The Federal Highway Administration (FHWA) sponsored a large,multi-year project conducted by the Multidisciplinary Center for Earthquake Engineering Research (MCEER) titled'Seismic Vulnerability of New Highway Cons...The Federal Highway Administration (FHWA) sponsored a large,multi-year project conducted by the Multidisciplinary Center for Earthquake Engineering Research (MCEER) titled'Seismic Vulnerability of New Highway Construction'(MCEER Project 112),which was completed in 1998.MCEER coordinated the work of many researchers,who performed studies on the seismic design and vulnerability analysis of highway bridges,tunnels,and retaining structures. Extensive research was conducted to provide revisions and improvements to current design and detailing approaches and national design specifications for highway bridges.The program included both analytical and experimental studies,and addressed seismic hazard exposure and ground motion input for the U.S.highway system;foundation design and soil behavior: structural importance,analysis,and response:structural design issues and details;and structural design criteria.展开更多
Binary piezoelectric crystal Pb(Mg_(1/3)Nb_(2/3))O_(3)–PbTiO_(3)(PMN–PT)has excellent dielectric and piezoelectric properties,which has led to the commercialization for medical ultrasound imaging.Recently,there is a...Binary piezoelectric crystal Pb(Mg_(1/3)Nb_(2/3))O_(3)–PbTiO_(3)(PMN–PT)has excellent dielectric and piezoelectric properties,which has led to the commercialization for medical ultrasound imaging.Recently,there is a growing demand for piezoelectric crystals with improved thermal and electrical properties.Ternary piezoelectric crystals Pb(In_(1/2)Nb_(1/2))O_(3)–Pb(Mg_(1/3)Nb_(2/3))O_(3)–PbTiO_(3)(PIN–PMN–PT)have increased depoling temperature and coercive field than binary PMN–PT.To better understand the ternary crystal system and improve crystal properties,we systematically investigated crystal growth of PIN–PMN–PT with modified Bridgman method.Like PMN–PT,PIN–PMN–PT crystals have excellent piezoelectric properties(e.g.,k_(33)0:87–0.92,d_(33)1000–2200 pm/V).Higher PIN content leads to40C increase in depoling temperature and more than doubling of coercive field(7.0 kV/cm).Such improvements are advantageous for applications where high temperature and/or high-drive are needed.展开更多
基金the Federal Highway Administration under contract number DTFH61-92-C-00112.
文摘The Federal Highway Administration (FHWA) sponsored a large,multi-year project conducted by the Multidisciplinary Center for Earthquake Engineering Research (MCEER) titled'Seismic Vulnerability of New Highway Construction'(MCEER Project 112),which was completed in 1998.MCEER coordinated the work of many researchers,who performed studies on the seismic design and vulnerability analysis of highway bridges,tunnels,and retaining structures. Extensive research was conducted to provide revisions and improvements to current design and detailing approaches and national design specifications for highway bridges.The program included both analytical and experimental studies,and addressed seismic hazard exposure and ground motion input for the U.S.highway system;foundation design and soil behavior: structural importance,analysis,and response:structural design issues and details;and structural design criteria.
基金supported by ONR contracts N00014-C and N00014-M,and HC-R&D fund-2001-13.
文摘Binary piezoelectric crystal Pb(Mg_(1/3)Nb_(2/3))O_(3)–PbTiO_(3)(PMN–PT)has excellent dielectric and piezoelectric properties,which has led to the commercialization for medical ultrasound imaging.Recently,there is a growing demand for piezoelectric crystals with improved thermal and electrical properties.Ternary piezoelectric crystals Pb(In_(1/2)Nb_(1/2))O_(3)–Pb(Mg_(1/3)Nb_(2/3))O_(3)–PbTiO_(3)(PIN–PMN–PT)have increased depoling temperature and coercive field than binary PMN–PT.To better understand the ternary crystal system and improve crystal properties,we systematically investigated crystal growth of PIN–PMN–PT with modified Bridgman method.Like PMN–PT,PIN–PMN–PT crystals have excellent piezoelectric properties(e.g.,k_(33)0:87–0.92,d_(33)1000–2200 pm/V).Higher PIN content leads to40C increase in depoling temperature and more than doubling of coercive field(7.0 kV/cm).Such improvements are advantageous for applications where high temperature and/or high-drive are needed.
