Spherical Sb-doped SnO2 （ATO） nanoparticles were synthesized by the sol-gel route, employing SnCl4.5H2O and SbCl3 as precursors in an ethanol solution. The influences of the calcining temperature and calcining time ...Spherical Sb-doped SnO2 （ATO） nanoparticles were synthesized by the sol-gel route, employing SnCl4.5H2O and SbCl3 as precursors in an ethanol solution. The influences of the calcining temperature and calcining time on the crystallite size, crystallinity, lattice parameters, lattice distortion ratio and the resistivity of the ATO nanoparticles were synthetically investigated. The results suggested that the ATO nanoparticles were crystallized in a tetragonal cassiterite structure of SnO2 with a highly （110）- plane-preferred orientation. The calcining temperature had a dominating effect on the crystallite size, crystallinity, lattice distortion ratios and resistivity of the ATO. As the calcining temperature increased, the average crystallite size increased, the crystallinity was promoted accompanied by a decrease in the lattice distortion ratio and a corresponding decrease in the resistivity of the ATO. X-ray diffraction （XRD） and Fourier transform infrared spectrophotometer （FTIR） analysis revealed that Sb ions could not entirely supplant the Sn ions in the SnO2 lattice for a calcining time of less than 0.5 h, even at a calcining temperature of 1000 ℃. The ATO nanoparticles calcined at 1000 ℃ for 3,0 h possessed the lowest resistivity of 10.18 Ωcm.展开更多
In this study,the effects of in vivo(head flexion-extension,lateral bending,and axial rotation)and in vitro(ISO 18192-1)working conditions on the wear of ultrahigh mo-lecular weight polyethylene(UHWMPE)-based cervical...In this study,the effects of in vivo(head flexion-extension,lateral bending,and axial rotation)and in vitro(ISO 18192-1)working conditions on the wear of ultrahigh mo-lecular weight polyethylene(UHWMPE)-based cervical disc prosthesis were studied via numerical simulation.A finite-element-based wear prediction framework was built by using a sliding distance and contact area dependent Archard wear law.Moreover,a pre-developed cervical spine multi-body dynamics model was incorporated to obtain the in vivo conditions.Contact mechanic analysis stated that in vitro conditions normally led to a higher contact stress and a longer sliding distance,with oval or crossing-path-typed sliding track.In contrast,in vivo conditions led to a curvilinear-typed sliding track.In general,the predicted in vivo wear rate was one order of magnitude smaller than that of in vitro.According to the yearly occurrence of head movement,the estimated total in vivo wear rate was 0.595 mg/annual.While,the wear rate given by the ISO standard test condition was 3.32 mg/annual.There is a significant impact of loading and kinematic condition on the wear of UHMWPE prosthesis.The work conducted in the present study provided a feasible way for quantitatively assessing the wear of joint prosthesis.展开更多
Excessive wear is a key issue affecting the performance of ultra-high molecular weight polyethylene(UHMWPE)-based artificial prosthesis.This work is focussed on the biotribology behaviours of UHMWPE when mating with d...Excessive wear is a key issue affecting the performance of ultra-high molecular weight polyethylene(UHMWPE)-based artificial prosthesis.This work is focussed on the biotribology behaviours of UHMWPE when mating with different metal counterparts(iron-based 316L,Co-based Stellite-S21 and Stellite-S22).According to the ASTM F732 standard,two million cycles comparative wear tests were carried out under bovine serum lubrication.When coupled with S21,S22,and 316L metal counterparts,the obtained average wear factors of UHMWPE were 1.333±0.192,1.360±0.160,and 1.190±0.177×10^(−6)mm^(3)/N·m,respectively.Initial surface roughness of the metal counterpart has shown an important role in controlling the volume of UHMWPE wear,especially the first one million cycles.Compared with 316L,CoCrMo-based counterparts possessed relative higher hardness and exhibited less rise in surface roughness caused by wear.For UHMWPE-on-metal bearings,random scratch,surface pit,and wear debris attachment were commonly seen,which suggested the coexistence of abrasion,thirdbody abrasion,and adhesion-based wear.In contrast,the metal counterpart was slightly scratched with no polymer transfer film formation.The work conducted in the present study gives useful knowledge regarding the UHMWPE-on-metal bearing design.With an intention to minimise wear,surface roughness of metal counterpart should be carefully controlled.展开更多
基金the National Natural Science Foundation of China (grant no. 50705094)"Hundred Talents Program" of Chinese Academy of Sciences (grant no.KGCX2-YW-804) for providing financial support
文摘Spherical Sb-doped SnO2 （ATO） nanoparticles were synthesized by the sol-gel route, employing SnCl4.5H2O and SbCl3 as precursors in an ethanol solution. The influences of the calcining temperature and calcining time on the crystallite size, crystallinity, lattice parameters, lattice distortion ratio and the resistivity of the ATO nanoparticles were synthetically investigated. The results suggested that the ATO nanoparticles were crystallized in a tetragonal cassiterite structure of SnO2 with a highly （110）- plane-preferred orientation. The calcining temperature had a dominating effect on the crystallite size, crystallinity, lattice distortion ratios and resistivity of the ATO. As the calcining temperature increased, the average crystallite size increased, the crystallinity was promoted accompanied by a decrease in the lattice distortion ratio and a corresponding decrease in the resistivity of the ATO. X-ray diffraction （XRD） and Fourier transform infrared spectrophotometer （FTIR） analysis revealed that Sb ions could not entirely supplant the Sn ions in the SnO2 lattice for a calcining time of less than 0.5 h, even at a calcining temperature of 1000 ℃. The ATO nanoparticles calcined at 1000 ℃ for 3,0 h possessed the lowest resistivity of 10.18 Ωcm.
基金National Natural Science Foundation of China,Grant/Award Number:51675508Natural Science Foundation of Shaanxi Province,China,Grant/Award Number:2020JQ-728。
文摘In this study,the effects of in vivo(head flexion-extension,lateral bending,and axial rotation)and in vitro(ISO 18192-1)working conditions on the wear of ultrahigh mo-lecular weight polyethylene(UHWMPE)-based cervical disc prosthesis were studied via numerical simulation.A finite-element-based wear prediction framework was built by using a sliding distance and contact area dependent Archard wear law.Moreover,a pre-developed cervical spine multi-body dynamics model was incorporated to obtain the in vivo conditions.Contact mechanic analysis stated that in vitro conditions normally led to a higher contact stress and a longer sliding distance,with oval or crossing-path-typed sliding track.In contrast,in vivo conditions led to a curvilinear-typed sliding track.In general,the predicted in vivo wear rate was one order of magnitude smaller than that of in vitro.According to the yearly occurrence of head movement,the estimated total in vivo wear rate was 0.595 mg/annual.While,the wear rate given by the ISO standard test condition was 3.32 mg/annual.There is a significant impact of loading and kinematic condition on the wear of UHMWPE prosthesis.The work conducted in the present study provided a feasible way for quantitatively assessing the wear of joint prosthesis.
基金would like to thank the National Science Foun-dation of Shaanxi Province(grant No.2020JQ-728,2018JQ-5201).
文摘Excessive wear is a key issue affecting the performance of ultra-high molecular weight polyethylene(UHMWPE)-based artificial prosthesis.This work is focussed on the biotribology behaviours of UHMWPE when mating with different metal counterparts(iron-based 316L,Co-based Stellite-S21 and Stellite-S22).According to the ASTM F732 standard,two million cycles comparative wear tests were carried out under bovine serum lubrication.When coupled with S21,S22,and 316L metal counterparts,the obtained average wear factors of UHMWPE were 1.333±0.192,1.360±0.160,and 1.190±0.177×10^(−6)mm^(3)/N·m,respectively.Initial surface roughness of the metal counterpart has shown an important role in controlling the volume of UHMWPE wear,especially the first one million cycles.Compared with 316L,CoCrMo-based counterparts possessed relative higher hardness and exhibited less rise in surface roughness caused by wear.For UHMWPE-on-metal bearings,random scratch,surface pit,and wear debris attachment were commonly seen,which suggested the coexistence of abrasion,thirdbody abrasion,and adhesion-based wear.In contrast,the metal counterpart was slightly scratched with no polymer transfer film formation.The work conducted in the present study gives useful knowledge regarding the UHMWPE-on-metal bearing design.With an intention to minimise wear,surface roughness of metal counterpart should be carefully controlled.
