目的:采用定量CT评判仙灵骨葆胶囊治疗骨质疏松的临床效果。方法:使用双能X线及Qct筛查出60例骨质疏松患者,随机分为两组。以钙尔奇D、阿法骨化醇软胶囊为基础治疗,观察组联合仙灵骨葆胶囊口服,对照组联合鲑鱼降钙素注射治疗,两组患者...目的:采用定量CT评判仙灵骨葆胶囊治疗骨质疏松的临床效果。方法:使用双能X线及Qct筛查出60例骨质疏松患者,随机分为两组。以钙尔奇D、阿法骨化醇软胶囊为基础治疗,观察组联合仙灵骨葆胶囊口服,对照组联合鲑鱼降钙素注射治疗,两组患者连续治疗6个月。评估指标为腰椎骨密度(bone mineral density,BMD)值,患者VAS疼痛评分。结果:采用定量CT测量两组患者腰椎骨密度结果显示,与治疗前相比,观察组和对照组治疗后腰椎骨密度都有明显提高(t=-8.953,P<0.01;t=-5.046,P<0.01),且观察组高于对照组(t=5.651,P<0.01);观察组和对照组的VAS疼痛评分均较治疗前显著降低(t=10.79,P<0.01;t=8.68,P<0.01),但治疗后观察组腰背疼痛VAS评分明显高于对照组(t=0.655,P<0.01)。结论:仙灵骨葆胶囊提高骨质疏松症患者骨密度的作用优于鲑鱼降钙素,但对缓解骨质疏松患者腰背痛较鲑鱼降钙素差。展开更多
This paper proposes a new approach to mial function of transmission error （TE） for spiral design and implement a seventh-order polyno- bevel gears with an aim to reduce the running vibration and noise of gear drive ...This paper proposes a new approach to mial function of transmission error （TE） for spiral design and implement a seventh-order polyno- bevel gears with an aim to reduce the running vibration and noise of gear drive and improve the loaded distribution of the tooth. Based on the constraint conditions of predesigned seventh-order polynomial function curve and the theory of linear algebra, the polynomial coefficients of the seventh-order polynomial function of transmission error can be obtained. By applying a method named reverse tooth contact analysis, the modified roll coefficients as well as parts of machine-tool settings for the face-milling of spiral bevel gears can be individually determined. Therefore, a predesigned seventh-order polynomial function of transmission error for spiral bevel gears can be obtained by the modified roll with high-order coef- ficients, and comparisons of the seventh-order polynomial and parabolic functions of transmission error are also performed. The achievement of spiral bevel gears with the seventh-order function of transmission error can be accomplished on a universal Cartesian-type hypoid gear generator or a numerically controlled cradle-style hypoid gear generator due to its simple generating motion of axes of the cradle and the work piece. The results of a numerical example show that the bending stresses of the tooth of seventh-order are less than those of a parabolic one, while the contact stresses remain almost eouivalent.展开更多
A fabrication method is adopted for which an imaginary gear simultaneously realizes conjugated meshing with an arc tooth cylindrical gear and an arc tooth face-gear. The cutter fillet and tooth crest edge form the too...A fabrication method is adopted for which an imaginary gear simultaneously realizes conjugated meshing with an arc tooth cylindrical gear and an arc tooth face-gear. The cutter fillet and tooth crest edge form the tooth root fillet of the gear, and the linear tooth surface equation of the imaginary gear and the position vector of the curvature center of the cutter fillet arc constructed with certain cutter inclination to deduce a working arc tooth surface equation. The tooth root fillet equation of the arc tooth face-gear is derived from the meshing geometry and kinematics. A numer- ically controlled machining model of the arc tooth face-gear is established through the transforma- tion of adjustment parameters from the cutter-tilt milling machine to a common multi-axis NC machine. Motion parameters of each movement axis of the NC machine are acquired. A processing example is presented to verify the precision of the fabrication method in processing the arc tooth face-gear. The method provides a theoretical and tentative basis for the analysis of tooth surface contact stress, tooth root bending stress and dynamics. A hobbing test is conducted to demonstrate the good meshing condition of the arc tooth face-gear pair.展开更多
文摘目的:采用定量CT评判仙灵骨葆胶囊治疗骨质疏松的临床效果。方法:使用双能X线及Qct筛查出60例骨质疏松患者,随机分为两组。以钙尔奇D、阿法骨化醇软胶囊为基础治疗,观察组联合仙灵骨葆胶囊口服,对照组联合鲑鱼降钙素注射治疗,两组患者连续治疗6个月。评估指标为腰椎骨密度(bone mineral density,BMD)值,患者VAS疼痛评分。结果:采用定量CT测量两组患者腰椎骨密度结果显示,与治疗前相比,观察组和对照组治疗后腰椎骨密度都有明显提高(t=-8.953,P<0.01;t=-5.046,P<0.01),且观察组高于对照组(t=5.651,P<0.01);观察组和对照组的VAS疼痛评分均较治疗前显著降低(t=10.79,P<0.01;t=8.68,P<0.01),但治疗后观察组腰背疼痛VAS评分明显高于对照组(t=0.655,P<0.01)。结论:仙灵骨葆胶囊提高骨质疏松症患者骨密度的作用优于鲑鱼降钙素,但对缓解骨质疏松患者腰背痛较鲑鱼降钙素差。
基金the National Science Foundation of China (Nos.51205310 and 51175423)the Fundamental Research Funds for the Central Universities (Nos.2013G3252005 and 2013G2252027)
文摘This paper proposes a new approach to mial function of transmission error （TE） for spiral design and implement a seventh-order polyno- bevel gears with an aim to reduce the running vibration and noise of gear drive and improve the loaded distribution of the tooth. Based on the constraint conditions of predesigned seventh-order polynomial function curve and the theory of linear algebra, the polynomial coefficients of the seventh-order polynomial function of transmission error can be obtained. By applying a method named reverse tooth contact analysis, the modified roll coefficients as well as parts of machine-tool settings for the face-milling of spiral bevel gears can be individually determined. Therefore, a predesigned seventh-order polynomial function of transmission error for spiral bevel gears can be obtained by the modified roll with high-order coef- ficients, and comparisons of the seventh-order polynomial and parabolic functions of transmission error are also performed. The achievement of spiral bevel gears with the seventh-order function of transmission error can be accomplished on a universal Cartesian-type hypoid gear generator or a numerically controlled cradle-style hypoid gear generator due to its simple generating motion of axes of the cradle and the work piece. The results of a numerical example show that the bending stresses of the tooth of seventh-order are less than those of a parabolic one, while the contact stresses remain almost eouivalent.
基金co-supported by the National Natural Science Foundation of China (No.51175423)the Aeronautical Science Foundation of China (No.2011ZB55002)+1 种基金Science & Technology Innovation Talents in Universities of Henan Province,‘‘HASTIT’’(No.2012HASTIT023)Assistance Scheme of Young Backbone Teachers of Henan Province Colleges and Universities (No.2010GGJS-147)
文摘A fabrication method is adopted for which an imaginary gear simultaneously realizes conjugated meshing with an arc tooth cylindrical gear and an arc tooth face-gear. The cutter fillet and tooth crest edge form the tooth root fillet of the gear, and the linear tooth surface equation of the imaginary gear and the position vector of the curvature center of the cutter fillet arc constructed with certain cutter inclination to deduce a working arc tooth surface equation. The tooth root fillet equation of the arc tooth face-gear is derived from the meshing geometry and kinematics. A numer- ically controlled machining model of the arc tooth face-gear is established through the transforma- tion of adjustment parameters from the cutter-tilt milling machine to a common multi-axis NC machine. Motion parameters of each movement axis of the NC machine are acquired. A processing example is presented to verify the precision of the fabrication method in processing the arc tooth face-gear. The method provides a theoretical and tentative basis for the analysis of tooth surface contact stress, tooth root bending stress and dynamics. A hobbing test is conducted to demonstrate the good meshing condition of the arc tooth face-gear pair.
