Two contrasting cultivars of barley (Horderm vykgare L.): Kepin No. 7 (salt sensitive), and Jian 4 (salt tolerant) were grown in a hydroponics system with 2 NaCl levels: 60 mmol NaCl L-1 and 120 mmol NaCl L-1, and 3 S...Two contrasting cultivars of barley (Horderm vykgare L.): Kepin No. 7 (salt sensitive), and Jian 4 (salt tolerant) were grown in a hydroponics system with 2 NaCl levels: 60 mmol NaCl L-1 and 120 mmol NaCl L-1, and 3 Si levels: 0 mmol Si L-1, 0.5 mmol Si L-1 and 1.0 mmol Si L-1 (as silicic acid). Compared with the plants treated with 60 mmol NaCl L-1 alone, the leaf chlorophyll contents of plants treated with salt and Si increased significantly for salt-sensitive cultivar at tillering stage, but for salt-tolerant cultivar,the addition of Si resulted in an obvious increase in the leaf chlorophyll content of plants exposed to 120 mmol NaCl L-1. However, this Si-enhancement of leaf chlorophyll content was also observed in the salttolerant plants at jointing stage, but not in the salt-sensitive plants. Moreover, leaf chlorophyll content was consistently higher for the salt-tolerant cultivar than for the salt-sensitive cultivar irrespective of salt and/or Si treatment. Compared with the plants treated with salt alone, net CO2 assimilation rate in plant leaves increased significantly for both cultivars when trested with salt and Si. The addition of Si to the salt treatment was found to improve the cell ultrastructure of leaves. Under salt stress condition, the double membranes of chloroplasts disappeared, but membrane integrity was markedly improved in the salt treatment supplemented with Si. Silicon was also found to ameliorate the damage to the ultrastructure of chloroplast granae which appeared to be disintegrated and vague in salt treatments without added Si. The results support previous work which showed that Si decreases the permeability of plasma membranes of salt-stressed barley, thus mitigating salt damage.展开更多
Silicon carbide ceramics were prepared with SiC powder treated by the fluidized bed opposed jet mill as raw materials, and the effects of the ultra-fine treatment mechanism on the compaction and sintering behavior of ...Silicon carbide ceramics were prepared with SiC powder treated by the fluidized bed opposed jet mill as raw materials, and the effects of the ultra-fine treatment mechanism on the compaction and sintering behavior of SiC ceramics were investigated. The results showed that the compacts had higher density and microstructure homogeneity when the sintering temperature of the compact was decreased; and that the surface microstructure, densification and mechanical properties of the sintered body could be ameliorated obviously.展开更多
Nanometer chips were directly fabricated using face nanogrinding carried out by ultrafine diamond grits at room temperature. Direct evidence for ground nanometer chips is cuboid, and the average ratio of width to thic...Nanometer chips were directly fabricated using face nanogrinding carried out by ultrafine diamond grits at room temperature. Direct evidence for ground nanometer chips is cuboid, and the average ratio of width to thickness is 1.49. Chips of 9.0 nm in thickness, 13.3 nm in width, and 16.0 in diagonal were achieved and confirmed using transmission electron microscopy. Based on the nanometer chips observed, a model was proposed according to the mass conservation and fundamental mechanism of face grinding. The surface roughness and thickness of damaged layers measured experimentally are in good agreement with the prediction of the developed model. The feed rate significantly affects the surface roughness and thickness of damaged layers, when keeping the wheel and table speeds constant, respectively.展开更多
文摘Two contrasting cultivars of barley (Horderm vykgare L.): Kepin No. 7 (salt sensitive), and Jian 4 (salt tolerant) were grown in a hydroponics system with 2 NaCl levels: 60 mmol NaCl L-1 and 120 mmol NaCl L-1, and 3 Si levels: 0 mmol Si L-1, 0.5 mmol Si L-1 and 1.0 mmol Si L-1 (as silicic acid). Compared with the plants treated with 60 mmol NaCl L-1 alone, the leaf chlorophyll contents of plants treated with salt and Si increased significantly for salt-sensitive cultivar at tillering stage, but for salt-tolerant cultivar,the addition of Si resulted in an obvious increase in the leaf chlorophyll content of plants exposed to 120 mmol NaCl L-1. However, this Si-enhancement of leaf chlorophyll content was also observed in the salttolerant plants at jointing stage, but not in the salt-sensitive plants. Moreover, leaf chlorophyll content was consistently higher for the salt-tolerant cultivar than for the salt-sensitive cultivar irrespective of salt and/or Si treatment. Compared with the plants treated with salt alone, net CO2 assimilation rate in plant leaves increased significantly for both cultivars when trested with salt and Si. The addition of Si to the salt treatment was found to improve the cell ultrastructure of leaves. Under salt stress condition, the double membranes of chloroplasts disappeared, but membrane integrity was markedly improved in the salt treatment supplemented with Si. Silicon was also found to ameliorate the damage to the ultrastructure of chloroplast granae which appeared to be disintegrated and vague in salt treatments without added Si. The results support previous work which showed that Si decreases the permeability of plasma membranes of salt-stressed barley, thus mitigating salt damage.
文摘Silicon carbide ceramics were prepared with SiC powder treated by the fluidized bed opposed jet mill as raw materials, and the effects of the ultra-fine treatment mechanism on the compaction and sintering behavior of SiC ceramics were investigated. The results showed that the compacts had higher density and microstructure homogeneity when the sintering temperature of the compact was decreased; and that the surface microstructure, densification and mechanical properties of the sintered body could be ameliorated obviously.
基金supported by the National Natural Science Foundation of China (Grant No. 91123013)Tribology Science Fund of State Key Laboratory of Tribology (Grant No. SKLTKF12A08) (Tsinghua University)+1 种基金Fund of State Key Laboratory of Metastable Materials Science and Technology (Grant No. 201302) (Yanshan University)the Fundamental Research Funds for the Central Universities (Grant No. DUT13YQ109)
文摘Nanometer chips were directly fabricated using face nanogrinding carried out by ultrafine diamond grits at room temperature. Direct evidence for ground nanometer chips is cuboid, and the average ratio of width to thickness is 1.49. Chips of 9.0 nm in thickness, 13.3 nm in width, and 16.0 in diagonal were achieved and confirmed using transmission electron microscopy. Based on the nanometer chips observed, a model was proposed according to the mass conservation and fundamental mechanism of face grinding. The surface roughness and thickness of damaged layers measured experimentally are in good agreement with the prediction of the developed model. The feed rate significantly affects the surface roughness and thickness of damaged layers, when keeping the wheel and table speeds constant, respectively.
