifestyle, including psychosocial stress, sleep problems, unhealthy diet patterns, physical inactivity/sedentary behavior, alcohol consumption, and tobacco smoking, contribute significantly to this worldwide epidemic, while its underpinning mechanisms are enigmatic. Hematological and immune systems were recently demonstrated to play integrative roles in linking lifestyle to cardiovascular health. In particular, alterations in hematopoietic stem cell (HSC) homeostasis, which is usually characterized by proliferation, expansion, mobilization, megakaryocyte/myeloid-biased differentiation, and/or the pro-inflammatory priming of HSCs, have been shown to be involved in the persistent overproduction of pro-inflammatory myeloid leukocytes and platelets, the cellular protagonists of cardiovascular inflammation and thrombosis, respectively. Furthermore, certain lifestyle factors, such as a healthy diet pattern and physical exercise, have been documented to exert cardiovascular protective effects through promoting quiescence, bone marrow retention, balanced differentiation, and/or the anti-inflammatory priming of HSCs. Here, we review the current understanding of and progression in research on the mechanistic interrelationships among lifestyle, HSC homeostasis, and cardiovascular health. Given that adhering to a healthy lifestyle has become a mainstream primary preventative approach to lowering the cardiovascular burden, unmasking the causal links between lifestyle and cardiovascular health from the perspective of hematopoiesis would open new opportunities to prevent and treat CVD in the present age. [ABSTRACT FROM AUTHOR]

A physical simulation method with a combination of dynamic displacement and imbibition was established by integrating nuclear magnetic resonance (NMR) and CT scanning. The microscopic production mechanism of tight/shale oil in pore throat by dynamic imbibition and the influencing factors on the development effect of dynamic imbibition were analyzed. The dynamic seepage process of fracking-soaking-backflow-production integration was simulated, which reveals the dynamic production characteristics at different development stages and their contribution to enhancing oil recovery (EOR). The seepage of tight/shale reservoirs can be divided into three stages: strong displacement and weak imbibition as oil produced rapidly by displacement from macropores and fractures, weak displacement and strong imbibition as oil produced slowly by reverse imbibition from small pores, and weak displacement and weak imbibition at dynamic equilibrium. The greater displacement pressure results in the higher displacement recovery and the lower imbibition recovery. However, if the displacement pressure is too high, the injected water is easy to break through the front and reduce the recovery degree. The higher the permeability, the greater the imbibition and displacement recovery, the shorter the time of imbibition balance, and the higher the final recovery. The fractures can effectively increase the imbibition contact area between matrix and water, reduce the oil-water seepage resistance, promote the oil-water displacement between matrix and fracture, and improve the oil displacement rate and recovery of the matrix. The soaking after fracturing is beneficial to the imbibition replacement and energy storage of the fluid; also, the effective use of the carrying of the backflow fluid and the displacement in the mining stage is the key to enhancing oil recovery. [ABSTRACT FROM AUTHOR]

In the Synthetic Aperture Radar (SAR) remote sensing imagery of complicated scenes (especially urban scenes), there are a large number of lines and surfaces, such as roads in urban areas and the surfaces of buildings. These microwave-signal-scattering features have strong directivity. Traditional SAR acquires the scattering information of a scene from a single observation, and traditional imaging algorithms are based on the point target model, which makes the main features of the lines and surfaces in traditional SAR images appear as a series of strong scattering points rather than line-scattering and surface-scattering features. This outcome ultimately causes the target to be discontinuous in the SAR image, thus making the SAR image difficult to interpret. Therefore, in this study, we conducted an in-depth and meticulous investigation of the SAR imaging mechanism for lines and surfaces by establishing a parametric echo model of typical lines and triangular surfaces. Based on the proposed parametric model, we performed parametric imaging of these lines and surfaces. Based on our results, we propose a parametric imaging method, in which the typical lines and surfaces are classified and determined based on Bayesian theory and the proposed parametric model. Then, an SAR image can be obtained that effectively characterizes the scattering features of the line and surface targets by visual imaging, which effectively facilitates SAR image interpretation. The results of our numerical simulation experiments verify the validity of the proposed method.

The hole collector in silicon heterojunction cells serves not only as an integral component of the p / n junction, determining the strength of the built-in electric field, but also as a layer responsible for hole transport, thereby affecting carrier transport capacity. To enhance carrier extraction and transport properties of the hole collector, various interface treatments have been employed on p -type nanocrystalline (p -nc-Si:H) hole collectors. Through an examination of characteristics such as dark conductivity, crystallinity, and contact resistance, the impact of interface treatment on p -nc-Si:H hole collectors is clarified. Furthermore, considering distinct requirements for the hole collector at different locations, interface treatment processes are optimized accordingly. The introduction of interface treatment on p -nc-Si:H hole collectors has demonstrated significant enhancement of both front and rear junction cell efficiencies, which increased from 17.74% to 21.61% and from 16.83% to 20.92%, respectively. [ABSTRACT FROM AUTHOR]