Low Loss Research Articles

Highly thermally conductive BNNS/PANF dielectric composite boards prepared by a facile compression moulding process

The structural design of an efficient heat conduction channel is critical for heat dissipation in electronic packaging material. The build of oriented boron nitride nanosheet (BNNS) network inside polymers has attracted much attention due to its excellent thermal conductivity and dielectric properties. However, to fabricate a BNNS/polymer composite, complex method and low thermal conductive resin for binding BNNS network are commonly involved, which severely restrict its facile production and enhancement in thermal conductivity. Herein, by utilizing para-aramid nanofibers (PANF) as assistance to BNNS to form thermal conduction network, we obtained high performance composite boards with good formability and adjustable sizes via a simple compression moulding of the BNNS/PANF aerogels. The composite boards exhibit a remarkable in-plane thermal conductivity of 10.62 W/m K−1 at 50 wt% BNNS loading, outstanding practical thermal management capability, excellent thermal stability, low dielectric constant and loss, showing great potential for electronic packaging applications. This facile construction strategy provides a feasible way for the large-scale production and application of high-performance thermal management materials in the future.

Model based analysis of trace metal dosing strategies to improve methane yield in anaerobic digestion systems

Favourable effects of trace metals (TMs) on regulating anaerobic digestion (AD) performance are extensively utilised to improve methane yield. This study discusses a model-based approach to find out the best TM dosing strategies. The model has been applied to compare continuous, preloading, pulse dosing and in-situ loading. Simulations were also carried out to comprehend appropriate dosing form, dosing time and quantity of metals to be dosed. Model results show that the best way to dose TMs is repeated pulse dosing at low concentration levels in the optimum range with high frequency. Best dosing strategy for the system in this study was found to be 5 µM pulse loading at 5 days intervals as it gave maximum methane production and low effluent metal loss. Preferable dosing form depends on reactor configuration and this has been verified after model calibration with experimental data. Easily dissociable metal chlorides are ideal for continuous reactors.

Ultranarrow and multiband perfect absorbers based on dual quasi-bound states in the continuum in near infrared

High quality factor (Q-factor) and multiband perfect absorbers are highly desired in light-harvesting efficiency related optical devices, yet they are always limited by conventional mechanisms like electromagnetically induced transparency, Tamm or plasmonic resonance. In this paper, through constructing the strong coupling between two guided-mode resonances in subwavelength gratings, we propose an ultranarrow and multiband perfect absorber based the dual-band quasi-bound states in the continuum (quasi-BIC) design in near infrared. Benefiting from its angle-dependent characteristic, the device can be straightforwardly utilized for light-switched lamps and optical sensors. Q-factor 8337 and the modulation depth 98.1% are realized while the insertion loss is only 0.07 dB. Compared with its conventional counterparts, the quasi-BIC based absorber enables an excellent hexa-frequency and ultranarrow asynchronous switch function. The quatary-band perfect absorption below 1 nm bandwidth can be applied to the optical sensor to detect four light signals with weak signal strength. This work provides a theoretical basis for multifunctional absorbers with high Q-factor, high modulation depth, and low insertion loss.

A comparative study on the influences of sulfonated- and phosphorated-graphene oxide on polyvinylidene fluoride cation-exchange membranes for electrodialysis

The –SO3H and –PO3H2 groups were grafted on graphene oxide (GO) by adding sulfuric acid and phosphoric acid at the same weight percentage, respectively. The physicochemical properties of the sulfonated GO (SGO) and phosphorated GO (PGO) were compared using different techniques. SGO and PGO were individually incorporated into the PVDF matrix (at the same wt%) to compare their effects on the properties of the resulting PVDF/SGO and PVDF/PGO cation-exchange membranes (CEMs). Membranes' characteristics including ionic conductivity and water content, area resistance, and the rate at which Na+ ions diffuse throughout the membranes changed considerably by altering the type of ion exchange sites, and more desirable values were obtained using PGO. Nevertheless, PVDF/SGO provided an ion exchange capacity (IEC) of 5.5 meq g−1, while it was about 1.7 times lower than PVDF/PGO (9.4 meq g−1). It also provided a promising ionic conductivity (17.24 mS cm−1), transport number (93.65 %), permselectivity (89.58 %), and low area resistance (2.7 Ω cm2), which exceeded those of the commercial CEMs such as Ralex. Moreover, PVDF/SGO exhibited desirable mechanical characteristics, and a low weight loss (2.4 %) and low resistance change (22.2 %) after 9 h being submerged in the Fenton reagent, however, these parameters were better for PVDF/PGO.

Experimental Investigations of Dual Functional Substrate Integrated Waveguide Antenna with Enhanced Directivity for 5G Mobile Communications

Antennas with higher gain and efficiency deliver superior performance across a wide frequency range. Achieving these characteristics at high frequencies while keeping a compact size necessitates sophisticated design approaches. This research presents a substrate-integrated waveguide (SIW) cavity-backed slotted patch antenna (SPA) tailored for the 28 GHz and 34 GHz frequency bands. Additionally, a linear tapered slot antenna is designed with a compact profile of 27.5 mm × 7.5 mm × 0.254 mm. The SIWs are implemented using vias on the outer profile of the antenna, and circular and rectangular slots are etched on the radiating surface. The goal of optimizing the antenna geometry is to enhance return loss within the desired frequency bandwidth, which means the Genetic Algorithm (GA) will determine the optimal antenna shape to achieve lower return loss than the original design within this bandwidth. The antenna exhibits dual resonance at 28 GHz and 38 GHz in the millimeter-wave range, providing an impedance bandwidth of 211 MHz (27.72 GHz to 27.94 GHz) at 28 GHz and 127 MHz (37.88 GHz to 37.98 GHz) centered at 38 GHz. The proposed antenna demonstrates gains of 8.04 dBi and 9.72 dBi at these operating bands. A prototype of the antenna is fabricated on RT/duroid 5880 and its characteristics are measured. The overall VSWR of the antenna ranges from 1 to 2, with a radiation efficiency of 94%. The proposed antenna achieves dual-band performance with increased directivity and stable gain, exhibiting enhanced electric field distribution, radiation patterns, and reflection coefficient (S11), all of which contribute to a comprehensive understanding of the antenna's performance. This study compares the designed antenna's performance to that of the fabricated prototype. The proposed antenna is ideal for 5G applications due to its small size, broad spectral coverage, and excellent gain..

A manganese doping deficient cerium base metal organic framework as radical scavenger for highly-durable proton exchange membrane water electrolysis

Eliminating hydrogen peroxide and free radicals from electrochemical reactions is crucial for mitigating chemical degradation and improving the durability of proton exchange membranes (PEMs). Herein, we prepare a metal–organic framework containing manganese and cerium ions that possesses oxygen vacancy defects and amino functional groups. The prepared Ce4MnBDC-NH2 acts as a catalyst for H2O2 decomposition and as a free radical scavenger, and it is incorporated into a perfluorosulfonic acid (PFSA) ionomer matrix. Featuring large pore volume, high porosity, and abundant amino groups, the Ce4MnBDC-NH2 is locked in a PEM. The obtained Ce4Mn-NH2BDC@PFSA composite membrane exhibits high dimensional stability, excellent proton conductivity and low high-frequency impedance, yielding a proton conductivity of up to 137 mS cm–1 and superior water electrolysis performance of up to 1.83 V at 3.0 A cm–2. Moreover, the obtained Ce4Mn-NH2BDC@PFSA membrane experiences lower weight loss during the Fenton reaction, a low fluoride-ion release rate, and excellent stability in high current density durability testing: its decay rate is only 5.2 μV h–1, which is lower than that of CeO2@PFSA and Nafion 117 membranes. This work provides a promising method to prepare efficient free radical scavengers for steady-state PEM water electrolysis.

Full Title: Outcomes of a single transverse chest roll for prone positioning technique during percutaneous nephrolithotomy (PCNL)

ObjectiveTo compare anesthetic parameters using a novel prone single transverse chest roll technique (STR) to the standard thoraco-pelvic dual transverse roll technique (DTR). MethodsA retrospective review of 441 patients who underwent PCNL between 2018 to 2022 was performed. A total of 4 surgeons were included—surgeon 1 utilized the STR technique while surgeons 2, 3, and 4 used the DTR technique. Anesthetic parameters including end tidal CO2 (ETCO2), mean arterial pressure (MAP), peak airway pressure (Ppeak), plateau airway pressure (Pplat), positive end expiratory pressure (PEEP), oxygen saturation (SpO2), and tidal volume (TV) were compared between both groups at 0 (supine), 15, 30, and 60 minutes post-intubation intervals. Mixed effects regression models with interaction and pairwise comparisons were made between both groups (p<0.05). ResultsA total of 581 PCNLs were performed with 199 using STR and 382 using DTR. Surgery duration, ASA class, and age were similar amongst the STR and DTR groups. Estimated blood loss (59cc vs 83cc, p=0.007) and length of stay (77 hrs vs 163 hrs, p=<0.001) was significantly lower in the STR group. There was a significantly lower Ppeak, Pplat and TV in the STR compared to DTR group at 0, 15, 30, and 60 minutes (p<0.001). ConclusionUsage of a single transverse chest roll during prone PCNL appears to be a safe positioning method. STR patients had lower Ppeak and Pplat at all timepoints, which has been shown to be predictive of lower blood loss.

Novel phosphorous-containing epoxy thermosets with improved anti-flammability, smoke suppression, and dielectric properties

As one of the most commonly used thermosetting resins, the flammability of epoxy resins (EPs) has become a key factor limiting the expansion of their application range. Herein, a novel phosphorous-containing epoxy monomer (EDPPO) was synthesized using diallyl amine and diphenyl phosphoryl chloride as the starting materials. Subsequently, EDPPO was thermally cured with two diamine hardeners, 4, 4′-diaminodiphenyl sulfone (DDS) and 4,4′-dithiodianiline (DTDA). Additionally, commercial diglycidyl ether of bisphenol A (DGEBA)-type epoxy pre-polymers were cured with DDS and DTDA as comparative samples. The cured EDPPO-based thermosets showed excellent flame-retardant properties coupled with smoke suppression. Specifically, the limiting oxygen index (LOI) for the EDPPO/DDS (P content 6.4 wt.%) reached 32.0 %, and the UL-94 vertical burning test reached a V-0 rating. In addition, the PHRR, THR, and TSP values of EDPPO/DDS were 61.6 %, 49.1 %, and 58.5 % lower than those of DGEBA/DDS, respectively. The flame retardant mechanism analysis indicated that the excellent flame retardancy for cured EDPPO-based thermosets was attributed to the combined modes of action in condensed (promoting the charring capacity) and gaseous phases (quenching the active radicals). More importantly, EDPPO/DDS and EDPPO/DTDA exhibited lower dielectric constant and dielectric loss than DGEBA/DDS and DGEBA/DTDA. This work provided novel phosphorous-containing epoxy thermosets with improved anti-flammability, smoke suppression, and dielectric properties.

Comparison of Da Vinci robotic-assisted with open Kasai portoenterostomy for biliary atresia

BackgroundRobotic-assisted Kasai portoenterostomy (RAKPE) has been used to treat biliary atresia (BA). This study aimed to compare the efficacy of RAKPE and open Kasai portoenterostomy (OKPE) for BA. MethodsThirty-one children with type III BA who underwent surgical treatment in two centers from January 2022 to December 2023 were retrospectively collected. According to the operative techniques, the participants were divided into the RAKPE group (13 cases) and the OKPE group (18 cases). The operative time, jaundice clearance (JC) rate, and incidence of cholangitis were analyzed. ResultsThe operative time in the RAKPE group (204.3 ± 19.9 min) was significantly longer than that in the OKPE group (186.2 ± 22.2 min), P<0.05. However, the blood loss (8.1 ± 2.5 ml) in the RAKPE group was significantly decreased compared with the OKPE group (13.6 ± 4.8 ml), and 15.4% patient need blood transfusion in RAKEP group was litter than that 55.6% in the OKPE group, P<0.05. The time to oral feeding (2.8 ± 0.4 days vs. 4.3 ± 0.7 days) and the time to pass ICG-positive stools (3.6 ± 0.6 days vs. 4.7 ± 0.9 days) in the RAKPE group were significantly shorter than those in the OKPE group, P<0.05. No significant differences were observed in the bile excretion rate, hospital stay time, and JC rate. The incidence of cholangitis in the RAKPE group was significantly lower than that in the OKPE group during short follow-up. ConclusionRAKPE may be associated with lower intraoperative blood loss, decrease need for postoperative transfusions and decreased rate of postoperative cholangitis compared to OKPE. Level of evidenceIII

Investigating the potential of Nd and Co modified bismuth ferrite (BiFeO3) nanoparticles for advanced energy storage and electronic applications

In this study, we synthesized and characterized Nd and Co modified bismuth ferrite nanoparticles (BNFCO) using mechanical milling. X-ray diffraction (XRD) analysis has provided confirmation of the distorted rhombohedral, mixed rhombohedral-tetragonal and tetragonal perovskite structure with space group R3c and P2mm. Notably, these nanoparticles exhibited a high dielectric constant and low loss values at low frequencies and high temperatures, remaining around 103 up to 373 K before increasing to approximately 104, which opens new avenues for exploring temperature-sensitive dielectric properties. The AC conductivity adhered to Jonscher's power law, with dc conductivity values ranging from 10−5 to 10−3 s/cm, representing a significant advance in understanding electrical conduction in nanomaterials. Furthermore, we assessed the electrochemical behavior of the fabricated samples at varying concentrations using cyclic voltammetry, Galvanostatic charge and discharging (GCD), and electrochemical impedance spectroscopy (EIS) on a modified electrode. BNFCO (0.20) displayed exceptional properties with a capacitance of 510 F g−1 and a capacitance retention of 93.9 % after 5k cycles, making BNFCO nanomaterials potential candidates for supercapacitor applications. The multifunctional properties of Nd and Co modified bismuth ferrite nanoparticles presented in this study offer unparalleled opportunities for transformative applications in supercapacitors and optoelectronic devices.

Low loss ridge waveguides on the hybrid single crystalline silicon and lithium niobate thin films

The hybridization of silicon (Si) thin film and lithium niobate (LN) thin film with remarkable properties, including the excellent optical properties of LN, excellent electrical properties and mature processing advantages of Si, can provide an important material platform for integrated photonic applications. In this work, a 4-inch single crystalline Si thin film wafer was prepared using wafer bonding, grinding and polishing techniques on LN thin film substrate. The films were characterized by using high-resolution transmission electron microscopy (HRTEM). The interplanar spacings and strain of Si film were calculated by analysis of high-resolution X-ray diffraction (HRXRD). Si ridge straight waveguides were fabricated on the hybrid thin films, and the transmission loss was 1.2dB/cm. The near-field mode distribution of the waveguide was investigated by combining FDTD (Finite-Difference Time-Domain) simulation and end coupling measurement.

Synergistic effect of Ni(OH)2 and MXene nanosheets in 3D framework on the improvement of dielectric, energy storage, mechanical and thermal characteristics of polyvinylidene fluoride(PVDF) polymeric composites

This work introduces a novel method for incorporating meticulously designed nanohybrids to improve the dielectric characteristics of polymer composites. Conventional ceramic fillers have problems with dispersion even if they are good at increasing permittivity. Here, we overcome this constraint by creating nanohybrids made of MXene, polyvinylidene fluoride (PVDF), and single-layered and three-dimensional Ni(OH)2. An essential coupling agent, polyethyleneimine (PEI), fosters a robust electrostatic connection between Ni(OH)2 and superior adhesion with MXene. Using only 9.5 wt percent filler loading, we are able to achieve a low loss tangent (tan δ=0.4) at 1 kHz with a considerable permittivity improvement (ε=1000) thanks to this creative design. The nanohybrid structure's ability to promote longer interfacial contact is crucial to this enhancement. Moreover, the integrated Ni(OH)2 layer functions as a semiconductor, obstructing the passage of current through the MXene flakes and lowering conductivity overall. At a low Ni(OH)2/MXene loading of 1.5 wt%, our three-phase composites also show higher dielectric strength (248.68 MV/m). Specifically, the synergistic coupling of MXene with Ni(OH)2 provides notable increases in mechanical and thermal properties. The tensile strength and Young's modulus of these films are much higher than those of virgin PVDF and Ni(OH)2-modified composites.

The role of professional calling and student cyberbullying on teachers’ presenteeism and productivity loss.

The teaching profession has always been recognised as one that requires a greater vocational calling. However, education professionals have had to adapt to and manage phenomenons which have arisen due to more demanding work contexts that require them to participate in work, even when they are ill (presenteeism), and to a global-wide digital transformation. Such phenomenons include cyberbullying, which has proliferated in school environments. It is crucial to understand the impact this type of phenomenon can have on these professionals. Accordingly, the main objective of this study was to identify the needs felt by teachers to deal effectively with incidents of cyberbullying and its potential impact on and reduce presenteeism. Two studies were developed, with the intention that the hypotheses posed by the quantitative study could be enriched with the inferences drawn from the qualitative study. A sample of 542 middle school teachers responded to questionnaires and 63 participated in interviews. The results showed that teachers’ professional calling led to a lower loss of productivity, due to a lower frequency of presenteeism. This effect was more pronounced in the presence of cyberbullying observation. This study provides a contribution to the calling and presenteeism literature since it focuses on the impact of observing cyberbullying on sickness presence. It is relevant because by knowing the demands that teachers feel and the resources they lack, it is possible to implement tailored intervention and prevention programs to help professionals deal with cyberbullying.

Effect of temperature on the rheological, textural, and sensory properties of butters from New Zealand market.

Texture and sensory studies at various temperatures are important in evaluating and improving the functionality of butter. While literature is scarce, we evaluated and compared the effect of temperature (5-25°C) on the texture, rheological and sensory properties of commercial butter samples (salted, unsalted, cultured, and spreadable) from the New Zealand market. In addition, the instrumental analyses were compared with the sensory evaluation, to understand the possibility of using instrumental analysis to evaluate consumer liking for different butters. Butter type, temperature, and their type-temperature interaction exhibited significant differences for all instrumental textural parameters. As expected, higher temperature produced softer butter that was more spreadable, liquid-like, less adhesive, less cohesive, had lower storage modulus (G') and lower loss modulus (G″) with the melting of milk fat crystals; however, the rate of change varied for the different butter samples. We have established meltability as the parameter for evaluating butter selection for different applications. The spreadable butter sample exhibited the lowest hardness and G', and highest spreadability (p < .05) at all temperatures, owing to its low solid fat content and the abundance of low-melting triglycerides. The cultured butter sample had the highest melting point, owing to compositional differences. The instrumental and sensory texture analyses were highly correlated, indicating the comparative effectiveness of both approaches for studying the effects of different temperatures on butter textural properties. Overall, our findings provide detailed reference to the dairy industry for butter manufacture, considering variation in fatty acid composition, texture analysis, rheology, and sensory analysis, over the range of storage/usage temperatures.

Broadband Eight-Way High-Isolation Cavity Power Divider with Low Insertion Loss for MIMO Communication Systems

Broadband Eight-Way High-Isolation Cavity Power Divider with Low Insertion Loss for MIMO Communication Systems

Multi-site EEG studies in early infancy: Methods to enhance data quality

Brain differences linked to autism spectrum disorder (ASD) can manifest before observable symptoms. Studying these early neural precursors in larger and more diverse cohorts is crucial for advancing our understanding of developmental pathways and potentially facilitating earlier identification. EEG is an ideal tool for investigating early neural differences in ASD, given its scalability and high tolerability in infant populations. In this context, we integrated EEG into an existing multi-site MRI study of infants with a higher familial likelihood of developing ASD. This paper describes the comprehensive protocol established to collect longitudinal, high-density EEG data from infants across five sites as part of the Infant Brain Imaging Study (IBIS) Network and reports interim feasibility and data quality results. We evaluated feasibility by measuring the percentage of infants from whom we successfully collected each EEG paradigm. The quality of task-free data was assessed based on the duration of EEG recordings remaining after artifact removal. Preliminary analyses revealed low data loss, with average in-session loss rates at 4.16 % and quality control loss rates at 11.66 %. Overall, the task-free data retention rate, accounting for both in-session issues and quality control, was 84.16 %, with high consistency across sites. The insights gained from this preliminary analysis highlight key sources of data attrition and provide practical considerations to guide similar research endeavors.

Highly sensitive photonic crystal fiber chemical sensor for detecting carbon disulfide and bromoform in the THz regime

In this study, an innovative photonic crystal fiber (PCF) designed specifically for the detection of carbon disulfide and bromoform liquid chemicals within the THz frequency range was introduced. The PCF’s structural design was achieved using the Finite Element Method (FEM) and Perfectly Matched Layer (PML) boundary conditions within COMSOL Multiphysics, ensuring precision through appropriate numerical parameters. Six distinct configurations were developed, incorporating circular, square, rectangular slotted, benzene-shaped circular, and two elliptical core designs, as well as an eight-elliptical core design. The PCF models were constructed utilizing the dielectric material TOPAS for accurate simulation and analysis. Various crucial parameters of the proposed PCF were examined across a wide THz spectrum spanning from 0.2 to 1.2 THz. The PCF model exhibited a peak output at the operating frequency of 0.8 THz for the square-shaped core design, achieving a relative sensitivity of 96.891% for bromoform and 95.603% for carbon disulfide. Remarkably low material losses of 0.0081104 cm−1 for bromoform and 0.006703 cm−1 for carbon disulfide were observed, along with a core power fraction of 93.107% for bromoform and 94.263% for carbon disulfide. The effective area was determined to be 1.77 × 10−07 μm2 for bromoform and 1.70 × 10−07 μm2 for carbon disulfide, while the confinement loss measured 2.25 × 10−17 dB/cm for bromoform and 4.76 × 10−17 dB/cm for carbon disulfide. These superior attributes strongly suggest that this model will be crucial in applications like supercontinuum generation, sensing, and biomedical imaging.

Development and characterization of PVA-based nanocomposites with graphene and natural quartz nanoparticles for energy storage applications

This study presents the development and characterization of polymer nanocomposites (PNCs) using polyvinyl alcohol (PVA) as a matrix, incorporating graphene (Gr) and natural quartz nanoparticles (NQNs) as nanofillers. The graphene content was fixed at 1 wt%, while the quartz content was varied at 3 wt%, 7 wt%, and 11 wt%. The NQNs were derived from natural quartz rocks, which were ground and milled to nanosize, emphasizing the utilization of natural materials. Comprehensive characterization was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), UV–visible spectroscopy (UV–Vis), and extensive electrical and dielectric measurements. SEM and EDS analyses revealed the nearly spherical shape of the NQNs, with sizes ranging from 25 to 88 nm and an average size of 61.2 ± 13.1 nm. XRD patterns indicated a decrease in crystallinity of the polymer matrix with increasing NQNs content, with the PVA/Gr-11 wt% NQNs showing nearly amorphous characteristics. FTIR spectra demonstrated the incorporation of NQNs within the PVA matrix, affecting the chemical bonding and reducing the intensity of characteristic peaks. UV–Vis spectra indicated a significant decrease in the optical bandgap with the addition of NQNs, suggesting enhanced electronic properties. The electrical conductivity measurements, at a frequency range of 50 Hz to 8 MHz and temperature range from 20 °C to 80 °C, showed that the incorporation of Gr, a two-dimensional (2D) material, and NQNs significantly enhanced the conductivity of the nanocomposites, with the optimal performance observed at 7 wt% NQNs. Dielectric measurements revealed that the PVA/Gr-7 wt% NQNs nanocomposite exhibited superior dielectric properties, with higher dielectric constant and lower dielectric loss compared to pure PVA. Nyquist plots indicated reduced bulk resistance and enhanced thermal stability for the PVA/Gr-7 wt% NQNs composite. Capacitance-frequency and conductance-frequency analyses of the fabricated capacitor confirmed this composite's superior performance for dielectric capacitors. The optimized PVA/Gr-7 wt% NQNs nanocomposite, leveraging the unique properties of natural quartz and 2D graphene, demonstrated significant improvements in electrical and dielectric properties, making it a promising candidate for advanced dielectric capacitors in energy storage applications. The study confirms the innovative use of natural and 2D materials to develop energy storage devices.

Integrated battery thermal and energy management for electric vehicles with hybrid energy storage system: A hierarchical approach

Battery cooling is crucial for electric vehicles’ thermal safety, energy consumption, and battery life in hot climatic conditions. For electric vehicles with battery/supercapacitor hybrid energy storage system, battery cooling is deeply coupled with load power split from the electrical-thermal-aging perspective, leading to challenging thermal and energy management issues. This paper proposes a hierarchical multi-horizon model predictive control (MH-MPC) method to optimize battery cooling and energy management simultaneously. First, the electrical-thermal-aging coupling relationship between battery cooling and energy management is systematically analyzed. Then, by decoupling a centralized MH-MPC, an upper-level MH-MPC is designed to optimize the battery capacity loss cost and battery cooling cost by generating optimal compressor power, then a lower-level MH-MPC tends to minimize the battery capacity loss cost by allocating the total load power demand. The prediction horizon and sampling time are determined. Numerical results show that, compared with the centralized method, the proposed hierarchical method provides a lower battery capacity loss for long-term driving with only about 20% computation burden. Compared with standalone energy management without battery cooling, the total cost can be reduced by 12%–16% under long-term driving. Compared with optimizing energy management with Bangbang cooling, the battery degradation and total costs can be reduced by 15%–52% under short-term driving without deteriorating long-term performance.

Significantly enhanced dielectric properties of Ti3C2Tx MXene/MoS2/methylvinyl silicone rubber ternary composites by tuning the particle size of MoS2

AbstractTo realize the great potential of silicone rubber in advanced electronics, high dielectric constant and low loss tangent are currently pursued. Adding a third phase to conductive filler/silicone rubber composites may enhance the properties of the composites, but the appropriate particle size of the third phase is an open question. Here, MoS2 was used as the third phase to prepare the Ti3C2Tx MXene/MoS2/methylvinyl silicone rubber (VMQ) ternary composites, and the influence of different sizes of MoS2 (200 nm and 2 μm) on the dielectric performance of the composites was investigated. The dielectric constant of the Ti3C2Tx MXene/VMQ composites with 5 wt% MoS2 nanoparticles shows a 279% enhancement from 2.78 to 7.75 at 103 Hz, better than that of the Ti3C2Tx MXene‐MoS2 hybrid fillers/VMQ composites. Compared with micron MoS2, nano MoS2 can significantly enhance the dielectric performance of conductive filler/polymer composites because of shorter interparticle distances and enhanced interfacial polarization. Meanwhile, the composites exhibit low loss tangent (lower than 0.0015) and good thermal stability (up to 400°C) because of the low filling amounts of Ti3C2Tx MXene and MoS2 nanoparticles. Excellent flexibility with Young's modulus of 285 kPa and elongations break of 446% was also obtained. The design of these ternary composites greatly improves the dielectric and mechanical properties, which means that the dielectric material has a broad application prospect in modern electronics industry.Highlights High dielectric constant was gained in Ti3C2Tx MXene/5n‐MoS2/VMQ composites. The MXene/5n‐MoS2/VMQ composites exhibited excellent mechanical properties. Appropriate filler size can benefit the performance of polymer composites.