In conditions of low visibility, the scattering effect of atmospheric particles can result in images captured by cameras exhibiting a number of problems, including reduced contrast, color distortion, ...and blurred details. These issues can have a significant impact on the clarity and recognition of the images. In response to these issues, this study combines atmospheric scattering models with wavelet transform, introduces non-blind deconvolution algorithms and, finally, designs a special gamma correction function to ultimately develop a new foggy image restoration model. The relevant outcomes showed that when the dehazing model processed most image samples, its edge preservation was mainly concentrated in a relatively high range, namely 0.80, 0.96. From the perspective of the structural similarity index, the discrete wavelet transform achieved the highest value of 0.8264. In addition, the peak signal-to-noise ratio of the improved gamma correction function was 18.346. The proposed algorithm for restoring foggy images has the advantages of high clarity, strong color restoration ability, and fast restoration speed, providing more reliable and efficient image data support for applications in related fields.
Apoptosis of chondrocytes are the main initiator of osteoarthritis (OA) and can be explained by oxidative stress and endoplasmic reticulum (ER) stress, thus the pharmacological interventions aimed at ...inhibiting of these pathways may be a promising approach for the management of OA. Quercetin is a member of the flavonoid family and has antioxidant and anti‐inflammatory properties in degenerative diseases. However, its effects and potential mechanisms on the pathological process of OA are not very clear. The present study aimed to investigate the protective effects of quercetin on OA and the underlying mechanisms. The tert‐butyl hydroperoxide (TBHP)‐stimulated rat chondrocytes and destabilization of the medial meniscus OA rat model was used to explore the protective effects of quercetin. Our results showed that quercetin treatment can attenuate oxidative stress, ER stress, and associated apoptosis. Moreover, quercetin inhibited ER stress through activating the sirtuin1/adenosine monophosphate‐activated protein kinase (SIRT1/AMPK) signaling pathway. The protective effects of quercetin were also observed in OA rat model which is evidenced by abolished cartilage degeneration and decreased chondrocytes apoptosis in the knee joints. Our results suggested that quercetin is a promising treatment for OA.
Our results showed that quercetin (QUE) treatment can attenuate oxidative stress, endoplasmic reticulum (ER) stress, and associated apoptosis. Moreover, QUE inhibited endoplasmic reticulum (ER) stress through activating the sirtuin1/adenosine monophosphate‐activated protein kinase (SIRT1/AMPK) signaling pathway. The protective effects of QUE were also observed in osteoarthritis (OA) rat model.
This article proposes a reversible information hiding algorithm based on chaos and histogram translation in ciphertext images to address the shortcomings of traditional algorithms such as separation ...of encryption and information hiding processes, small embedding capacity, and inflexible operation. This article first uses grayscale images as a carrier for digital images, analyzes and studies existing reversible information hiding algorithms in the ciphertext domain of grayscale images, and improves them to solve the problems of existing reversible information hiding algorithms in the ciphertext domain. Secondly, the sender first encrypts the image and then embeds the information; The receiving end can either decrypt and extract information first, or extract and decrypt information first. Finally, we selected a Lena grayscale image with 513 pixels × 513 pixels for the experiment, dividing the image into 4 blocks (r = 4), and scrambling the pixel positions using DLKL transform for each block, with parameters k = 4, n = 7, q = 59. The simulation results show that the algorithm is easy to implement and can effectively improve the capacity of information embedding.
Abstract
We first described the 2019 novel coronavirus infection in 10 children occurring in areas other than Wuhan. The coronavirus diseases in children are usually mild and epidemiological exposure ...is a key clue to recognize pediatric case. Prolonged virus shedding is observed in respiratory tract and feces at the convalescent stage.
•A general framework is developed in regional heterogeneous reservoirs.•Arbitrary boundary shape is considered in the model.•New solutions for fractured horizontal well with finite conductivity are ...obtained.
The focus of this paper is to establish a new general model framework considering both hydraulic fractures with finite conductivity and heterogeneous characteristics of multiple connected regions by using boundary element method. With this framework, we can calculate the pressure performance of any heterogeneous reservoir. The innovation is that the complex fracture flow, boundary shape and heterogeneous characteristics can be flexibly considered in the model. Transient pressure of fractured horizontal wells in heterogeneous reservoir is obtained by using Stehfest numerical inversion method. Subsequently, this proposed regional heterogeneity model was validated by using numerical simulation methods. The results show that the proposed heterogeneous model can be divided into five flow segments, which are bilinear flow, linear flow, radial flow, first boundary dominated flow and second boundary dominated flow. However, the research results show that the presence or absence of some flow sections is closely related to the regional permeability ratio and the regional storage capacity ratio. As the two most important parameters of heterogeneous reservoir, the permeability ratio and regional storage capacity of heterogeneous reservoir will have a huge impact on the pressure response and pressure field. The sensitivity analysis shows that these two factors will lead to the deformation of the pressure field distribution and affect the flow characteristics, and cause some flow segments to fail to appear. The smaller the regional storage capacity ratio, the deeper the V-shape, and the more fluid supplied from the outer zone to the inner zone. This study also suggests that the fracture conductivity mainly affects the early flow characteristics, and the smaller the conductivity, the greater the pressure loss. In addition, irregular boundary will also cause important deformation of pressure field, and the area size will affect the late flow characteristics, and the smaller the area, the greater the pressure loss. The new semi-analytical solutions can form a series of typical curves and be applied to the well test analysis of multi-stage fracturing horizontal wells in heterogeneous and unconventional oil and gas reservoirs. The findings of this study can help for better understanding of the influence of reservoir heterogeneity on pressure response and find some applications in well testing for inverse problems in heterogeneous reservoirs.
•A general model in discretely fractured rectangular reservoir is developed.•Flow characteristics of the complex fracture networks is analyzed in detail.•The pressure field will change significantly ...in discretely fractured reservoirs.•The effect of discharge area and eccentric position on type curves is critical.
The focus of this paper is to establish a general model, which is capable of dynamic simulation of discrete fractures at any position and arbitrary distribution in rectangular closed reservoir. In this article, a semi-analytical model for fractured horizontal wells with random distributed fracture networks is proposed to facilitate pressure transient response using a double node method. A rectangular closed reservoir model and fracture network flow model are established respectively, and then coupled at the fracture wall. In order to deal with the flow distribution at the fracture intersection, a simple adaptive material balance method is proposed in this paper, which successfully solves the flow distribution at the intersection. Using advanced mathematical means, the model is successfully solved in Laplace space, and then the pressure response solution in real space is obtained by Stehfest numerical inversion method. The obtained solutions are verified and compared with the numerical simulation results. The calculation results show that the flow characteristics of the orthogonal fracture network can be roughly divided into six stages, namely, bi-linear flow, first linear flow, first radial flow, second linear flow, second radial flow and boundary dominated flow. However, these flow characteristics will deviate or even be missing, depending on the complexity of the fracture network. Finally, the effects of some important parameters (such as dimensionless fracture network conductivity, main fracture length, fracture network density, reservoir area and eccentric position) on pressure response and pressure field distribution are discussed in detail.
The well log inversion has been widely applied to forecast coal texture distribution due to its effectiveness and low investment. However, most research missed the low resolution of well logging data ...caused by the “boundary effect”, which make it difficult to identify thin layers. Here a method to improve the vertical resolution of logging curves by Wavelet Transform was applied. The original logging curve was decomposed by two-level wavelet decomposition using sym 8 mother wavelet, and then the high-frequency wavelet coefficient (d2) was weighted to reconstruct a new log curve to enhance the resolution of the thin-layer. Based on 160 reconstructed training logging datasets, the Linear Discrimination Analysis was used to establish a quantitative coal texture identification model by reducing the dimensionality of the data points and projecting them into a two-dimensional space. The validation results of coal texture are in good agreement with the coal core. Compared with the non-reconstructed curve, the recognition accuracy is greatly improved, especially for layers with a thickness < 20 cm. The combination of Wavelet Transform and Linear Discrimination Analysis provides a new way to predict coal texture using geophysical logging data. This method has been successfully applied to multiple (>20 layers) and thin (generally <2 m in thickness) seams in the western Guizhou province of China, with recognition accuracy >85%.
Heavy oil is an important part of petroleum hydrocarbon energy. With the depletion of conventional crude oil reserves, successful and efficient exploitation of heavy oil resources is becoming ...increasingly important. This article focuses on the nine relatively mature heavy oil development technologies from the perspectives of the level of understanding of the mechanism and the scale of the mining field: steam huff and puff, steam flooding, steam-assisted gravity drainage (SAGD), in situ combustion, thermochemical combined flooding, multicomponent thermal fluid, polymer flooding, chemical viscosity reduction development, and microbial oil recovery, which are divided into two technical categories: thermal recovery and cold recovery development. The basic development principles are explained, and application examples of the two categories of techniques are provided. It is pointed out that thermal compounding, cold mining development, and nanomaterial applications will be the three development trends in heavy oil development.
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