Current research focussed on the assessment of metal machining process parameters and on the development of adaptive control, shows that machine performance, work-piece and tool material selections, tool life, quality...Current research focussed on the assessment of metal machining process parameters and on the development of adaptive control, shows that machine performance, work-piece and tool material selections, tool life, quality of machined surfaces, the geometry of cutting tool edges, and cutting conditions are closely related to the cutting forces. This information is of great interest to cutting tool manufactures and users alike. Over the years there have been significant developments and improvements in the equipment used to monitor such forces. In 1930 mechanical gauges were replaced by resistance strain gauges, and some 30 years later compact air gauge dynamometers were invented. Since this time intensive research has continued being directed to- wards developing new approaches to cutting force measurement. The Kistler Company, well-known manufacturer of acceleration and piezoelectrical dynamometers, has worked in this field for more than three decades, and developed very sensitive devices. While leading manufacturing research laboratories are often equipped with this technology, classical electrical strain gauges and other dynamometers of individual designs are still commonly used in industry. The present paper presents data obtained using different techniques of force measurement in metal machining processes. In particular, areas of uncertainties, illustrated through results concerning the turning process, are analysed, leading to an appraisal of the current status of these measurements and their significance.展开更多
Bunch compressor is widely used in free electron laser facility.The normalized emittance dilution comes from the high order magnet components and the misalignment of dipole.This paper describes the tolerance study for...Bunch compressor is widely used in free electron laser facility.The normalized emittance dilution comes from the high order magnet components and the misalignment of dipole.This paper describes the tolerance study for the CTF first bunch compressor.展开更多
Applications for piezoelectric effect have grown rapidly, and piezoelectric materials play important roles in countless areas of modem life. By means of twoscale method and coupled boundary layer, some new kinds of tw...Applications for piezoelectric effect have grown rapidly, and piezoelectric materials play important roles in countless areas of modem life. By means of twoscale method and coupled boundary layer, some new kinds of twoscale asymptotic expansions for solutions to the electrical potential and the displacement in quasi-periodic structure under coupled piezoelectric effect are derived, and the homogenization constants of piezoelectric materials are presented. The coupled twoscale relation between the electrical potential and the displacement is set up, and some improved asymptotic error estimates are analyzed.展开更多
ZnO nanomaterials have been shown to have novel applications in optoelectronics, energy harvesting and piezotronics, due to their coupled semiconducting and piezoelectric properties. Here a functional nanogenerator （...ZnO nanomaterials have been shown to have novel applications in optoelectronics, energy harvesting and piezotronics, due to their coupled semiconducting and piezoelectric properties. Here a functional nanogenerator （FNG） based on ZnO nanowire arrays has been fabricated, which can be employed to detect vibration in both self-powered （SP） and external-powered （EP） modes. In SP mode, the vibration responses of the FNG can be measured through converting mechanical energy directly into an electrical signal. The FNG shows consistent alternating current responses （relative error 〈 0.37%） at regular frequencies from 1 to 15 Hz. In EP mode, the current responses of FNG are significantly enhanced via the piezotronic effect. Under a forward bias of 3 V, the sensor presented a sensitivity of 3700% and an accurate measurement （relative error 〈 0.91%） of vibration frequencies in the range 0.05-15 Hz. The results show that this type of functional nanogenerator sensor can detect vibration in both SP and EP modes according to the demands of the applications.展开更多
The ultrafast photoinduced strain(UPS)resulting from the coupling of piezoelectric and photovoltaic effects in ferroelectric has been focused in the last decade,endowing them with extensive applications including ultr...The ultrafast photoinduced strain(UPS)resulting from the coupling of piezoelectric and photovoltaic effects in ferroelectric has been focused in the last decade,endowing them with extensive applications including ultrafast optical memories,sensors and actuators with strain engineering.The mechanism of screening of the depolarization field by photoinduced carriers is generally accepted for UPS in ferroelectrics,while the thermal component of the strain is usually diluted as the offset and has not been systematically confronted,leading to unnecessary confusion.Herein,both the positive and negative thermal expansion effects in composite ferroelectric epitaxial films are investigated by use of high-repetition-rate ultrafast X-ray diffraction,along with the piezoelectric and photovoltaic effects.The coupling of the positive/negative thermal effects and the piezoelectric/photovoltaic effects in ultrafast strain is evidenced and can be regulated.The opposite lattice responses due to different thermal effects of the samples with different axial ratios are observed.The maximum UPS is up to 0.24%,comparable to that of conventional ferroelectric.The interaction between the thermal and ferroelectric effects in the induced strain could promote the diversified applications with the coupling of light,heat and electricity.展开更多
基金Project supported by the Postgraduate Award of University of SouthAustralia, Australia
文摘Current research focussed on the assessment of metal machining process parameters and on the development of adaptive control, shows that machine performance, work-piece and tool material selections, tool life, quality of machined surfaces, the geometry of cutting tool edges, and cutting conditions are closely related to the cutting forces. This information is of great interest to cutting tool manufactures and users alike. Over the years there have been significant developments and improvements in the equipment used to monitor such forces. In 1930 mechanical gauges were replaced by resistance strain gauges, and some 30 years later compact air gauge dynamometers were invented. Since this time intensive research has continued being directed to- wards developing new approaches to cutting force measurement. The Kistler Company, well-known manufacturer of acceleration and piezoelectrical dynamometers, has worked in this field for more than three decades, and developed very sensitive devices. While leading manufacturing research laboratories are often equipped with this technology, classical electrical strain gauges and other dynamometers of individual designs are still commonly used in industry. The present paper presents data obtained using different techniques of force measurement in metal machining processes. In particular, areas of uncertainties, illustrated through results concerning the turning process, are analysed, leading to an appraisal of the current status of these measurements and their significance.
文摘Bunch compressor is widely used in free electron laser facility.The normalized emittance dilution comes from the high order magnet components and the misalignment of dipole.This paper describes the tolerance study for the CTF first bunch compressor.
基金supported by the National Natural Science Foundation of China(Grant Nos.10801042,11126132,and 11171257)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20104410120001)San Diego supported by China Scholarship Council from July 2012 to July 2013
文摘Applications for piezoelectric effect have grown rapidly, and piezoelectric materials play important roles in countless areas of modem life. By means of twoscale method and coupled boundary layer, some new kinds of twoscale asymptotic expansions for solutions to the electrical potential and the displacement in quasi-periodic structure under coupled piezoelectric effect are derived, and the homogenization constants of piezoelectric materials are presented. The coupled twoscale relation between the electrical potential and the displacement is set up, and some improved asymptotic error estimates are analyzed.
基金This work was supported by the National Major Research Program of China （No. 2013CB932602）, the Major Project of International Cooperation and Exchanges （No. 2012DFA50990）, National Natural Science Foundation of China （NSFC） （Nos. 51232001, 51172022, 51372020, and 51002008）, the Fundamental Research Funds for Central Universities, Program for New Century Excellent Talents in Universities, and the Program for Changjiang Scholars and Innovative Research Teams in Universities.
文摘ZnO nanomaterials have been shown to have novel applications in optoelectronics, energy harvesting and piezotronics, due to their coupled semiconducting and piezoelectric properties. Here a functional nanogenerator （FNG） based on ZnO nanowire arrays has been fabricated, which can be employed to detect vibration in both self-powered （SP） and external-powered （EP） modes. In SP mode, the vibration responses of the FNG can be measured through converting mechanical energy directly into an electrical signal. The FNG shows consistent alternating current responses （relative error 〈 0.37%） at regular frequencies from 1 to 15 Hz. In EP mode, the current responses of FNG are significantly enhanced via the piezotronic effect. Under a forward bias of 3 V, the sensor presented a sensitivity of 3700% and an accurate measurement （relative error 〈 0.91%） of vibration frequencies in the range 0.05-15 Hz. The results show that this type of functional nanogenerator sensor can detect vibration in both SP and EP modes according to the demands of the applications.
基金supported by the National Key Research and Development Program of China(2018YFA0703700 and 2017YFE0119700)the National Natural Science Foundation of China(21801013,1190524,51774034 and 51961135107)+2 种基金Beijing Natural Science Foundation(2182039)the Fundamental Research Funds for the Central Universities(FRF-IDRY-19-007 and FRF-TP-19-055A2Z)the Young Elite Scientists Sponsorship Program by CAST(20192021QNRC)。
文摘The ultrafast photoinduced strain(UPS)resulting from the coupling of piezoelectric and photovoltaic effects in ferroelectric has been focused in the last decade,endowing them with extensive applications including ultrafast optical memories,sensors and actuators with strain engineering.The mechanism of screening of the depolarization field by photoinduced carriers is generally accepted for UPS in ferroelectrics,while the thermal component of the strain is usually diluted as the offset and has not been systematically confronted,leading to unnecessary confusion.Herein,both the positive and negative thermal expansion effects in composite ferroelectric epitaxial films are investigated by use of high-repetition-rate ultrafast X-ray diffraction,along with the piezoelectric and photovoltaic effects.The coupling of the positive/negative thermal effects and the piezoelectric/photovoltaic effects in ultrafast strain is evidenced and can be regulated.The opposite lattice responses due to different thermal effects of the samples with different axial ratios are observed.The maximum UPS is up to 0.24%,comparable to that of conventional ferroelectric.The interaction between the thermal and ferroelectric effects in the induced strain could promote the diversified applications with the coupling of light,heat and electricity.
