Based on Newton ' s second law,the bend-torsion-shaft coupling nonlinear dynamic model and equations of power split gear transmission system are established.According to the principle of tooth profile modification...Based on Newton ' s second law,the bend-torsion-shaft coupling nonlinear dynamic model and equations of power split gear transmission system are established.According to the principle of tooth profile modification,the tooth profile modification is considered as time-varying gear backlash function acting along the line of action.Then the dynamic functions are solved by using Runge-Kutta numerical method.After analyzing the effect of tooth profile modification quantity( TPMQ) and relative tooth profile modification length( TPML) to the nonlinear dynamic characteristics of power split gear transmission,the following conclusions are drawn:1 The TPMQ of a certain stage transmission affects the vibration of its own stage more significantly than the other stage,and the coupling effect between two stages can be ignored usually in the modification design;2 If the first stage TPMLs are less than 0.3,the influence of the first stage TPMLs to the first stage transmission vibration is much more greatly than the influence of the second stage TPMLs to the first stage transmission vibration,or else both the first and second stage TPMLs affect the first stage transmission vibration largely.The same is true for the second stage TPMLs,and the cutoff value is 0.2;3 The TPMQ affects the vibration of power split gear transmission system more principally than the TPML,and should be top-priority in the modification design.展开更多
目的:比较光固化纳米树脂与光固化复合树脂在前牙间隙修复中的红白美学效果及咀嚼功能差异,为临床材料选择提供依据。方法:选取2021年12月至2024年12月在医院接受前牙间隙修复治疗的86例前牙间隙≤3mm患者作为研究对象,随机分为光固化...目的:比较光固化纳米树脂与光固化复合树脂在前牙间隙修复中的红白美学效果及咀嚼功能差异,为临床材料选择提供依据。方法:选取2021年12月至2024年12月在医院接受前牙间隙修复治疗的86例前牙间隙≤3mm患者作为研究对象,随机分为光固化纳米树脂组(n=44)和光固化复合树脂组(n=42)。光固化纳米树脂组采用FiltekTM Supreme Ultra纳米树脂,光固化复合树脂组使用Herculite Ultra复合树脂。术后3 m,通过改良美国公共健康协会标准(United States Public Health Service,USPHS)标准评估红白美学效果(修复体形态、颜色匹配、边缘密合度、牙龈健康),采用T-ScanIII咬合力仪及标准化咀嚼效率测试评价功能恢复,并进一步统计分析牙敏感情况。结果:光固化纳米树脂组在修复体形态匹配、修复体颜色匹配、及牙龈健康方面均明显高于复合树脂组(P<0.05)。纳米树脂组咬合力提升幅度及咬合效率均明显高于复合树脂组(P<0.05)。在治疗后1 d和1 w时,纳米树脂组相较于复合树脂组牙敏感发生率降低(P<0.05),两组总有效率无明显差异(P>0.05)。结论:光固化纳米树脂通过纳米级填料的光学适配性和界面力学优化,在前牙间隙修复中实现了更优的红白美学效果与咀嚼功能恢复,降低牙敏感发生率,其优势源于填料粒径仿生性、低聚合收缩率及弹性模量与牙体组织的生物力学匹配性。展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.2009AA04Z404)
文摘Based on Newton ' s second law,the bend-torsion-shaft coupling nonlinear dynamic model and equations of power split gear transmission system are established.According to the principle of tooth profile modification,the tooth profile modification is considered as time-varying gear backlash function acting along the line of action.Then the dynamic functions are solved by using Runge-Kutta numerical method.After analyzing the effect of tooth profile modification quantity( TPMQ) and relative tooth profile modification length( TPML) to the nonlinear dynamic characteristics of power split gear transmission,the following conclusions are drawn:1 The TPMQ of a certain stage transmission affects the vibration of its own stage more significantly than the other stage,and the coupling effect between two stages can be ignored usually in the modification design;2 If the first stage TPMLs are less than 0.3,the influence of the first stage TPMLs to the first stage transmission vibration is much more greatly than the influence of the second stage TPMLs to the first stage transmission vibration,or else both the first and second stage TPMLs affect the first stage transmission vibration largely.The same is true for the second stage TPMLs,and the cutoff value is 0.2;3 The TPMQ affects the vibration of power split gear transmission system more principally than the TPML,and should be top-priority in the modification design.
文摘目的:比较光固化纳米树脂与光固化复合树脂在前牙间隙修复中的红白美学效果及咀嚼功能差异,为临床材料选择提供依据。方法:选取2021年12月至2024年12月在医院接受前牙间隙修复治疗的86例前牙间隙≤3mm患者作为研究对象,随机分为光固化纳米树脂组(n=44)和光固化复合树脂组(n=42)。光固化纳米树脂组采用FiltekTM Supreme Ultra纳米树脂,光固化复合树脂组使用Herculite Ultra复合树脂。术后3 m,通过改良美国公共健康协会标准(United States Public Health Service,USPHS)标准评估红白美学效果(修复体形态、颜色匹配、边缘密合度、牙龈健康),采用T-ScanIII咬合力仪及标准化咀嚼效率测试评价功能恢复,并进一步统计分析牙敏感情况。结果:光固化纳米树脂组在修复体形态匹配、修复体颜色匹配、及牙龈健康方面均明显高于复合树脂组(P<0.05)。纳米树脂组咬合力提升幅度及咬合效率均明显高于复合树脂组(P<0.05)。在治疗后1 d和1 w时,纳米树脂组相较于复合树脂组牙敏感发生率降低(P<0.05),两组总有效率无明显差异(P>0.05)。结论:光固化纳米树脂通过纳米级填料的光学适配性和界面力学优化,在前牙间隙修复中实现了更优的红白美学效果与咀嚼功能恢复,降低牙敏感发生率,其优势源于填料粒径仿生性、低聚合收缩率及弹性模量与牙体组织的生物力学匹配性。
