Triplophysa xuanweiensis sp.nov.,a new blind loach species from the family Nemacheilidae,is described based on specimens collected from a subterranean river in Xuanwei City,Yunnan Province,China.The new species can be...Triplophysa xuanweiensis sp.nov.,a new blind loach species from the family Nemacheilidae,is described based on specimens collected from a subterranean river in Xuanwei City,Yunnan Province,China.The new species can be distinguished from all known congeners by a combination of the following characters:eyes absent,dorsal-fin origin anterior to pelvic-fin origin,tip of pelvic fin reaching anus,dorsal fin with 7-8 branched rays,caudal fin forked with 16-18 branched rays,body scaleless and colorless,lateral line complete,and posterior chamber of air bladder well developed and connected to anterior chamber by long,slender tube.展开更多
During revision of the genus Microphysogobio Mori,1934,we discovered a new species of Huigobio from the Yangtze River Basin in China.The new species,named Huigobio heterocheilus sp.nov.,can be distinguished from its c...During revision of the genus Microphysogobio Mori,1934,we discovered a new species of Huigobio from the Yangtze River Basin in China.The new species,named Huigobio heterocheilus sp.nov.,can be distinguished from its congeners by a combination of the following characters:medial pad on lower lip not visible;ventral region scaleless before pelvic-fin insertion;lateral-line scales 39-40;caudal peduncle depth 49.2%-59.1%of length;barbel length 6.6%-10.7%of head length;black blotch between anterior margin of eye and upper lip.Using the K2P model and cytochrome b(cyt b)sequences,interspecific genetic distances between the new species and Huigobio exilicauda Jiang&Zhang,2013 and Huigobio chenhsienensis Fang,1938 were 13.2%and 15.1%,respectively.The new species is known from the upper reaches of the Xiangjiang River in the middle Yangtze River Basin.A diagnostic key for species of Huigobio Fang,1938 is provided.展开更多
Damage in a rock mass is heavily dependent on the existence and growth of joints,which are also influenced by the complex stress states induced by human activities(e.g.,tunneling and excavation).A proper representatio...Damage in a rock mass is heavily dependent on the existence and growth of joints,which are also influenced by the complex stress states induced by human activities(e.g.,tunneling and excavation).A proper representation of the loading path is essential for understanding the mechanical behaviors of rock masses.Based on the discrete element method(DEM),the influence of the loading path on the cracking process of a rock specimen containing an open flaw is examined.The effectiveness of the model is confirmed by comparing the simulation results under a uniaxial compression test to existing research findings,where wing crack initiates first and secondary cracks contribute to the failure of the specimen.Simulation results confirm that the cracking process is dependent upon both the confining pressure and the loading path.Under the axial loading test,a higher confining pressure suppresses the development of tensile wing cracks and forces the formation of secondary cracks in the form of shear bands perpendicular to the flaw.Increase of confining pressure also decreases the influence of the loading path on the cracking process.Reduction of confining pressure during an unloading test amplifies the concentration of tensile stress and ultimately promotes the appearance of a tensile splitting fracture at meso-scale.Confining pressure at the failure stage is well predicted by the Hoek-Brown failure criterion under quasi-static conditions.展开更多
基金supported by the National Natural Science Foundation of China(31972868)。
文摘Triplophysa xuanweiensis sp.nov.,a new blind loach species from the family Nemacheilidae,is described based on specimens collected from a subterranean river in Xuanwei City,Yunnan Province,China.The new species can be distinguished from all known congeners by a combination of the following characters:eyes absent,dorsal-fin origin anterior to pelvic-fin origin,tip of pelvic fin reaching anus,dorsal fin with 7-8 branched rays,caudal fin forked with 16-18 branched rays,body scaleless and colorless,lateral line complete,and posterior chamber of air bladder well developed and connected to anterior chamber by long,slender tube.
基金supported by the National Natural Science Foundation of China(31972868)National Science&Technology Fundamental Resources Investigation Program of China(2019FY101800)Sino BON-Inland Water Fish Diversity Observation Network。
文摘During revision of the genus Microphysogobio Mori,1934,we discovered a new species of Huigobio from the Yangtze River Basin in China.The new species,named Huigobio heterocheilus sp.nov.,can be distinguished from its congeners by a combination of the following characters:medial pad on lower lip not visible;ventral region scaleless before pelvic-fin insertion;lateral-line scales 39-40;caudal peduncle depth 49.2%-59.1%of length;barbel length 6.6%-10.7%of head length;black blotch between anterior margin of eye and upper lip.Using the K2P model and cytochrome b(cyt b)sequences,interspecific genetic distances between the new species and Huigobio exilicauda Jiang&Zhang,2013 and Huigobio chenhsienensis Fang,1938 were 13.2%and 15.1%,respectively.The new species is known from the upper reaches of the Xiangjiang River in the middle Yangtze River Basin.A diagnostic key for species of Huigobio Fang,1938 is provided.
基金supported by the Shandong Provincial Natural Science Foundation of China(No.ZR2020YQ44)the National Natural Science Foundation of China(No.51909138)。
文摘Damage in a rock mass is heavily dependent on the existence and growth of joints,which are also influenced by the complex stress states induced by human activities(e.g.,tunneling and excavation).A proper representation of the loading path is essential for understanding the mechanical behaviors of rock masses.Based on the discrete element method(DEM),the influence of the loading path on the cracking process of a rock specimen containing an open flaw is examined.The effectiveness of the model is confirmed by comparing the simulation results under a uniaxial compression test to existing research findings,where wing crack initiates first and secondary cracks contribute to the failure of the specimen.Simulation results confirm that the cracking process is dependent upon both the confining pressure and the loading path.Under the axial loading test,a higher confining pressure suppresses the development of tensile wing cracks and forces the formation of secondary cracks in the form of shear bands perpendicular to the flaw.Increase of confining pressure also decreases the influence of the loading path on the cracking process.Reduction of confining pressure during an unloading test amplifies the concentration of tensile stress and ultimately promotes the appearance of a tensile splitting fracture at meso-scale.Confining pressure at the failure stage is well predicted by the Hoek-Brown failure criterion under quasi-static conditions.
