Aiming at the issue of sliding ratio,an internal gear pair is proposed which consists of an involute internal gear and a pinion with quadratic curve teeth.Particularly,the contact pattern is point contact and the pini...Aiming at the issue of sliding ratio,an internal gear pair is proposed which consists of an involute internal gear and a pinion with quadratic curve teeth.Particularly,the contact pattern is point contact and the pinion is generated based on an involute gear.The generation method and mathematical models of the gear pair are presented.The sliding ratio is calculated and the general calculation formulas of sliding ratios are developed.Also,the comparison between the involute gear and proposed gear is made.The adaptability of center distance and contact stress are also discussed.In addition,the gear pair was manufactured and inspected according to the exactitude solid model of the gear pair.In order to confirm this model to be effective,the efficiency experiment and the contrast experiment with the involute gear pair were performed.Furthermore,these two types of pinions were analyzed by scanning electron microscope and wear depths were measured by measuring center.The experiment results show that the efficiency of the internal gear pair is stable at a range about 97.1%to 98.6%and wear depth is less than 50%of the involute gear pair.The internal gear pair is expected to have excellent transmission performance.展开更多
Here, we make comments to the conclusions of the paper： LIU Shi-Da, Sill Shao-Ying, LIU Shi-Kuo, et al., ＂Vortex of Fluid Field as Viewed from Curvature＂ [Commun. Theor. Phys. 43 （2005） 604].
This dissertation aims at providing steady sensing for the shape detection of colonoscopes. The research especially deals with the key techniques of fiber bragg grating (FBG) large curvature sensor and sensor net, int...This dissertation aims at providing steady sensing for the shape detection of colonoscopes. The research especially deals with the key techniques of fiber bragg grating (FBG) large curvature sensor and sensor net, integrates the techniques of mechatronics and computer graphics, and develops real time FBG shape sensing system and incremental shape sensing system for colonoscopies.展开更多
In this paper we prove that tile set of Riemannian manifolds with parallel Ricci curvature, lower bounds for sectional curvature and injectivity radius and a upper bound for volume is coo compact in Gromov-Hausdroff t...In this paper we prove that tile set of Riemannian manifolds with parallel Ricci curvature, lower bounds for sectional curvature and injectivity radius and a upper bound for volume is coo compact in Gromov-Hausdroff topology. As an application we also prove a pinching result which states that a Ricci flat manifold is flat under certain conditions.展开更多
This paper focuses on the interaction between a micro/nano curved surface and a particle located inside the surface (hereafter abbreviated as in-surface-particle).Based on the exponential pair potential (namely 1/R2k)...This paper focuses on the interaction between a micro/nano curved surface and a particle located inside the surface (hereafter abbreviated as in-surface-particle).Based on the exponential pair potential (namely 1/R2k) between particles,the interaction potential between the micro/nano curved surface and the in-surface-particle is derived.The following results are shown:(a) For an even number of exponents in the pair potential,the interaction potential between the micro/nano curved surface and the in-surface-particle can be expressed as a unified function of the mean curvature and Gaussian curvature of the curved surface;(b) the curvatures and the gradients of curvatures of the micro/nano curved surface are the essential factors that dominate the driving force acting on the particle.展开更多
It is known that Gauss-Bonnet terms in higher dimensional gravity can produce an effective cosmological constant.We add extra examples to this picture by presenting explicitly two branches of accelerating vacuum solut...It is known that Gauss-Bonnet terms in higher dimensional gravity can produce an effective cosmological constant.We add extra examples to this picture by presenting explicitly two branches of accelerating vacuum solutions to the Einstein-Gauss-Bonnet gravities with a bare cosmological constant in 5 and 6 dimensions.Both branches of solutions are of constant curvature and the effective cosmological constants are independent of the acceleration parameter.One branch(the "-" branch) of the solutions is well defined in the limit when the Gauss-Bonnet parameter approaches zero,in which case the effective cosmological constant becomes identical with the bare value,while the other(i.e.the "+") branch is singular in the same limit,and beyond this singular limit,the effective cosmological constant is inversely proportional to the Gauss-Bonnet parameter with a negative constant of proportionality when the bare value vanishes.展开更多
基金Project(51575062)supported by the National Natural Science Foundation of ChinaProject(SM2014D202)supported by the Fund of Shanghai Key Laboratory of Spacecraft Mechanism,China
文摘Aiming at the issue of sliding ratio,an internal gear pair is proposed which consists of an involute internal gear and a pinion with quadratic curve teeth.Particularly,the contact pattern is point contact and the pinion is generated based on an involute gear.The generation method and mathematical models of the gear pair are presented.The sliding ratio is calculated and the general calculation formulas of sliding ratios are developed.Also,the comparison between the involute gear and proposed gear is made.The adaptability of center distance and contact stress are also discussed.In addition,the gear pair was manufactured and inspected according to the exactitude solid model of the gear pair.In order to confirm this model to be effective,the efficiency experiment and the contrast experiment with the involute gear pair were performed.Furthermore,these two types of pinions were analyzed by scanning electron microscope and wear depths were measured by measuring center.The experiment results show that the efficiency of the internal gear pair is stable at a range about 97.1%to 98.6%and wear depth is less than 50%of the involute gear pair.The internal gear pair is expected to have excellent transmission performance.
文摘Here, we make comments to the conclusions of the paper： LIU Shi-Da, Sill Shao-Ying, LIU Shi-Kuo, et al., ＂Vortex of Fluid Field as Viewed from Curvature＂ [Commun. Theor. Phys. 43 （2005） 604].
文摘This dissertation aims at providing steady sensing for the shape detection of colonoscopes. The research especially deals with the key techniques of fiber bragg grating (FBG) large curvature sensor and sensor net, integrates the techniques of mechatronics and computer graphics, and develops real time FBG shape sensing system and incremental shape sensing system for colonoscopies.
基金Supported by National Natural Science Foundation of China (19971081)
文摘In this paper we prove that tile set of Riemannian manifolds with parallel Ricci curvature, lower bounds for sectional curvature and injectivity radius and a upper bound for volume is coo compact in Gromov-Hausdroff topology. As an application we also prove a pinching result which states that a Ricci flat manifold is flat under certain conditions.
基金supported by the National Natural Sciences Foundation of China (Grant Nos.11072125 and 10872114)the Natural Science Foundation of Jiangsu province (Grant No. SBK201140044)
文摘This paper focuses on the interaction between a micro/nano curved surface and a particle located inside the surface (hereafter abbreviated as in-surface-particle).Based on the exponential pair potential (namely 1/R2k) between particles,the interaction potential between the micro/nano curved surface and the in-surface-particle is derived.The following results are shown:(a) For an even number of exponents in the pair potential,the interaction potential between the micro/nano curved surface and the in-surface-particle can be expressed as a unified function of the mean curvature and Gaussian curvature of the curved surface;(b) the curvatures and the gradients of curvatures of the micro/nano curved surface are the essential factors that dominate the driving force acting on the particle.
基金Supported by the National Natural Science Foundation of China under Grant No. 10875059the Special Fund for Theoretical Physics from the National Natural Science Foundation of China under Grant No. 10947203
文摘It is known that Gauss-Bonnet terms in higher dimensional gravity can produce an effective cosmological constant.We add extra examples to this picture by presenting explicitly two branches of accelerating vacuum solutions to the Einstein-Gauss-Bonnet gravities with a bare cosmological constant in 5 and 6 dimensions.Both branches of solutions are of constant curvature and the effective cosmological constants are independent of the acceleration parameter.One branch(the "-" branch) of the solutions is well defined in the limit when the Gauss-Bonnet parameter approaches zero,in which case the effective cosmological constant becomes identical with the bare value,while the other(i.e.the "+") branch is singular in the same limit,and beyond this singular limit,the effective cosmological constant is inversely proportional to the Gauss-Bonnet parameter with a negative constant of proportionality when the bare value vanishes.
