Using potted seedlings of Chlorophytum comosum var. variegatum as the experimental materials, the effect of 2.0 mmol/L methyl orange （ Treatment T1 ）, 1.0 mmol/L methyl violet （ Treatment T2 ） and 1.0 mmol/L neutr...Using potted seedlings of Chlorophytum comosum var. variegatum as the experimental materials, the effect of 2.0 mmol/L methyl orange （ Treatment T1 ）, 1.0 mmol/L methyl violet （ Treatment T2 ） and 1.0 mmol/L neutral red （ Treatment T3 ） on the biomass, root-shoot ratio, leaf color indices, plant carbon and nitrogen nutrition were studied. The results showed that the biomass of Treatment T3 was significantly greater than that of treatments T1 and CK. The root-shoot ratio decreased significantly in treatments T1, T2 and T3 , and the decrease in T3 was most obvious. In all the three treatments with coloring agent, a ^＊ , b ^＊ and L ^＊ values were increased gradually, C value were decreased, H0 and CIRG were increased, and the leaves were pink. In addition, the contents of chlorophyll a, chlorophyll b, chlorophyll a ＋ b and carotenoid were significantly decreased. The contents of soluble sugar and starch were also decreased, and the decrease in Treatment T2 was most significant. The contents of soluble protein and total nitrogen were increased, and the increase was most dramatic in Treatment T3. The carbon to nitrogen ratio was decreased. The results proved that staining can improve the ornamental value of indoor plants, despite its effects on plant carbon and nitrogen nutrition of C. comosum vat. variegatum, dyeing.展开更多
Silicon(Si)is an inevitable impurity element in the AZ31 alloy.In this study,the Si impurity was detected mainly as fine Mg_(2)Si particles dispersed widely within the central region of the Mg_(17)Al_(12) phase.During...Silicon(Si)is an inevitable impurity element in the AZ31 alloy.In this study,the Si impurity was detected mainly as fine Mg_(2)Si particles dispersed widely within the central region of the Mg_(17)Al_(12) phase.During the solidification process,the Mg_(2)Si particle precipitates at about 565℃,before the Mg_(17)Al_(12) phase of 186℃,potentially acting as the heterogeneous nucleation core for the Mg_(17)Al_(12) phase.The orientation relationship between Mg_(2)Si and Mg_(17)Al_(12) was investigated using the Edge-to-Edge matching model(E2EM)calculations,which showed a misfit of only 0.1%.This low misfit suggests that Mg_(2)Si can serve as a heterogeneous nucleation site for Mg_(17)Al_(12).The surface and interface structures of Mg_(2)Si(220)and Mg_(17)Al_(12)(332)were constructed,and then investigated through the first-principles calculation.The theoretical results indicate that Mg and Al are easily adsorbed on the surface of Mg_(2)Si,with Al showing higher adsorption energy than Mg.Furthermore,the interface between Mg_(2)Si and Mg_(17)Al_(12) exhibits favorable thermodynamic stability.Combined with experiments and theoretical calculations,it is confirmed that the Mg_(2)Si particles,formed due to the Si impurity,provide effective heterogeneous nucleation sites for the Mg_(17)Al_(12) phase.展开更多
This study revealed the nucleation event and grain refinement mechanism of Mg-Al alloy induced by Fe impurity.The following orientation relationship was observed between Al-Fe particle andα-Mg matrix in the Mg-3Al al...This study revealed the nucleation event and grain refinement mechanism of Mg-Al alloy induced by Fe impurity.The following orientation relationship was observed between Al-Fe particle andα-Mg matrix in the Mg-3Al alloy containing Fe impurity using a focused ion beam aided transmission electron microscope technique:(1^(-)011)[011^(-)1]_(Mg)//(011^(-))[011]_(Al_(2)Fe).Mg-3Al alloy was inoculated by adding 0.02wt%Fe to verify the nucleating potency of the Al_(2)Fe phase forα-Mg grain.The results indicated that Mg-3Al alloy was effectively refined with an average grain size declining from 1135 to 540μm.Among the potential Al-Fe phases of Mg-3Al-0.02Fe alloy,only the precipitation of the Al_(2)Fe phase occurs earlier than that ofα-Mg grain,and the Al_(2)Fe phase is stable in the nucleation stage ofα-Mg grain.Therefore,the Al_(2)Fe particle is the only available nucleating site for Mg-Al alloy with Fe impurity.The heterogeneous nucleation event ofα-Mg grain on the Al_(2)Fe particle is responsible for the grain refinement of Mg-3Al alloy inoculated by Fe.展开更多
The introduction of oxide inclusions during the smelting process has a clear promising heterogeneous nucleation potency on Mg-based alloys, but the mechanism has not been explored clearly yet. In the present work, the...The introduction of oxide inclusions during the smelting process has a clear promising heterogeneous nucleation potency on Mg-based alloys, but the mechanism has not been explored clearly yet. In the present work, the grain refinement mechanism of MgO in pure Mg,Mg-3Al and AZ31(Mg-2.9Al-0.9Zn-0.3Mn) alloys is investigated by combing first-principles calculations and experiments. The theoretical results show that solute atoms adsorption will affect the nucleation and the subsequent growth process, which is an important factor affecting the refinement efficiency. A contradiction between the experimental results and the grain growth restriction factor(GRF) theory is observed,that is the refinement ratio of AZ31 is worse than Mg-3Al alloy. This is explained by an adsorption model which reveals that Al promotes the adsorption of Mg on MgO surface so as to stimulate more particles available as nucleating sites. Meanwhile, Fe and Mn also have favorable effects on the adsorption of Mg, Zn may play the opposite role compared to Al. The theoretical analyzes provide a strong support to the experiments that Al benefits the initial nucleation of α-Mg on MgO to promote the grain refining effect of Mg-3Al prior to AZ31 alloy.展开更多
文摘Using potted seedlings of Chlorophytum comosum var. variegatum as the experimental materials, the effect of 2.0 mmol/L methyl orange （ Treatment T1 ）, 1.0 mmol/L methyl violet （ Treatment T2 ） and 1.0 mmol/L neutral red （ Treatment T3 ） on the biomass, root-shoot ratio, leaf color indices, plant carbon and nitrogen nutrition were studied. The results showed that the biomass of Treatment T3 was significantly greater than that of treatments T1 and CK. The root-shoot ratio decreased significantly in treatments T1, T2 and T3 , and the decrease in T3 was most obvious. In all the three treatments with coloring agent, a ^＊ , b ^＊ and L ^＊ values were increased gradually, C value were decreased, H0 and CIRG were increased, and the leaves were pink. In addition, the contents of chlorophyll a, chlorophyll b, chlorophyll a ＋ b and carotenoid were significantly decreased. The contents of soluble sugar and starch were also decreased, and the decrease in Treatment T2 was most significant. The contents of soluble protein and total nitrogen were increased, and the increase was most dramatic in Treatment T3. The carbon to nitrogen ratio was decreased. The results proved that staining can improve the ornamental value of indoor plants, despite its effects on plant carbon and nitrogen nutrition of C. comosum vat. variegatum, dyeing.
基金supported by the National Natural Science Foundation of China(Nos.51871100 and 12074126).
文摘Silicon(Si)is an inevitable impurity element in the AZ31 alloy.In this study,the Si impurity was detected mainly as fine Mg_(2)Si particles dispersed widely within the central region of the Mg_(17)Al_(12) phase.During the solidification process,the Mg_(2)Si particle precipitates at about 565℃,before the Mg_(17)Al_(12) phase of 186℃,potentially acting as the heterogeneous nucleation core for the Mg_(17)Al_(12) phase.The orientation relationship between Mg_(2)Si and Mg_(17)Al_(12) was investigated using the Edge-to-Edge matching model(E2EM)calculations,which showed a misfit of only 0.1%.This low misfit suggests that Mg_(2)Si can serve as a heterogeneous nucleation site for Mg_(17)Al_(12).The surface and interface structures of Mg_(2)Si(220)and Mg_(17)Al_(12)(332)were constructed,and then investigated through the first-principles calculation.The theoretical results indicate that Mg and Al are easily adsorbed on the surface of Mg_(2)Si,with Al showing higher adsorption energy than Mg.Furthermore,the interface between Mg_(2)Si and Mg_(17)Al_(12) exhibits favorable thermodynamic stability.Combined with experiments and theoretical calculations,it is confirmed that the Mg_(2)Si particles,formed due to the Si impurity,provide effective heterogeneous nucleation sites for the Mg_(17)Al_(12) phase.
基金financially supported by the National Natural Science Foundation of China(No.51871100)。
文摘This study revealed the nucleation event and grain refinement mechanism of Mg-Al alloy induced by Fe impurity.The following orientation relationship was observed between Al-Fe particle andα-Mg matrix in the Mg-3Al alloy containing Fe impurity using a focused ion beam aided transmission electron microscope technique:(1^(-)011)[011^(-)1]_(Mg)//(011^(-))[011]_(Al_(2)Fe).Mg-3Al alloy was inoculated by adding 0.02wt%Fe to verify the nucleating potency of the Al_(2)Fe phase forα-Mg grain.The results indicated that Mg-3Al alloy was effectively refined with an average grain size declining from 1135 to 540μm.Among the potential Al-Fe phases of Mg-3Al-0.02Fe alloy,only the precipitation of the Al_(2)Fe phase occurs earlier than that ofα-Mg grain,and the Al_(2)Fe phase is stable in the nucleation stage ofα-Mg grain.Therefore,the Al_(2)Fe particle is the only available nucleating site for Mg-Al alloy with Fe impurity.The heterogeneous nucleation event ofα-Mg grain on the Al_(2)Fe particle is responsible for the grain refinement of Mg-3Al alloy inoculated by Fe.
基金supported by the National Natural Science Foundation of China (No.51871100)。
文摘The introduction of oxide inclusions during the smelting process has a clear promising heterogeneous nucleation potency on Mg-based alloys, but the mechanism has not been explored clearly yet. In the present work, the grain refinement mechanism of MgO in pure Mg,Mg-3Al and AZ31(Mg-2.9Al-0.9Zn-0.3Mn) alloys is investigated by combing first-principles calculations and experiments. The theoretical results show that solute atoms adsorption will affect the nucleation and the subsequent growth process, which is an important factor affecting the refinement efficiency. A contradiction between the experimental results and the grain growth restriction factor(GRF) theory is observed,that is the refinement ratio of AZ31 is worse than Mg-3Al alloy. This is explained by an adsorption model which reveals that Al promotes the adsorption of Mg on MgO surface so as to stimulate more particles available as nucleating sites. Meanwhile, Fe and Mn also have favorable effects on the adsorption of Mg, Zn may play the opposite role compared to Al. The theoretical analyzes provide a strong support to the experiments that Al benefits the initial nucleation of α-Mg on MgO to promote the grain refining effect of Mg-3Al prior to AZ31 alloy.
