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The production process of coalbed methane (CBM) includes desorption, diffusion and seepage, and the production is controlled by these three processes together. The permeability of coal reservoir is generally low. To increase the coalbed methane production, well stimulation needs to be applied, in which the contact between fracturing fluid and coal seam is inevitable. Developed micro-fractures, large specific surface area and high capillary pressure of coal generate serious damage easily caused by fracturing fluid, which can affect the production of coalbed methane. Therefore, the multi-scale mass transfer ability damage evaluation method considering CBM desorption-diffusion-seepage capacity was put forward based on the coal reservoir microscopic pore structure and coalbed methane migration output mechanism. Taking the NO.9 coal from Ningwu basin and fracturing fluid in site as the research object, comprehensive damage evaluation experiment of fracturing fluid on CBM desorption-diffusion-seepage were conducted in order to optimizing the fracturing fluid in construction site. Combining the methods of infrared spectrum, wettability, scanning electron microscope and coal mechanical experiments, the impact mechanism of fracturing fluid on CBM desorption, diffusion and seepage were analyzed. Results show that both the coalbed methane desorption rate and the diffusion coefficient of samples treated by fracturing fluid decrease compared with that of treated by formation water; compared with formation water, fracturing fluid can decrease the mechanical strength of coal and strengthen its stress sensitivity, microcracks close further under the action of geostress which will make the flow channel more narrow, eventually the seepage capacity decreases. Through the results of infrared spectrum, wettability and scanning electron microscope we can get the conclusion that fracturing fluid can change the surface structure, wettability and pore connectivity of coal, and affect the migration ability of coalbed methane. The field test of optimized fracturing fluid were conducted, the results are consistent with that of indoor experiment. This study can provide theoretical guidance for fracturing fluid optimization in the operation of coalbed methane wells fracturing.

The traditional highway disease detection technology and method are inefficient and can not meet the needs of modern detection. In this paper, the identification and extraction method of pavement crack disease characteristics is proposed. In the crack disease image, the grey image is transformed to highlight the crack information and background colour. Then, the effects of various image enhancement are compared, and a better algorithm template is selected to remove the black and white noise on the grey image, and the image with high accuracy is obtained. Finally, the image is segmented by stretching threshold, and the crack features are extracted by morphological closed operation. Based on ENVI+IDL development platform, an experimental system for pavement crack disease detection is developed. The experimental results show that the experimental system can effectively detect and extract pavement crack diseases and realize batch processing of multiple disease images.

The Metal Mesh technology with the advantages of low impedance and low cost compared with ITO technology, is widely used in the field of touch area, especially in high‐performance touch field. Because the material is not transparent, the metal touch sensor pattern in the production must be made into fine wire mesh grid, which leads to two problems. One is the Moiré caused by superposition of periodic mesh grid and liquid crystal display RGB arrangement of periodic unit due to beat effect. Since the Mesh grid cycle is not an integer multiple with the pixel cycle, it cannot form the exact same pixel limited by the splicing problem, this will lead to uneven resistance and capacitance in the touchscreen functional area. It is studied on moiré mechanism and the method to solve the moiré by optical simulation and actual attached verification. The study also puts forward a new design of Metal Mesh pattern which makes each pixel exactly same with each other. In result, each Pixel unit is completely symmetrical inside to solve the electrical uniformity problem of Metal Mesh touch screen function area. It is indicated that this pattern design can improve the electrical uniformity and performance of OGM products effectively in the in practical application.