Drosophila dEAAT2, a member of the excitatory amino-acid transporter(EAAT) family, has been described as mediating the high-affinity transport of taurine, which is a free amino-acid abundant in both insects and mammal...Drosophila dEAAT2, a member of the excitatory amino-acid transporter(EAAT) family, has been described as mediating the high-affinity transport of taurine, which is a free amino-acid abundant in both insects and mammals. However, the role of taurine and its transporter in hearing is not clear. Here, we report that dEAAT2 is required for the larval startle response to sound stimuli. d EAAT2 was found to be enriched in the distal region of chordotonal neurons where sound transduction occurs. The Ca^(2+) imaging and electrophysiological results showed that disrupted dEAAT2 expression significantly reduced the response of chordotonal neurons to sound.More importantly, expressing d EAAT2 in the chordotonal neurons rescued these mutant phenotypes. Taken together,these findings indicate a critical role for Drosophila dEAAT2 in sound transduction by chordotonal neurons.展开更多
Semi-solid forging of iron-based alloys during solidification has unique characteristics distinct from those of the classical hot forging.With the aim of acquiring precise knowledge concerning the microstructural evol...Semi-solid forging of iron-based alloys during solidification has unique characteristics distinct from those of the classical hot forging.With the aim of acquiring precise knowledge concerning the microstructural evolution of bearing steel Cr4 Mo4 V in this process,a series of semi-solid forging experiments were carried out in which samples were wrapped in a designed pure iron sheath.The effects of forging temperature and forging reduction on the grain morphology and liquid flow behavior were investigated,respectively.By forging solidifying metal(FSM),bulky primary dendrites were broken and spheroidal grains with an average shape factor of 0.87 were obtained at 1360?C.With the decreasing forging temperature to 1340?C,the microstructural homogeneity can be improved.On the other hand,it shows that a higher forging reduction(50%)is essential for the spheroidization of grains and elimination of liquid segregation.Those microstructural characteristics are related to different motion mechanisms of solid and liquid phases at different forging temperatures.Additionally,the effect of semi-solid forging on the eutectic carbides was also investigated,and the results demonstrate that the higher diffusion capacity and less liquid segregation jointly lower the large eutectic carbides and consequently cause its uniform distribution during FSM.展开更多
Detailed three-dimensional(3 D)microtomography characterizations of inclusions in electrode matrix,mushy zone(MZ)and liquid melt film(LMF)were performed to elucidate the motion and removal behavior of inclusions in el...Detailed three-dimensional(3 D)microtomography characterizations of inclusions in electrode matrix,mushy zone(MZ)and liquid melt film(LMF)were performed to elucidate the motion and removal behavior of inclusions in electrode tip during magnetically controlled electroslag remelting(MC-ESR)process.A transient 2 D numerical model was also built to verify the experimental results and proposed mechanisms.The number and size of inclusions exhibited an obvious increasing trend from edge to mid region in LMF,while remained almost the same in electrode matrix and MZ.The inclusions in LMF migrated from edge to mid region of LMF,accompanied with removal process.In addition,the kinetic conditions for inclusion migrating to LMF/slag interface(LSI)were enhanced during MC-ESR process,thereby improving the inclusion removal efficiency in LMF.This work highlights the 3 D characterization and motion/removal mechanisms of inclusions in electrode tip,as well as sheds new light on preparing high purity materials.展开更多
Over recent years,eutectic high-entropy alloys(EHEAs)have intrigued substantial research enthusiasms due to their good castability as well as balanced strength-ductility synergy.In this study,a bulk cast Al_(19.25)Co_...Over recent years,eutectic high-entropy alloys(EHEAs)have intrigued substantial research enthusiasms due to their good castability as well as balanced strength-ductility synergy.In this study,a bulk cast Al_(19.25)Co_(18.86)Fe_(18.36)Ni_(43.53)EHEA is developed with fine in-situ lamellar eutectics.The eutectics comprise alternating ordered face-centered-cubic(L1_(2))and ordered body-centered-cubic(B2)phases with semicoherent interfaces.The resulting microstructure resembles that of most reported as-cast EHEAs,but the B2 lamellae are devoid of nano-precipitates because of the Cr-element removal in current tailored eutectic composition.Surprisingly,the B2 lamellae still feature much higher deformation resistance than the L1_(2) lamellae,so that less lattice defects are detected in the B2 lamellae until the fracture.More interestingly,in the L1_(2) lamellae we identify a dynamic microstructure refinement that correlates to extraordinary strain hardening in tension.The precipitate-free EHEA consequently shows excellent tensile ductility of~10%and high ultimate strength up to~956 MPa.展开更多
As a promising material for the new generation of high-speed railway contact wires,the comprehensive optimization of the electrical conductivity,strength,hardness and wear resistance of the Cu-Cr-Zr alloy has received...As a promising material for the new generation of high-speed railway contact wires,the comprehensive optimization of the electrical conductivity,strength,hardness and wear resistance of the Cu-Cr-Zr alloy has received extensive attention.In this paper,a high-performance Cu-1Cr-0.1Zr alloy with an ultimate tensile strength of 599.1 MPa,a uniform elongation of 8.6%,a microhardness of 195.7 HV_(0.2) and an electrical conductivity of 80.07%IACS was achieved by the continuous extrusion forming(CEF)and subsequent peak-aging treatment.The grain refinement strengthening,dislocation strengthening and precipitation strengthening are identified to be responsible for the excellent electrical and mechanical properties of Cu-Cr-Zr alloy.The wear behavior of Cu-Cr-Zr alloy was investigated by examining the evolution of worn surface morphology and subsurface microstructure.The microhardness(H)and reduced elastic modulus(E_(r))of the subsurface below the worn surface measured by nanoindentation were calculated to gage the tribological performance of Cu-Cr-Zr alloy.Results show that the continuously extruded and subsequently peak-aged specimen has the best wear resistance,which indicates that the tribological properties of CuCr-Zr alloy strongly depend on its strength and hardness.It can be concluded that the CEF and subsequent aging treatment process provides a new and high-efficiency procedure for the continuous preparation of Cu-Cr-Zr alloys.展开更多
基金supported by funds from The Ministry of Science and Technology of China (2017YFA0103900 and 2016YFA0502800)The National Natural Science Foundation of China (31571083)+6 种基金supported by The National Natural Science Foundation of China (81470701)The National Natural Science Foundation of China (81771882)The Program for Professor of Special Appointment (Eastern Scholar of Shanghai TP2014008)The Shanghai Rising-Star Program (14QA1400800)a grant from the Young 1000 Talent Program of China to ZYThe Fundamental Research (Discipline Layout) Foundation from Shenzhen Committee of Science, Technology and Innovation (JCYJ20170817111912585) to FC
文摘Drosophila dEAAT2, a member of the excitatory amino-acid transporter(EAAT) family, has been described as mediating the high-affinity transport of taurine, which is a free amino-acid abundant in both insects and mammals. However, the role of taurine and its transporter in hearing is not clear. Here, we report that dEAAT2 is required for the larval startle response to sound stimuli. d EAAT2 was found to be enriched in the distal region of chordotonal neurons where sound transduction occurs. The Ca^(2+) imaging and electrophysiological results showed that disrupted dEAAT2 expression significantly reduced the response of chordotonal neurons to sound.More importantly, expressing d EAAT2 in the chordotonal neurons rescued these mutant phenotypes. Taken together,these findings indicate a critical role for Drosophila dEAAT2 in sound transduction by chordotonal neurons.
基金supported financially by the National Key Research and Development Program(No.2018YFA0702900)the National Natural Science Foundation of China(Nos.U1508215,51774265 and 51701225)+3 种基金the National Science and Technology Major Project of China(No.2019ZX06004010)the Key Program of the Chinese Academy of Sciences(No.ZDRW-CN-2017-1)the Program of CAS Interdisciplinary Innovation TeamGleeble engineer Jiajun He for her technical support in superhot experiments.
文摘Semi-solid forging of iron-based alloys during solidification has unique characteristics distinct from those of the classical hot forging.With the aim of acquiring precise knowledge concerning the microstructural evolution of bearing steel Cr4 Mo4 V in this process,a series of semi-solid forging experiments were carried out in which samples were wrapped in a designed pure iron sheath.The effects of forging temperature and forging reduction on the grain morphology and liquid flow behavior were investigated,respectively.By forging solidifying metal(FSM),bulky primary dendrites were broken and spheroidal grains with an average shape factor of 0.87 were obtained at 1360?C.With the decreasing forging temperature to 1340?C,the microstructural homogeneity can be improved.On the other hand,it shows that a higher forging reduction(50%)is essential for the spheroidization of grains and elimination of liquid segregation.Those microstructural characteristics are related to different motion mechanisms of solid and liquid phases at different forging temperatures.Additionally,the effect of semi-solid forging on the eutectic carbides was also investigated,and the results demonstrate that the higher diffusion capacity and less liquid segregation jointly lower the large eutectic carbides and consequently cause its uniform distribution during FSM.
基金the financial support of the National Key Research and Development Program of China(Nos.2016YFB0300401,2018YFF0109404 and 2016YFB0301401)the National Natural Science Foundation of China(Nos.U1860202,U1732276,50134010,51704193,51904184 and 52004156)+1 种基金the Science and Technology Commission of Shanghai Municipality(Nos.13JC14025000 and 15520711000)the China Postdoctoral Science Foundation(No.2020M671072)。
文摘Detailed three-dimensional(3 D)microtomography characterizations of inclusions in electrode matrix,mushy zone(MZ)and liquid melt film(LMF)were performed to elucidate the motion and removal behavior of inclusions in electrode tip during magnetically controlled electroslag remelting(MC-ESR)process.A transient 2 D numerical model was also built to verify the experimental results and proposed mechanisms.The number and size of inclusions exhibited an obvious increasing trend from edge to mid region in LMF,while remained almost the same in electrode matrix and MZ.The inclusions in LMF migrated from edge to mid region of LMF,accompanied with removal process.In addition,the kinetic conditions for inclusion migrating to LMF/slag interface(LSI)were enhanced during MC-ESR process,thereby improving the inclusion removal efficiency in LMF.This work highlights the 3 D characterization and motion/removal mechanisms of inclusions in electrode tip,as well as sheds new light on preparing high purity materials.
基金financial support from the National Key Research and Development Program of China(Nos.2018YFF0109404,2016YFB0300401 and 2016YFB0301401)the National Natural Science Foundation of China(Nos.U1732276 and U1860202)+4 种基金financial support from the National Natural Science Foundation of China(No.51704193)financial support from the National Natural Science Foundation of China(No.52004156)financial support from the National Natural Science Foundation of China(No.51904184)the supports from the National Science Foundation(DMR-1611180)the US Army Research Office(W911NF-19-2-0049)。
文摘Over recent years,eutectic high-entropy alloys(EHEAs)have intrigued substantial research enthusiasms due to their good castability as well as balanced strength-ductility synergy.In this study,a bulk cast Al_(19.25)Co_(18.86)Fe_(18.36)Ni_(43.53)EHEA is developed with fine in-situ lamellar eutectics.The eutectics comprise alternating ordered face-centered-cubic(L1_(2))and ordered body-centered-cubic(B2)phases with semicoherent interfaces.The resulting microstructure resembles that of most reported as-cast EHEAs,but the B2 lamellae are devoid of nano-precipitates because of the Cr-element removal in current tailored eutectic composition.Surprisingly,the B2 lamellae still feature much higher deformation resistance than the L1_(2) lamellae,so that less lattice defects are detected in the B2 lamellae until the fracture.More interestingly,in the L1_(2) lamellae we identify a dynamic microstructure refinement that correlates to extraordinary strain hardening in tension.The precipitate-free EHEA consequently shows excellent tensile ductility of~10%and high ultimate strength up to~956 MPa.
基金This research was supported by the National Natural Science Foundation of China (Grant No. 41101532), Hunan Natural Science Foundation (No. 12JJ3036), Science and Technology Project of Xiangxi Tujia and Miao Autonomous District (Zhouke [2011] 42), and Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Mihistry of Education, China (Guikeneng 1002k003). We thank Professor AJM Baker (Universities of Melbourne and Queensland, Australia, and Sheffield, UK) for improving the final version of this paper.
基金financially supported by the National Key Research and Development Program of China(No.2016YFB0301401)the National Natural Science Foundation of China(Nos.U1860202,U1732276,50134010,51904184 and 52004156)the Science and Technology Commission of Shanghai Municipality(Nos.13JC14025000 and 15520711000)。
文摘As a promising material for the new generation of high-speed railway contact wires,the comprehensive optimization of the electrical conductivity,strength,hardness and wear resistance of the Cu-Cr-Zr alloy has received extensive attention.In this paper,a high-performance Cu-1Cr-0.1Zr alloy with an ultimate tensile strength of 599.1 MPa,a uniform elongation of 8.6%,a microhardness of 195.7 HV_(0.2) and an electrical conductivity of 80.07%IACS was achieved by the continuous extrusion forming(CEF)and subsequent peak-aging treatment.The grain refinement strengthening,dislocation strengthening and precipitation strengthening are identified to be responsible for the excellent electrical and mechanical properties of Cu-Cr-Zr alloy.The wear behavior of Cu-Cr-Zr alloy was investigated by examining the evolution of worn surface morphology and subsurface microstructure.The microhardness(H)and reduced elastic modulus(E_(r))of the subsurface below the worn surface measured by nanoindentation were calculated to gage the tribological performance of Cu-Cr-Zr alloy.Results show that the continuously extruded and subsequently peak-aged specimen has the best wear resistance,which indicates that the tribological properties of CuCr-Zr alloy strongly depend on its strength and hardness.It can be concluded that the CEF and subsequent aging treatment process provides a new and high-efficiency procedure for the continuous preparation of Cu-Cr-Zr alloys.