According to the characteristics of thin-layer rolling and pouting construction technology and the complicated mechanical behavior of the roller compacted concrete dam （RCCD） construction interface, a constitutive m...According to the characteristics of thin-layer rolling and pouting construction technology and the complicated mechanical behavior of the roller compacted concrete dam （RCCD） construction interface, a constitutive model of endochronic damage was established based on the endochronic theory and damage mechanics. The proposed model abandons the traditional concept of elastic-plastic yield surface and can better reflect the real behavior of rolled control concrete. Basic equations were proposed for the fluid-solid coupling analysis, and the relationships among the corresponding key physical parameters were also put forward. One three-dimensional finite element method （FEM） program was obtained by studying the FEM type of the seepage-stress coupling intersection of the RCCD. The method was applied to an actual project, and the results show that the fluid-solid interaction influences dam deformation and dam abutment stability, which is in accordance with practice. Therefore, this model provides a new method for revealing the mechanical behavior of RCCD under the coupling field.展开更多
Objective：To elucidate the relationship between surgical time and postoperative complications in senile patients with hip fractures, and try to find out other factors which are related to these complications.Methods...Objective：To elucidate the relationship between surgical time and postoperative complications in senile patients with hip fractures, and try to find out other factors which are related to these complications.Methods： Sixty-two patients, 28 males aged from 65 to 72 years with a mean age of 76.3 years and 34 females aged from 65 to 95 years with a mean age of 78.1 years, who had undergone orthopedic surgery because of hip fractures,were enrolled in a retrospective cohort study. The surgical time and pattern, the type of fracture, preoperative comorbidities, American Society of Anesthesiologists （ASA） score and the volume of blood transfusion during operation were obtained from these patients who were followed up by telephone calls for postoperative complications.All the patients were followed up at least for 1 year and were divided into subgroups according to their clinical characteristics and the results were analyzed by the Statistical Analysis System software.Results：There was no significant difference in the morbidity of postoperative eomplications with the gender,age,surgical time and pattern,or ASA score. There was significant difference in the morbidity of postoperative complications related to preoperative comorbidities and the volume of blood transfusion. There was a significant causality between preoperative comorbidities and postoperative complications. The morbidity of postoperative complications was 1.651 times higher in patients with preoperative comorbidities than those without.Conclusions：There is no relationship between the surgical time and postoperative complications in senile patients who received surgery for hip fracture within 1 year.No correlation is found between the postoperative complications and gender,age,type of fracture, surgical pattern,ASA score and the volume of blood transfusion. Preoperative comorbidities are an independent predictor for postoperative complications.展开更多
基金Projects(51139001,51179066,51079046,50909041) supported by the National Natural Science Foundation of ChinaProject(NCET-10-0359) supported by the Program for New Century Excellent Talents in UniversityProjects(2009586012,2009586912,2010585212)supported by the Special Fund of State Key Laboratory of China
文摘According to the characteristics of thin-layer rolling and pouting construction technology and the complicated mechanical behavior of the roller compacted concrete dam （RCCD） construction interface, a constitutive model of endochronic damage was established based on the endochronic theory and damage mechanics. The proposed model abandons the traditional concept of elastic-plastic yield surface and can better reflect the real behavior of rolled control concrete. Basic equations were proposed for the fluid-solid coupling analysis, and the relationships among the corresponding key physical parameters were also put forward. One three-dimensional finite element method （FEM） program was obtained by studying the FEM type of the seepage-stress coupling intersection of the RCCD. The method was applied to an actual project, and the results show that the fluid-solid interaction influences dam deformation and dam abutment stability, which is in accordance with practice. Therefore, this model provides a new method for revealing the mechanical behavior of RCCD under the coupling field.
基金This study was supported by a grant from the Specially-assigned Scientific Research Project of Central Health Protection Committee （No. 170） and the National Natural Science Foundation of China （No. 10872078 and 10832012）.
文摘Objective：To elucidate the relationship between surgical time and postoperative complications in senile patients with hip fractures, and try to find out other factors which are related to these complications.Methods： Sixty-two patients, 28 males aged from 65 to 72 years with a mean age of 76.3 years and 34 females aged from 65 to 95 years with a mean age of 78.1 years, who had undergone orthopedic surgery because of hip fractures,were enrolled in a retrospective cohort study. The surgical time and pattern, the type of fracture, preoperative comorbidities, American Society of Anesthesiologists （ASA） score and the volume of blood transfusion during operation were obtained from these patients who were followed up by telephone calls for postoperative complications.All the patients were followed up at least for 1 year and were divided into subgroups according to their clinical characteristics and the results were analyzed by the Statistical Analysis System software.Results：There was no significant difference in the morbidity of postoperative eomplications with the gender,age,surgical time and pattern,or ASA score. There was significant difference in the morbidity of postoperative complications related to preoperative comorbidities and the volume of blood transfusion. There was a significant causality between preoperative comorbidities and postoperative complications. The morbidity of postoperative complications was 1.651 times higher in patients with preoperative comorbidities than those without.Conclusions：There is no relationship between the surgical time and postoperative complications in senile patients who received surgery for hip fracture within 1 year.No correlation is found between the postoperative complications and gender,age,type of fracture, surgical pattern,ASA score and the volume of blood transfusion. Preoperative comorbidities are an independent predictor for postoperative complications.
