Straight bevel gears are widely applied in automotive, aerospace, chemical and many other fields as one of the most common type of gears. Currently, the researches on straight bevel gears have focused on the fields of...Straight bevel gears are widely applied in automotive, aerospace, chemical and many other fields as one of the most common type of gears. Currently, the researches on straight bevel gears have focused on the fields of fatigue, wear, noise and vibration, while little attention is paid to the effect of multiple alignment errors on the gear tooth wear. To study the influence of alignment errors on the gear tooth wear, a simulated model of a straight bevel gear pair is established. Then, the contact pressure on the tooth surface is analyzed under the various alignment errors according to the Archard wear relationship. The main combinations of alignment errors played vital roles on the tooth wear are investigated. The result shows that under the single alignment error, the contact pressure moves to the tooth heel and increases greatly at here when ？P=0.1 or ？G=0.1; when ？E=–0.03, the contact pressure greatly increases at the tooth heel, but it obviously increases at the tooth toe when ？E=0.03; the alignment error ？γ=1 has little effect on the contact pressure on the tooth surface. Moreover, the combination of ？P, ？G, ？E〈0 and ？γ is the most dangerous type among the multiple alignment errors. This research provides valuable guidelines for predicting the tooth wear under various alignment errors.展开更多
The influences of subsurface cracks,distributing along the axial direction,on the rolling contact fatigue(RCF)faliure in a bearing ring are investigated.A realistic three-dimensional model of the bearing ring containi...The influences of subsurface cracks,distributing along the axial direction,on the rolling contact fatigue(RCF)faliure in a bearing ring are investigated.A realistic three-dimensional model of the bearing ring containing three subsurface cracks is used to evaluate the fatigue crack propagation based on stress intensity factor(SIF)calculations.Moreover,the distributions of the subsurface cracks along the axial direction are varied to study their effects on RCF.The results provide valuable guidelines for enhanced understanding of RCF in bearings.展开更多
OBJECTIVE: To evaluate the effect of ZiYin Xiehuo granules(ZYXH) and Zishen Qinggan granules(ZSQG) on partial precocious puberty(PPP).METHODS: This was a multicenter, randomized, single-blind, positive-controlled tria...OBJECTIVE: To evaluate the effect of ZiYin Xiehuo granules(ZYXH) and Zishen Qinggan granules(ZSQG) on partial precocious puberty(PPP).METHODS: This was a multicenter, randomized, single-blind, positive-controlled trial. A total of 143 pa-tients were assigned to either the ZYXH group or the ZSQG group using a random number table. The ZYXH group received ZYXH three times daily for 6 months and the ZSQG group received ZSQG three times daily for 6 months. Mammary nucleus diameter; the results of uterus, ovarian, and maximum follicle measures; and Chinese medicine symptom pattern scores were compared at baseline and after 3 months and 6 months of treatment.RESULTS: After 3 months' treatment, there were no significant differences between the two groups in mammary nucleus index changes(left 3.4 ± 3.1 vs3.5 ± 3.1, P = 0.790; right 3.0 ± 2.9 vs 3.6 ± 3.0, P =0.719). The uterine volume in the ZYXH group was smaller than that in the ZSQG group(2.1 ± 1.6 vs2.6 ± 2.2, P = 0.006). There were no significant between-group differences in ovarian volume and maximum follicular diameter on either side(ovarian volume: left 1.2 ± 0.7 vs 1.3 ± 0.6, P = 0.8; right1.2 ± 0.7 vs 1.4 ± 1.1, P = 0.984; maximum follicular diameter: left 3.9 ± 1.7 vs 3.5 ± 2.2, P = 0.158; right3.5 ± 1.7 vs 3.9 ± 2.1, P = 0.314).CONCLUSION: ZYXH granules and ZSQG granules both affected the size of the mammary nucleus in girls with PPP, and improved Chinese medicine symptom patterns. ZYXH granules showed slight advantages over ZSQG granules in terms of the decrease in the size of the uterus, ovaries, and ovarian follicles.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.51105287)Innovative Research Team Development Program of Ministry of Education of China(Grant No.IRT13087)
文摘Straight bevel gears are widely applied in automotive, aerospace, chemical and many other fields as one of the most common type of gears. Currently, the researches on straight bevel gears have focused on the fields of fatigue, wear, noise and vibration, while little attention is paid to the effect of multiple alignment errors on the gear tooth wear. To study the influence of alignment errors on the gear tooth wear, a simulated model of a straight bevel gear pair is established. Then, the contact pressure on the tooth surface is analyzed under the various alignment errors according to the Archard wear relationship. The main combinations of alignment errors played vital roles on the tooth wear are investigated. The result shows that under the single alignment error, the contact pressure moves to the tooth heel and increases greatly at here when ？P=0.1 or ？G=0.1; when ？E=–0.03, the contact pressure greatly increases at the tooth heel, but it obviously increases at the tooth toe when ？E=0.03; the alignment error ？γ=1 has little effect on the contact pressure on the tooth surface. Moreover, the combination of ？P, ？G, ？E〈0 and ？γ is the most dangerous type among the multiple alignment errors. This research provides valuable guidelines for predicting the tooth wear under various alignment errors.
基金supported by the National Basic Research Program of China(Grant No.2011CB706605)State Key Program of National Natural Science Foundation of China(Grant No.51135007)+1 种基金Innovative Research Groups of the National Natural Science Foundation of Hubei Province(Grant No.2011CDA12)the Fundamental Research Funds for the Central Universities(Grant Nos.2012-Ia-017,2013-IV-014)for the support given to this research
文摘The influences of subsurface cracks,distributing along the axial direction,on the rolling contact fatigue(RCF)faliure in a bearing ring are investigated.A realistic three-dimensional model of the bearing ring containing three subsurface cracks is used to evaluate the fatigue crack propagation based on stress intensity factor(SIF)calculations.Moreover,the distributions of the subsurface cracks along the axial direction are varied to study their effects on RCF.The results provide valuable guidelines for enhanced understanding of RCF in bearings.
基金Supported by the Shanghai Integrated Chinese and Western Medicine Key Diseases Construction Projects(No.zxbz2012-14)a Medical Guidance Item of the Shanghai Science and Technology Commission(No.12401906900)+1 种基金by the Chinese Medicine Prescription Project of the Shanghai Shenkang Hospital Development Center(No.SHDC12012414)by the Development Project of the Shanghai Peak
文摘OBJECTIVE: To evaluate the effect of ZiYin Xiehuo granules(ZYXH) and Zishen Qinggan granules(ZSQG) on partial precocious puberty(PPP).METHODS: This was a multicenter, randomized, single-blind, positive-controlled trial. A total of 143 pa-tients were assigned to either the ZYXH group or the ZSQG group using a random number table. The ZYXH group received ZYXH three times daily for 6 months and the ZSQG group received ZSQG three times daily for 6 months. Mammary nucleus diameter; the results of uterus, ovarian, and maximum follicle measures; and Chinese medicine symptom pattern scores were compared at baseline and after 3 months and 6 months of treatment.RESULTS: After 3 months' treatment, there were no significant differences between the two groups in mammary nucleus index changes(left 3.4 ± 3.1 vs3.5 ± 3.1, P = 0.790; right 3.0 ± 2.9 vs 3.6 ± 3.0, P =0.719). The uterine volume in the ZYXH group was smaller than that in the ZSQG group(2.1 ± 1.6 vs2.6 ± 2.2, P = 0.006). There were no significant between-group differences in ovarian volume and maximum follicular diameter on either side(ovarian volume: left 1.2 ± 0.7 vs 1.3 ± 0.6, P = 0.8; right1.2 ± 0.7 vs 1.4 ± 1.1, P = 0.984; maximum follicular diameter: left 3.9 ± 1.7 vs 3.5 ± 2.2, P = 0.158; right3.5 ± 1.7 vs 3.9 ± 2.1, P = 0.314).CONCLUSION: ZYXH granules and ZSQG granules both affected the size of the mammary nucleus in girls with PPP, and improved Chinese medicine symptom patterns. ZYXH granules showed slight advantages over ZSQG granules in terms of the decrease in the size of the uterus, ovaries, and ovarian follicles.
