Residual flux density estimation of the three-phase transformer using BP neural network

When the off-line transformer is re-energized, the phase-controlled switching strategy can avoid the generation of inrush current by controlling the phase. To determine the closing phase, the residual flux density (Br) in the transformer core needs to be accurately measured. This paper proposes a Br estimation method for three-phase transformers based on the finite element method and BP neural network. Firstly, the direction of Br in each phase core is determined based on the transient current characteristics. Then, the three-phase transformer is simulated and the BP neural network is trained to estimate the Br based on the simulation results. The experimental results on a three-phase transformer show that the proposed method can accurately determine the direction and amplitude of Br in each phase of the three-phase transformer

Fast demagnetization method for power transformers combined with residual flux measurement

When power transformers are re-energized, the inrush current may be generated and damage electrical equipment. In order to suppress the generation of serious inrush current, the residual flux (RF) in the power transformer core needs to be eliminated. However, existing methods require first magnetizing the core to saturation to calibrate the magnetic flux due to the unknown residual flux density (Br), which increases demagnetization power and time. In addition, the lack of effective Br measurement methods makes it impossible to evaluate the demagnetization effect. Therefore, this paper proposes a demagnetization method that considers the amount of Br, which achieves accurate measurement and quantitative elimination of Br in the transformer core. The measurement is first performed by applying DC voltages of different polarities, and then a specific demagnetization DC voltage is applied based on the measurement results. The magnetic flux in the transformer core is reduced directly to zero without calibrating flux throughout the entire process. Experimental studies are performed on core-type transformers and 10 kV, 250 kVA power transformers, and the experiment results show that the Br is reduced to within 1 % of the knee-point flux and the measurement error is within 4 %, which proves the effectiveness of the proposed method. Compared with existing methods, the demagnetization time can be reduced to less than 1 s and the demagnetization power can be reduced by 95 % using the proposed method

Regulation of 2-acetyl-1-pyrroline and grain quality in early-season indica fragrant rice by nitrogen and silicon fertilization under different plantation methods

Fragrant rice has a high market value, and it is a popular rice type among consumers owing to its pleasant flavor. Plantation methods, nitrogen (N) fertilizers, and silicon (Si) fertilizers can affect the grain yield and fragrance of fragrant rice. However, the core commercial rice production attributes, namely the head rice yield (HRY) and 2-acetyl-1-pyrroline (2-AP) content of fragrant rice, under various nitrogen and silicon (N-Si) fertilization levels and different plantation methods remain unknown. The field experiment in this study was performed in the early seasons of 2018 and 2019 with two popular indica fragrant rice cultivars (Yuxiangyouzhan and Xiangyaxiangzhan). They were grown under six N-Si fertilization treatments (combinations of two levels of Si fertilizer, 0 kg Si ha−1 (Si0) and 150 kg Si ha−1 (Si1), and three levels of N fertilizer, 0 kg N ha−1 (N0), 150 kg N ha−1 (N1), and 220 kg N ha−1 (N2)) and three plantation methods (artificial transplanting (AT), mechanical transplanting (MT), and mechanical direct-seeding (MD)). The results showed that the N-Si fertilization treatments and all the plantation methods significantly affected the HRY and 2-AP content and related parameters of the two different fragrant rice cultivars. Compared with the Si0N0 treatment, the N-Si fertilization treatments resulted in higher HRY and 2-AP contents. The rates of brown rice, milled rice, head rice, and chalky rice of the fragrant rice also improved with the N-Si fertilization treatments. The N-Si fertilization treatments increased the activities of N metabolism enzymes and the accumulation of N and Si in various parts of the fragrant rice, and affected their antioxidant response parameters. The key parameters for the HRY and 2-AP content were assessed by redundancy analysis. Furthermore, the structural equation model revealed that the Si and N accumulation levels indirectly affected the HRY by affecting the N metabolism enzyme activity, N use efficiency, and grain quality of fragrant rice. Moreover, high N and Si accumulation directly promoted the 2-AP content or affected the antioxidant response parameters and indirectly regulated 2-AP synthesis. The interactions of the MT method with the N-Si fertilization treatments varied in the fragrant rice cultivars in terms of the HRY and 2-AP content, whereas the MD method was beneficial to the 2-AP content in both fragrant rice cultivars under the N-Si fertilization treatments

Hyper-tACS-induced interbrain synchronization in the frontal cortex improves romantic relationships

Interpersonal relationships are among the most essential yet fragile aspects of human life, and recent advances in dual-brain stimulation provide a unique opportunity to causally probe and modulate their neural underpinnings. While prior work has linked interpersonal brain synchronization (IBS) to relationship quality, its causal contribution to long-term relational outcomes remains unclear. Here, we present the first application of dual-brain transcranial alternating current stimulation (hyper-tACS) to social bonding, specifically targeting romantic partners, with a focus on the temporal dissociation between neural and behavioral effects. Across six consecutive days of intervention, active hyper-tACS induced clear increases in prefrontal IBS immediately after stimulation, yet these neural gains did not translate into concurrent improvements in subjective relationship satisfaction. Mediation analyses further showed that individual differences in IBS increases mediated the effect of baseline IBS on relationship improvement, suggesting that behavioral benefits rely on neural alignment consolidating over time. At a one-year follow-up, the active group exhibited a substantially lower breakup rate relative to sham controls. These findings provide causal evidence for a delayed effect of dual-brain stimulation, in which neural changes precede and gradually consolidate into durable relational benefits. Together, this work provides the first causal evidence that dual-brain stimulation can be extended from motor coordination to the social domain, advancing mechanistic accounts of intimacy and highlighting hyper-tACS as a translational tool for strengthening long-term relationship stability