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Radially polarized intense terahertz (THz) radiation is measured experimentally behind a thin foil irradiated by ultrashort relativistic intense laser pulse of ultrahigh contrast. As the target thickness is reduced from 30 to 2 μm, the energy of the THz emission increases dramatically, which even reaches up to 10.5 mJ per pulse, corresponding to energy conversion efficiency of 1.7%. This efficient...
Based on the verified two dimensional(2D) finite element model for river flow simulation, the effect of estuary training levees on the water flow and sediment movement in the Yellow River estuary is analyzed. For disclosing the effect of setting the two training levees on the flow and sediment motion, the calculation and analysis for the two projects, (one is no levees, the other is setting up two...
Travelling wave fault location method has been used in power system, but its performance was affected by the frequency band limitation (<100kHz) of traditional current transformer (CT). As a new kind of transducer, Rogowski coil based electronic current transformer (R-ECT) has wide frequency bandwidth (several Hz to 1MHz) and differential output characteristic. Hilbert-Huang transform (HHT) is...
With the rapid development of power system, the traditional relay protection mode oriented to element cannot take on the heavy responsibilities for protection gradually. The paper constructs a hierarchical protection system of three layers distributed, which integrated the advantages of traditional protection, Substation Area Protection and Wide Area Protection. Firstly, the system's basic framework...
This paper proposes a VSC-MTDC transmission line protection scheme based on polarity comparison of superimposed current and resistive-type superconducting fault current limiter (R-SFCL). R-SFCLs utilize a current-driven transition from the superconducting state to the normal state to limit the short circuit current. Thus, DC circuit breakers can be used to break the fault current in the event of a...
This paper introduces the scheme for protection based on the needs of DG growth and automatic device control, which is to minimize fault duration, to prevent the DG damage by changing the substation grounding mode, configuration of protective device, the scheme for fixed value setting, automatic switch-on device and low-frequency low-voltage separation mode. Among them, the corresponding "Islands"...
Electrical explosion of single wire is the initial stage of wire array z-pinches. In order to study the physical process of single wire explosion, a small-scale pulsed power generator was established, which can provide positive and negative polarity current with the peak value of 3kA and the rise-time from 20ns to hundreds of nanoseconds. The single wire loads are bare and insulation coated tungsten...
Finite element modeling (FEM) was applied to investigate the reliability of solder joints in a chip scale package (CSP) device mounted to a printed circuit board (PCB). The stress/strain field distribution on solder joint interface zone as well as the failure mode of solder joints subjected to thermal cycling was analyzed. A unified viscoplastic constitutive model was used to describe the deformation...
For launch vehicles using the liquid hydrogen and liquid oxygen propulsion system, the autogenous pressurization and thrust augmentation system is common used to provide high pressure propellant flow. However, it is very difficult to precisely measure the flow rate of the pressurized high-speed gaseous oxygen flow. A flowmeter for the oxygen flowrate measurement in the autogenous pressurization system...
In this paper, the reliability and degradation mechanisms of high-brightness LEDs were studied, which were prepared by Cree and currently available on the market. Results revealed that operating currents had an important effect on the service performance of treated LEDs. Only at 350mA the tested LEDs had a good performance; at 750mA and 1000mA, they had the significant degradation; at 2000mA, they...
Recently the Chinese governments at all levels are in urgent need of both a manageable research project evaluation index system and a scientific evaluation method that could help them select those research projects which are valuable in promoting the country's economy and social development. In response to such a need, the present paper first suggests a useful research project evaluation index system...
AC electronic load (ACEL) based on current-controlled AC/DC/AC PWM converters is a simple kind of application for ac power source burn-in test with energy recycling capability. According to instantaneous power theory, the harmonics relationship in steady state between the ac side and the dc side of AC/DC converter and DC/AC converter in ACEL is investigated. When the frequency of the tested source...
The gate-all-around (GAA) silicon nanowire transistor (SNWT) is considered as one of the best candidates for ultimately scaled CMOS devices. This paper discusses the process impact on nanowire LER/LWR, as well as the impact of 2D nanowire LER on performance variation and degradation. And it is found that SNWTs, which is immune to channel RDF(random dopant fluctuation), exhibit SDE-RDF which is enhanced...
We describe a scalable nanocavity array, with single quantum dots, for universal single-operation N-qubit quantum gate. A single two-level system controls the lineshapes, departing from optical-analog of electromagnetically-induced-transparency, with high fidelity and low photon loss.
We describe a scalable nanocavity array, with single quantum dots, for universal single-operation N-qubit quantum gate. A single two-level system controls the lineshapes, departing from optical-analog of electromagnetically-induced-transparency, with high fidelity and low photon loss.
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