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This paper presents an optimization model for the location and capacity of electric vehicle (EV) charging stations. The model takes the multiple factors of the “vehicle–station–grid” system into account. Then, ArcScene is used to couple the road and power grid models and ensure that the coupling system is strictly under the goal of minimizing the total social cost, which includes the operator cost, user charging cost, and power grid loss. An immune particle swarm optimization algorithm (IPSOA) is proposed in this paper to obtain the optimal coupling strategy. The simulation results show that the algorithm has good convergence and performs well in solving multi-modal problems. It also balances the interests of users, operators, and the power grid. Compared with other schemes, the grid loss cost is reduced by 11.1% and 17.8%, and the total social cost decreases by 9.96% and 3.22%.

Accurate prediction of electric vehicle (EV) charging loads is a foundational step in the establishment of expressway charging infrastructures. This study introduces an approach to enhance the precision of expressway EV charging load predictions. The method considers both the battery dynamic state-of-charge (SOC) and user charging decisions. Expressway network nodes were first extracted using the open Gaode Map API to establish a model that incorporates the expressway network and traffic flow features. A Gaussian mixture model is then employed to construct a SOC distribution model for mixed traffic flow. An innovative SOC dynamic translation model is then introduced to capture the dynamic characteristics of traffic flow SOC values. Based on this foundation, an EV charging decision model was developed which considers expressway node distinctions. EV travel characteristics are extracted from the NHTS2017 datasets to assist in constructing the model. Differentiated decision-making is achieved by utilizing improved Lognormal and Sigmoid functions. Finally, the proposed method is applied to a case study of the Lian-Huo expressway. An analysis of EV charging power converges with historical data and shows that the method accurately predicts the charging loads of EVs on expressways, thus revealing the efficacy of the proposed approach in predicting EV charging dynamics under expressway scenarios.

Wind turbine generator output cables are subjected to alternating torsional loads during long-term operation, combined with electrothermal stress, which may lead to insulation failure and other serious issues. Currently, the electrothermal aging mechanism under torsional stress is not fully understood. This study explores the synergistic degradation mechanism of electrothermal aging and nonlinear torsion by constructing a multi-stress aging test platform in the laboratory environment. This study involved accelerated aging tests with thermal, electrothermal, and electrothermal–torsional alternating stresses. The aged cable samples were analyzed for their physical and chemical properties using differential scanning calorimetry and Fourier transform infrared spectroscopy, while dielectric spectroscopy and mechanical tests were employed to evaluate their dielectric and mechanical performance. The results indicate that torsional stress induces physical changes at the molecular level in the ethylene–propylene rubber (EPR), leading to reduced strength, hardening, and increased brittleness, resulting in decreased mechanical strength. In addition, torsional stress promotes oxidation reactions and chain scission processes in the insulation layer, reducing crystallinity and causing a decline in mechanical performance. Increased oxidation and chain scission reactions result in an increase in polar groups, leading to an increase in the dielectric loss factor of the EPR. The findings of this study provide valuable insights for the design, manufacturing, and operational monitoring of wind turbine generator output cables.

Abstract Background The treatment of completely displaced midshaft clavicle fractures is still controversial, especially Robinson 2B fractures. Titanium elastic nail (TEN) fixation is a good option for simple fractures, but no reports exist on its use in complex fractures. This study aimed to present a surgical method using the Nice knot-assisted TEN fixation to treat Robinson 2B midshaft clavicular fractures. Methods A retrospective analysis of 29 patients who underwent fixation with TEN and had a 1-year postoperative follow-up between 2016 and 2020 was performed. The fractures were classified as Robinson type 2B1 in 17 cases and type 2B2 in 12 cases. Length of the incision, postoperative shoulder function Disability of Arm Shoulder and Hand (DASH) score and Constant score, complications rate, and second surgical incision length were recorded. Results The length of the incision was 2–6 cm (average 3.7 cm). All incisions healed by first intention, and no infection or nerve injury occurred. The Constant score was 92–100 (average 96) and the DASH score was 0-6.2 (mean, 2.64). TEN bending and hypertrophic nonunion occurred in one case (3.4%) and implant irritation occurred in four cases (13.8%) Fixation implants were removed at 12–26 months (mean, 14.6 months) after surgery, and the length of the second incision was 1-2.5 cm (average 1.3 cm). Conclusions Intramedullary fixation by TEN is approved as a suitable surgical technique in clavicular fracture treatment. Nice knot-assisted fixation provides multifragmentary fracture stabilization, contributing to good fracture healing. Surgeons should consider this technique in treating Robinson 2B midshaft clavicular fractures. Trial registration Retrospectively registered. This study was approved by the Ethics Committee of Wuxi Ninth People’s Hospital (LW20220021).

Abstract Complex lower extremity trauma reconstruction remains a challenge. This study used an internal fixation composite structure of antibiotic cement plates as a temporary fixation to treat lower extremity Grade III open fractures; thus, reducing the treatment period and complications of external fixation. We aimed to assess the safety and efficacy of this technique in the initial surgery stage. Between January 2018 and March 2021, 20 patients with Gustilo grade IIIB/C open fractures received an antibiotic cement-coated locking plate as a temporary internal fixator during initial surgery. Thorough debridement and temporary internal fixation were performed with a 3.5-mm system antibiotic cement-coated locking plate. Ten patients required free bone fragment removal, followed by bone cement packing. The final stage involved internal fixation and wound repair with a free anterolateral thigh flap. Clinical and imaging results were retrospectively analysed. The repair time ranged 1–7 days. All flaps survived. Two patients experienced wound infection, and one developed severe bone infection 3 months after three-stage bone graft surgery. Autologous cancellous bone grafting was performed on 10 patients with bone defects 6 weeks after surgery. Bone union was universally achieved after 1 year. This method proved safe and effective, successfully repairing Grade III open fractures of the lower extremity 1–7 days post-treatment.

Abstract Composited cable terminals are critical for reliable power delivery of traditional and traction power supply systems. During its operation, the cable terminal continually undergoes complex circumstances where humidity, temperature, field strength, mechanical stress and other factors continuously change at different levels. In extreme cases, defects or even failures may occur in the cable terminals, leading to catastrophic accidents. This makes the condition monitoring and defect detection of composited cable terminals become an imperative need for the power industry. The “state‐of‐the‐art” technology of cable terminal condition assessment is focussed and a systematic review of the current research progress of cable terminal condition assessment from the operation circumstances to failure mechanisms is provided. It covers both online/offline condition monitoring methods and defects detection approaches. In addition, challenges and future research directions for cable terminal condition assessment are also addressed. It is concluded that the non‐destructive and non‐intrusive methods like terahertz imaging and ultrasonic testing, and multi‐source information fusion methods as well as the digital twin technology have been gaining popularity for cable terminal defect inspection. It is expected the presented work can provide a global field of vision for further advancement of both scholars and industrial engineers in this field.

Developing efficient anodes for H2O2 production via water oxidation remains challenging. Here, the authors report a ZnGa2O4 anode with dual active sites to improve the selectivity and to resist the decomposition of H2O2, and the peak faradaic efficiency reaches 82% at a low potential.

Streamer discharge theory does not consider the influence of airflow on discharge. However, it is found experimentally that the airflow causes a great change in the breakdown process, especially in a nonuniform field. In this paper, a physical model of spark discharge in airflow is established considering the combined effect of the decrease in airflow density and the blowing away of positive ions and electrons on the breakdown process. Furthermore, the classic streamer breakdown criteria both in uniform field and nonuniform field are modified. This model extends the classic streamer breakdown criterion for static gases to the airflow environment.

In this paper, we proposed a cavity containing an intracavity medium of five-level double-ladder-type atoms with electromagnetically induced transparency to enhance Goos-Hänchen shifts of reflected and transmitted light beams. The dependence of the Goos-Hänchen shifts has been analyzed. It is shown that Goos-Hänchen shifts can be controlled by modifying the intensity and detuning of the coherent control field without changing material and the structure of the dielectric interface. This work has considerable potential for applications such as optical devices in information processing, flexible optical-beam steering and alignment, optical sensors and optical switches.

To realize the low-carbon operation of integrated energy systems (IESs), this paper proposes a low-carbon optimal scheduling method. First of all, considering the integrated demand response of price-based electricity and heating, an economic scheduling model of the IES integrated demand response based on chance-constrained programming is proposed to minimize the integrated operating cost in an uncertain environment. Through the comprehensive demand response model, the impact of the demand response ratio on the operating economy of the IES is explored. Afterward, the carbon emission index is introduced, and gas turbines and energy storage devices are used as the actuators of multi-energy coupling to further explore the potential interactions between the coupling capacities of various heterogeneous energy sources and carbon emissions. Finally, the original uncertainty model is transformed into a mixed-integer linear-programming model and solved using sequence operation theory and the linearization method. The results show that the operating economy of the IES is improved by coordinating the uncertainty of the integrated demand response and renewable energy. In addition, the tradeoff between the working economy and reliability of the EIS can be balanced via the setting of an appropriate confidence level for the opportunity constraints.

With the rapid development of large-scale distributed renewable energy in China, the load factor of distribution transformer increases year by year, this directly become a new challenge to the load capacity of the transformer. Once subjected to this condition for a long time will have an impact on the hotspot temperature and consequently, the useful life of the transformer. In this regard, load capacity assessment of the distribution transformer becomes an essential work for unit upgrading or even replacement. This article systematically summarized the evaluation methods of transformer load capacity, as well as the load capacity prediction and dynamic capacity enhancement strategies of transformer. Discussions for the future work regarding this topic are also carried out.

We numerically and experimentally demonstrate an electromagnetically induced transparency analogue (EIT-analogue) planar metamaterial. The proposed metamaterial cell adopts a double patterned concentric hexagon ring and can be manufactured easily. The bandwidth of the transmission window can be tuned by changing the separation distance of two hexagon ring. The coupling mechanism of the EIT-analogue metamaterial is studied by analyzing transmission response and magnetic field distribution. The achievement of EIT-analogue effect in this system is two bright modes coupling, which is different from bright-dark modes coupling. A polarization-independent and angle-insensitive sharp transmission response is obtained at microwave frequencies. A coupled oscillator theoretical model is used to demonstrate the resonance transmittance mechanism of the proposed EIT-analogue metamaterial.

Abstract With the increasing demand for small-scale photodetector devices, quantum dot–based infrared photodetectors have attracted more and more attention in the past decades. In this work, periodic metal nanohole array structures are introduced to the quantum dot infrared photodetectors to enhance the photon absorptivity performance via the surface plasmon enhancement effect in order to overcome the bottleneck of low optical absorption efficiency that exists in conventional photodetectors. The results demonstrate that the optimized metal nanohole array structures can greatly enhance the photon absorptivity up to 86.47% in the specific photodetectors, which is 1.89 times than that of conventional photodetectors without the metal array structures. The large enhancement of the absorptivity can be attributed to the local coupling surface plasmon effect caused by the metal nanohole array structures. It is believed that the study can provide certain theoretical guidance for high-performance nanoscale quantum dot–based infrared photodetectors.

Abstract Background Despite advances in microsurgical techniques of flap transfer, complex upper extremity trauma reconstruction remains a challenge for surgeons. This study aimed to present the outcomes in using flaps in the subacute reconstruction of complex upper extremity injuries. Methods From July 2013 to December 2016, 35 patients ranging in age from 23 to 69 years with complicated upper extremity traumatic injuries were treated using flap reconstruction in subacute period. The number and causes of injury were 12 machine crush injuries, 18 machine strangulation injuries, two chainsaw accidents, two traffic accidents, and one incident of heavy bruising. Thirty-five patients underwent flap procedures, including 24 anterolateral thigh flaps (68.57%), five latissimus dorsi flaps (14.29%), and six lateral arm flaps (17.14%). Flap sizes ranged from 3 × 4 to 42 × 16 cm2. The mean time of flap reconstruction was 14 days (range 5–29). During postoperative follow-up, flap appearance, sensory recovery, scarring and satisfaction were assessed. Results The overall flap survival rate was 94.3%.Two flaps developed partial necrosis, both of which were later treated with skin grafting. Traumatic wound infections occurred in three patients. All upper limb injuries were completely covered. The follow-up periods ranged from 18 to 62 months with an average of 2.9 months. All skin flap textures were soft with varying degrees of pigmentation. Flap sensory recovery was S1 in three cases, S2 in eight cases, S3 in 15 cases, and S4 in nine cases. There were no donor site complications other than three cases with scar hyperplasia. Conclusions The severe upper limb soft tissue defects still achieved satisfactory function and appearance with negligible complications and low amputation rates during the subacute period.

The marine environment in which offshore wind turbines are located is very complex and subjected to a variety of random loads that vary with time and space. As an important component of offshore wind power, the cable also bears the impact of the environment in which most of the turbines are located. Under the long-term action of mechanical stresses such as tension, torsion, and vibration, the cable insulation will crack due to stress fatigue leading to partial discharge, which seriously affects its electrical performance. The study of the mechanism of the change of electrical properties of cable insulation due to mechanical behavior is of great theoretical guidance to improve the reliable operation of cables. This paper first introduces the basic characteristics and operating conditions of torsion-resistant cables and submarine cables. Then the mechanical behavior of the cables is summarized, and the deterioration mechanism and deterioration effect of wind power cable insulation under the influence of multiple factors such as heat, oxygen, and mechanical stress are sorted out. Then, the basic principles of wind power cable operation condition monitoring methods and their characteristics are described. Finally, the relevant methods for the detection of hidden defects inside the insulation are summarized.

A tunable dual-band metamaterial absorber composed of a gold square ring and a metal film separated by a strontium titanate dielectric is investigated. Two resonance peaks at frequencies 0.162 THz and 0.329 THz with over 99% absorbance are realized at room temperature. The maximum ratio between the lattice constant and the resonance wavelength is approximately 8.2%, which is much smaller than that of the formerly reported absorber. When the temperature changes from 150 K to 350 K, the two resonance absorption peaks at approximately 66.2% and 67.8% of the modulation depths are obtained. The effective impedance method and the LC equivalent circuit modelling are used to analyze the absorption mechanism of the proposed absorber. The proposed absorber is not affected by the change in polarization angles at normal incidence. The proposed structure adopts a single patterned square ring, which can be manufactured easily, and extended to other frequencies in applications such as biosensors, monitoring and imaging.

Abstract FeNC materials have shown a promising nonprecious oxygen reduction reaction (ORR) electrocatalyst yet their active site structure remains elusive. Several previous works suggest the existence of a mysterious axial ligand on the Fe center, which, however, is still unclarified. In this study, the mysterious axial ligand is identified as a hydroxyl ligand on the Fe centers and selectively promotes the ORR activities depending on different FeN4C configurations, on which the adsorption free energy of the hydroxyl ligand also differs greatly. The selective formation of hydroxyl ligand on specific FeNC configurations can resolve contradictories between previous theoretical and experimental results regarding the ORR activities and associated active configurations of FeNC catalysts. It also explains the pH‐dependent ORR activities and, moreover, a previously unreported pH‐dependent poisoning kinetics of the FeNC catalysts.

This paper presents a dual-band step impedance resonator (SIR) antenna based on metamaterial-inspired periodic structure of coupled complementary split-ring resonators substrate-integrated waveguide (CSRR-SIW). The antenna supports wireless local area networks (WLAN) bands at 2.4/5.2/5.8 GHz. The CSRRs and two branches of the SIR element are etched on the top and bottom metal surfaces of the substrate. The SIR element produces a fundamental frequency f1 at 2.4 GHz and a second harmonic frequency fs2 at 5.7 GHz. Meanwhile, the CSRRs produces a resonant frequency at high-frequency band around 5.2 GHz, which can be combined with the second harmonic frequency fs2 at 5.7 GHz. The high-frequency bandwidth can then be broadened. The simulated and measured results show that the dual operation bands with bandwidths of 16% from 2.25 GHz to 2.64 GHz and 18.2% from 5 GHz to 6 GHz for |S11|

An experimental study was conducted to investigate the discharge characteristics of short air gap and insulation surface under flame conditions. The influence of ac electric field on flame and the mechanism leading to the reduction of breakdown voltage under flame conditions are analyzed. Results show that under the ac electric field, the flame is deflected to the high voltage electrode, and compared with normal conditions (without flame), the breakdown voltage of the short air gap and the insulation surface is decreased by 74.4% and 70%, respectively. Besides, arc levitation appears at high probability under the flame conditions. Furthermore, the decrease of the breakdown voltage of short air gap and the flashover voltage of insulation surface under the flame conditions are mainly due to the increase of the air conductivity and the decrease of the air density. For the insulating dielectric, the change of the flashover path is also one of the main reasons for the decrease of the flashover voltage.

Gas discharge theory as an important subject has been widely employed to solve various questions related to discharge. However, previous concerns about gas discharge were mainly related to some discharge situations in static gases, which do not consider the influence of airflow on discharge. In this paper, the influence of both the airflow direction that is parallel to the field direction and the airflow velocity on air discharge is studied. The airflow is found to induce an obvious polarity effect, which results in a substantial difference in the breakdown voltage values. Compared with the breakdown voltage in static air, the breakdown voltage in airflow decreases because of the downwind effect and increases because of the headwind effect. The relative mean free path of electrons, the diffusion radius of electrons, and the air density are the three major factors affecting the discharge process, and they change with the airflow direction and airflow velocity. The combined effects of those three factors determine the variation trends in breakdown voltage with airflow velocity. These results can provide guidance for the design and insulation coordination of high-voltage equipment in an airflow environment.