Thermally conductive materials (TCMs) are highly desirable for thermal management applications to tackle the “overheating” concerns in the electronics industry. Despite recent progress, the development of high performance TCMs integrated with an in-plane thermal conductivity (TC) higher than 50.0 W (m K)⁻¹ and a through-plane TC greater than 10.0 W (m K)⁻¹ is still challenging. Herein, self-standing liquid metal@boron nitride (LM@BN) bulks with ultrahigh in-plane TC and through-plane TC were reported for the first time. In the LM@BN bulks, LM could serve as a bonding and thermal linker among the oriented BN platelets, thus remarkably accelerating heat transfer across the whole system. Benefiting from the formation of a unique structure, the LM@BN bulk achieved an ultrahigh in-plane TC of 82.2 W (m K)⁻¹ and a through-plane TC of 20.6 W (m K)⁻¹, which were among the highest values ever reported for TCMs. Furthermore, the LM@BN bulks exhibited superior compressive and leakage-free performances, with a high compressive strength (5.2 MPa) and without any LM leakage even after being crushed. It was also demonstrated that the excellent TCs of the LM@BN bulks made them effectively cool high-power light emitting diode modules. This work opens up one promising pathway for the development of high-performance TCMs for thermal management in the electronics industry.

Performance evaluations of a MW-class dynamic voltage restorer (DVR) system are presented for mitigation of voltage quality disturbances. A presag compensation strategy is introduced to lock the instantaneous magnitudes and phase angles of real-time line voltages, and thus to compensate the improper voltage components exactly after symmetrical or asymmetrical voltage disturbances. A 0.3-H/1.76-kA superconducting magnetic energy storage (SMES) magnet is used to cooperate with conventional battery energy storage (BES) device for developing a high-performance hybrid energy storage (HES) system. In the SMES-BES HES-based DVR system, the SMES can compensate the worst voltage sag for five cycles (1 MW, 100 ms, and absorb the highest voltage swell for six cycles (1 MW, 120 ms). The accessorial high-capacity BES device is subsequently discharged or charged for lasting long-time mitigation operations. Various simulation cases with regard to combined voltage sag, swell, and harmonic disturbances are carried out. The simulations and comparisons among the SMES-based, BES-based, and HES-based DVR schemes have demonstrated that the HES-based DVR scheme integrates the merits of fast response speed and high-power density from the SMES-based scheme, and the merits of low capital cost and high-energy density from the BES-based scheme.

This article describes a facile synthesis of a new series of symmetrical bis(arylethynyl)benzene derivatives via a one-pot coupling reaction between trialkylsilyl protected arylalkynyes and aryldihalides bearing both electron-withdrawing (EW) and electron-donating groups (ED) in the presence of PdCl₂(PPh₃)₂(5%) / CuI/tetrabutylammonium fluoride / triethylamine / tetrahydrofuran (sila–Sonogashira reaction) at room temperature.

Dielectric materials with superb thermal and electrical properties are highly desired for high-voltage electrical equipment and advanced electronics. Here, we propose a novel strategy to improve the performance of epoxy composites by employing boron nitride nanosheets (BNNSs) and γ-glycidyl ether oxypropyl sesimoxane (G-POSS) as functional fillers. The resultant ternary epoxy composites exhibit high electrical resistivity (1.63 × 10¹³ Ω·cm) and low dielectric loss (<0.01) due to the ultra-low dielectric constants of cage-structure of G-POSS. In addition, a high thermal conductivity of 0.3969 W·m⁻¹·K⁻¹ is achieved for the epoxy composites, which is 114.66% higher than that of pure epoxy resin. This can be attributed to the high aspect ratio and excellent thermally conductive characteristics of BNNSs, promoting phonon propagation in the composites. Moreover, the epoxy composite simultaneously possesses remarkable dynamic mechanical properties and thermal stability. It is believed that this work provides a universal strategy for designing and fabricating multifunctional composites using a combination of different functional fillers.

With the rapid development of multiterminal high-voltage direct current (HVdc) transmission systems, the research and development of high-speed and stable high-voltage dc circuit breakers have received attention. Among them, mechanical dc circuit breakers based on manual zero-crossing dc breaking technology have been applied in practical projects, owing to their small size, low on-state loss, and low price. However, this method adds a high-frequency current, which deteriorates the magnetic field between the poles of the interrupter when the arc is broken. Therefore, the development of HVdc circuit breakers that maintain high peak magnetic fields and low residual magnetic fields at high frequencies has become the key to the development of multiterminal HVdc transmission. To solve this problem, this article proposes a new interrupter for a vacuum dc circuit breaker based on artificial zero-crossing technology and studies its key characteristics, such as temperature rise, electromagnetic field, and arc column plasma distribution characteristics. The results reveal that the new interrupter proposed in this article has a low-temperature rise, uniformly distributed electric field, high peak value and low remanence of the longitudinal magnetic field, and uniformly distributed plasma in the arc column, and exhibits arc diffusion. Its ability to cope with high-frequency current is significantly higher than that of the traditional cup-shaped axial magnetic field (AMF) contact system interrupter, which is conducive to the high-speed and stable breaking of the interrupter.