In order to meet the technical requirements of grinding the circumferential cutting edge of indexable inserts, thermo-mechanical properties of bowl-shaped grinding wheel in high speed grinding process and the influenc...In order to meet the technical requirements of grinding the circumferential cutting edge of indexable inserts, thermo-mechanical properties of bowl-shaped grinding wheel in high speed grinding process and the influence of dimension variations of the grinding wheel on machining accuracy were investigated. Firstly, the variation trends of the dimension due to centrifugal force generated in different wheel speeds were studied and the effect of stress stiffening and spin softening was presented. Triangular heat flux distribution model was adopted to determine temperature distribution in grinding process. Temperature field cloud pictures were obtained by the finite element software. Then, dimension variation trends of wheel structure were acquired by considering the thermo-mechanical characteristic under combined action of centrifugal force and grinding heat at different speeds. A method of online dynamic monitoring and automatic compensation for dimension error of indexable insert was proposed. By experimental verification, the precision of the inserts satisfies the requirement of processing.展开更多
As a preliminary step in the nonlinear design of shape memory alloy（SMA） composite structures,the force-displacement characteristics of the SMA layer are studied.The bilinear hysteretic model is adopted to describe ...As a preliminary step in the nonlinear design of shape memory alloy（SMA） composite structures,the force-displacement characteristics of the SMA layer are studied.The bilinear hysteretic model is adopted to describe the constitutive relationship of SMA material.Under the assumption that there is no point of SMA layer finishing martensitic phase transformation during the loading and unloading process,the generalized restoring force generated by SMA layer is deduced for the case that the simply supported beam vibrates in its first mode.The generalized force is expressed as piecewise-nonlinear hysteretic function of the beam transverse displacement.Furthermore the energy dissipated by SMA layer during one period is obtained by integration,then its dependencies are discussed on the vibration amplitude and the SMA＇s strain（Ms-Strain） value at the beginning of martensitic phase transformation.It is shown that SMA＇s energy dissipating capacity is proportional to the stiffness difference of bilinear model and nonlinearly dependent on Ms-Strain.The increasing rate of the dissipating capacity gradually reduces with the amplitude increasing.The condition corresponding to the maximum dissipating capacity is deduced for given value of the vibration amplitude.The obtained results are helpful for designing beams laminated with shape memory alloys.展开更多
The existence of rolling deformation area in the rolling mill system is the main characteristic which dis- tinguishes the other machinery. In order to analyze the dynamic property of roll system＇s flexural deformatio...The existence of rolling deformation area in the rolling mill system is the main characteristic which dis- tinguishes the other machinery. In order to analyze the dynamic property of roll system＇s flexural deformation, it is necessary to consider the transverse periodic movement of stock in the rolling deformation area which is caused by the flexural deformation movement of roll system simul- taneously. Therefore, the displacement field of roll system and flow of metal in the deformation area is described by kinematic analysis in the dynamic system. Through intro- ducing the lateral displacement function of metal in the deformation area, the dynamic variation of per unit width rolling force can be determined at the same time. Then the coupling law caused by the co-effect of rigid movement and flexural deformation of the system structural elements is determined. Furthermore, a multi-parameter coupling dynamic model of the roll system and stock is established by the principle of virtual work. More explicitly, the cou- pled motion modal analysis was made for the roll system. Meanwhile, the analytical solutions for the flexural defor- mation movement＇s mode shape functions of rolls are discussed. In addition, the dynamic characteristic of the lateral flow of metal in the rolling deformation area has been analyzed at the same time. The establishment ofdynamic lateral displacement function of metal in the deformation area makes the foundation for analyzing the coupling law between roll system and rolling deformation area, and provides a theoretical basis for the realization of the dynamic shape control of steel strip.展开更多
Shape is an important quality index of cold rolling strip. Up to now, many problems in the shape control domain have not been solved satisfactorily, and a review on the research progress in the shape control domain ca...Shape is an important quality index of cold rolling strip. Up to now, many problems in the shape control domain have not been solved satisfactorily, and a review on the research progress in the shape control domain can help to seek new breakthrough directions. In the past 10 years, researches and applications of shape control models, shape control means, shape detection technology, and shape con- trol system have achieved significant progress. In the aspect of shape control models, the researches in the past improve the accuracy, speed and robustness of the models. The intelligentization of shape control models should be strengthened in the future. In the aspect of the shape control means, the researches in the past focus on the roll opti- mization, mill type selection, process optimization, local strip shape control, edge drop control, and so on. In the future, more attention should be paid to the coordination control of both strip shape and other quality indexes, and the refinement of control objective should be strengthened. In the aspects of shape detection technology and shape control system, some new types of shape detection meters and shape control systems are developed and have successfully indus- trial applications. In the future, the standardization of shape detection technology and shape control system should be promoted to solve the problem of compatibility. In general,the four expected development trends of shape control for cold roiling strip in the future are intelligentization, coordi- nation, refinement, and standardization. The proposed research provides new breakthrough directions for improv- ing shape quality.展开更多
In this paper, electromagnetic poly（3,4-ethylenedioxythiophene）/γ-Fe2O3 （PEDOT/γ-Fe2O3 ） micro-bowls, 1-2 gm in diameter, were prepared by a simple environment-friendly process. In this method, the aqueous solu...In this paper, electromagnetic poly（3,4-ethylenedioxythiophene）/γ-Fe2O3 （PEDOT/γ-Fe2O3 ） micro-bowls, 1-2 gm in diameter, were prepared by a simple environment-friendly process. In this method, the aqueous solution of cetyltrimethylammonium bromide （CTAB） instead of any organic solvent was used. FeC13 acted as a source of FeIII for the formation of γ-Fe2O3 and as an oxidant for the polymerization of 3,4-ethylenedioxythiophene （EDOT）. The bowl-shaped morphology of PEDOT/γ-Fe2O3 composites was strongly influenced by the concentration of CTAB, FeCl2, ammonia solution and the reaction temperature. The saturation magnetization of PEDOT/γ-Fe2O3 micro-bowls increased with the increase of FeC12 concentration and reached 6.20 AmE/kg at the FeCl2 concentration of 0.30 mol/L. The conductivity of the PEDOT/γ-Fe2O3 composites was in the range of 101 S/cm. The electrical and magnetic sources of PEDOT/γ-Fe2O3 micro-bowls were confirmed by SEM-EDX, TEM, XRD and XPS spectra. And the possible formation mechanism of PEDOT//7：Fe203 was proposed.展开更多
Contact exposure is expected to occur in conventional lithography, and can be a source of process deviations （such as shrinking and distortion of templates） during reactive ion etching and inductively coupled plasma...Contact exposure is expected to occur in conventional lithography, and can be a source of process deviations （such as shrinking and distortion of templates） during reactive ion etching and inductively coupled plasma etching, as these deviations are induced by ion bombardment. This typically results in undesired sidewall effects, such as lower sidewall angles. Here we report a novel hanging bowlshaped lithography mask that can effectively minimize sidewall effects in lithography applications. As a test case, standard silicon carbide pillars with vertical sidewalls are fabricated using this mask. The mask could be used for fabrication of high-aspect-ratio structures with ultra-violet lithography.展开更多
基金Project(2010ZX04001-162)supported by the National Science and Technology Major Project of China
文摘In order to meet the technical requirements of grinding the circumferential cutting edge of indexable inserts, thermo-mechanical properties of bowl-shaped grinding wheel in high speed grinding process and the influence of dimension variations of the grinding wheel on machining accuracy were investigated. Firstly, the variation trends of the dimension due to centrifugal force generated in different wheel speeds were studied and the effect of stress stiffening and spin softening was presented. Triangular heat flux distribution model was adopted to determine temperature distribution in grinding process. Temperature field cloud pictures were obtained by the finite element software. Then, dimension variation trends of wheel structure were acquired by considering the thermo-mechanical characteristic under combined action of centrifugal force and grinding heat at different speeds. A method of online dynamic monitoring and automatic compensation for dimension error of indexable insert was proposed. By experimental verification, the precision of the inserts satisfies the requirement of processing.
基金supported by the National Natural Science Foundation of China (10872142 and 10632040)New Century Excellent Talents in University of China (NCET-05-0247)the Key Program of the Natural Science Foundation of Tianjin (09JCZDJ26800)
文摘As a preliminary step in the nonlinear design of shape memory alloy（SMA） composite structures,the force-displacement characteristics of the SMA layer are studied.The bilinear hysteretic model is adopted to describe the constitutive relationship of SMA material.Under the assumption that there is no point of SMA layer finishing martensitic phase transformation during the loading and unloading process,the generalized restoring force generated by SMA layer is deduced for the case that the simply supported beam vibrates in its first mode.The generalized force is expressed as piecewise-nonlinear hysteretic function of the beam transverse displacement.Furthermore the energy dissipated by SMA layer during one period is obtained by integration,then its dependencies are discussed on the vibration amplitude and the SMA＇s strain（Ms-Strain） value at the beginning of martensitic phase transformation.It is shown that SMA＇s energy dissipating capacity is proportional to the stiffness difference of bilinear model and nonlinearly dependent on Ms-Strain.The increasing rate of the dissipating capacity gradually reduces with the amplitude increasing.The condition corresponding to the maximum dissipating capacity is deduced for given value of the vibration amplitude.The obtained results are helpful for designing beams laminated with shape memory alloys.
基金Supported by National Natural Science Foundation of China(Grant No.51375424)
文摘The existence of rolling deformation area in the rolling mill system is the main characteristic which dis- tinguishes the other machinery. In order to analyze the dynamic property of roll system＇s flexural deformation, it is necessary to consider the transverse periodic movement of stock in the rolling deformation area which is caused by the flexural deformation movement of roll system simul- taneously. Therefore, the displacement field of roll system and flow of metal in the deformation area is described by kinematic analysis in the dynamic system. Through intro- ducing the lateral displacement function of metal in the deformation area, the dynamic variation of per unit width rolling force can be determined at the same time. Then the coupling law caused by the co-effect of rigid movement and flexural deformation of the system structural elements is determined. Furthermore, a multi-parameter coupling dynamic model of the roll system and stock is established by the principle of virtual work. More explicitly, the cou- pled motion modal analysis was made for the roll system. Meanwhile, the analytical solutions for the flexural defor- mation movement＇s mode shape functions of rolls are discussed. In addition, the dynamic characteristic of the lateral flow of metal in the rolling deformation area has been analyzed at the same time. The establishment ofdynamic lateral displacement function of metal in the deformation area makes the foundation for analyzing the coupling law between roll system and rolling deformation area, and provides a theoretical basis for the realization of the dynamic shape control of steel strip.
基金Supported by National Key Technology Support Program of China (Grant No. 2011BAF15B00)Hebei Provincial Natural Science Foundation of China (Grant No. E2016203482)+1 种基金Hebei Provincial Science and Technology Research Foundation of China (Grant No. ZD2014034)Youth Independent Research Program of Yanshan University of China (Grant No. 14LGA003)
文摘Shape is an important quality index of cold rolling strip. Up to now, many problems in the shape control domain have not been solved satisfactorily, and a review on the research progress in the shape control domain can help to seek new breakthrough directions. In the past 10 years, researches and applications of shape control models, shape control means, shape detection technology, and shape con- trol system have achieved significant progress. In the aspect of shape control models, the researches in the past improve the accuracy, speed and robustness of the models. The intelligentization of shape control models should be strengthened in the future. In the aspect of the shape control means, the researches in the past focus on the roll opti- mization, mill type selection, process optimization, local strip shape control, edge drop control, and so on. In the future, more attention should be paid to the coordination control of both strip shape and other quality indexes, and the refinement of control objective should be strengthened. In the aspects of shape detection technology and shape control system, some new types of shape detection meters and shape control systems are developed and have successfully indus- trial applications. In the future, the standardization of shape detection technology and shape control system should be promoted to solve the problem of compatibility. In general,the four expected development trends of shape control for cold roiling strip in the future are intelligentization, coordi- nation, refinement, and standardization. The proposed research provides new breakthrough directions for improv- ing shape quality.
基金financially supported by the National Natural Science Foundation of China (No.50973098)National Science and Technology Support Program (No.2012BAB15B02)the New Zealand Foundation for Science and Technology (contract No.UOAX0806)
文摘In this paper, electromagnetic poly（3,4-ethylenedioxythiophene）/γ-Fe2O3 （PEDOT/γ-Fe2O3 ） micro-bowls, 1-2 gm in diameter, were prepared by a simple environment-friendly process. In this method, the aqueous solution of cetyltrimethylammonium bromide （CTAB） instead of any organic solvent was used. FeC13 acted as a source of FeIII for the formation of γ-Fe2O3 and as an oxidant for the polymerization of 3,4-ethylenedioxythiophene （EDOT）. The bowl-shaped morphology of PEDOT/γ-Fe2O3 composites was strongly influenced by the concentration of CTAB, FeCl2, ammonia solution and the reaction temperature. The saturation magnetization of PEDOT/γ-Fe2O3 micro-bowls increased with the increase of FeC12 concentration and reached 6.20 AmE/kg at the FeCl2 concentration of 0.30 mol/L. The conductivity of the PEDOT/γ-Fe2O3 composites was in the range of 101 S/cm. The electrical and magnetic sources of PEDOT/γ-Fe2O3 micro-bowls were confirmed by SEM-EDX, TEM, XRD and XPS spectra. And the possible formation mechanism of PEDOT//7：Fe203 was proposed.
基金Acknowledgements This research was supported by tile National Natural Science Foundation of China （Grant No. 10974037）, the CAS Strategy Pilot program （Grant No. XAD 09020300）, and the National Basic Research Program of China （Grant No. 2010CB934102）.
文摘Contact exposure is expected to occur in conventional lithography, and can be a source of process deviations （such as shrinking and distortion of templates） during reactive ion etching and inductively coupled plasma etching, as these deviations are induced by ion bombardment. This typically results in undesired sidewall effects, such as lower sidewall angles. Here we report a novel hanging bowlshaped lithography mask that can effectively minimize sidewall effects in lithography applications. As a test case, standard silicon carbide pillars with vertical sidewalls are fabricated using this mask. The mask could be used for fabrication of high-aspect-ratio structures with ultra-violet lithography.
