A Simulation Experimental Study on the Gas-Water Saturation Characteristics in the Process of Constant-Speed Gas Production Based on the Microscopic Model

This paper presents the important findings of research work that was undertaken on the residual water saturation of gas reservoirs that arises from the decrease in pore pressure during a constant-speed gas production process. To study the changes and distribution regularities of water-gas saturation, we used a micro-glass model to conduct a simulation study of the process of constant-speed gas production under pore pressures of 0.5 MPa, 1 MPa and 5 MPa. The results indicate that the total displacement power of the gas reservoir directly affects the development effect. The higher the pore pressures of the gas reservoir whose part of bound water may flow, the more difficult is the development of the reservoir due to the presence of more movable water, resulting in a poorer development effect. For a lower pore pressure of a gas reservoir, the bound water of the gas reservoir is generally immobile, that is, the gas production is single-phase gas seepage, resulting in an improved development effect. Implementing a reasonable development plan for a water-bearing gas reservoir with low permeability is clearly of great significance to ensure its effective development. Key words: Microscopic model; Constant speed; Gas production; Gas-water saturation; Variation characteristics; Simulation experimen

Automatic Genre Classification via N-grams of Part-of-Speech Tags

AbstractRecurring sequences of words have long been considered as a signifier of different genres and registers by corpus linguists. The previous research mainly focused on lexical n-grams. Nevertheless, n-grams of other linguistic features, such as part-of-speech, have been less studied. The current study is expected to examine whether n-grams of part-of-speech tags extracted from a large corpus can be a discriminator of different genres. The results show that a strong correlation exists between the information about n-grams of part-of-speech tags and the genre of the text

Using MicroPET Imaging in Quantitative Verification of Acupuncture Effect in Ischemia Stroke Treatment

While acupuncture has survived several thousand years’ evolution of medical practice, its function still remains as a myth from the view point of modern medicine. Our goal in this paper is to quantitatively understand the function of acupuncture in ischemia stroke treatment. We carried out a comparative study using the Sprague Dawley rat animal model. We induced the focal cerebral ischemia in the rats using the middle cerebral artery occlusion (MCAO) procedure. For each rat from the real acupuncture group (n = 40), sham acupoint treatment group (n = 54), and blank control group (n = 16), we acquired 3-D FDG-microPET images at baseline, after MCAO, and after treatment (i.e., real acupuncture, sham acupoint treatment, or resting according to the group assignment), respectively. After verifying that the injured area is in the right hemisphere of the cerebral cortex in the brain by using magnetic resonance imaging(MRI) and triphenyl tetrazolium cchloride (TTC)-staining, we directly compared the glucose metabolism in the right hemisphere of each rat. We carried out t-test and permutation test on the image data. Both tests demonstrated that acupuncture had a more positive effect than non-acupoint stimulus and blank control (P < 0.025) in increasing the glucose metabolic level in the stroke-injured area in the brain, while there was no statistically significant difference between non-acupoint stimulus and blank control (P>0.15). The immediate positive effect of acupuncture over sham acupoint treatment and blank control is verified using our experiments. The long-term benefit of acupuncture needs to be further studied

Computational Simulation of Comb-plate Expansion Joints

A finite element model of the expansion Joints’ common damages of a novel comb-plate by using the finite element software ABAQUS is presented in this paper. The mechanical behavior of expansion Joints is analyzed to verify the weak parts of it. The research results provide a reference for the design of the comb-plate expansion Joints

Oceanic internal solitary wave interactions via the KP equation in a three-layer fluid with shear flow

The various patterns of internal solitary wave interactions are complex phenomena in the ocean, susceptible to the influence of shear flow and density distributions. Satellite imagery serves as an effective tool for investigating these interactions, but usually does not provide information on the structure of internal waves and their associated dynamics. Considering a three-layer configuration that approximates ocean stratification, we analytically investigate two-dimensional internal solitary waves (ISW) in a three-layer fluid with shear flow and continuous density distribution using the (2+1)-dimensional Kadomtsev-Petviashvili (KP) model. Firstly, the KP equation is derived from the basic governing equations which include mass and momentum conservations, along with free surface boundary conditions. The coefficients of the KP equation are determined by the vertical distribution of fluid density, shear flow, and layer depth. Secondly, it is found that the interactions of ISW can be carefully classified into five types: ordinary interactions including O-type, asymmetric interactions including P-type, TP-type and TO-type, and Miles resonance. The genuine existence of these interaction types is observed from satellite images in the Andaman Sea, the Malacca Strait, and the coast of Washington state. Finally, the ``bright" and ``dark" internal solitary interactions are discovered in the three-layer fluid, which together constitute the fluctuating forms of oceanic ISW. It is revealed that shear flow is the primary factor to determine whether these types of interactions are ``bright" or ``dark". Besides, a detailed analysis is conducted to show how the ratio of densities influences the properties of these interactions, such as amplitude, angle, and wave width