The Experts below are selected from a list of 21 Experts worldwide ranked by ideXlab platform
Feng Xu - One of the best experts on this subject based on the ideXlab platform.
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automatic wire clamp for portable short Circuit Ground wire
2012Co-Authors: Zhihao Lu, Ming Fu, Yongbao Zhou, Dacheng Wang, Qin Yu, Da Hu, Jianbing Yang, Ye Cai, Wei Zhu, Feng XuAbstract:The invention discloses an automatic wire clamp for a portable short-Circuit Ground wire. The automatic wire clamp is easy and convenient to operate and wide in application range. The automatic wire clamp comprises an operating rod, a static bracket, a connecting shaft, a transmission rack, a pawl, a pawl spring and a movable wire clamp, wherein the transmission rack is connected to the front end of the connecting shaft; the pawl can be meshed with a tooth tip on the outer surface of the connecting shaft; the pawl spring is arranged between the static bracket and the pawl; and the movable wire clamp is connected to the static bracket. A fixed wire clamp is arranged on one side of the front part of the static bracket. An intermediate gear meshed with the transmission rack is also arranged in an inner cavity of the static bracket. The movable wire clamp comprises a middle opening part corresponding to the fixed wire clamp and a mounting part movably arranged on the static bracket. A rack meshed with the intermediate gear is arranged on the outer end face of the mounting part. The front end of the operating rod is connected with the connecting shaft through a limiting cam. A rib is arranged on the surface of an inner cavity on the rear part of the static bracket to stop the limiting cam continuing rotating when the high surface of the limiting cam rotates to the position of the rib. A resetting spring is connected between the fixed wire clamp and the movable wire clamp.
Jed D Whittaker - One of the best experts on this subject based on the ideXlab platform.
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sideband cooling of micromechanical motion to the quantum Ground state
Nature, 2011Co-Authors: John Teufel, Tobias Donner, Jennifer W Harlow, Mark Allman, Katarina Cicak, A J Sirois, Jed D WhittakerAbstract:It has been a long-standing goal in the field of cavity optomechanics to cool down a mechanical resonator to its motional quantum Ground state by using light. Teufel et al. have now achieved just that with a recently developed system in which a drum-like flexible aluminium membrane is incorporated in a superconducting Circuit. Ground-state cooling of a mechanical resonator was demonstrated for the first time last year in a different type of device, but the quantum states in this new device should be much longer lived, allowing direct tests of fundamental principles of quantum mechanics. As a first step, the authors perform a quantum-limited position measurement that is only a factor of about five away from the Heisenberg limit. The advent of laser cooling techniques revolutionized the study of many atomic-scale systems, fuelling progress towards quantum computing with trapped ions1 and generating new states of matter with Bose–Einstein condensates2. Analogous cooling techniques3,4 can provide a general and flexible method of preparing macroscopic objects in their motional Ground state. Cavity optomechanical or electromechanical systems achieve sideband cooling through the strong interaction between light and motion5,6,7,8,9,10,11,12,13,14,15. However, entering the quantum regime—in which a system has less than a single quantum of motion—has been difficult because sideband cooling has not sufficiently overwhelmed the coupling of low-frequency mechanical systems to their hot environments. Here we demonstrate sideband cooling of an approximately 10-MHz micromechanical oscillator to the quantum Ground state. This achievement required a large electromechanical interaction, which was obtained by embedding a micromechanical membrane into a superconducting microwave resonant Circuit. To verify the cooling of the membrane motion to a phonon occupation of 0.34 ± 0.05 phonons, we perform a near-Heisenberg-limited position measurement3 within (5.1 ± 0.4)h/2π, where h is Planck’s constant. Furthermore, our device exhibits strong coupling, allowing coherent exchange of microwave photons and mechanical phonons16. Simultaneously achieving strong coupling, Ground state preparation and efficient measurement sets the stage for rapid advances in the control and detection of non-classical states of motion17,18, possibly even testing quantum theory itself in the unexplored region of larger size and mass19. Because mechanical oscillators can couple to light of any frequency, they could also serve as a unique intermediary for transferring quantum information between microwave and optical domains20.
Zhihao Lu - One of the best experts on this subject based on the ideXlab platform.
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automatic wire clamp for portable short Circuit Ground wire
2012Co-Authors: Zhihao Lu, Ming Fu, Yongbao Zhou, Dacheng Wang, Qin Yu, Da Hu, Jianbing Yang, Ye Cai, Wei Zhu, Feng XuAbstract:The invention discloses an automatic wire clamp for a portable short-Circuit Ground wire. The automatic wire clamp is easy and convenient to operate and wide in application range. The automatic wire clamp comprises an operating rod, a static bracket, a connecting shaft, a transmission rack, a pawl, a pawl spring and a movable wire clamp, wherein the transmission rack is connected to the front end of the connecting shaft; the pawl can be meshed with a tooth tip on the outer surface of the connecting shaft; the pawl spring is arranged between the static bracket and the pawl; and the movable wire clamp is connected to the static bracket. A fixed wire clamp is arranged on one side of the front part of the static bracket. An intermediate gear meshed with the transmission rack is also arranged in an inner cavity of the static bracket. The movable wire clamp comprises a middle opening part corresponding to the fixed wire clamp and a mounting part movably arranged on the static bracket. A rack meshed with the intermediate gear is arranged on the outer end face of the mounting part. The front end of the operating rod is connected with the connecting shaft through a limiting cam. A rib is arranged on the surface of an inner cavity on the rear part of the static bracket to stop the limiting cam continuing rotating when the high surface of the limiting cam rotates to the position of the rib. A resetting spring is connected between the fixed wire clamp and the movable wire clamp.
Surya Santoso - One of the best experts on this subject based on the ideXlab platform.
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Estimating zero-sequence impedance of three-terminal transmission line and Thevenin impedance using relay measurement data
Protection and Control of Modern Power Systems, 2018Co-Authors: Sundaravaradan Navalpakkam Ananthan, Surya SantosoAbstract:Current and voltage waveforms recorded by intelligent electronic devices (IEDs) are more useful than just performing post-fault analysis. The objective of this paper is to present techniques to estimate the zero-sequence line impedance of all sections of a three-terminal line and the Thevenin equivalent impedance of the transmission network upstream from the monitoring location using protective relay data collected during short-Circuit Ground fault events. Protective relaying data from all three terminals may not be always available. Furthermore, the data from each terminal may be unsynchronized and collected at different sampling rates with dissimilar fault time instants. Hence, this paper presents approaches which use unsynchronized measurement data from all the terminals as well as data from only two terminals to estimate the zero-sequence line impedance of all the sections of a three-terminal line. An algorithm to calculate positive-, negative- and zero-sequence Thevenin impedance of the upstream transmission network has also been presented in this paper. The efficacy of the proposed algorithms are demonstrated using a test case. The magnitude error percentage in determining the zero-sequence impedance was less than 1% in the test case presented.
Da Hu - One of the best experts on this subject based on the ideXlab platform.
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automatic wire clamp for portable short Circuit Ground wire
2012Co-Authors: Zhihao Lu, Ming Fu, Yongbao Zhou, Dacheng Wang, Qin Yu, Da Hu, Jianbing Yang, Ye Cai, Wei Zhu, Feng XuAbstract:The invention discloses an automatic wire clamp for a portable short-Circuit Ground wire. The automatic wire clamp is easy and convenient to operate and wide in application range. The automatic wire clamp comprises an operating rod, a static bracket, a connecting shaft, a transmission rack, a pawl, a pawl spring and a movable wire clamp, wherein the transmission rack is connected to the front end of the connecting shaft; the pawl can be meshed with a tooth tip on the outer surface of the connecting shaft; the pawl spring is arranged between the static bracket and the pawl; and the movable wire clamp is connected to the static bracket. A fixed wire clamp is arranged on one side of the front part of the static bracket. An intermediate gear meshed with the transmission rack is also arranged in an inner cavity of the static bracket. The movable wire clamp comprises a middle opening part corresponding to the fixed wire clamp and a mounting part movably arranged on the static bracket. A rack meshed with the intermediate gear is arranged on the outer end face of the mounting part. The front end of the operating rod is connected with the connecting shaft through a limiting cam. A rib is arranged on the surface of an inner cavity on the rear part of the static bracket to stop the limiting cam continuing rotating when the high surface of the limiting cam rotates to the position of the rib. A resetting spring is connected between the fixed wire clamp and the movable wire clamp.