A surface model called the fibre bundle model is proposed. This model represents a surface locally as a direct product of two curves： a base curve and a fibre curve. We introduce the fibre bundle model and then obtai...A surface model called the fibre bundle model is proposed. This model represents a surface locally as a direct product of two curves： a base curve and a fibre curve. We introduce the fibre bundle model and then obtain the Gaussian curvatures and the mean curvatures of a certain kind of fibre bundle surface models using 1-parameter groups of a linear Lie algebra as fibres. Some examples are given to verify our results.展开更多
Optical fibre sensor has the advantages of small size,light weight,anti⁃electromagnetic interference,and high measurement accuracy,which has important applications in research and industrial production.To design an op...Optical fibre sensor has the advantages of small size,light weight,anti⁃electromagnetic interference,and high measurement accuracy,which has important applications in research and industrial production.To design an optical fibre displacement sensor(OFBDS)with simple structure and high measurement accuracy,the unified model of the commonly used OFBDS structures was proposed and the feasibility of the intensity⁃modulation of multi⁃structural optical fibre bundles was analysed based on the arrangement characteristics of the fibre bundle end⁃face.The intensity⁃modulation characteristic of different fibre bundles was analysed,and the single coil coaxial fibre bundle was chosen as the fibre probe in this study.The sensor hardware system was designed.Lastly,the calibration experiment,temperature interference experiment,changes of measured plane surface area,and the dynamic experiment were conducted.Results showed that the sensor linear measurement range was about 3 mm,and the sensor system had excellent static and dynamic characteristics.展开更多
The principles for the modulus method and the percentage method are established and discussed in the part following Part Ⅰ of the series papers, in which we proposed the various algorithms of the strength method and ...The principles for the modulus method and the percentage method are established and discussed in the part following Part Ⅰ of the series papers, in which we proposed the various algorithms of the strength method and the work method. The samples of Wool/PET blended fibre bundles, the method of fibre-bundle tensile tests and the typical specific stress-extension curves from the fibre bundles with different blend ratios are the same as in Part Ⅰ. It can be found that the theoretical results estimated by the modulus and percentage methods accord with the experimental values highly though the calculations of the two methods are slightly more complex than those of the strength and work methods. Especially, using the modulus method can not only avoid the influence of the error caused by the determination of the tensile curve of no fibre breaking in stretching, Y(e), but also need not to know the tensile curves of mono-component fibre bundles in certain calculation. The latter advantage of the modulus method exists in the percentage method too, but it should adopt the improved calculation of ones.展开更多
The blend ratio and tensile properties are vital important characteristics of blended fibre bundles. Fibre-bundle tensile behaviour has been measured by means of the Sirolan-Tensor in order to derive a typical specifi...The blend ratio and tensile properties are vital important characteristics of blended fibre bundles. Fibre-bundle tensile behaviour has been measured by means of the Sirolan-Tensor in order to derive a typical specific stress — extension curve. According to the typical tensile curve, the relationships between the blend ratio and the tensile parameters are discussed and established. Two new algorithms, so-called the strength method and the work method, have been developed for the blend-ratio estimation of blended fibre bundles. The relevant blend-ratios and calculations of the two methods are defined in detail. Also, the characteristics have been explained for every calculation and compared to each others. The experimental results show that the blend ratios estimated from the theoretical methods are high coincidence with the measured results. Meanwhile, the specific stress — extension curve of blended fibre bundles depends directly on the blend ratios of the fibre bundles.展开更多
The algorithms of the strength, work, modulus and percentage methods have been introduced and discussed in Part Ⅰ and Part Ⅱ of the series papers. As the following, the percentage-function calculation and the freque...The algorithms of the strength, work, modulus and percentage methods have been introduced and discussed in Part Ⅰ and Part Ⅱ of the series papers. As the following, the percentage-function calculation and the frequency-function calculation of the definition method are defined and developed in detail. Meanwhile, the procedures to find the tensile parameters are analysed experimentally and involve “ED” being the average values of the corresponding tensile parameters of each bundle tensile curve measured; “EC” being the tensile parameters obtained from the averaged experimental tensile curve; and “TC” being the parameters of the theoretical tensile curve according to the corresponding nominal blend ratio. The theoretical and experimental results indicate that the blend ratio estimated by the definition method from wool/polyester blended fibre bundles has a high correlation with the actual blend ratio though the variables to be known in this method are the most of all the methods and there exist the difficulty to solve fibre bundle tensile behaviour without fibre broken in accuracy and that there are high correlations between the EC and TC data and the tensile parameters should be calculated using the EC method rather than the ED method with the exception of the bundle initial modulus. The relationships between blend ratios and the tensile properties of blended fibre bundles can be used to select the optimum blend ratio of blended tops or yarns.展开更多
The definition of nonlinear control sysms on fibre bundles proposed by Brockett and Willems is incomplete from the mathematical view geometric framework is proposed and a minimal realization theory is developed for no...The definition of nonlinear control sysms on fibre bundles proposed by Brockett and Willems is incomplete from the mathematical view geometric framework is proposed and a minimal realization theory is developed for nonlinear control systems on fibre bundles which is elaborated as a natural generalization of Sussmann's theory and differs essentially from Van der Schaft's approach. Limitations of realization theory given by Van der Schaft are also discussed.展开更多
There exists an Ehresmann connection on the fibred constrained sub-manifold defined by Pfaffian differential constraints. It is proved that curvature of the connection is closely related to the d-delta commutation rel...There exists an Ehresmann connection on the fibred constrained sub-manifold defined by Pfaffian differential constraints. It is proved that curvature of the connection is closely related to the d-delta commutation relation in the classical nonholonomic mechanics. It is also proved that conditions of complete integrability for Pfaffian systems in Frobenius sense are equivalent to the three requirements upon the conditional variations in the classical calculus of variations: (1) the variations belong to the constrained manifold, (2) variational operators commute with differential operators, (3) variations satisfy the Chetaev's conditions. Thus this theory verifies the conjecture or experience of researchers of mechanics on the integrability conditions in terms of variation calculus.展开更多
In this article,we give a generalization of δ-twisted homology introduced by Jingyan Li,Vladimir Vershinin and Jie Wu,called Δ-twisted homology,which enriches the theory of δ-(co)homology introduced by Alexander Gr...In this article,we give a generalization of δ-twisted homology introduced by Jingyan Li,Vladimir Vershinin and Jie Wu,called Δ-twisted homology,which enriches the theory of δ-(co)homology introduced by Alexander Grigor’yan,Yuri Muranov and Shing-Tung Yau.We show that the Mayer-Vietoris sequence theorem holds for Δ-twisted homology.Applying the Δ-twisted ideas to Cartesian products,we introduce the notion of Δ-twisted Cartesian product on simplicial sets,which generalizes the classical work of Barratt,Gugenheim and Moore on twisted Cartesian products of simplicial sets.Under certain hypothesis,we show that the coordinate projection of Δ-twisted Cartesian product admits a fibre bundle structure.展开更多
文摘A surface model called the fibre bundle model is proposed. This model represents a surface locally as a direct product of two curves： a base curve and a fibre curve. We introduce the fibre bundle model and then obtain the Gaussian curvatures and the mean curvatures of a certain kind of fibre bundle surface models using 1-parameter groups of a linear Lie algebra as fibres. Some examples are given to verify our results.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51775260)the Qinglan Project of Jiangsu Province(2017)of China and the Funds of Nanjing Institute of Technology(Grant No.CKJA201801).
文摘Optical fibre sensor has the advantages of small size,light weight,anti⁃electromagnetic interference,and high measurement accuracy,which has important applications in research and industrial production.To design an optical fibre displacement sensor(OFBDS)with simple structure and high measurement accuracy,the unified model of the commonly used OFBDS structures was proposed and the feasibility of the intensity⁃modulation of multi⁃structural optical fibre bundles was analysed based on the arrangement characteristics of the fibre bundle end⁃face.The intensity⁃modulation characteristic of different fibre bundles was analysed,and the single coil coaxial fibre bundle was chosen as the fibre probe in this study.The sensor hardware system was designed.Lastly,the calibration experiment,temperature interference experiment,changes of measured plane surface area,and the dynamic experiment were conducted.Results showed that the sensor linear measurement range was about 3 mm,and the sensor system had excellent static and dynamic characteristics.
文摘The principles for the modulus method and the percentage method are established and discussed in the part following Part Ⅰ of the series papers, in which we proposed the various algorithms of the strength method and the work method. The samples of Wool/PET blended fibre bundles, the method of fibre-bundle tensile tests and the typical specific stress-extension curves from the fibre bundles with different blend ratios are the same as in Part Ⅰ. It can be found that the theoretical results estimated by the modulus and percentage methods accord with the experimental values highly though the calculations of the two methods are slightly more complex than those of the strength and work methods. Especially, using the modulus method can not only avoid the influence of the error caused by the determination of the tensile curve of no fibre breaking in stretching, Y(e), but also need not to know the tensile curves of mono-component fibre bundles in certain calculation. The latter advantage of the modulus method exists in the percentage method too, but it should adopt the improved calculation of ones.
文摘The blend ratio and tensile properties are vital important characteristics of blended fibre bundles. Fibre-bundle tensile behaviour has been measured by means of the Sirolan-Tensor in order to derive a typical specific stress — extension curve. According to the typical tensile curve, the relationships between the blend ratio and the tensile parameters are discussed and established. Two new algorithms, so-called the strength method and the work method, have been developed for the blend-ratio estimation of blended fibre bundles. The relevant blend-ratios and calculations of the two methods are defined in detail. Also, the characteristics have been explained for every calculation and compared to each others. The experimental results show that the blend ratios estimated from the theoretical methods are high coincidence with the measured results. Meanwhile, the specific stress — extension curve of blended fibre bundles depends directly on the blend ratios of the fibre bundles.
文摘The algorithms of the strength, work, modulus and percentage methods have been introduced and discussed in Part Ⅰ and Part Ⅱ of the series papers. As the following, the percentage-function calculation and the frequency-function calculation of the definition method are defined and developed in detail. Meanwhile, the procedures to find the tensile parameters are analysed experimentally and involve “ED” being the average values of the corresponding tensile parameters of each bundle tensile curve measured; “EC” being the tensile parameters obtained from the averaged experimental tensile curve; and “TC” being the parameters of the theoretical tensile curve according to the corresponding nominal blend ratio. The theoretical and experimental results indicate that the blend ratio estimated by the definition method from wool/polyester blended fibre bundles has a high correlation with the actual blend ratio though the variables to be known in this method are the most of all the methods and there exist the difficulty to solve fibre bundle tensile behaviour without fibre broken in accuracy and that there are high correlations between the EC and TC data and the tensile parameters should be calculated using the EC method rather than the ED method with the exception of the bundle initial modulus. The relationships between blend ratios and the tensile properties of blended fibre bundles can be used to select the optimum blend ratio of blended tops or yarns.
文摘The definition of nonlinear control sysms on fibre bundles proposed by Brockett and Willems is incomplete from the mathematical view geometric framework is proposed and a minimal realization theory is developed for nonlinear control systems on fibre bundles which is elaborated as a natural generalization of Sussmann's theory and differs essentially from Van der Schaft's approach. Limitations of realization theory given by Van der Schaft are also discussed.
文摘There exists an Ehresmann connection on the fibred constrained sub-manifold defined by Pfaffian differential constraints. It is proved that curvature of the connection is closely related to the d-delta commutation relation in the classical nonholonomic mechanics. It is also proved that conditions of complete integrability for Pfaffian systems in Frobenius sense are equivalent to the three requirements upon the conditional variations in the classical calculus of variations: (1) the variations belong to the constrained manifold, (2) variational operators commute with differential operators, (3) variations satisfy the Chetaev's conditions. Thus this theory verifies the conjecture or experience of researchers of mechanics on the integrability conditions in terms of variation calculus.
基金Supported by NSFC(Grant No.11971144)High-level Scientific Research Foundation of Hebei Province+1 种基金the start-up research fund from BIMSAsupported by Postgraduate Innovation Funding Project of Hebei Province(Grant No.CXZZBS2022073)。
文摘In this article,we give a generalization of δ-twisted homology introduced by Jingyan Li,Vladimir Vershinin and Jie Wu,called Δ-twisted homology,which enriches the theory of δ-(co)homology introduced by Alexander Grigor’yan,Yuri Muranov and Shing-Tung Yau.We show that the Mayer-Vietoris sequence theorem holds for Δ-twisted homology.Applying the Δ-twisted ideas to Cartesian products,we introduce the notion of Δ-twisted Cartesian product on simplicial sets,which generalizes the classical work of Barratt,Gugenheim and Moore on twisted Cartesian products of simplicial sets.Under certain hypothesis,we show that the coordinate projection of Δ-twisted Cartesian product admits a fibre bundle structure.
