In this study, a theoretical prediction model of mixed molten salt electrical conductivity was proposed based on the theory of heat generation by ion friction under an AC electric field, and a set of molten salt electrical conductivity measurement devices was designed to analyze the electrical conductivity of Solar salt, Hitec salt and Hitec XL salt. The results show that the mean absolute percentage error （MAPE） values between the theoretically predicted values and experimentally measured values of electrically conductivity for three types of mixed molten salts are 11.646%, 5.473%, and 3.419%, respectively. The trends of theoretical predicted values and experimental measured values are consistent, confirming the accuracy of the proposed theoretical prediction model.

Based on the relevant accounting methods of life cycle assessment and the Intergovernmental Panel on Climate Change （IPCC） National Greenhouse Gas Inventory Guidelines, the carbon emission reduction benefits and potential of biomass gasification power generation with CO₂ capture-soda production technology were evaluated. The results show that biomass gasification power generation with CO₂ capture-soda production technology using corn stover as raw material has significant carbon reduction benefits, with a reduction of 3.88 t/（t-straw） or 6.45t/（MW·h）. The contributions of CO₂ capture-soda production and power generation to carbon reduction benefits are 84.27% and 15.69%, respectively. Collaborative optimization of transportation and power generation systems can achieve a maximum carbon reduction of 4.32 t/（t-straw）, showing great carbon reduction potential. Compared with similar technologies from the perspective of product output or biomass waste reduction, biomass gasification power generation with CO₂ capture-soda production technology has strong carbon reduction benefits.

This study evaluates the accuracy of three widely used solar radiation datasets（NASA, Solargis, and Meteonorm）for solar resource assessment in China. The evaluation is conducted by comparing their monthly global horizontal irradiance （GHI） estimates against high-quality ground-based measurements from 99 meteorological stations across China. A comprehensive index-based evaluation framework was established to identify the optimal datasets for each region and derive corresponding error correction coefficients. The results show that the spatial distributions of GHI from Solargis and Meteonorm align more closely with observations than those from NASA. The most significant discrepancies are observed in Northwest China, Xizang and Sichuan Province. Error analysis indicates that Meteonorm achieves the highest correlation coefficient （R） （R ≥ 0.98 at 75% of the stations） and the smallest error accounting for all error metrics, including root mean square error, mean absolute error, and mean relative error. Solargis demonstrates moderate accuracy, while NASA exhibits the largest error. A significant correlation is identified between latitude and mean relative error. Solargis tends to overestimate GHI at lower-latitude and underestimate at higher latitudes, whereas Meteonorm displays the opposite trend. Based on the results of error analysis, this study constructs a comprehensive index evaluation method, screens out the optimal data types of 99 stations, and spatially interpolates them to the national scale. The findings suggest that Meteonorm is preferred in 55% of China’s regions, followed by Solargis in 27% and NASA in 18%. The mean relative error of the optimized dataset is confined to a range of -4.5% to 5.9%. To improve the accuracy of solar energy assessments, the following calibration is recommended: GHI values should be increased by 1%-5% in northern regions, Xizang, and western Sichuan, and decreased by 1%-6% in southern Xinjiang, Qinghai, Central China, and South China.

In this review, the preparation strategy and synthetic methods of Fe-N-C catalysts in recent years including template method, impregnation method and in situ capture method etc are systematicauy summarized. The current developments of pyrolytic Fe-N-C catalysts derived from metal-organic frameworks, organic porous polymers and biomass are emphatically outlined. The structure of active sites and reaction mechanism in Fe-N-C catalysts are also discussed. Then, the challenges and future development directions of Fe-N-C catalysts for ORR are discussed and summarized.

Sodium acetate trihydrate （SAT） has been identified as a potential energy storage material in the field of solar thermal collectors because of its advantageous latent heat of phase transition and suitable phase transition temperature. However, SAT is subject to defects such as subcooling and phase separation during the phase transition. In the present study, a range of thickeners and nano-nucleating agents were utilised in the modification of SAT, with the objective of producing composite SAT with optimal performance. It was observed that the composite SAT not only ameliorated the inherent limitations of SAT, but also exhibited favourable thermal properties. The study proceeded to explore the mechanism of phase separation and subcooling of SAT, and the associated solutions. A comparative analysis was conducted on the inhibition of phase separation and subcooling of SAT with thickening and nucleating agents. Finally, the potential applications of the composite SAT in solar energy post-modification were examined. Following the modification of composite SAT, the subsequent direction of application in the field of solar energy is discussed.

Researches on enhancing the evaporation performance of solar interfacial evaporators are reviewed with evaporation rate and evaporation efficiency as two evaluation indicators. Six methods, including light absorption enhancement, thermal management, water transport control, evaporation enthalpy reduction, other energy utilization, and salt resistance strategies, are summarized. The principles and main means of each method are outlined. Finally, the current urgent problems that need to be solved in solar interface evaporation technology are given for future research directions.

Considering the effects of dynamic rotational speed and meshing load of the planet gear during start-up, a 5-degree-of-freedom frictional dynamics model of coupled journal and bidirectional thrust bearings is established to investigate the lubrication performance during the start-up phase. The equivalent boundary conditions for the planet gear during start-up are derived from a multi-body dynamics model of the wind turbine gearbox. The impacts of pressure coupling boundaries, thrust bearings, and axial clearance on the lubrication performance of the coupled bearings are analyzed and validated through experiments. The results indicate that, under the influence of dynamic meshing load from the planet gear, the journal bearing experiences slight asperity contact at the conclusion of the start-up phase, with film pressure alternating between single and double peaks. The maximum film pressure is enhanced by the pressure coupling boundary. The bidirectional thrust bearing can mitigate misalignment and eccentricity in the load direction, while potentially increasing them in the non-load direction. Insufficient axial clearance can lead to a significant increase in maximum film pressure and fluctuation of the thrust bearing, as well as a reduction in the load balancing performance of the thrust pads.

Focusing on the digital trarsformation of wind tunnel tests, in response to the demand for the integration of physical wind tunnel tests and computational fluid dynamics（CFD） numerical tests, this study designed and developed a digital wind tunnel system based on the NF-3 airfoil wind tunnel at Northwestern Polytechnical University（NWPU）. The system replicates the experimental NF-3 wind tunnel model, simulates the control process of experimental wind speed, and enables automated execution of experiments in a virtual wind tunnel. To achieve automation and operational deployment, the digital wind tunnel system uses customized grid templates for the automatic generation of both background and model grids. These grids are assembled using overset grid technology, and low-speed precondition techniques are employed to accelerate the convergence of the compressible flow solver. This paper firstly introduces the basic component sections and the control strategy of the physical wind tunnel. Subsequently, it elaborates on the design of the digital wind tunnel system, including the automatic generation of airfoil grid, automated assembly of wind tunnel and airfoil grids, flow solver methodologies, and virtual control strategies for digital wind tunnel. Finally, this research conducts a virtual experiment in the digital wind tunnel utilizing the standard wind turbine air-foil DU91-W2-250, and compared with traditional CFD simulated results. The results demonstrate that the system can effectively support digital wind tunnel experiments, capturing spanwise separated flow region variations that are absent in conventional quasi-2D simulations and the results align better with physical experiments.

This study introduces a novel hybrid forecasting model, which uniquely employs the sparrow search algorithm to optimize the parameters of variational model Decomposition. Subsequently, the model utilizes variational mode decomposition and complete ensemble empirical mode decomposition with adaptive noise for dual rounds of time series decomposition related to solar power, followed by the application of convolutional neural networks and long short-term memory with attention mechanisms to train and forecast the decomposed series data. The proposed model undergoes validation using real-world data across various weather conditions and resolutions. The results consistently demonstrate the superior predictive performance of the new method across different time resolutions （2 or 10 minutes）, forecast ranges （1, 3, or 5 days）, and diverse weather conditions, with a remarkable correlation coefficient of the predicted values exceeding 0.97.

In order to reveal the wind field characteristics of downburst flow at different jet inclination angles and their effects on wind turbine blade deformation, this study simulated the wind field characteristics of atmospheric boundary layer at five jet inclination angles of 0°, 5°, 10°, 15° and 20° based on computational fluid dynamics method, analyzed the horizontal and vertical wind velocity profiles of downburst flow at different jet inclination angles. Meanwhile, the influence of wind field with different jet inclination angles on blade surface pressure distribution and structural deformation is explored. The results show that with the increase of jet inclination, the maximum horizontal wind speed on the side where the downburst occurs increases, and the rate of vertical velocity decreasing slows down. The change of inclination angle has anegligible effect on the pressure in the area where the downburst occurs. For the influence of turbulence intensity distribution, the turbulence intensity at the back of the jet region increases with the increase of jet inclination, while the turbulence intensity at the front side decreases. When the wind turbine is located in the downburst flow field with different jet inclination angles, the distribution of blade surface pressure is inhomogeneous, and the blade tip bears more wind pressure than other positions. With the increase of jet inclination angle, the blade surface pressure increases, the pressure of the near-ground two blades increases substantially, reaching the maximum value of about 50 Pa when the inclination is 20°. The pressure of the father-from-ground blade surface increases slowly. The structural deformation at blade tip and the equivalent stress in the middle of blade increase with the increase of the inclination angle. This study provides some theoretical support for the safe operation of wind turbines in extreme weather, also offers assistance for wind turbine anti-wind design.

The settlement-adjustable wind turbine foundation is a new form of active settlement-regulated wind turbine foundation suitable for deep dump ground layer. The model test method was used to investigate the differences in the force response and deformation patterns of the various components of the traditional gravity wind turbine foundation and the settlement-adjustable wind turbine foundation during operation under horizontal cyclic loading. The test results show that： under horizontal monotonic loading conditions, the ultimate bearing capacity of the settlement-adjustable foundation is better than that of the traditional gravity foundation, with an increase of about 160%; under horizontal equal-amplitude short-term cyclic loading conditions, the amount of change in the inclination of the foundation of the same foundation form and the size of the amplitude of the cycle load are positively correlated, and the amount of change in the inclination of the settlement-adjustable foundation of the same amplitude of the load is obviously smaller than that of the gravity foundation; under horizontal variable-amplitude long-term cyclic loading conditions, the amount of change in the inclination of the settlement-adjustable foundation is significantly smaller than that of the gravity foundation. Under the condition of horizontal amplitude long-term cyclic loading, the amount of change of inclination, displacement and soil pressure of settlement-adjustable wind turbine foundation keeps obviously smaller than that of gravity-type foundation. The axial force of settlement-adjustable wind turbine foundation keeps increasing during the loading process, but the growth rate is gradually slowing down, and the increment of axial force decreases with the increase of monitoring depth of the pile body.

This paper introduces the principle and application of anti-reflection and self-cleaning thin films. By adjusting the refractive index, thickness and number of layers the thin films, the light reflection loss can be effectively reduced, and the transmittance can be enhanced, so as to improve the power conversion efficiency. The advantages and disadvantages of single-layer, double-layer and multilayer anti-reflection thin films are also discussed. By adding the function of self-cleaning on the basis of anti-reaction coatings, as well as surface modification and decorating photocatalytic materials, the hydrophilic or hydrophobic functionalization can be achieved. Finally, the future development prospect of anti-reflective self-cleaning thin films is discussed.

A load reduction method was provided by optimizing the aerodynamic configuration and structural design of the blades in this paper. The GH-Bladed computing platform was used to verify the blade performance and turbine load based on 6.25 MW wind turbine. The study finds that reducing the blade chord length has the most significant effect on reducing the blade root load, while the effect of reducing thickness on load reduction is not prominent. However, reducing blade thickness is a convenient method to improve aerodynamic performance while also weakening load. In addition, the laying thickness of the spar cap structure can change the blade flapwise stiffness to affect flapwise deformation. Expanding the blade flapwise deformation by adjusting the thickness of the blade spar cap to release concentrated stress is a novel method to promote the reduction of blade load generation.

Aiming at the problem of detecting bird droppings and shading defects as well as light spot defects formed by diode damage in photovoltaic modules under aerial high-resolution images, a detection algorithm combining the improves deep learning model YOLOv8n with slice-assisted super-reasoning is proposed. The PV module dataset is constructed by slicing 2667 visible and thermal imaging images and labelling them with three kinds of defects： bird droppings, shading and light spots. Firstly, on the backbone network of YOLOv8n, a small target detection layer is constructed by adding a 3-layer CBS module to enhance the transmission of small target feature information. Secondly, a global attention mechanism is added to the Backbone part, adopting the framework of channel and spatial attention, so that the model can better capture the global feature information. Based on the above two improvements to the network structure to design its ablation experiments, the experimental results show that the improved model improves the mAP50 value and mAP50：95 by 4.3% and 1.5%, respectively, compared with the base model; to design the comparison experiments between the improved model and the other target detection models, and the experimental results show that the improved model's accuracy is better than that of the other detection models. Finally, combined with slice-assisted hyper-reasoning for slicing before detection, the overall model comparison experiments are designed with the addition of slice-assisted hyper-reasoning, and the experimental results show that the improved YOLOv8-PG+SAHI model is optimal for detecting small target defects in high-resolution photovoltaic module images, and the accuracy rate can reach 88.73%. The above experiments show that the improved model is more suitable for small target detection of PV modules under aerial high-resolution images.

Based on the practical needs of offshore photovoltaic systems, various floating wave-dissipation structures were designed and tested in a two-dimensional large-scale wave tank under irregular wave conditions. Time-domain response signals were measured, and the wave transmission coefficient, reflection coefficient, and wave energy dissipation coefficient were analyzed. The study demonstrates that compared to single-floating-box breakwater, increasing the width of a single floating box, adding additional floating boxes, and incorporating vertical insert plates or wing plates on the bottom can significantly enhance wave energy dissipation and improve wave attenuation. For the designed double-floating-boxes structure, each 0.5 m increase in the slanted wing depth reduces the transmission coefficient by an average of 15%. Additionally, installing a porous plate between the pontoons further reduces the transmission coefficient. Under irregular waves with an effective wave height of 2 m, the wave energy transmitted through the dual-pontoon floating breakwater with wing plates and porous insert plates is only 12% left, meeting the wave attenuation requirements for offshore floating photovoltaic power stations.

This paper takes the IEA 15 MW wind turbine blade as the research object, establishes the dynamic model of the aeroelastic system for the blades, analyzes the aeroelastic response during flutter at high tip speed ratio, and conducts in-depth research on the multi-degree-of-freedom coupling characteristics therein. The results show that at high tip speed ratio, the long and flexible blade of this wind turbine undergoes a coupled bending-torsion flutter of pitch-torsion. The vibrations in the three degrees of freedom all contain the natural frequencies of pitch and torsion. However, the maintenance of flutter is sustained by the aerodynamic power work in the pitch and torsion degrees of freedom. There is an obvious coupling phenomenon in the development of the instantaneous aerodynamic power of pitch and torsion. In the direction of yaw, there is basically no energy contribution. There is only weak aerodynamic power throughout the process, and it only undergoes forced vibrations due to the excitation of pitch and torsion because of the coupling characteristics of the blade structure.

To address the issues of low voltage gain and high voltage stress existing in traditional quasi-Z-source DC-DC converters, a high-gain soft-switching quasi-Z-source DC-DC converter （HGSS-QZS） is proposed. By adjusting both the turns ratio of the three-winding coupled inductor and the duty cycle of the switch, the boost capability and the flexibility of gain adjustment are improved. A clamping circuit is employed to absorb the leakage energy of the coupled inductor, reducing the voltage spikes caused by leakage inductance. Firstly, the operating principle of the HGSS-QZS converter is analyzed in detail, and voltage gain, device voltage and current stress, and efficiency losses are derived. Next, parameter design is carried out and compared with existing converters, demonstrating that the HGSS-QZS converter offers high voltage gain, low voltage stress on components, soft-switching capability, and high efficiency. Finally, a 200 W experimental prototype was built, and the validity and feasibility of the HGSS-QZS converter were verified through simulation and experimental comparison.

The new power system in agricultural parks faced the problems of poor system operation stability and low comprehensive economic efficiency due to power fluctuation on the generation side and diverse and uncertain load demand on the consumption side. For this reason, this paper constructed a model of optimized allocation of energy storage capacity based on load division, aiming to improve the stability and economic efficiency of the system. Firstly, a two-stage energy storage allocation tactic was determined in accordance with load segmentation. In this regard, the conventional load demand was preferentially supplemented by photovoltaic power, and the root-mean-square （RMS） envelope technique was harnessed to quell the unsteady power oscillations. Secondly, for the agricultural load demand, the net present value （NPV） was constructed as the optimization objective function. This was then conjoined with the time-of-use tariff strategy to impel the energy storage capacity to perform peak shaving, valley filling, and consumption compensation. Finally, by leveraging the summer and winter data of an agricultural park and deploying the particle swarm optimization algorithm, the outcomes of the two-stage allocation were attained. Namely, the overall power oscillations of the summer and winter loads are abated by around 32% and 27% respectively. The peak-to-valley ratios of the loads are lessened by 13.1% and 14.4% respectively. Moreover, the comprehensive economic return of energy storage is enhanced by 21% when compared with the direct allocation method. The exemplifications corroborated that the methodology proposed in this paper could efficaciously attenuate the microgrid power fluctuation quandary and augment the comprehensive economic benefits engendered by energy storage allocation.

This study explores the distinct forms in which water molecules exist within hydrogel structures and discusses the design of solar evaporators that enhance water evaporation efficiency by modifying the surface morphology of hydrogels. Finally, the research progress on solar evaporators that combine various photothermal media with hydrogels is systematically reviewed, and prospects for their future development are discussed.

A new solid oxide fuel cell-gas turbine-Kalina cycle （SOFC-GT-KC） hybrid power system integrated with high-temperature solar therm chemical and methane complementary is proposed in this article, which uses high-temperature solar energy to drive methane reforming to produce hydrogen, and the produced hydrogen-rich syngas drives the SOFC-GT-KC hybrid power system to generate electricity, realizing efficient energy cascade utilization. The analysis model of the new system technical and economic performance is established, with simple payback period, dynamic payback period, net present value, and levelized cost of electricity as performance evaluation indicators. The effects of fuel price, electricity sale price, annual operating hours, interest rate and discount rate on the new system’s techno-economic performance under the given operation strategy are analyzed, and the economic performance of the new system performance in different regions with different operating conditions is studied. The research results show that the total cost of the new system within the design life is 19.23 million yuan, of which fuel cost accounts for the highest proportion, reaching 58.57%. The net present value of the new system at the end of its design life is 1.31 million yuan, with a simple payback period of 11.06 years. The calculation results of typical regional applications show that the net present value of the new system is higher and the investment payback period is shorter in areas with strong solar radiation and high electricity price, while the average levelized cost of electricity is lower in areas with low gas prices and strong solar radiation.

Physical model tests were conducted in sandy soil to study the response characteristics of tripod bucket jacket foundations under cyclic loading. The cyclic rotation angle response, natural frequency, and damping ratio of the structure were analyzed. Based on the test results, an empirical prediction formula for the cumulative rotation angle of the foundation was proposed. The results indicate that an increase in cyclic load amplitude accelerates the accumulation rate of the foundation’s rotation angle. In a log-log coordinate system, the cumulative rotation angle of the foundation and the number of load cycles approximately exhibit a linear relationship. The natural frequency of the structure demonstrates a similar pattern of change under different cyclic load amplitudes： initially, there is a slight increase in the natural frequency, followed by a sharp decrease, and it then fluctuates around a certain average value as cyclic loading continues. The system's damping ratio sharply decreases at the beginning of loading, reducing to about 20% of the initial value, and then undergoes significant oscillations, with a variation of up to 80%.

In this study, the effects of pyrolysis temperature and lignocellulosic biomass/microalgae blending ratios on the yield, elemental composition, surface morphology, thermal stability, pore structure, surface functional group distribution and carbon skeleton structure of biochar derived from lignocellulosic biomass and microalgae co-pyrolysis were systematically investigated, and the synergistic effect and reaction mechanism during the co-pyrolysis process were further revealed. The results show that pyrolysis temperature and biomass/microalgae blending ratios had significant influence on the yield and physicochemical structure of co-pyrolysis biochar. The biochar yield decreases with rising pyrolysis temperature, and increases with higher microalgae blending ratios. The yield of co-pyrolysis biochar can reach as high as 41.51%, which is 23.5% higher than that of individual biomass biochar. The co-pyrolysis process of microalgae and lignocellulosic biomass exhibits a significant synergistic effect, which can enhance the yield of biochar and significantly promote the enrichment of C and N elements in biochar. The increase of pyrolysis temperature facilitates the conversion of pyridine-N to quaternary-N in biochar. With the increase of the microalgae blending ratios, the disorder degree and aromaticity of biochar is enhanced. The nitrogen-containing volatile produced from microalgae can react with the oxygen-containing functional groups on biomass through Maillard reaction, which further experience cyclization reactions and polycondensation reactions to form nitrogen-rich biochar.

To enhance the prediction accuracy of waves in multi-island sea regions, this study uses the measured wave data of 57 typhoons in the Yangtze River Estuary and the coastal waters of Zhejiang Province from 1987 to 2022 to investigate the attenuation coefficients of wave height in various sea areas through data processing and analysis. The leef-sheltering coefficients is employed to quantify the influence of reef location, size and other factors on the average periods of mixed waves. Based on the measured wave height-period relationship of mixed waves, a method for determining the maximum and minimum periods of mixed waves is proposed. Finally, the friction coefficient of the wave bottom in the study area is calculated by using theoretical formulas. As shown in the results, the wave height gradually diminishes during the wave propagation towards the inshore, and the wave energy attenuates more rapidly in the areas with numerous islands than in open areas without islands. In a multi-island sea area, the period of mixed waves will gradually decrease under the effect of reef shielding, while the degree of period reduction increases with the increase of the reef shielding degree. For a certain wave height, the wave-period relationship of the strong wave direction at offshore stations can be regarded as the maximum possible period of the mixed wave, while the wave-period relationship of the wind waves can be taken as the minimum possible period of the mixed wave. As demonstrated in the calculation, in the Yangtze River Estuary and the near-shore regions of Zhejiang Province, the wave bottom friction coefficient Cb is 0.050 m²/s³, and the bottom friction coefficient f is 0.009.

In this paper, MCM-41 mesoporous molecular sieve catalysts modified by Cu, Fe, Co and Ni elements were prepared by impregnation method. XRD and BET characterization analyses were carried out on the modified catalysts to explore the physicochemical structures and other characteristics of catalysts modified by different metals.The effects of co-pyrolysis of cellulose, lignin and polypropylene （PP） on the synergistic reaction and the distribution of pyrolysis products were investigated by TG-FTIR and Py-GC/MS. The results show that MCM-41 can promote the reaction between biomass and PP, and the yields of aromatics and light hydrocarbons are increased. Compared with MCM-41, modified MCM-41 can promote the precipitation of light olefins, C₅~C₁₁ aliphatic hydrocarbons and aromatics. Cu, Fe and Co modification can promote the formation of monocyclic aromatics. Compared with MCM-41, MP-M/Fe has the highest proportion of olefin precipitation, reaching 59.68%, and XP-M/Fe has the highest proportion of light olefin precipitation, reaching 32.84%. XP-M/Co has the highest proportion of alkane precipitation, reaching 34.22%. The proportion of other groups of alkenes and alkanes in the pyrolysis products increases.

To achieve efficient and low-carbon hydrogen generation, a zero carbon emission hydrogen production system combining methane and solar energy is proposed. The system decouples one-stage methane reforming into two-stage methane reforming： a portion of high-temperature flue gas is introduced into the pre-reforming reactor as reactants, and the reaction heat is provided by solar energy; The reaction heat during the reforming process is providedby combusting purge gas with oxygen from the electrolytic cell. Another part of the flue gas is directly condensed and separated carbon dioxide after preheating the water to be electrolyzed. Energy and exergy balance analyses are conducted on the proposed and reference systems. The results demonstrate that the energy and exergy efficiencies of the proposed system are improved to 42.88% and 39.21%, respectively, by 4.77 and 4.53 percentage points compared to the reference system. Using the exergy utilization diagram （EUD） reveals the main reasons for improved system performance. Comprehensive utilization of solar energy through thermochemistry and electrochemistry. This not only increases the efficiency of solar energy utilization, but also eliminates high-energy consumption carbon dioxide separation devices, resulting in a total increase of 4.23 percentage points in exergy efficiency. The two-stage methane with flue gas reforming process reduces the exergy destruction of high-grade methane chemical energy into low-grade thermal energy during combustion, as well as the heat loss in the heat exchange process, resulting in a total increase of 2.02 percentage points in exergy efficiency.

Response surface methodology was used to analyze the effects of molding temperature, pressure, proportion of binder and mixing ratio of raw materials on the density of seedling bowl, breakage by dropping, and breakage by pressure. Then the process parameters were optimized by applying the satisfaction function method and multi-population genetic algorithm. In addition, the effect of seedling bowls on the physicochemical properties of soil was also analyzed. The results showed that the density, drop breakage rate and compressive breakage rate of seedling bowls reached 0.908 g/cm³, 2.98% and 2.68%, with the temperature of 60-110 ℃, pressure of 8-18 MPa, binder to raw material mass ratio of 0.6∶1-1.3∶1, and the corn stover charcoal content of 10%-60%. The optimal combinations of process parameters were temperature 67 ℃, pressure 13.64 MPa, binder to raw material mass ratio 0.78∶1, and corn stover charcoal to Sophora japonica raw material mass ratio 3∶7, under which the density, drop breakage rate and compressive breakage rate of seedling bowls were 1.032 g/cm³, 2.65% and 2.34%, which were only 0.02%, 0.01%, and 0.03% from the predicted values. After the seedling bowls were buried in the soil for 8 weeks, the soil pH value decreased from 8.92 to 8.02, and the soil quick-acting nitrogen, quick-acting phosphorus, and quick-acting potassium increased by 57.1, 27.0, and 38.0 mg/kg respectively, which indicated that the corn stover charcoal-mixed Sophora japonica biomass seedling bowl could effectively reduce the soil pH value and improve the soil fertility.

Considering the demands of clean and efficient heating with grid peak shaving and valley filling, a novel building heating system combined with photovoltaic/thermal, heat pump and heat storage using off-peak electricity （PV/T-HP-VEHSH） was proposed. The optimization design method for PV/T-HP-VEHSH was developed targeting optimal heating reliability, minimal carbon emissions and initial investment based on the pattern search algorithm. The operating performance of PV/T-HP-VEHSH was studied by TRNSYS software and the performance improvement was also investigated in comparison with the photovoltaic-air source heat pump heating system and the heating system without thermal storage by off-peak electricity. The results show that the PV/T-HP-VEHSH has the optimal comprehensive benefits at the ratio of flow rate of the thermal collection water pump to PV/T area of 13.8 （kg/h）/m², the ratio of volume of thermal collecting tank to PV/T area of 0.1 m³/m², and the ratio of electric boiler capacity to volume of thermal storage tank of 1.2 kW/m³. The average monthly COP of PV/T-HP-VEHSH varies from 2.8 to 3.2 and the comprehensive photoelectric and photothermal efficiencies of PV/T are higher than 56% during the heating season in cold zones. The operation cost of PV/T-HP-VEHSH is reduced by 3.3 ¥/m² due to the thermal storage using off-peak electricity.

To alleviate the limitation on distributed photovoltaic integration imposed by the inflexibility of the spatiotemporal distribution of new energy and load, this paper proposes a co-planning strategy for energy storage and intelligent soft-switching to enhance the capability of power distribution networks for distributed PV power. Firstly, to evaluate the collaborative benefits of multi-port soft open point （MSOP） and energy storage system （ESS） in spatiotemporal flexibility, an evaluation metric integrating branch current time-uniformity level and network loss sensitivity is proposed. Subsequently, a two-level stochastic optimization model comprising planning and operation is established based on this collaborative benefit metric. By embedding the MSOP-ES model, this framework is capable of considering diverse integration forms of MSOP and ESS. Finally, the two-level optimization model is efficiently solved using the Benders decomposition algorithm. Case studies on the IEEE 33-node distribution network and a real-world distribution network demonstrate that the proposed method effectively enhances PV hosting capacity while improving voltage stability and flexible transfer capability by planning ESS and MSOP integration.

To solve the problem that PV power fluctuates significantly and is difficult to predict, this paper proposes a combined PV power prediction model based on similar day clustering and an WOA-WMD-TCN-Transformer model. Firstly, K-means ++ is used to cluster similar days. Then WOA was used to optimize VMD parameters, and the PV power sequence was decomposed into multiple Intrinsic Mode functions（IMFs）. The IMF components and meteorological factors were weighted and combined into a new feature vector and fed into the subsequent model. Based on TCN-Transformer, IMF under different weather conditions can be predicted separately and the predicted value can be obtained after superposition. Finally, the photovoltaic power generation and meteorological data of Hanwha Solar Photovoltaic Station, a desert solar Research Center in Alice Springs, Central Australia, were used as an example to verify the validity of the model. Ablation experiments and comprehensive evaluation show that the proposed model can achieve high prediction accuracy under various weather conditions.

This paper proposes a fuel cell aging trend prediction method based on the PatchTST model. By segmenting time series data into multiple local time windows and combining the Transformer architecture to capture long-and short-term dependencies, the method achieves precise prediction of fuel cell aging trends. In the experiments, the model was trained under steady-state and quasi-dynamic operating conditions using data with training set proportions of 50%, 60%, and 70%, respectively, to predict aging trends for future horizons of 50 h, 100 h, and 150 h. Analysis based on error evaluation metrics, such as URMSE and UMAE, indicates that the model achieves the lowest prediction error when the training set proportion is 60% for the FC1 dataset and 50% for the FC2 dataset. Although the error increases slightly as the prediction horizon extends, the overall performance remains relatively stable. Under the conditions where the FC1 dataset is divided by 50% and 60% ratios, the prediction errors of the PatchTST model are lower than those of the Informer, Transformer, GRU, and LSTM models.

This paper proposes an improved centralized damping method： applying a damping matrix at the equivalent rotational center of the monopile. The equivalent rotational center serves as a "decoupling point" for the monopile foundation, addressing the coupling issue in the stiffness matrix at the mudline that complicates rotational damping coefficient calculations based on apparent rotational stiffness. First, the formulas for calculating the damping ratio of the pile-soil interaction system and the position of the equivalent rotational center are derived. Then, this improved method is incorporated into the integrated time-domain analysis of offshore wind turbines by developing the SoilDyn module in OpenFAST. Finally, the validity of the improved centralized damping method is verified by comparing it with distributed damping results under the same load conditions.

As the basis of transformer range lean management, the precision of distribution （for short of 400V distribution） user-branch-distribution transformer topology draws more attention. Based on the characteristics of distribution tree topology, the principles and defects of current distribution topology identification methods were analyzed with the correlation among electrical parameters. A novel distribution topology identification method based on time-frequency domain data fusion was proposed, which consists of two links： 1） Forward link. Spectrum clustering algorithm was modified to cluster node voltages including fundamental and harmonic domains level by level.Furthermore, in order to calculate the node voltage vector corresponding to the upper level topology branches, a Confined-field Neural Network was devised, which is able to discriminate the topology type （radiation or trunk） via cluster node transformation group features. 2） Backward link. In the solution space compressed by the forward link, the active power balance principle was utilized to check and correct the suspicious nodes. Such closed loop identification framework possesses promoted result precision and sophisticated topology applicability. Finally,3 residential/commercial and industrial pilot transformer range with typical topology in State Grid Zhejiang Company were selected as examples. The proposed method was paralleled with several current distribution topology identification methods, with its advantages verified.

To address frequency drops in the power system during various frequency support intervals, this paper proposes a method for setting frequency support control parameters for wind power based on weighing frequency extreme points. First, we qualitatively analyze how frequency support control parameters of wind power impact the system’s dynamic frequency response. Next, we derive the time-domain expression for the system frequency dynamic response model, taking into account the contributions of synchronous generators and wind power during frequency support. We also investigate how different damping ratios affect the accuracy of the time-domain analytical formula. Subsequently, we analyze the power disturbances experienced by the system when wind turbines exit frequency support, developing a calculation method to evaluate the system’s frequency extreme points during the rotational speed recovery period of wind turbines. Based on this analysis, we establish an optimization model aimed at setting frequency support control parameters that minimize all frequency extreme points during the frequency support intervals. Finally, case studies validate that the proposed method can effectively set frequency support parameters according to varying wind power proportions, ensuring the frequency support capability of wind turbines without causing significant secondary frequency drop in the system due to excessive release of kinetic energy during frequency support.

Deep-sea wind energy development represents a strategic high ground in renewable energy and an inevitable solution to overcoming near-shore resource constraints. However, harsh marine environments lead to significantly increasing difficulty and costs in wind turbine operation and maintenance （O&M）. Recent advancements in digital technologies such as artificial intelligence, big data, and digital twins have created new opportunities for intelligent and automated O&M of offshore wind turbines. This paper first examines current development trends in offshore wind turbines： large capacity and commercialization, deep-sea and floating, intelligence and automation. Subsequently, it systematically reviews data acquisition methodologies and equipment for offshore wind turbines detection and monitoring, along with advanced data analysis techniques. The state-of-the-art applications of digital technologies in maintaining critical components of offshore wind turbines are comprehensively summarized. Finally, future research priorities for intelligent O&M of floating offshore wind turbines are prospected.

The structural dynamic characteristics of offshore wind turbines are directly related to the operational safety and equipment reliability of in-service wind turbines, but because of the complex working environment, a single load analysis cannot reflect the structural dynamic characteristics of its actual operating state. In this paper, considering the distinctive configuration attributes of 5-megawatt marine wind energy generators, Kaimal wind speed spectrum is used to establish a three-dimensional model of Marine turbulent flow field, and Kärnä ice force spectrum is combined to build a floating ice mathematical model, and the working conditions of the actual operating environment of offshore wind turbines are reproduced through the arrangement and combination of multiple working conditions. Combined with OpenFAST and EDEM discrete element analysis method, the dynamic response characteristics of wind turbines under wind, wave and ice loads are studied. The results show that the transverse and longitudinal dispositions of the tower top and the transverse and longitudinal bending moments of the tower are greater than that of the single load, but the cumulative fatigue damage caused by the coupling load is smaller than that of the single load.

To achieve a simple and low-cost real-time measurement of sea waves, this article proposes a non-contact wave parameter measurement method based on shape-from-shading （SFS）. Initially, a single camera is used to capture images of the wave tank and floating reference objects. Then, the three-dimensional shapes of the wave surface and reference objects are reconstructed using the SFS method. A size transformation coefficient is introduced into the 3D reconstruction results to accurately calculate wave parameters. The proposed method's wave parameter measurements are compared with actual measurements. Results indicate that the relative errors for average wave height and wavelength are less than 5%, the relative error for the average period is less than 1%, and the deviation in wave direction is within 5°. This method demonstrates high stability and accuracy.

This paper proposes a distributed voltage control algorithm for distribution networks based on an improved model-free adaptive control method. The proposed algorithm leverages real-time sampling data from distributed PV units and estimates the dynamic linearization parameters that characterize the voltage control characteristics of the distribution network online through adjacent communication between the PV units. This data-driven, iterative approach achieves coordinated reactive power-voltage control without relying on a detailed network model. The stability of the algorithm is proven mathematically. Finally, a multi-scenario simulation is conducted using the modified IEEE 33-bus distribution system to demonstrate the effectiveness and advantages of the proposed control algorithm.

In order to assess environmental impact throughout the full life cycle of the monocrystalline silicon photovoltaic system, a life cycle assessment （LCA） method was used to analyze and evaluate the energy consumption and carbon emissions of the production, transportation, operation and recycling stages of the 1 kW monocrystalline silicon photovoltaic system. The results show that the whole life cycle energy consumption of the 1 kW monocrystalline silicon photovoltaic system installed in Kunming is 992.08 kWh, with carbon emissions of 2033.24 kg. The energy payback period and carbon payback period are 0.90 and 16.96 years, respectively, both of which are shorter than the system’s operational lifespan. Energy consumption and carbon emissions are primarily concentrated in the production stage, with the production of solar-grade polysilicon having the largest share, followed by the production of balance-of-system components and monocrystalline silicon wafers. Improving the production technologies for solar-grade polysilicon, balance-of-system components, and monocrystalline silicon wafers, as well as enhancing the recycling efficiency of discarded photovoltaic systems, is key to reducing energy consumption and carbon emissions. Additionally, transportation distance and installation location can impact the energy payback period and carbon payback period.

In order to further investigate the mechanism of grid-forming control to enhance the stability of the system, this paper firstly establishes the mathematical models of grid-following and grid-forming control, and analyzes the grid-connected oscillation characteristics of the two through the eigenvalue analysis method. Secondly, based on the deficiencies in the calculation of short-circuit ratio of existing renewable energy stations, a correction method for the calculation of equivalent short-circuit ratio of hybrid systems of grid-following and grid-forming is proposed. Subsequently, the article quantitatively deduces the change rule of system short-circuit capacity and equivalent short-circuit ratio caused by the access of grid-forming control units to the system of grid-following units, proves that the process of increasing the proportion of grid-forming units can effectively improve the stability of the system from the point of view of improving the system short-circuit ratio of grid-following units, and verifies the validity of the obtained conclusions based on the electromagnetic transient simulation model.

To address the challenges to grid security posed by the randomness, intermittency, and fluctuations of photovoltaic （PV） power in PV power generation planning, an innovative deep learning model—the DRSTCG-GPR model based on fused spatiotemporal feature extraction—is proposed. This model fuses spatiotemporal features, introduces soft thresholding and attention mechanisms into the residual module, automatically optimizes hyperparameters via a Bayesian algorithm, and quantifies the uncertainty of predictions using Gaussian process regression, ultimately achieving high-precision interval prediction for short-term photovoltaic （PV） power.. Experimental comparisons show that, compared to traditional CNN, GRU, and CGRU models, this model exhibits significant advantages in point prediction accuracy （R² improvement of 2.20%）, interval prediction coverage performance （I_CP improvement of 2.10%）, and probabilistic prediction reliability.