This paper focuses on the analysis of running conditions and machining processes of conical cam with oscillating follower. We point out the common errors existing in the design and machining of the widely used plane e...This paper focuses on the analysis of running conditions and machining processes of conical cam with oscillating follower. We point out the common errors existing in the design and machining of the widely used plane expansion method of conical cam trough-out line. We show that the motion can be divided into two parts, i.e. the oscillating motion of oscillating bar and the rotary motion of oscillating bar relative to the conical cam. By increasing the rotary motion of oscillating bar, the motion path of tapered roller on oscillating bar (i.e. contour surface of conical cam) can be expanded on the cylinder. Based on these analyses, we present a creative and effective designing and machining method for 3D curve expansion of conical cam with oscillating follower.展开更多
A novel S-bend with tapered curved waveguides is proposed. The normalized transmitted power is greater than the conventional bend with weakly guided waveguides. Small size and low loss can be reached by the proposed S...A novel S-bend with tapered curved waveguides is proposed. The normalized transmitted power is greater than the conventional bend with weakly guided waveguides. Small size and low loss can be reached by the proposed S-bend.展开更多
The study adopts the variational method for analyzing the cantilever tapered beams under a tip load as well as a definite end displacement,and further determining the optimized shapes and materials that can minimize t...The study adopts the variational method for analyzing the cantilever tapered beams under a tip load as well as a definite end displacement,and further determining the optimized shapes and materials that can minimize the weights.Two types of beams are taken into account,i.e.,the Euler-Bernoulli beam without considering shear deformation and the Timoshenko beam with shear deformation.By using the energy theorem and the reference of isoperimetric problem,the width variation curves and the corresponding minimum masses are derived for both beam types.The optimized curve of beam width for the Euler-Bernoulli beam is found to be a linear function,but nonlinear for the Timoshenko beam.It is also found that the optimized curve in the Timoshenko beam case starts from non-zero at the tip end,but its tendency gradually approaches the one of the Euler-Bernoulli beam.The results indicate that with the increase of the Poisson’s ratio,the required minimum mass of the beam will increase no matter how the material changes,suggesting that the optimized mass for the case of Euler-Bernoulli beam is the lower boundary limit which the Timoshenko case cannot go beyond.Furthermore,the ratio r/E(density against Elastic Modulus)of the material should be as small as possible,while the ratio h2/L4 of the beam should be as large as possible in order to minimize the mass for the case of Euler-Bernoulli beam,of which the conclusion is extended to be applicable for the case of Timoshenko beam.In addition,the optimized curves for Euler-Bernoulli beam types are all found to be power functions of length for both tip point load cases and uniform load cases.展开更多
择伐作业已成为近自然林改造中的基本经营方式，如何在兼顾林业企业经济效益的前提下进行择伐成为森林可持续经营研究中的重要课题；森林经营单位硬件条件、经营水平的不断提高以及林内立木数据的大量传回，要求有一种新的经营理念和方...择伐作业已成为近自然林改造中的基本经营方式，如何在兼顾林业企业经济效益的前提下进行择伐成为森林可持续经营研究中的重要课题；森林经营单位硬件条件、经营水平的不断提高以及林内立木数据的大量传回，要求有一种新的经营理念和方法与之适应。提出泛储木场理念下的营销思想，探讨在该理念下的用材林经营方式。根据广西大青山林区内分布于上、中、下3个坡位，胸径12～48 cm 的米老排林立木数据，用统计模型的方法拟合此经营方式下米老排的树高曲线和削度方程，给出一种实现林木生长量最大化且没有储木场损失的米老排用材林营销流程。展开更多
基金Project supported by the National Natural Science Foundation of China (No. 50575205)the HiTech Research and Development Program (863) of China (No. 2006AA04Z233)and the Natural Science Foundation of Zhejiang Province (Nos. Y104243 and Y105686), China
文摘This paper focuses on the analysis of running conditions and machining processes of conical cam with oscillating follower. We point out the common errors existing in the design and machining of the widely used plane expansion method of conical cam trough-out line. We show that the motion can be divided into two parts, i.e. the oscillating motion of oscillating bar and the rotary motion of oscillating bar relative to the conical cam. By increasing the rotary motion of oscillating bar, the motion path of tapered roller on oscillating bar (i.e. contour surface of conical cam) can be expanded on the cylinder. Based on these analyses, we present a creative and effective designing and machining method for 3D curve expansion of conical cam with oscillating follower.
文摘A novel S-bend with tapered curved waveguides is proposed. The normalized transmitted power is greater than the conventional bend with weakly guided waveguides. Small size and low loss can be reached by the proposed S-bend.
基金supports from Xi’an Jiaotong–Liverpool University(RDF 14-02-44,RDF 15-01-38,RDF 18-01-23 and PGRS1906002)the Key Program Special Fund at XJTLU(Grant No.KSF-E-19)are gratefully acknowledged.
文摘The study adopts the variational method for analyzing the cantilever tapered beams under a tip load as well as a definite end displacement,and further determining the optimized shapes and materials that can minimize the weights.Two types of beams are taken into account,i.e.,the Euler-Bernoulli beam without considering shear deformation and the Timoshenko beam with shear deformation.By using the energy theorem and the reference of isoperimetric problem,the width variation curves and the corresponding minimum masses are derived for both beam types.The optimized curve of beam width for the Euler-Bernoulli beam is found to be a linear function,but nonlinear for the Timoshenko beam.It is also found that the optimized curve in the Timoshenko beam case starts from non-zero at the tip end,but its tendency gradually approaches the one of the Euler-Bernoulli beam.The results indicate that with the increase of the Poisson’s ratio,the required minimum mass of the beam will increase no matter how the material changes,suggesting that the optimized mass for the case of Euler-Bernoulli beam is the lower boundary limit which the Timoshenko case cannot go beyond.Furthermore,the ratio r/E(density against Elastic Modulus)of the material should be as small as possible,while the ratio h2/L4 of the beam should be as large as possible in order to minimize the mass for the case of Euler-Bernoulli beam,of which the conclusion is extended to be applicable for the case of Timoshenko beam.In addition,the optimized curves for Euler-Bernoulli beam types are all found to be power functions of length for both tip point load cases and uniform load cases.
文摘择伐作业已成为近自然林改造中的基本经营方式，如何在兼顾林业企业经济效益的前提下进行择伐成为森林可持续经营研究中的重要课题；森林经营单位硬件条件、经营水平的不断提高以及林内立木数据的大量传回，要求有一种新的经营理念和方法与之适应。提出泛储木场理念下的营销思想，探讨在该理念下的用材林经营方式。根据广西大青山林区内分布于上、中、下3个坡位，胸径12～48 cm 的米老排林立木数据，用统计模型的方法拟合此经营方式下米老排的树高曲线和削度方程，给出一种实现林木生长量最大化且没有储木场损失的米老排用材林营销流程。
