The process of dislocation multiplication has been described hv chaos theory, trying to reveal the connection between the microstructures on the mesoscopic scale and the mechanical properties of material on the macros...The process of dislocation multiplication has been described hv chaos theory, trying to reveal the connection between the microstructures on the mesoscopic scale and the mechanical properties of material on the macroscopic scale. The relationship between the dislocation velocity exponent and the maximum of strain rate is given. The results obtained from logistic equation with exponent and the dislocation multiplication dynamic equation are compared. A scale law in one-dimension-map model with exponent is shown when the exponents of equations are changed.展开更多
On October 27, 2001, a large earthquake with M S6.0, named the Yongsheng earthquake, occurred along the Jinshajiang segment of Chenghai fault in Yongsheng County, Yunnan Province. It is the largest event to occur alon...On October 27, 2001, a large earthquake with M S6.0, named the Yongsheng earthquake, occurred along the Jinshajiang segment of Chenghai fault in Yongsheng County, Yunnan Province. It is the largest event to occur along the Chenghai fault in the last 200 years. The seismo-geological survey shows that the seismogenic fault, which is the Jinshajiang segment of Chenghai fault, takes left-lateral strike-slip as its dominant movement pattern. According to differences in vertical motion, motion time, landforms and scales, the Chenhai fault can be divided into eight segments. The Jinshajiang segment has a vertical dislocation rate of 0.4 mm/a, far lower than the mean rate of the Chenghai fault, about 2.0 mm/a. It’s deduced that the two sides of Jinshajiang segment “stuck" tightly and hindered the strike-slip of the Chenghai fault. The strong earthquake distribution before this event shows that the Jinshajiang segment was in the seismic gap. The Chenghai fault, as a boundary of tectonic sub-blocks, makes the Northwest Yunnan block and the Middle Yunnan block move clockwise, and their margins move oppositely along the Chenghai fault. In the motion process of the Chenghai fault, structural hindrance and the seismic gap of strong earthquakes are propitious to the concentration and accumulation of structure stress. As a result, the Yongsheng M S6.0 earthquake occurred. The Sujiazhuang-Shangangfu segment is similar to the Jinshajiang segment with a low vertical motion rate of 0.3 mm/a and in the seismic gap. So it’s postulated that the segment may become a new structure hindrance, and the Yongsheng M S6.0 earthquake may trigger the occurrence of future large earthquakes along this segment.展开更多
The γ/γ＇ microstructural evolution in a nickel based single crystal superalloy during load-free thermal exposure at 900 ℃ has been further investigated in this paper. The growth characteristics of γ＇ precipitate...The γ/γ＇ microstructural evolution in a nickel based single crystal superalloy during load-free thermal exposure at 900 ℃ has been further investigated in this paper. The growth characteristics of γ＇ precipitates were discussed in detail. The generation of interfacial dislocations would accelerate the rate of coalescence in the dendrite arms. The average sizes of precipitates were used to compare interface with diffusion controlled growth mechanism and no mechanism seems obviously dominant, although the square rate law gives slightly better fit. The coarsening behavior may be controlled by diffusion through the ragged interface between the γ＇ precipitate and the y matrix.展开更多
Purpose Over 30,000 hip hemiarthroplasties for neck of femur fractures are performed annually in the United Kingdom(UK).The national recommendation is via the lateral approach,to reduce the risk of dislocation,with th...Purpose Over 30,000 hip hemiarthroplasties for neck of femur fractures are performed annually in the United Kingdom(UK).The national recommendation is via the lateral approach,to reduce the risk of dislocation,with the potential expense of reduced function and mobility post-operatively.Muscle-sparing approaches,such as SPAIRE(sparing piriformis and internus repairing externus),have been invented to address the issue of dislocation.Methods We performed a retrospective data collection at a single center with a high annual volume of hip hemiarthroplasties over 12 months.All patients who had hip hemiarthroplasty as their primary treatment were included.Patients who passed away and were non-ambulant before their surgery were excluded from the study.Our primary outcome was the dislocation rate and secondary outcomes were the time to mobilization after surgery and the duration of surgery.Statistical analysis was performed using XLSTAT software.Results We identified 194 cases,and these were divided into 3 groups based on the surgical approach:SPAIRE(n=43),lateral(n=97),and posterior(n=54).Groups had similar demographics and a minimum 3-month follow-up after surgery.There were no dislocations in the SPAIRE group,whereas the dislocation rate for the other 2 groups was 2.5%in the lateral and 9.1%in the posterior groups at 6 months post-surgery.There was an earlier return to mobility in the SPAIRE(1.4 day)compared to the 2 other groups(2 days and 2.6 days).Average surgical times were very similar among all 3 groups(74 min vs.79 min vs.71 min).Conclusion The SPAIRE approach seems to be safe and provides a low risk of dislocation and good post-operative function for patients undergoing hip hemiarthroplasties.展开更多
基金This work was financially supported by the NationalNatural Science FOundation of China (grant No.5987l056 and No.59831020) an
文摘The process of dislocation multiplication has been described hv chaos theory, trying to reveal the connection between the microstructures on the mesoscopic scale and the mechanical properties of material on the macroscopic scale. The relationship between the dislocation velocity exponent and the maximum of strain rate is given. The results obtained from logistic equation with exponent and the dislocation multiplication dynamic equation are compared. A scale law in one-dimension-map model with exponent is shown when the exponents of equations are changed.
文摘On October 27, 2001, a large earthquake with M S6.0, named the Yongsheng earthquake, occurred along the Jinshajiang segment of Chenghai fault in Yongsheng County, Yunnan Province. It is the largest event to occur along the Chenghai fault in the last 200 years. The seismo-geological survey shows that the seismogenic fault, which is the Jinshajiang segment of Chenghai fault, takes left-lateral strike-slip as its dominant movement pattern. According to differences in vertical motion, motion time, landforms and scales, the Chenhai fault can be divided into eight segments. The Jinshajiang segment has a vertical dislocation rate of 0.4 mm/a, far lower than the mean rate of the Chenghai fault, about 2.0 mm/a. It’s deduced that the two sides of Jinshajiang segment “stuck" tightly and hindered the strike-slip of the Chenghai fault. The strong earthquake distribution before this event shows that the Jinshajiang segment was in the seismic gap. The Chenghai fault, as a boundary of tectonic sub-blocks, makes the Northwest Yunnan block and the Middle Yunnan block move clockwise, and their margins move oppositely along the Chenghai fault. In the motion process of the Chenghai fault, structural hindrance and the seismic gap of strong earthquakes are propitious to the concentration and accumulation of structure stress. As a result, the Yongsheng M S6.0 earthquake occurred. The Sujiazhuang-Shangangfu segment is similar to the Jinshajiang segment with a low vertical motion rate of 0.3 mm/a and in the seismic gap. So it’s postulated that the segment may become a new structure hindrance, and the Yongsheng M S6.0 earthquake may trigger the occurrence of future large earthquakes along this segment.
文摘The γ/γ＇ microstructural evolution in a nickel based single crystal superalloy during load-free thermal exposure at 900 ℃ has been further investigated in this paper. The growth characteristics of γ＇ precipitates were discussed in detail. The generation of interfacial dislocations would accelerate the rate of coalescence in the dendrite arms. The average sizes of precipitates were used to compare interface with diffusion controlled growth mechanism and no mechanism seems obviously dominant, although the square rate law gives slightly better fit. The coarsening behavior may be controlled by diffusion through the ragged interface between the γ＇ precipitate and the y matrix.
文摘Purpose Over 30,000 hip hemiarthroplasties for neck of femur fractures are performed annually in the United Kingdom(UK).The national recommendation is via the lateral approach,to reduce the risk of dislocation,with the potential expense of reduced function and mobility post-operatively.Muscle-sparing approaches,such as SPAIRE(sparing piriformis and internus repairing externus),have been invented to address the issue of dislocation.Methods We performed a retrospective data collection at a single center with a high annual volume of hip hemiarthroplasties over 12 months.All patients who had hip hemiarthroplasty as their primary treatment were included.Patients who passed away and were non-ambulant before their surgery were excluded from the study.Our primary outcome was the dislocation rate and secondary outcomes were the time to mobilization after surgery and the duration of surgery.Statistical analysis was performed using XLSTAT software.Results We identified 194 cases,and these were divided into 3 groups based on the surgical approach:SPAIRE(n=43),lateral(n=97),and posterior(n=54).Groups had similar demographics and a minimum 3-month follow-up after surgery.There were no dislocations in the SPAIRE group,whereas the dislocation rate for the other 2 groups was 2.5%in the lateral and 9.1%in the posterior groups at 6 months post-surgery.There was an earlier return to mobility in the SPAIRE(1.4 day)compared to the 2 other groups(2 days and 2.6 days).Average surgical times were very similar among all 3 groups(74 min vs.79 min vs.71 min).Conclusion The SPAIRE approach seems to be safe and provides a low risk of dislocation and good post-operative function for patients undergoing hip hemiarthroplasties.
