From the general formula for calculating the efficiency of planetary geartrains, the efficiency of the double crank ring-plate-type pin-cycloidal gear planetary drive isderived. To prove the theory, an experimental st...From the general formula for calculating the efficiency of planetary geartrains, the efficiency of the double crank ring-plate-type pin-cycloidal gear planetary drive isderived. To prove the theory, an experimental study has been conducted. The tested value of theefficiency of a sample set of the new-type drive in the experiment agrees with the calculated one.It shows that the new-type drive is of not merely high bearing capacity, but also quite highefficiency.展开更多
A dynamic quasi-continuum model is presented to analyze free vibration of plate-type cubic crystal nano-materials.According to the Hamilton principle,fundamental governing equations in terms of displacement components...A dynamic quasi-continuum model is presented to analyze free vibration of plate-type cubic crystal nano-materials.According to the Hamilton principle,fundamental governing equations in terms of displacement components and angles of rotations are given.As an application of the model,the cylindrical bending deformation of the structure fixed at two ends is analyzed,and a theoretical formula evaluating the fundamental frequency is obtained by using Galerkin's method.Meanwhile,the solution for the classical continuous plate model is also derived,and the size-dependent elastic modulus and Poisson's ratio are taken in computation.The frequencies corresponding to different atomic layers are numerically presented for the plate-type NaC l nano-materials.Furthermore,a molecular dynamics(MD)simulation is conducted with the code LAMMPS.The comparison shows that the present quasi-continuum model is valid,and it may be used as an alternative model,which reflects scale effects in analyzing dynamic behaviors of such plate-type nano-materials.展开更多
目的:探讨中医接骨学(Chinese osteosynthesis,CO)理论指导下接骨支架与切开复位钢板内固定在治疗不稳定型(AO-23C型)桡骨远端骨折的近期临床疗效。方法:回顾性分析2022年1月至2023年2月48例不稳定型桡骨远端骨折患者,分为CO接骨架组和...目的:探讨中医接骨学(Chinese osteosynthesis,CO)理论指导下接骨支架与切开复位钢板内固定在治疗不稳定型(AO-23C型)桡骨远端骨折的近期临床疗效。方法:回顾性分析2022年1月至2023年2月48例不稳定型桡骨远端骨折患者,分为CO接骨架组和内固定组。CO接骨架组25例,男7例,女18例;年龄37~56(52.6±11.3)岁;车祸伤7例,跌伤18例;闭合性骨折25例,开放性骨折0例;采用闭合复位CO接骨支架治疗。内固定组23例,男8例,女15例;年龄41~59(53.3±13.7)岁;车祸伤8例,摔伤15例;闭合性骨折23例;采用切开复位钢板内固定方法。评价两组的围手术期资料(受伤至手术时间、手术时长、失血量、住院时间)、术后1年上肢功能障碍评分量表(disabilities of the arm,shoulder and hand,DASH)缩略版(QuickDASH)评分、疼痛视觉模拟评分(visual analogue scale,VAS)、活动范围及握力评估、影像学表现(掌倾角、尺偏角、桡骨长度、关节面台阶、关节内间隙)和并发症等情况。结果:两组术后均获随访,时间0~24(16.0±3.8)个月。CO接骨架组和内固定组比较,CO接骨架组受伤至手术时间[(2.4±3.3)dvs(7.4±3.7)d]短,手术时间[(56.27±15.23)min vs(74.10±5.26)min]短、失血量[(14.52±6.54)ml vs(32.32±10.03)ml]少、住院时间[(14.04±3.24)d vs(16.45±3.05)d]少(P<0.05)。术后12个月两组QuickDASH评分比较[(9.21±1.64)分vs(7.04±3.64)分],差异无统计学意义(P>0.05)。术后6周及1、3个月两组VAS比较,差异均无统计学意义(P>0.05)。末次随访两组活动范围及握力比较,差异均无统计学意义(P>0.05)。术后12个月与内固定组影像学比较,CO接骨架组掌倾角[(17.90±2.18)°vs(19.87±3.21)°]更小、关节面台阶[(0.11±0.03)mm vs(0.17±0.02)mm]更少、桡骨长度[(8.16±1.11)mm vs(9.59±1.02)mm]更短(P<0.05);两组尺偏角度数、关节内间隙比较,差异均无统计学意义(P>0.05)。其中CO接骨架组(25例中的23例)和内固定组(23例中的21例)存在允许范围内的缩小,差异无统计学意义(P=0.29);两组并发症比较,差异无统计学意义(P>0.05)。结论:CO接骨架和切开复位钢板内固定均是治疗不稳定型桡骨远端骨折的有效疗法,且接骨支架术从受伤至手术的等待时间更短、术中出血更少、耗时更短;钢板内固定术控制桡骨短缩更优。展开更多
目的:Meta分析钢板与外固定架固定治疗AO-C型桡骨远端骨折的临床疗效。方法:检索PubMed、Embase、Cochrane Library、Web of Science、中国知网、万方、维普和SinoMed数据库所有关于AO-C型桡骨远端骨折的随机对照临床试验的文献,检索时...目的:Meta分析钢板与外固定架固定治疗AO-C型桡骨远端骨折的临床疗效。方法:检索PubMed、Embase、Cochrane Library、Web of Science、中国知网、万方、维普和SinoMed数据库所有关于AO-C型桡骨远端骨折的随机对照临床试验的文献,检索时限均从各数据库建库到2023年6月30日。纳入研究参照Cochrane手册(Version6.3,2022)进行信息提取、文献质量评价,采用RevMan 5.4软件进行发表偏倚风险评价、检验异质性并进行Meta分析。结局指标为:影像学解剖指标(掌倾角、尺偏角、桡骨高度)、腕关节活动度(屈伸、旋转、尺桡偏)、并发症发生率、手术治疗情况比较(手术出血量、手术时间、住院时间、骨折愈合时间)和腕关节功能评分及相关量表。结果:(1)共纳入28项研究,患者共计2192例,包括1096例钢板内固定组和1096例外固定架组。(2)Meta分析结果显示:外固定架组的手术出血量[MD=-37.93,95%CI(-48.54,-27.31),P<0.00001]、手术时间[MD=-31.58,95%CI(-48.96,-14.20),P=0.0004]、住院时间[MD=-4.58,95%CI(-5.44,-3.71),P<0.00001]、骨折愈合时间[MD=-0.88,95%CI(-1.35,-0.41),P=0.0002]均显著优于钢板内固定组(P<0.05)。(3)两组的掌倾角[MD=-0.17,95%CI(-0.95,0.61),P=0.68]、尺偏角[MD=0.22,95%CI(-0.73,1.17),P=0.65]、桡骨高度[MD=-0.24,95%CI(-1.15,0.67),P=0.60],屈伸[MD=-5.63,95%CI(-11.85,0.58),P=0.08]、旋转[MD=-5.80,95%CI(-12.77,1.17),P=0.10]、尺桡偏[MD=-2.86,95%CI(-10.87,5.15),P=0.48],并发症发生率[RR=0.96,95%CI(0.63,1.46),P=0.83],Gartland-Werley腕部临床评分[MD=0.13,95%CI(-0.80,1.06),P=0.78]、Gartland-Werley腕部临床评分优良率[RR=0.93,95%CI(0.87,1.01),P=0.08]、Cooney腕关节评分优良率[RR=0.99,95%CI(0.62,1.59),P=0.98]、腕关节DASH评分[MD=-4.67,95%CI(-14.96,5.62),P=0.37]的差异均无统计学意义(P>0.05)。结论:与钢板内固定相比,外固定架治疗AO-C型桡骨远端骨折可以显著减少手术出血量、缩短手术时间与住院时间和骨折愈合时间,其影像学解剖指标、腕关节活动度、并发症发生率和腕关节功能评分两者相当。展开更多
基金This project is supported by National Natural Science Foundation of China (No.50175011).
文摘From the general formula for calculating the efficiency of planetary geartrains, the efficiency of the double crank ring-plate-type pin-cycloidal gear planetary drive isderived. To prove the theory, an experimental study has been conducted. The tested value of theefficiency of a sample set of the new-type drive in the experiment agrees with the calculated one.It shows that the new-type drive is of not merely high bearing capacity, but also quite highefficiency.
文摘A dynamic quasi-continuum model is presented to analyze free vibration of plate-type cubic crystal nano-materials.According to the Hamilton principle,fundamental governing equations in terms of displacement components and angles of rotations are given.As an application of the model,the cylindrical bending deformation of the structure fixed at two ends is analyzed,and a theoretical formula evaluating the fundamental frequency is obtained by using Galerkin's method.Meanwhile,the solution for the classical continuous plate model is also derived,and the size-dependent elastic modulus and Poisson's ratio are taken in computation.The frequencies corresponding to different atomic layers are numerically presented for the plate-type NaC l nano-materials.Furthermore,a molecular dynamics(MD)simulation is conducted with the code LAMMPS.The comparison shows that the present quasi-continuum model is valid,and it may be used as an alternative model,which reflects scale effects in analyzing dynamic behaviors of such plate-type nano-materials.
文摘目的:探讨中医接骨学(Chinese osteosynthesis,CO)理论指导下接骨支架与切开复位钢板内固定在治疗不稳定型(AO-23C型)桡骨远端骨折的近期临床疗效。方法:回顾性分析2022年1月至2023年2月48例不稳定型桡骨远端骨折患者,分为CO接骨架组和内固定组。CO接骨架组25例,男7例,女18例;年龄37~56(52.6±11.3)岁;车祸伤7例,跌伤18例;闭合性骨折25例,开放性骨折0例;采用闭合复位CO接骨支架治疗。内固定组23例,男8例,女15例;年龄41~59(53.3±13.7)岁;车祸伤8例,摔伤15例;闭合性骨折23例;采用切开复位钢板内固定方法。评价两组的围手术期资料(受伤至手术时间、手术时长、失血量、住院时间)、术后1年上肢功能障碍评分量表(disabilities of the arm,shoulder and hand,DASH)缩略版(QuickDASH)评分、疼痛视觉模拟评分(visual analogue scale,VAS)、活动范围及握力评估、影像学表现(掌倾角、尺偏角、桡骨长度、关节面台阶、关节内间隙)和并发症等情况。结果:两组术后均获随访,时间0~24(16.0±3.8)个月。CO接骨架组和内固定组比较,CO接骨架组受伤至手术时间[(2.4±3.3)dvs(7.4±3.7)d]短,手术时间[(56.27±15.23)min vs(74.10±5.26)min]短、失血量[(14.52±6.54)ml vs(32.32±10.03)ml]少、住院时间[(14.04±3.24)d vs(16.45±3.05)d]少(P<0.05)。术后12个月两组QuickDASH评分比较[(9.21±1.64)分vs(7.04±3.64)分],差异无统计学意义(P>0.05)。术后6周及1、3个月两组VAS比较,差异均无统计学意义(P>0.05)。末次随访两组活动范围及握力比较,差异均无统计学意义(P>0.05)。术后12个月与内固定组影像学比较,CO接骨架组掌倾角[(17.90±2.18)°vs(19.87±3.21)°]更小、关节面台阶[(0.11±0.03)mm vs(0.17±0.02)mm]更少、桡骨长度[(8.16±1.11)mm vs(9.59±1.02)mm]更短(P<0.05);两组尺偏角度数、关节内间隙比较,差异均无统计学意义(P>0.05)。其中CO接骨架组(25例中的23例)和内固定组(23例中的21例)存在允许范围内的缩小,差异无统计学意义(P=0.29);两组并发症比较,差异无统计学意义(P>0.05)。结论:CO接骨架和切开复位钢板内固定均是治疗不稳定型桡骨远端骨折的有效疗法,且接骨支架术从受伤至手术的等待时间更短、术中出血更少、耗时更短;钢板内固定术控制桡骨短缩更优。
文摘目的:Meta分析钢板与外固定架固定治疗AO-C型桡骨远端骨折的临床疗效。方法:检索PubMed、Embase、Cochrane Library、Web of Science、中国知网、万方、维普和SinoMed数据库所有关于AO-C型桡骨远端骨折的随机对照临床试验的文献,检索时限均从各数据库建库到2023年6月30日。纳入研究参照Cochrane手册(Version6.3,2022)进行信息提取、文献质量评价,采用RevMan 5.4软件进行发表偏倚风险评价、检验异质性并进行Meta分析。结局指标为:影像学解剖指标(掌倾角、尺偏角、桡骨高度)、腕关节活动度(屈伸、旋转、尺桡偏)、并发症发生率、手术治疗情况比较(手术出血量、手术时间、住院时间、骨折愈合时间)和腕关节功能评分及相关量表。结果:(1)共纳入28项研究,患者共计2192例,包括1096例钢板内固定组和1096例外固定架组。(2)Meta分析结果显示:外固定架组的手术出血量[MD=-37.93,95%CI(-48.54,-27.31),P<0.00001]、手术时间[MD=-31.58,95%CI(-48.96,-14.20),P=0.0004]、住院时间[MD=-4.58,95%CI(-5.44,-3.71),P<0.00001]、骨折愈合时间[MD=-0.88,95%CI(-1.35,-0.41),P=0.0002]均显著优于钢板内固定组(P<0.05)。(3)两组的掌倾角[MD=-0.17,95%CI(-0.95,0.61),P=0.68]、尺偏角[MD=0.22,95%CI(-0.73,1.17),P=0.65]、桡骨高度[MD=-0.24,95%CI(-1.15,0.67),P=0.60],屈伸[MD=-5.63,95%CI(-11.85,0.58),P=0.08]、旋转[MD=-5.80,95%CI(-12.77,1.17),P=0.10]、尺桡偏[MD=-2.86,95%CI(-10.87,5.15),P=0.48],并发症发生率[RR=0.96,95%CI(0.63,1.46),P=0.83],Gartland-Werley腕部临床评分[MD=0.13,95%CI(-0.80,1.06),P=0.78]、Gartland-Werley腕部临床评分优良率[RR=0.93,95%CI(0.87,1.01),P=0.08]、Cooney腕关节评分优良率[RR=0.99,95%CI(0.62,1.59),P=0.98]、腕关节DASH评分[MD=-4.67,95%CI(-14.96,5.62),P=0.37]的差异均无统计学意义(P>0.05)。结论:与钢板内固定相比,外固定架治疗AO-C型桡骨远端骨折可以显著减少手术出血量、缩短手术时间与住院时间和骨折愈合时间,其影像学解剖指标、腕关节活动度、并发症发生率和腕关节功能评分两者相当。
