Granitic samples from Zhejiang Province, Southeast of China, were tested in a uniaxial condition to failure at constant confining pressure. It is found from careful Scanning Electron Microscope (SEM) observations that...Granitic samples from Zhejiang Province, Southeast of China, were tested in a uniaxial condition to failure at constant confining pressure. It is found from careful Scanning Electron Microscope (SEM) observations that fractures form the intersection or coalescence of microcavities. Granite consists of three major minerals, Quartz, feldspar (K-feldspar & Plagioclase) and biotite. The cracks in various minerals of the specimen develop differently; this obvious difference in crack patterns is believed to result from the nature of their microstructures. Careful observation shows that quartz display brittle and isotropic crack while feldspar and biotite exhibit anisotropic cracks and the separating of their cleavage planes (cleavage cracks) is the one of the major failure forms of biotite and feldspar. From the tectonic point of view, the granite has been strongly deformed and hydrothermally altered; such hydrothermal fluids may be keep the system open for fluid movement to cause alteration metasomatism of granite.展开更多
Shear tab connections or simple connections are widely used in structural steel structures. There are several limit states associated with these connections such bolt shear, bolt bearing, block shear, shear yielding a...Shear tab connections or simple connections are widely used in structural steel structures. There are several limit states associated with these connections such bolt shear, bolt bearing, block shear, shear yielding and shear rupture. A modified version of the shear tab has been developed during the last decade, which is extended shear tab connections. In developing design provisions for the extended shear tab connections, experimental work showed that there are additional limit states other than those mentioned above that limit the capacity of the extended shear connection. Extended shear tab connections could be used to frame beam-to-column or beam-to-girder. In the case where a beam is framed into girder, a new limit state develops in the web of the supporting girder. This limit state is punching shear of the supporting girder web which is due to a higher moment. The higher moment in extended shear tab connections is due to the larger moment arm （eccentricity） from the bolt line, the location of the shear force, to the support, which is in this case the girder＇s web. This study investigates the supporting girder web using experimental work, finite element analysis, and yield line theory. This paper shows the result of this investigation and proposes an evaluation of the web capacity equation which should be used when calculating the beam-to-girder connection capacity.展开更多
Dynamic collapses of deeply mined coal rocks are severe. In order to explore new ideas for rock burst pre- vention, the relationship between entropy equations and dissipative structure was studied, and a con- cept-roc...Dynamic collapses of deeply mined coal rocks are severe. In order to explore new ideas for rock burst pre- vention, the relationship between entropy equations and dissipative structure was studied, and a con- cept-rock burst activity system （RAS） was proposed and its entropy was analyzed. The energy features of RAS were analyzed, and the relationship between electromagnetic radiation （EMR） intensity E and dis- sipated energy Ud was initially established. We suggest that rock burst normally happens only when d1S - 〈〈 -des in RAS; RAS is the dissipative structure before collapse, and after which it become a new orderly structure, i.e., a ＂dead＂, a statically orderly structure. We advanced that the effective way to prevent rock burst is to introduce entropy to the system for it keeps the system away from the dissipative structure. E and Ud of RAS are positively related, which is used as a bridge between dissipative structure theory and rock burst prevention engineering applications. Based on this, and using the data of rock burst prevention for working face No. 250205up of Yanbei coal mine, an engineering verification for the dissipative struc- ture of RAS was carried out. which showed good results.展开更多
Whether the breakdown structure and coding system of construction projects are reasonable or not determines to a large degree the performance level of the entire project management. We analyze in detail the similariti...Whether the breakdown structure and coding system of construction projects are reasonable or not determines to a large degree the performance level of the entire project management. We analyze in detail the similarities and differences of two kinds of decomposing methods classified by type of work and construction elements based on the discussion of international typical coding standards system designing. We then deduce the differential coefficient relation between project breakdown structure (PBS) and work breakdown structure (WBS). At the same time we constitute a comprehensive construction project breakdown system including element code and type of work code and make a further schematic presentation of the implementation of the system’s functions.展开更多
The seismic safety of nuclear power plan(tNPP)has always been a major consideration in the site selection,design,operation,and more recently recertification of existing installations. In addition to the actual NPP and...The seismic safety of nuclear power plan(tNPP)has always been a major consideration in the site selection,design,operation,and more recently recertification of existing installations. In addition to the actual NPP and all their operational and safety related support systems,the storage of spent fuel in temporary or permanent storage facilities also poses a seismic risk. This seismic risk is typically assessed with state-of-the-art modeling and analytical tools that capture everything from the ground rupture or source of the earthquake to the site specific ground shaking,taking geotechnical parameters and soilfoundationstructureinteraction (SFSI) into account to the non-linear structural response of the reactor core,the containment structure,the core cooling system and the emergency cooling system(s),to support systems,piping systems and non-structural components,and finally the performance of spent fuel storage in the probabilistically determined operational basis earthquake (OBE) or the safe shutdown earthquake (SSE) scenario. The best and most meaningful validation and verification of these advanced analytical tools is in the form of full or very large scale experimental testing,designed and conducted in direct support of model and analysis tool calibration. This paper outlines the principles under which such calibration testing should be conducted and illustrates with examples the kind of testing and parameter evaluation required.展开更多
At GMT time 13：19, August 8, 2017, an M1.0 earthquake struck the Jiuzhaigou region in Sichuan Province, China, causing severe damages and casualties. To investigate the source properties, seismogenic structures, and ...At GMT time 13：19, August 8, 2017, an M1.0 earthquake struck the Jiuzhaigou region in Sichuan Province, China, causing severe damages and casualties. To investigate the source properties, seismogenic structures, and seismic hazards, we systematically analyzed the tectonic environment, crustal velocity structure in the source region, source parameters and rupture process, Coulomb failure stress changes, and 3-D features of the rupture plane of the Jiuzhaigou earthquake. Our results indicate the following： （1） The Jiuzhaigou earthquake occurred on an unmarked fault belonging to the transition zone of the east Kunlun fault system and is located northwest of the Huya fault. （2） Both the mainshock and aftershock rupture zones are located in a region where crustal seismic velocity changes dramatically. Southeast to the source region, shear wave velocity at the middle to lower crust is significantly low, but it rapidly increases northeastward and lies close to the background velocity across the rupture fault. （3） The aftershock zone is narrow and distributes along the northwest-southeast trend, and most aftershocks occur within a depth range of 5-20 km. （4） The focal mechanism of the Jiuzhaigou earthquake indicates a left-lateral strike-slip fault, with strike, dip, and rake angles of 152~, 74~ and 8~, respectively. The hypocenter depth measures 20 km, whereas the centroid depth is about 6 kin. The co-seismic rupture mainly concentrates at depths of 3-13 km, with a moment magnitude （Mw） of 6.5. （5） The co-seismic rupture also strengthens the Coulomb failure stress at the two ends of the rupture fault and the east segment of the Tazang fault. Aftershocks relocation results together with geological surveys indicate that the causative fault is a near vertical fault with notable spatial variations： dip angle varies within 660-89~ from northwest to southeast and the average dip angle measures -84~. The results of this work are of fundamental importance for further studies on the source characteristics, tectonic environment, and seismic hazard evaluation of the Jiuzhaigou earthquake.展开更多
Patients suffering from zygomatic complex fractures always present facial deformity and dyslunctions, and thereafter develop psychological and physiological problems. It is really hard to get an ideal prog- nosis for ...Patients suffering from zygomatic complex fractures always present facial deformity and dyslunctions, and thereafter develop psychological and physiological problems. It is really hard to get an ideal prog- nosis for the zygomatic complex fractures because of the complicated anatomical structures. Computer- assisted surgery techniques, as the new emerging auxiliary methods, can optimize the surgical protocol, predict operation outcomes, and improve the accuracy and quality of the operation. Meanwhile the postoperative complications can be reduced effectively. This review aims to provide a comprehensive overview of the application of computer-assisted surgery techniques in the management of zygomatic complex fractures.展开更多
文摘Granitic samples from Zhejiang Province, Southeast of China, were tested in a uniaxial condition to failure at constant confining pressure. It is found from careful Scanning Electron Microscope (SEM) observations that fractures form the intersection or coalescence of microcavities. Granite consists of three major minerals, Quartz, feldspar (K-feldspar & Plagioclase) and biotite. The cracks in various minerals of the specimen develop differently; this obvious difference in crack patterns is believed to result from the nature of their microstructures. Careful observation shows that quartz display brittle and isotropic crack while feldspar and biotite exhibit anisotropic cracks and the separating of their cleavage planes (cleavage cracks) is the one of the major failure forms of biotite and feldspar. From the tectonic point of view, the granite has been strongly deformed and hydrothermally altered; such hydrothermal fluids may be keep the system open for fluid movement to cause alteration metasomatism of granite.
文摘Shear tab connections or simple connections are widely used in structural steel structures. There are several limit states associated with these connections such bolt shear, bolt bearing, block shear, shear yielding and shear rupture. A modified version of the shear tab has been developed during the last decade, which is extended shear tab connections. In developing design provisions for the extended shear tab connections, experimental work showed that there are additional limit states other than those mentioned above that limit the capacity of the extended shear connection. Extended shear tab connections could be used to frame beam-to-column or beam-to-girder. In the case where a beam is framed into girder, a new limit state develops in the web of the supporting girder. This limit state is punching shear of the supporting girder web which is due to a higher moment. The higher moment in extended shear tab connections is due to the larger moment arm （eccentricity） from the bolt line, the location of the shear force, to the support, which is in this case the girder＇s web. This study investigates the supporting girder web using experimental work, finite element analysis, and yield line theory. This paper shows the result of this investigation and proposes an evaluation of the web capacity equation which should be used when calculating the beam-to-girder connection capacity.
基金supported by the Independent Research Project of State Key Lab of Coal Resources and Mine Safety (CUMT) (No.SKLCRSM09X01)the Youth Science Foundation of the National Natural Science Foundation of China (No. 50904067)the Foundation for the Author of National Excellent Doctoral Dissertation of PR China (No. 201055)
文摘Dynamic collapses of deeply mined coal rocks are severe. In order to explore new ideas for rock burst pre- vention, the relationship between entropy equations and dissipative structure was studied, and a con- cept-rock burst activity system （RAS） was proposed and its entropy was analyzed. The energy features of RAS were analyzed, and the relationship between electromagnetic radiation （EMR） intensity E and dis- sipated energy Ud was initially established. We suggest that rock burst normally happens only when d1S - 〈〈 -des in RAS; RAS is the dissipative structure before collapse, and after which it become a new orderly structure, i.e., a ＂dead＂, a statically orderly structure. We advanced that the effective way to prevent rock burst is to introduce entropy to the system for it keeps the system away from the dissipative structure. E and Ud of RAS are positively related, which is used as a bridge between dissipative structure theory and rock burst prevention engineering applications. Based on this, and using the data of rock burst prevention for working face No. 250205up of Yanbei coal mine, an engineering verification for the dissipative struc- ture of RAS was carried out. which showed good results.
文摘Whether the breakdown structure and coding system of construction projects are reasonable or not determines to a large degree the performance level of the entire project management. We analyze in detail the similarities and differences of two kinds of decomposing methods classified by type of work and construction elements based on the discussion of international typical coding standards system designing. We then deduce the differential coefficient relation between project breakdown structure (PBS) and work breakdown structure (WBS). At the same time we constitute a comprehensive construction project breakdown system including element code and type of work code and make a further schematic presentation of the implementation of the system’s functions.
文摘The seismic safety of nuclear power plan(tNPP)has always been a major consideration in the site selection,design,operation,and more recently recertification of existing installations. In addition to the actual NPP and all their operational and safety related support systems,the storage of spent fuel in temporary or permanent storage facilities also poses a seismic risk. This seismic risk is typically assessed with state-of-the-art modeling and analytical tools that capture everything from the ground rupture or source of the earthquake to the site specific ground shaking,taking geotechnical parameters and soilfoundationstructureinteraction (SFSI) into account to the non-linear structural response of the reactor core,the containment structure,the core cooling system and the emergency cooling system(s),to support systems,piping systems and non-structural components,and finally the performance of spent fuel storage in the probabilistically determined operational basis earthquake (OBE) or the safe shutdown earthquake (SSE) scenario. The best and most meaningful validation and verification of these advanced analytical tools is in the form of full or very large scale experimental testing,designed and conducted in direct support of model and analysis tool calibration. This paper outlines the principles under which such calibration testing should be conducted and illustrates with examples the kind of testing and parameter evaluation required.
基金funded by the Seismological Bureau Spark Program Project(Grant No.XH15007)the National Natural Science Foundation of China(Grant Nos.41604058,41574057,41621091)the Sichuan-Yunnan National Seismological Monitoring and Prediction Experimental Station Project(Grant No.2016CESE0204)
文摘At GMT time 13：19, August 8, 2017, an M1.0 earthquake struck the Jiuzhaigou region in Sichuan Province, China, causing severe damages and casualties. To investigate the source properties, seismogenic structures, and seismic hazards, we systematically analyzed the tectonic environment, crustal velocity structure in the source region, source parameters and rupture process, Coulomb failure stress changes, and 3-D features of the rupture plane of the Jiuzhaigou earthquake. Our results indicate the following： （1） The Jiuzhaigou earthquake occurred on an unmarked fault belonging to the transition zone of the east Kunlun fault system and is located northwest of the Huya fault. （2） Both the mainshock and aftershock rupture zones are located in a region where crustal seismic velocity changes dramatically. Southeast to the source region, shear wave velocity at the middle to lower crust is significantly low, but it rapidly increases northeastward and lies close to the background velocity across the rupture fault. （3） The aftershock zone is narrow and distributes along the northwest-southeast trend, and most aftershocks occur within a depth range of 5-20 km. （4） The focal mechanism of the Jiuzhaigou earthquake indicates a left-lateral strike-slip fault, with strike, dip, and rake angles of 152~, 74~ and 8~, respectively. The hypocenter depth measures 20 km, whereas the centroid depth is about 6 kin. The co-seismic rupture mainly concentrates at depths of 3-13 km, with a moment magnitude （Mw） of 6.5. （5） The co-seismic rupture also strengthens the Coulomb failure stress at the two ends of the rupture fault and the east segment of the Tazang fault. Aftershocks relocation results together with geological surveys indicate that the causative fault is a near vertical fault with notable spatial variations： dip angle varies within 660-89~ from northwest to southeast and the average dip angle measures -84~. The results of this work are of fundamental importance for further studies on the source characteristics, tectonic environment, and seismic hazard evaluation of the Jiuzhaigou earthquake.
文摘Patients suffering from zygomatic complex fractures always present facial deformity and dyslunctions, and thereafter develop psychological and physiological problems. It is really hard to get an ideal prog- nosis for the zygomatic complex fractures because of the complicated anatomical structures. Computer- assisted surgery techniques, as the new emerging auxiliary methods, can optimize the surgical protocol, predict operation outcomes, and improve the accuracy and quality of the operation. Meanwhile the postoperative complications can be reduced effectively. This review aims to provide a comprehensive overview of the application of computer-assisted surgery techniques in the management of zygomatic complex fractures.
