Surfaces of grade III fly ashes were modified through mixing with carbide slag and calcining at 850 ℃ for 1 h. Mineralogical compositions and surface morphology of fly ashes before and after modification were charact...Surfaces of grade III fly ashes were modified through mixing with carbide slag and calcining at 850 ℃ for 1 h. Mineralogical compositions and surface morphology of fly ashes before and after modification were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）, respectively. Effect of surface-modified fly ashes on compressive strength and autogenous shrinkage of blended cement pastes was investigated. Microstructures of cement pastes were examined by backscattered electron （BSE） imaging and mercury intrusion porosimetry （MIP）. The experimental results showed that β-C2S was formed on the surfaces of fly ashes after modification. Hydration ofβ-C2S on the surface-modified fly ashes densified interface zone and enhanced bond strength between particles of fly ashes and hydrated clinkers. In addition, surface modification of fly ashes tended to decrease total porosity and 10-50 nm pores of cement pastes. Surface modification of fly ashes increased compressive strength and reduced autogenous shrinkage of cement pastes.展开更多
Autogenous arteriovenous fistula(AVF)is a lifeline for maintenance hemodialysis patients.In 2006,the vascular access guidelines issued by the Kidney Disease Outcomes Quality Initiative(KDOQI)introduced the concept of...Autogenous arteriovenous fistula(AVF)is a lifeline for maintenance hemodialysis patients.In 2006,the vascular access guidelines issued by the Kidney Disease Outcomes Quality Initiative(KDOQI)introduced the concept of“Fistula first”.1 In 2019,the same organization updated these vascular access guidelines and proposed the concept of“Patient first”,2 sparking a wide range of controversy and discussion on whether to abandon the“Fistula first”principle.Given this context,experts from across China mainland conducted a comprehensive and systematic evaluation of the relevant literature,evidence-based medical guidelines,and international guidelines.展开更多
The relationship between autogenous deformation and internal relative humidity（IRH） of high-strength concrete and high-strength expansive concrete were investigated.The experimental results indicate that,there exist...The relationship between autogenous deformation and internal relative humidity（IRH） of high-strength concrete and high-strength expansive concrete were investigated.The experimental results indicate that,there exists a good linear relationship between autogenous shrinkage and IRH of high-strength concrete but a nonlinear relationship between autogenous deformation and IRH of high-strength expansive concrete with expansive agent.The new autogenous deformation curve can be obtained by transforming the autogenous deformation data of high-strength expansive concrete,and there exists linear relationship between the autogenous deformation and IRH.The concept of ＂critical internal relative humidity＂ was proposed,which is defined as the value of IRH when autogenous deformation is zero,to effectively reflect the autogenous deformation characteristic of expansive concrete.展开更多
Effects of water to binder ratio (m(W)/m(B)), types and addition content of mineral admixtures ont he autogenous relative humidity (ARH) change of concrete resulting from self-desiccation were studies. The parameters ...Effects of water to binder ratio (m(W)/m(B)), types and addition content of mineral admixtures ont he autogenous relative humidity (ARH) change of concrete resulting from self-desiccation were studies. The parameters of coefficient of mineral self-desiccation-effect ka nd efficient water to binder ratio r(e) were proposed, and experimental results were fitted non-linearly and analyzed using these proposed parameters. The experimental results indicate that ARH reduction of concrete at different ages increases with the decrease of m(W)/m(B). The ARH changes laws of concrete with m(W)/m(B) lower than 0.4 can be expressed with a non-linear equation. The extent of the effect of types and addition content of mineral admixures on ARH reduction of concrete resulting from self-desiccation can be reflected by the non-linear equation with the parameter of efficient water to binder ratio r(e) effectively.展开更多
Repair and reconstruction of large bone defect were often difficult,and bone substitute materials,including autogenous bone,allogenic bone and artificial bone,were common treatment strategies.The key to elucidate the ...Repair and reconstruction of large bone defect were often difficult,and bone substitute materials,including autogenous bone,allogenic bone and artificial bone,were common treatment strategies.The key to elucidate the clinical effect of these bone repair materials was to study their osteogenic capacity and immunotoxicological compatibility.In this paper,the mechanical properties,micro-CT imaging analysis,digital image analysis and histological slice analysis of the three bone grafts were investigated and compared after different time points of implantation in rat femur defect model.Autogenous bone and biphasic calcium phosphate particular artificial bone containing 61.4% HA and 38.6%β-tricalcium phosphate with 61.64%porosity and 0.8617±0.0068 g/cm^(3) den-sity(d≤2 mm)had similar and strong bone repair ability,but autogenous bone implant materials caused greater secondary damage to experimental animals;allogenic bone exhibited poor bone defect repair ability.At the early stage of implantation,the immunological indexes such as Immunoglobulin G,Immunoglobulin M concentration and CD4 cells'population of allogenic bone significantly increased in compared with those of autologous bone and artificial bone.Although the repair process of artificial bone was relatively inefficient than autologous bone graft,the low immunotoxicological indexes and acceptable therapeutic effects endowed it as an excellent alter-native material to solve the problems with insufficient source and secondary trauma of autogenous bone.展开更多
This research indicates that the gradient of internal relative humidity （IRH） decreases rapidly within 7-day curing age in HPC. The amount of water imported by pre-wetted light-weight aggregate can regulate IRH of ...This research indicates that the gradient of internal relative humidity （IRH） decreases rapidly within 7-day curing age in HPC. The amount of water imported by pre-wetted light-weight aggregate can regulate IRH of concrete. By importing a proper amount of water, the process of the decline of IRH can be delayed and the autogenous shrinkage can be reduced. The relationship among the amount of water imported by pre- wetted lightweight aggregate, IRH and AS was established. The result provides a new method of reducing early AS and enhancing early cracking resistance of HPC.展开更多
基金Funded by the National Basic Research Program of China (No.2009CB623105)
文摘Surfaces of grade III fly ashes were modified through mixing with carbide slag and calcining at 850 ℃ for 1 h. Mineralogical compositions and surface morphology of fly ashes before and after modification were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）, respectively. Effect of surface-modified fly ashes on compressive strength and autogenous shrinkage of blended cement pastes was investigated. Microstructures of cement pastes were examined by backscattered electron （BSE） imaging and mercury intrusion porosimetry （MIP）. The experimental results showed that β-C2S was formed on the surfaces of fly ashes after modification. Hydration ofβ-C2S on the surface-modified fly ashes densified interface zone and enhanced bond strength between particles of fly ashes and hydrated clinkers. In addition, surface modification of fly ashes tended to decrease total porosity and 10-50 nm pores of cement pastes. Surface modification of fly ashes increased compressive strength and reduced autogenous shrinkage of cement pastes.
文摘Autogenous arteriovenous fistula(AVF)is a lifeline for maintenance hemodialysis patients.In 2006,the vascular access guidelines issued by the Kidney Disease Outcomes Quality Initiative(KDOQI)introduced the concept of“Fistula first”.1 In 2019,the same organization updated these vascular access guidelines and proposed the concept of“Patient first”,2 sparking a wide range of controversy and discussion on whether to abandon the“Fistula first”principle.Given this context,experts from across China mainland conducted a comprehensive and systematic evaluation of the relevant literature,evidence-based medical guidelines,and international guidelines.
基金Funded by National Natural Science Foundation of china (No. 50508034)Guangxi Key Laboratory for the Advanced Materials and New Preparation Technology(No. 063006-5C-13)China,and National Basic Research Programof China(No.2009CB623201)
文摘The relationship between autogenous deformation and internal relative humidity（IRH） of high-strength concrete and high-strength expansive concrete were investigated.The experimental results indicate that,there exists a good linear relationship between autogenous shrinkage and IRH of high-strength concrete but a nonlinear relationship between autogenous deformation and IRH of high-strength expansive concrete with expansive agent.The new autogenous deformation curve can be obtained by transforming the autogenous deformation data of high-strength expansive concrete,and there exists linear relationship between the autogenous deformation and IRH.The concept of ＂critical internal relative humidity＂ was proposed,which is defined as the value of IRH when autogenous deformation is zero,to effectively reflect the autogenous deformation characteristic of expansive concrete.
文摘Effects of water to binder ratio (m(W)/m(B)), types and addition content of mineral admixtures ont he autogenous relative humidity (ARH) change of concrete resulting from self-desiccation were studies. The parameters of coefficient of mineral self-desiccation-effect ka nd efficient water to binder ratio r(e) were proposed, and experimental results were fitted non-linearly and analyzed using these proposed parameters. The experimental results indicate that ARH reduction of concrete at different ages increases with the decrease of m(W)/m(B). The ARH changes laws of concrete with m(W)/m(B) lower than 0.4 can be expressed with a non-linear equation. The extent of the effect of types and addition content of mineral admixures on ARH reduction of concrete resulting from self-desiccation can be reflected by the non-linear equation with the parameter of efficient water to binder ratio r(e) effectively.
基金This work was supported by National Key Research and Development Program of China(2018YFC1106800)Sichuan province key research and development project(20ZDYF0191).
文摘Repair and reconstruction of large bone defect were often difficult,and bone substitute materials,including autogenous bone,allogenic bone and artificial bone,were common treatment strategies.The key to elucidate the clinical effect of these bone repair materials was to study their osteogenic capacity and immunotoxicological compatibility.In this paper,the mechanical properties,micro-CT imaging analysis,digital image analysis and histological slice analysis of the three bone grafts were investigated and compared after different time points of implantation in rat femur defect model.Autogenous bone and biphasic calcium phosphate particular artificial bone containing 61.4% HA and 38.6%β-tricalcium phosphate with 61.64%porosity and 0.8617±0.0068 g/cm^(3) den-sity(d≤2 mm)had similar and strong bone repair ability,but autogenous bone implant materials caused greater secondary damage to experimental animals;allogenic bone exhibited poor bone defect repair ability.At the early stage of implantation,the immunological indexes such as Immunoglobulin G,Immunoglobulin M concentration and CD4 cells'population of allogenic bone significantly increased in compared with those of autologous bone and artificial bone.Although the repair process of artificial bone was relatively inefficient than autologous bone graft,the low immunotoxicological indexes and acceptable therapeutic effects endowed it as an excellent alter-native material to solve the problems with insufficient source and secondary trauma of autogenous bone.
文摘This research indicates that the gradient of internal relative humidity （IRH） decreases rapidly within 7-day curing age in HPC. The amount of water imported by pre-wetted light-weight aggregate can regulate IRH of concrete. By importing a proper amount of water, the process of the decline of IRH can be delayed and the autogenous shrinkage can be reduced. The relationship among the amount of water imported by pre- wetted lightweight aggregate, IRH and AS was established. The result provides a new method of reducing early AS and enhancing early cracking resistance of HPC.
