Plastic deformation of TiAI and TiAI-V intermetallic compounds has been studied by com- pression experiment at various temperatures and strain rates.Results show that the plastic deformation in distinct temperature ra...Plastic deformation of TiAI and TiAI-V intermetallic compounds has been studied by com- pression experiment at various temperatures and strain rates.Results show that the plastic deformation in distinct temperature range is principally controlled by the mechanisms of Peierls-Nabarro,cross slip and creep of dislocations.For TiAI-V alloy deformed at a range of 600—700 K,the negative strain rate dependence of flow stress was observed,i.e.,the more the plastic strain is.the more the negative dependence will be.A possible mechanism of the anomaly could be interpreted by thermal activation of dislocation cross slipping.The effects of temperature and strain rate on work-hardening exponent were also studied and discussed.展开更多
Based on SIMA, the Al-Si alloy semi-solid billets were successfully fabricated by means of strain inducement and isothermal treatment for AlSi9Mg poured in the range of near-liquidus. Through orthogonal test, the effe...Based on SIMA, the Al-Si alloy semi-solid billets were successfully fabricated by means of strain inducement and isothermal treatment for AlSi9Mg poured in the range of near-liquidus. Through orthogonal test, the effects of combination action of near-liquidus casting, strain inducement and isothermal treatment on the morphology of primaryα-Al phase of AlSi9Mg close to eutectic point were investigated, and the optimal match relation between the processing parameters of solidification, deformation parameters of strain inducement, processing parameters of isothermal treatment and microstructure parameters of semi-solid alloy was established. The results indicate that compared with the single near-liquidus casting or SIMA, the microstructure of primaryα-Al phase in AlSi9Mg alloy prepared by compound fabrication process is more homogeneous, with more globular and finer particles, which has average grain size of 40-50 urn and shape factor of greater than 0.75. After holding at 605℃for 30-40 min under a certain cooling rate, increased deformation volume in SIMA benefits the refinement of the grain and the improvement of the morphology for primary phase.展开更多
The genotoxic activities of effluents from drainage water treatment plants were examined by using the novel <em>umu</em> tester strain NM8001, which lacks <em>MutMst</em> genes. To enhance the ...The genotoxic activities of effluents from drainage water treatment plants were examined by using the novel <em>umu</em> tester strain NM8001, which lacks <em>MutMst</em> genes. To enhance the sensitivity of the LacZ assay, a BugBuster mix protein extraction reagent and TokyoGreen-<em>β</em> Gal for a fluorescence-galactosidase substrate were applied. Of the 24 sampling locations present in Kanagawa prefecture, Japan, water extracts from nine sampling points showed apparent genotoxic activities without metabolic activation. In contrast, water extracts from the upper sites of these water treatment plants did not show any significant genotoxic activities. The selected samples with genotoxic activity did not show significant mutagenicity toward Ames strains TA98 and TA100. Genotoxicity was also well correlated with the activity of a classical <em>umu </em>strain of TA1535/pSK1002;these findings indicate that the genotoxicity induced by oxidative damage was not a significant component of the genotoxicity.展开更多
Nine novel compounds,comprising seven tetrahydroanthraquinones(auxarthrolones A−G,1−7),aγ-butenolide glycoside(malfilamentoside E,26),and aγ-butenolide(auxarthrolide A,27),together with eighteen known compounds(8−25...Nine novel compounds,comprising seven tetrahydroanthraquinones(auxarthrolones A−G,1−7),aγ-butenolide glycoside(malfilamentoside E,26),and aγ-butenolide(auxarthrolide A,27),together with eighteen known compounds(8−25)were isolated from rice-based solid culture of Auxarthron umbrinum(A.umbrinum)DSM3193 using the one strain many compounds(OSMAC)approach.The structural elucidation of these compounds was accomplished through nuclear magnetic resonance(NMR),mass spectrometry(MS),and NMR calculation combined with DP4+analysis or MAEΔΔδparameter,while the absolute configurations of new compounds were established through single-crystal X-ray diffraction,electronic circular dichroism(ECD)spectroscopic data analysis and/or chemical derivatization.Austrocortilutein(10)and auxarthrol H(14)demonstrated moderate cytotoxicity against U87 and U251[half maximal inhibitory concentration(IC_(50))3.5−12.1μmol·L^(−1)].Additionally,auxarthrolone A(1),auxarthrol H(14),eupolyphagin B(15),and 7-hydroxy-2-(2-hydroxypropyl)-5-methylchromone(17)exhibited torsional effects on fibroblast proliferation challenges induced by oleic acid,thus demonstrating fibroblast proliferation-promoting activity.展开更多
文摘Plastic deformation of TiAI and TiAI-V intermetallic compounds has been studied by com- pression experiment at various temperatures and strain rates.Results show that the plastic deformation in distinct temperature range is principally controlled by the mechanisms of Peierls-Nabarro,cross slip and creep of dislocations.For TiAI-V alloy deformed at a range of 600—700 K,the negative strain rate dependence of flow stress was observed,i.e.,the more the plastic strain is.the more the negative dependence will be.A possible mechanism of the anomaly could be interpreted by thermal activation of dislocation cross slipping.The effects of temperature and strain rate on work-hardening exponent were also studied and discussed.
基金Project(04044058) supported by the Excellent Youths Science and Technology Foundation of Anhui, China
文摘Based on SIMA, the Al-Si alloy semi-solid billets were successfully fabricated by means of strain inducement and isothermal treatment for AlSi9Mg poured in the range of near-liquidus. Through orthogonal test, the effects of combination action of near-liquidus casting, strain inducement and isothermal treatment on the morphology of primaryα-Al phase of AlSi9Mg close to eutectic point were investigated, and the optimal match relation between the processing parameters of solidification, deformation parameters of strain inducement, processing parameters of isothermal treatment and microstructure parameters of semi-solid alloy was established. The results indicate that compared with the single near-liquidus casting or SIMA, the microstructure of primaryα-Al phase in AlSi9Mg alloy prepared by compound fabrication process is more homogeneous, with more globular and finer particles, which has average grain size of 40-50 urn and shape factor of greater than 0.75. After holding at 605℃for 30-40 min under a certain cooling rate, increased deformation volume in SIMA benefits the refinement of the grain and the improvement of the morphology for primary phase.
文摘The genotoxic activities of effluents from drainage water treatment plants were examined by using the novel <em>umu</em> tester strain NM8001, which lacks <em>MutMst</em> genes. To enhance the sensitivity of the LacZ assay, a BugBuster mix protein extraction reagent and TokyoGreen-<em>β</em> Gal for a fluorescence-galactosidase substrate were applied. Of the 24 sampling locations present in Kanagawa prefecture, Japan, water extracts from nine sampling points showed apparent genotoxic activities without metabolic activation. In contrast, water extracts from the upper sites of these water treatment plants did not show any significant genotoxic activities. The selected samples with genotoxic activity did not show significant mutagenicity toward Ames strains TA98 and TA100. Genotoxicity was also well correlated with the activity of a classical <em>umu </em>strain of TA1535/pSK1002;these findings indicate that the genotoxicity induced by oxidative damage was not a significant component of the genotoxicity.
基金supported by the National Key Research and Development Program of China(No.2018YFA0901900)the National Science Fund for Distinguished Young Scholars(No.82225042).
文摘Nine novel compounds,comprising seven tetrahydroanthraquinones(auxarthrolones A−G,1−7),aγ-butenolide glycoside(malfilamentoside E,26),and aγ-butenolide(auxarthrolide A,27),together with eighteen known compounds(8−25)were isolated from rice-based solid culture of Auxarthron umbrinum(A.umbrinum)DSM3193 using the one strain many compounds(OSMAC)approach.The structural elucidation of these compounds was accomplished through nuclear magnetic resonance(NMR),mass spectrometry(MS),and NMR calculation combined with DP4+analysis or MAEΔΔδparameter,while the absolute configurations of new compounds were established through single-crystal X-ray diffraction,electronic circular dichroism(ECD)spectroscopic data analysis and/or chemical derivatization.Austrocortilutein(10)and auxarthrol H(14)demonstrated moderate cytotoxicity against U87 and U251[half maximal inhibitory concentration(IC_(50))3.5−12.1μmol·L^(−1)].Additionally,auxarthrolone A(1),auxarthrol H(14),eupolyphagin B(15),and 7-hydroxy-2-(2-hydroxypropyl)-5-methylchromone(17)exhibited torsional effects on fibroblast proliferation challenges induced by oleic acid,thus demonstrating fibroblast proliferation-promoting activity.
