Chitosan/nano-hydroxyapatite composites with different weight ratios were prepared through a co-precipitation method using Ca（OH）2, H3PO4 and chitosan as starting materials. The properties of these composites were c...Chitosan/nano-hydroxyapatite composites with different weight ratios were prepared through a co-precipitation method using Ca（OH）2, H3PO4 and chitosan as starting materials. The properties of these composites were characterized by means of TEM, IR, XRD, TGA, burn-out tests and universal matertial testing machine. The results showed that the HA synthesized here was poorly crystalline carbonated nanometer crystals and dispersed uniformly in chitosan phase and there was no phase-separation between the two phases. The addition of n-HA resulted in a decrease of decomposing temperature of chitosan. Because of the interactions between chitosan and n-HA, the mechanical properties of these composites were improved, and the maximum value of the compressive strength was measured to be about 120MPa corresponding to the chitosan/n-HA composite with a weight ratio of 30/70.展开更多
Patients with osteomyelitis require lengthy antibiotic treatment, often only to see the inflammation flare up once antibiotics are suspended. Unfortunately, patients often discontinue the antibiotic treatment due to c...Patients with osteomyelitis require lengthy antibiotic treatment, often only to see the inflammation flare up once antibiotics are suspended. Unfortunately, patients often discontinue the antibiotic treatment due to collateral effects. Patients with osteitis are often polymorbid patients with other severe diseases such as diabetes mellitus and polyneuropathy, arteriopathy or polyarthfitis with immunosuppression. The eight patients included in the study presented nine bones with osteomyelitis （macroscopically, bacteriologically, histologically or radiologically）. The diseased part of the bone was resected, a locally radical debridement was done and a biopsy for bacteriology and histology were taken. The residual bone was then drilled out and filled with antibiotic-loaded （gentamicin） resorbable bone-graft substitute under radiologic imaging control. In total, seven patients are currently without recurrent osteomyelitis with a mean follow-up of 5.77 months （2-11 months）. The Kaplan Meier curve shows 80% survival rate without recurrent osteomyelitis at 11 months. Only one patient suffering from Morbus Buerger had a relapse osteomyelitis after cutting off severing his foot while swimming in the sea. Antibiotic-loaded resorbable bone-graft substitute is easy to use, has in our hands few complications and low recurrence rate.展开更多
The results of experimental works aimed on finding the optimal composition of concretes containing alternative materials as mineral additives for assurance their high resistance to chemical aggressive attack are prese...The results of experimental works aimed on finding the optimal composition of concretes containing alternative materials as mineral additives for assurance their high resistance to chemical aggressive attack are presented in the paper. 4 kinds of additives （blast furnace slag, fly ash, non-treated and treated serpentinite waste） and 4 kinds of aggressive environments （distilled water, HCI, MgSO4 and NaOH） representing the concrete corrosive processes was checked within experimental process. The open laboratory curing was used as a reference environment. Moreover, the amounts of additives were varied, so 16 various recipes were checked on the whole. The resistance of samples was tested in the terms of flexural strength, compressive strength and evaluation of decrease/increase of strengths after long time （28 months） exposition in monitored aggressive media. Based on obtained results, it is possible for each of aggressive environments recommend the most promising recipe from various points of view, in accordance with user＇s priorities. From the percentage increase of 28-day compressive strengths point of view, there are： for HCI action - recipe with 20% of non treated serpentinite waste with plasticizer application, for MgSO4 action - recipe with 20% of blast furnace slag without plasticizer application and for NaOH action - recipe with 10% of non treated serpentinite waste without plasticizer application. Application of alternative materials as partial substitution of cement appears to be beneficial for achievement the resistance to aggressive chemical actions. With the keeping or enhancement of technical parameters it extra represents both the environmental and economic benefit.展开更多
Electrically conductive composite films ofpolyaniline and nylon-6.6 are prepared by diffusing aniline followed by oxidative polymerization of aniline into nylon-6.6 matrix. In order to determine the diffusion coeffici...Electrically conductive composite films ofpolyaniline and nylon-6.6 are prepared by diffusing aniline followed by oxidative polymerization of aniline into nylon-6.6 matrix. In order to determine the diffusion coefficient for the chloride ion diffusion into the composite matrix electrochemically, galvanostatic pulse method is used and the diffusion coefficient is estimated to be -6.48× 10^-17 cm^2s^-1. The results are discussed in view of them being potential replacement materials for battery. electrodes and sensors devices.展开更多
The QUENCH experimental programme at Karlsruhe under severe accident conditions, but while the geometry is still Institute of Technology investigates heat-up and reflooding of a core mainly rod-like. The recent QUENCH...The QUENCH experimental programme at Karlsruhe under severe accident conditions, but while the geometry is still Institute of Technology investigates heat-up and reflooding of a core mainly rod-like. The recent QUENCH-ACM series of experiments, comprising QUENCH-12 （El 10 cladding alloy）, -14 （M5 alloy） and -15 （Zirlo^TM alloy）, together with QUENCH-06 （reference case, Zircaloy-4 alloy） addressed the effect of alternative cladding materials on oxidation and quenching under similar conditions. Superficial inspection of the experimental results reveals only minor differences in the thermal and oxidation response, except for the much larger hydrogen release during reflood in QUENCH-12. Post-test calculations were performed using a version of SCDAP/RELAP5/MOD3.2, modified to represent the QUENCH facility and to invoke alternative oxidation correlations. The calculations agreed rather well with experiments QUENCH-06, -14 and -15, but the significant hydrogen release during reflood in QUENCH-12 was not captured. Closer examination of the experimental results reveals further differences between QUENCH-12 which may be linked to breakaway oxidation of the E110 cladding. The analyses support the heuristic observation that there was no major difference between the influence of Zircaloy-4, M5 or ZirloTM, but the E-110 exhibited a contrasting behaviour with a consequent impact on the reflooding.展开更多
The objective of this study was to investigate the hemocompatibility and cell responses to some novel poly（L-lactide） （PLA） composites containing surface modified hydroxyapatite particles for potential application...The objective of this study was to investigate the hemocompatibility and cell responses to some novel poly（L-lactide） （PLA） composites containing surface modified hydroxyapatite particles for potential applications as a bone substitute material. The surface of hydroxyapatite （HA） particles was first grafted with L-lactic acid oligomers to form grafted HA （g-HA） particles. The g-HA particles were further blended with PLA to prepare g-HA/PLA composites. Our previous study has shown signifi- cant improvement in tensile properties of these materials due to the enhanced interracial adhesion between the polymer matrix and HA particles. To further investigate the potential applications of these composites in bone repair and other orthopedic sur- geries, a series of in vitro and in vivo experiments were conducted to examine the cell responses and hemocompatibility of the materials. In vitro experiments showed that the g-HA/PLA composites were well tolerated by the L-929 cells. Hemolysis of the composites was lower than that of pure PLA. Subcutaneous implantation demonstrated that the g-HA/PLA composites were more favorable than the control materials for soft tissue responses. The results suggested that the g-HA/PLA composites are promising and safe materials with potential applications in tissue engineering.展开更多
The design concept of high excess pressure cockpit has been proposed as a solution to solve the ergonomics problems caused by cockpit environment.To address the contradiction among mass,economy,maneuverability and env...The design concept of high excess pressure cockpit has been proposed as a solution to solve the ergonomics problems caused by cockpit environment.To address the contradiction among mass,economy,maneuverability and environment ergonomics,considering the composite advantages of high strength and lightweight,the feasibility analysis concept of high excess pressure cockpit based on material substitution is proposed in the paper.Based on the strain energy analysis on finite element model,the iteration design method of equal stiffness and lightening effect analysis on material substitution are presented,The weight reduction effect after material substitution can be evaluated intuitively by using equal stiffness curve.The calculation result of cockpit indicates that the lightening effect can reach 35.09%.Because of the complexity of cockpit design,bi-level optimization method is proposed and performed by means of the First-Order Radio algorithm.The research shows that the method can achieve good result.The feasibility of high excess pressure cockpit is studied from the aspect of the relationship between excess pressure and mass,and the research demonstrates that,due to the utilization of T300/4211 in place of 6061 alloy,the excess pressure of cockpit increases from 35 to 45 kPa,a 28.57%increase,while the cockpit mass is decreased by 12.56%.Thus,the contradiction among mass,economy and environment ergonomics can be coordinated,which can provide a reference for the design of high excess pressure cockpit.展开更多
文摘Chitosan/nano-hydroxyapatite composites with different weight ratios were prepared through a co-precipitation method using Ca（OH）2, H3PO4 and chitosan as starting materials. The properties of these composites were characterized by means of TEM, IR, XRD, TGA, burn-out tests and universal matertial testing machine. The results showed that the HA synthesized here was poorly crystalline carbonated nanometer crystals and dispersed uniformly in chitosan phase and there was no phase-separation between the two phases. The addition of n-HA resulted in a decrease of decomposing temperature of chitosan. Because of the interactions between chitosan and n-HA, the mechanical properties of these composites were improved, and the maximum value of the compressive strength was measured to be about 120MPa corresponding to the chitosan/n-HA composite with a weight ratio of 30/70.
文摘Patients with osteomyelitis require lengthy antibiotic treatment, often only to see the inflammation flare up once antibiotics are suspended. Unfortunately, patients often discontinue the antibiotic treatment due to collateral effects. Patients with osteitis are often polymorbid patients with other severe diseases such as diabetes mellitus and polyneuropathy, arteriopathy or polyarthfitis with immunosuppression. The eight patients included in the study presented nine bones with osteomyelitis （macroscopically, bacteriologically, histologically or radiologically）. The diseased part of the bone was resected, a locally radical debridement was done and a biopsy for bacteriology and histology were taken. The residual bone was then drilled out and filled with antibiotic-loaded （gentamicin） resorbable bone-graft substitute under radiologic imaging control. In total, seven patients are currently without recurrent osteomyelitis with a mean follow-up of 5.77 months （2-11 months）. The Kaplan Meier curve shows 80% survival rate without recurrent osteomyelitis at 11 months. Only one patient suffering from Morbus Buerger had a relapse osteomyelitis after cutting off severing his foot while swimming in the sea. Antibiotic-loaded resorbable bone-graft substitute is easy to use, has in our hands few complications and low recurrence rate.
文摘The results of experimental works aimed on finding the optimal composition of concretes containing alternative materials as mineral additives for assurance their high resistance to chemical aggressive attack are presented in the paper. 4 kinds of additives （blast furnace slag, fly ash, non-treated and treated serpentinite waste） and 4 kinds of aggressive environments （distilled water, HCI, MgSO4 and NaOH） representing the concrete corrosive processes was checked within experimental process. The open laboratory curing was used as a reference environment. Moreover, the amounts of additives were varied, so 16 various recipes were checked on the whole. The resistance of samples was tested in the terms of flexural strength, compressive strength and evaluation of decrease/increase of strengths after long time （28 months） exposition in monitored aggressive media. Based on obtained results, it is possible for each of aggressive environments recommend the most promising recipe from various points of view, in accordance with user＇s priorities. From the percentage increase of 28-day compressive strengths point of view, there are： for HCI action - recipe with 20% of non treated serpentinite waste with plasticizer application, for MgSO4 action - recipe with 20% of blast furnace slag without plasticizer application and for NaOH action - recipe with 10% of non treated serpentinite waste without plasticizer application. Application of alternative materials as partial substitution of cement appears to be beneficial for achievement the resistance to aggressive chemical actions. With the keeping or enhancement of technical parameters it extra represents both the environmental and economic benefit.
文摘Electrically conductive composite films ofpolyaniline and nylon-6.6 are prepared by diffusing aniline followed by oxidative polymerization of aniline into nylon-6.6 matrix. In order to determine the diffusion coefficient for the chloride ion diffusion into the composite matrix electrochemically, galvanostatic pulse method is used and the diffusion coefficient is estimated to be -6.48× 10^-17 cm^2s^-1. The results are discussed in view of them being potential replacement materials for battery. electrodes and sensors devices.
文摘The QUENCH experimental programme at Karlsruhe under severe accident conditions, but while the geometry is still Institute of Technology investigates heat-up and reflooding of a core mainly rod-like. The recent QUENCH-ACM series of experiments, comprising QUENCH-12 （El 10 cladding alloy）, -14 （M5 alloy） and -15 （Zirlo^TM alloy）, together with QUENCH-06 （reference case, Zircaloy-4 alloy） addressed the effect of alternative cladding materials on oxidation and quenching under similar conditions. Superficial inspection of the experimental results reveals only minor differences in the thermal and oxidation response, except for the much larger hydrogen release during reflood in QUENCH-12. Post-test calculations were performed using a version of SCDAP/RELAP5/MOD3.2, modified to represent the QUENCH facility and to invoke alternative oxidation correlations. The calculations agreed rather well with experiments QUENCH-06, -14 and -15, but the significant hydrogen release during reflood in QUENCH-12 was not captured. Closer examination of the experimental results reveals further differences between QUENCH-12 which may be linked to breakaway oxidation of the E110 cladding. The analyses support the heuristic observation that there was no major difference between the influence of Zircaloy-4, M5 or ZirloTM, but the E-110 exhibited a contrasting behaviour with a consequent impact on the reflooding.
基金supported by the Research Fund for the Doctoral Program of Higher Education(Grant No.20060217012)
文摘The objective of this study was to investigate the hemocompatibility and cell responses to some novel poly（L-lactide） （PLA） composites containing surface modified hydroxyapatite particles for potential applications as a bone substitute material. The surface of hydroxyapatite （HA） particles was first grafted with L-lactic acid oligomers to form grafted HA （g-HA） particles. The g-HA particles were further blended with PLA to prepare g-HA/PLA composites. Our previous study has shown signifi- cant improvement in tensile properties of these materials due to the enhanced interracial adhesion between the polymer matrix and HA particles. To further investigate the potential applications of these composites in bone repair and other orthopedic sur- geries, a series of in vitro and in vivo experiments were conducted to examine the cell responses and hemocompatibility of the materials. In vitro experiments showed that the g-HA/PLA composites were well tolerated by the L-929 cells. Hemolysis of the composites was lower than that of pure PLA. Subcutaneous implantation demonstrated that the g-HA/PLA composites were more favorable than the control materials for soft tissue responses. The results suggested that the g-HA/PLA composites are promising and safe materials with potential applications in tissue engineering.
文摘The design concept of high excess pressure cockpit has been proposed as a solution to solve the ergonomics problems caused by cockpit environment.To address the contradiction among mass,economy,maneuverability and environment ergonomics,considering the composite advantages of high strength and lightweight,the feasibility analysis concept of high excess pressure cockpit based on material substitution is proposed in the paper.Based on the strain energy analysis on finite element model,the iteration design method of equal stiffness and lightening effect analysis on material substitution are presented,The weight reduction effect after material substitution can be evaluated intuitively by using equal stiffness curve.The calculation result of cockpit indicates that the lightening effect can reach 35.09%.Because of the complexity of cockpit design,bi-level optimization method is proposed and performed by means of the First-Order Radio algorithm.The research shows that the method can achieve good result.The feasibility of high excess pressure cockpit is studied from the aspect of the relationship between excess pressure and mass,and the research demonstrates that,due to the utilization of T300/4211 in place of 6061 alloy,the excess pressure of cockpit increases from 35 to 45 kPa,a 28.57%increase,while the cockpit mass is decreased by 12.56%.Thus,the contradiction among mass,economy and environment ergonomics can be coordinated,which can provide a reference for the design of high excess pressure cockpit.
