关键词：
C -V characteristic;Interface traps;Short circuit (SC);Silicon carbide (SiC) MOSFET;Shunting of current
摘要：
The high trap density at the SiC/SiO2 interface is still the major reliability issue of silicon carbide (SiC) metal-oxide-semiconductor field effect transistors (MOSFETs). In this paper, we analyse the influence of the channel region and JFET region on the C-V curve from the band perspective. We proposed an approach to extract the oxide interface characteristics of a SiC MOSFET by fitting the measured C-V characteristic curve with the TCAD simulated curve. Then, the extracted SiC/SiO2 interface characteristics were verified by fitting the measured and simulated I-V curves and threshold voltages (VTH) at different lattice temperatures. Next, the extracted interface characteristics and the fixed interface charge were separately added to the TCAD model for comparison of the short-circuit simulations. It was found that the former model failed earlier than the latter and that the peak short-circuit current value was lower. The causes of these two phenomena are attributed to the different leakage degrees of the hole current in the Pbase region below the channel caused by interface traps and the difference in the channel mobility, respectively. Last, according to current shunt theory, P-type blocks were added below the JFET area to reduce the current during a short-circuit transient, thus improving the capacity to withstand a short circuit by approximately 22.4%.
摘要：
Layered double hydroxide (LDH) has been regarded as one of ideal electrode for supercapacitors due to layered structure, multiple redox active centers, and synergistic effects between metal ions. However, low capacitance and poor cycling stability greatly limit their large-scale application. Herein, nickel-aluminum layered double hydroxide (NiAl-LDH) onto nickel foam has been prepared by a simple one-step hydrothermal method, with the charge storage capability controlled by using different reactant concentration. It is found that the reactant concentration can regulate the morphology, crystallinity and loading density of NiAl-LDH. The optimized NiAl-LDH (Ni1Al1-LDH) shows a porous nanosheet structure with oxygen defects, which tightly covers on the nickel foam to facilitate ion and electron transfers, improving the redox activity of Ni ions and thus energy storage. As a supercapacitor electrode, the Ni1Al1-LDH achieves a specific capacitance of 1958.1 F/g at a current density of 1 A/g. The capacitance retention rate can reach as high as 108.7% up to 1000 cycles of continuous charge and discharge at a scan rate of 100 mV/s.
通讯机构：
[Zong, QG ] P;[Zhang, XX ] C;Peking Univ, Sch Earth & Space Sci, Beijing 100871, Peoples R China.;China Meteorol Adm, Natl Satellite Meteorol Ctr, Natl Ctr Space Weather, Key Lab Space Weather, Beijing 100081, Peoples R China.;Innovat Ctr Feng Yun Meteorol Satellite FYSIC, Beijing 100081, Peoples R China.
关键词：
AC vector magnetometer;low-resource magneto-impedance sensor;FY-3E satellite
摘要：
This study proposes a novel AC vector magnetometer developed using a low-resource magneto-impedance sensor for China's Feng-Yun meteorological satellite (FY-3E). It was calibrated and characterized to determine its performance parameters. The total weight of the AC vector magnetometer is 51 g (the aluminum box excluded), while the total power consumption is 310 mW. The proposed AC vector magnetometer can detect magnetic field variations in the range of +/- 1000 nT and noise power spectral density of <= 50 pT/Hz(1/2) @ 1 Hz. Furthermore, the proposed device has a maximum nonlinearity of <= 0.71 parts per thousand over the entire range and a nonorthogonality error of 3.07 nT or 0.15% (root mean square). The total dose hardness of the sensor is >= 30 krad (Si). Furthermore, we propose the first survey results of a magnetometer equipped aboard a Chinese FY-3E satellite in a Sun-synchronous orbit. The data revealed that the AC vector magnetometer can detect transient physical signals such as quasistatic field-aligned currents (similar to 50 nT) and waves at the auroral latitudes. These features render the proposed AC vector magnetometer suitable for space-based applications, particularly those involving the study of geomagnetic activity.
摘要：
Transmission lines are often located in complex environments and are susceptible to the presence of foreign objects. Failure to promptly address these objects can result in accidents, including short circuits and fires. Existing foreign object detection networks face several challenges, such as high levels of memory consumption, slow detection speeds, and susceptibility to background interference. To address these issues, this paper proposes a lightweight detection network based on deep learning, namely YOLOv5 with an improved version of CSPDarknet and a Swin Transformer (YOLOv5-IC-ST). YOLOv5-IC-ST was developed by incorporating the Swin Transformer into YOLOv5, thereby reducing the impact of background information on the model. Furthermore, the improved CSPDarknet (IC) enhances the model's feature-extraction capability while reducing the number of parameters. To evaluate the model's performance, a dataset specific to foreign objects on transmission lines was constructed. The experimental results demonstrate that compared to other single-stage networks such as YOLOv4, YOLOv5, and YOLOv7, YOLOv5-IC-ST achieves superior detection results, with a mean average precision (mAP) of 98.4%, a detection speed of 92.8 frames per second (FPS), and a compact model size of 10.3 MB. These findings highlight that the proposed network is well suited for deployment on embedded devices such as UAVs.
作者机构：
School of Physics and Electronics, Hunan University, Changsha 410082, China;Hunan Pin Teng Technology Co., Ltd., Changsha 410006, China;[Wang, Yaodong; Zou, Wanghui] School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 410114, China;Author to whom correspondence should be addressed.;[Gu, Hongbo] School of Physics and Electronics, Hunan University, Changsha 410082, China<&wdkj&>Hunan Pin Teng Technology Co., Ltd., Changsha 410006, China
通讯机构：
[Junlong Tang] S;School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 410114, China<&wdkj&>Author to whom correspondence should be addressed.
关键词：
voltage comparator;self-calibration;offset voltage cancellation;successive approximation register analog-to-digital converter (SAR ADC)
摘要：
A novel self-calibration comparator for a 12-bit 2.5 MSPS successive approximation register analog-to-digital converter (SAR ADC) applied in a touch microcontroller unit (MCU) with small area, high precision, fast response speed, and low-voltage detection is proposed in this paper. A combination of input/output offset storage (IOS/OOS) and an offset trimming circuit was employed to reduce the offset of the cascade preamplifier and the operational transconductance amplifier (OTA), a novel offset trimming circuit with a 5-bit digital controller was designed to further reduce the residual offset voltage, and an improved self-calibration technology was also implemented to compensate the conversion error in SAR ADC system to a minimum. Simulation and measured results show that the input-referred offset calibrating range is ±9.15 mV at 0.61 mV/step, the low-voltage detection of SAR ADC is realized by compensating the conversion error to a minimum, and the effective number of bits (ENOB) and figure of merit (FoM) at 5 V supply and 2.5 M/s rate in the 12-bit SAR ADC with a 95 nm CMOS are 11.33 bits and 726.6 fJ/conversion-step, respectively. The proposed self-calibration comparator applied in the SAR ADC system can automatically eliminate the offset voltage caused by nonidealities and meet the requirements of the touch MCU.
关键词：
First principle;Ferroelectric;VdW heterostructure;Valleytronics
摘要：
Two-dimensional (2D) ferroelectric materials have intrinsic polarized electric field, when they stack with other 2D materials to construct ferroelectric van der Waals heterostructures, they will produce a lot of novel properties, which has aroused extensive research interests. Therefore, based on first-principle calculations, we have comprehensively studied the electronic properties of LaBr2/& alpha;-In2Se3 ferroelectric heterostructures to investigate the reversibility and nonvolatility with information. Our calculations show that, the system is a ferromagnetic semiconductor with intrinsic valley polarization when & alpha;-In2Se3 is in the ferroelectric polarized up state. By switching the ferroelectric polarization of & alpha;-In2Se3, the heterostructure undergoes a transition from semi-conductor to half metal, which can be attributed to the competition between the built-in electric field (Eint) and ̅& RARR; the polarized electric field Epi ,generated by the charge transfer at interface of heterostructure and the bound charge of & alpha;-In2Se3, respectively. Besides, the band arrangement types of LaBr2/& alpha;-In2Se3 heterostructure can be well modulated under extra electric filed and biaxial strain. Furthermore, we have observed valley-submerging under electric filed and strain, which indicates the valleytronic nature can also be on-off in LaBr2/& alpha;-In2Se3 heterostructures. More importantly, the realization of reversible and non-volatile properties depends on the intrinsic characteristics of heterostructure and does not require external mechanisms. Our research not only provides the possibility for the application of the LaBr2/& alpha;-In2Se3 heterostructures in nanodevices, but also give the theoretical support to the study of spintronics and valleytronics.
摘要：
This paper presents an anti-swing control method to prevent situations where inspection robots detach and fall off transmission lines during obstacle crossing due to excessive swing angles caused by the rotation of the robot around the transmission line. Firstly, an obstacle-crossing model for the inspection robot was constructed and the causes of robot swinging phenomena were analyzed, in addition to their impact on obstacle crossing stability. By combining this with the obstacle-crossing model, a moment balance equation was established for the inspection robot. This equation can be used to solve mapping relationships between body offset and the tilt angle of transmission line gripping arms. We propose an anti-swing control strategy by adjusting the angle of the transmission line gripping arm’s pitching joint to make the body offset approach zero, and by utilizing the advantages of fuzzy logic in the fuzzy PID algorithm compared with the traditional PID algorithm, it can adaptively avoid the occurrence of robot swinging phenomena. The experimental results of obstacle-crossing experiments under no wind and wind turbulence conditions indicated that the proposed anti-swing control method in this study can effectively keep the body offset to within 3 mm. Compared with the methods of not using anti-swing control and using traditional PID anti-swing control, in the absence of wind effects, the peak values of body offset were reduced by 96.53% and 18.85%, respectively. Under the influence of wind turbulence, the peak values of body offset were reduced by 97.02% and 27.12%, respectively. The effectiveness of the anti-swing control method proposed in this paper has thus been verified.
摘要：
We explore the deuteron under strong magnetic fields in Skyrme models. The effects of the derivative dependent sextic term in the Skyrme Lagrangian are investigated, and the rational map approximation is used to describe the deuteron. The influences of strong magnetic fields on the electric charge distribution and mass of the deuteron are discussed.
通讯机构：
[Lijuan Wu] H;Hunan Provincial Key Laboratory of Flexible Electronic Materials Genome Engineering, The School of Physics & Electronic Science, Changsha University of Science & Technology, Changsha, 410114, China
关键词：
High-k;Back gate;Breakdownvoltage;Polarization charge;Specific on-resistance;Analytical model
摘要：
The analytical model of high -k SOI pLDMOS (HK SOI pLDMOS) with adaptive polarization charges is proposed in this paper. The HK SOI pLDMOS structure features a HK dielectric trench, which can introduce polarization charges to keep inner self-charge balance with the ions in the drift region and the carriers in the substrate. The HK trench assists the depletion in drift region to decreased the special on-resistance (RON,sp). In order to further modulate the electric field and reduce the RON,sp, a back gate is planted in the substrate. The analytical model of potential and the surface electric field distribution with in the HK trench is obtained by solving the Poisson equation. According to that a design formula is further deduced where the impact of high -k dielectric and back gate voltage are involved. The simulation results show that the proposed structure exhibits a breakdown voltage (VB) of-298 V and an RON,sp of 10.28 m omega cm2, at a back gate bias of-100 V. Compared with the conventional (Con.) trench SOI pLDMOS, RON,sp is decreased by 23.17%, and the VB is improved by 15.94%.
通讯机构：
[Si Liu] S;School of Physics and Electronic Sciences, Changsha University of Science and Technology , Changsha 410114, China
摘要：
Electron cyclotron harmonic (ECH) waves, contributing significantly to magnetospheric dynamics, usually appear as a series of harmonics between the multiples of electron gyrofrequency. Previous studies have demonstrated that ECH waves are the electron Bernstein mode excited by the electron loss cone distribution. To investigate how the electron distribution controls the frequency and wave normal angle of excited ECH waves, we derive a concise analytic formula for ECH growth rates using the bi-Maxwellian distribution. Parametric studies show that the expansion of the loss cone size could effectively enlarge ECH growth rates and move the peak growth rates to a smaller wave number k (higher frequency) region, while the deepening of the loss cone can only increase the growth rates. It is also found that the growth rate pattern in the k space exhibits different trends on the two sides of 1.5 fce because the dominant resonance orders on the two sides are different. This study further develops our understanding of the generation mechanism of ECH waves.
关键词：
Limiting;Circuit faults;Fault currents;Topology;Mathematical models;Superconducting films;Iron;Multiterminal DC (MTDC) distribution system;current limiting performance;superconductor fault current limiter (SFCL);dc circuit breaker (DCCB);interrupting performance
摘要：
Multiterminal DC (MTDC) distribution systems have a sharply rising speed and high fault current. Superconductor fault current limiter (SFCL) can effectively mitigate this issue. While several topologies of SFCLs have been proposed, no comparative analysis of their current limiting performance in combination with dc circuit breakers (DCCBs) in MTDC distribution systems has been conducted. In this article, three types of SFCLs are modeled, including the resistive SFCL (R-SFCL), saturated iron core SFCL, and hybrid SFCL for a four-terminal +/- 10 kV dc distribution system, and the fault current is computed. In addition, the application of three types of SFCLs on H-DCCB is studied, and the factors that affect the current limiting performance of SFCLs are discussed. Furthermore, a comparative analysis of the interrupting performance of H-DCCB combined with different types of SFCL is investigated. The results show that when the operating speed of H-DCCB is quick, the R-SFCL is the most suitable for limiting the fault current in MTDC distribution system.
摘要：
Magnetosonic (MS) wave is one of the most common electromagnetic emissions in the magnetosphere, while quasi-electrostatic magnetosonic (QEMS) waves are seldom observed. Here we present an interesting QEMS event detected by Van Allen Probe A on 9 January 2014, in which the presence of multi-band QEMS emissions shows evident correlations with relatively low plasma densities (∼10 cm−3) and enhancements of suprathermal (∼10 − 100 eV) proton fluxes. Based on the observed proton distributions, simulations demonstrate very similar profiles to the observed QEMS in the wave spectral characteristics. Parametric studies indicate that the QEMS growth rate can increase by ∼20 times with the plasma density decreasing from 50 to 10 cm−3. Effective growth rates of higher-band QEMS occur when the suprathermal proton population is sufficiently large. This study reveals that low densities and large suprathermal proton populations are favorable for generating distinct multi-band QEMS in the magnetosphere.
Multi-band quasi-electrostatic magnetosonic (QEMS) was observed exactly corresponding to low plasma densities and enhanced suprathermal proton fluxes
Simulations indicate that QEMS growth rate can increase by about 20 times with the plasma density decreasing from 50 to 10 cm−3
A large suprathermal (∼10–100 eV) proton population is favorable for extending the QEMS to higher bands
Magnetosonic (MS) wave is one of the most common electromagnetic emissions in the magnetosphere, while quasi-electrostatic magnetosonic (QEMS) wave is seldom observed. Here we report an interesting event detected by Van Allen Probe A on 9 January 2014, in which multi-band QEMS emissions occurred exactly corresponding to the presence of low plasma densities (∼10 cm−3) and enhancements of suprathermal (∼10 − 100 eV) proton fluxes. Based on the observed data of three typical time intervals, we perform simulations to investigate how the plasma density and suprathermal protons affect the generation of QEMS. Our results are quite comparable with the observations in the patterns of wave intensity and frequency characteristics. We then adjust the parameters and find that QEMS growth rate increases by ∼20 times with the plasma density decreasing from 50 to 10 cm−3. Effective growth rates of higher-band QEMS only occur when the suprathermal proton population is ≥0.75 cm−3. These results demonstrate that the low plasma density is propitious for generating distinct QEMS, and a sufficiently large suprathermal proton population is beneficial for forming the multi-band structure of QEMS.
摘要：
The electronic properties of CrI3/SnC heterostructure are investigated by the first-principles method. The Curie temperature (Tc) of CrI3/SnC heterostructure (57.1 K) is higher than that of monolayer CrI3 (similar to 45 K) significantly, and the nonmagnetic SnC monolayer is also magnetized. CrI3/SnC heterostructure shows an intrinsic type-II band alignment with the band gap (Eg) of 0.34 eV, which facilitates the separation of photogenerated electrons and holes in photoelectric devices. Applying strain and electric field (Eext) can effectively tune the electronic properties of the heterostructure. The transition from semiconductor to metal can be observed when applying greater horizontal strain or stronger Eext. The highest Tc can reach 89.4 K and 207.2 K by applying vertical compressive strain and horizontal uniaxial compressive strain, respectively. The half-metal feature can be realized when E-ext = -0.8 V/nm. These findings suggest a new possibility for developing magnetic heterostructure devices.
