Based on the fact that Fe toxicity which is usually characterized by leaf oranging and low yield canbe obviously subdued by application of Si or Mn due to counteraction between Fe and Si or Mn. A potexperiment was con...Based on the fact that Fe toxicity which is usually characterized by leaf oranging and low yield canbe obviously subdued by application of Si or Mn due to counteraction between Fe and Si or Mn. A potexperiment was conducted with four treatments of CK, Si, Mn and Si+Mn to further study the effect ofcombined application of Si and Mn on rice growth on red earths. Water-soluble Si, Fe and Mn were measured,and electron probe was used to study Si, Mn, Fe and Ca in root cross sections. Combined application of Si andMn could increase water-soluble Si and Mn but reduce water-soluble Fe, thus being favorable for correctingFe toxicity. Electron probe study showed obvious differences of Si, Fe, Mn and Ca in rice roots betweenCK and the other three treatments. The combined application of Si and Mn could reduce leaf oranging andimprove rice growth. The Si+Mn treatment had a higher plant height, lower number of oranging leaves anda 25.0% higher rice yield than CK and showed a better effect on rice growth than the treatment of sole Si orMn.展开更多
An experiment using rhizobox was conducted to study Si, Fe and Mn distributions in rice rhizosphcre of red earths and paddy soils. It was found that Si, Fe and Mn distributions in rhizosphere of the paddy soils were c...An experiment using rhizobox was conducted to study Si, Fe and Mn distributions in rice rhizosphcre of red earths and paddy soils. It was found that Si, Fe and Mn distributions in rhizosphere of the paddy soils were characterized by a depleted zone around root surface, beyond which the concentrations gradually rose. From lmm layer to 2mm layer the concentrations dropped and then rose again. Whereas Si and Fe in red earths showed no depleted zone but even accumulated zone around root surface. Mn showed an approximately even distribution in each layer and no depletion was found in root surface layers. This indicated that during rice (Oryza sativa L.)plantation, depletion and accumulation of Si, Fe and Mn in rhizosphere were important features of matured red earths by water culture. The distribution changes of Si, Fe and Mn in relation to soil-root interaction are also discussed.展开更多
Fe-C-Si-Mn alloy castings used as blades in hydroelectric generators are studied and found to contain network structures after some heat treatments. Castings after annealing and normalizing were analyzed by microscope...Fe-C-Si-Mn alloy castings used as blades in hydroelectric generators are studied and found to contain network structures after some heat treatments. Castings after annealing and normalizing were analyzed by microscope and transmission electron microscopy (TEM). The network formed during annealing was proved by TEM to be pearlite with very fine slices, while that formed during normalizing was proved by TEM and micro-hardness to be martensite or bainite. A theoretical analysis together with experimental studies has proved that the pearlite network is caused by carbon content increase in the interdendritic regions to which carbon atoms transfered from dendritic arms due to lower manganese content there during annealing, while the martensite or bainite network results from the higher hardenability of interdendritic regions where manganese content is higher. Experiments reveal that higher heating temperature or longer heating time enlarges the network size due to manganese homogenization. The network structure has a strengthening function like reinforcing rib, and the smaller the network size, the greater its strengthening capability.展开更多
Low grade siliceous manganese ores from the iron ore group of the Bonai-Keonjhar belt, Orissa, India are found mostly in shear zones. The ore characteristics of siliceous manganese ore samples from three differ- ent m...Low grade siliceous manganese ores from the iron ore group of the Bonai-Keonjhar belt, Orissa, India are found mostly in shear zones. The ore characteristics of siliceous manganese ore samples from three differ- ent mines, viz. the Shankar (Barbil OMC lease hold area), the Sone-Patuli (Patmunda, OMM lease hold area), and the Musaghar (Roida, OMDC lease hold area), were studied. These siliceous manganese ores are of three types, respectively: (i) spongy-granular; (ii) massive-mosaic; and (iii) hard-mylonitized. The spongy-gran- ular type contains granular, saccharoidal quartz and the major manganese mineral present is pyrolusite. The second type contains well crystallized quartz and cryptomelane, while the third has cherty, fine grained quartz (mylonite) along with romanechite. All three ores were subjected to physical beneficiation under similar conditions. Both gravity and magnetic separation techniques were employed. The mineral-fabric of the ores has been correlated to the extent of their beneficiation using these physical techniques. Of these three ores only the spongy-granular type responded well to upgrading. The feed with 22% Mn content could be upgraded to 44% with a 28% yield and a 49% recovery. The good response to beneficiation of the spongy- granular sample could be due to the large euhedral crystals of pyrolusite and the friable nature of the sac- charoidal quartz. This study reveals the influence of mineral-fabric on beneficiation of low grade ore, siliceous Mn ore in particular.展开更多
The mineralogical and micromorphological characteristics of Si-Fe-Mn oxyhydroxides from the dacite-hosted PACMANUS hydrothermal field were analyzed.The samples are poorly crystallized Si-Fe-Mn oxyhydroxides with minor...The mineralogical and micromorphological characteristics of Si-Fe-Mn oxyhydroxides from the dacite-hosted PACMANUS hydrothermal field were analyzed.The samples are poorly crystallized Si-Fe-Mn oxyhydroxides with minor birnessite, todorokite, nontronite, goethite, and opal-A.There are some microtextures which are rather like fossil microbes such as the filamentous silica and the hollow pipes.Flakes of nontronite crystals are found either forming a honeycomb texture or distrib- uted on the surface of the hollow pipes.Nontronite is the product precipitated from low-temperature hydrothermal fluids, and microbes may play a role in its formation.Si-Fe-Mn oxyhydroxides have two kinds of nuclei: Si-Mn nuclei and Si nuclei, both enveloped by the similar Si-Fe outer layer, existing in the rod-shaped oxyhydroxide and spheroidal oxyhydroxide, respectively.In the Si-Mn nuclei, the concentration of SiO2 is between 39.32 wt% and 86.31 wt%, and MnO concentration is between 4.97 wt% and 27.01 wt%, but Fe2O3 concentration is very low (0.54 wt%-3.43 wt%).In the Si nucleus the concentration of SiO2 is 90.17 wt%, but concentration of MnO and Fe2O3 are low, with 0.06 wt% and 3.47 wt%, respectively.The formation of the Si-Mn nucleus is closely related to microbes, whereas the Si nucleus is of inorganic origin.展开更多
The stainless Fe-Mn-Si shape memory alloy(SMA) coating was prepared on the surface of AISI 304 stainless steel. The principal residual stress measured by the mechanical hole-drilling method indicates that the Fe-Mn-Si...The stainless Fe-Mn-Si shape memory alloy(SMA) coating was prepared on the surface of AISI 304 stainless steel. The principal residual stress measured by the mechanical hole-drilling method indicates that the Fe-Mn-Si SMA cladding specimen possesses a lower residual stress compared with the 304 stainless steel cladding specimen. The mean stress values of the former and the latter on 10-mm-thick substrate are 4.751 MPa and 7.399 MPa, respectively. What's more, their deformation values on 2-mm-thick substrate are about 0° and 15°, respectively. Meanwhile, the variation trend and the value of the residual stress simulated by the ANSYS finite element software consist with experimental results. The X-ray diffraction(XRD) pattern shows ε-martensite exists in Fe-Mn-Si SMA coating, which verifies the mechanism of low residual stress. That's the γ→ε martensite phase transformation, which relaxes the residual stress of the specimen and reduces its deformation in the laser cladding processing.展开更多
文摘Based on the fact that Fe toxicity which is usually characterized by leaf oranging and low yield canbe obviously subdued by application of Si or Mn due to counteraction between Fe and Si or Mn. A potexperiment was conducted with four treatments of CK, Si, Mn and Si+Mn to further study the effect ofcombined application of Si and Mn on rice growth on red earths. Water-soluble Si, Fe and Mn were measured,and electron probe was used to study Si, Mn, Fe and Ca in root cross sections. Combined application of Si andMn could increase water-soluble Si and Mn but reduce water-soluble Fe, thus being favorable for correctingFe toxicity. Electron probe study showed obvious differences of Si, Fe, Mn and Ca in rice roots betweenCK and the other three treatments. The combined application of Si and Mn could reduce leaf oranging andimprove rice growth. The Si+Mn treatment had a higher plant height, lower number of oranging leaves anda 25.0% higher rice yield than CK and showed a better effect on rice growth than the treatment of sole Si orMn.
基金Project supported by the National Natural Science Foundation of Chinathe Laboratory of Material Cycling in Pedosphere.Academia Sinica.
文摘An experiment using rhizobox was conducted to study Si, Fe and Mn distributions in rice rhizosphcre of red earths and paddy soils. It was found that Si, Fe and Mn distributions in rhizosphere of the paddy soils were characterized by a depleted zone around root surface, beyond which the concentrations gradually rose. From lmm layer to 2mm layer the concentrations dropped and then rose again. Whereas Si and Fe in red earths showed no depleted zone but even accumulated zone around root surface. Mn showed an approximately even distribution in each layer and no depletion was found in root surface layers. This indicated that during rice (Oryza sativa L.)plantation, depletion and accumulation of Si, Fe and Mn in rhizosphere were important features of matured red earths by water culture. The distribution changes of Si, Fe and Mn in relation to soil-root interaction are also discussed.
文摘Fe-C-Si-Mn alloy castings used as blades in hydroelectric generators are studied and found to contain network structures after some heat treatments. Castings after annealing and normalizing were analyzed by microscope and transmission electron microscopy (TEM). The network formed during annealing was proved by TEM to be pearlite with very fine slices, while that formed during normalizing was proved by TEM and micro-hardness to be martensite or bainite. A theoretical analysis together with experimental studies has proved that the pearlite network is caused by carbon content increase in the interdendritic regions to which carbon atoms transfered from dendritic arms due to lower manganese content there during annealing, while the martensite or bainite network results from the higher hardenability of interdendritic regions where manganese content is higher. Experiments reveal that higher heating temperature or longer heating time enlarges the network size due to manganese homogenization. The network structure has a strengthening function like reinforcing rib, and the smaller the network size, the greater its strengthening capability.
文摘Low grade siliceous manganese ores from the iron ore group of the Bonai-Keonjhar belt, Orissa, India are found mostly in shear zones. The ore characteristics of siliceous manganese ore samples from three differ- ent mines, viz. the Shankar (Barbil OMC lease hold area), the Sone-Patuli (Patmunda, OMM lease hold area), and the Musaghar (Roida, OMDC lease hold area), were studied. These siliceous manganese ores are of three types, respectively: (i) spongy-granular; (ii) massive-mosaic; and (iii) hard-mylonitized. The spongy-gran- ular type contains granular, saccharoidal quartz and the major manganese mineral present is pyrolusite. The second type contains well crystallized quartz and cryptomelane, while the third has cherty, fine grained quartz (mylonite) along with romanechite. All three ores were subjected to physical beneficiation under similar conditions. Both gravity and magnetic separation techniques were employed. The mineral-fabric of the ores has been correlated to the extent of their beneficiation using these physical techniques. Of these three ores only the spongy-granular type responded well to upgrading. The feed with 22% Mn content could be upgraded to 44% with a 28% yield and a 49% recovery. The good response to beneficiation of the spongy- granular sample could be due to the large euhedral crystals of pyrolusite and the friable nature of the sac- charoidal quartz. This study reveals the influence of mineral-fabric on beneficiation of low grade ore, siliceous Mn ore in particular.
基金supported by National Natural Science Foundation of China(Grant No.40830849)National Key Basic Research Program of China(Grant No.2013CB429700)+1 种基金Shandong Province Natural Science Foundation of China for Distin-guished Young Scholars(Grant No.JQ200913)the Pilot Project of Knowledge Innovation Project,Chinese Academy of Sciences(Grant No.KZCX2-YW-211)
文摘The mineralogical and micromorphological characteristics of Si-Fe-Mn oxyhydroxides from the dacite-hosted PACMANUS hydrothermal field were analyzed.The samples are poorly crystallized Si-Fe-Mn oxyhydroxides with minor birnessite, todorokite, nontronite, goethite, and opal-A.There are some microtextures which are rather like fossil microbes such as the filamentous silica and the hollow pipes.Flakes of nontronite crystals are found either forming a honeycomb texture or distrib- uted on the surface of the hollow pipes.Nontronite is the product precipitated from low-temperature hydrothermal fluids, and microbes may play a role in its formation.Si-Fe-Mn oxyhydroxides have two kinds of nuclei: Si-Mn nuclei and Si nuclei, both enveloped by the similar Si-Fe outer layer, existing in the rod-shaped oxyhydroxide and spheroidal oxyhydroxide, respectively.In the Si-Mn nuclei, the concentration of SiO2 is between 39.32 wt% and 86.31 wt%, and MnO concentration is between 4.97 wt% and 27.01 wt%, but Fe2O3 concentration is very low (0.54 wt%-3.43 wt%).In the Si nucleus the concentration of SiO2 is 90.17 wt%, but concentration of MnO and Fe2O3 are low, with 0.06 wt% and 3.47 wt%, respectively.The formation of the Si-Mn nucleus is closely related to microbes, whereas the Si nucleus is of inorganic origin.
基金supported by the Fundamental Research Funds for the Central Universities of China(No.3132016354)
文摘The stainless Fe-Mn-Si shape memory alloy(SMA) coating was prepared on the surface of AISI 304 stainless steel. The principal residual stress measured by the mechanical hole-drilling method indicates that the Fe-Mn-Si SMA cladding specimen possesses a lower residual stress compared with the 304 stainless steel cladding specimen. The mean stress values of the former and the latter on 10-mm-thick substrate are 4.751 MPa and 7.399 MPa, respectively. What's more, their deformation values on 2-mm-thick substrate are about 0° and 15°, respectively. Meanwhile, the variation trend and the value of the residual stress simulated by the ANSYS finite element software consist with experimental results. The X-ray diffraction(XRD) pattern shows ε-martensite exists in Fe-Mn-Si SMA coating, which verifies the mechanism of low residual stress. That's the γ→ε martensite phase transformation, which relaxes the residual stress of the specimen and reduces its deformation in the laser cladding processing.
