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To clarify the effect and mechanism of hindered amine light stabilizer (HALS) on the UV aging behavior of asphalt binder, T622-HALS was selected as the modifier for UV aging resistance of asphalt. The physicochemical properties and microstructure of T622 light stabilizer were comprehensively analyzed. The light stabilizer-modified asphalt was prepared and placed in the UV radiation chamber for UV aging treatment. Scanning electron microscope and atomic force microscope were used to analyze the microscopic morphology evolution of light stabilizer-modified asphalt induced by UV radiation. The thermal properties and functional group composition changes in light stabilizer-modified asphalt during UV aging were studied by using the thermogravimetric and infrared spectroscopy combined testing system. The decay laws of the physical and rheological performances of light stabilizer-modified asphalt were studied during UV aging process, and the effect of light stabilizer on the UV aging behavior of asphalt binder was clarified. The research results indicated that HALSs could alleviate the microcracks and roughness change on the surface of asphalt and reduce the content of functional groups such as carbonyl and sulfoxide in asphalt. Furthermore, HALS could reduce the value difference of physical and rheological properties of asphalt before and after UV aging, significantly improving the UV aging resistance of asphalt binder.

Objective: To apply evidence-based medicine for systematically evaluating the risk factors for dysphagia after anterior cervical spine surgeries. Methods: Relevant papers included were retrieved with a time range from the establishment of the databasis to July 1st, 2023 from databases including CNKI, CBM, VIP, Wanfang database, The Cochrane Library, Embase, PubMed and collected case-control studies and cohort studies of risk factors for dysphagia after anterior cervical spine surgeries. Newcastle-Ottawa Scale was used to extracted research data and evaluated the quality of the included literature, then use the Rev-Man5.4 statistical software for meta-analysis evaluation. Results: A total of 29 papers and 7 487 patients were included in this analysis, 1 640 patients of whom developed dysphagia. And the Meta analysis of the data showed that female [OR=2.93, 95% CI (2.45, 3.51), P<0.000 01], age[MD=5.82, 95% CI(3.91, 7.73), P<0.000 01], smoking[OR=2.48, 95% CI(1.89, 3.27), P< 0.000 01], diabetes [OR=2.41, 95% CI(1.41, 4.12), P=0.001], surgical level≥2 level[OR=2.10, 95% CI(1.73, 2.56), P< 0.000 01], surgical segment location [OR=2.21, 95% CI(1.64, 2.98), P<0.000 01], operation time [MD=24.73, 95% CI (14.66, 34.79), P<0.000 01], use of plate [OR=5.93, 95% CI(3.62, 9.71), P<0.000 01], postoperative prevertebral soft tissue swelling [MD=1.77, 95% CI(0.04, 3.50), P=0.04], dC2-7Cobb angle[MD=2.36, 95% CI(1.34, 3.37), P<0.000 01] are risk factors for dysphagia after anterior cervical spine surgeries; preoperative tracheal stretch exercise [OR=0.26, 95% CI(0.17, 0.41), P<0.000 01] are protective factors for dysphagia after anterior cervical spine surgeries; there was no statistically significant association between postoperative 0-C2 angle [MD=-1.65, 95% CI(-5.05, 1.76), P=0.34], postoperative C2-7Cobb angle [MD =3.45, 95% CI(-0.07, 6.98), P=0.05] and dysphagia after anterior cervical spine surgeries.Conclusion; Female, age, smoking, diabetes, surgical level≥2 level, surgical segment location, operation time, use of plate, postoperative prevertebral soft tissue swelling, and dC2-7Cobb angle are risk factors for dysphagia after anterior cervical spine surgeries, preoperative tracheal stretch exercise is protective factor for dysphagia after anterior cervical spine surgeries. According to these factors, doctors can communicate with patients about the possibility of postoperative dysphagia in advance, prevent postoperative dysphagia and reduce the occurrence of postoperative dysphagia. [ABSTRACT FROM AUTHOR]

At present, there are a variety of coal gangue identification technologies in automatic top coal mining. Gamma ray is too expensive and harmful to human body. Infrared technology is affected by ambient temperature. Radar detection has serious signal attenuation when the coal seam is thick. Sound technology has low cost and small difficulty, but can be severely interfered by external sound signals. Image technology is effective when the color difference of coal gangue is large, but is affected by dust and light factors. However, vibration technology not only has the advantages of sound technology but also can avoid environmental noise interference and obtain a higher detection accuracy. For the properties of top coal and gangue are different, the vibration signal generated when falling onto the hydraulic support tail beam also shows different characteristics. Based on this feature, a vibration sensor is designed, which is installed at the web of the tail beam of the hydraulic support to sense the vibration signal generated by the top coal or gangue hitting the hydraulic support, and identify the coal and gangue in the coal release process through signal processing and analysis. The sensor uses an accelerometer to collect the tail beam vibration signal, and conducts front-end filtering processing of the collected data. Fourier transform is applied to analyze the power spectrum of the data so as to obtain the maximum vibration frequency, amplitude and power spectrum energy per unit time. The laboratory test results show that the sensor measurement error is within 1%. The underground test results show that most of the signals collected by the vibration sensor are the vibration signals of coal falling, and the frequency range is 100-200 Hz. However, the vibration signals of gangue falling is above 200 Hz. Therefore, the differences of the vibration signal characteristics are useful to identify the top coal and gangue.

In order to solve problems of high development cost, large maintenance and difficult cross-platform transplantation of existing coal mine roadheader control system taking ordinary PLCs and dedicated controllers as cores, a roadheader control system based on embedded soft PLC technology was designed. The functional requirements and implementation principles of the system were analyzed. The control system architecture taking embedded soft PLC as the core was put forward. The system realizes basic logic control, full-function remote control and automatic cutting function of the roadheader through the customization of real-time operating system, transplantation of the soft PLC runtime system and the development of the drive components. The system also can real-time monitor status of the roadheader, and can realize full-function remote control through the remote control, automatic cutting and shaping of the roadway section by setting parameters such as section shape, path type, roadway height, roadway width and cutting interval. Compared with the control system with PLC and dedicated controller as the core, the roadheader control system based on embedded soft PLC can better realize unified standard and system's configuration and development of roadheader equipment, which has good cross-platform portability.The test results show that basic control function and remote control operation of the system are good, and the maximum error of automatic cutting surface boundary is less than 10 cm.