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Recently, wireless power transfer (WPT) technology has become a research hot spot due to its benefit of contactless power transfer. Firstly, for the sake of solving the problem of the small coupling coefficient of traditional orbital wireless power transfer systems, a new structure and control strategy of transceiver coil was proposed, and then the optimal parameters of system transmission efficiency were found out by comprehensive analysis of the LCC-S compensation circuit structure and equivalent circuit, and the correctness of the parameters was verified in MATLAB/Simulink simulation. Finally, an experimental prototype was built, and the experimental findings show that the wireless power transfer system based on LCC-S can realize voltage regulation control, the coupling coefficient is increased by 0.4 compared with the traditional orbital structure, and the transmission efficiency of this system is more than 80%.

Silica is one of the most important reinforcing fillers in the rubber industry. As an excellent reinforcing agent, it can endow rubber with higher tensile strength, elongation at break, elasticity, heat resistance, tear strength, etc., and is widely used in rubber products. BIIR has good air tightness, fatigue resistance, aging resistance, chemical resistance, and good processing performance, so it is widely used in tires and other industries. In this paper, three hydrophobic nano-powder materials, silica airgel, hydrophobic fumed silica and hydrophobic precipitated silica, were added to BIIR during rubber mixing and vulcanization. The effects of three nano-powder materials on the physical and mechanical properties of BIIR were compared. The results show that all three hydrophobic silica nano-powder materials can effectively improve the mechanical properties of BIIR, among which silica airgel has the most significant enhancement effect on the mechanical properties of BIIR. The tensile strength of 40% airgel-reinforced vulcanized rubber can be increased from 2.42MPa to 5.84MPa. The 100% constant tensile stress can be increased from 0.34MPa to 1.04MPa, while the tear strength is high (19.07N/mm), the hardness is extremely high (89HA), and the thermal conductivity is as low as 0.13439 (W/m·K).

High proportion of distributed new energy generation, DG) Connect to the grid to mitigate problems such as fossil energy shortages and the threat of global climate change. However, distributed new energy has the characteristics of fluctuation and uncertainty of output, so it will bring some difficulties to energy consumption after the high proportion is connected to the power grid. Given the above problem, the uncertainty of wind and solar output is considered in this paper to ensure that accuracy and the stability of the power grid operation after a large amount of distributed energy is accessed, with 8,760 hour-by-hour power generation data throughout the year as an input. Three kinds of wind and solar storage system operation control strategies are compared. Using storage battery energy storage method and multiple energy storage methods on the fly surplus storage, coordinated control of the system, and setting different discharge priorities in the energy storage portion, increase real-time and ordered energy consumption.

Coriolis mass flowmeters are resonant meters. In this paper, the intrinsic mode of the CMF300 model Coriolis flowmeter under fluid-structure interaction is calculated numerically, and the excitation mode and Coriolis force mode of the Coriolis mass flowmeter in the working state are analyzed. According to the results of modal analysis, the harmonic response analysis of the flowmeter was carried out, and the displacement, stress, and strain response curves of CMF300 under the action of excitation force of different frequency loads were obtained. It provides ideas for the modeling and design of Coriolis mass flowmeters in the future.

The direct energy balance control strategy is analyzed and combined with the characteristics of supercritical units. The direct energy balance strategy is reconstructed. The reconstructed direct energy balance signal is applied to the boiler master control feedforward in the coordinated control, taking a power plant’s coordinated control system as an example, t. Thus, it is applied to the control of supercritical units, which improves the regulation quality of the control system in a steady and dynamic state, and effectively solves the problems of large fluctuation of mainstream pressure, locked increase, and decrease of load command, frequent withdrawal of coordinated control and unqualified AGC index.

An energy storage capacity allocation method is proposed to support primary frequency control of photovoltaic power station, which is difficult to achieve safe and stable operation after a high proportion of photovoltaic connected to public power grid. In this paper, by taking the photovoltaic power plant containing energy storage as an example, and based on the fluctuation characteristics of photovoltaic power output and the performance requirements of primary frequency control response, the required battery storage capacity of photovoltaic power station for primary frequency control is calculated without considering the power abandonment and power limitation conditions, and the typical case is established based on power system simulation software to verify the reasonableness and effectiveness.

Data and model exchange between SysML (Systems Modeling Language) Modeling tools and other system development tools is a critical aspect of Model-Based Systems Engineering (MBSE). This paper introduces an application of the SysML-centric integration framework, which allows integrating multi-disciplinary engineering models into a SysML Modeling environment. A design practice of helicopter fuel system is then presented to illustrate how to combine the external simulation models within the SysML Models to explore the performance and verify corresponding requirements. In this case, FMI (Functional Mock-up Interface) based co-simulation creates a bridge between SysML Modeling tools and simulation tools in the SysML-centric integration framework. According to the practice, we believe it will significantly improve model consistency and traceability to provide early evaluation of concepts during conceptual design phase.

The anti-icing of aircraft and large wind turbines, where the wall temperature is higher than the fluid temperature, can significantly alter the flow evolution characteristics of the boundary layer. Local heating strategies for the manifold state need to be designed based on the changing characteristics of the flow velocity and temperature field in order to precisely control the heat supply and reduce inefficient energy consumption. In order to obtain accurate heat transfer characteristics of the airfoil’s boundary layer flow, it is necessary to refine the measurement of the boundary layer characteristics during flow and heat transfer. In this paper, wind tunnel experiments are carried out on the NACA2412 model with full surface’s zonal electric heating. The wall surface is equipped with a built-in heater and the temperature of the wall surface is obtained through the corresponding temperature sensor. By studying layer characteristics of the four heated regions, namely the laminar flow region near leading edge, the laminar flow destabilisation region, the transition region and the fully turbulent flow region, and comparing them with the boundary layer characteristics of the unheated airfoil, the effects of the presence of heat sources in different regions on the stability of the flow field and the spatial heat transfer pattern are revealed. The results show that heating in the laminar and turbulent zones maintains the stability of the flow field to a greater extent and achieves better heat transfer strength, while heating in the unstable zone brings forward the turbulence and heating in the fully turbulent zone intensifies the flow separation at the trailing edge of the airfoil. This study can be used as a reference for the design of efficient anti-icing systems on full wing surfaces.

In recent years, large-scale renewable energy equipment has promoted the development of grid-connected converters. Among the existing grid-connected converters, PLL-type grid-connected converters are in an unshakable position in the business. As a key device, PLL also plays an irreplaceable role. However, due to the nonlinear characteristics of PLL itself, traditional linear methods cannot be used for more in-depth research, and the existing methods do not systematically obtain the approximate analytical solution of this kind of nonlinear model. Therefore, based on the PLL-type grid-connected converter model, this paper introduces the nonlinear vibration theory to obtain the approximate analytical solution of the model. Specifically, the dynamic model of a PLL-type grid-connected converter system is obtained through the inherent characteristics of the components. Then the normal perturbation and the averaging method are introduced to derive the approximate analytical solution of the model. Finally, the correctness of approximate analytical solutions is verified through experiments, and the application scenarios of the method are summarized.

Chest computed tomography imaging (CT) has become a diagnostic method for many lung diseases due to its high sensitivity and low missed rate of infection. Convolutional neural network based semantic segmentation model that can assist physicians in auxiliary diagnosis. The existing semantic segmentation models do not work well for lesion segmentation of lung CT images, small lesions are not sensitive, and the contour segmentation is coarse, for which this paper designs a network named Att GGO-Net specifically for lung CT images ground glass opacity(GGO) and Lung consolidation segmentation.The basic encoder-decoder network structure used in this study is the U-Net++ model. After feature mapping is finished at each level of U-Net++, cross attention mechanism is introduced to optimize the semantic information in the decoder layer. Finally, self attention mechanism is added to complete the overall network structure.The extensive attention mechanism will cause the network to have many parameters. To solve the issue of large network parameters, the research substitutes depthwise separable convolution for traditional convolution. The data collection of lung CT scans with ground glass opacity and lung consolidation was used for the experiments. The segmentation performance was compared between Att GGO-Net and three classical medical image segmentation networks, namely, U-Net, U-Net++, and Attention U-Net (Att U-Net). The experimental findings demonstrate that the strategy used in this research has a superior segmentation effect than the comparison method.

This study compares two tools, HSS M42 and TiN Coated twist drill bits, in order to determine which tool has the better material removal rate (MRR). Drill bits were of high speed steel (HSS M42) tool and use of Novel coating of Titanium Nitride on HSS tool in this study. The machining is done on a experimental specimen made of aluminium alloy AA6063. The material removal rate of both tools is measured in CNC drilling on two sets of 20 specimens each. Spindle speed, depth of cut, and feed were all controlled variables. G power 80% used for calculating sample size. SPSS software was used to record and analyse the results for both tools. The average MRR recorded for HSS M42 tool was 14.9803 mm3/s with a Standard deviation value 1.713221. This study has a significance value of 0.037 (p < 0.05) with a g power of 80%. The titanium nitride coated tool had an average MRR of 20.06995 mm3/s and 1.179870 standard deviation. The results were achieved at 0.037 significance, that is lower than 0.05. The titanium nitride coated drill bit has comparatively better MRR than the high speed steel drill bit in no-lubricant and no-coolant drilling circumstances, as per this study.

According to the surface reflection characteristics of carbon fiber reinforced plastics and the geometric characteristics of aircraft panel parts, a robot automatic measurement system based on line laser scanning is designed. The selection criteria of measurement pose and the pre-calibration method of measurement pose based on a laser tracker are given. A 3D reconstruction method of global stitching of large-scale parts based on pre-calibration measurement pose is proposed, Finally, the correctness and effectiveness of the proposed method are verified by measuring typical samples with a prototype system.

Existing sounding rocket flight is probably disturbed by external factors, of which attitude is lack of automatic control function and flight trajectory is not stable, thus the project designed a canard adjustable posture scheme based on PID control algorithm, which can effectively solve the sounding rocket flight stability and flight path anti-interference problem with high efficiency.

Natural gas hydrates are the largest reservoir of natural gas on earth and represent an important solution for the transition from the actual energy scenario to a renewable one. Methane, contained in hydrate reservoirs, can be replaced with carbon dioxide, so that the obtained fuel is neutral in terms of climate-changing emissions and therefore equivalent to renewable energy sources. The experimental tests presented in this paper are devoted to study the CO2-CH4 replacement process in natural gas hydrates in presence of water salt. Test are carried out in a lab scale reactor of 1 l volume. The investigation aims at obtaining data on methane recovery rate, CO2 sequestration, composition of the obtained outlet CO2/CH4 mixture, as well as spatial distribution of hydrates thanks to the analysis of temperature profiles. Temperature analysis is used to determine hydrates’ spatial distribution within the sediment. The number of methane hydrate moles formed with salt water is lower than that with pure water. During CO2 injection, not only CH4-CO2 replacement took place, but also new CO2 hydrate formation. The exchange factor, in fact, ranges from 0.11 to 0.4 for tests with salt.

Preventing the power system from becoming overloaded and under stress to the point where it is on the verge of reaching the limits of its transient stability due to high power consumption. This paper proposed the dynamic security assessment for transient stability using Thyristor controlled series capacitor (TCSC) devices controller. The stability criteria are based on the severity indices for analyzing the fault in the power system. The index uses the time domain analysis simulation, making it easier and simpler to implement for the system operators to better prepare for potential disturbances by anticipating how power systems will behave. The optimal location and parameters setting of the TCSC was determined by Flower Pollination Algorithm (FPA) due to its higher convergence rate. The proposed index is tested on the IEEE 14-bus system and further discusses the effect of a three-phase short circuit fault, different fault locations, and fault clearing method. An analysis is done to determine how the short circuit faults on lines affect the transient voltage stability of the load bus and generator bus in the system. The findings show that by employing TCSC, the voltage drop was acceptable improved and stability margins were greatly increased.

A simplified dynamic model of the rotor-bearing-support system is established considering the influence of pedestal flexibility. The vibration characteristics of the system with a flexible pedestal are analyzed. There are two resonance peaks during the run-up process for this kind of system. It is generally thought that the stiffness difference in the vertical and the horizontal direction is the main cause of the double resonance peak phenomenon. The results of the paper show that the flexible pedestal support also causes the double resonance peak phenomenon. The shaft relative vibration cannot reflect the influence of rotor unbalances well near the resonance zone. In this case, the bearing vibration should be preferred in the balance test. The vibration phenomenon on an actual unit is analyzed as an example.

A comprehensive evaluation of the structure and the nano-mechanical characteristics of single and two-layer nano-structured coatings AlN/Al2O3, TaN/Ta2O5 grown on the surface of metallic materials. The formation of a two-layer structure improves the mechanical and tribological properties of the coating-substrate system, such as the plastic deformation resistance and anti-wear performance. The results indicate that the proposed two-layer nanostructured nitride-oxide coatings based on aluminum and tantalum are promising candidates for biomedical applications.

Melanoma is the most dangerous type of cancer, with a high rate of metastasis. The conventional method of treating skin melanoma is photodynamic therapy, yet this type of phototherapy has several side effects. In addition, the photosensitizers used are relatively expensive and toxic. Thus, developing methods of treating melanoma cancer using laser only is a promising area of research. Here we present in vitro effects in melanoma cell culture after 1265 nm laser irradiation exposure.

Bearing component is the most important component of wind turbine, the harsh operating environment makes the bearing prone to failure, and the maintenance cost is very expensive when a failure occurs. Complex environmental noise brings serious noise pollution to fault samples. In addition, the serious sample imbalance between fault samples and normal samples brings great challenges to bearing fault diagnosis. In view of the above mentioned problems, this paper uses a self-attention mechanism optimization and Wasserstein distance improvement deep convolutional adversarial network model based on self-attention mechanism optimization and Wasserstein distance improvement deep Bearing fault diagnosis method based on the convolution generative Adversarial Network Model (SAW-DCGAN). The experimental results show that W-DCGAN has excellent generating ability and can generate samples like real samples to achieve the balance of samples. The addition of self-attention makes the classification features more expressive, and can accelerate the training speed of the model while having a higher fault diagnosis rate, which verifies the practicability of the method.

Existing research express by processing about the vibration signal of electric transformer cover, the corresponding fundamental frequency amplitude can be obtained, which can be used to dig the specific operation state of the electric transformer. For accurately predicting the amplitude at the fundamental frequency about cover vibration signal of electric transformer, a proposed method based on artificial bee colony is designed. But the basic artificial colony method has some defects, such as slow tracking speed and poor feature description ability. Therefore, in view of the shortcomings of the existing ABC based method, the proposed artificial bee colony method is designed, where an adversarial learning mechanism and optimizing each specific search formula is employed. The proposed ABC method improves the prediction accuracy of electric transformer cover vibration signal’s fundamental frequency amplitude. The sepcific results of experimental introduce the effectiveness of the proposed ABC method.

In this study, ZnO-NiO binary metal oxides were synthesized by pulsed laser deposition regarding applications as gas sensors. The technology was applied in air at atmospheric pressure. A compound target fabricated by partially covering a ZnO pellet by a Ni slice was used for ablation. The structure, morphology, composition, and optical properties of the as deposited samples were studied. It was found that composites consisting of ZnO and NiO were formed during the ablation process in air. Generally, the morphology of the as deposited specimens represented a highly porous nanostructure. The samples’ microstructure indicated that the nanostructures were formed by spherically-shaped crystalline ZnO and NiO nanoparticles. The results demonstrated that the ZnO-NiO fabricated samples possessed a high surface-to-volume ratio with considerable number of components attributed to oxygen-deficient states and to adsorbed species, which makes them suitable for gas-sensing applications.

To address the shortcomings of the particle swarm algorithm in solving the PID controller parameter optimization problem in the late stage, an improved particle swarm algorithm is proposed for solving the problem. The particle swarm algorithm is optimized by introducing a nonlinear decreasing inertia weight adjustment strategy so that the pre-flight speed of the particles does not drop too fast, thus balancing the global search ability of the particles with the local search ability and avoiding falling into a local optimum. Simulation experiments were conducted in Matlab/Simulink using the standard PSO, ZN formula method, and the improved PSO, respectively. The results show that the improved algorithm enhances the stability, convergence speed, and search accuracy of the PID parameters with better performance indicators.

Design of free space polymeric optics for communications is presented. Selection of polymers is accomplished on base of their measured transmission spectra, refractive and dispersive properties. The proposed telescopic system of the transmitter consists of a doublet objective composed of styrenic and acrylic materials and an eye-piece made of carbonate and acrylic polymers to minimise the spherical aberrations. The receiver optics is more precise and is realised as a high aperture Cassegrain objective to collect as much as possible of the incoming light and to couple it to the optical fiber.

Cancerous and precancerous skin conditions occupy one of the leading places in oncology. Early detection of suspects and temporary referrals to a specialist are critical to successful treatment. Numerous optical techniques are used for obtaining a new data from cutaneous neoplasia. Diffuse–reflectance spectroscopy is one of these techniques due to its high sensitivity in detecting subtle tissue alterations. Light scattering events inside the skin tissues change significantly in the development stage of skin lesions. These changes in the tissue scattering properties affect the diffuse reflectance spectrum and provide classification of different skin lesions based on diffuse reflectance measurements. We have investigated diffuse–reflectance spectroscopy for diagnostic of skin lesions and as a result, an optical device for clinical application was developed. The current study shows the obtained results by the prototype device for the reflective ability of pigmented and non-pigmented skin benign, dysplastic, and malignant cutaneous lesions in vivo.

In a distribution power grid with a high proportion of distributed photovoltaic (DP) connections, the real-time acquisition of the distributed photovoltaic power generation data is a costly and heavy task. In this paper, a virtual data sampling method based on Deep Belief Network (DBN) combined with a Second-order oscillating-firefly algorithm (SOO-FA) is proposed. It enables virtual data sampling from all distributed PV plants in a region where only one distributed PV plant has a complete data-sampling device and the other distributed PV plants have less expensive current sampling terminals. The firefly algorithm is utilized to continuously adjust and optimize the weights of the deep belief network, and the optimal DBN model is used to carry out the virtual collection of the power output data of the distributed PV equipment within the region. Finally, the proposed method has high accuracy for the PV output power by 100 distributed PV devices in the regional range in the simulation section.

Composite materials are widely used in the design and manufacture of modern civil aircraft fuselage structures. Some large airliners already have full-size composite fuselages, which reduced the weight of the fuselage structure, but the problem of reinforcing the opening of the composite fuselage is also very important. In this paper, the design of medium and large scale open reinforcement structures in composite fuselages is focused. The force characteristics of passenger doors, cargo doors, landing gear hatch openings, and the reinforcement structure form are elaborated, and based on the current research status at home and abroad, the future development of composite fuselage opening reinforcement design is prospected.

At present, the evaluation results of capacity credit of photovoltaic (PV) power generation are mainly static fixed values that are independent of time. Considering the degradation of the performance of the PV module, the capacity credit should be a time-varying value rather than a static value during the life cycle of the PV power plant. In this paper, the annual performance degradation model of a PV power station is established, and the time-varying capacity credit in the life cycle of the PV plant is simulated by calculating the year-by-year capacity credit. By adding a 100MW PV system to the IEEE-RTS 79 system for a case study, the results are as follows: the PV capacity credit is 46.04% without considering module performance decay, 45.36% in the first year when degradation is considered, and only 31.96% at the end of the life cycle. The average capacity credit over the life cycle is about 38.38%. It shows that the capacity credit varies greatly during the life cycle of PV modules, and cannot be ignored in the evaluation of capacity credit.

The effect of texturing area on the friction properties of partially textured bearing at different rotational speeds was investigated theoretically. Four texturing configurations are limited on the bearing surface from the oil film fracture zone of the smooth bearing (200º to 360º) in the rotational direction with different eccentricity ratios. The results show that the friction coefficient of the partially textured bearing can be reduced compared with the smooth bearing. The friction coefficient decreases greater with the increasing texture depth at the fixed rotational speed. When the texturing configuration starts from the oil film fracture zone at the eccentricity ratio of 0.4 or 0.6, the partially textured bearings perform better at different speeds.

With the rapid development of renewable energy, a large number of renewable energy stations are connected to the power system, which leads to a decrease in the inertia of the power system and an increase in safety risks suffered. Thus, online static security assessment (SSA) is increasingly necessary. However, because of the uncertainty of renewable energy, it is not feasible to check all possible scenarios in online SSA. To reduce the number of calculations and achieve SSA in a short time, a new online SSA method based on scenario clustering for future ultra-short-term security assessment is proposed in this paper. In the offline stage, a key scenario set is constructed by Markov Chain Monte Carlo and K-means with historical data. In the online application, the initial probability distribution of renewable energy outputs is calculated by joint distribution with the output of the previous interval and corrected by weather data. Then load flow calculation with N-1 criteria is executed, and the probability for the safe operation of the system is calculated. The effectiveness of the proposed online SSA scheme has been verified in the IEEE-300 system, where one of the generators is replaced by a renewable energy station.

The wall thickness of the sewage pipeline on a shale gas platform is seriously reduced. In order to explore the specific reasons for the pipeline failure, this paper carried out analysis by means of macroscopic inspection, mechanical property test, chemical composition analysis of base metal and corrosion product analysis. The analysis results show that the site of this pipeline corroded most seriously is at 5 o ′clock and 12 o ′clock near the outlet, and the corrosion of liquid accumulation containing CO2 is the main reason for the serious failure of the inner wall of this pipeline. This paper explores the specific reasons for the failure of the sewage pipeline on a shale gas platform, and provides a reference for the corrosion prevention of the sewage pipeline.

To avoid cross-contamination between different samples, improve the cleaning effect of the outer wall of the inner needle of the digital PCR detector, and reduce the cost of cleaning solution, the cleaning jet was simulated by FLUENT software using VOF gas-liquid two-phase flow model and PISO algorithm. In a certain range, the inlet velocity, cleaning solution viscosity, interfacial tension, and contact angle are changed to simulate the theoretical cleaning of the outer wall of the injection probe and the selection of various parameters under the best cleaning conditions is determined. The results show that the increase of inlet velocity has no significant effect on the increase of wall static pressure and the decrease of velocity increases; the increase of viscosity will greatly reduce the flow rate; higher interfacial tension requires higher inlet velocity to form a continuous jet; increasing the contact angle will not significantly reduce the static pressure and flow rate, and the residual sample is easier to clean. When the inlet velocity of 200mm /s is selected, the fluorine oil with a viscosity of 0.00124Paꞏs and interfacial tension of 16.2dyn/cm is used and the wall is coated with Teflon, the cleaning effect, and economy are excellent.

Aiming at the current mainstream flying anchor payload for space debris removal, a solid thruster was proposed as the separation driving force, and a complete dynamic model of the spacecraft platform and payload were established. The effects of the gap between the directional button and the directional tube, thrust eccentricity and the initial attitude of the platform on the target accuracy under the flying anchor payload were studied. The analysis results showed that the initial attitude of the platform was the main factor affecting the target accuracy of the flying anchor payload. The control gap between 0.1mm ~ 0.25mm can effectively reduce the displacement of payload separation and the influence of disturbance on the platform.

An ultrathin Terahertz Triple-band ideal meta material absorber with a brand-new design that is straightforward has been presented. The suggested terahertz meta material absorber has a unit cell that is made up of two D-shaped resonators with slots and a ground metallic plane. These elements are separated from one another by a polyimide dielectric substrate that has a thickness of 500 micrometers. The absorber construction that has been presented provides three distinct absorption peaks within the narrow frequency range of (0.4-0.46 THz) without producing any interference. In order to get a deeper comprehension of the mechanism behind the absorption process, an investigation into the electric field, the magnetic field, the surface current distribution, and the independence of the polarization angle has been carried out. It is anticipated that the configuration of the terahertz absorber that has been described would find use in applications relating to the lowering of radar cross-section, detection, imaging, and sensing. One of the contributions of this study is the description of a downsized and compact triple-band terahertz meta material absorber. In order to generate the unit cell of a terahertz absorber, an identical I-typed resonator, which is represented by a rectangular patch with two very small notches, is first deposited on top of a dielectric sheet and then a metallic mirror. The terahertz regime reveals three distinct frequency spots, and the design of the very small structure allows for virtually full absorption of all of them.

In order to explore the engine surge when inlet distortion index and engine surge margin, the relationship between the parameter characteristics of research engine surge, strengthen safety monitoring assessment engine, this paper designed a kind of a certain type of engine bench test surge monitoring system, and unstable flow field of a certain type of vortex axis engine working parameters for monitoring and analysis. In this paper, a plug-plate distortion generator is used to induce a surge engine, and the circumferential static pressure changes of the inlet and outlet of the engine, the axial compressor and the centrifugal compressor under different working conditions are obtained. The changes of circumferential unevenness and mean turbulence, the pressure ratio at working point and the converted air flow rate at working point are analyzed with the increase of the height of the plug-plate under different working conditions. The results show that the distortion index of the working point increases and the surge margin decreases with the increase of the height of the plug-plate at the same rotating speed. When the height of the plug-plate is similar, the higher the speed is, the greater the distortion index of the working point is, and the smaller the surge margin is.

The research object was the wide-spread shunt extrusion production of large-diameter thick-walled AZ31 magnesium alloy pipe with 360mm outer diameter and 10mm wall thickness. Based on the DEFORM-3D finite element software platform, the simulation study on the influence of billet diameter on extrusion pressure was carried out to provide theoretical support for the reasonable selection of equipment tonnage. The results show that the peak extrusion pressure increases with the increase of billet diameter, and the increasing speed is accelerated. By reducing the billet diameter, the peak extrusion pressure can be gradually reduced from 4800 tons to 2200 tons, and the maximum extrusion cargo can be saved by more than 50%. If 3600 tons extruder is used, the billet diameter should be less than 325mm; If 2500 tons extruder is used, the billet diameter should be less than 285mm.

Energy storage is an effective measure to reduce the adverse impact of large-scale distributed photovoltaic access on the distribution network. Due to the high cost of the energy storage system, power grid planners urgently need to solve the problem of the optimal configuration of energy storage and photovoltaics. Therefore, this paper proposes a distributed energy storage planning and configuration method to promote the distributed photovoltaic consumption of the whole region. This method takes the maximum benefit of distributed photovoltaic energy distribution and storage as the objective function and takes power balance, charge-discharge power constraints, energy constraints, state of charge, and other constraints. Finally, a typical case of photovoltaic connection to an IEEE 33 node distribution network is selected to conduct a simulation analysis on the optimal configuration of different access locations for energy storage. The results show that after the energy storage system is connected, the node voltage offset of the distribution network is significantly improved, and the voltage quality is improved, which verifies the effectiveness of the capacity allocation method in this paper.

Aiming at the security risk of power system instability, this paper proposes a parameter optimization AVC planning strategy based on neural network. Based on a variety of power grid operation modes, the strategy innovatively uses genetic algorithm to improve the neural network quantile regression control variables to obtain state variables. This method can reduce the frequency of invalid operations, make the AVC control strategy more stable, and improve system security. In the actual case, the improved neural network quantile regression of genetic algorithm improves the accuracy by at least 29% compared with multiple linear regression.

Surface-enhanced Raman scattering (SERS), a simple, highly sensitive, and fast analytical method can be used to detect corrosion components on the surface of bronze ware, a difficult problem. The silver mirror reaction is suggested for depositing precious metal nanoparticles on cellulose filter paper in order to create a quick, easy, and low-cost approach for creating SERS substrates. After an 8-minute deposition time, optical microscopy and scanning electron microscopy (SEM) revealed a uniform dispersion of precious metals on cellulose filter paper. To examine the SERS characteristics of the substrate, copper chloride oxide, the main ingredient in the damaging rust of trace bronze ware, was used as the probe molecule. The findings show that cellulose filter paper with a uniform distribution of precious metals achieves the best SERS performance. The flexible substrate enables effective trace analysis of damaging rust on bronze surfaces.

With the development of marine transportation and underwater navigation technology, fluid drag reduction has become an international research hotspot as an important technical means to save energy and reduce environmental pollution. It has been found that the body surface structures of many organisms have unique drag-reduction properties. Therefore, it is feasible and important to replicate the morphological features of the body surface to the material surface. In this research, the structural features of biomimetic fish scales were summarized and extracted by observing the laminar arrangement features and morphology features of the surface scales of aquatic fish. Then, the arrangement features and morphology of fish-scales were abstracted into the oblique groove structure, and a three-dimensional model of the bionic fish-scale with a fan-shaped structure was constructed. The surface flow field of the bionic fish-scale was numerically simulated by COMSOL Multiphysics to revealing the mechanism of resistance reduction on the surface of the bionic fish-scale. The results indicate that the maximum drag reduction rate of the bionic fish scale surface is 8.40% compared with the smooth surface at a water speed of 0.6 m/s.

In this review paper, it is well established that high carbon high silicon steels on austempering result in carbide free bainite (CFB) which exhibits enhanced mechanical and tribological properties without adding any heavy alloying elements. Most of the research has been pointed out regarding the improvement of CFB steels that consists of the fine structure of bainitic ferrite laths and retained austenite (RA). In some cases, it was observed that the tensile strength of CFB steels was found similar to the commercial quenched and tempered steel alloys. Regarding other properties, it is estimated that out of the various failures that take place due to wear, 50% are caused by abrasive wear. To improve the lifetime of components, the selection of material and optimized processing techniques plays a pivotal role.

The paper aims at the problems of the high occupancy rate of communication resources and heavy server load caused by the image data taken during the inspection of the substation and sent to the remote server for processing. An edge intelligent inspection data processing architecture is constructed, and an insulator defect detection model based on transfer learning and YOLO v5 is proposed. The model can meet the training of a small sample network model in the case of scarcity of power equipment defect data. The proposed algorithm is compared with typical target detection algorithms, and the experimental results show that the proposed algorithm has an excellent performance in model recognition accuracy and recall rate. The trained insulator defect detection model is further deployed on the developed edge intelligent terminal for testing, and its image processing speed can meet the image processing requirements for intelligent inspection of substations. The system has good application value.

Diffraction-limited laser radiation with a record-high total average output power exceeding 14 W is obtained in the middle infrared spectral region through a new improved master oscillator – power amplifier system based on the strontium vapor laser. Precise microprocessing of optical grade fused quartz, sapphire, stainless steel, hard biological tissues, and polymers is also accomplished. Using a parabolic mirror for the laser beam focusing, spherical aberrations are overcome and a crater diameter and a channel width of the order of the laser wavelength are achieved.

In order to solve the problems of difficult measurement, inaccurate results and serious interference of diffusion and attenuation in the nondestructive evaluation of grain size of magnesium alloy components with complex profile, the sound field models of plane, cylindrical and conical parts based on the multiple Gaussian sound beam method are studied, and the attenuation mechanism of ultrasonic propagation in the medium of complex components and the diffusion and attenuation components in curved test blocks are analyzed, An evaluation method of ultrasonic attenuation of grain size based on diffusion loss correction is proposed to eliminate the influence of complex components on the total amount of ultrasonic attenuation. The results show that the ultrasonic nondestructive evaluation method of grain size based on sound velocity diffusion correction can effectively reduce the system error and improve the accuracy of grain size evaluation of magnesium alloy components with complex profile.

DC microgrid is the trend of the future distribution grid. Coordinated control of different types of distributed generation units, energy storage systems, converters, and loads in the DC microgrid to ensure efficient system operation is the focus of current research on the DC microgrid. In this paper, by taking the renovation project of Liangzi Island Electric Hotel in Hubei Province as a case, a coordinated control strategy based on DC bus voltage is proposed for internal power balance and stable system operation of the DC microgrid. Firstly, the operation mode is divided according to the different working conditions of the DC microgrid. The hierarchical droop control is used to associate each operating mode with different DC bus voltage intervals. Then a multi-source coordinated strategy is proposed, and each unit switches its operation mode according to DC bus voltage to maintain bus voltage and ensure power balance. Finally, the simulation is built and run in MATLAB/Simulink to verify the feasibility of the proposed coordinated control strategy.

Escalating the growth of industrialization and urbanization in the world demands the development of advanced infrastructure which in turn required a higher quality of raw materials. As cement is one of the major raw materials in concrete construction its demand for rising with the development of society. But the increased production of cement produces lots of environmental problems. So, there is a high requirement for a sustainable alternative of cement that have similar cementitious properties as cement. To address this problem experimental study is designed to use the binary blending of cement with rice husk ash (5%, 10%, 15% and 20%) as a replacement for cement. The study is further extended to analyse the effect of ternary blending of cement using further (5%, 10% and 15%) replacement of cement by sugarcane bagasse in optimum binary blended combination. Also, 25% of recycled fine aggregate is used in experiment as fine aggregate replacement throughout the mixes to achieve sustainability. Workability, compressive strength and flexural strength test were performed on concrete sample. The result of the study reveals that the workability of concrete mixes decreases with increases in the percentage of replacement both in binary and ternary mixes. In binary blending optimum strength is achieved at 15% replacement of cement with rice husk ash whereas in ternary blending 10% replacement by sugarcane bagasse ash with 15% rice hush ash was found optimum. Further, concrete shows 17.7% increase in compressive strength and 16% increase in flexural strength under the permissible value of workability. Study concluded that binary blending improve strength property and ternary blending further improve strength of concrete resulting in sustainability in construction.

This paper, aiming at the water-exit process of the vehicle with cavitation, based on the moving domain method coupled with the SDOF (six degrees of freedom) solver, using VOF (volume of fluid) multiphase model and the Schnerr-Sauer cavitation model, carrying out numerical simulation research on multi-conditions. Comparing vertical launch vehicles with different water-exit Ca (cavitation number) cases, the sudden decrease in cavitation number is closely related to the cavitation state, and there is a maximum influent cavitation state of the cavitation collapse on the process of the water-exit. Comparing different initial launch angle cases, it is found that there is a most unstable launch angle, which makes the angular deflection of the vehicle the most severe during the water-exit process.

The work is devoted to the creation of a laser method for monitoring the virucidal properties of nanocoatings of medical instruments. The relationship between the intensity of the spectra of washes from silver-doped coatings and the concentration of pathogens was studied. Plasmon resonance was obtained using a DFB laser in order to be able to develop this method.

We report on the stereolithography printing of a hydroxyapatite powder dispersed in an acrylate-based resin with a focus on the influence of the laser power, the scanning speed and the layer thickness on the dimensional accuracy of the green, debinded and sintered parts and on the microstructural and mechanical properties of the sintered parts.

With the scale of the power grid is becoming larger and larger. The corresponding operation and maintenance work of the distribution network is becoming increasingly intelligent, which also puts forward corresponding requirements for the reliability of safe and stable operation of the power grid. The condition assessment of relay protection applies the scientific concept of condition-based maintenance to the actual work site, which is of great significance. To judge the operation status of the equipment and provide a scientific basis for maintenance, in this paper, based on the application of digital twin technology in microgrid operation and maintenance, the method of calculating reliability probability density by function is applied to solve the problems of fuzziness, gray, and randomness of the relay protection status index. The invention can evaluate the state of the relay protection of the power system and can timely and accurately put forward the corresponding relay protection inspection and maintenance scheme, thereby improving the maintenance efficiency of the relay protection and further strengthening the power supply reliability of the power system. It can ensure the security and stability of the power system and reduce the reliable power consumption of the majority of power users.

With the promotion and popularization of national distributed photovoltaic projects, more and more residential users install distributed photovoltaic, which increases the income for residential users. However, for power companies, it is difficult to find out whether there are problems in the operation of photovoltaic equipment and whether users increase capacity privately during photovoltaic operation. Starting with the low-voltage distributed photovoltaic acquisition scheme, this paper establishes a low-voltage photovoltaic private capacity increase diagnosis model, so as to actively identify abnormal power generation and ensure the stability and safety of power grid operation.