The article designs a new type of bridge circuit with a controlled source—when the resistance on the bridge arm of the controlled source bridge circuit meets the bridge balance condition, and the bridge branch contai...The article designs a new type of bridge circuit with a controlled source—when the resistance on the bridge arm of the controlled source bridge circuit meets the bridge balance condition, and the bridge branch contains only one Current-Controlled Current Source (CCCS), a Voltage-Controlled Current Source (VCCS), a Current-Controlled Voltage Source (CCVS), or a Voltage-Controlled Voltage Source (VCVS), the circuit is called a controlled bridge circuit, which has the characteristics of bridge balance. Due to the relationship between the controlled source and the bridge arm, the sensitivity of the components on the bridge is higher mathematically and logically. When applied to measurement, engineering, automatic control, and other fields, the controlled bridge circuit has higher control ac-curacy. Mathematical derivation and simulation results prove the correctness of the bridge balance conclusion and the special properties of this bridge when applied to the measurement field.展开更多
We discuss a scheme for probabilistic and controlled teleportation of an unknown arbitrary three-particle state by constructing a peculiar non-maximally entangled state as a controlled quantum channel, which is telepo...We discuss a scheme for probabilistic and controlled teleportation of an unknown arbitrary three-particle state by constructing a peculiar non-maximally entangled state as a controlled quantum channel, which is teleported between two sides with the help of the auxiliary particle and the cooperation of the third side （Charlie） as a supervisor. In comparison with some existing schemes, on the receiver＇s side it is easy to have the sender＇s state through operating two uniform unitary transformations in turn. In addition, we also give an efficient quantum network for implementing the new scheme by means of some primitive operations.展开更多
A ZW-126/D2000-40 type single-break vacuum circuit breaker(VCB)with controlled switching technology is designed and produced in this paper.The results of type tests based on IEC and GB standards are presented.A 126 kV...A ZW-126/D2000-40 type single-break vacuum circuit breaker(VCB)with controlled switching technology is designed and produced in this paper.The results of type tests based on IEC and GB standards are presented.A 126 kV singlebreak vacuum interrupter(VI)with 3/4 coil axial magnetic field(AMF)contacts is used in the VCB,which can interrupt short currents of 40 kA.The external insulation of the VI is provided by SF_(6) at 0.1 MPa.In order to match the 126 kV single-break VI and controlled switching device,a long-stroke electro-magnetic force actuator(EMFA)with 16 kN closing holding force and 3.5 m/s average opening speed is designed.Moreover,a position tracking controlled switching device based on closed-loop control using the technology of a fuzzy control algorithm and pulse width modulation is applied to the controlled switching device.This device is applied to control the coil current of EMFA and the electromagnetic force,so as to control the EMFA to follow the ideal position curve.The type tests of 126 kV VCB are all passed according to the IEC62271-100 and GB1984-2014,including dielectric tests,basic short-circuit tests,shortline fault tests,out-of-phase tests,etc.The strong capacitive current breaking capacity and mechanical strength of the VCB are proved by the capacitive current switching test of class C2,electrical endurance test of class E2 and mechanical endurance test of class M2.The electromagnetic compatibility(EMC)tests are passed according to the IEC61000-4.The controlled switching test of capacitive current was successful according to IEC62271-302 and GB/T30846-2014,and the controlled switching accuracy is less than±0.5 ms.The test results show that the VCB has excellent performance,which has broad application prospects in special occasions at a 126 kV voltage level,such as a switching capacitor and no-load transformer,etc.展开更多
We propose an efficient scheme to implement a multiplex-controlled phase gate with multiple photonic qubits simultaneously controlling one target photonic qubit based on circuit quantum electrodynamics(QED).For conven...We propose an efficient scheme to implement a multiplex-controlled phase gate with multiple photonic qubits simultaneously controlling one target photonic qubit based on circuit quantum electrodynamics(QED).For convenience,we denote this multiqubit gate as MCP gate.The gate is realized by using a two-level coupler to couple multiple cavities.The coupler here is a superconducting qubit.This scheme is simple because the gate implementation requires only one step of operation.In addition,this scheme is quite general because the two logic states of each photonic qubit can be encoded with a vacuum state and an arbitrary non-vacuum state|φ>(e.g.,a Fock state,a superposition of Fock states,a cat state,or a coherent state,etc.)which is orthogonal or quasi-orthogonal to the vacuum state.The scheme has some additional advantages:because only two levels of the coupler are used,i.e.,no auxiliary levels are utilized,decoherence from higher energy levels of the coupler is avoided;the gate operation time does not depend on the number of qubits;and the gate is implemented deterministically because no measurement is applied.As an example,we numerically analyze the circuit-QED based experimental feasibility of implementing a three-qubit MCP gate with photonic qubits each encoded via a vacuum state and a cat state.The scheme can be applied to accomplish the same task in a wide range of physical system,which consists of multiple microwave or optical cavities coupled to a two-level coupler such as a natural or artificial atom.展开更多
Even though switching in vacuum is a technology with almost 100 years of history,its recent develop-ments are still changing the future of power transmission and distribution systems.First,current switch-ing in vacuum...Even though switching in vacuum is a technology with almost 100 years of history,its recent develop-ments are still changing the future of power transmission and distribution systems.First,current switch-ing in vacuum is an eco-friendly technology compared to switching in SF 6 gas,which is the strongest greenhouse gas according to the Kyoto Protocol.Vacuum,an eco-friendly natural medium,is promising for reducing the usage of SF 6 gas in current switching in transmission voltage.Second,switching in vacuum achieves faster current interruption than existing alternating current(AC)switching technolo-gies.A vacuum circuit breaker(VCB)that uses an electromagnetic repulsion actuator is able to achieve a theoretical limit of AC interruption,which can interrupt a short-circuit current in the first half-cycle of a fault current,compared to the more common three cycles for existing current switching technologies.This can thus greatly enhance the transient stability of power networks in the presence of short-circuit faults,especially for ultra-and extra-high-voltage power transmission lines.Third,based on fast vacuum switching technology,various brilliant applications emerge,which are benefiting the power systems.They include the applications in the fields of direct current(DC)circuit breakers(CBs),fault current lim-iting,power quality improvement,generator CBs,and so forth.Fast vacuum switching technology is promising for controlled switching technology in power systems because it has low variation in terms of opening and closing times.With this controlled switching,vacuum switching technology may change the“gene”of power systems,by which power switching transients will become smoother.展开更多
文摘The article designs a new type of bridge circuit with a controlled source—when the resistance on the bridge arm of the controlled source bridge circuit meets the bridge balance condition, and the bridge branch contains only one Current-Controlled Current Source (CCCS), a Voltage-Controlled Current Source (VCCS), a Current-Controlled Voltage Source (CCVS), or a Voltage-Controlled Voltage Source (VCVS), the circuit is called a controlled bridge circuit, which has the characteristics of bridge balance. Due to the relationship between the controlled source and the bridge arm, the sensitivity of the components on the bridge is higher mathematically and logically. When applied to measurement, engineering, automatic control, and other fields, the controlled bridge circuit has higher control ac-curacy. Mathematical derivation and simulation results prove the correctness of the bridge balance conclusion and the special properties of this bridge when applied to the measurement field.
文摘We discuss a scheme for probabilistic and controlled teleportation of an unknown arbitrary three-particle state by constructing a peculiar non-maximally entangled state as a controlled quantum channel, which is teleported between two sides with the help of the auxiliary particle and the cooperation of the third side （Charlie） as a supervisor. In comparison with some existing schemes, on the receiver＇s side it is easy to have the sender＇s state through operating two uniform unitary transformations in turn. In addition, we also give an efficient quantum network for implementing the new scheme by means of some primitive operations.
基金This work is supported by the National Natural Science Foundation of China(No.51877026 and No.51337001)the Science&Technology Project of SGCC(No.5229CG15003Q).
文摘A ZW-126/D2000-40 type single-break vacuum circuit breaker(VCB)with controlled switching technology is designed and produced in this paper.The results of type tests based on IEC and GB standards are presented.A 126 kV singlebreak vacuum interrupter(VI)with 3/4 coil axial magnetic field(AMF)contacts is used in the VCB,which can interrupt short currents of 40 kA.The external insulation of the VI is provided by SF_(6) at 0.1 MPa.In order to match the 126 kV single-break VI and controlled switching device,a long-stroke electro-magnetic force actuator(EMFA)with 16 kN closing holding force and 3.5 m/s average opening speed is designed.Moreover,a position tracking controlled switching device based on closed-loop control using the technology of a fuzzy control algorithm and pulse width modulation is applied to the controlled switching device.This device is applied to control the coil current of EMFA and the electromagnetic force,so as to control the EMFA to follow the ideal position curve.The type tests of 126 kV VCB are all passed according to the IEC62271-100 and GB1984-2014,including dielectric tests,basic short-circuit tests,shortline fault tests,out-of-phase tests,etc.The strong capacitive current breaking capacity and mechanical strength of the VCB are proved by the capacitive current switching test of class C2,electrical endurance test of class E2 and mechanical endurance test of class M2.The electromagnetic compatibility(EMC)tests are passed according to the IEC61000-4.The controlled switching test of capacitive current was successful according to IEC62271-302 and GB/T30846-2014,and the controlled switching accuracy is less than±0.5 ms.The test results show that the VCB has excellent performance,which has broad application prospects in special occasions at a 126 kV voltage level,such as a switching capacitor and no-load transformer,etc.
基金This work was partly supported by the National Natural Science Foundation of China(NSFC)(Nos.11074062,11374083,11774076,U21A20436)the Key-Area Research and Development Program of GuangDong Province(No.2018B030326001)the Jiangxi Natural Science Foundation(No.20192ACBL20051).
文摘We propose an efficient scheme to implement a multiplex-controlled phase gate with multiple photonic qubits simultaneously controlling one target photonic qubit based on circuit quantum electrodynamics(QED).For convenience,we denote this multiqubit gate as MCP gate.The gate is realized by using a two-level coupler to couple multiple cavities.The coupler here is a superconducting qubit.This scheme is simple because the gate implementation requires only one step of operation.In addition,this scheme is quite general because the two logic states of each photonic qubit can be encoded with a vacuum state and an arbitrary non-vacuum state|φ>(e.g.,a Fock state,a superposition of Fock states,a cat state,or a coherent state,etc.)which is orthogonal or quasi-orthogonal to the vacuum state.The scheme has some additional advantages:because only two levels of the coupler are used,i.e.,no auxiliary levels are utilized,decoherence from higher energy levels of the coupler is avoided;the gate operation time does not depend on the number of qubits;and the gate is implemented deterministically because no measurement is applied.As an example,we numerically analyze the circuit-QED based experimental feasibility of implementing a three-qubit MCP gate with photonic qubits each encoded via a vacuum state and a cat state.The scheme can be applied to accomplish the same task in a wide range of physical system,which consists of multiple microwave or optical cavities coupled to a two-level coupler such as a natural or artificial atom.
基金supported in part by the National Natural Science Foundation of China (51937009 and 51877166)the Key Research and Development Program of Shaanxi Province (2019ZDLGY18-04)
文摘Even though switching in vacuum is a technology with almost 100 years of history,its recent develop-ments are still changing the future of power transmission and distribution systems.First,current switch-ing in vacuum is an eco-friendly technology compared to switching in SF 6 gas,which is the strongest greenhouse gas according to the Kyoto Protocol.Vacuum,an eco-friendly natural medium,is promising for reducing the usage of SF 6 gas in current switching in transmission voltage.Second,switching in vacuum achieves faster current interruption than existing alternating current(AC)switching technolo-gies.A vacuum circuit breaker(VCB)that uses an electromagnetic repulsion actuator is able to achieve a theoretical limit of AC interruption,which can interrupt a short-circuit current in the first half-cycle of a fault current,compared to the more common three cycles for existing current switching technologies.This can thus greatly enhance the transient stability of power networks in the presence of short-circuit faults,especially for ultra-and extra-high-voltage power transmission lines.Third,based on fast vacuum switching technology,various brilliant applications emerge,which are benefiting the power systems.They include the applications in the fields of direct current(DC)circuit breakers(CBs),fault current lim-iting,power quality improvement,generator CBs,and so forth.Fast vacuum switching technology is promising for controlled switching technology in power systems because it has low variation in terms of opening and closing times.With this controlled switching,vacuum switching technology may change the“gene”of power systems,by which power switching transients will become smoother.
