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The integration of distributed generation brings in new challenges for the operation of distribution networks, including out-of-limit voltage and power flow control. Soft open points (SOP) are new power electronic devices that can flexibly control active and reactive power flows. With the exception of active power output, photovoltaic (PV) devices can provide reactive power compensation through an inverter. Thus, a synergetic optimization operation method for SOP and PV in a distribution network is proposed. A synergetic optimization model was developed. The voltage deviation, network loss, and ratio of photovoltaic abandonment were selected as the objective functions. The PV model was improved by considering the three reactive power output modes of the PV inverter. Both the load fluctuation and loss of the SOP were considered. Three multi-objective optimization algorithms were used, and a compromise optimal solution was calculated. Case studies were conducted using an IEEE 33-node system. The simulation results indicated that the SOP and PVs complemented each other in terms of active power transmission and reactive power compensation. Synergetic optimization improves power control capability and flexibility, providing better power quality and PV consumption rate.

The series-type hybrid circuit breaker (S-HCB) is an effective solution for ultrafast dc fault protection. However, the introduction of multiple energy storage (ES) capacitors and fully controlled power devices for zero-current modulation leads to complex startup operations and significant-increased costs. In this article, a novel S-HCB with simple startup operation and low device cost for low-voltage dc distribution networks is proposed. The proposed design introduces an auxiliary coupled inductor into the voltage injection circuit to generate a multilevel injection voltage with only a single ES capacitor, which simplifies S-HCB's startup operation. Meanwhile, through comprehensively analyzing and designing the operating conditions for each device, some fully controlled power devices are replaced by low-cost SCRs and the required current ratings are reduced, obtaining significant device cost reduction without sacrificing performance. The operation principle and complete design consideration are detailed, and simulation and scaled-down experimental results are presented to verify the proposed concept. Compared to conventional S-HCB, the proposed design remains the inherent fast current breaking ability (300 V/30 A/14 $\mu$s) and efficient energy transmission (99.2%/6 kW) while simplifying the startup operation and achieving over 40% cost reduction in power devices.

Electro-aerodynamic unmanned aerial vehicles (EAD-UAVs) have strict requirements for lightweight. Due to the heavy weight of magnetic components and insulation materials, the power source of the EAD-UAV, an LCC high voltage power supply (HVPS)'s specific power cannot meet the minimum requirements. To improve the specific power of LCC HVPS, this article will optimize the magnetic core, insulation materials, and magnetic integrated transformer structure. First, the weight-frequency relation of the high-voltage transformer core is derived, and it is shown that there is an optimal frequency to minimize the weight of the high-voltage transformer core. Then, for insulation material optimization, the existing method points out that the input parallel output series (IPOS) array structure can reduce the amount of insulation material. This article uses the structure. But this article combined with the optimal frequency proposed the number of array transformers and insulation design method. Next, for each transformer in the array, an asymmetric magnetic integrated transformer structure is proposed. Which realizes the resonant inductance integration. At the same time, the magnetic shunt can be adjusted according to the needs of the winding. So, this structure can improve the utilization rate of the transformer window, and reduce the weight of the magnetic core. Finally, a 619 W-rated laboratory prototype is designed to convert 140 V input to 40 kV output. The designed IPOS transformer array weighs is 213.5 g, the total weight of the HVPS is 423.9 g, and the specific power is 1.46 kW/kg, working at the optimal frequency of 101.2 kHz.

3D non-equilibrium molecular dynamics simulations are performed to investigate the friction heat dissipation and generation of high-speed sliding system. A sliding simulation model with two blocks is built. The friction heat generation with different materials, different velocities are studied. The mechanism of the heat dissipation at the interface is investigated. The heat partition of different friction system is obtained. The results show that more friction heat will be produced with higher sliding velocity. But in the case with more plastic deformation, less friction heat will be generated. The heat partition is mainly influenced by the friction material and the velocity ratio. The material which has the similar thermodynamic properties will be easier to produce phonon with similar spectrum.

DC circuit breaker (DCCB) plays an important role in dc system protection as an execution unit for disconnecting fault lines. However, due to the nature of dc current, it is a challenge for DCCB to quickly turn off and isolate the fault current. Therefore, a new bidirectional DCCB with decision-making capability based on Z-source topology is proposed in this article, which is able to respond to a fault in a few microseconds. The proposed topology uses only one coupled inductor with a central tap structure in the core part, which improves the utilization ratio of the coupled inductor and reduces the volume and cost of the DCCB. Compared with previous DCCBs, the proposed topology has a simpler structure, fewer windings and components, and smaller volume. In this article, the turn off process of the proposed topology under the line fault condition is analyzed in detail, and the hardware circuit design process is given. The performance of the proposed topology was verified by MATLAB simulation and hardware experiments.

A large amount of transverse aeolian ridges (TARs) bedforms exist in the Zhurong rover landing region. The acquisition of high‐resolution data from the orbiter and the rover from Tianwen‐1 mission provides an excellent opportunity to study the geological characteristics of TARs. The length, width, and density of a total of 8,274 TAR samples at the landing site were analyzed. The orientation of TARs at the landing region is dominated in the E‐W direction. Analysis of Mars Climate Station (MCS) data on the Zhurong rover shows that the present‐day wind direction is inconsistent with the wind forces that promoted the formation of TARs, suggesting that the formation of TARs is dependent on the ancient wind direction. With the help of the Zhurong MarSCoDe shortwave infrared (SWIR) spectrometer data, we investigate the composition of materials including TARs, soil, and rocks, and the results show that their spectra display similar distinct absorptions consistent with the presence of hydrated minerals such as hydrated sulfates. The cemented and dusty crust covering the TARs indicates that the TARs have not migrated for a period of time in the landing site area. Some of the TARs have been eroded into small sand ridges or ripples due to the change in the prevailing wind directions, which may indicate the climate change on Mars. Using the high‐resolution remote sensing images from the orbiter and Zhurong rover of Tianwen‐1 mission, we identified a total of 8,274 aeolian bedforms at the landing site of the rover on the Utopia Planitia. These aeolian bedforms can be classified as transverse aeolian ridges (TARs) according to their morphology, size and other observational features. The detailed geometry such as the length, the width, the density, and orientation of these TARs were characterized and compared with Martian TARs measured in the previous studies. The TARs in the study area were found to have formed in an ancient wind regime. The TARs are covered with bright dust and their surfaces have been cemented. This suggests that these TARs have not moved for a long time. Some of the TARs have been eroded into small sand ripples. The cause of this may be related to the change in the direction of the ancient wind because the current wind direction derived from the Mars Climate Station (MCS) data on the Zhurong rover is found to be different from the ancient wind direction. The geomorphology of transverse aeolian ridges (TARs) at Zhurong landing area are mapped and analyzed and the results show that they formed at an ancient wind regimeThe cemented and dusty crust covering the TARs indicate that the TARs have not migrated for a period of timeSome of the TARs have been eroded due to the change of the prevailing wind directions which may indicate the climate change on Mars The geomorphology of transverse aeolian ridges (TARs) at Zhurong landing area are mapped and analyzed and the results show that they formed at an ancient wind regime The cemented and dusty crust covering the TARs indicate that the TARs have not migrated for a period of time Some of the TARs have been eroded due to the change of the prevailing wind directions which may indicate the climate change on Mars

Several tobamoviruses cause substantial economic losses to tomato and pepper crops globally, especially the pepper mild mosaic virus (PMMoV), tomato brown rugose fruit virus (ToBRFV), tomato mosaic virus (ToMV), and tomato mottle mosaic virus (ToMMV). A fast and accurate detection method is essential for virus identification. An all-in-one reaction method combining a one-step reverse-transcription recombinase-aided amplification (RT-RAA) and CRISPR/Cas12a-based lateral flow assay in one mixture was developed to rapidly screen and accurately differentiate among these four tobamoviruses for field detection in tomato and pepper plants. With a generic RT-RAA primer set and a mix of four specific crRNAs, along with a portable metal incubator and the use of a crude extraction method, this method screened for PMMoV, ToBRFV, ToMV, and ToMMV concurrently in less than 1 h, enabling field workers to take action immediately. The accurate differentiation of these four viruses could be achieved by later adding a single specific crRNA.

The electromagnetic radiation interference mechanism from multiple noise sources on the parallel topology of SiC MOSFET and Si IGBT Inverter is blurred, which will seriously affect the high reliability application of the structure. In order to solve this problem, a topological radiation EMI prediction method is proposed, the method includes the establishment of radiation equivalent models and radiation guidelines, the proposed inverter parallel topology radiation. The modeling method of electromagnetic interference can effectively analyze the influence of radiation interference of SiC and Si devices coupled with each other, and the established PCB radiation near and far field simulation can effectively realize the accurate prediction of radiation interference of inverter parallel topology, and finally the experimental platform of the parallel SiC MOSFET and Si IGBT inverter is built and tested, the test results demonstrate the accuracy of the proposed method.

Neotectonic movement refers to the tectonic movement that has happened since the Cenozoic, which is the latest movement. It has the most important influence on the basins in west China, especially on the hydrocarbon accumulation in the western foreland basins. We determined the time of neotectonic movement in the Kuqa Foreland Basin, which began from the Neogene, and analyzed the patterns of movement, which were continuous and fast subsidence in the vertical direction and intense lateral compression. The structure styles are that the faulting is weakened and the folding is strengthened gradually from north to south. We studied the control of neotectonic movement on the hydrocarbon accumulation process and model in the Kuqa Foreland Basin with basin simulation technique. The largest subsidence rate of the Kuqa Foreland Basin reached 1,200 m/Ma during the neotectonic movement, leading to rapid maturing of source rock within 5 Ma and a large quantity of hydrocarbon being generated and expelled. The thick neotectonic strata can form high quality reservoirs with the proved gas and oil reserves accounting for 5% and 27% of the total reserves, respectively. 86% of the structural traps were formed in the neotectonic movement period. The faults formed during the neotectonic movement serve as important migration pathways and they exist in the region where the hydrocarbon reservoirs are distributed. Abnormally high pressure caused by the intense lateral compression, thick neotectonic strata deposition and rapid hydrocarbon generation provide driving force for hydrocarbon migration. The accumulation elements match each other well over a short period, leading to many large gas fields formed later in the Kuqa Foreland Basin.

In this paper, two seal schemes of stepped labyrinth seal and straight through-hole seal are selected for the shaft end seal of S-CO2centrifugal compressor with the output of 100kW. The full three-dimensional CFD numerical simulation method is adopted to analyze and compare the sealing characteristics of two S-CO2seals in S-CO2centrifugal compressor under different outlet back pressures and sealing gaps. The results show that the leakage flow rate of S-CO2stepped labyrinth seal and through-hole seal increases with the decrease of back pressure. The leakage flow rate of the stepped labyrinth seal and the through-hole seal reaches the corresponding critical value when the back pressure is 1.0 MPa and 3.0 MPa respectively. The critical leakage flow rate of the stepped labyrinth seal and the through-hole seal under the condition of 0.1 mm sealing gap is 0.158 kg/s and 0.128 kg/s respectively. Compared to the through-hole seal, the stepped labyrinth seal can withstand greater pressure differentials at the same sealing gap and has superior S-CO2sealing performance.

Supercritical carbon dioxide Brayton cycle has significant advantages such as high efficiency, low cost and small size. Turbine is a key turbomachinery in the supercritical carbon dioxide Brayton cycle system. It works in the harsh environment of high pressure, high speed and high temperature gradient. The huge thermal stress is an important cause of the turbine structure failure. In this paper, the thermal stress analysis is conducted for a supercritical carbon dioxide turbine with an output of 200 kW and a rotational speed of 40,000 rpm. In order to consider the coupling relationship between the temperature field and the structural stress field, the flow-thermal-solid coupling analysis method is applied to calculate the thermal stress of the supercritical carbon dioxide turbine impeller. The results of thermal deformation and thermal stress analysis of the turbine impeller are obtained by the numerical simulation. The high stress region not only appears in the geometrical structure, but also in the region with large temperature gradient. The analysis results show that the maximum equivalent stress appears at the fillet between the turbine impeller and the seal with a value of 324 MPa. This value is less than the yield limit of the material at 500 degC. The turbine impeller structure meets the strength design requirements.