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Cardiopulmonary exercise testing (CPET) refers to a method of measuring various indicators of the human body under gradually increasing exercise loads to objectively evaluate cardiopulmonary reserve function and exercise endurance. Currently, CPET detection systems primarily measure subjects' ECG, respiratory flow, oxygen (O2), and carbon dioxide (CO2) parameters. This paper introduces a non-invasive multi-parameter exercise cardiopulmonary function evaluation system that incorporates impedance cardiography monitoring. The system integrates impedance cardiography monitoring with conventional CPET detection parameters and detects changes in the hemodynamic parameters of the body during exercise, aiding in the evaluation of exercise capacity. Additionally, the system features a portable design with Wi-Fi wireless transmission, which enhances its applicability.

To screen eminent litchi varieties suitable for the development of natural antioxidant products, the total phenol, total proanthocyanidin, total flavonoid contents and A-type oligomeric procyanidin fractions in the pericarps of seven diverse litchi cultivars were analyzed. The in vitro antioxidant activities including DPPH, ABTS+ free radical scavenging and FRAP were determined. The results demonstrated that the total phenols, total proanthocyanidins, total flavonoids as well as total A-type oligomeric procyanidins contained in the pericarp extract of 'Hemaoli' were the highest. In addition, the primary and secondary mass spectra of the contained substances were analyzed and identified by electrospray liquid-mass spectrometry with quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS/MS). The mass spectrometry results demonstrated that the oligomeric procyanidin fractions contained in litchi pericarps were mainly epicatechin, procyanidin A2, procyanidin A4, A-type trimer and tetramer. Moreover, the content of A-type oligomeric procyanidins in litchi pericarp varied significantly (P

How to achieve intelligent, safe and efficient mining of rockburst coal seams is a major engineering and technical challenge facing deep coal mining. The core connotation of this issue lies in the intelligent, unmanned, and inherently safe mining of coal seams with rockburst. Through accurate perception and intelligent early warning of coal and rock burst risks, as well as self-adaptation and self-optimization of mining engineering, intelligent anti-burst and mining control technologies are formed to achieve a fundamental shift from engineering-induced disasters to engineering-prevented and mitigated disasters. By implementing measures such as mining source design, roof area fracturing, localized targeted management, and strengthening roadway support, a low-stress environment and safe roadway space are created for the safe and efficient mining of coal seams with rock burst. On this basis, a big data analysis software platform that integrates static geological, dynamic monitoring, working conditions, personnel positioning, production organization, historical data and other information, as well as an intelligent mining control system that integrates impact pressure decision-making information, has been developed. The anti-impact information source has been transformed into an intelligent mining control source, forming a new flexible intelligent mining model of "low pressure fast pushing, medium pressure slow mining, and high pressure production stop". Field application shows that in the intelligent anti-impact and control mining area, the degree of mine pressure in working face and roadway is smaller,, and the energy release of coal and rock is more stable, which is conducive to the reasonable release of impact mine production capacity.

Recently, lithium-ion capacitors (LICs) have developed rapidly and have been applied in many fields, such as power storage and new energy transportation. LICs utilize the cathode materials of electrical double-layer capacitors (EDLCs) and the anode materials of lithium-ion batteries (LIBs). This produces a unique energy storage mechanism different from those of LIBs and EDLCs, i.e., charge transfer and Li+ insertion and desorption. Consequently, LICs combine the advantages of LIBs and EDLCs with high energy density, high power density, and long cycle life. However, because of this unique energy storage protocol, LICs inherit the poor low-temperature performance of LIBs, severely limiting their widespread application. Sometimes, the electrolyte becomes more viscous or even solidifies, affecting normal ion transportation and charge transfer. An increase in impedance prevents the normal operation of LICs, severely limiting their all-weather applications. Improving the low-temperature performance of LICs has become an urgent issue and has received widespread attention from researchers. Electrodes and electrolytes are the main components of LICs, and numerous studies have shown that their relationship directly determines the energy storage process of LICs at low temperatures. Therefore, this article reviews the recent research progress on the design and fabrication of low-temperature LICs in terms of electrodes and electrolytes. First, the research on key electrode materials for high-performance low-temperature LICs is discussed, including chemical modification, surface modification, ion insertion, and the development of new electrode materials for rapid intercalation of traditional carbon-based materials. Second, the electrolyte system that matches the electrode material is critically reviewed. The fundamental reasons for the poor performance of LICs in low-temperature environments are comprehensively explained from the chemical properties, physical states, and reaction mechanisms, providing a sufficient theoretical basis for searching electrolyte systems with better low-temperature performance. Third, starting from the main components of the electrolyte–lithium salts, solvents, and additives, this article summarizes the past year’s progress on low-temperature electrolytes in LICs. Emphasis is placed on additives for LIC electrolytes, which, as the essence of the entire electrolyte system, are the most controllable factor throughout the electrolyte system and currently the most available factor for selection. They can reduce the viscosity of the electrolyte with minimal content and improve the low-temperature charging and discharging ability of LICs. Commonly used low-temperature additives such as fluoroethylene carbonate (FEC), vinylene carbonate (VC), ropylene sulfite (PS) and lithium difluorooxalate borate (LiODFB) demonstrate excellent low-temperature performance. Finally, the article summarizes the research progress of the new generation of low-temperature electrolytes and provides a tentative outlook toward next-generation LICs with a wide temperature range.

ObjectiveTo understand the pneumococcal vaccination status and its influencing factors among young and middle-aged populations, and provide reference for promoting pneumococcal vaccination. MethodsFrom May to August 2023, a multi-stage random cluster sampling method was used to select 5 928 residents aged 19 – 59 years old from Nanchang city in Jiangxi province, Changsha city in Hunan province, and Kunming city in Yunnan province for an online questionnaire survey on pneumococcal vaccination status. ResultsAmong the 4 895 young and middle-aged people finally included in the analysis, only 833 had received pneumococcal vaccine in the past 5 years, with a pneumococcal vaccine uptake rate of 17.02%; multivariate unconditional logistic regression analysis showed that the pneumococcal vaccine uptake rates were higher among those aged 45 – 59 years old, agriculture, forestry, animal husbandry and fishery production personnel, professional and technical personnel, smokers, those with general knowledge of pneumococcal diseases and vaccines, and those with general and good trust in pneumococcal vaccines, while the uptake rates were lower among those with high school/technical secondary school education or above and office clerks and related personnel; the top three reasons for pneumococcal vaccination among young and middle-aged people were disease prevention (75.87%), protecting family and colleagues (57.38%), and government and health administration recommending vaccination (43.22%), while the top three reasons for not receiving pneumococcal vaccine were worrying about adverse reactions after vaccination (42.22%), no time for vaccination (28.19%), and believing that the vaccine had limited effectiveness (25.11%), and the top three factors most likely to change vaccination willingness were free/discounted vaccines (46.63%), worrying about the impact of pneumonia infection on family and colleagues (46.53%), and government and health administration recommending vaccination (45.89%). ConclusionThe pneumococcal vaccine uptake rate among young and middle-aged populations was low, and age, education level, occupation, smoking status, knowledge of pneumococcal diseases and vaccines, and trust in vaccines was the main influencing factors for pneumococcal vaccination in this population. Comprehensive policy measures, especially the introduction of preferential policies related to pneumococcal vaccines, should be adopted to promote vaccination.

The northwestern region in China has the characteristics of large coal seam thickness and shallow burial depth. Unmanned aerial vehicle (UAV) thermal infrared monitoring and temperature compensation are key technologies for monitoring shallow coal fire disasters, which is of great significance for advancing the safety monitoring and warning evaluation of coal spontaneous combustion disasters. A temperature compensation model based on the grey wolf optimization-double-layer generalized regression neural network (GWO-double-layer GRNN) and continuous altitude correction function is proposed to address the influence of multiple parameters on thermal infrared temperature monitoring results in complex environments. The factors affecting the temperature results under the thermal infrared monitoring band are selected based on the contrast of the atmospheric extinction coefficient to the received radiation, and the index factors that can cumulatively characterize the actual temperature are determined by principal component analysis. The index factor data from the UAV thermal infrared monitoring experiments in various environments are used as inputs to the GWO-double-layer GRNN network to obtain a discretely trained temperature compensation model. A continuous correction function for UAV altitude is proposed as a pre-processing step for the model input to compensate for the data, and the complete temperature compensation model is tested and field-validated. The results show that the discrete compensation effect of the GWO-double-layer GRNN network is superior to other models in data testing, with MAE ≤ 0.008 1, RMSE ≤ 0.013 2, and R2 ≥ 0.996 9, indicating that the model has good compensation effects. The continuous correction function avoids the influence of UAV altitude on thermal infrared monitoring results, dividing the problem of UAV continuous altitude thermal infrared temperature regression into a stepwise regression calculation, and the final model has a good monitoring accuracy, improving the generalization ability of the temperature compensation model. It provides a supporting calculation method for applying UAV thermal infrared monitoring results to delineate shallow coal fire hazard areas and further promote this method to the corresponding UAV applications and laser monitoring industry.

ObjectiveThis paper proposes a novel structure that combines an offshore wind turbine jacket and aquaculture net cage, and its hydrodynamic characteristics are investigated. Methods Experimental tests are carried out to analyze the horizontal loads on the pile foundations of the combined structure, and the tension in the connection between the jacket and net cage, while considering the effects of water depth, wave height, wave period, wave direction, current velocity and direction, and other parameters. ResultsFor 0-degree regular wave conditions, the maximum horizontal load on the pile foundations is 30.2 N. For 45-degree regular wave conditions, the maximum horizontal load on the pile foundations is 27.5 N. Thus, the maximum horizontal load on the pile foundations under 0-degree regular wave conditions is 9.5% greater than that under 45-degree regular wave conditions. ConclusionsUnder regular wave conditions, the net cage has little influence on the horizontal load on the pile foundations when the wave period is small, while under pure current conditions, the net cage will cause a significant increase in the horizontal load on the pile foundations of the combined structure.

The development height of water-conducting fracture zone(WCFZ) is an important parameter for water disaster treatment in coal mine roof. In this paper, the failure process of mining overlying rock is analyzed, and the rock instability failure in the fracture zone is divided into three stages: vertical fracture formation, masonry structure formation and gyratory instability; a mechanical model of vertical cracks and gyration subsidence is established. On this basis, the maximum subsidence of vertical cracks and gyration instability is analyzed to judge the rock failure. The rock stratum with gyration subsidence value between these two stages forms a stable masonry beam structure, and a new method for calculating the height of WCFZ is obtained. Taking the 2201 working face of Yingpanhao as an example, the height of the WCFZ is predicted by theoretical method and numerical simulation. By comparing with the field measured data, the theoretical calculation (123.3 m) and numerical simulation results (132 m) are close to the measured data (115.5 m), which verifies the rationality of the proposed method.

Studying the variation characteristics and main influencing factors of PM2.5 concentration in the Yangtze River Basin from 2016 to 2021 could provide references for optimizing the policy of collaborative governance of the atmospheric environment in the basin. Using the PM2.5 concentration data from 110 national stations in the Yangtze River Basin from 2016 to 2021, the temporal and spatial variation characteristics of PM2.5 were analyzed with the Theil-Sen trend analysis and Mann-Kendall statistical test methods. Combined with the Environmental Meteorological Assessment Index (EMI), the relative contributions of the two main influencing factors including the meteorological conditions and emission reduction measures, to the changes in PM2.5 concentration changes during the "13th Five-Year Plan" period (2016—2020) and the first year of the "14th Five-Year Plan" (2021) were quantitatively analyzed. The results were as follows. (1) Significant spatial variations in PM2.5 concentration distribution were found in the Yangtze River Basin was uneven in 2016-2021. The high-value areas were in the eastern part of the Hanjiang River Basin extending southward to the eastern part of the Dongting Lake Basin and the southern part of the Mintuo River, While the low-value area was in the upper and middle reaches of the Jinsha River Basin. (2) During the "13th Five-Year Plan" period, PM2.5 concentration in major cities of the Yangtze River Basin decreased year by year, with an annual variation rate of -3.62μg·m-3·a-1. However, PM2.5 concentration about 40% of the Yangtze River Basin region increased in 2021, which was mainly distributed in the upper reaches of the Yangtze River Basin and Dongting Lake Basin. (3) The PM2.5 in the western part of the basin was greatly affected by meteorological conditions, while the eastern part was greatly affected by emission sources and other factors. (4) Meteorological conditions and emission reduction measures during the "13th Five-Year Plan" period were conducive to the decrease of PM2.5 concentration.Their contribution rates to the increase of PM2.5 were -16.54% and -14.00%, respectively. Compared with the previous year, the emission reduction measures in 2021 were generally beneficial to the decrease of PM2.5 concentration (contribution rate of -5.84%), but adverse meteorological conditions (contribution rate of 4.49 %) offset part of the emission reduction effects, making a slight decrease in the PM2.5 concentration.

Although blood banks based on human blood can provide blood transfusions for the wounded timely and effectively, scientific research has never given up on finding new blood sources due to the restrictions of human blood sources. With the application of transgenic technology and the successful breeding of gene-edited pigs, gene-edited pig blood as a potential source of clinical transfusion has attracted wide attention. Now there are preclinical studies showing the feasibility of transfusing gene-edited pig red blood cells into primates. This paper discusses the related research and future development of xenogeneic transfusion of porcine red blood cells by gene editing.

CO2 geological storage is a guaranteed technology for achieving carbon neutrality. The offshore deposit basin is far away from the human activity area, and the implementation of a CO2 geological storage is more advantageous than the land sedimentary basin. To find out the CO2 storage potential in the Weixinan sag of the Beibu Gulf Basin, based on the 8 indicators such as caprock burial depth, the maximum thickness of single layer mudstone, mud-soil ratio, fault density and reservoir porosity, formation thickness, sand-soil ratio, permeability, etc., it has established a reservoir evaluation system for the secondary structure unit of the basin. Combined with the core physical property data of lays and 3D geological models, the reservoir and caprock of the Weixinan sag are optimized, and the effective storage potential is evaluated with the US-DOE method. The results show that within 800−3000 meters below the sea floor, in the Weixinan sag, there are two sets of reservoir-cap combinations suitable for CO2 storage. Combination 1: in Neogene, the neritic mudstone of the first member of the Jiaowei Formation is the cap rock, and the neritic sandstone of the second member of the Jiaowei Formation and the Xiayang Formation is the reservoir, and the effective storage capacity is 0.749 billion tons. Combination 2: in the Paleogene, the deep lake mudstone in the second member of the Weizhou Formation is the cap rock, and the sandstone in the third member of the Weizhou Formation is the reservoir, and the effective storage capacity is 0.374 billion tons. In the Weixinan sag, two sets of reservoir-cap assemblages suitable for CO2 storage in the saline aquifers are selected, with an effective storage capacity of 1.123 billion tons. According to the evaluation of the annual CO2 emission of 70 million tons in the west of Guangdong Province, it can meet the CO2 emission reduction needs of the region for more than 16 years. Offshore geological storage is a potential path for the green and sustainable development of coastal heavy chemical clustering areas and to achieve the goal of carbon neutrality.

To enrich the research methods for studying the development law of bed separation, this paper takes the upper 08 working face of 221 in Shilawusu Mine as the research object, and comprehensively determines the location of bed separation through distributed optical fiber (BOTDR) and fixed-point optical fiber. The particle flow code (PFC2D) is used to study the pattern of the separation layer development under the conditions of large mining height and large mining depth. The results show that, as the working face advances away from the cutting hole, the separated layer develops intermittently from the bottom to the bottom of the key layer, and the depth of separation layer development is around 440 m, 396 m, 376 m, 331 m, 321 m and 296 m, and the layer stops at the bottom of the main key layer of coarse sandstone. The overburden transport mainly goes through the stages of subsidence of the lower key layer, rapid subsidence of the upper sub-key layer, development of overburden movement towards the bottom of the main key layer of coarse sandstone, and transport of the main key layer. The separated layer position is proportional to the advancement distance of the working face, and the development of the separated layer is mainly divided into three stages, which are gestation (Ⅰ)-accelerated expansion (Ⅱ)- compression stage (Ⅲ).

This study aimed to investigate the differences in volatile composition and aroma of different fractions of Osmanthus fragrans absolute purified by molecular distillation. Gas chromatography-mass spectrometry (GC-MS) combined with orthogonal partial least-squares discrimination analysis (OPLS-DA), P-value, variable importance in the projection (VIP), and relative odor activity value (ROAV) were used for analysis. The light, heavy, and residue fractions of Osmanthus fragrans absolute were analyzed. A total of 73 volatile components belonging to 8 major categories were detected in the three fractions, including 22 alcohols, 5 aldehydes, 10 acids, 3 phenols, 5 ketones, 17 esters, 5 alkanes, and 6 olefins. Alcohols were the main contributors to the volatile components in each fraction, and the types and relative contents of volatile components significantly differed among the fractions (P1) of the three fractions, the key aroma contributing components (ROAV>1) of the 14 light fractions, 9 recombinant fractions, and 11 residue fractions were analyzed by the aroma profile analysis. Light fractions exhibited more intense floral, sweet, and pine woody aromas compared to recombinant and residue fractions. The light fractions had the highest types and relative contents of volatile components and showcased the most intense Osmanthus fragrans floral flavor. This study provided a theoretical basis for the comprehensive utilization of different fractions of Osmanthus fragrans absolute through molecular distillation using GC-MS combined with chemometrics methods.

Objective To evaluate the feasibility of AIMS65 score combined with neutrophil-to-lymphocyte ratio(NLR) in predicting in-hospital death from esophageal and gastric variceal bleeding(EGVB) in cirrhosis in order to assist clinical patient management. Methods A total of 326 patients with EGVB due to liver cirrhosis who were hospitalized in Taizhou People′s Hospital Affiliated to Nanjing Medical University from January 2018 to October 2022 were selected as the study subjects.According to the outcome during hospitalization, 33 patients were divided into death group and 293 patients into survival group.The clinical data of all patients were collected by electronic medical records, and multivariate logistic regression was used to screen the independent risk factors for in-hospital death in cirrhotic EGVB patients;ROC curve was used to analyze the clinical value of AIMS65 score combined with NLR at admission in predicting in-hospital death in EGVB patients. Results Univariate analysis showed that there were significant differences in albumin, NLR, and AIMS65 scores between the two groups(P

During deep coal mining processes, periodic mining disturbances cause the neighboring coal strata to bear the effects of cyclic loading and unloading, making it essential to study the mechanical responses and macro-micro failure characteristics of the coal-rock composite structures under different cyclic loads. In this study, three different loading rates were selected to perform uniaxial cyclic compression tests (with simultaneous acoustic emission signal measurement) under two types of cyclic loads, investigating the damage characteristics of coal-rock composites. Based on the principle of energy dissipation, an energy-damage constitutive model for the cyclic loading of composites was constructed and validated with experimental data. The results indicate that the loading rate is directly proportional to the peak strength of the composite specimen, where the peak stress increased by 22.44% and 28.89% for the gradual cyclic loading and unloading path (path I) and the cyclic loading and unloading path (Path II) respectively. The higher the loading rate, the faster the internal crack extension in the specimen, the crushing degree of the coal component in the coal-rock composite specimen is intensified, and the fractal dimension increases subsequently, and the faster the internal crack extension in the specimen becomes. With the increase of the loading rate, the damage along the matrix in the coal fraction increases. The paths with a large span of cyclic gradation (Path I) contribute to stress transfer within the specimen and provide favorable conditions for the development of cracks within the specimen, leading to a higher degree of damage in the corresponding specimen. The consistency between the test curves and the energy-damage constitutive model curves is relatively high, indicating that the proposed energy-damage constitutive model can well describe the deformation behavior of the coal-rock composite specimens during cyclic loading and unloading processes.

In order to study the yield stress and thixotropic behavior of the hydroxypropyl distarch phosphate (HPDSP) paste, HPDSP respectively derived from corn starch (CS) and waxy corn starch (WS) with different ratios of amylopectin were investigated. The critical mass fractions, yield stress, and thixotropic behavior of HPDSP pastes under various temperatures were studied. The results showed that, the critical mass fractions for the transition of the HPDSP solution at 5 ℃ from dilute to semi-dilute, and from semi-dilute to concentrated were 3wt% and 6wt%, respectively. The yield stress of 5wt% corn starch-hydroxypropyl distarch phosphate (CS-HPDSP) and waxy corn starch-hydroxypropyl distarch phosphate (WS-HPDSP) paste both showed weak correlations with temperature. However, at 6wt% concentration, the yield stress significantly decreased (P

Spontaneous combustion of coal increases the risk of fires during its storage and transportation, posing a challenge to the sustainable development of the coal industry. This study employs various similarity criteria, including geometric, time, kinematic, dynamical, Euler’s, Strohal’s, Vernold’s, and Reynolds’ criteria, to investigate the rules of the spread of loose coal body combustion under wind flow conditions using a self-built, open-vehicle coal transportation simulation experimental device. The device recreates the temperature rise process in loose coal bodies, the formation of high-temperature areas, and their subsequent spread. It also analyzes the internal high-temperature area spread and gas distribution rules under wind flow. During the experiment, the temperature of each measurement point changed as the constant temperature time increased, with the measurement points closer to the heat source showing a significant temperature increase compared with those farther away. The experiments were conducted for 70, 54, and 48 h under wind flows of 0, 1, and 2 m·s−1, respectively. The results reveal that the crosswind flow on the surface significantly accelerates the spread of the seed of coal sample combustion. Compared to wind flow at 0 m·s−1, the high-temperature area spread time is 0.3 times quicker (wind flow at 1 m·s−1) and 0.5 times quicker (wind flow at 2 m·s−1); moreover, the maximum temperature of the high-temperature area increases by 120 ± 20 ℃, eventually stabilizing at 510 ℃–560 ℃. The spreading path of the high-temperature area drifts toward the wind under the influence of crosswind flow on the surface. When the wind flow is 0 m·s−1 the difference between the time when the CO concentration peaks at the critical point of each layer and when the critical point reaches 300 ℃ (Δh1) gradually increases with the number of layers. However, under the effect of wind flow, Δh1 is maintained at 1.4 ± 1 h (wind flow at 1 m·s−1) and 0.9 h (wind flow at 2 m·s−1), thus intensifying the coal–oxygen reaction and causing the combustion to spread more rapidly. For each critical point of the oxygen volume fraction of the layers, the time elapsed during the rapid decline phase of the O2 volume fraction at the high-temperature point of combustion gradually increases with depth. When the wind flow is 0 m·s−1, the difference between the time to reach the limiting O2 volume fraction at the critical point and the time to reach 300 ℃ at the critical point (Δh2) increases with depth. However, under the effect of wind flow, Δh2 is maintained at 0.6 ± 0.3 h (wind flow at 1 m·s−1) and 1 ± 0.2 h (wind flow at 2 m·s−1), indicating that surface airflow can exacerbate the rate of O2 consumption during the downward spread of high temperatures. Therefore, controlling air leakage can delay the spread of coal fires. These findings offer valuable insights for developing guidelines to control coal fires during coal transportation and storage.

Air leakage is an important cause of coal spontaneous combustion in mines, which affect the normal production of the mine. In order to solve the problems of long gelling time and weak stacking ability of traditional inorganic solidified foam (TISF) in the process of filling and plugging, a rapid setting inorganic solidified foam (RISF) modified by liquid sodium silicate (LSS) was proposed. The influence of different dosages of LSS on the gelling time, stacking capacity and other properties of foam slurry was studied. By means of compressive strength, stability test and other characterization methods, the optimal addition amount of LSS was determined to be 5% (mass fraction). The 28 d compressive strength of RISF reached 2.49 MPa, 1.7 times that of TISF. The maximum density ratio R was 1.11, and the stability increased by about 20%; The test results of gelation time and stacking ability showed that compared with TISF, the setting time of RISF was significantly shortened (from 683 s to 52 s), and the stacking ability was improved (the maximum stacking height is increased by 1.9 times). Based on this, the rapid curing mechanism of RISF was explored by combining scanning electron microscope (SEM) and X-ray diffraction (XRD). The test results showed that RISF had more hydration products and different hydration products were closely intertwined. During the particle hydration process, LSS hydrolyzed to generate the orthosilicate and combined with calcium ions in the solution, which accelerated the hydration reaction and shortened the gelling time of foam slurry. However, it was also found that when the amount of LSS added exceeded 5%, the compressive strength and stability of RISF decreased. This is mainly because excessive LSS caused the calcium silicon ratio in the solution to be lower than 1.0, resulting in the formation of low strength hydration products. The results of air blockage and fire extinguishing tests showed that compared with TISF, RISF had higher air blockage efficiency and excellent fire prevention and extinguishing performance, with a maximum increase of 26.3% in blockage efficiency, and no reignition occurred when extinguishing coal fires. The on-site application of RISF in the gangue hill of Limin Coal Mine has shown that it has good cooling and fire extinguishing effects, effectively solving the high temperature problem of the gangue hill, and ensuring the normal production of the mine.

In order to strengthen the construction of mine fire intelligent monitoring and early warning system, the research idea of mine fire intelligent monitoring and early warning technology, and summarizes the research progress of mine fire intelligent monitoring and early warning technology is put forward. The research progress from three aspects of mine fire intelligent perception technology and equipment, prediction technology and modeling, and intelligent early warning system and platform is summarized. First, the internal and external cause fire information monitoring technology and equipment are summarized, the recognition process based on image-video recognition is summarized, and the content of multi-source information fusion and its application in the fire monitoring process are described. Secondly, the prediction techniques and models for mine fires are introduced, including machine learning algorithms such as support vector machine, artificial neural network, and random forest algorithms. Then, the mine fire early warning system and platform are elaborated. On the basis of summarizing the graded early warning technology for spontaneous coal combustion and exogenous fires in mines, the progress of the mine fire early warning system platform in terms of perception layer, network layer, service fusion layer and application layer is introduced. The connotation of each layer of the early warning system and the application framework are summarized, and the intelligent monitoring and early warning system for fires in mines is constructed. Finally, the future development trend of mine fire intelligent monitoring and early warning technology in China is outlooked including following aspects. In terms of intelligent perception technology of mine fire information, it is proposed to strengthen the research and development of sensing technology and equipment. In terms of intelligent prediction technology for mine fires, it is proposed to strengthen the research on the location exploration method of hidden fire sources and construct a transparent model of fire disasters. In terms of the construction of an intelligent early warning system for mine fires, it is proposed to integrate big data into intelligent judgment, identify the risk sources of mine fire and forecast the sources’ location of hidden fire, and realize the early warning of spontaneous coal combustion under special conditions. In terms of the linkage between the intelligent judgment and prevention and control technology for mine fires, it is proposed to utilize large-scale linguistic models to realize the self-adaptive prevention and control of mine fires on the basis of intelligent judgment.

To meet the requirements of autonomous detection of underwater moving targets in a strong reverberation background, a track initiation algorithm based on multiple accumulations of active sonar images was proposed to solve the problem of large amounts of data after space-time processing of active sonar echo signals. Firstly, the underwater multi-target track initiation model in the strong reverberation background of the active sonar was constructed. The range-azimuth-frame time three-dimensional sonar image was condensed into the range-azimuth two-dimensional sonar image by selecting the largest data of sonar images, and the accumulated frame information was retained. The measurement information and energy information of the target were obtained through the centroid clustering point extraction method, and the data preprocessing was completed. Secondly, the energy was accumulated in the parameter space of the Hough transform, and the initial track of multiple targets was obtained by the method of local peak detection. Finally, in order to improve the accuracy of the track, the reverberation and duplicate tracks were eliminated by using the velocity constraint and track merging method. The simulation results show that compared with conventional target tracking methods, this algorithm can effectively reduce the amount of sonar image data in the course of track initiation and can still achieve autonomous detection of underwater multiple targets with high detection probability in a strong reverberation background.

The evaluation of grouting effect is one of the crucial links in grouting water control project. As grouting technology matures, traditional methods of evaluating grouting effects are more subjective and fewer objective, which leads to the drawback that the evaluation results deviate from reality. Taking the grouting project of 8901 working face in Baizhuang Coal Mine of Shandong Province as the background, combining existing research and field experience, the grouting final pressure, permeability coefficient, water absorption rate and the number of dry material per ton of water are selected as the evaluation indexes, and the comprehensive evaluation system of grouting effect is established. Based on the comprehensive evaluation theory, a comprehensive subjective and objective weighting method is proposed, which based on analytic hierarchy process(AHP) combined with CRITIC objective weighting method. And the objectivity ofpf indicator assignment is improved by combining subjective and objective weights. Based on the combination weighting method, a comprehensive evaluation model of grouting effect is established, which is sorted by technique for order preference by similarity to an ideal solution (TOPSIS) and assisted by rank sum ratio (RSR). The evaluation results are converted into visual partition maps and compared with the actual evaluation results of field engineering and the results of the testing process after grouting, and the results show that the model has superior accuracy and rationality.

Purposes Methane dehydroaromatization (MDA) is a frontier topic in the field of natural gas chemical industry. Methods Mo/commercial-HZSM-5, Mo/nano-HZSM-5, and Mo/hollow capsule HZSM-5 were synthesized by using a conventional wet impregnation strategy. The samples were characterized by ICP, XRD, BET, SEM, TEM, NH3-TPD, and XPS, and tested in MDA reaction. The properties of carbonaceous species were measured by TG and TPO techniques. The carbon cycle path was investigated through periodic 12CH4/13CH4 isotope switch pulse experiment over Mo/hollow capsule HZSM-5 catalyst during MDA reaction. Findings The active carbonaceous species located inside the pores could take part in the formation of benzene. Among these three Mo-based catalysts, the Mo/hollow capsule HZSM-5 showed higher CH4 conversion and aromatic yield, as well as superior catalytic lifespan. Compared to Mo/nano-HZSM-5 in zeolite particle size and acidity, Mo/hollow capsule HZSM-5 with lower deactivation rate is attributed enhanced gas molecules diffusion in its hollow capsule structure.

In order to improve the yield of bacterial cellulose (BC), the fermentation medium of the Gluconacetobacter xylinus was optimized by response surface methodology. Based on the optimization results, the effects of sodium alginate (SA), sodium carboxymethyl cellulose (CMC-Na) and carboxymethyl cellulose (CMC) on the yield of BC, total sugar consumption, acetic acid and pyruvic acid were investigated. The results showed that when the amounts of addition of glucose was 4%, yeast extract powder was 1%, peptone was 0.8%, MgSO4 was 1.9%, Na2HPO4 was 0.2%, acetic acid was 0.4%, ethanol was 1.6%, the actual yield of BC could reach 5.19 g/L. After adding SA, CMC-Na and CMC, the total sugar consumption increased by 29.9%, 22.82% and 15.73%, and the yield of BC was 6.72, 6.01 and 5.1 g/L, respectively. The content of pyruvic acid in SA group and CMC-Na group was increased by 29.02% and 16.52% compared with the control group. SA and CMC-Na promoted the accumulation and utilization of pyruvate acid, the yield of BC accumulation was increased. The highest acetic acid accumulation (4.27 g/L) was observed in the CMC addition group, which had a certain relationship to the lower yield of BC than the control group.

The injection of CO2 into deep unrecoverable coal seams is one of the effective ways to achieve CO2 geological sequestration, but CO2 will be in a supercritical state under the action of high pressure and high temperature. In order to investigate the effect of supercritical CO2 action on coal reservoir structure, based on the self-developed supercritical CO2 immersion experimental system, combined with acoustic emission test system and RFPA3D numerical simulation, we studied the three coal seam thicknesses and three top and bottom lithologies of the mechanical damage characteristics and the fracture extension evolution of “Rock-Coal-Rock” (RCR) composite specimens under the action of supercritical CO2 were investigated. The results show that: ① After the action of supercritical CO2, the degradation of compressive strength and elastic modulus of the RCR composite gradually increases and decreases with the increase of coal thickness, while the degradation of compressive strength and elastic modulus are basically the same when the strength ratios of rock and coal are different and do not show large differences; ② The action of supercritical CO2 will promote the plastic damage of the coal body and intensify the transformation of the RCR composite from tensile splitting damage to shear plastic damage, and the degree of plastic damage of RCR assemblage is positively correlated with both coal thickness and rock-to-coal strength ratio; ③ The supercritical CO2 immersion promoted the RCR assemblage to enter the elastic deformation stage earlier, and the destabilization damage occurred after a more brief elastic deformation, the greater the coal thickness, the greater the influence, while the rock-to-coal strength ratio has less influence; ④ The instability potential of RCR assemblage is proportional to coal thickness and inversely proportional to rock-coal strength ratio, and the power intensity of damage is inversely proportional to coal thickness and proportional to rock-coal strength ratio; ⑤ The total energy, dissipative energy, elastic energy and surplus energy of RCR assemblage gradually decrease with the increase of coal thickness and gradually increase with the increase of rock-coal strength ratio, and the supercritical CO2 effect will cause the elastic energy ratio of RCR assemblage specimens to decrease, the dissipative energy ratio to increase and the surplus energy ratio to decreases. Combining the above research results shows that the thicker the coal seam is, the more likely it is to be destabilized, and the higher the strength of the top and bottom rock layer is, the less likely it is to be destabilized, and the dynamic strength of the seam destabilization is inversely proportional to the coal thickness and positively proportional to the rock-to-coal strength ratio. Therefore, in a certain area of stratum that meets the premise of CO2 injection and storage, the area of stratum with higher top and bottom rock strength and thinner coal seam thickness should be selected to store CO2 with higher safety. The research results can provide some theoretical reference for the safety of geological storage of CO2 injected into deep unmineable coal seams.

The relationship between groundwater replenishment, runoff and discharge to the coal seam affects not only the degree of coalbed methane (CBM) enrichment, but also the gas production characteristics of CBM wells. In order to identify the influence of hydrogeological conditions on CBM enrichment and gas production, the No. 15 coal seam in Shouyang block was used as the research object, and based on the ion test data of drainage water and underground water potential, the relationship between chemical characteristic parameters of drainage water, underground water potential and gas content was analyzed, combined with the hydrological control gas effect, and three types of reservoir control models were proposed. According to the water production, gas production curve shape and genetic mechanism of CBM wells under different reservoir control modes, six production control characteristics are divided, and corresponding development suggestions are put forward. The results show that: hydrochemical characteristic parameters and groundwater potential are significantly correlated with gas content. That is, the greater the mineralization and metamorphic coefficient, the smaller the sodium-chloride coefficient, carbonate equilibrium coefficient, and groundwater potential, the higher the gas content. Hydrodynamic force controls the escape and accumulation of coalbed methane by hydrodynamic dissipation, plugging and sealing. In the reservoir area controlled by hydrodynamic dissipation, low gas content is the main controlling factor of low production of CBM wells, and the development risk is high. In hydrodynamic plugging control areas, the water production of coalbed methane wells is generally large. Among them, strong hydrodynamic, low permeability prone to high water production and low production gas wells, not recommended for development; strong liquid supply capacity and low permeability are prone to medium water production and low production gas wells, the effect of reservoir reconstruction determines the feasibility of development. High production of water and gas is easy to occur in areas with high permeability, so the continuity of drainage should be pay attention. In hydrodynamic closed reservoir-controlling areas the water production of coalbed methane wells is generally small. Among them, low permeability reservoirs are prone to low water production and low gas production wells, so attention should be paid to the effectiveness of reservoir reconstruction; in the areas of high permeability reservoir, there are generally medium-high-yield gas wells. The continuity of drainage and production should be maintained as much as possible to reduce reservoir damage. The research results can provide theoretical guidance for the deployment of CBM wells.

In order to promote self-sufficiency of strategic resources and comprehensive utilization of seawater chemical resources, this paper conducted research on the extraction and utilization of seawater chemical resources from the perspective of ensuring the security of strategic resources. This paper analyzed the current situation and the key directions of the extraction and utilization of seawater chemical resources in China, and put forward suggestions from four aspects including strengthening top-level design, improving institutional guarantee system, building cooperation mechanisms and strengthening technological innovation capacity, aiming to better ensure the security of China's strategic resources and alleviate the problem of foreign resources dependence. At the same time, it provided reference for the development and management of seawater chemical resources in China.

A digital twin is a digital model that comprehensively and accurately depicts physical entities in a computer system. Such technology can improve the intelligent management level of waterway transportation. Based on an analysis of the key enabling technologies of a digital twin model for waterway transportation, including big data monitoring and analysis, digital twin model construction, real-time matching and interaction of virtual and real model information, data-driven control of virtual and real models, and dynamic visualization technologies, the research and application status of the intelligent manufacturing of ship systems, operation management of waterway transportation equipment, intelligent life cycle operation and maintenance, virtual scenario construction and virtual experiments based on the digital twin are analyzed in detail. On this basis, digital twin technology for waterway transportation is summarized and predicted, providing valuable references for the development and application of digital twin technology in the field of waterway transportation.

Extremophile strain Monascus pilosus YX-1125 was isolated from the baijiu-making environment. It was found that this strain could use sorghum as substrate and could tolerate multiple extreme environmental stress. Based on this, Monascus and Sorghum Fermentation Filtrate (MSFF) derived from this strain was developed, and its composition, safety, and bioactivity were studied. Research findings revealed that MSFF was abundant in various bioactive substances, including short-chain fatty acids such as propionic acid, butyric acid, and acetic acid, phenolic compounds (greater than 7.0 mg/mL) and 17 amino acids (greater than 7.5 mg/mL), and had strong antioxidant potentials (80% concentration of MSFF with DPPH scavenging 67.3%, copper chelation 59.71%, iron chelation 42.62%, hydroxyl scavenging 83.31%, superoxide scavenging 55.8%, and ferric ion reducing antioxidant power 1.24 mmoL eq FeSO4/mL). The results of in vitro experiments revealed that 1% (v/v) MSFF could inhibit inflammation and reduce its damage by reducing 81.4% cell apoptosis, removing 35.8% intracellular reactive oxygen species, inhibiting the release of proinflammatory cytokines (interleukins-6 and -8) up to 83.2% and down-regulating the expression of matrix metalloproteinases (MMP-1 and MMP-9) up to 42.5%. The safety test confirmed that MSFF had high cytocompatibility. In conclusion, MSFF was a safe and highly effective antioxidant and anti-inflammatory ingredient, which had great potential applications in the fields of health food and skincare.

This article collects the co-seismic response changes of the temperature and water level of Jiangsu fluid wells during the M7.4 earthquake in Maduo, Qinghai, summarizes their characteristics, analyzes the influencing factors in combination with the basic parameters of Jiangsu’s underground fluid wells and regional geological structures, and explores the changing mechanisms. The results show that the impact of the M7.4 earthquake in Maduo, Qinghai on underground fluids in Jiangsu was relatively significant, and the recording ability of the water level’s co-seismic response was better than that of the temperature. The temperature mainly showed step changes, while the water level mainly showed oscillations and step changes. The fluid wells that exhibited co-seismic response changes were mainly concentrated near the Tanlu fault zone and Maoshan fault zone. The regional and concentrated step changes in water level indicate that stress adjustment has occurred in the area, which has some indicative significance for the future occurrence of earthquakes. The co-seismic response mechanism of water temperature is more complicated. The movement mode and flow rate of water, wellbore conditions, and probe position may all affect its changes. More data is needed from various aspects to make a more accurate judgment.

The mechanical properties of creep coal bodies under the influence of dynamic pressure have important engineering significance for the stability and control of remained coal pillars in the re-mining area. The strain characteristics, elastic modulus and creep rate evolution characteristics of creep process of anthracite coal were studied by carrying out the graded loading creep and loading-unloading tests under different loading rates. The energy dissipation law of creep process was characterized based on the linear energy storage law of anthracite coal, and the “hardening-damage” mechanism of creep of anthracite coal was further explained. The results show that when the loading rate is less than 0.04 mm/s, the axial strain of the anthracite specimen shows obvious transient characteristics, but the radial strain shows obvious hysteresis and creep. With the increase of the loading rate, the axial hardening and radial expansion of the specimen in the loading stage are significantly enhanced, and the creep rate decay characteristics appear more obvious. The actual yield stress of the specimen meet the linear decreasing relationship with the loading rate, and its energy storage coefficient and creep limit elastic energy show the trend of increasing and then stabilizing with the increase of loading rate. The evolution of energy dissipation rate of each stress level shows the trend of “decreasing-stabilizing-increasing”, which is corresponded to the compression-density, elasticity and yielding damage stages of the specimen, respectively. The hardening-damage mechanism of anthracite specimens was analyzed from the perspective of energy dissipation. The hardening and damage effects act on the whole creep process, and the hardening and damage effects are comparable in the elastic stage, resulting in a stable energy dissipation rate of the specimen, and the damage effect dominates after the specimen enters the yield damage stage, resulting in a rapid increase in the energy dissipation rate. The specimen hardening and damage effects gradually become significant with the increase of loading rate. When the loading rate is less than 0.04 mm/s, the specimen hardening effect is stronger than the damage effect, resulting in a rapid increase in the ultimate elastic energy of the specimen. The yield stress reduction caused by the increase of loading rate will accelerate the evolution of the damage of the specimen, when the loading rate is greater than 0.04 mm/s, the damage effect of the specimen is significantly enhanced, and the mutual constraints of hardening and damage lead the ultimate elastic energy of the specimen to be stabilized.

To determine the dynamic matching of a mine ventilation system to onsite demands of automatic adjustment, we analyze the principle of air volume supply and demand matching and a linkage control method. Subsequently, we establish a mathematical model of main ventilator frequency adjustment, associate branch resistance adjustment, and joint adjustment with multi-feature fusion. We also propose a matching regulation model and a stability determination method for a ventilation network’s branch supply and demand. Based on the monitoring of harmful gases, intelligent emergency control software is developed by a mine ventilation supply and demand model. We realize the automatic calculation of the best working frequency of a ventilator when an unbalanced supply and ventilation demand is selected for frequency conversion adjustment. When selecting the associated branch wind resistance adjustment, we use a cellular automata model to calculate the optimal adjustment roadway. We obtain the adjusted wind resistance value using a winding network inversion calculation model. When a single adjustment method fails, a joint control scheme of fan frequency conversion and branch resistance adjustment is generated. A reliable adjustment of air volume supply and demand matching is realized through an advanced simulation analysis of the air network. A typical mine ventilation system is used to establish an experimental model for the automatic adjustment of the air demand of a branch of a winding network. The air demand adjustment and dilution experiment are carried out with the statistical law of onsite gas overrun as the guidance model of branch air demand control. The following results are obtained. The branch air volume changes according to the adjustment theory model under three adjustment methods. Further, the CO2 concentration change is evidently delayed in the air adjustment process. In the process of fan frequency conversion regulation, the air volume of each branch of the air network changes according to the ventilation network sensitivity, and the fluctuation of the air network is minimal. When a single associated branch resistance adjustment method is used to regulate the wind, the local wind network has great influence on air volume and thus fluctuates greatly. When the fan frequency and associated branch wind resistance are combined, the fluctuation of the branch air volume of the entire air network is the largest, and the system stability and security are the lowest. Therefore, the fan frequency and combined regulation methods of multiple associated branches are recommended to use in practical applications of mines. The experiment verified the practicability and feasibility of the deviation of mine ventilation supply and demand from intelligent control systems. It also provided theoretical and application guidance for mine ventilation linkage control.

[Introduction] As an important construction equipment in the development of offshore wind power, studying the bearing performance of the jack-up vessel for wind turbine installation in the in-situ state to ensure its operation safety is of great significance. [Method] In this paper, taking the jack-up installation vessel as the research object, the horizontal bearing performance of the jack-up installation vessel and the variation law of the surrounding earth pressure at four different penetration depths of spudcans in homogeneous sandy soil were studied by combining with the indoor model tests and finite element method. [Result] The results show that with the increasing of the penetration depth, the horizontal bearing capacity of the jack-up installation vessel is on an approximate linear growth trend. The penetration depth of 10 cm led to an increase of the horizontal bearing capacity by 38.02% compared with 4 cm penetration depth, and the corresponding horizontal displacement also show an increasing trend. Under the action of horizontal loads, the bearing mode of spudcans is characterized by compression of spudcans on the loading side and tension of spudcans on the non-loading-side. The pressure change law of the soil on the surface of spudcans is the same. At the penetration depth of 10 cm, the maximum variation in soil pressure at the bottom of spudcans on the loading side is 38.37 kPa, which increased by 126.2% compared to the penetration depth of 4 cm. In addition, significant variations in soil pressure are observed on the lower surface of the loading-side spudcans and the upper surface of the non-loading-side spudcans. [Conclusion] Under the action of horizontal load, the force mode of the jack-up installation vessel is the tension-compression mode, and increasing the penetration depth of spudcans in sandy soil can significantly enhance the horizontal bearing capacity. Therefore, in order to ensure the safety and operational capability of the wind turbine installation vessel, it is necessary to ensure sufficient penetration depth of spudcans.

Cirrus clouds play a significant role in Earth's energy balance and in the hydrological cycle of the atmosphere.In this study， we focus on the period of several years， 2007 to 2010， and the area， the Qinghai-Xizang Plateau， to analyze the generation mechanism and the distribution characteristics of cirrus clouds by using the data of “Cloud Satellite” （CLOUDSAT） and “Cloud-Aerosol Lidar and Infrared Pathfinder Satellite” （CALIPSO）.Counting the number of the occurrence of cirrus clouds in different height， including high-level cirrus clouds and low-level cirrus clouds， the results show that the total occurrence frequency of high-level cirrus clouds is much higher than that of low-level cirrus clouds during the selected period and area.High-level cirrus clouds usually occur in the southern part of the plateau， and low-level cirrus clouds have much occurrence frequency both at the edge of the plateau and in the western part of the plateau.Besides， when calculating the loss of the gravitational wave， the result also shows an important relationship between the gravitational wave and the occurrence frequency of low-level cirrus clouds， that they are positively correlated with each other.To be specific， the larger the gravitational wave loss， the more cirrus clouds occur.The reason why this phenomenon occurs is that the formation of cirrus clouds in the plateau area is closely related to the temperature disturbance which is caused by the gravitational wave.By investigating in the selected area， there is the phenomenon that the deep convection mostly occurs in the southeast of the Qinghai-Xizang Plateau and the following conclusions can be drawn： When the outward longwave radiation （OLR） is lower than 140 W·m-2， that is， the deep convection activity is the strongest， the daily occurrences frequency of high-level cirrus clouds grows explosively， being much higher than the northern and western regions of the plateau.In addition， on southern edge of the Qinghai-Xizang Plateau， cirrus clouds not only are influenced by the deep convection， but also are closely related the water vapor content and vertical upward wind speed， which shows a decreasing trend from south to north.All the phenomenon on southern edge of the Qinghai-Xizang Plateau is directly related to the elevation of terrain in the plateau.

To resolve problems involving undersea vehicle-manipulator systems(UVMSs) with coupling terms, model uncertainties, and disturbances, an adaptive-disturbance-observer-based backstepping control method is proposed. Ocean multi-source disturbances are described by a linear exosystem and an adaptive disturbance observer is presented to estimate the disturbances. To address saturation of the actuators, an auxiliary dynamic system is given. A backstepping control method is then presented to ensure that the closed-loop tracking system is bounded by the Lyapunov theory. Finally, simulations are conducted on a kind of UVMS with two joints, and the simulation results demonstrate that the proposed method exhibits better performance in terms of trajectory tracking and antidisturbance than the traditional proportional-integral-derivative control method.

In view of the problems existing in the current public charity industry, such as opaque, untraceable and easy to tamper with donation information, a public charity donation traceability system model based on consortium blockchain was constructed.In the process of consensus, an improved PBFT consensus algorithm——DG-PBFT algorithm was applied, which improved the original random election of the master node to the points system election, and optimally transformd the original three-stage consensus into two-stage consensus.The system was developed on Hyperledger Fabric platform, and the Go language was used for chain code development.Four organizations corresponding to donors, recipients, charities and regulatory departments were configured.Smart contracts were designed according to functional requirements, which not only realized the traceability of donation information, but also could appeal and supervise through the traceability system.The experiment results showed that the traceability system could not only ensure the degree of decentralization, but also enhance the reliability of data, ensure the security of data, reduce the communication cost and improve the efficiency of traceability.

In view of the difficult situation of fire prevention, control, disaster resistance and relief in complex ventilation networks, the laws of air flow disturbance, heat transfer and smoke flow diffusion in air flow field, temperature field and smoke flow concentration field are analyzed. According to the evolution law of smoke flow at different fire source locations, an emergency linkage regulation scheme of fire air and smoke flow that can simultaneously meet the requirements of smoke exhaust air volume and stope air volume is proposed. Taking Zhuanlongwan Coal Mine as an application case, the fire smoke emergency linkage control system of Zhuanlongwan Coal Mine was established. In order to analyze the effect of air control and smoke exhaust, combined with the actual tunnel and ventilation parameters, a three-dimensional visualization model of its complex ventilation network was built based on VENTSIM software. The VentFire module is used to simulate the wind and smoke spreading effect of the fire scene in different fire source locations. The smoke exhaust effect and air volume distribution before and after the emergency control scheme is adopted are analyzed. The results show that when a fire occurs in different locations, the emergency smoke exhaust scheme should be started in time. On the basis of meeting the smoke exhaust air volume, the air volume of other key locations can still ensure more than 90% of the normal ventilation period, which can meet the disaster control and relief needs during the disaster of Zhuanlongwan Coal Mine.

The deformation and failure characteristics of coal around gas drainage boreholes in deep soft and low permeability coal seams affect coal seam gas pre-drainage. Based on the condition of non-uniform stress field, the mechanical model of borehole disturbed coal mass was developed, the analytical solutions of stress, strain and displacement in the damaged zone, plastic zone and elastic zone of borehole disturbed coal mass were deduced, the influence law of factors such as lateral pressure coefficient, load condition, cohesion and hole expanding behavior on the “three zone” distribution of disturbed coal mass were analyzed, and the reliability of the theoretical model was verified through engineering examples. The results show that under the condition of non-uniform stress field, the plastic zone and damaged zone of disturbed coal mass are elliptical distribution. With the increase of lateral pressure coefficient, the length of the upper and lower wings of the plastic zone and damaged zone of disturbed coal mass becomes larger and larger, and the radius of the plastic zone and damaged zone in the direction of smaller stress is greater than the radius of the two zones in the direction of large stress. The radius of plastic zone and damaged zone of coal mass increases with the increase of vertical load, and decreases with the increase of initial cohesion and residual cohesion. The influence of vertical load on its shape can be ignored. When the borehole diameter is expanded from 0.1 m to 0.5 m, the coal mass 0−1.0 m away from the borehole center produces a strong disturbance, the coal mass 1.0−4.6 m produces a weak disturbance, and the coal mass after 4.6 m has almost no influence. Through the field example of No.16032 bottom pumping roadway hydraulic reaming in the Guhanshan coal mine, it is observed that the disturbed coal mass in the reaming section has a high degree of damage. Based on the coal output, the reaming diameter is deduced to be 1.5 m, and then the deformation and damage characteristics of drilling reaming coal mass are obtained through theoretical calculation and numerical simulation respectively. The two are in good agreement, so as to verify the reliability of the theoretical model.

The effects of 1.5 and 2.5 h of ultrasonic treatment and 16, 32 and 48 h of enzymatic hydrolysis with galactosidase on the rheological properties of Xyloglucan (XG) from tamarind were studied. The viscosity and module of untreated and treated XG were studied under static and dynamic shear using a rotational rheometer. The molecular weight distribution and average particle size were analyzed using gel chromatography with multi-angle laser light scattering and dynamic laser light scattering instruments. In addition, the microstructure of XG samples were observed via scanning electron microscope. Results of the temperature sweep showed that the viscosity of XG treated by ultrasound and enzymatic hydrolysis significantly decreased at 5 ℃, but the difference of samples treated for different durations was small. In the range of 5 to 60 ℃, the elastic and viscous modulus of XG were close to 7 Pa. The viscosity of ultrasonic treated XG decreased with the increasing of temperature, and the rheological properties of ultrasonic samples was viscous-dominant. The elastic properties of XG treated with 48 h enzymatic hydrolysis were higher than those treated with 16 and 32 h enzymatic hydrolysis. The results of molecular weight analysis showed that the average molecular weight of ultrasonic-treated 1.5 and 2.5 h XG decreased from 885 kDa to 780 and 520 kDa respectively. The enzymatic hydrolysis of XG was composed of a low molecular weight (101~478 kDa) ratio and a high molecular weight (4591~12173 kDa) ratio, of which the low molecular weight component accounted for more than 80%. The results of dynamic light scattering showed that the average particle size of XG increased after galactosidase hydrolysis, while ultrasonic treatment had little effect on the particle size of XG. This study would provide experience on the physical and biological modification on xyloglucan to obtain carbohydrate colloids with various rheological properties, which is beneficial for its further application in food industry.

Honey is a natural sweet substance made from a mixture of nectar collected by worker bees and their own secretions, which has good antibacterial activity and contains a variety of natural antibacterial active substances. In recent years, a large number of studies have been reported on the progress of antimicrobial active substances in honey, including methylglyoxal, hydrogen peroxide, polyphenols, antimicrobial peptides and Major royal jelly proteins. Numerous studies have shown that hydrogen peroxide is one of the most important antibacterial substances in honey. This paper highlights the important roles by each antimicrobial effective active substance for the anti-bacterial by honey. It also further summarizes the process of glucose oxidase catalyzing the production of hydrogen peroxide from glucose. The process of glucose oxidase catalyzing the production of hydrogen peroxide from glucose is summarized using hydrogen peroxide in honey as an example. Other pathways for the production and degradation of hydrogen peroxide and the physicochemical factors affecting the production of hydrogen peroxide are also reviewed. Rational regulation of hydrogen peroxide production in honey plays an important role in its antibacterial and even other biological activities. This review would also provide a reference for the safe clinical use of honey and the development of functional foods.

The present project objective was to evaluate physicochemical and nutritional changes of mango cv. Tainung No.1 that included firmness, color, total soluble solids (TSS), titratable acidity (TA), carotenoid, vitamin C (VC), protein, total sugar and aroma component at 10 postharvest ripening-stages under the ripeing condition (0.1% w/w ethephon, 30 °C, 40%～50% humidity). Results indicated a decrease in firmness from 19.76 to 0.99 N, while TA decreased from 1.37% to 0.27% and TSS increased from 12.92% to 23.64%. When the ripening time increased from 0 to 60 h, the yellow index increased significantly, and more than 85% of fruit skins turned yellow. The content of carotenoid increased to 4.90 µg/g (maximum), while VC decreased from 326.66 mg/100 g to 180.00 mg/100 g, and total sugar content increased significantly. When ripening time extended to 108 h, the content carotenoid increased to 10.93 µg/g, and the changes of the VC, soluble protein and total sugar were not significant. The aroma compounds of mango was mainly terpenes, among which the content of terpinolene was the highest, and its content increased rapidly within 60 h of ripening. Exogenous ethephon accelerated the synthesis rate of iso-terpinene in fruits. After 60 h of ripening, the color and aroma of mango reached maturity.

BackgroundThe use of heating and ventilation air conditioning (HVAC) in public places is conducive to improving indoor air quality and increasing the users comfort level. However, HVAC may also become potential carriers of indoor airborne microbial contamination.ObjectiveTo understand the characteristics of microbial pollution and distribution of related pathogenic microorganisms in HVAC of star-rated hotels, and to provide a basis for effective control of such pollution.MethodsAccording to the requirements of the Hygienic specification of central air conditioning ventilation system in public buildings (WS 394-2012), two sets of HVAC in two star-rated hotels (A and B, inaugurated in 2002 and 1998, respectively) in the central area of Shanghai were randomly selected on September 9, 2020 for the hygienic evaluation of microorganisms in the air supply and respirable particulate matter (PM10) in the air supply, dust accumulation and microorganisms on the inner surface of the ducts, as well as Legionella pneumophila in cooling water and condensate water. At the same time, 3 samples from the inner surface of ducts, 1 sample from the surface of the filter, 1 sample from the condensate, and 1 sample from the cooling water were collected from each set of HVAC, a total of 12 sample from 2 sets of HVAC, for Illumina HiSeq metagenomic sequencing，and the samples are divided into 3 groups according to their types: duct group, filter group, and water sample group. The α-diversity indices (Shannon index, Simpson index, Chao1 index, ACE index, and goods_coverage index) were calculated to reflect the microbial community composition; and the β-diversity of the three groups were studied by principal component analysis to determine the similarity of the microbial communities.ResultsThe maximum total number of bacteria and fungi in the air supply of the HVAC were 1158 CFU·m−3 and 344 CFU·m−3 for Hotel A respectively; and 2000 CFU·m−3 and 532 CFU·m−3 for Botel B respectively. β-hemolytic streptococci were negative in all samples; the respirable particulate matter, microorganisms and dust accumulation on the inner surface of air ducts, Legionella pneumophila IN cooling water and condensate samples all met the standards. The results of Illumina HiSeq sequencing showed that a total of 17322 microorganisms were reported in the 12 samples, with bacterial microbiota accounting for 97.31% of the classified genes and the remaining 2.69% were from fungi, viruses, and parasites. At the species level, Staphylococcus epidermidis, Pseudomonas, Alternaria, and Malassezia were the dominant microbial taxa measured in this survey. The results of α-diversity analysis showed that the values of Shannon index, Simpson index, and Chao1 index for the three groups of samples were duct > filter > water sample. The goods coverage indices of all sample groups s were close to 1. The principal component analysis showed that the contributions of two principal components were 19.27% and 14.25%, respectively, in which the samples of the filter and duct groups were better clustered into one category.ConclusionThe overall hygiene conditions of the two hotels are good, except for the serious microbial contamination in the air supply of HVAC. Metagenomic sequencing reveals complex microbial communities of HVAC, including bacteria, fungi, viruses, and parasites. The species composition vary by sample groups, particularly the species compositions of the samples from filters and ducts are close and dominated by pathogenic microorganisms of human origin, suggesting that the potential biosafety hazards of HVAC should not be ignored.

BackgroundPM2.5 pollution has become a widely concerned environmental health problem. Polycyclic aromatic hydrocarbons(PAHs) are the main harmful components of PM2.5, and their sources and carcinogenic risk deserve attention.ObjectiveTo analyze the source apportionment of PAHs in ambient PM2.5 in Fuzhou, and to evaluate the potential carcinogenic risk through inhalation due to exposure to PAHs.MethodsIn this study, two sampling sites were set up in Cangshan (industrial area) and Taijiang (commercial and residential area) districts in Fuzhou City. PM2.5 was collected from 10th to 16th of each month from 2017 to 2020 by membrane filtration method. The concentrations of ambient PM2.5 were measured by weighing, and the concentrations of 16 PAHs, including naphthalene(NAP), acenaphthylene(ACY), acenaphthene(ACE), fluorene(FLU), phenanthrene(PHE), anthracene(ANT), fluoranthene(FLT), pyrene(PYR), benzo[a]anthracene(BaA), chrysene(CHR), benzo[b]fluoranthene(BbF), benzo[k]fluoranthene(BkF), benzo[a]pyrene(BaP), indeno[1,2,3-cd]pyrene(IcdP), dibenzo[a,h]anthracene(DahA), and benzo[g,h,i]perylene(BghiP), were determined by ultra-high performance liquid chromatography coupled with diode array detector and fluorescence detector. The concentrations of PM2.5 and PAHs were compared in the two districts and the concentrations of PAHs were also compared in different seasons. The diagnostic ratio [FLT/(FLT+PYR), IcdP/(IcdP+BghiP), BaA/(BaA+CHR), and BaP/BghiP] method and positive matrix factorization (PMF) analysis were used to determine the sources of PAHs in PM2.5 in Fuzhou. The excess carcinogenic risk (ECR) model was used to assess the potential health risk of inhalation exposure to PAHs.ResultsDuring 2017–2020, the M (P25, P75) concentration of ambient PM2.5 in Cangshan and Taijiang districts of Fuzhou were 35.0 (25.0, 47.5) and 34.0 (25.5, 46.0) μg·m−3 respectively, and the percentages of PM2.5 exceeding the national standard in Cangshan and Taijiang were 2.68% and 4.17%, respectively, without significant differences (P＞0.05). The M (P25, P75) concentrations of ΣPAHs in Cangshan was 5.03 (3.07, 7.67) ng·m−3, higher than that in Taijiang, 3.20 (2.05, 5.59) ng·m−3 (P＜0.05). The M (P25, P75) concentrations of PAHs monomers except ACY, FLU, and ACE in Cangshan were higher than those in Taijiang (P＜0.05). The concentrations of ΣPAHs in PM2.5 in four seasons in Cangshan were higher than those in Taijiang (P＜0.05). In both districts, the concentration of ΣPAHs in winter was higher than those in spring, summer, and autumn (P＜0.05). According to the diagnostic ratio method, the median ratios of FLT/(FLT+PYR) in the two districts ranged from 0.4 to 0.5, and those of IcdP/(IcdP+BghiP), BaA/(BaA+CHR), and BaP/BghiP were from 0.2 to 0.5, from 0.2 to 0.35, and less than 0.6, respectively. The results of PMF analysis showed the proportions of four factors in Cangshan were 37.9%, 13.2%, 24.0%, and 24.9%, respectively. The major load contributors to factor 1 included FLT, PHE, and PYR; to factor 2, FLU, ACY, and ACE; to factor 3, DahA; to factor 4, BghiP, IcdP, and BaP. The proportions of four factors in Taijiang were 23.6%, 19.3%, 22.0%, and 35.1%, respectively. The main load contributor to factor 1 was DahA; to factor 2, BghiP; to factor 3, FLT, PHE, and PYR; to factor 4, IcdP, BaP, BbF, BkF, CHR, and BaA. The benzo[a]pyrene equivalences (BEQ) in Cangshan and Taijiang districts were 1.87 ng·m−3 and 1.61 ng·m−3, respectively. The excess carcinogenic risks of PAHs through inhalation exposure was 3.83×10−6 and 3.30×10−6, respectively.ConclusionThe complex sources of PAHs in ambient PM2.5 include dust, vehicle emissions, industrial emissions in Fuzhou, and are different in selected two districts. The level of PAHs in ambient PM2.5 may pose a potential carcinogenic risk to local population.

Objective To explore the influencing factors and characteristics of blood donation-related vasovagal reactions in whole blood donation in Hefei city, and to put forward specific prevention measures. Methods Whole blood donors with vasovagal reactions related to blood donation in Hefei area from January 2021 to December 2021 were selected as the study subjects, and the related factors such as gender, age, blood donation month, initial or multiple blood donation, blood donation volume, blood donation location, and organization type of blood donation were retrospectively analyzed. Results The incidence of blood donation-related vasovagal reactions was 10.46‰ in the whole blood donation in Hefei in 2021, among which 71.89% occurred during blood collection. There were statistically significant differences in blood donation-related vasovagal reactions by blood donation age, blood donation history, blood collection month, organization type of blood donation and blood donation volume(P0.05). After balancing the age factors, there was no statistically significant difference in the incidence of DRVR between donors aged 18~22 and 23~29 years by gender(P>0.05), while there were significant differences in blood donors aged 30~39, 40~49, and 50~60 years by gender(P

In order to promote the development of the carbon sink fisheries and the construction of national parks in Changdao, this paper calculated the carbon sink data of marine bivalves and seaweeds in Changdao for the first time, comprehensively evaluated the carbon sink capacity of mariculture in Changdao and its influencing factors, and put forward countermeasures and suggestions. The results showed that mariculture in Changdao had a certain carbon sink capacity. The average carbon sink of shellfish cultured in Changdao from 2016 to 2020 was 29 400 tons, and the carbon sink of shellfish, especially scallop, was significantly higher than that of algae; the structure and yield of mariculture were the main factors affecting the carbon sink capacity of Changdao mariculture, and the yield of mariculture was also affected by the scale, environment and technology. In the future, the development of carbon sink fisheries in Changdao should further optimize mariculture structure, establish mariculture carbon sink accounting system, and formulate and implement related policies.

In this study, gas chromatography-ion mobility spectrometry (GC-IMS) was used to analyze the volatile components of passion fruit of different maturity, and a method was established to quickly distinguish the flavor differences of fruits of different maturity. A total of 33 kinds of volatile organic compounds were identified by GC-IMS, mainly including five categories of alcohols, esters, aldehydes, ketones and terpenes. There were significant differences in volatile organic compounds between ripe fruits (60 days after flowering) and less ripe fruits (50 days after flowering), and the contents of most volatile compounds in ripe fruits were higher. Including ethyl DL-2-hydroxy-4-methylvalerate, 2-pentanone, butyl acetate, 2-heptanone, α-pinene, (E, E)-2,4-heptadienal, benzaldehyde, limonene, β-ocimene, 2-butanone, methyl butyrate, ethyl butyrate and ethyl acetate, etc; while a few volatile substances were found in higher levels in less ripe fruits, including isoamyl acetate and isobutyl acetate, etc. GC-IMS can quickly detect and discriminate the flavor characteristics and differences of passion fruit at different maturity levels. The results of this study can provide scientific basis and reference for the harvesting and quality control of passion fruit.

This paper is aimed at investigating the evolution of fluidity and rheological properties of fresh CFB with different foaming agent dosage and particle size distributions (PSD) of filling aggregate, and revealing the mechanism of fluidity evolution based on water film thickness (WFT) theory. The results show that the flowability (spread diameter) of fresh CFB increases with increasing particle size of filling aggregate (D(4, 3)∈[192 μm, 398 μm]) and decreases with increasing foaming agent dosage. The former is related to the particle gap and specific surface area, while the latter to the number and distribution of bubbles in the slurry. PFC3D was used to simulate the accumulation model of bubbles and solid particles. At the calibrated simulation error coefficient of 1.1, the relationship between water film thickness of fresh CFB and spread diameter of slurry was analysed. The bubbles in slurry change the water film thickness by changing the overall packing compactness and specific surface area of fresh CFB, and then affect its fluidity.

An anticlinal structure with an axis plane along Yanhe river and a strike of about 330° is developed in the bedrock strata within the main urban area of AnSai County. In the bedrock strata, there are generally two groups of tensile joints parallel to the fold axis plane (320°-340°) and vertical (40°-60°), and two groups of conjugate shear joints diagonally intersecting the fold axis. The first group of conjugate shear joint planes struck direction near N-S (0°-10°) and near E-W (80°-90°), while the second group of conjugate shear joint planes strikes direction 100°-120° and 200°-210°. The multiple groups of joints with different strike directions developed in the bedrock have a strong control effect on the development of the collapse structure control plane with the same strike distribution in the study area. In the first group of conjugate shear joints, the near E-W (80°-90°) distributed joint planes control strongly the most developed collapse structure control planes in the study area, and it has the highest correlation with the development of rock collapse in the study area. Secondly, two groups of tensile joint planes control two groups of highly developed rock collapse structural control planes with the same strike, and the second group of conjugate shear joint planes controls two groups of relatively less developed rock collapse structural control planes with the same strike.

The split anti-backlash worm pair eliminates the worm backlash by rotating and adjusting the distance between the two worms. In view of its anti-backlash method and the structural characteristics of the existence of thinner worm teeth， the factors affecting the transmission accuracy of the split anti-backlash worm pair are studied， a 3D model and motion analysis model of split anti-backlash worm pairs are established and the influencing law of worm pair use error and worm pair structure error on the transmission accuracy of worm pairs is studied. The result shows that the use error of the worm pair has a greater impact on the transmission accuracy of the worm pair than the structural error of the worm pair does， the wear in the worm gear teeth has the greatest impact on the transmission accuracy in the use error and the radial error in the structural error has the greatest influence on the transmission accuracy.

High-power and fast-discharging lithium-ion battery, which can be used in smart power grids, rail transits, electromagnetic launch systems, aerospace systems, and so on, is one of the key research directions in the field of lithium-ion batteries and has attracted increasing attention in recent years. To obtain lithium-ion batteries with a high power density, the cathode materials should possess high voltage and high electronic/ionic conductivity, which can be realized by selecting high-voltage materials and modifying them to improve the voltage and reduce the battery’s internal resistance. Currently, the cathode materials of high-power lithium-ion batteries mainly include high-voltage LiCoO2, LiNi0.5Mn1.5O4, and Li(NiCoMn)O2 materials. Meanwhile, the anode materials include carbon- and Ti-based materials and metal oxides. This paper reviews the research on the modification of these materials, such as element doping and surface coating, which have gained considerable attention nowadays, as well as some new types of anode materials that exhibit excellent electrochemical properties. In terms of the negative electrode, the prelithiation process is one of the effective means to improve the power performance of a lithium-ion battery. This process’s significance is to compensate the consumption of Li+ and reduce the potential of the negative electrode to the working range for improving the platform voltage of the battery and improving the power density and energy density. This paper summarizes several commonly used prelithiation methods of the lithium-ion battery. Finally, the lithium salts, solvents, and additives for the electrolytes of lithium-ion batteries are introduced on the basis of their classification, properties, and performances. Several new types of lithium salts and additives are mentioned herein, such as lithium bis(fluorosulfonyl)imide, lithium bis(oxalate)borate, and tetramethylene sulfone. Furthermore, this paper summarizes several common power density test methods of lithium-ion batteries and prospects the research of high-power lithium-ion batteries. As a matter of fact, the power performance of lithium-ion batteries is gaining increasing attention and has truly achieved considerable improvement in recent years.

Objective To investigate the effect of two different oral calcium supplementation methods(method 1: bone health basic supplements in the interval plus routine calcium supplement; method 2: only routine calcium supplement on the day of donation)on platelet donors, to improve some biochemical indexes of the body caused by citrate anticoagulant. Methods A total of 252 long-term regular platelet donors in our station from January 2019 to December 2020 were selected and randomly divided into two groups: experimental group (n=126) were given 10% calcium gluconate oral solution 20 mL before platelet collection, orally. Oral caltrate D3 (containing 600 mg calcium carbonate and 125 international units of vitamin D3) was administered in the interval (20±2 days), 1 tablet per day. Oral alfacalcidol soft capsule (containing alfacalcidol 0.25 μg), 1 tablet per day; control group (n=126) were given routine administration of 10% calcium gluconate oral solution 20 mL before platelet collection. Serum PTH and serum concentrations of calcium, magnesium, phosphorus and 25 hydroxyvitamin D of the two groups were detected at 0 min after injection and 0 min after the end of the last circulation, respectively. Meanwhile, the occurrence of blood donation reactions was observed in the two groups. Results In the experimental group and control group, serum PTH concentration both increased significantly after donation, while serum calcium, inorganic phosphorus, magnesium and 25 hydroxyvitamin D decreased significantly(P0.05), and so was in the control group after blood collection. Conclusion Method 1 can further slow down the increase of serum PTH and the decrease of serum calcium, and can effectively reduce the citrate response of blood donors compared with method 2, which is of great significance to prevent osteoporosis in long-term regular blood donors.