Here we prepared PEO coatings on Mg alloys in silicate-NaOH-phosphate electrolyte containing different concentrations of NaF addition.The detailed microstructural characterizations combining with potentiodynamic polar...Here we prepared PEO coatings on Mg alloys in silicate-NaOH-phosphate electrolyte containing different concentrations of NaF addition.The detailed microstructural characterizations combining with potentiodynamic polarization and electrochemical impedance spectra(EIS)were employed to investigate the roles of fluoride in the growth and corrosion properties of PEO coating on Mg.The result shows the introduction of NaF led to a fluoride-containing nanolayer(FNL)formed at the Mg/coating interface.The FNL consists of MgO nanoparticles and insoluble MgF_(2)nanoparticles(containing rutile phase and cubic phase).The increase in the NaF concentration of the electrolyte increases the thickness and the MgF_(2)content in the FNL.When anodized in the electrolyte containing 2 g/L NaF,the formed FNL has the highest thickness of 100-200 nm along with the highest value of x of∼0.6 in(MgO)_(1-x)(MgF_(2))x resulted in the highest corrosion performance of PEO coating.In addition,when anodized in the electrolyte containing a low NaF concentration(0.4-0.8 g/L),the formed FNL was thin and discontinuous,which would decrease the pore density and increase the coating's uniformness simultaneously.展开更多
目的:对比Monaco计划系统Per Calculation(PC)和Per Control Point(PCP)两种统计噪声设置方式的剂量计算精度和计算效率。方法:选取30例IMRT/VMAT治疗计划,其中胸部和鼻咽部肿瘤各15例,两种噪声统计方式按照剂量计算精度递减的方式分别...目的:对比Monaco计划系统Per Calculation(PC)和Per Control Point(PCP)两种统计噪声设置方式的剂量计算精度和计算效率。方法:选取30例IMRT/VMAT治疗计划,其中胸部和鼻咽部肿瘤各15例,两种噪声统计方式按照剂量计算精度递减的方式分别设置为5组和6组,评估其对计算时间和各剂量学评价指标的影响。结果:两种噪声统计方式计算时间(s)分别为131.78±26.91、6.76±3.57、1.75±0.57、0.84±0.24、0.84±0.24(PC)和259.20±80.15、73.53±26.00、9.18±3.26、3.60±1.67、1.59±0.75、1.13±0.49(PCP),均与计算精度呈负相关,且差异具有统计学意义(P<0.05);两组计划各剂量学评价指标箱图分析显示,均值和特定剂量的体积等指标四分位距较小,最大值和全局最大值等评价指标四分位距较大;两组计划各剂量学评价指标单因素ANOVA分析结果无统计学差异(P>0.05)。结论:两种统计噪声设置方式均可用于临床治疗计划计算精度设置;治疗计划全局最大值与统计噪声正相关,计算时间与统计噪声负相关;不同PC/PCP参数设置对均值和特定剂量的体积等评价影响较小,对全局和串行器官最大值影响较大。展开更多
基金Zhu.L.and Li.H.contributed equally to this work.This work is supported by the National Natural Science Foundation of China(Grant No.51901121)the Natural Science Foundation of Shaanxi Province(Grant No.2021JM-203,2019JQ-433,2020zdzx04-03-02)the Fundamental Research Funds for the Central Universities(Grant No.GK202103022).
文摘Here we prepared PEO coatings on Mg alloys in silicate-NaOH-phosphate electrolyte containing different concentrations of NaF addition.The detailed microstructural characterizations combining with potentiodynamic polarization and electrochemical impedance spectra(EIS)were employed to investigate the roles of fluoride in the growth and corrosion properties of PEO coating on Mg.The result shows the introduction of NaF led to a fluoride-containing nanolayer(FNL)formed at the Mg/coating interface.The FNL consists of MgO nanoparticles and insoluble MgF_(2)nanoparticles(containing rutile phase and cubic phase).The increase in the NaF concentration of the electrolyte increases the thickness and the MgF_(2)content in the FNL.When anodized in the electrolyte containing 2 g/L NaF,the formed FNL has the highest thickness of 100-200 nm along with the highest value of x of∼0.6 in(MgO)_(1-x)(MgF_(2))x resulted in the highest corrosion performance of PEO coating.In addition,when anodized in the electrolyte containing a low NaF concentration(0.4-0.8 g/L),the formed FNL was thin and discontinuous,which would decrease the pore density and increase the coating's uniformness simultaneously.
文摘目的:对比Monaco计划系统Per Calculation(PC)和Per Control Point(PCP)两种统计噪声设置方式的剂量计算精度和计算效率。方法:选取30例IMRT/VMAT治疗计划,其中胸部和鼻咽部肿瘤各15例,两种噪声统计方式按照剂量计算精度递减的方式分别设置为5组和6组,评估其对计算时间和各剂量学评价指标的影响。结果:两种噪声统计方式计算时间(s)分别为131.78±26.91、6.76±3.57、1.75±0.57、0.84±0.24、0.84±0.24(PC)和259.20±80.15、73.53±26.00、9.18±3.26、3.60±1.67、1.59±0.75、1.13±0.49(PCP),均与计算精度呈负相关,且差异具有统计学意义(P<0.05);两组计划各剂量学评价指标箱图分析显示,均值和特定剂量的体积等指标四分位距较小,最大值和全局最大值等评价指标四分位距较大;两组计划各剂量学评价指标单因素ANOVA分析结果无统计学差异(P>0.05)。结论:两种统计噪声设置方式均可用于临床治疗计划计算精度设置;治疗计划全局最大值与统计噪声正相关,计算时间与统计噪声负相关;不同PC/PCP参数设置对均值和特定剂量的体积等评价影响较小,对全局和串行器官最大值影响较大。
