Review of thermal transport and electronic properties of borophene

In recent years, two-dimensional boron sheets （borophene） have been experimentally synthesized and theoretically proposed as a promising conductor or transistor with novel thermal and electronic properties. We first give a general survey of some notable electronic properties of borophene, including the superconductivity and topological characters. We then mainly review the basic approaches, thermal transport, as well as the mechanical properties of borophene with different configurations. This review gives a general understanding of some of the crucial thermal transport and electronic properties of borophene, and also calls for further experimental investigations and applications on certain scientific community.

Control of hybrid AC/DC microgrid under islanding operational conditions

This paper presents control methods for hybrid AC/DC microgrid under islanding operation condition.The control schemes for AC sub-microgrid and DC sub-microgrid are investigated according to the power sharing requirement and operational reliability.In addition,the key control schemes of interlinking converter with DC-link capacitor or energy storage,which will devote to the proper power sharing between AC and DC sub-microgrids to maintain AC and DC side voltage stable,is reviewed.Combining the specific control methods developed for AC and DC sub-microgrids with interlinking converter,the whole hybrid AC/DC microgrid can manage the power flow transferred between sub-microgrids for improving on the operational quality and efficiency.

Communication-less harmonic compensation in a multi-bus microgrid through autonomous control of distributed generation grid-interfacing converters

This paper proposes a novel approach to compensate buses voltage and current harmonics through distributed generation(DG)interfacing converter in a multibus microgrid.The control approach of each individual DG unit was designed to use only feedback variables of the converter itself that can be measured locally.In the proposed approach,the adjacent bus voltage is indirectly derived from the measured DG converter output voltage,DG line current and line impedance.A voltage closed-loop controller and a current closed-loop controller are designed to achieve both functions of DG real power generation and harmonics compensation.Therefore,the traditional harmonic measurement devices installed at the bus as well as the long distance communication between the bus and the DG converter are not required.The proposed approach can compensate the current harmonics,mitigate the buses voltage distortion and enable the customer devices to be operated in normal conditions within the multi-bus microgrid,and meanwhile relieve the burden of power quality regulator installed at the point of common coupling.Matlab simulations and experimental results are presented to show the operational effectiveness of the proposed approach.

Abnormal thermal conductivity enhancement in covalently bonded bilayer borophene allotrope

Thermal conductivity of two-dimensional(2D)materials has gained prominence due to the attractive applications in thermal management and thermoelectric devices.In this work,we present a new member of bilayer 2D boron allotropes,denoted as bilayerβ12 borophene,and study the thermal transport properties by solving phonon Boltzmann transport equation based on density functional theory.Based on quantitative chemical bonding analysis,we identify large degrees of covalent bonding of the interlayer interaction.In comparison to its monolayer counterpart,the bilayer exhibits much higher in-plane thermal conductivity despite the lower phonon group velocity and buckling structure,inferring a new physical mechanism.The thermal conductivity(κ)of bilayerβ_(12)borophene at 300 K is 140.5(86.3)W·m^(-1)·K^(-1)along armchair(zigzag)direction,andκ_(armchair)is about 52.7%higher than that of monolayerβ12 borophene.The abnormal enhancement is attributed to the suppressed phonon scattering possibility and elongation of phonon lifetime.More interesting,after forming bilayerβ12 borophene through interlayer covalent bonding,the dominated phonon branch to thermal conductivity changes to transverse acoustic phonons from out-of-plane flexural acoustic(ZA)phonons in the monolayer borophene.Our study elucidates the rich thermal transport characteristics in bilayer covalently bonded 2D materials,and injects fresh insights into the phonon engineering of 2D borophene relevant for emergent thermal management applications.