Surface notches lower the stiffness of laminated strips, so they lower the buckling loads of the laminated strips, too. In this paper a new method is proposed to predict the buckling loads of the laminated strips with...Surface notches lower the stiffness of laminated strips, so they lower the buckling loads of the laminated strips, too. In this paper a new method is proposed to predict the buckling loads of the laminated strips with a surface notch. The theoretical and experimental results show that the buckling loads decrease as the depth or width of the surface notches increase; when the stacking sequence of the laminated strips is [0°/0°/+ θ/-θ/0°/0°/+θ/-θ] s , the buckling load decrease as θ increases. It proves that the method is reliable and significant.展开更多
Ceramic capillary membrane has received much attention due to its relatively high pack density and favorable mechanical strength.However,it is difficult to prepare capillary membrane on its thin support by a dip-coati...Ceramic capillary membrane has received much attention due to its relatively high pack density and favorable mechanical strength.However,it is difficult to prepare capillary membrane on its thin support by a dip-coating method.In this study,alumina microfiltration membranes were prepared on the inner surface of alumina capillary support(outer diameter 4 mm,inner diameter 2.5 mm)by a dip-coating method.Scanning electron microscopy(SEM)observation,gas bubble pressure(GBP)method and membrane permeation test were carried out to evaluate membrane performance.Two major effects in preparation of crack-free membrane,capillary filtration and film-coating,upon the thin support were studied.The as-prepared crack-free membrane presents a narrow pore size distribution,a mean pore size of about 0.6μm and a high pure water flux of 86000 L·m -2 ·h -1 ·MPa.It is proved that the membrane thickness should be sufficiently large to overcome the defects of support surface,but it is only one of the prerequisites for the formation of crack-free membrane.Furthermore,it is demonstrated that the capillary filtration effect is greatly restricted for thin capillary support with the dip-coating method and the film-coating effect plays a crucial role in the formation of crack-free membrane.展开更多
Aiming at the shallow depth seam proximity beneath a room mining goaf, due to that the shallow depth seam is exploited using the longwall mining and overlain by thin bedrock and thick loose sands, many accidents are l...Aiming at the shallow depth seam proximity beneath a room mining goaf, due to that the shallow depth seam is exploited using the longwall mining and overlain by thin bedrock and thick loose sands, many accidents are likely to occur, including roof structure instability, roof step subsidence, damages of shield supports, and the face bumps triggered by the large area roof weighting, resulting in serious threats to the safety of underground miners and equipment. This paper analyses the overlying strata movement rules for the shallow seams using the physical simulation, the 3DEC numerical simulation and the field mea- surements. The results show that, in shallow seam mining, the overburden movement forms caved zone and fractured zone, the cracks develop continuously and reach the surface with the face advancing, and the development of surface cracks generally goes through four stages. With the application of loose blast- ing of residual pillars, reasonable mining height, and roof support and management, the safe, efficient and high recovery rate mining has been achieved in the shallow depth seam proximity beneath a room min ing goal.展开更多
Multiple surface cracks and interfacial delamination are the major failure mechanisms in film/substrate systems.The effect of interlayer upon the failure mechanisms of interfacial delamination concomitant to surface c...Multiple surface cracks and interfacial delamination are the major failure mechanisms in film/substrate systems.The effect of interlayer upon the failure mechanisms of interfacial delamination concomitant to surface crack was explored.Finite element model was developed to obtain the stress and energy release rate(ERR),which governs the propagation of interface cracks.The dependences of delamination upon the geometry and constitutive properties of interlayer were examined.The results indicate that the effect of elastic modulus of interlayer on the steady state ERR is insignificant.In cases of different geometrical parameters,however,the steady ERR decreases with the increase of the interlayer thickness.These findings lead to the conclusion that the interlayer constraint has significant effect on the ERR and thus coating life,which can be adopted to modify the ceramic top coat.展开更多
In the present work, uranium concentrations were measured in twenty surface soil samples forselected regions in AI-Anbargovernorate using fission track etch technique, CR-39 track detector was used for registration of...In the present work, uranium concentrations were measured in twenty surface soil samples forselected regions in AI-Anbargovernorate using fission track etch technique, CR-39 track detector was used for registration of induced fission tracks. The results show that, the uranium concentrations ranged from 4.61 ppm, 56.93 Bq/kg （AL-Falluja AL-Jolan District） to 1.81 ppm 22.35 Bq/kg （Anah）with an average 3.42±0.79 ppm, 41.76±9.04 Bq/kg. The present results have shown that the uranium concentrations in the studied surface soil samples were less than the allowed limit 11.7 ppm recommended by UNSCEAR, 1993.展开更多
Madoi-Gade fault is an active fault in the Bayan Har block. According to field investigation, there is an earthquake surface rupture fairly well preserved on the Gade segment of the Madoi-Gade fault zone. The length o...Madoi-Gade fault is an active fault in the Bayan Har block. According to field investigation, there is an earthquake surface rupture fairly well preserved on the Gade segment of the Madoi-Gade fault zone. The length of the rupture is approximately 50km, with a general strike of NW. The maximum horizontal sinistral displacement is about 7.6m and the maximum vertical displacement is about 4m. A large number of earthquake traces are to be found along the rupture zone, and the phenomena on the surface rupture are also various. Field investigation and analysis on the geological and geomorphological phenomena show that the formation age of the surface rupture is relatively young. A series of linear arranged, triangular facets, fault scarps, fault springs, dislocated gullies, twisted mountain ridges, sag-ponds, dislocated ridges, etc. exist along the fault. Based on the analysis of field investigation and the data available, we believe that the surface rupture is due to a strong earthquake in the history of this area. And it is inferred that the Madoi- Gade fault within the Bayan Har block has been highly active since Late Quaternary and may still be active nowadays.展开更多
The M8.0 Wenchuan earthquake occurred on the Longmenshan fault zone. Based on field investigation of the surface rupture and focal mechanism study of the aftershocks, we discuss the geological relationship of the main...The M8.0 Wenchuan earthquake occurred on the Longmenshan fault zone. Based on field investigation of the surface rupture and focal mechanism study of the aftershocks, we discuss the geological relationship of the main, secondary and triggered ruptures. The main rupture is about 200km long and can be divided into the south part and the north part. The south part consists of two parallel fault zones characterized by reverse faulting, with several parallel secondary ruptures on the hanging wall of the main fault, and the north part is a single main fault zone characterized by lateral strike-slip and reverse faulting. Compared to a 300km long aftershock distribution, the surface rupture only occupies 200km, and the remaining lOOkm on the northeast of the main rupture was triggered by aftershocks. Study on the ruptures of this earthquake will be useful for studying the earthquake risk evolution on the Longmenshan fault system.展开更多
Composite borehole profiling combined with trenching is an effective way to acquire evidence of past ruptures of buffed active faults. In this study, three composite borehole profiles and a large-scale trench excavati...Composite borehole profiling combined with trenching is an effective way to acquire evidence of past ruptures of buffed active faults. In this study, three composite borehole profiles and a large-scale trench excavation were carded out across the surface rupture zone of the 1976 Ms7.8 Tangshan earthquake. The following three major conclusions have been reached. （1） The surface rupture zone of the 1976 earthquake extends more than 47 km long to the south of Tangshan city, passing to the west of Sunjialou, to Daodi town in Fengnan County, to Xihe in Fengnan County. （2） The surface rupture zone is divided into south and north branches. The north branch has mainly fight-lateral strike-slip motion, and the vertical displacement of the surface is up on the west and down on the east. On the other hand, the vertical displacement of the south branch is up on the east and down on the west, accompanied by some right-lateral slip. Such a faulting style cannot be explained by the movement of a single normal or reverse fault, but is consistent with the vertical displacement field induced by the fight-lateral strike-slip of the fault belt. The drilling and trenching data from this study verify that such activity continued through the Late Quaternary on the Tangshan Fault. （3） The fault planes exhumed by trenching and the dislocations of strata revealed by the boreholes indicate that multiple faulting events occurred on the Tangshan Fault in the Late Quaternary. The timing of three ruptures prior to the 1976 earthquake was 7.61-8.13, 〉14.57, and 24.21-26.57 ka BP. Counting the earthquake of 1976, the recurrence interval of the four strong events is about 6.7 to 10.8 ka. On one of the three borehole profiles, the Niumaku profile, nine faulting events were detected since 75.18 ka BP with an average interval of 8.4 ka. In addition, this paper also discusses the difference between the Late Quaternary sedimentary environments to the north and south of Tangshan city based on stratum dating.展开更多
文摘Surface notches lower the stiffness of laminated strips, so they lower the buckling loads of the laminated strips, too. In this paper a new method is proposed to predict the buckling loads of the laminated strips with a surface notch. The theoretical and experimental results show that the buckling loads decrease as the depth or width of the surface notches increase; when the stacking sequence of the laminated strips is [0°/0°/+ θ/-θ/0°/0°/+θ/-θ] s , the buckling load decrease as θ increases. It proves that the method is reliable and significant.
基金Supported by the National High Technology Research and Development Program of China （2007AA030303）, the National Basic Research Program of China （2009CB623400） and the National Natural Science Foundation of China （20776067）.
文摘Ceramic capillary membrane has received much attention due to its relatively high pack density and favorable mechanical strength.However,it is difficult to prepare capillary membrane on its thin support by a dip-coating method.In this study,alumina microfiltration membranes were prepared on the inner surface of alumina capillary support(outer diameter 4 mm,inner diameter 2.5 mm)by a dip-coating method.Scanning electron microscopy(SEM)observation,gas bubble pressure(GBP)method and membrane permeation test were carried out to evaluate membrane performance.Two major effects in preparation of crack-free membrane,capillary filtration and film-coating,upon the thin support were studied.The as-prepared crack-free membrane presents a narrow pore size distribution,a mean pore size of about 0.6μm and a high pure water flux of 86000 L·m -2 ·h -1 ·MPa.It is proved that the membrane thickness should be sufficiently large to overcome the defects of support surface,but it is only one of the prerequisites for the formation of crack-free membrane.Furthermore,it is demonstrated that the capillary filtration effect is greatly restricted for thin capillary support with the dip-coating method and the film-coating effect plays a crucial role in the formation of crack-free membrane.
基金provided by the National Natural Science Foundation of China (No. 51304202)the Natural Science Foundation of Jiangsu Province of China (No. BK20130190)+1 种基金the Fundamental Research Funds for the Central Universities (No. 2013QNA28)the Priority Academic Program Development of Jiangsu Higher Education Institutions (No. SZBF2011-6-B35)
文摘Aiming at the shallow depth seam proximity beneath a room mining goaf, due to that the shallow depth seam is exploited using the longwall mining and overlain by thin bedrock and thick loose sands, many accidents are likely to occur, including roof structure instability, roof step subsidence, damages of shield supports, and the face bumps triggered by the large area roof weighting, resulting in serious threats to the safety of underground miners and equipment. This paper analyses the overlying strata movement rules for the shallow seams using the physical simulation, the 3DEC numerical simulation and the field mea- surements. The results show that, in shallow seam mining, the overburden movement forms caved zone and fractured zone, the cracks develop continuously and reach the surface with the face advancing, and the development of surface cracks generally goes through four stages. With the application of loose blast- ing of residual pillars, reasonable mining height, and roof support and management, the safe, efficient and high recovery rate mining has been achieved in the shallow depth seam proximity beneath a room min ing goal.
基金Project(2013CB035700) supported by the National Basic Research Program of ChinaProjects(11272259,11321062,11002104) supported by the National Natural Science Foundation of China
文摘Multiple surface cracks and interfacial delamination are the major failure mechanisms in film/substrate systems.The effect of interlayer upon the failure mechanisms of interfacial delamination concomitant to surface crack was explored.Finite element model was developed to obtain the stress and energy release rate(ERR),which governs the propagation of interface cracks.The dependences of delamination upon the geometry and constitutive properties of interlayer were examined.The results indicate that the effect of elastic modulus of interlayer on the steady state ERR is insignificant.In cases of different geometrical parameters,however,the steady ERR decreases with the increase of the interlayer thickness.These findings lead to the conclusion that the interlayer constraint has significant effect on the ERR and thus coating life,which can be adopted to modify the ceramic top coat.
文摘In the present work, uranium concentrations were measured in twenty surface soil samples forselected regions in AI-Anbargovernorate using fission track etch technique, CR-39 track detector was used for registration of induced fission tracks. The results show that, the uranium concentrations ranged from 4.61 ppm, 56.93 Bq/kg （AL-Falluja AL-Jolan District） to 1.81 ppm 22.35 Bq/kg （Anah）with an average 3.42±0.79 ppm, 41.76±9.04 Bq/kg. The present results have shown that the uranium concentrations in the studied surface soil samples were less than the allowed limit 11.7 ppm recommended by UNSCEAR, 1993.
基金supported by the National Basic Research Program(973 program) of China(Grant No.2008CB425701)
文摘Madoi-Gade fault is an active fault in the Bayan Har block. According to field investigation, there is an earthquake surface rupture fairly well preserved on the Gade segment of the Madoi-Gade fault zone. The length of the rupture is approximately 50km, with a general strike of NW. The maximum horizontal sinistral displacement is about 7.6m and the maximum vertical displacement is about 4m. A large number of earthquake traces are to be found along the rupture zone, and the phenomena on the surface rupture are also various. Field investigation and analysis on the geological and geomorphological phenomena show that the formation age of the surface rupture is relatively young. A series of linear arranged, triangular facets, fault scarps, fault springs, dislocated gullies, twisted mountain ridges, sag-ponds, dislocated ridges, etc. exist along the fault. Based on the analysis of field investigation and the data available, we believe that the surface rupture is due to a strong earthquake in the history of this area. And it is inferred that the Madoi- Gade fault within the Bayan Har block has been highly active since Late Quaternary and may still be active nowadays.
基金sponsored by the Special Earthquake Research Program(20070851)National Key Basic Research Development Planning grogram(2004CB418401)+1 种基金Basic Science Research Professional of Institute of Crustal Dynamics (2008)National Science and Technology Support Program(2006BAC13B01 -0202),China
文摘The M8.0 Wenchuan earthquake occurred on the Longmenshan fault zone. Based on field investigation of the surface rupture and focal mechanism study of the aftershocks, we discuss the geological relationship of the main, secondary and triggered ruptures. The main rupture is about 200km long and can be divided into the south part and the north part. The south part consists of two parallel fault zones characterized by reverse faulting, with several parallel secondary ruptures on the hanging wall of the main fault, and the north part is a single main fault zone characterized by lateral strike-slip and reverse faulting. Compared to a 300km long aftershock distribution, the surface rupture only occupies 200km, and the remaining lOOkm on the northeast of the main rupture was triggered by aftershocks. Study on the ruptures of this earthquake will be useful for studying the earthquake risk evolution on the Longmenshan fault system.
基金supported by the Fundamental Research Funds of Institute of Crustal Dynamics,China Earthquake Adminishtration (Grant No. ZDJ2007-1)
文摘Composite borehole profiling combined with trenching is an effective way to acquire evidence of past ruptures of buffed active faults. In this study, three composite borehole profiles and a large-scale trench excavation were carded out across the surface rupture zone of the 1976 Ms7.8 Tangshan earthquake. The following three major conclusions have been reached. （1） The surface rupture zone of the 1976 earthquake extends more than 47 km long to the south of Tangshan city, passing to the west of Sunjialou, to Daodi town in Fengnan County, to Xihe in Fengnan County. （2） The surface rupture zone is divided into south and north branches. The north branch has mainly fight-lateral strike-slip motion, and the vertical displacement of the surface is up on the west and down on the east. On the other hand, the vertical displacement of the south branch is up on the east and down on the west, accompanied by some right-lateral slip. Such a faulting style cannot be explained by the movement of a single normal or reverse fault, but is consistent with the vertical displacement field induced by the fight-lateral strike-slip of the fault belt. The drilling and trenching data from this study verify that such activity continued through the Late Quaternary on the Tangshan Fault. （3） The fault planes exhumed by trenching and the dislocations of strata revealed by the boreholes indicate that multiple faulting events occurred on the Tangshan Fault in the Late Quaternary. The timing of three ruptures prior to the 1976 earthquake was 7.61-8.13, 〉14.57, and 24.21-26.57 ka BP. Counting the earthquake of 1976, the recurrence interval of the four strong events is about 6.7 to 10.8 ka. On one of the three borehole profiles, the Niumaku profile, nine faulting events were detected since 75.18 ka BP with an average interval of 8.4 ka. In addition, this paper also discusses the difference between the Late Quaternary sedimentary environments to the north and south of Tangshan city based on stratum dating.
