To develop a high performance buckling-restrained brace （BRB） with less weight, an innovative type of the BRB with transverse rib restraints is proposed and studied through experiment. Three BRB specimens are cyclic...To develop a high performance buckling-restrained brace （BRB） with less weight, an innovative type of the BRB with transverse rib restraints is proposed and studied through experiment. Three BRB specimens are cyclically loaded in the investigation. Specimen 1 adopts a Q235 core member and transverse rib restraints. Specimen 2 adopts a LYP160 low yield point steel core member and transverse rib restraints. Specimen 3 adopts a LYP160 low yield point steel core member and mortar restraint. The experimental results indicate that the transverse rib restraining mode can provide sufficient lateral stiffness for the core member and effectively restrain its buckling. The BRB specimens with a LYP160 core member exhibit better hysteretic performance and energy dissipation capacity than the specimens with a Q235 core member.展开更多
We present a 1 × 4 Y-branch digital optical switch in which S-bend variable optical attenuators are integrated. The S-bend waveguides, which are always introduced to connect the switch and the standard fiber arra...We present a 1 × 4 Y-branch digital optical switch in which S-bend variable optical attenuators are integrated. The S-bend waveguides, which are always introduced to connect the switch and the standard fiber array, are made use of and designed as variable optical attenuators. A compact device with low crosstalk and larger branching-angle is obtained. The device is fabricated on the thermo-optic polymer materials,and the performance of the device is measured. With an applied driving power of less than 200mW, the device has a low crosstalk of less than - 35dB at a wavelength of 1.55 μm.展开更多
The feedrate profile of non-uniform rational B-spline （NURBS） interpolation due to the contour errors is analyzed. A NURBS curve interpolator with adaptive acceleration-deceleration control is presented. In interpo-...The feedrate profile of non-uniform rational B-spline （NURBS） interpolation due to the contour errors is analyzed. A NURBS curve interpolator with adaptive acceleration-deceleration control is presented. In interpo- lation preprocessing, the sensitive zones of feedrate variations are processed with acceleration-deceleration control. By using the proposed algorithm, the machining accuracy is guaranteed and the feedrate is adaptively adjusted to he smoothed. The mechanical shock imposed in the servo system is avoided by the first and the second time derivatives of feedrates. A simulation of NURBS interpolation is given to demonstrate the validity and the effectiveness of the algorithm. The proposed interpolator can also be applied to the trajectory planning of the other parametric curves.展开更多
Research into the characteristics of geothermal fields is important for the control of heat damage in mines. Based on measured geothermal data of boreholes from 200 m to 1200 m in a Jiahe Coal Mine, we demonstrate non...Research into the characteristics of geothermal fields is important for the control of heat damage in mines. Based on measured geothermal data of boreholes from 200 m to 1200 m in a Jiahe Coal Mine, we demonstrate non-linear but increasing relations of both geo-temperatures and geothermal gradients with increases depth. Numerically, we fitted the relationship between geo-temperatures and depth, a first-order exponential decay curve, formulated as: T(h) = 4.975 + 23.08 exp(h/1736.1).展开更多
The core of strength reduction method(SRM) involves finding a critical strength curve that happens to make the slope globally fail and a definition of factor of safety(FOS). A new double reduction method, including a ...The core of strength reduction method(SRM) involves finding a critical strength curve that happens to make the slope globally fail and a definition of factor of safety(FOS). A new double reduction method, including a detailed calculation procedure and a definition of FOS for slope stability was developed based on the understanding of SRM. When constructing the new definition of FOS, efforts were made to make sure that it has concise physical meanings and fully reflects the shear strength of the slope. Two examples, slopes A and B with the slope angles of 63° and 34° respectively, were given to verify the method presented. It is found that, for these two slopes, the FOSs from original strength reduction method are respectively 1.5% and 38% higher than those from double reduction method. It is also found that the double reduction method predicts a deeper potential slide line and a larger slide mass. These results show that on one hand, the double reduction method is comparative to the traditional methods and is reasonable, and on the other hand, the original strength reduction method may overestimate the safety of a slope. The method presented is advised to be considered as an additional option in the practical slope stability evaluations although more useful experience is required.展开更多
The seismic hazard value is a fundamental quantity for the seismic risk assessment and for the determination of terms of references of seismic design of important facilities as dams, chemical plants, nuclear power pla...The seismic hazard value is a fundamental quantity for the seismic risk assessment and for the determination of terms of references of seismic design of important facilities as dams, chemical plants, nuclear power plants, etc.. In real sites, the seismic hazard value is influenced by both, the earthquake sizes, the impacts of which in a given site may be expected, and the properties of geological structure through which seismic waves spread from earthquake loci to a given site. The seismic risk is predetermined by hazard value, distribution of assets in the given site and asset numbers and vulnerabilities. The paper describes the used procedure of hazard assessment of important sites. The attention is especially paid to the basic steps as the data collection （homogeneity level, uncertainty and vagueness）, the focal region boundaries （their uncertainties and vagueness）, and the maximum expected earthquake size in each focal region that must be taken into account （its uncertainty and vagueness）, because they substantially influence the hazard value. Discussion is also concentrated to the attenuation that Central Europe substantially depends on the azimuth between earthquake focus and the given site. The attenuation differences are shown in seismic scenarios for individual focal regions. They are caused by focal mechanisms in near focal zone and differences in structure properties in distant zone; the boundary between near and distant zone in Central Europe is ca 2.5 h, where h is the focal depth in km. The real results are given for a real locality in Central Europe. It is shown than that great influence on hazard value is caused by great differences in azimuth attenuation curves. It is the reality that the Bohemian Massif is characterised with very low seismic attenuation in comparison with its vicinity. The following real results are presented： geological structure of near site vicinity, earthquake catalogue for Central Europe, focal regions in Central Europe, attenuation curves in Central Europe, typical earthquake isoseismals for individual focal regions, frequency graph, recurrence probability curve, etc.. The approaches used for nuclear facilities were recommended by the IAEA （International Atomic Energy Agency）.展开更多
Using a 1.5-layer reduced-gravity nonlinear shallow-water equation model, we studied the effect of the meridional wind on the western boundary currents (WBC) at critical states with hysteresis courses. The results of ...Using a 1.5-layer reduced-gravity nonlinear shallow-water equation model, we studied the effect of the meridional wind on the western boundary currents (WBC) at critical states with hysteresis courses. The results of the simulation indicate that the WBC is prone to penetrating into the gap under northerly winds, and its path is more difficult to alter due to the larger interval between the two critical transition curves (C1P and C1L). For southerly winds, the WBC is prone to leaping across the gap, and its path is easier to alter due to the smaller interval between the two critical transition curves. The simulation results also indicate that the meridional winds over the southern region of the gap are the dominant factor determining the formation of the WBC. The dynamic mechanism influencing the transport of WBC near the gap is both Ekman transport and the blocking of Ekman transport. Ekman transport induced by northerly winds may reduce the transport of the WBC, causing the β-effect to dominate the meridional advection (promoting the penetration). Southerly winds, however, may enhance the transport of the WBC, causing the meridional advection to dominate the β-effect (promoting the leaping state). These results explain some structural features of the Kuroshio at the Luzon Strait.展开更多
This paper analyzes the principle of spline interpolation, pointed out the reasons for the feed rate fluctuations and proposed interpolation algorithm based on the secant iteration method NURBS curve. The algorithm of...This paper analyzes the principle of spline interpolation, pointed out the reasons for the feed rate fluctuations and proposed interpolation algorithm based on the secant iteration method NURBS curve. The algorithm of the speed the planning section uses cubic polynomial acceleration and deceleration control methods to ensure the acceleration of the process of continuous high-speed operation, so that the machine runs smoothly, avoiding the machine have a big impact; while parameter calculation part using the Secant iterative interpolation method to calculate parameter, reducing the speed fluctuation, the machine is further reduced tremor. Simulation results show that the algorithm can obtain a continuous velocity and acceleration curves, and can be controlled in real time interpolation velocity fluctuations in the ideal range, the machine achieve the smooth running ,and meet the high-speed, high quality processing requirements.展开更多
基金The National Key Technology R&D Program of China during the12th Five-Year Plan Period(No.2012BAJ13B01)the Science and Technology Program of the Ministry of Housing and UrbanRural Development(No.2011-K2-3)+1 种基金the Science and Technology Foundation of Southeast University(No.9205000034)the Priority Academic Program Development of Jiangsu Higher Education Institutions(No.CE01-2-09)
文摘To develop a high performance buckling-restrained brace （BRB） with less weight, an innovative type of the BRB with transverse rib restraints is proposed and studied through experiment. Three BRB specimens are cyclically loaded in the investigation. Specimen 1 adopts a Q235 core member and transverse rib restraints. Specimen 2 adopts a LYP160 low yield point steel core member and transverse rib restraints. Specimen 3 adopts a LYP160 low yield point steel core member and mortar restraint. The experimental results indicate that the transverse rib restraining mode can provide sufficient lateral stiffness for the core member and effectively restrain its buckling. The BRB specimens with a LYP160 core member exhibit better hysteretic performance and energy dissipation capacity than the specimens with a Q235 core member.
文摘We present a 1 × 4 Y-branch digital optical switch in which S-bend variable optical attenuators are integrated. The S-bend waveguides, which are always introduced to connect the switch and the standard fiber array, are made use of and designed as variable optical attenuators. A compact device with low crosstalk and larger branching-angle is obtained. The device is fabricated on the thermo-optic polymer materials,and the performance of the device is measured. With an applied driving power of less than 200mW, the device has a low crosstalk of less than - 35dB at a wavelength of 1.55 μm.
基金Supported by the Natural Science Foundation of Jiangsu Province(BK2003005)~~
文摘The feedrate profile of non-uniform rational B-spline （NURBS） interpolation due to the contour errors is analyzed. A NURBS curve interpolator with adaptive acceleration-deceleration control is presented. In interpo- lation preprocessing, the sensitive zones of feedrate variations are processed with acceleration-deceleration control. By using the proposed algorithm, the machining accuracy is guaranteed and the feedrate is adaptively adjusted to he smoothed. The mechanical shock imposed in the servo system is avoided by the first and the second time derivatives of feedrates. A simulation of NURBS interpolation is given to demonstrate the validity and the effectiveness of the algorithm. The proposed interpolator can also be applied to the trajectory planning of the other parametric curves.
基金Financial support for this project,provided by the National Basic Research Program of China (No.2006CB202200)the Key Project of National Natural Science Foundation of China+1 种基金the Program for Changjiang Scholars,Innovative Research Team in University of China (No.IRT0656)the Fundamental Research Funds for the Central Universities (No.2010QL04)
文摘Research into the characteristics of geothermal fields is important for the control of heat damage in mines. Based on measured geothermal data of boreholes from 200 m to 1200 m in a Jiahe Coal Mine, we demonstrate non-linear but increasing relations of both geo-temperatures and geothermal gradients with increases depth. Numerically, we fitted the relationship between geo-temperatures and depth, a first-order exponential decay curve, formulated as: T(h) = 4.975 + 23.08 exp(h/1736.1).
基金Project(11102218) supported by the National Natural Science Foundation of China
文摘The core of strength reduction method(SRM) involves finding a critical strength curve that happens to make the slope globally fail and a definition of factor of safety(FOS). A new double reduction method, including a detailed calculation procedure and a definition of FOS for slope stability was developed based on the understanding of SRM. When constructing the new definition of FOS, efforts were made to make sure that it has concise physical meanings and fully reflects the shear strength of the slope. Two examples, slopes A and B with the slope angles of 63° and 34° respectively, were given to verify the method presented. It is found that, for these two slopes, the FOSs from original strength reduction method are respectively 1.5% and 38% higher than those from double reduction method. It is also found that the double reduction method predicts a deeper potential slide line and a larger slide mass. These results show that on one hand, the double reduction method is comparative to the traditional methods and is reasonable, and on the other hand, the original strength reduction method may overestimate the safety of a slope. The method presented is advised to be considered as an additional option in the practical slope stability evaluations although more useful experience is required.
文摘The seismic hazard value is a fundamental quantity for the seismic risk assessment and for the determination of terms of references of seismic design of important facilities as dams, chemical plants, nuclear power plants, etc.. In real sites, the seismic hazard value is influenced by both, the earthquake sizes, the impacts of which in a given site may be expected, and the properties of geological structure through which seismic waves spread from earthquake loci to a given site. The seismic risk is predetermined by hazard value, distribution of assets in the given site and asset numbers and vulnerabilities. The paper describes the used procedure of hazard assessment of important sites. The attention is especially paid to the basic steps as the data collection （homogeneity level, uncertainty and vagueness）, the focal region boundaries （their uncertainties and vagueness）, and the maximum expected earthquake size in each focal region that must be taken into account （its uncertainty and vagueness）, because they substantially influence the hazard value. Discussion is also concentrated to the attenuation that Central Europe substantially depends on the azimuth between earthquake focus and the given site. The attenuation differences are shown in seismic scenarios for individual focal regions. They are caused by focal mechanisms in near focal zone and differences in structure properties in distant zone; the boundary between near and distant zone in Central Europe is ca 2.5 h, where h is the focal depth in km. The real results are given for a real locality in Central Europe. It is shown than that great influence on hazard value is caused by great differences in azimuth attenuation curves. It is the reality that the Bohemian Massif is characterised with very low seismic attenuation in comparison with its vicinity. The following real results are presented： geological structure of near site vicinity, earthquake catalogue for Central Europe, focal regions in Central Europe, attenuation curves in Central Europe, typical earthquake isoseismals for individual focal regions, frequency graph, recurrence probability curve, etc.. The approaches used for nuclear facilities were recommended by the IAEA （International Atomic Energy Agency）.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences (Nos. KZCX1-YW-12, KZCX2-YW-201)the National Natural Science Foundation of China (No. 90411013)+2 种基金the National Basic Research Program of China (973 Program, No. 2006CB403600)NSFC's Outstanding Youth Grant (No. 40888001)the 100-Talent Program of the CAS, and the Outstanding Youth Grant of Shandong Province
文摘Using a 1.5-layer reduced-gravity nonlinear shallow-water equation model, we studied the effect of the meridional wind on the western boundary currents (WBC) at critical states with hysteresis courses. The results of the simulation indicate that the WBC is prone to penetrating into the gap under northerly winds, and its path is more difficult to alter due to the larger interval between the two critical transition curves (C1P and C1L). For southerly winds, the WBC is prone to leaping across the gap, and its path is easier to alter due to the smaller interval between the two critical transition curves. The simulation results also indicate that the meridional winds over the southern region of the gap are the dominant factor determining the formation of the WBC. The dynamic mechanism influencing the transport of WBC near the gap is both Ekman transport and the blocking of Ekman transport. Ekman transport induced by northerly winds may reduce the transport of the WBC, causing the β-effect to dominate the meridional advection (promoting the penetration). Southerly winds, however, may enhance the transport of the WBC, causing the meridional advection to dominate the β-effect (promoting the leaping state). These results explain some structural features of the Kuroshio at the Luzon Strait.
文摘This paper analyzes the principle of spline interpolation, pointed out the reasons for the feed rate fluctuations and proposed interpolation algorithm based on the secant iteration method NURBS curve. The algorithm of the speed the planning section uses cubic polynomial acceleration and deceleration control methods to ensure the acceleration of the process of continuous high-speed operation, so that the machine runs smoothly, avoiding the machine have a big impact; while parameter calculation part using the Secant iterative interpolation method to calculate parameter, reducing the speed fluctuation, the machine is further reduced tremor. Simulation results show that the algorithm can obtain a continuous velocity and acceleration curves, and can be controlled in real time interpolation velocity fluctuations in the ideal range, the machine achieve the smooth running ,and meet the high-speed, high quality processing requirements.
