The effect of Si on the microstructure and mechanical properties of binary Al-4.5%Cu alloy has been investigated. The results show that the addition of Si does not have any effect on alloy strength; however, it decrea...The effect of Si on the microstructure and mechanical properties of binary Al-4.5%Cu alloy has been investigated. The results show that the addition of Si does not have any effect on alloy strength; however, it decreases the ductility of the as-cast Al-4.5%Cu alloy. It is obvious that after T4 heat treatment, the microstructure and mechanical properties of Al-4.5%Cu-Si alloys are improved, especially for the alloy with an Si addition of 2%.展开更多
The cultivated rice(Oryza sativa L.)is known to contain two major subspecies,indica(O. stativa L. ssp. indica)and japonica(O. sativa L. ssp.japonica). The indica and japonica differentiation
By using a set of 315 recombinant inbred lines (RILs) from the cross Lemont (japonica)×Teqing (indica) and a complete linkage map with 186 well distributed RFLP markers and 3 morphological markers, a major gene (...By using a set of 315 recombinant inbred lines (RILs) from the cross Lemont (japonica)×Teqing (indica) and a complete linkage map with 186 well distributed RFLP markers and 3 morphological markers, a major gene (Xa4) and 10 QTLs and 9 pairs of epistasis loci conferring horizontal resistance to three strains of \%Xanthomonas oryza\% pv \%oryza (Xoo)\% were mapped. The Teqing allele at Xa4 on chromosome 11 acts as a dominant resistant gene against pathogen race CR4 and CX08, but as an additive QTL with a significantly (47%) reduced effect \{against the\} virulent strain, CR6. The major gene Xa4 exhibited stronger degree of race specificity. Most QTLs showed consistent levels of resistance against all three \%Xoo\% strains. The results suggest that a high level durable resistance to \%Xoo\% may be achieved by cumulative effects of multiple QTL.展开更多
Heterostructured materials,defined as materials that contain multiple zones with dramatically different flow stresses,have the potential to push the envelope of the strength-ductility of metals and alloys beyond what ...Heterostructured materials,defined as materials that contain multiple zones with dramatically different flow stresses,have the potential to push the envelope of the strength-ductility of metals and alloys beyond what can be obtained conventionally[1–3].A prominent example is the heterogeneous lamella Ti that is as strong as its ultrafine-grained Ti,while as ductile as the coarsegrained Ti[4].展开更多
In order to obtain a glassy matrix during quenching, Be is often selected as a constituent of the compositions of Ti/Zr-based bulk metallic glass composites（BMGCs）. The in situ formed β phase in Be-bearing BMGCs wa...In order to obtain a glassy matrix during quenching, Be is often selected as a constituent of the compositions of Ti/Zr-based bulk metallic glass composites（BMGCs）. The in situ formed β phase in Be-bearing BMGCs was reported to be Be-free. However, a thorough investigation of the distribution of Be in BMGCs is still missing to date. In this work, the distribution of Be in a Ti_（47.5）Zr_（33）Cu_（5.8）Co_3Be_（12.5）（at.%） BMGC was studied by the secondary ion mass spectrometry（SIMS） and the electron energy loss spectroscopy（EELS）.It is found that Be almost totally dissolves in the glassy matrix, but a very weak intensity of Be in β phase is still detectable by SIMS, and the content of Be in β-Ti is estimated to be about 0.3 at.%. Based on the recently established two-phase quasi-equilibrium of BMGCs, the distinct solubility of Be in the glassy matrix and in β-Ti has been explained.展开更多
文摘The effect of Si on the microstructure and mechanical properties of binary Al-4.5%Cu alloy has been investigated. The results show that the addition of Si does not have any effect on alloy strength; however, it decreases the ductility of the as-cast Al-4.5%Cu alloy. It is obvious that after T4 heat treatment, the microstructure and mechanical properties of Al-4.5%Cu-Si alloys are improved, especially for the alloy with an Si addition of 2%.
文摘The cultivated rice(Oryza sativa L.)is known to contain two major subspecies,indica(O. stativa L. ssp. indica)and japonica(O. sativa L. ssp.japonica). The indica and japonica differentiation
文摘By using a set of 315 recombinant inbred lines (RILs) from the cross Lemont (japonica)×Teqing (indica) and a complete linkage map with 186 well distributed RFLP markers and 3 morphological markers, a major gene (Xa4) and 10 QTLs and 9 pairs of epistasis loci conferring horizontal resistance to three strains of \%Xanthomonas oryza\% pv \%oryza (Xoo)\% were mapped. The Teqing allele at Xa4 on chromosome 11 acts as a dominant resistant gene against pathogen race CR4 and CX08, but as an additive QTL with a significantly (47%) reduced effect \{against the\} virulent strain, CR6. The major gene Xa4 exhibited stronger degree of race specificity. Most QTLs showed consistent levels of resistance against all three \%Xoo\% strains. The results suggest that a high level durable resistance to \%Xoo\% may be achieved by cumulative effects of multiple QTL.
基金supported by the US Army Research Office[W911 NF-12-1-0009]financial support from the National Science Foundation(NSF)under award no.1929646performed in part at the AIF facility,which is supported by the State of North Carolina and the National Science Foundation[ECCS-1542015]
文摘Heterostructured materials,defined as materials that contain multiple zones with dramatically different flow stresses,have the potential to push the envelope of the strength-ductility of metals and alloys beyond what can be obtained conventionally[1–3].A prominent example is the heterogeneous lamella Ti that is as strong as its ultrafine-grained Ti,while as ductile as the coarsegrained Ti[4].
基金support from the National Natural Science Foundation of China (Nos. 51434008, U1435204, and 51531005)the China’s Manned Space Station Project (Mission No.: TGJZ800-2-RW024)the Shuangchuang Project of Jiangsu Province, China
文摘In order to obtain a glassy matrix during quenching, Be is often selected as a constituent of the compositions of Ti/Zr-based bulk metallic glass composites（BMGCs）. The in situ formed β phase in Be-bearing BMGCs was reported to be Be-free. However, a thorough investigation of the distribution of Be in BMGCs is still missing to date. In this work, the distribution of Be in a Ti_（47.5）Zr_（33）Cu_（5.8）Co_3Be_（12.5）（at.%） BMGC was studied by the secondary ion mass spectrometry（SIMS） and the electron energy loss spectroscopy（EELS）.It is found that Be almost totally dissolves in the glassy matrix, but a very weak intensity of Be in β phase is still detectable by SIMS, and the content of Be in β-Ti is estimated to be about 0.3 at.%. Based on the recently established two-phase quasi-equilibrium of BMGCs, the distinct solubility of Be in the glassy matrix and in β-Ti has been explained.
