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Encouraged by the goal of achieving net-zero carbon emission by 2050, the exploration of insulating material becomes one of the core projects to the electrical equipment innovations. The rise of composites enables the insulating material to be endowed with more functions. By this concern, adopting the coupling agents is one of the effective methods to improve the compatibility of composites, which highly strengthens the desired properties. The functional groups of coupling agents, nevertheless, could not always show a positive impact to access enhanced properties. In this work, four types of silane coupling agents including amino-propyl, glycidyletheroxy-propyl (GP), vinyl, and methacryloxy-propyl functional groups are employed to modify the aluminum nitride (AlN) fillers, and the modification effects on the insulating and thermal conductivity of the AlN/poly(m-phenylenedicarbonyl-m-phenylenediamine) (PMIA) composite paper are systematically investigated and compared. The results show that a proper coupling agent is beneficial to the uniform dispersion of the inorganic filler in the organic matrix and highly contributes to their interface quality, where the heat transfer path is established that boosts the heat dissipation. By tailoring the trap depth and density toward deeper and higher, the carrier transport is highly confined which enhances the breakdown strength to a large extent. Therefore, high breakdown strength and thermal conductivity of 182.9 kV mm−1 and 0.302 W (m·K)−1, respectively, are achieved in the GP modified AlN/PMIA paper, which are 16.7% and 167.4% higher than that of pure PMIA paper. [ABSTRACT FROM AUTHOR]

The plasma-beta effect on the n = 1 resonant magnetic perturbation (RMP) field penetration in purely radio-frequency (RF) wave heated discharges has been investigated in EAST. The experimental results show that the dependence of the threshold RMP coil current for field penetration, I RMP,th , on the total absorbed power P tot scales as approximately I RMP,th ∝ P tot 0.30 , indicating that the error-field tolerance is improved with increasing RF power. This is benefited by the increased electron perpendicular flow dominated by a counter-current electron diamagnetic flow with increasing RF power. However, theoretical scaling in cylindrical geometry overestimates the power index. Assuming an additional term β N α β N for the normalized beta in the scaling, it is shown that the fitted α β N from the experimental observation is around −1, indicating a degradation effect of plasma beta. To clarify the underlying physics of the plasma-beta effect that was not included in the theoretical scaling in cylindrical geometry, the MARS-Q code with full toroidal geometry is employed for simulation of nonlinear field penetration (Liu et al 2013 Phys. Plasmas 20 042503). The MARS-Q simulation results reproduce the β N dependence well, and hence the P tot scaling of the threshold current in experimental observations. The main reason for this is that the net total torque, which is mainly contributed by the neoclassical toroidal viscosity (NTV), increases with increasing plasma β N . The results demonstrate that the nonlinear toroidal coupling effect via NTV torque plays an important role in determining field penetration, even in cases with relatively low β N ∈ [ 0.3 , 0.6 ] , which is far less than the no-wall beta limit. [ABSTRACT FROM AUTHOR]

In order to improve the flashover voltage of the disc insulator in gas insulated transmission line under DC voltage, this paper considers reducing the electric field intensity on the surface by adjusting the surface conductivity distribution. Based on the joint simulation of improved particle swarm optimization algorithm and finite element, the surface conductivity gradient partition optimization model is constructed to obtain the optimal surface conductivity distribution sequence. The relationship between conductivity and treatment time is obtained by plasma fluorination, and the gradient distribution of the surface conductivity of the sample is realized by adding different ring polytetrafluoroethylene baffles. Microscopic tests are used to characterize the differences between different regions of the sample surface. The two-dimensional (2D) electric potential distribution, 2D charge density distribution, electric field intensity distribution and flashover voltage on the sample surface under pre-charging conditions are studied and compared with the simulation results. The results show that the maximum field strength of the sample with gradient treatment can be reduced by 71% and the flashover voltage can be increased by 45%. The research in this paper provides a good reference and theoretical support for the surface modification of disc insulators, such as the surface parameters with gradient distribution. [ABSTRACT FROM AUTHOR]

Atomic-force microscopic images, x-ray diffraction patterns, Urbach energies and photoluminescence quenching experiments show that the interfacial contact quality between the hydrophobic [6,6]-phenyl-C61-buttric acid methyl ester (PCBM) thin film and hydrophilic CH3NH3PbI3 (MAPbI3) thin film can be effectively improved by using a binary antisolvent mixture (toluene:dichloromethane or chlorobenzene:dichloromethane) in the anti-solvent mixture-mediated nucleation process, which increases the averaged power conversion efficiency of the resultant PEDOT:PSS (P3CT-Na) thin film based MAPbI3 solar cells from 13.18% (18.52%) to 13.80% (19.55%). Beside, the use of 10% dichloromethane (DCM) in the binary antisolvent mixture results in a nano-textured MAPbI3 thin film with multicrystalline micrometer-sized grains and thereby increasing the short-circuit current density and fill factor (FF) of the resultant solar cells. It is noted that a remarkable FF of 80.33% is achieved, which can be used to explain the stable photovoltaic performance without additional encapsulations. [ABSTRACT FROM AUTHOR]

The averaged power conversion efficiency of polyelectrolytes (P3CT-Na) based MAPbI3 solar cells can be increased from 14.94% to 17.46% with a wetting method before the spin-coating process of MAPbI3 precursor solutions. The effects of the wetting process on the surface, structural, optical and excitonic properties of MAPbI3 thin films are investigated by using the atomic-force microscopic images, x-ray diffraction patterns, transmittance spectra, photoluminescence spectra and Raman scattering spectra. The experimental results show that the wetting process of MAPbI3 precursor solution on top of the P3CT-Na/ITO/glass substrate can be used to manipulate the molecular packing structure of the P3CT-Na thin film, which determines the formation of MAPbI3 thin films. [ABSTRACT FROM AUTHOR]

Tl-based superconducting devices have been drawn much attention for their high transition temperature (Tc), which allow the high temperature superconductors (HTS) devices to operate at temperature near 100 K. The realization of Tl-based devices will promote the research and application of HTS devices. In this work, we present transport properties of Tl2Ba2CaCu2O8 (Tl-2212) microbridges across a low-angle step on LaAlO3 (LAO) substrate. We experimentally demonstrate intrinsic Josephson effects (IJEs) in Tl-2212 films by tailoring the geometry, i.e., reducing the width of the microbridges. In the case of a 1 μm width microbridge, in addition to the observation of voltage branches and remarkable hysteresis on the current–voltage (I–V) characteristics, the temperature dependence of differential resistance shows a finite resistance above 60 K when the bias current is below the critical current. For comparison, the wider microbridges are also investigated, exhibiting a highly critical current but do not showing obvious IJEs. [ABSTRACT FROM AUTHOR]

The corresponding description of this figure should be "As shown in Fig.2, the full width at half maximum (FWHM) of the Tl-1223(006) reflection peak is only 0.58 , which shows that the film possesses a good crystalline structure", instead of "As shown in Fig.2, the FWHM of the Tl-1223(003) reflection peak is only 0.58 , which shows that the film possesses a good crystalline structure". 36(2019)057401] Jian Xing( ) 1, Li-Tian Wang( ) 1, Xiao-Xin Gao( ) 1, Xue-Lian Liang( ) 1, Kai-Yong He( ) 1, Ting Xue( ) 1, Sheng-Hui Zhao( ) 1, Jin-Li Zhang( ) 1, Ming He( ) 1,2, Xin-Jie Zhao( ) 1,3, Shao-Lin Yan( ) 1, Pei Wang( ) 4, and Lu Ji( ) 1,3* 1 College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300350, China 2 Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology, Tianjin 300350, China 3 Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin, Tianjin 300350, China 4 Beijing Institute of Radio Measurement, Beijing 100854, China (Received 26 October 2020; accepted 18 December 2020; published online 27 January 2021) DOI: 10.1088/0256-307X/38/2/029901 1 4 1 6 1 8 2 0 0. 0 1. 5 3. 0 4. 5 6. 0 I n t e n s i t y (1 0 4 c p s) w (d e g) F W H M = 0. 5 8 O Fig. In Fig.2 of the article, [1] the figure caption should be"Rockingcurveofthe(006)peakoftheTl-1223thin film" instead of "Rocking curve of the (003) peak of the Tl-1223 thin film". [Extracted from the article]

Figure 2 in the original paper (Chin. Phys. B 27 057403 (2018)]) is replaced by a new one. [ABSTRACT FROM AUTHOR]

We report the circuit simulations and experiments of millimeter-wave radiation from a high temperature superconducting (HTS) bicrystal Josephson junction (BJJ) array. To study the effects of junction characteristic parameters on radiation properties, new radiation circuit models are proposed in this paper. The series resistively and capacitively shunted junction (RCSJ) models are packaged into a Josephson junction array (JJA) model in the simulation. The current-voltage characteristics (IVCs) curve and radiation peaks are simulated and analyzed by circuit models, which are also observed from the experiment at liquid nitrogen temperature. The experimental radiation linewidth and power are in good agreement with simulated results. The presented circuit models clearly demonstrate that the inconsistency of the JJA will cause a broad linewidth and a low detected power. The junction radiation properties are also investigated at the optimal situation by circuit simulation. The results further confirm that the consistent JJA characteristic parameters can successfully narrow the radiation linewidth and increase the power of junction radiation. [ABSTRACT FROM AUTHOR]

TlBa2Ca2Cu3O9 (Tl-1223) films have promising applications due to their high critical temperature and strong magnetic flux pinning. Nevertheless, the preparation of pure phase Tl-1223 film is still a challenge. We successfully fabricate Tl-1223 thin films on LaAlO3 (001) substrates using dc magnetic sputtering and a post annealing two-step method in argon atmosphere. The crystallization temperature of Tl-1223 films in argon is reduced by 100°C compared to that in oxygen. This greatly reduces the volatilization of Tl and improves the surface morphology of films. The lower annealing temperature can effectively improve the repeatability of the Tl-1223 film preparation. In addition, pure Tl-1223 phase can be obtained in a broad temperature zone, from 790°C to 830°C. In our study, the films show homogenous and dense surface morphology using the presented method. The best critical temperature of Tl-1223 films is characterized to be 110 K, and the critical current Jc (77 K, 0 T) is up to 2.13 × 106 A/cm2. [ABSTRACT FROM AUTHOR]

A graded fullerene derivative thin film was used as a dual-functional electron transport layer (ETL) in CH3NH3PbI3 (MAPbI3) solar cells, to improve the fill factor (FF) and device stability. The graded ETL was made by mixing phenyl-C61-butyric acid methyl ester (PCBM) molecules and C60-diphenylmethanofullerene-oligoether (C60-DPM-OE) molecules using the spin-coating method. The formation of the graded ETLs can be due to the phase separation between hydrophobic PCBM and hydrophilic C60-DPM-OE, which was confirmed by XPS depth-profile analysis and an electron energy-loss spectroscope. Comprehensive studies were carried out to explore the characteristics of the graded ETLs in MAPbI3 solar cells, including the surface properties, electronic energy levels, molecular packing properties and energy transfer dynamics. The elimination of the s-shape in the current density–voltage curves results in an increase in the FF, which originates from the smooth contact between the C60-DPM-OE and hydrophilic MAPbI3 and the formation of the more ordered ETL. There was an improvement in device stability mainly due to the decrease in the photothermal induced morphology change of the graded ETLs fabricated from two fullerene derivatives with distinct hydrophilicity. Consequently, such a graded ETL provides dual-functional capabilities for the realization of stable high-performance MAPbI3 solar cells. [ABSTRACT FROM AUTHOR]