Based on ANSYS FEM software, the distribution of residual stress in the diffusion bonding joints between Ti（ C,N） metallic ceramic/interlayer/4OCr steel was calculated and experimentally ver^ed. The results showed t...Based on ANSYS FEM software, the distribution of residual stress in the diffusion bonding joints between Ti（ C,N） metallic ceramic/interlayer/4OCr steel was calculated and experimentally ver^ed. The results showed that the trend on the distribution of residual stress field in the joints was not changed with the use of interlayer. The maximum residual stress was always located in metallic ceramic with area ranging from 1 mm to 4 mm to the interlayer. The maximum residual stress in the joints was also affected by diffusion temperature. The satellite pulse current during the initial stage on diffusion bonding can promote the formation of liquid film at the interface, by which diffusion temperature and loading pressure can be greatly decreased. The crack initiation was easily produced at the corner of Ti （ C, N） metallic ceramic close to the interlayer. If a higher residual stress produced in the joints, the crack was propagated into the whole ceramic.展开更多
Fe-based alloy coatings reinforced by Ti（ C, N） particles was produced through CO2 laser cladding technology. The microstructure of laser cladding coating was analyzed by means of X-ray diffraction （ XRD ）, transm...Fe-based alloy coatings reinforced by Ti（ C, N） particles was produced through CO2 laser cladding technology. The microstructure of laser cladding coating was analyzed by means of X-ray diffraction （ XRD ）, transmission electron microscopy （TEM） , selected area electron diffraction （ SAED ） , scanning electron microscopy （SEM） and electron probe microscopic analyzer （ EPMA ）. The mechanical property of the layer was measured by using microhardness meter. The results show that Ti （ C0. 3 N0. 7 ） panicles are introduced by an in-situ metallurgical reaction between TiN particle and graphite powder during laser cladding process. Titanium carbonitrides particles existed in the layer are fairly fine, ranging from 0. 1 μm to 5.0 μm, and evenly dispersed in the metal α-Fe matrix. Most of them take on nearly rhombus shape, and some of them are irregular in shape. The microhardness of laser cladding layer ranges from 770 HV0. 3 to 850 HV0. 3.展开更多
To study non-structural carbohydrate character-istics and nutrient utilization strategies of Pinus yunnanen-sis under continuous drought conditions,2-year-old seed-lings were planted in pots with appropriate water,lig...To study non-structural carbohydrate character-istics and nutrient utilization strategies of Pinus yunnanen-sis under continuous drought conditions,2-year-old seed-lings were planted in pots with appropriate water,light and moderate and severe drought treatments[(80±5),(65±5),(50±5),and(35±5)%of field water-holding capacity].Non-structural carbohydrates,carbon(C),nitrogen(N),and phosphorus(P)concentrations were measured in each plant component.The results show that:(1)With increasing drought,non-structural carbohydrates gradually increased in leaves,stems,and coarse roots,while gradually decreased in fine roots;(2)C concentrations of all were relatively stable under different stress levels.Phosphorous utilization of each component increased under light and moderate drought conditions,while N and P utilization efficiency of each plant component decreased under severe drought.Growth was mainly restricted by N,first decreasing and then increasing with increased drought;(3)There was a correlation between the levels of non-structural carbohydrates and C,N,and P in each component.Changes in N concentration affected the interconversion between soluble sugar and starch,which play a regulatory role in the fluctuation of the concentration of non-structural carbohydrates;and,(4)Plasticity analysis showed that P.yunnanensis seedlings responded to drought mainly by altering starch concentration,the ratio of soluble sugar to starch in leaves and stems,and further by alter-ing N and P utilization efficiencies.Overall,these results suggest that the physiological activities of all organs of P.yunnanensis seedlings are restricted under drought and that trade-offs exist between different physiological indicators and organs.Our findings are helpful in understanding non-structural carbohydrate and nutrient adaptation mechanisms under drought in P.yunnanensis seedlings.展开更多
基金The authors are grateful to the financial support for this research from National Natural Science Foundation of China （Grant No. 51175259） , Jiangsu Science and Technology Planning Project （No. BK2011494） and University Science Research Project of Jiangsu Province （ 11KJAd30005 ）.
文摘Based on ANSYS FEM software, the distribution of residual stress in the diffusion bonding joints between Ti（ C,N） metallic ceramic/interlayer/4OCr steel was calculated and experimentally ver^ed. The results showed that the trend on the distribution of residual stress field in the joints was not changed with the use of interlayer. The maximum residual stress was always located in metallic ceramic with area ranging from 1 mm to 4 mm to the interlayer. The maximum residual stress in the joints was also affected by diffusion temperature. The satellite pulse current during the initial stage on diffusion bonding can promote the formation of liquid film at the interface, by which diffusion temperature and loading pressure can be greatly decreased. The crack initiation was easily produced at the corner of Ti （ C, N） metallic ceramic close to the interlayer. If a higher residual stress produced in the joints, the crack was propagated into the whole ceramic.
文摘Fe-based alloy coatings reinforced by Ti（ C, N） particles was produced through CO2 laser cladding technology. The microstructure of laser cladding coating was analyzed by means of X-ray diffraction （ XRD ）, transmission electron microscopy （TEM） , selected area electron diffraction （ SAED ） , scanning electron microscopy （SEM） and electron probe microscopic analyzer （ EPMA ）. The mechanical property of the layer was measured by using microhardness meter. The results show that Ti （ C0. 3 N0. 7 ） panicles are introduced by an in-situ metallurgical reaction between TiN particle and graphite powder during laser cladding process. Titanium carbonitrides particles existed in the layer are fairly fine, ranging from 0. 1 μm to 5.0 μm, and evenly dispersed in the metal α-Fe matrix. Most of them take on nearly rhombus shape, and some of them are irregular in shape. The microhardness of laser cladding layer ranges from 770 HV0. 3 to 850 HV0. 3.
基金This study was supported by the National Natural Science Foundation of China(31960306).
文摘To study non-structural carbohydrate character-istics and nutrient utilization strategies of Pinus yunnanen-sis under continuous drought conditions,2-year-old seed-lings were planted in pots with appropriate water,light and moderate and severe drought treatments[(80±5),(65±5),(50±5),and(35±5)%of field water-holding capacity].Non-structural carbohydrates,carbon(C),nitrogen(N),and phosphorus(P)concentrations were measured in each plant component.The results show that:(1)With increasing drought,non-structural carbohydrates gradually increased in leaves,stems,and coarse roots,while gradually decreased in fine roots;(2)C concentrations of all were relatively stable under different stress levels.Phosphorous utilization of each component increased under light and moderate drought conditions,while N and P utilization efficiency of each plant component decreased under severe drought.Growth was mainly restricted by N,first decreasing and then increasing with increased drought;(3)There was a correlation between the levels of non-structural carbohydrates and C,N,and P in each component.Changes in N concentration affected the interconversion between soluble sugar and starch,which play a regulatory role in the fluctuation of the concentration of non-structural carbohydrates;and,(4)Plasticity analysis showed that P.yunnanensis seedlings responded to drought mainly by altering starch concentration,the ratio of soluble sugar to starch in leaves and stems,and further by alter-ing N and P utilization efficiencies.Overall,these results suggest that the physiological activities of all organs of P.yunnanensis seedlings are restricted under drought and that trade-offs exist between different physiological indicators and organs.Our findings are helpful in understanding non-structural carbohydrate and nutrient adaptation mechanisms under drought in P.yunnanensis seedlings.
