Single switch is the most common and the largest number of switch products in China's railway switches. Based on the composition and classification of single turnout, this paper introduces the static inspection sy...Single switch is the most common and the largest number of switch products in China's railway switches. Based on the composition and classification of single turnout, this paper introduces the static inspection system, inspection tools, items, methods, technical requirements of static inspection and management standard of static inspection geometric dimensions.展开更多
We demonstrate the fabrication of a single electron transistor device based on a single ultra-small silicon quantum dot connected to a gold break junction with a nanometer scale separation. The gold break junction is ...We demonstrate the fabrication of a single electron transistor device based on a single ultra-small silicon quantum dot connected to a gold break junction with a nanometer scale separation. The gold break junction is created through a controllable electromigration process and the individual silicon quantum dot in the junction is deter- mined to be a Si 170 cluster. Differential conductance as a function of the bias and gate voltage clearly shows the Coulomb diamond which confirms that the transport is dominated by a single silicon quantum dot. It is found that the charging energy can be as large as 300meV, which is a result of the large capacitance of a small silicon quantum dot （-1.8 nm）. This large Coulomb interaction can potentially enable a single electron transistor to work at room temperature. The level spacing of the excited state can be as large as 10meV, which enables us to manipulate individual spin via an external magnetic field. The resulting Zeeman splitting is measured and the g factor of 2.3 is obtained, suggesting relatively weak electron-electron interaction in the silicon quantum dot which is beneficial for spin coherence time.展开更多
The various configurations of multilevel inverter involve the use of more numbers of switching devices, energy storage devices and/or unidirectional devices. Each switching unit necessitates the add-on driver circuit ...The various configurations of multilevel inverter involve the use of more numbers of switching devices, energy storage devices and/or unidirectional devices. Each switching unit necessitates the add-on driver circuit for proper functionality. Cascaded H-Bridge Multilevel Inverter requires overlapped switching pulses for the switching devices in positive and negative arms of the bridge which may lead to short circuit during the device failure. This work addresses the problems in different configurations of multilevel inverter by using reduced number of switching and energy storage devices and driver circuits. In the present approach Single Switch is used for each stair case positive output and single H-Bridge for phase reversal. Driver circuits are reduced by using the property of body diode of the MOSFET. Switching pulses are generated by Arduino Development Board. The circuit is simulated using Matlab. More so, through experimental means, it is physically tested and results are analyzed for the 5-step inverter and thereby simulation is fully validated. Consequently, cycloconverter operation of the circuit is simulated using Matlab. Moreover, half bridge configuration of the multilevel inverter is also analyzed for high frequency induction heating applications.展开更多
Electro-optic active metasurfaces have attracted attention due to their ability to electronically control optical wavefronts with unprecedented spatiotemporal resolutions.In most studies,such devices require gate arra...Electro-optic active metasurfaces have attracted attention due to their ability to electronically control optical wavefronts with unprecedented spatiotemporal resolutions.In most studies,such devices require gate arrays composed of a large number of independently-controllable local gate electrodes that address the local scattering response of individual metaatoms.Although this approach in principle enables arbitrary wavefront control,the complicated driving mechanism and low optical efficiency have been hindering its practical applications.In this work,we demonstrate an active beam switching device that provides highly directional beam profiles and significant and uniform optical efficiencies across diffraction orders separated by a large deflection angle.The device operates with only a single-gate bias applied to monolayer graphene,modulating its optical conductivity to control the optical efficiency of the device.The key performance metrics,the absolute and the relative efficiency,which are defined as the scattered power toward a certain angleθnormalized by the incident power and the net scattered power from the metasurface,respectively,are maximized by a genetic algorithm.Experimentally,the metasurface achieves 57°of active beam switching from the 0th to the−1st order diffraction,with absolute efficiencies of 0.084 and 0.078 and relative efficiencies of 0.765 and 0.836,respectively.Furthermore,an analytical framework using nonlocal quasinormal mode expansion provides deeper insight into the operating mechanism of active beam switching.Finally,we discuss the performance limitations of this design platform and provide insights into potential improvements.展开更多
Electro-optic active metasurfaces have attracted attention due to their ability to electronically control optical wavefronts with unprecedented spatiotemporal resolutions.In most studies,such devices require gate arra...Electro-optic active metasurfaces have attracted attention due to their ability to electronically control optical wavefronts with unprecedented spatiotemporal resolutions.In most studies,such devices require gate arrays composed of a large number of independently-controllable local gate electrodes that address the local scattering response of individual metaatoms.Although this approach in principle enables arbitrary wavefront control,the complicated driving mechanism and low optical efficiency have been hindering its practical applications.In this work,we demonstrate an active beam switching device that provides highly directional beam profiles and significant and uniform optical efficiencies across diffraction orders separated by a large deflection angle.The device operates with only a single-gate bias applied to monolayer graphene,modulating its optical conductivity to control the optical efficiency of the device.The key performance metrics,the absolute and the relative efficiency,which are defined as the scattered power toward a certain angleθnormalized by the incident power and the net scattered power from the metasurface,respectively,are maximized by a genetic algorithm.Experimentally,the metasurface achieves 57°of active beam switching from the 0th to the−1st order diffraction,with absolute efficiencies of 0.084 and 0.078 and relative efficiencies of 0.765 and 0.836,respectively.Furthermore,an analytical framework using nonlocal quasinormal mode expansion provides deeper insight into the operating mechanism of active beam switching.Finally,we discuss the performance limitations of this design platform and provide insights into potential improvements.展开更多
文摘Single switch is the most common and the largest number of switch products in China's railway switches. Based on the composition and classification of single turnout, this paper introduces the static inspection system, inspection tools, items, methods, technical requirements of static inspection and management standard of static inspection geometric dimensions.
基金Supported by the National Key Research and Development Program of China under Grant No 2017YFA0303200the National Natural Science Foundation of China under Grant Nos U1732273,U1732159,91421109,91622115,11522432,11574217 and 61774133the Natural Science Foundation of Jiangsu Province under Grant No BK20160659
文摘We demonstrate the fabrication of a single electron transistor device based on a single ultra-small silicon quantum dot connected to a gold break junction with a nanometer scale separation. The gold break junction is created through a controllable electromigration process and the individual silicon quantum dot in the junction is deter- mined to be a Si 170 cluster. Differential conductance as a function of the bias and gate voltage clearly shows the Coulomb diamond which confirms that the transport is dominated by a single silicon quantum dot. It is found that the charging energy can be as large as 300meV, which is a result of the large capacitance of a small silicon quantum dot （-1.8 nm）. This large Coulomb interaction can potentially enable a single electron transistor to work at room temperature. The level spacing of the excited state can be as large as 10meV, which enables us to manipulate individual spin via an external magnetic field. The resulting Zeeman splitting is measured and the g factor of 2.3 is obtained, suggesting relatively weak electron-electron interaction in the silicon quantum dot which is beneficial for spin coherence time.
文摘The various configurations of multilevel inverter involve the use of more numbers of switching devices, energy storage devices and/or unidirectional devices. Each switching unit necessitates the add-on driver circuit for proper functionality. Cascaded H-Bridge Multilevel Inverter requires overlapped switching pulses for the switching devices in positive and negative arms of the bridge which may lead to short circuit during the device failure. This work addresses the problems in different configurations of multilevel inverter by using reduced number of switching and energy storage devices and driver circuits. In the present approach Single Switch is used for each stair case positive output and single H-Bridge for phase reversal. Driver circuits are reduced by using the property of body diode of the MOSFET. Switching pulses are generated by Arduino Development Board. The circuit is simulated using Matlab. More so, through experimental means, it is physically tested and results are analyzed for the 5-step inverter and thereby simulation is fully validated. Consequently, cycloconverter operation of the circuit is simulated using Matlab. Moreover, half bridge configuration of the multilevel inverter is also analyzed for high frequency induction heating applications.
基金supported by the National Research Foundation of Korea(NRF)grants(NRF-2022R1A2C2092095,RS-2024-00416583,RS-2024-00414119,RS2024-00452558)funded by the Korea government(MSIT),and Samsung Research Funding and Incubation Center of Samsung Electronics grant(SRFCIT1702-14)+1 种基金supported by the Ministry of Trade,Industry&Energy(MOTIE)(1415180303)the Korea Semiconductor Research Consortium(KSRC)(20019357).
文摘Electro-optic active metasurfaces have attracted attention due to their ability to electronically control optical wavefronts with unprecedented spatiotemporal resolutions.In most studies,such devices require gate arrays composed of a large number of independently-controllable local gate electrodes that address the local scattering response of individual metaatoms.Although this approach in principle enables arbitrary wavefront control,the complicated driving mechanism and low optical efficiency have been hindering its practical applications.In this work,we demonstrate an active beam switching device that provides highly directional beam profiles and significant and uniform optical efficiencies across diffraction orders separated by a large deflection angle.The device operates with only a single-gate bias applied to monolayer graphene,modulating its optical conductivity to control the optical efficiency of the device.The key performance metrics,the absolute and the relative efficiency,which are defined as the scattered power toward a certain angleθnormalized by the incident power and the net scattered power from the metasurface,respectively,are maximized by a genetic algorithm.Experimentally,the metasurface achieves 57°of active beam switching from the 0th to the−1st order diffraction,with absolute efficiencies of 0.084 and 0.078 and relative efficiencies of 0.765 and 0.836,respectively.Furthermore,an analytical framework using nonlocal quasinormal mode expansion provides deeper insight into the operating mechanism of active beam switching.Finally,we discuss the performance limitations of this design platform and provide insights into potential improvements.
基金supported by the National Research Foundation of Korea(NRF)grants(NRF-2022R1A2C2092095,RS-2024-00416583,RS-2024-00414119,RS-2024-00452558)funded by the Korea government(MSIT)Samsung Research Funding and Incubation Center of Samsung Electronics grant(SRFC-IT1702-14)+1 种基金This research was also supported by the Ministry of Trade,Industry&Energy(MOTIE)(1415180303)the Korea Semiconductor Research Consortium(KSRC)(20019357).
文摘Electro-optic active metasurfaces have attracted attention due to their ability to electronically control optical wavefronts with unprecedented spatiotemporal resolutions.In most studies,such devices require gate arrays composed of a large number of independently-controllable local gate electrodes that address the local scattering response of individual metaatoms.Although this approach in principle enables arbitrary wavefront control,the complicated driving mechanism and low optical efficiency have been hindering its practical applications.In this work,we demonstrate an active beam switching device that provides highly directional beam profiles and significant and uniform optical efficiencies across diffraction orders separated by a large deflection angle.The device operates with only a single-gate bias applied to monolayer graphene,modulating its optical conductivity to control the optical efficiency of the device.The key performance metrics,the absolute and the relative efficiency,which are defined as the scattered power toward a certain angleθnormalized by the incident power and the net scattered power from the metasurface,respectively,are maximized by a genetic algorithm.Experimentally,the metasurface achieves 57°of active beam switching from the 0th to the−1st order diffraction,with absolute efficiencies of 0.084 and 0.078 and relative efficiencies of 0.765 and 0.836,respectively.Furthermore,an analytical framework using nonlocal quasinormal mode expansion provides deeper insight into the operating mechanism of active beam switching.Finally,we discuss the performance limitations of this design platform and provide insights into potential improvements.
