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In order to investigate the influence of gas mixture (O2/N2 and O2/N2/CO2) on the spontaneous combustion characteristics of coal, synchronous thermal analyzers, temperature programmed gas chromatography/infrared spectrometers were used to study the characteristic temperature, thermal effect/indicator gas, and functional group changes of coal under gas mixture. The results show that under O2/N2 atmosphere, with the increase of N2 volume fraction, the characteristic temperature point lags behind, TG, DTG, DSC all shift towards high temperature, heat release decreases, activation energy during combustion stage increases, final oxygen consumption and CO volume fraction of coal decrease, hydroxyl groups in coal increase, and the content of aliphatic hydrocarbons, oxygen-containing functional groups, and aromatic hydrocarbons shows a decreasing trend; under O2/N2/CO2 atmosphere, as CO2 increases, the characteristic temperature point shifts backward, the heat release decreases, the activation energy during the combustion stage decreases, the oxygen consumption and CO volume fraction both decrease, hydroxyl and fatty hydrocarbons increase, and the content of oxygen-containing functional groups decreases; when the volume fraction of O2 is the same, the peak weight loss rate, oxygen consumption, and CO volume fraction in the O2/N2/CO2 mixture are all lower than those in O2/N2; −OH is easily oxidized and undergoes dehydration reaction. Coal releases less heat in the initial stage of the reaction, but rapidly increases in the later stage. CO is mainly generated by −C=O.

Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The organic isooctyltriethoxysilane (TS) and inorganic nanosilicon dioxide (nano-SiO2) were combined to prepare monolithic superhydrophobic hydraulic concrete by "binary synergistic" biomimetic method, and the effects of TS dosage and curing conditions on the mechanical properties and hydrophobicity properties of concrete were investigated. The microscopic morphology, phase composition and hydrophobic modification mechanism of materials were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and fourier transform infrared spectrometer (FT-IR). The results show that the curing conditions have a large influence on the hydrophobicity of concrete. Under natural curing conditions, when TS dosage reaches 3% (mass fraction), the concrete all exhibits superhydrophobicity, with a maximum contact angle of 155.6°. The incorporation of nanoparticles promotes cement hydration and enhances compressive strength of specimens. The modified hydraulic concrete has good hydrophobicity, and the water absorption rate decreases by 68.8% in 288 h immersion. [ABSTRACT FROM AUTHOR]

In order to explore the influence law of igneous rock erosion on coal spontaneous combustion characteristics and structure, taking primary coal and igneous rock eroded coal in the same coal face of Shanxi Mine and Liaoning Mine as the samples, the oxidation characteristics, the limit parameters of the spontaneous combustion, the content of the active functional group and pore structure characteristics of coal were analyzed from macro and micro perspectives by temperature programmed test, FT-IR experiment, low temperature nitrogen adsorption experiment and mercury injection experiment respectively. The results of temperature programmed test showed that igneous rock erosion increased the spontaneous combustion risk of coal, igneous rock erosion could enhance the gas circulation inside the coal body, which is conducive to the oxidation reaction between oxygen and active groups inside the coal body, and the coal body of the igneous erosion had higher oxidizing activity. In addition, igneous rock erosion altered the occurrence conditions of coal seams, increased the difficulty of coal seams mining and the intensity of wind leakage in the mining airspace, prolonged the oxidation time of the residual coal in the “oxidized heating zone” in goaf, thus increasing the risk of spontaneous combustion of coal from the level of external influencing factors. The erosion of igneous rock changes the structure of coal itself and the external environmental factors of coal spontaneous combustion, which intensifies the spontaneous combustion risk of the eroded coal seam.

Copyright of Bulletin of Soil & Water Conservation is the property of Bulletin of Soil & Water Conservation Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to explore the influence of magmatic intrusion on coal spontaneous combustion characteristics in deep mines, the micro functional groups and spontaneous combustion process changes of magmatic intrusion coal and raw coal were compared and studied by infrared spectrum experiment and thermogravimetric experiment, and the kinetic parameters of the two at different oxidation stages were calculated. The results show that the aromatic hydrocarbon compounds, associated hydrogen bonds and - OH (free) in magmatic intrusive coal show a decreasing trend, while the contents of - OH, - C-O-C -, - C = O and - COOH groups in aliphatic hydrocarbon compounds and oxygen-containing functional groups increase in varying degrees. The spontaneous combustion process of raw coal and magmatic intrusive coal can be divided into three stages: water evaporation, oxygen absorption and weight gain and decomposition combustion. Compared with raw coal, the mass peak temperature and ignition point temperature of magmatic intrusive coal decrease, while the dry cracking temperature, weight loss rate peak temperature and burnout temperature increase. In addition, the activation energy of magmatic intrusive coal in the stage of water evaporation and decomposition combustion is less than that of raw coal, indicating that the magmatic intrusive coal is more likely to react with oxygen in this stage.

Fourier transform infrared spectroscopy (FTIR), as a non-destructive method, is widely used for the identification of compounds and the characterization of molecular structures. In order to characterize the changes in the chemical structure of charcoal under different combustion temperatures, and thus to provide a theoretical basis for the formation of fusinite in coal, plant samples (charcoal) from modern wildfires with different degrees of combustion were selected to quantify their chemical structures using FTIR. The results shown that the sample reflectance was positively proportional to the combustion temperature. The sample No. 1 with maximum combustion temperature had the highest degree of combustion, which was measured to reach 518 ℃. The aromatic structure was dominated by tri-substituted benzene rings in all samples except the highest combustion sample No. 1, but dehydrocondensation occurred with increasing combustion temperature, resulting in a reduction of tri-substituted content of benzene rings to 20.5%. The tetra-substituted content was elevated due to dehydroaromatization of the naphthenic structure, while the change in the penta-substituted content was related to the cyclization of aliphatic chain and the decarboxylation of benzene ring. With the increase of combustion temperature, the CC content gradually increased due to the formation of aromatic hydrocarbons or the shedding of molecular side chains after dehydrogenation of cycloalkanes, reached 32% in the sample No. 1. The content of C－O first decreased and then increased. In the sample No. 1, the content of alkyl ether and aryl ether was the lowest, and the content of phenolic hydroxyl group was the highest, which may be the generation of phenolic substances by thermal breakage of ether bond under high temperature combustion. The CO content increased and then decreased to as low as 5.6% in the sample No. 1, which was due to the poor stability of the bond. Due to the influence of combustion temperature, the content of fatty substances varied greatly, with an overall gradual increase in methylene content, a decrease in methyl group, and an increase in branching degree. There were five types of hydrogen bonds in the samples, with ether-oxygen hydrogen bonds predominating in samples affected by low temperature (>55%). Cyclic hydrogen bonds and hydroxyl-N hydrogen bonds appeared in sample No. 1, while the content of ether-oxygen hydrogen bonds decreased significantly to 13.2%, which was attributed to the reduction of oxygen-containing functional groups caused by the increasing temperature. Comparison of reflectance and FTIR characteristics of fusinite in coal revealed that the characteristics of fusinite (semifusinite) in coal were very similar to those of charcoal, which might be produced mainly by wildfires. These changes indicated the effect of combustion temperature on the chemical structure in charcoal, reflecting the process of organic molecular structure changed with temperature in charcoal, and providing a theoretical basis for the evolution of organic matter and the formation of fusinite in coal.

In order to explore the mechanism of inhibitor on coal spontaneous combustion, the oxygen-containing groups aldehyde （-CHO） and methoxy（-OCH3） in coal molecular side chain were selected as the subjects of the study. The geometric configuration, electrostatic potential, reaction tendency, frontier orbitals, natural bond orbitals and charge transfer of the oxygen-containing groups（-CHO and -OCH3） and their complexes with Na+, Ba2+ and Ca2+ were deeply studied by using Gaussian 16W simulation software. The results show that Na+, Ba2+ and Ca2+ tend to cooperate with the oxygen-containing groups to form complexes, which weakens the electrophilic reaction ability and disables the nucleophilic reaction ability of -CHO and -OCH3 oxygen-containing groups, thus reducing the chemical activity of oxygen-containing groups. Metal ions increase the energy level difference（ELOMO-EHOMO） and the absolute value of the highest occupied molecular orbital（HOMO） energy of oxygen-containing groups, and thereby increases the stability of oxygen-containing group. The results of natural bond orbital theory analysis（NBO） shows that -CHO and -OCH3 oxygen-containing groups can coordinate steadily with Na+, Ca2+ and Ba2+, and the electrons of O in the two the groups transfer to Na+, Ca2+ and Ba2+ to form coordinate bonds. The combination of oxygen-containing groups with metal ions reduces the chance of contact between oxygen-containing groups and oxygen, which inhibits coal spontaneous combustion.

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

From November 2021 to September 2022, we conducted four field surveys on macroinvertebrates and water environmental factors in Xinyang section of the Huaihe River main stream. We analyzed the structure and spatio-temporal distribution characteristics of the functional feeding groups of macroinvertebrates, and evaluated river water quality. A total of 73 macroinvertebrate species were collected in the basin, belonging to 42 families, 7 classes, and 3 phyla. The dominant species of macroinvertebrates changed significantly in different months, with Exopalaemon modestus being the absolute advantage species in the basin in July and September 2022. In different sampling months, the functional feeding group of macroinvertebrates was mainly dominated by shredders, accounting for 35.9%. The results of redundancy analysis showed that the main environmental factors affecting the distribution of functional feeding groups of macroinvertebrates varied across different months, with conductivity in February, temperature in July, and oxidation-reduction potential in September and November. The evaluation based on the biological index and Shannon index of macroinvertebrates indicated that water quality in the investigated section was at a light pollution level. [ABSTRACT FROM AUTHOR]

Soil fauna play an important role in key functions of ecosystem such as material cycling. Litter quality and microenvironment of different tree species may regulate soil fauna community structure. In this study, we inves-tigated soil fauna community structure, the differences of taxonomic and functional groups, and the regulatory factors under eight dominant tree species in August 2022. We captured 567 soil fauna (except for termites and ants), belonging to 3 phyla, 10 classes, 26 orders, and 99 families, with Achipteriidae, Trygoniidae, Poduridae, and Isotomidae as the dominant species. Tree species significantly affected soil fauna abundance, following an order; Michelia macclurei > Elaeocarpus decipiens > Castanopsis carlesii > Cunninghamia lanceolata > Lindera communis > Schima superba > Pinus massoniana > Liquidambar formosana. However, the richness, evenness, and diversity of soil fauna under different tree species were significantly different. Richness and diversity of M. macclurei, C. lan-ceolatas soil fauna were relatively high, while L. formosana, C. carlesii were relatively low. The evenness of meso-microfauna of L. formosana was the highest, which was significantly higher than that of M. macclureis and E. decipiens. The evenness of macrofauna and total soil fauna was not significantly different among the eight tree species. In addition, the abundance of omnivores and herbivores soil fauna was relatively high under M. macclurei, but relatively low under E. decipiens. The abundance of saprophages and predators soil fauna of E. decipiens, M. macclurei was higher than L. formosana, while saprophages was mainly meso-microfauna. Results of redundancy analysis showed that litter N, C:N, and K were the main factors affecting soil fauna community structure. The results indicated that the tree species with thicker litter layer and higher N and K contents may be conducive to enhancing the diversity of soil fauna community and affecting the distribution of different functional groups, thus contributing to the maintenance of forest biodiversity. [ABSTRACT FROM AUTHOR]

To explore the spider species diversity and its environmental associations on artificial grasslands in karst areas, we investigated the species diversity of spider in the New Zealand pasture of the Youshanhe in northwestern Guizhou Province, using sampling, trap, and line sampling methods, and further assessed species diversity–environment relationship. The results of the study showed: (1)1642 spiders, belonging to 15 families, 53 genera, and 69 species, were collected. The order of different functional groups was: Round-web spiders > Ambush spiders > wandering-spiders > Net-type spiders. The dominant four families were Araneidae (25.15% of all species), Theridiidae (20.52% of all species), Philodromidae (15.1% of all species), and Thomisidae (13.28% of all species). Furthermore, the two dominant species were Araneus diffinis (17.17% of all individuals) and Philodromus fallax (14.49% of all individuals). (2) The number of individual spiders, the number of species, and the Shannon-wiener index were the smallest in December, which was significantly lower than that in September, October, November and January. The spider richness index decreased first and then increased, and was the smallest in December, significantly lower than in September, October and January. (3) The linear fitting showed that altitude, air humidity, and number of vegetation species had significantly positive associations with spider abundance. (4) Canonical correspondence analysis revealed that 9 environmental factors accounted for 70.98% of the variation for spider species diversity. The vegetation Pielou index had a significantly negative associations with spider species diversity, and soil temperature and air temperature had a significant and positive effect on spider species diversity. Among them, soil temperature had the greatest impact on spider composition, with a contribution rate of 78.52%. The species diversity of spider communities on artificial grasslands in karst areas had a strong correlation with factors such as seasons, climate, and vegetation. Spiders must be closely integrated with local vegetation, climatic and soil factors to control grassland pests and diseases. [ABSTRACT FROM AUTHOR]

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为缓解化石能源压力，提高生物质能源的使用率，以空气中CO2作为自养培养斜生栅藻的碳源，添加植物激素水杨酸（SA）诱导斜生栅藻，研究斜生栅藻细胞密度、叶绿素a含量、油脂含量及产率等的变化情况，探讨在SA诱导下斜生栅藻的产脂机制。结果表明：培养16 d，SA对斜生栅藻生长及油脂积累表现出显著促进效果，当SA质量浓度为20 mg/L时，细胞密度最大，为（1.89±006）g/L，较对照组提高了34.47%；在实验范围内（SA质量浓度0～40 mg/L），油脂产率与SA质量浓度呈线性正相关；油脂含量及产率均在SA质量浓度为40 mg/L时达到最大，分别为（48.49±7.47）%和（22.35±3.77）mg/（L·d），较对照组分别提高了72.85%和1.43倍；SA对斜生栅藻细胞官能团中的酯基、羧基、磷酸基团等产生了影响；同时，在SA诱导下斜生栅藻的油脂代谢途径与叶绿素、酶、抗逆性等因素有关。综上，SA既提高了斜生栅藻的生物量，又促进了其光合作用和储能物质转化，提高了油脂产率。 In order to alleviate the pressure of fossil energy, and improve the utilization rate of biomass energy, Scenedesmus obliquus（S. obliquus）was autotrophic cultivated by using CO2 in the air as the carbon source and adding the phytohormone salicylic acid（SA）. The changes of cell density, chlorophyll a content, lipid content and productivity, and the mechanism of lipid production of S.obliquus were investigated. The results showed that SA had a significant effect on promoting the growth and lipid accumulation of S. obliquus after 16 d of culture. When the SA mass concentration was 20 mg/L, the cell density reached a maximum of (1.89±0.06) g/L, which was 34.47% higher than that of the control group. In the experimental mass concentration range (0-40 mg/L), the productivity of lipid was positively correlated with the mass concentration of SA. The lipid content and productivity reached the maximum at 40 mg/L with (48.49±7.47)% and (22.35±3.77)mg/(L·d) respectively, which were 72.85% and 1.43 times higher than that of the control group. SA had effects on ester group, carboxyl group, phosphate group, etc. in the functional groups of S. obliquus cells. At the same time, the lipid metabolism pathway of S. obliquus induced by SA was related to chlorophyll, enzymes, stress resistance and other factors. In conclusion, SA can increase the biomass of S. obliquus, promote the photosynthesis and energy storage material conversion of S. obliquus, and improve the lipid productivity.

Copyright of Journal of Dalian Ocean University is the property of Journal of Dalian Ocean University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Flotation is an important method for the separation of fine materials.The type of frothers and the stability of the foam significantly affect flotation performance.In this paper, three foaming agents of alcohols (MIBC), esters (DEP) and ether alcohols (DGBE) are selected to investigate the effect of functional groups in frothers on foaming performance and foam stability.Foamscan was used in the experiment to determine the foaming performance and foam stability of the frothers, and the Tracker rheometer was used to determine surface tension and the viscoelastic modulus of the air-liquid interface.Results show that the foaming rate increases linearly with the decrease of surface tension.It reaches its peak/the maximum when the gas-liquid interface adsorbs the foaming agent to saturation, and when the adsorption of the foaming agent on the gas-liquid interface reaches saturation.The foaming rate of MIBC reaches its peak/the maximum and that of DGBE its trough/the minumum.When the concentration of the frother reaches the critical mass fraction, the foaming ability reaches its peak/the maximum, and the critical mass fractions of MIBC, DEP and DGBE are 1.1 %, 0.4 % and 0.8 %.The size of the bubbles decreases with the decrease of the surface tension of the solution, and the order of the average bubble size from large to small is: DGBE>DEP>MIBC.The ether alcohol frothers have the strongest foam stability, while the alcohol frothers have the worst foam stability.The foam is the most stable.when the mass fractions of MIBC, DEP and DGBE are 0.4 %, 0.5 % and 0.8 %.

There are six horseshoe crab marine protected areas (MPAs) in Guangdong Province. However, the baseline information on distribution, size and trend of horseshoe crab populations is virtually unknown. The lack of information has hindered the formulation of scientific management strategies and conservation actions. In this study, field surveys were conducted to investigate the current status of horseshoe crab populations in each of the six MPAs, and to analyze the macrobenthic communities in the intertidal zone. The results showed that juvenile horseshoe crabs were only found in Suixi Chinese horseshoe crab and Xuwen mangrove horseshoe crab MPAs. The abundance of the juveniles within Xuwen MPA was considerably low, i.e., only two juveniles were found. The abundance in Suixi MPAs was 6.45 ind·100 m–2, but the number of individuals in young size group was much lower compared to that of elder groups. The analysis of functional groups of macrobenthos in the MPAs intertidal areas demonstrated that those from Suixi were mainly plankton feeders, while those from Xuwen were primarily phytoplankton feeders. Plankton, microalgae, phytoplankton and other natural food sources are abundantly available, which can fulfill the feeding requirements of the juveniles. The population surveys within the horseshoe crab MPAs revealed the unsatisfactory situation of horseshoe crabs in Guangdong Province, and the management of these MPAs should be improved urgently. Conservation actions such as upgrading the protection level of the horseshoe crab, establishing scientifically-sound restocking program and effective management measures are imperatively required. [ABSTRACT FROM AUTHOR]

[Objectives] In order to compare the effects of different plant fibers on the properties of polylactic acid (PLA) composites, three kinds of plant fibers with better properties: rice husk, reed straw and bamboo were used to prepare high content plant fiber/PLA composites (50% plant fiber content). [Methods] The composition of the plant fiber was analyzed. The functional groups and micromorphology of the plant fiber/PLA composite were observed. The mechanical properties, water barrier property and thermal stability of the PLA composites were determined. [Results]Bamboo fiber/PLA composite had the best comprehensive mechanical properties, its flexural strength was 91.37 MPa, which was 17.18% and 40.33% higher than rice husk and reed straw fiber/PLA composite, and its impact strength was 5.06 kJ·m-2, which was 9.49% and 53.56% higher than rice husk and reed straw fiber/PLA composite. The microstructure of bamboo fiber/PLA composite was the densest, and the combination of fiber and PLA was the best. The results showed that the water resistance and thermal stability of the PLA composites were reduced by filling with plant fiber, while the bamboo fiber/PLA composites had better water resistance and heat resistance. [Conclusions] Among the three kinds of high content plant fiber composites, bamboo fiber composite has the best comprehensive performance, which lays a foundation for further expanding the application of PLA composite. [ABSTRACT FROM AUTHOR]

BACKGROUND: Due to its easy modification characteristics, how to use various modification methods to obtain a scaffold that meets the requirements of tissue engineering cartilage repair has become the focus of current research. OBJECTIVE: To review characteristics of hyaluronic acid cartilage repair scaffolds modified by various modification methods and their advantages and applications in cartilage tissue engineering. METHODS: A computer search of the articles concerning hyaluronic acid cartilage repair scaffolds on CNKI, Wanfang, VIP, and PubMed databases was conducted from January 2011 to March 2021. The “hyaluronic acid, cartilage, scaffold, tissue engineering” in Chinese and English were used as search terms. Finally, 72 articles were included for analysis. RESULTS AND CONCLUSION: (1) The modifiability of hyaluronic acid provides an important application strategy for efficient and high-quality cartilage repair. At present, many related researches have achieved remarkable results. Carboxyl modified hyaluronic acid scaffolds can improve the survival rate and metabolic activity of seed cells, and have good biocompatibility. Hydroxy modified hyaluronic acid scaffold has good mechanical properties and biodegradability. The acetamino modification of hyaluronic acid was not used for cartilage repair because of the toxicity of the deacetylation reagent. The grafted hyaluronic acid scaffold can repair cartilage and subchondral bone, and up regulate cartilage gene expression. The composite modified hyaluronic acid scaffold has excellent spatial structure, which can regulate the directional differentiation of seed cells and inhibit hypertrophy, and it is a multifunctional scaffold. (2) However, hyaluronic acid based scaffolds still face some objective problems and different challenges in cartilage repair, for example, hyaluronic acid based scaffolds cannot completely regenerate hyaluronic cartilage at present. Most of the researches are in the animal experimental stage, and the number of clinical researches is quite limited. (3) In recent years, the design strategy of cartilage tissue engineering scaffolds has changed to the direction of annexing cartilage and subchondral bone repair. The multifunctional scaffold based on hyaluronic acid will be the key to achieve high-quality cartilage repair in the future. [ABSTRACT FROM AUTHOR]

The research on improving the adhesive property of addition-type liquid silicone rubber to the substrate at home and abroad in recent years were reviewed with 28 references, and those researches mainly included surface treatment of the substrate, introducing functional groups into the polyorganosiloxane molecular chain, adding adhesion promoter containing functional groups, and adding primer coat layer between the rubber and the substrate, and the advantages and disadvantages of various methods were also analyzed. What′s more, it was pointed out that the development direction of the research on the adhesion performance of addition-type liquid silicone rubber in the future was the development of various functional adhesion promoters.

The experiment of electric pulse cracking of anthracite coal from Jiaozishan Coal Mine in Guizhou Province was carried out by using the electric pulse experimental system of fracturing and enhancing permeability of coal. Combined with industrial analysis, Fourier infrared spectroscopy and isothermal adsorption experimental methods, the changes of peak current, coal functional group structure and methane adsorption capacity under different breakdown voltages were studied. The results show that the process of electrical pulse breakdown of coal samples mainly goes through thermal breakdown, electrical breakdown and residual stages. Meanwhile, the peak current of breakdown coal samples increases with the increase of breakdown voltage and presents an exponential trend. The functional group structure of coal treated with electric pulse changes obviously, the CH absorption peak increases with the increase of breakdown voltage, while the absorption peaks of C=C, -CH3, -CH2 and -OH decrease. The limit adsorption capacity a value of high-voltage pulse impact coal is lower than that of raw coal, and the adsorption constant b value fluctuates with the increase of breakdown voltage, indicating that after coal treated with electric pulse, the adsorption capacity of coal is significantly reduced, which is conducive to the efficient exploitation of coalbed methane.

In order to study the transformation law of the most essential active groups in the process of coal spontaneous combustion and low-temperature oxidation, the Fourier in-situ infrared measurement technology was used to obtain the distribution of the main functional groups of the raw coal, and the key active groups in the coal were obtained by peak fitting. The content changes during the heating process under different atmospheres were compared, and the active group conversion curve representing the intrinsic coal-oxygen recombination reaction was obtained by using the subtraction map. The results show that the content of -CH3 and -CH2- in the air atmosphere decreases overall, and the content conversion rate of -COOH with the increase of temperature is less than that of C=O; the net difference of the content change of -COOH under pyrolysis in nitrogen atmosphere is the largest; in the coal-oxygen recombination reaction, the overall decrease in the content of active groups is due to the fact that the consumption rate of the oxidation reaction is greater than the production rate; the coal oxidation reaction rate began to increase gradually from 60 ℃to 70 ℃, and it was found that the decrease of the overall content of four key active groups provided conditions for the low-temperature oxidation reaction of coal samples.

The intensity of air leakage not only increases the risk of spontaneous combustion of coal, but also is the cause of coal fire disasters caused by spontaneous combustion of coal left in the goaf. Aim to find the influence of the air leakage intensity on the spontaneous combustion characteristics of the remaining coal when the fire zone is opened, the coal spontaneous combustion characteristics measuring device is used to conduct a temperature-programming experiment on the coal samples, and then Fourier transform infrared spectroscopy(FTIR) is used for analysis to obtain different gas environments. The relative content of functional groups changes at each characteristic temperature point. The results show that in the oxygen-containing groups, the content of -COOH increases as the temperature rises. Although the change range of -C-O- is not obvious with the rise of the temperature point, its content is relatively high; in the functional groups of -OH, it is present at all temperature stages. It exists and the peak intensity is obvious; among the aliphatic hydrocarbons, the peak areas of -CH3 and -CH2 are both large, and both dry air and nitrogen atmosphere participate in the reaction at various temperature points, and the activity is high. Through structural parameter value analysis, T120 is the key active point temperature. In the coal sample that is naturally cooled under dry air or nitrogen atmosphere, the functional groups of the raw coal react more violently in T120, and the functional groups change more. As a whole, the increasing and decreasing trend of functional group changes in nitrogen atmosphere is smaller than that in dry air atmosphere, and the risk of coal re-ignition is also reduced.

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Copyright of China Plastics / Zhongguo Suliao is the property of Journal Office of CHINA PLASTICS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

【Objective】The study aimed to explore response of species diversity and functional group characteristics of typical steppe communities to different management methods in west Wuzhunuqin banner.【Method】Four grassland management methods, namely grazing and mowing grassland(MG), summer grassland(SG), winter grassland(WG) and no grazing and mowing grassland(MP), were selected to compare the species diversity and functional group characteristics of grassland community.【Result】The species composition of grazing grassland in summer was single, and the number of species was significantly lower than that of other management methods. The height, coverage, density and species number of grassland community in summer were significantly lower than those of other management methods, and there were degradation indicator species; There was a significant difference between winter grassland and grazing forbidden grassland(q=0.24). The average litter content of grazing grassland was in the order of no-grazing pasture > grazing pasture > summer grazing pasture > winter grazing pasture, and the litter content of winter grazing pasture was significantly lower than that of other grazing pasture(P<0.05). There was a negative correlation between Margalef abundance and litter content of winter grazing pasture. Shannon-wiener diversity index and Simpson dominance index of grassland in summer were significantly lower than those of other management methods(P<0.05). The richness index, evenness and aboveground biomass of grazing and mowing grassland were significantly higher than those of other management methods(P<0.05). At the same time, mowing grassland reduced the important value of dominant species, which was 7.59% less than that of no grazing and mowing grassland, increased the important value of perennial weeds and perennial herbs, which was conducive to the stability of the community.【Conclusion】Grassland degradation in summer is not conducive to the healthy development of grassland, so the grazing intensity should be reduced. Grazing prohibition and winter grassland can be properly utilized. Mowing and grazing combined treatment is more conducive to the sustainable development of typical grassland. [ABSTRACT FROM AUTHOR]

Soil fungi are important components of belowground biodiversity and play important roles in soil carbon and nutrient cycling. We investigated fungal communities in the top soil (0-10 cm) of 22 Pinus massoniana forests in the Three Gorges Reservoir Region using high-throughput sequencing technique. We found that Ascomycota and Basidiomycota were the dominant fungi phyla, and Eurotiales, Russulales, and Tremellales were the most abundant fungi orders. The dominant functional groups in P. massoniana forests were saprophytic fungi, ectomycorrhizal fungi, and ericoid mycorrhizal fungi. Results of redundancy analysis showed that environmental variables but not spatial variables were the main drivers of soil fungal community structure across the 22 P. massoniana forests, which suggested that habitat filtering rather than dispersal limitation shaped soil fungal community structure. Aboveground biomass, soil conductivity, available phosphorus, soil bulk density, carbon to nitrogen ratio, nitrate concentration, and proportion of slit were the main factors explaining the variation in soil fungal community structure. It should be noted that the key factors influencing different fungal functional groups differed across forests. [ABSTRACT FROM AUTHOR]

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In order to investigate the evolution law of the functional groups of pre-oxidized coal samples, lignite from Liujia and Sitai, bituminous coal from Tongxin and anthracite from Baijigou were pre-oxidized at 50 ℃, 120 ℃ and 200 ℃ for 6 h. Fourier transform infrared spectrometer was used to test the infrared spectrum of both original and pre-oxidized coal samples. The evolution law of functional groups on the coal surface was obtained. the results showed that: pre-oxidation did not change the type of functional groups, which only changed the amounts of functional groups; The higher is the pre-oxidation temperature, the more functional groups of -OH were involved in the reaction. The absorbance of the -OH decreased 51.43% after the pre-oxidization at 200 ℃, which suggested that the pre-oxidation had more effects on the low metamorphic degree coal; as the pre-oxidation temperature increased, the functional groups of -CH2-, -CH3 and -C=O increased first, and then decreased. For coal samples pre-oxidized at 50 ℃, the amounts of -CH2-, -CH3 and -C=O increased after pre-oxidation; for coal samples pre-oxidized at 120 ℃ and 200 ℃, the amounts of -CH2-, -CH3 and -C=O decreased after pre-oxidation. When the pre-oxidized coal samples were re-oxidized, compared with the original coal samples, the coal samples pre-oxidized at 50 ℃ generated more gases of CO, CO2, C2H4 and C2H6 at a lower temperature, while the coal samples pre-oxidized at 120 ℃ and 200℃ generated less gases at ahigher temperature.

CO gas, as a marker gas in the whole process of coal spontaneous combustion, plays a very important role in the prediction of coal spontaneous combustion. However, a large amount of CO gas can be generated under normal conditions of low-metamorphic coal, which interferes with the prediction of coal spontaneous combustion in low-metamorphic coal seam mining area. Coal samples were collected from five typical mines in Gushan Mine in Pingzhuang, Bulianta Coal Mine in Shendong, Daliuta Coal Mine in Shenmu Mining Area in Shaanxi, Zaoquan Mine in Lingwu Mining Area in Ningxia, and No.1 Mine in Dananhu Mine in Dananhu Mining area in Xinjiang. After oxygen isolation crushing treatment, the CO generation law of coal samples in 5 mining areas during oxygen isolation heating process was studied by using oxygen isolation program heating and Fourier optical interference experiment, and the types of active functional groups on coal molecules with or without oxygen separation heating were analyzed. It was believed that carbonyl (C=O), carboxyl (-COOh), ether (-O-CH3) and other oxygen-containing groups on coal molecules were directly related to the generation of CO gases in low-metamorphism coal at room temperature.

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The study of soil bacterial community structure and functional groups in rice terraces can provide a theoretical basis for the sustainable management of terraces. Nineteen soil samples were collected at different altitudes in Longji rice terraces. Bacterial community structure was analyzed using 16S rRNA high-throughput sequencing, and its functional group was predicted using FAPROTAX functional prediction software. The results showed that the dominant phyla were Proteobacteria and Chloroflexi with 37.40%~63.28% and 11.30%~ 40.78% abundance, respectively. The dominant genera were Sphingomonas and Rhodanobacter with 7.13%~20.87% and 2.34%~21.53% abundance, respectively. Clustering heatmap of dominance operational taxonomic units（OTUs）showed that the environmental factors significantly related to bacterial abundance were pH, carbon–nitrogen ratio（C/N）, alkali-hydrolyzed nitrogen（AN）, and altitude. A total of 51 functional groups were predicted based on all the OTUs. Denitrification, sulfur respiration, and hydrocarbon degradation functional groups were significantly related to pH, C/N, AN, and altitude. The above results indicated that soil pH, C/N, AN, and altitude significantly affected soil bacterial community structure and functional groups in Longji rice terraces. [ABSTRACT FROM AUTHOR]

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