最新刊期
卷 58 ， 期 9 ， 2024
- 摘要：In this study, a combination of air separation unit and liquid air energy storage technology is employed to realize large-scale power demand management of a cryogenic air separation system. The surplus air is compressed, liquefied and stored during valley electricity periods, while the stored liquid air is directly recycled to the distillation column as raw material during peak electricity periods, thus increasing valley electricity consumption and decreasing peak electricity consumption. An air separation unit with liquid air energy storage(ASU-LAES)system producing oxygen with a standard state volume flow rate of 10 165 m3/h shifts the annual compression electricity consumption by 20% from peak periods to valley periods, resulting in a saving of 1.3%—6.8% per year on the electricity costs as compared to a conventional air separation system. The daily compression electricity consumption for oxygen production is 0.349 kW·h/m3. The equipment investment is RMB 4 034.8×104. The dynamic payback period is 4.6—5.2 a. The ASU-LAES system helps to reduce the peak power supply pressure of the power grid, takes advantage of the peak-valley electricity price policy, and brings economic benefits to the system.关键词：air separation;liquid air energy storage;equipment investment;dynamic payback period348|41|0更新时间：2025-07-28
- 摘要：To address the challenges of low CO2 mass transfer efficiency and solubility in microalgae photobioreactors in direct air carbon capture, this paper employs experimental methods to prepare a nylon fiber membrane coated with carbonic anhydrase(CA). By utilizing CA's catalytic properties to convert CO2 into bicarbonate, a novel photobioreactor is proposed to enhance CO2 solubility and conversion rate in microalgae solutions. The reactor's performance, with and without the CA-coated nylon floating membrane, is evaluated for microalgae cultivation and carbon sequestration. Furthermore, the impact of membrane porosity and CA loading on carbon fixation efficiency is investigated. The experimental results demonstrate that the prepared CA-coated nylon fiber membrane increases the CO2 conversion rate by 62.7%. Through durability testing, the CA activity remains robust even after five cultivation cycles, with only an 11.3% decline in performance. Compared to traditional aeration methods, the novel photobioreactor increased microalgae biomass production by 29.7% and carbon sequestration efficiency by 65%. Moreover, an increase in membrane porosity and light transmittance enhances the carbon sequestration efficiency per unit of CA loading, showing a 13% improvement in the carbon fixation rate per unit of CA for the control group with a 24.75% open area ratio compared to the non-porous control. This study provides a novel approach for further enhancing the carbon sequestration efficiency of microalgae in direct air capture.关键词：microalgae photobioreactor;direct air carbon capture;carbonic anhydrase;nylon membrane139|14|0更新时间：2025-07-28
- 摘要：This study utilizes the finite volume method to construct a dynamic simulation model for a MW-level CaO/CaCO3 fluidized bed reactor used in the sCO2 solar thermal power plant. The aim is to gain insights into the dynamic characteristics of the CaO/CaCO3 fluidized bed reactor during its energy release process and enhance its system design and safety control. The dynamic response characteristics of the reactor system under typical disturbances are investigated, and a sensitivity analysis is conducted on the influence of key parameters on heat and mass transfer during the energy release process of the CaO/CaCO3 fluidized bed reactor. Results indicate that altering the inlet flow rate and temperature of sCO2 on the absorptive side significantly affects the outlet temperature. Compared to changing the particle's inlet temperature on the exothermic side, adjusting the particle's inlet flow rate has a greater impact on the outlet temperature. A step disturbance of 10% in the inlet flow rate of exothermic-side particles can result in temperature fluctuations up to 17.5 ℃ at the outlet of the sCO2 on the absorptive side. In contrast, a similar percentage disturbance in the inlet temperature can only lead to a maximum temperature change of 3.9 ℃ at the outlet of the sCO2 on the absorptive side. Furthermore, increasing the number of tubes, reducing tube diameter, and decreasing particle size contribute to improving the thermal efficiency and conversion rate of the CaO/CaCO3 fluidized bed reactor. Increasing the number of tubes shows the most obvious effect. When the number of tubes increases from 20 to 40, the thermal efficiency and CaO particle conversion rate of the reactor rises by 2.9% and 2.4%, respectively. These research findings can guide the integration and design of CaO/CaCO3 thermochemical energy storage and solar thermal power generation systems.关键词：solar thermal power;CaO/CaCO3;fluidized bed reactor;dynamic characteristics126|23|0更新时间：2025-07-28
- 摘要：Direct contact condensation of a steam jet in flowing water in the pipe will cause intense interface oscillations and sound pressure oscillations. In this paper, a high-speed camera and a high-frequency hydrophone is used to capture the evolution of the jet interface and the induced sound pressure. The radial and axial oscillations and sound pressure oscillations of the jet interface under three typical condensation regimes is studied. Probability density function of sound pressure fluctuation shows a left-skewed unimodal distribution under the Chugging regime, a bimodal distribution under the Oscil-Ⅰ condensation regime, and a symmetrical unimodal distribution under the Stable regime. The intensities of the interface oscillation and sound pressure oscillation decrease as the steam mass flux increases, indicating a strong correlation. A jet penetration length prediction model based on the sound pressure parameter is established, and the error between the predicted value and the experimental value is within ±1%. Probability density and correlation analysis provide quantitative confirmation that the sound pressure oscillation of steam jet condensation is caused by its interface oscillations.125|13|0更新时间：2025-07-28
- 摘要：To carry out high-precision design calculations and optimization analyses for a large horizontal-tube falling film evaporator, an intelligent simulation model for heat exchange of the falling film evaporator is established, and performance analysis research is conducted on the evaporator. Firstly, a simulation model for heat exchange of a single-outlet horizontal-tube falling film evaporator is constructed based on a distributed parameter model. Secondly, the Bayesian optimization algorithm and experimental data from the evaporator are used to identify the parameters of the model. This approach improves the prediction accuracy and adaptability of the simulation model for heat exchange. Finally, the changes in heat transfer coefficient and heat flux along the axis of the tube are explored, and the influence of the proportion of heat transfer area in the flooded zone on the heat transfer of the evaporator is examined. The research findings show that the intelligent simulation model, integrating the distributed parameter method and Bayesian optimization algorithm, achieves a ±6% prediction error for heat transfer in the evaporator across 19 operating conditions. Within a wide range of heat exchange, the optimal proportion of heat transfer area in the flooded zone remains unchanged. Optimization from the perspectives of convective heat transfer inside the tube and secondary liquid distribution will effectively improve the performance of heat transfer of the falling film evaporator.关键词：falling film evaporator;distributed parameter model;Bayesian optimization;parameters identification123|11|0更新时间：2025-07-28
- 摘要：The deformation characteristics of bristle packs under aerodynamic load are investigated using a fluid-structure coupling method that combines numerical simulation of leakage flow of a three-dimensional staggered tube bundle with a finite element analysis model. The aerodynamic loads of the bristle pack are derived from the numerical solution of the three-dimensional Reynolds averaged Navier-Stokes(RANS)equations using the SST k-ω turbulence model. The friction contact force within the bristle pack is comprehensively considered in the finite element contact model. Results show that as the pressure ratio increases(1.5 to 3.0), the trend of the increase in the leakage flow coefficient of the brush seal gradually slows down, and the pressure drop across the 5th to 9th row of bristles accounting for the overall pressure differential increases from 60% to 70%. The rotational speed exhibits minimal influence on the leakage flow field of the brush seal. Circumferential and radial forces are nearly equal in magnitude, with the direction of the resultant force perpendicular to the bristle. The axial flow force is 13.6—18 times greater than the circumferential/radial force. The large axial airflow force causes the bristle to bend axially downstream in the fence height region. When the pressure ratio is 1.5, 2.0, 2.5 and 3.0, the maximum axial deformation of the bristle is measured at 0.077, 0.096, 0.114, and 0.130 mm, respectively. Minimal circumferential and radial deformation of the bristle pack is observed due to the small circumferential/radial forces and the large frictional contact force between the bristle and the backing plate. The ratio of axial aerodynamic force to the normal force of the bristle pack can be used to analyze the circumferential slip deformation of bristle rows. The fluid-structure interaction analysis method based on the staggered tube bundle model of the brush seal provides a research approach for analyzing the mechanical deformation of the bristle pack.关键词：brush seal;bristle pack;staggered tube bundle;deformation198|24|0更新时间：2025-07-28
- 摘要：In response to the problems such as unclear ignition mechanism of aluminum-steam and lack of fundamental combustion experimental data in water ramjet, this study carries out aluminum-steam two-phase self-ignition experiments and theoretical research based on the visualized high-pressure shock tube experimental platform. The temperature effect, pressure effect and scale effect of aluminum are presented from three perspectives: luminous intensity and flame image, self-ignition temperature and ignition delay time. The study reveals the difference of ignition mechanism for aluminum in steam and oxygen and develops the prediction model of aluminum-steam self-ignition temperature. The experimental results demonstrate that the ignition of aluminum-steam follows a mode where small-sized particles are preferentially ignited, subsequently the larger particles. The critical self-ignition temperature is inversely dependent on the aluminum particle size. The relation between ignition delay time and temperature conforms to the Arrhenius relation, with smaller particles exhibiting higher temperature sensitivity in ignition delay time. The ignition delay time of nano-sized aluminum powder exhibits a pronounced pressure-dependent behavior, and with the flame area exhibiting more concentrated under high pressure conditions, the oxidizer competition among aluminum powder particles is more intense. The scale effect on aluminum powder ignition delay time is obvious, and the ignition delay time of 50 μm aluminum powder at 1 500 K is about 30 times that of 100 nm aluminum powder. It is found that aluminum-steam self-ignition characteristic is superior to aluminum-oxygen, and the established aluminum-steam model demonstrates a minor deviation from experimental data in existing literature regarding the self-ignition temperature of micron-sized particles. The fundamental combustion data and theoretical analysis of ignition mechanism in this study offer a theoretical basis for combustion structure optimization and combustion chamber structure design of aluminum water ramjet and present valuable research insights for the development of aluminum-steam ignition mechanism and model.96|80|0更新时间：2025-07-28
- 摘要：A method of multidimensional optimization placement of turbopump sensors is proposed to address the issues of missing structurally important modal information and incomplete extraction of fault-sensitive information during the health monitoring of liquid rocket engine turbopumps. Experimental verification is conducted using a fault simulation test bench. Firstly, a finite element model of the turbopump's optimization area is established to conduct structural constrained modal analysis and transient dynamic analysis of bearing faults. Subsequently, candidate points for sensor placement are indentified based on the discrete artificial bee colony algorithm and transient analysis results. The final sensor placement method is determined through a comprehensive multidimensional evaluation method of sensors. Finally, the comprehensive indicators between the proposed sensor placement method and the traditional method are experimentally compared. The calculation results show that, compared with effective independence, after optimizing the placement of measurement points, sensor monitoring signal modal shape compliance increased by 20.1%, and the accuracy of bearing fault detection increased by 27.5%. This verifies that the multidimensional optimization placement method has good comprehensive performance in fault diagnosis.关键词：liquid rocket engine turbopump;sensor optimization placement;turbopump;discrete artificial bee colony algorithm;transient dynamics analysis;multidimensional evaluation237|13|0更新时间：2025-07-28
- 摘要：A scale-aware modulation swin transformer(SMST)model is proposed based on multi-domain fusion and lightweight structure, for axlebox bearing fault diagnosis, aiming to address the inefficiency of the current Transformer network model and its unsuitability for axlebox bearing fault diagnosis of high-speed trains under complex working conditions. Firstly, Gram angle field(GAF), bispectrum, and Chirplet transform techniques are applied to convert the bearing vibration signals into two-dimensional images in time, frequency, and time-frequency domains, which are integrated into a new image based on the idea of multi-domain feature fusion. Then, a new lightweight structure SMST module is designed, combining the further fusion of convolution operation and Transformer self-attention operation. Finally, a feature pyramid block(FPB)is introduced into the SMST hierarchical model framework to address the inconsistency of the output features across layers and enable deep feature fusion with contextual information. The fault diagnosis of axlebox bearings under complex working conditions is realized. Results show that the time-frequency multi-domain fusion method offers a superior representation of image feature information compared to single-domain image generation methods such as Gram angle field, bispectrum, Chirplet transform, short-time Fourier transform, and continuous wavelet transform. The proposed network model achieves high accuracy rates of 99.88%, 99.92%, and 99.96% in identifying axlebox bearing faults in the three tasks under variable working conditions with different speeds of 1 010 r/min, 760 r/min, and 505 r/min, respectively. Comparative analysis against five models of ResNets, GoogleNet, ViT, Swin Transformer, and SMT showcases the higher fault identification accuracy and better model lightweight of the proposed method. The proposed method can serve as a reference for the diagnosis of axlebox bearing faults in trains under actual working conditions.关键词：fault diagnosis;axlebox bearing;multi-domain fusion;lightweight;scale-aware modulation137|10|0更新时间：2025-07-28
- 摘要：In response to the significant imbalance between the quantities of qualified and non-qualified results in the radiographic testing(RT)of the investment precision casting process parameters dataset, this paper proposes a casting quality prediction method using SyMProD-Stacking ensemble learning. The method begins by preprocessing the original dataset to ensure data quality. It then employs Z-scores to eliminate noisy data, assigns a probability to each minority class instance(non-qualified castings), and generates sample data based on this probability distribution to obtain a balanced dataset. XGBoost is used to rank the importance of all process parameter features and removes some of the lower-ranking parameters. Finally, the LightGBM, RF, SVM, and XGBoost models are stacked together through ensemble learning, and a quality prediction model is constructed using the balanced dataset. Taking the precision casting process in the manufacturing of high-temperature turbine blades as an example, the proposed quality prediction method is validated. The results indicate that the predictive model constructed using the SyMProD oversampling method significantly outperforms the model built from the original dataset, with a 75.4% improvement in the accuracy of predicting non-qualified castings. Stacking ensemble learning, compared to individual algorithm models, achieves improvements of 5.48%—11.59%, 3.78%—8.92%, and 5.72%—11.39% in terms of area under curve, geometric mean, and F1, respectively.关键词：high-temperature turbine blades of heavy-duty gas turbine;imbalanced dataset;oversampling methods;ensemble learning;quality prediction89|9|0更新时间：2025-07-28
- 摘要：A dynamic layer-wise gradient sparsity and gradient aggregation optimization strategy for deep neural networks is proposed to address the challenges posed by substantial communication overhead, prolonged training duration, and suboptimal resource utilization associated with the acceleration of large-scale deep neural networks through data parallelism. Initially, a dynamic layer-wise gradient sparsity optimization method is proposed by combining gradient sparsity compression with pipeline parallelism. Each neural network layer is assigned an appropriate threshold, which is adjusted dynamically in subsequent iterations to achieve adaptive compression of gradient transmission for each layer. Subsequently, a layer-wise gradient merging method is introduced. Leveraging dynamic programming, this method optimizes communication overhead, sparsity, and layer gradient computation time during layer-wise gradient merging, determining the optimal combination for merging multiple layers of small-scale gradient tensors into a single communication layer. This aims to reduce the high communication latency introduced during layer-wise gradient decision-making. Finally, the determined optimal layer-wise gradient merging combination is applied to the specific training iteration process. Experimental results demonstrate that the proposed method, compared to existing methods, significantly reduces communication overhead and enhances model training speed while ensuring model training accuracy. It achieves a maximum training speed up of 1.99 times compared to the uncompressed method.关键词：deep neural network;distributed training;synchronous data parallelism;gradient compression;layer gradient merging130|5|0更新时间：2025-07-28
- 摘要：Aiming at multimodal and high-dimensional characteristics in feature selection problems, a new population initialization strategy is introduced to improve the large-scale multimodal multiobjective optimization algorithm, and a high-dimensional multimodal feature selection algorithm based on evolutionary multiobjective optimization is proposed. The original continuous optimization algorithm is discretized to evaluate individuals in discrete optimization problems. This approach is validated across six high-dimensional feature selection datasets. Results demonstrate that the proposed algorithm improves the quality of the initial population and accelerates algorithm convergence. Compared to other algorithms, the proposed algorithm yields the superior Pareto front with the best overall hypervolume value. It can obtain an average of 2.53 equivalent feature subsets without compromising classification accuracy. These results show the proposed algorithm's ability to achieve optimal classification accuracy and the most diverse equivalent feature subsets.关键词：classification;feature selection;evolutionary computation;multimodal multiobjective optimization;high-dimension multimodal feature selection82|25|0更新时间：2025-07-28
- 摘要：To detect acetylene gas dissolved in transformer oil, an acetylene gas sensor based on Au decorated SnO2 gas sensing thin film is developed. SnO2 thin films were prepared using radio frequency magnetron sputtering followed by the deposition of Au using direct current magnetron sputtering. The different amounts of Au decoration were realized by adjusting the deposition time.Then the acetylene gas sensing chips, based on gas sensing thin films, are fabricated using the process of micro electro mechanical systems(MEMS). The sensing properties of the pure SnO2 and Au decorated SnO2 films are compared. The results indicates that the sensor using the 20 s-Au decorated SnO2 film shows superior performance, operating optimally at 200 °C. It exhibits a response value of 14 to acetylene gas at a volume fraction of 1×10-6, with response and recovery times of 5 s and 87 s, respectively. The sensor exhibits excellent repeatability, with a detection limit of 0.1×10-6 in volume fraction. In comparison testing against hydrogen, methane, and other gases dissolved in the transformer oil at a concentration of 1×10-6 volume fraction, the sensor has a good selective response to acetylene and maintains excellent performance stability over long-term testing. It can serve as a component selection for addressing the challenge of detecting dissolved acetylene gas in transformer oil.关键词：transformer oil;acetylene;au decoration;tin dioxide;gas sensor128|23|0更新时间：2025-07-28
- 摘要：To address the issues of low detection accuracy and slow detection speed caused by the influence of complex environments on detecting foreign objects of different scales on railroad tracks, this paper proposes a multi-scale feature fusion RMF-YOLO(railway multi-scale fusion YOLO)method for railroad track foreign object detection. Firstly, ICBAM, an improved convolutional attention module, is designed and introduced in combination with the YOLOv7 feature extraction network to enhance feature extraction capability in complex scenarios. Subsequently, GhostConv is adopted in all efficient layer aggregation network modules instead of regular convolutional layers to reduce computational complexity and enhance feature output efficiency.An improved weighted bi-directional feature pyramid network(N-BiFPN)structure is introduced to enhance multi-scale feature fusion, balance feature information across different levels, and improve multi-scale detection capabilities. Lastly, to further enhance detection accuracy, the WIoU loss function combined with the dynamic non-monotonic aggregation mechanism is used to effectively deal with the gradient generated by the low-quality anchor frames and to improve the overall performance of the model for the detection of foreign objects at different scales. The experimental results indicate that on the self-made railway track foreign object dataset, the RMF-YOLO algorithm reduces the parameter count of the original network model, effectively enhancing the model's detection accuracy and detection speed of the model and addressing issues related to missed and false detections. On average, the precision increased by 5.5%, the frames per second(FPS)improved by 5.88%, and the computational load decreased by 12.25%. These enhancements meet the requirements for both detection accuracy and real-time performance in railway track foreign object detection.关键词：railroad foreign object detection;feature fusion;multi-scale;YOLOv7;loss function257|24|0更新时间：2025-07-28
- 摘要：To solve the problem of insufficient structural strength of two gap gas spark switches for controllable shock wave equipment in unconventional shale oil development, this paper proposes a design method for synchronously optimizing the structural strength and electric field distribution of gas spark switches in high static pressure and limited space. Based on finite element simulation and theoretical analysis, the impact of 50 MPa external high static pressure on the structural strength of the gas spark switch is evaluated. For a gas spark switch model with sufficient structural strength, the electric field distribution inside the switch is optimized and analyzed through Gauss' theorem, leading to a design scheme for synchronously optimizing the structural strength and electric field distribution of a two electrode gas spark switch. The research results indicate that the strength of the switch structure is primarily positively correlated with the chamber wall thickness, and the increase in wall thickness may increase the probability of abnormal discharge of the switch. Under specific wall thickness parameters, there is an optimal value for the electrode radius to make the electric field intensity on the insulator surface the lowest. On the premise of ensuring the structural strength, the existing switch electric field distribution is optimized and analyzed. The optimized switch gap exhibits a slight improvement in the uniformity of the electric field, and the electric field intensity on the inner and outer surfaces of the high-voltage insulator is respectively reduced by 59.6% and 31.0%. By first increasing the structural strength and then optimizing the electric field distribution, synchronous optimization of the structural strength and electric field distribution of the two electrode gas spark switch in shock wave equipment is achieved.关键词：spark gap switch;finite element;high hydrostatic pressure;electric field distribution79|7|0更新时间：2025-07-28
- 摘要：An online state of charge estimation algorithm for ternary lithium batteries is proposed based on online calculation of open circuit voltage and table lookup method. Firstly, the first-order Thevenin equivalent model is applied to the lithium battery, and the relationship between port voltage, port current, and open circuit voltage is derived through the equivalent circuit model. Then, the recursive least squares method is used to solve the open circuit voltage online, and real-time calculation of the approximate open circuit voltage is achieved through the port voltage and current parameters during the operation of the lithium battery. Finally, the implementation process of the proposed online state of charge estimation algorithm is introduced, and the estimation accuracy, computational complexity, and other performance of the proposed algorithm are compared, analyzed, and experimentally verified using typical datasets. The experimental results show that the estimation error of the proposed online state of charge estimation algorithm is less than 15%, and the computational speed is 2.5 times that of the extended Kalman filter method. This indicates that the proposed online state of charge estimation algorithm has high accuracy and low computational complexity, which make it suitable for online state of charge estimation.关键词：lithium battery;equivalent circuit model;open circuit voltage calculation;online state of charge estimation;low computational burden;parameter estimation88|55|0更新时间：2025-07-28
- 摘要：A high-speed serial transmitter circuit compliant with the JESD204B protocol is designed in this paper, aiming to address the non-ideal factors such as channel attenuation, noise, and crosstalk faced by the transmitter circuit of high-speed Serial/De-serial interface(SerDes)in high-speed and high-precision analog-to-digital converters(ADCs). The design employs several techniques such as matching impedance calibration, feed-forward equalization, and T-coil to improve the quality of data transmission. In addition, to tackle the sensitivity of the current half-rate transmitter architecture to variation in the input clock duty cycle, a duty cycle calibration circuit is devised to stabilize the duty cycle of the output clock. Besides, the source-series-terminated(SST)driver architecture with multiple parallel slices is adopted to realize the combination of matching impedance calibration and feed-forward equalization scheme, significantly reducing circuit complexity, area occupation, and power consumption of the transmitter. The transmitter is designed and fabricated in a 28 nm CMOS process. Measurement results show that, at a transmission rate of 16 Gb/s, the transmitter achieves an eye height of 811 mV, an eye width of 58.8 ps, a total jitter of 7.35 ps, a power consumption of 49.2 mW, and an energy efficiency rate of 3.07 pJ/bit. The layout area measures 300×150 μm2. The transmitter showcases significant advantages in terms of jitter performance, energy efficiency, and circuit area while meeting protocol requirements.关键词：transmitter;impedance calibration;duty cycle calibration;T-coil;source-series-terminated76|57|0更新时间：2025-07-28
- 摘要：To alleviate muscle fatigue caused by neuromuscular electrical stimulation(NMES)and reduce the discomfort associated with high-frequency carrier pulse cluster electrical stimulation, this paper compares the anti-fatigue properties of the proposed asymmetric high-frequency carrier pulse cluster electrical stimulation with the conventional symmetric biphasic rectangular pulse electrical stimulation technique in healthy subjects. Specifically, the clustered narrow pulses with a carrier frequency of 10 kHz(high-frequency mode, HF)and the conventional symmetrical biphasic rectangular pulses(low-frequency mode, LF)are delivered to the proximal segment of the median/ulnar nerve bundles, eliciting the same level of contraction. Stimulation is continued for 5 minutes to induce muscle fatigue, and finger flexion forces and high-density electromyography(EMG)signals of the finger flexors are recorded. The results show that the rate of muscle fatigue is significantly reduced under the HF stimulation compared with the LF stimulation. This is manifested by a slower force decay rate, smaller absolute force decay(3.868 8±1.136 8)N, and a larger force plateau(7.296±1.342 4)N, resulting in greater force output(2 282.8±341.48)N·s. The higher force-to-EMG amplitude ratio under the HF stimulation indicated a higher efficiency of muscle activation, which may be a potential mechanism for alleviating muscle fatigue by the HF modes. The present study suggests that the asymmetric pulse clusters at a kilohertz carrier frequency may significantly alleviate muscle fatigue by inducing a higher efficiency of muscle activation compared to the conventional symmetric LF stimulation, which can potentially promote the application of the NMES-based motor neurorehabilitation technique in stroke patients.关键词：neuromuscular electrical stimulation;high-frequency stimulation;electromyographic signal;muscle fatigue83|18|0更新时间：2025-07-28
- 摘要：The emission of high directional acoustic beams without sidelobes, along with the low resistance of transmitting devices to error factors, has been a challenging issue in beamforming. In this paper, a mechanism of topological acoustic beamforming with high performance under rotation-induced mode of the scatterer is proposed under the bulk-boundary correspondence relationship of the acoustic topological insulator by rotating the scatterer. The modulation of the modal coupling by the rotating scatterer enables the beam to have varying width crest and beam energy attenuation rates across a wide band without sidelobes in both near field and far field. By introducing error factors into the structure, it is found that the topological acoustic high performance beamforming device has high fault tolerance, and multiple error factors do not affect the near and far field results of beamforming, which greatly reduces the difficulty of manufacturing and greatly improves the service life of the device. The topological acoustic beamforming and the beamforming under the involvement of error factors are experimentally verified. The experimental results demonstrate the achievement of wide peak beams without sidelobes across a wide band of 4 100—4 360 Hz and confirm the high fault tolerance of the beamformers when some scatters are missing in the device. This study proposes a new beamforming method that has can provide a reference for the engineering applications of acoustic communication, micro and nano manufacturing, biomedicine, and other micro-shaped and multi-functional acoustic devices and inspires other classical wave fields such as light and electromagnetic waves.关键词：beamforming;topological acoustics;high fault tolerance;modal coupling;without sidelobe257|24|0更新时间：2025-07-28
- 摘要：To address the problem of low corrosion resistance of T91 steel, a structural material used in nuclear reactors, in lead-bismuth alloy liquid, this paper employs a combination of thermodynamic simulation and first-principles calculations to investigate the mechanism of enhancing the corrosion resistance of T91 steel at the atomic scale with alloying elements Cr, Ni, Mn and Cu. Through thermodynamic simulation calculations research, the main phase composition of T91 steel at room temperature is determined to be martensite, and four first-principles calculation models, namely martensite-Cr, martensite-Ni, martensite-Mn, and martensite-Cu, are established and used to calculate and compare electronic structure and charge density distribution. It is found that a metallic bond is formed between the alloying elements and Fe atoms. Differential charge studies show that the metal bond between Cr and Fe atoms has strong covalent bond characteristics and the strongest bonding, while the metal bond between Ni and Fe atoms also has certain covalent bond characteristics, but its bonding is weaker than Cr, followed by Cu and Mn atoms. Additionally, the binding energy between the alloying elements and the substrate in the four models is calculated, with the martensite-Cr model exhibiting the lowest energy and a strong binding between Cr and the substrate. This effectively demonstrates that Cr atoms can improve the corrosion resistance of T91 steel. Overall, this study provides valuable insights for enhancing the corrosion resistance of T91 steel to lead-bismuth alloy using Cr, Ni, Mn and Cu, and also presents a novel research method for the development and performance prediction of new materials.关键词：T91 steel;corrosion resistance;first-principles calculations;alloying element125|24|0更新时间：2025-07-28
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