以贵州某公司扩建技改工程横三路隧道为依托,建立三维有限元动力模型,根据公安部门设定15 kg TNT炸药的要求,研究爆炸冲击荷载作用下二次衬砌结构变形特性、力学响应及能量分布。研究表明迎爆侧隧道结构出现能量集聚现象,大部分衬砌结...以贵州某公司扩建技改工程横三路隧道为依托,建立三维有限元动力模型,根据公安部门设定15 kg TNT炸药的要求,研究爆炸冲击荷载作用下二次衬砌结构变形特性、力学响应及能量分布。研究表明迎爆侧隧道结构出现能量集聚现象,大部分衬砌结构振动速度大于爆破安全规程的允许标准;爆炸所在的隧道衬砌结构局部破坏,但不会大面积坍塌。爆炸区域隧道衬砌以剪切破坏控制为主,附近衬砌结构发生受拉破坏。炸药冲击荷载对相邻隧道影响相对较小,结构发生开裂,不会造成瞬间垮塌失稳现象。展开更多
Comparative analysis between the quantitative data of active faults and seismicity reveals that a complete earthquake recurrence cycle includes the characteristic earthquake and the sub-maxima earthquakes in-between. ...Comparative analysis between the quantitative data of active faults and seismicity reveals that a complete earthquake recurrence cycle includes the characteristic earthquake and the sub-maxima earthquakes in-between. The magnitude of the sub-maxima events is correlated with the elapsed time of the characteristic earthquake and the slip rate of the fault. The fault displacement includes the major stick-slip generated by the characteristic earthquakes and the minor stick-slip by the sub-maxima ones. The magnitude-frequency relationship still works in the complete recurrence cycle. The energy accumulation in the cycle is divided approximately into four phases, and the seismicity differs at each phase. The relation of the maximum displacement with the average displacement of the characteristic earthquake suggests the partitioning of deformation between the characteristic and the sub-maxima earthquakes. Based on the above analysis, relevant mathematical equations are put forward for the quantitative assessment of the potential magnitude and earthquake risk of seismogenic tectonics. Tentative study has been carried out in this aspect in some areas of Tianshan.展开更多
The study on the enterprise＇s energy efficiency is one of the most important fields of energy efficiency research. Most studies used DEA and aggregate data to estimate the energy efficiency of enterprises. In this st...The study on the enterprise＇s energy efficiency is one of the most important fields of energy efficiency research. Most studies used DEA and aggregate data to estimate the energy efficiency of enterprises. In this study, based on Cobb-Douglas production function, we make a SFA model which takes the energy input and CO2 emission into account. By using the SFA model, we calculate the refineries＇ total-factor energy efficiency with Sinopec refineries＇ micro-data from 2004 to 2009. Meanwhile, we do empirical study on the factors which influence the energy efficiency. In the last, we put forward some advices so as to improve energy efficiency.展开更多
The mechanical properties of recycled aggregates concrete from demolition have been studied for several years. It has been documented that rheological properties of these concrete are generally affected by use of recy...The mechanical properties of recycled aggregates concrete from demolition have been studied for several years. It has been documented that rheological properties of these concrete are generally affected by use of recycled aggregates. They could present mechanical properties less affected by the presence of recycled aggregates if the initial concrete were of good quality. However, manufacturing problems, mainly attributed to the angular character of these aggregates and to the granulometry of recycled sand, limit their industrial use. The worth point of this study consists in the optimization of the concrete formulation using specific admixture, adapted to this aggregates in order to facilitate its manufacturing. It shows that the new generation of superplasticizers containing some copolymer polycarboxylate makes it possible to significantly improve the fluidity of the recycled aggregates concrete in its fresh state. The aim of this research is to control rheologica] properties of fresh recycled aggregates concrete with fine and coarse recycled aggregates to limit the negative influence of aggregates on mechanical properties of concrete.展开更多
ZnO hierarchical aggregates have been successfully synthesized by solvothermal methods through reaction of zinc acetate and potassium hydroxide in methanol solution. The shapes of the aggregates were controlled by var...ZnO hierarchical aggregates have been successfully synthesized by solvothermal methods through reaction of zinc acetate and potassium hydroxide in methanol solution. The shapes of the aggregates were controlled by varying the ratio of Zn2~ and OH- ions in the reaction system, while the size can be tuned from 2μm to 100 nm. Oriented attachment was found to be the main mechanism of the three-dimensional assembly of small ZnO nanocrystallites into large aggregates. The performance of these aggregates in dye-sensitized solar cells （DSCs） indicated that hierarchical structured photoelectrodes can increase energy conversion efficiency of DSCs effectively when the sizes of aggregates match the wavelengths of visible light.展开更多
The author reviews some recent developments in Chern-Simons theory on a hyperbolic 3-manifold M with complex gauge group G. The author focuses on the case of G = SL(N, C) and M being a knot complement: M = S^3\ K. The...The author reviews some recent developments in Chern-Simons theory on a hyperbolic 3-manifold M with complex gauge group G. The author focuses on the case of G = SL(N, C) and M being a knot complement: M = S^3\ K. The main result presented in this note is the cluster partition function, a computational tool that uses cluster algebra techniques to evaluate the Chern-Simons path integral for G = SL(N, C). He also reviews various applications and open questions regarding the cluster partition function and some of its relation with string theory.展开更多
文摘以贵州某公司扩建技改工程横三路隧道为依托,建立三维有限元动力模型,根据公安部门设定15 kg TNT炸药的要求,研究爆炸冲击荷载作用下二次衬砌结构变形特性、力学响应及能量分布。研究表明迎爆侧隧道结构出现能量集聚现象,大部分衬砌结构振动速度大于爆破安全规程的允许标准;爆炸所在的隧道衬砌结构局部破坏,但不会大面积坍塌。爆炸区域隧道衬砌以剪切破坏控制为主,附近衬砌结构发生受拉破坏。炸药冲击荷载对相邻隧道影响相对较小,结构发生开裂,不会造成瞬间垮塌失稳现象。
文摘Comparative analysis between the quantitative data of active faults and seismicity reveals that a complete earthquake recurrence cycle includes the characteristic earthquake and the sub-maxima earthquakes in-between. The magnitude of the sub-maxima events is correlated with the elapsed time of the characteristic earthquake and the slip rate of the fault. The fault displacement includes the major stick-slip generated by the characteristic earthquakes and the minor stick-slip by the sub-maxima ones. The magnitude-frequency relationship still works in the complete recurrence cycle. The energy accumulation in the cycle is divided approximately into four phases, and the seismicity differs at each phase. The relation of the maximum displacement with the average displacement of the characteristic earthquake suggests the partitioning of deformation between the characteristic and the sub-maxima earthquakes. Based on the above analysis, relevant mathematical equations are put forward for the quantitative assessment of the potential magnitude and earthquake risk of seismogenic tectonics. Tentative study has been carried out in this aspect in some areas of Tianshan.
文摘The study on the enterprise＇s energy efficiency is one of the most important fields of energy efficiency research. Most studies used DEA and aggregate data to estimate the energy efficiency of enterprises. In this study, based on Cobb-Douglas production function, we make a SFA model which takes the energy input and CO2 emission into account. By using the SFA model, we calculate the refineries＇ total-factor energy efficiency with Sinopec refineries＇ micro-data from 2004 to 2009. Meanwhile, we do empirical study on the factors which influence the energy efficiency. In the last, we put forward some advices so as to improve energy efficiency.
文摘The mechanical properties of recycled aggregates concrete from demolition have been studied for several years. It has been documented that rheological properties of these concrete are generally affected by use of recycled aggregates. They could present mechanical properties less affected by the presence of recycled aggregates if the initial concrete were of good quality. However, manufacturing problems, mainly attributed to the angular character of these aggregates and to the granulometry of recycled sand, limit their industrial use. The worth point of this study consists in the optimization of the concrete formulation using specific admixture, adapted to this aggregates in order to facilitate its manufacturing. It shows that the new generation of superplasticizers containing some copolymer polycarboxylate makes it possible to significantly improve the fluidity of the recycled aggregates concrete in its fresh state. The aim of this research is to control rheologica] properties of fresh recycled aggregates concrete with fine and coarse recycled aggregates to limit the negative influence of aggregates on mechanical properties of concrete.
文摘ZnO hierarchical aggregates have been successfully synthesized by solvothermal methods through reaction of zinc acetate and potassium hydroxide in methanol solution. The shapes of the aggregates were controlled by varying the ratio of Zn2~ and OH- ions in the reaction system, while the size can be tuned from 2μm to 100 nm. Oriented attachment was found to be the main mechanism of the three-dimensional assembly of small ZnO nanocrystallites into large aggregates. The performance of these aggregates in dye-sensitized solar cells （DSCs） indicated that hierarchical structured photoelectrodes can increase energy conversion efficiency of DSCs effectively when the sizes of aggregates match the wavelengths of visible light.
基金supported by the U.S.Department of Energy(No.DE-SC0009988)
文摘The author reviews some recent developments in Chern-Simons theory on a hyperbolic 3-manifold M with complex gauge group G. The author focuses on the case of G = SL(N, C) and M being a knot complement: M = S^3\ K. The main result presented in this note is the cluster partition function, a computational tool that uses cluster algebra techniques to evaluate the Chern-Simons path integral for G = SL(N, C). He also reviews various applications and open questions regarding the cluster partition function and some of its relation with string theory.
