The shear behavior of granular materials plays an important role in understanding the occurrence of geological hazards. This study introduces the use of direct shear tests and acoustic emission(AE) technology on glass...The shear behavior of granular materials plays an important role in understanding the occurrence of geological hazards. This study introduces the use of direct shear tests and acoustic emission(AE) technology on glass beads to investigate the distributions features of AE during the stick-slip processes. Results show that the shearing behavior of granular samples was shown as a series of similar, periodic stick-slip events. Some AE features — energy and Root Mean Square(RMS) —showed significant spatial clustering. Combined with the distribution of AE in the stick-slip event, the AE signal can be divided into four types: 1. low-energy and highfrequency AE, which represent particle friction;2. highenergy and low-frequency AE, which represent structural failure, that is, the slip process;3. low-RMS and lowfrequency AE represent internal local failure;and 4.high-RMS and high-frequency AE caused by overall structure failure. The b-value representing the energy distribution of AEs is used to describe the changing of AE sources during shear process. In addition, the amount and energy of AE had a significant positive correlation with normal stress. The shear rate mainly affects the AE representing particle friction, and the faster the shear rate, the lower the incidence of these friction AEs. According to the time sequence of the occurrence of different types of AE, AE rate, b-value and local failure AE signal can be applied to the prediction or early warning of geological hazards.展开更多
Based on the theory of complex adaptive system(CAS),the optimal allocation model of water resources in sewage irrigation areas was established,which provided new ideas and application value for the rational utilizatio...Based on the theory of complex adaptive system(CAS),the optimal allocation model of water resources in sewage irrigation areas was established,which provided new ideas and application value for the rational utilization of agricultural production and waste water resources.The results demonstrated that the difference of crop energy capture mainly depended on the development stage.Waste water with a certain concentration was able to promote crop growth,while excessive concentration inhibited crop growth.The correlation between water absorption rate and leaf area index was close(R=0.9498,p<0.01).The amount of bad seeds increased at a speed of 34.7·d^-1,when system irrigated randomly in the seedling stage,while it tended to remain stable at a speed of 0.3·d^-1 after plants entering the mature stage which impacted the total yields of crops.展开更多
基金Supported by the Zhejiang Provincial Natural Science Foundation of China(Y3110477)the Research Project of Lishui Science and Technology Bureau(2018RC01)。
基金funded by the National Nature Science Foundation of China Grants (41807278,41790432,U20A20112)the Strategic Priority Research Program of the Chinese Academy of Sciences Grant (No.XDA23090202)+2 种基金the Key Research Program of Frontier Sciences,Chinese Academy of Sciences Grant (No.QYZDY-SSWDQC006)support from the CAS Pioneer Hundred Talents Programthe China-Pakistan Joint Research Center on Earth Sciences。
文摘The shear behavior of granular materials plays an important role in understanding the occurrence of geological hazards. This study introduces the use of direct shear tests and acoustic emission(AE) technology on glass beads to investigate the distributions features of AE during the stick-slip processes. Results show that the shearing behavior of granular samples was shown as a series of similar, periodic stick-slip events. Some AE features — energy and Root Mean Square(RMS) —showed significant spatial clustering. Combined with the distribution of AE in the stick-slip event, the AE signal can be divided into four types: 1. low-energy and highfrequency AE, which represent particle friction;2. highenergy and low-frequency AE, which represent structural failure, that is, the slip process;3. low-RMS and lowfrequency AE represent internal local failure;and 4.high-RMS and high-frequency AE caused by overall structure failure. The b-value representing the energy distribution of AEs is used to describe the changing of AE sources during shear process. In addition, the amount and energy of AE had a significant positive correlation with normal stress. The shear rate mainly affects the AE representing particle friction, and the faster the shear rate, the lower the incidence of these friction AEs. According to the time sequence of the occurrence of different types of AE, AE rate, b-value and local failure AE signal can be applied to the prediction or early warning of geological hazards.
基金Supported by the Science and Technology Research Project of the Ministry of Education(14YJCZH017)the Major State Basic Research Development Program of China(973 Program)(2017YFC0404503)+1 种基金Key Cultivation Project of Lingnan Normal University in 2019(LZ1903)Lingnan Normal University Special Talent Program(ZL2007)
文摘Based on the theory of complex adaptive system(CAS),the optimal allocation model of water resources in sewage irrigation areas was established,which provided new ideas and application value for the rational utilization of agricultural production and waste water resources.The results demonstrated that the difference of crop energy capture mainly depended on the development stage.Waste water with a certain concentration was able to promote crop growth,while excessive concentration inhibited crop growth.The correlation between water absorption rate and leaf area index was close(R=0.9498,p<0.01).The amount of bad seeds increased at a speed of 34.7·d^-1,when system irrigated randomly in the seedling stage,while it tended to remain stable at a speed of 0.3·d^-1 after plants entering the mature stage which impacted the total yields of crops.
基金This work was supported by the National Natural Science Foundation of China(No.31500964)the Fok Ying Tung Education Foundation(No.151095)the Fundamental Research Funds for the Central Universities(No.2020023)。
文摘本文旨在探讨不同时长、不同强度运动对大鼠骨骼肌线粒体功能和自噬的影响及FUNDC1的作用。选取60只雄性SD大鼠随机分为2周、4周的安静对照组(Con组)、中等强度运动组(M-ex组,跑台运动16 m/min,1 h/d,6 d/week)和大强度运动组(Hi-ex组,跑台运动35 m/min,20 min/d,6 d/week),每组10只。干预结束后分离双侧比目鱼肌,石蜡切片制备透射电镜样本,用ELISA检测柠檬酸合成酶(citrate synthase, CS)的含量,用冰冻切片免疫荧光染色法观察微管相关蛋白1轻链3 (microtubule-associated protein 1 light chain 3, LC3)/细胞色素c氧化酶IV亚型(cytochrome c oxidase IV, COX-IV)、FUNDC1/COX-IV及LC3/FUNDC1的共定位情况。提取骨骼肌线粒体,用Western blot检测过氧化物酶体增殖物激活受体γ共激活因子-1α(peroxisome proliferator-activated receptorγco-activator-1α, PGC-1α)、COX-I、腺苷酸活化蛋白激酶α(AMP-activated protein kinaseα,AMPKα)、p-AMPKα、Unc-51样激酶1 (Unc-51 like kinase 1, ULK1)、FUNDC1、LC3、自噬选择性底物(p62)等自噬相关蛋白表达。结果显示,运动可上调线粒体功能,即PGC-1α、COX-I蛋白表达和CS含量,2周Hi-ex组和2周M-ex组之间无差异,而4周Hi-ex组显著低于4周M-ex组。在运动强度相同的情况下,4周运动组大鼠的骨骼肌线粒体自噬激活程度高于2周运动组;在运动时长相同的情况下,Hi-ex组的线粒体自噬激活程度高于M-ex组。2和4周运动干预均可提高LC3/COX-IV、COX-IV/FUNDC1、FUNDC1/LC3共定位。运动可提高LC3-II/LC3-I比值,下调p62蛋白表达水平,上调FUNDC1、ULK1蛋白表达水平和AMPKα磷酸化水平,4周Hi-ex组的这些蛋白表达变化幅度显著大于4周M-ex组。以上结果提示,运动可诱导骨骼肌线粒体自噬,自噬的激活程度与运动时间和强度有关,运动的诱导机制可能是通过AMPK-ULK1通路影响FUNDC1的表达。
