Recently, the high-tech industry has become a key industry for economic development in many countries. However, vibration sensitive equipment located in these industrial buildings is vulnerable during earthquakes, whi...Recently, the high-tech industry has become a key industry for economic development in many countries. However, vibration sensitive equipment located in these industrial buildings is vulnerable during earthquakes, which may cause huge economic loss. In this study, an innovative isolator for safeguarding the vibration sensitive equipment, namely, the static dynamics interchangeable^all pendulum system （SDI-BPS） is proposed and investigated to examine its protective capability for the vibration sensitive equipment during earthquakes through a series of tri-directional shaking table tests. The experimental results illustrate that the SDI-BPS isolator can provide significant damping to rolling types of base isolation systems for reducing the bearing displacement and size, and avoid the stress concentration, which can cause damage or scratches on the rolling surface of the isolator, to prolong its life span of service. The SDI-BPS isolator also provides excellent capability in protecting the vibration sensitive equipment and exhibits a stable behavior under long terms of service loadings and earthquakes.展开更多
Steel micro fibers provide strengthening,toughening and durability improve-ment mechanisms in cementitious composites.However,there is not much data in the literature regarding how the extent of their effectiveness ch...Steel micro fibers provide strengthening,toughening and durability improve-ment mechanisms in cementitious composites.However,there is not much data in the literature regarding how the extent of their effectiveness changes depend-ing on the type of matrix being reinforced.For clarifying this point,the influ-ence of a constant volumetric ratio(1%)of 6 mm long steel micro fibers on the performance of 5 mortar mixtures was investigated and were prepared using plain,binary and ternary cementitious systems.A total of 10 mixtures were cast.The mineral admixtures used in the study include silica fume(SF),metakaolin(MK)and a Class C fly ash(FA).While the replacement levels of SF and MK were 10%by weight of the total mass of the binder,this ratio was chosen as 30%for FA.In addition to the behavior of the mixtures under compressive,flexural and impact loads,abrasion,water absorption,chloride ion penetration,freez-ing-thawing resistance and drying shrinkage characteristics of the mixtures were determined.Test results indicate that generally the refinement in the pore struc-ture of the matrix provided by mineral admixtures and the increase in resistance against growth and coalescence of micro-cracks provided by fibers produce a syn-ergistic effect and improve the investigated performances of the mixtures.展开更多
In this study,zirconium(Zr) successfully substituted for erbium(Er) in Er_(6-x)Zr_(x)MnSb_(2)(x=0,0.5,1,1.5) of the Fe_(2)P type,with comprehensive characterizations on crystal structure,electronic structure and magne...In this study,zirconium(Zr) successfully substituted for erbium(Er) in Er_(6-x)Zr_(x)MnSb_(2)(x=0,0.5,1,1.5) of the Fe_(2)P type,with comprehensive characterizations on crystal structure,electronic structure and magnetic properties.According to synchrotron powder X-ray diffraction data analysis and density functional theory calculation,Zr does not randomly but preferentially occupy during the doping process and results in weaker magnetic exchange interactions and depressed ordering temperatures.The electronic structure data show that the doping of Zr can weaken interaction between Er and Mn atoms.Owing to multiple transitions,the Er_(6-x)Zr_(x)MnSb_(2)(x=0,0.5,1,1.5) exhibit table-like magnetocaloric effect.Er_(6)MnSb_(2) displays wide δT_(FWHM)(full width at half maximum of the magnetic entropy change curve) of 116 K and high relative cooling power of 388.62 J/kg for 3 T.The maximum magnetic entropy change of Er_(6-x)Zr_(x)MnSb_(2) is increased from 3.81 to 7.69 J/(kg·K) with the Zr content up from x=0 to x=1.5.展开更多
基金the Science Council in Taiwan for the financial support(Project No.NSC 95- 2221-E-035-1120)
文摘Recently, the high-tech industry has become a key industry for economic development in many countries. However, vibration sensitive equipment located in these industrial buildings is vulnerable during earthquakes, which may cause huge economic loss. In this study, an innovative isolator for safeguarding the vibration sensitive equipment, namely, the static dynamics interchangeable^all pendulum system （SDI-BPS） is proposed and investigated to examine its protective capability for the vibration sensitive equipment during earthquakes through a series of tri-directional shaking table tests. The experimental results illustrate that the SDI-BPS isolator can provide significant damping to rolling types of base isolation systems for reducing the bearing displacement and size, and avoid the stress concentration, which can cause damage or scratches on the rolling surface of the isolator, to prolong its life span of service. The SDI-BPS isolator also provides excellent capability in protecting the vibration sensitive equipment and exhibits a stable behavior under long terms of service loadings and earthquakes.
文摘Steel micro fibers provide strengthening,toughening and durability improve-ment mechanisms in cementitious composites.However,there is not much data in the literature regarding how the extent of their effectiveness changes depend-ing on the type of matrix being reinforced.For clarifying this point,the influ-ence of a constant volumetric ratio(1%)of 6 mm long steel micro fibers on the performance of 5 mortar mixtures was investigated and were prepared using plain,binary and ternary cementitious systems.A total of 10 mixtures were cast.The mineral admixtures used in the study include silica fume(SF),metakaolin(MK)and a Class C fly ash(FA).While the replacement levels of SF and MK were 10%by weight of the total mass of the binder,this ratio was chosen as 30%for FA.In addition to the behavior of the mixtures under compressive,flexural and impact loads,abrasion,water absorption,chloride ion penetration,freez-ing-thawing resistance and drying shrinkage characteristics of the mixtures were determined.Test results indicate that generally the refinement in the pore struc-ture of the matrix provided by mineral admixtures and the increase in resistance against growth and coalescence of micro-cracks provided by fibers produce a syn-ergistic effect and improve the investigated performances of the mixtures.
基金Project supported by the National Natural Science Foundation of China (51861003)the Research Grants Council of Hong Kong(17208120)。
文摘In this study,zirconium(Zr) successfully substituted for erbium(Er) in Er_(6-x)Zr_(x)MnSb_(2)(x=0,0.5,1,1.5) of the Fe_(2)P type,with comprehensive characterizations on crystal structure,electronic structure and magnetic properties.According to synchrotron powder X-ray diffraction data analysis and density functional theory calculation,Zr does not randomly but preferentially occupy during the doping process and results in weaker magnetic exchange interactions and depressed ordering temperatures.The electronic structure data show that the doping of Zr can weaken interaction between Er and Mn atoms.Owing to multiple transitions,the Er_(6-x)Zr_(x)MnSb_(2)(x=0,0.5,1,1.5) exhibit table-like magnetocaloric effect.Er_(6)MnSb_(2) displays wide δT_(FWHM)(full width at half maximum of the magnetic entropy change curve) of 116 K and high relative cooling power of 388.62 J/kg for 3 T.The maximum magnetic entropy change of Er_(6-x)Zr_(x)MnSb_(2) is increased from 3.81 to 7.69 J/(kg·K) with the Zr content up from x=0 to x=1.5.
