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Role of unsteady tip leakage flow in acoustic resonance inception of a multistage compressor

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Chinese Journal of Aeronautics 2023年第10期36卷 165-181页

作者： Xiaohua LIU zihao wu Changxin SI Jun YANG Xiaofeng SUN School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory(Fluid Machinery and Engineering Research Base)of Sichuan Province Xihua UniversityChengdu 610039China China Three Gorges Investment Management Co.Ltd Shanghai 200124China School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China Research Institute of Aero-Engine Beihang UniversityBeijing 100191China

In previous studies,a theoretical model was developed after Acoustic Resonance(AR)was experimentally detected in a four-stage compressor,and AR inception was proposed to be triggered by an unknown sound source,which is a pressure perturbation of a specific frequency with a suitable circumferential propagation *** present paper,which is not dedicated to the simulation of acoustic field,aims to identify the specific sound source generated by the unsteady tip leakage flow using the unsteady Computational Fluid Mechanics(CFD)*** a comprehensive analysis of an Unsteady Reynolds Averaged Navier-Stokes(URANS)simulation,a pressure perturbation of non-integer multiple of rotor frequency is found at the blade *** the essence of the tip leakage flow is a jet flow driven by the pressure difference between two sides of blade,a simplified tip leakage flow model is adopted using Large Eddy Simulation(LES)in order to simulate the jet flow through a tip *** is found that the convection velocity of shedding vortices fits the expected propagation speed of the sound source,the frequency is also close to one of the dominating frequencies in the URANS simulation,and the resultant combination frequency coincides with the experimentally measured AR *** such a simplified model successfully captures the key physical mechanisms,it is concluded that this paper provides a piece of unambiguous evidence on the role of unsteady tip leakage vortex in triggering the AR inception of the multistage compressor.

关键词： Acoustic Resonance(AR) Jet flow Multistage compressor Tip leakage flow Unsteady flow

Prediction of discharge in a tidal river using the LSTM-based sequence-to-sequence models

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Acta Oceanologica Sinica 2024年第7期43卷 40-51页

作者： Zhigao Chen Yan Zong zihao wu Zhiyu Kuang Shengping Wang Key Laboratory of Mine Environmental Monitoring and Improving around Poyang Lake of Ministry of Natural Resources East China University of TechnologyNanchang 330013China School of Surveying and Geoinformation Engineering East China University of TechnologyNanchang 330013China

The complexity of river-tide interaction poses a significant challenge in predicting discharge in tidal *** short-term memory(LSTM)networks excel in processing and predicting crucial events with extended intervals and time delays in time series ***,the sequence-to-sequence(Seq2Seq)model,known for handling temporal relationships,adapting to variable-length sequences,effectively capturing historical information,and accommodating various influencing factors,emerges as a robust and flexible tool in discharge *** this study,we introduce the application of LSTM-based Seq2Seq models for the first time in forecasting the discharge of a tidal reach of the Changjiang River(Yangtze River)*** study focuses on discharge forecasting using three key input characteristics:flow velocity,water level,and discharge,which means the structure of multiple input and single output is *** experiment used the discharge data of the whole year of 2020,of which the first 80%is used as the training set,and the last 20%is used as the test *** means that the data covers different tidal cycles,which helps to test the forecasting effect of different models in different tidal cycles and different *** experimental results indicate that the proposed models demonstrate advantages in long-term,mid-term,and short-term discharge *** Seq2Seq models improved by 6%-60%and 5%-20%of the relative standard deviation compared to the harmonic analysis models and improved back propagation neural network models in discharge prediction,*** addition,the relative accuracy of the Seq2Seq model is 1%to 3%higher than that of the LSTM *** assessment of the prediction errors shows that the Seq2Seq models are insensitive to the forecast lead time and they can capture characteristic values such as maximum flood tide flow and maximum ebb tide flow in the tidal cycle *** indicates the significance of the Seq2Seq models.

关键词： discharge prediction long short-term memory networks sequence-to-sequence(Seq2Seq)model tidal river back propagation neural network Changjiang River(Yangtze River)Estuary

Flexible Vis/NIR wireless sensing system for banana monitoring

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Food Quality and Safety 2023年第3期7卷 492-502页

作者： Meng Wang Bingbing Wang Ruihua Zhang zihao wu Xinqing Xiao College of Engineering China Agricultural UniversityBeijingChina

Objectives:The quality of the fruit seriously affects the economic value of the *** quality is related to many ripening parameters,such as soluble solid content(SSC),pH,and firmness(FM),and is a complex *** methods are inefficient,do not guarantee quality,and do not adapt to the current rhythm of the fruit *** this paper,a was designed and implemented for quality prediction and maturity level classification of Philippine Cavendish *** and Methods:The quality changes of bananas in different stages were *** light intensity reflectance values for each maturity stage were compared to conventionally measured SSC,FM,PH,and color ***:Our device can be compared with traditional forms of quality *** experimental results show that the established predictive model with specific preprocessing and modeling algorithms can effectively determine various banana quality parameters(SSC,pH,FM,L^(*),a^(*),and b^(*)).The RPD values of SSC and a^(*)were greater than 3.0,the RPD values of L^(*)and b^(*)were between 2.5 and 3.0,and the pH and FM were between 2.0 and *** addition,a new banana maturity level classification method(FSC)was proposed,and the results showed that the method could effectively classify the maturity level classes(*** maturity levels)with an accuracy rate of up to 97.5%.Finally,the MLR and FSC models are imported into the MCU to realize the near-range and long-range real-time display of ***:These methods can also be applied more broadly to fruit quality detection,providing a basic framework for future research.

关键词： Banana Vis/NIR flexibility ripening classification chemometrics

Transcriptome Analysis of Soybean in Response to Different Sulfur Concentrations

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Phyton-International Journal of Experimental Botany 2022年第6期91卷 1165-1182页

作者： Xiyue Wang Xiaomei Li zihao wu Shoukun Dong Northeast Agricultural University Harbin150030China Harbin Academy of Agricultural Science Harbin150029China

Sulfur is an indispensable nutrient for plant growth and development,and is important in the synthesis of sulfurcontaining amino *** several studies on the effects of some macronutrients,including nitrogen and phosphorus,have been conducted on the performance of several crops at the genomic level,studies on the effect of sulfur on crop performance are ***,this study aimed to examine the effect of different sulfur concentration on the transcriptome of ***,soybean yield parameters were also *** soybean varieties,DND252 and HN84,were exposed to low and high concentrations of sulfur,and differentially expressed genes(DEGs)were identified using transcriptome *** study results showed that the DEGs identified in the DND252 variety were involved in stimuli response,DNA binding and cell periphery under low sulfur ***,the DEGs identified under high sulfur concentration were involved in membrane and membrane ***,DEGs identified in the HN84 variety under low sulfur concentrations had similar functions as those identified in DND252 under high sulfur concentrations,indicating that HN84 was more sensitive to sulfur concentration changes than ***,under higher sulfur concentrations,the DEGs identified in HN84 were primarily involved in membrane and membrane parts,indicating that high sulfur can cause cell membrane ***,soybean grown using 2.0 mmol/L sulfur had the best *** findings of this study identified candidate genes for the breeding and development of sulfur-efficient soybean varieties.

关键词： Soybean sulfur transcriptome

A Secure and Effective Energy-Aware Fixed-Point Quantization Scheme for Asynchronous Federated Learning

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Computers, Materials & Continua 2023年第5期75卷 2939-2955页

作者： Zerui Zhen zihao wu Lei Feng Wenjing Li Feng Qi Shixuan Guo Beijing University of Posts and Telecommunication Beijing100876China Vanderbilt University Nashville TN37240USA

Asynchronous federated learning(AsynFL)can effectivelymitigate the impact of heterogeneity of edge nodes on joint training while satisfying participant user privacy protection and data ***,the frequent exchange of massive data can lead to excess communication overhead between edge and central nodes regardless of whether the federated learning(FL)algorithm uses synchronous or asynchronous ***,there is an urgent need for a method that can simultaneously take into account device heterogeneity and edge node energy consumption *** paper proposes a novel Fixed-point Asynchronous Federated Learning(FixedAsynFL)algorithm,which could mitigate the resource consumption caused by frequent data communication while alleviating the effect of device *** uses fixed-point quantization to compress the local and global models in *** order to balance energy consumption and learning accuracy,this paper proposed a quantization scale selection *** paper examines the mathematical relationship between the quantization scale and energy consumption of the computation/communication process in the *** on considering the upper bound of quantization noise,this paper optimizes the quantization scale by minimizing communication and computation *** paper performs pertinent experiments on the MNIST dataset with several edge nodes of different computing *** results show that the FixedAsynFL algorithm with an 8-bit quantization can significantly reduce the communication data size by 81.3%and save the computation energy in the training phase by 74.9%without significant loss of *** to the experimental results,we can see that the proposed AsynFixedFL algorithm can effectively solve the problem of device heterogeneity and energy consumption limitation of edge nodes.

关键词： Asynchronous federated learning artificial intelligence model compression energy consumption fixed-point quantization learning accuracy

Rational Design of Porous N-Ti3C2 MXene@CNT Microspheres for High Cycling Stability in Li–S Battery

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Nano-Micro Letters 2020年第1期12卷 40-53页

作者： Jianli Wang Zhao Zhang Xufeng Yan Shunlong Zhang zihao wu Zhihong Zhuang Wei-Qiang Han School of Materials Science and Engineering Zhejiang University

Herein,N-Ti3C2@CNT microspheres are successfully synthesized by the simple spray drying *** the preparation process,HCl-treated melamine(HTM)is selected as the sources of carbon and *** not only realizes in situ growth of CNTs on the surface of MXene nanosheets with the catalysis of Ni,but also introduces efficient N-doping in both MXene and *** the microsphere,MXene nanosheets interconnect with CNTs to form porous and conductive *** addition,N-doped MXene and CNTs can provide strong chemical immobilization for polysulfides and effectively entrap them within the porous ***-mentioned merits enable N-Ti3C2@CNT microspheres to be ideal sulfur *** used in lithium–sulfur(Li–S)battery,the N-Ti3C2@CNT microspheres/S cathode delivers initial specific capacity of 927 mAh g−1 at 1 C and retains high capacity of 775 mAh g−1 after 1000 cycles with extremely low fading rate(FR)of 0.016%per ***,the cathode still shows high cycling stability at high C-rate of 4 C(capacity of 647 mAh g−1 after 650 cycles,FR 0.027%)and high sulfur loading of 3 and 6 mg cm−2 for Li–S batteries.

关键词： Spray drying method N-Ti3C2 MXene@CNT microspheres Nitrogen-doping High cycling stability Lithium-sulfur battery

Assessing comparable bioconcentration potentials for nanoparticles in aquatic organisms via combined utilization of machine learning and toxicokinetic models

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SmartMat 2023年第3期4卷 70-83页

作者： Shipeng Dong zihao wu Mingjie Wang Xiaoyan Sun Liang Mao State Key Laboratory of Pollution Control and Resource Reuse School of the EnvironmentNanjing UniversityNanjingChina Nanjing Qixia District Hospital NanjingChina

The toxicokinetic(TK)model‐derived kinetic bioconcentration factor(BCFk)provides a quantitatively comparable index to estimate the bioaccumulation potential of nanoparticles(NPs)that barely reach thermodynamic equilibrium in aquatic organisms,but experimental data are limited for various *** the present study,a machine learning model was applied to offer reliable in silico predictions for the dynamic body burden of diverse NPs to derive corresponding parameters for the TK *** developed eXtreme Gradient Boosting‐derived TK(XGB‐TK)model was applied to predict BCFk results for a broad range of metallic or carbonaceous NPs,with an appreciable prediction R2 of *** BCFk values were predicted based on a random combination of selected variable features,revealing that their bioaccumulation potential showed an overall negative correlation with NP density or organism *** applying importance analysis and partial dependence plots,NP density and organism size were revealed to be the top essential features that impact the bioaccumulation *** conjunctively used XGB‐TK model enabled a prior comparison for diverse NPs and straightforward derivation on the dependency of features,which could also guide the bioaccumulation mechanism exploration and experimental condition formulation.

关键词： aquatic organism BCF bioaccumulation machine learning nanoparticles toxicokinetic models

Adaptive smoothing length method based on weighted average of neighboring particle density for SPH fluid simulation

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Virtual Reality & Intelligent Hardware 2021年第2期3卷 129-141页

作者： Rongda ZENG zihao wu Shengbang DENG Jian ZHU Xiaoyu CHI School of Computer Science Guangdong University of TechnologyGuangzhou 510006China Qingdao Research Institute of Beihang University Qingdao 266000China

Background In the smoothed particle hydrodynamics(SPH)fluid simulation method,the smoothing length affects not only the process of neighbor search but also the calculation accuracy of the pressure ***,it plays a crucial role in ensuring the accuracy and stability of *** In this study,an adaptive SPH fluid simulation method with a variable smoothing length is *** this method,the smoothing length is adaptively adjusted according to the ratio of the particle density to the weighted average of the density of the neighboring ***,a neighbor search scheme and kernel function scheme are designed to solve the asymmetry problems caused by the variable smoothing *** The simulation efficiency of the proposed algorithm is comparable to that of some classical methods,and the variance of the number of neighboring particles is ***,the visual effect is more similar to the corresponding physical *** The precision of the interpolation calculation performed in the SPH algorithm is improved using the adaptive-smoothing length scheme;thus,the stability of the algorithm is enhanced,and a larger timestep is possible.

关键词： Fluid simulation SPH Smoothing length Adaptive Particle density

Proteomics Analysis of Soybean Seedlings under Short-Term Water Deficit

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Phyton-International Journal of Experimental Botany 2022年第7期91卷 1381-1401页

作者： Xiyue Wang zihao wu Chao Yan Chunmei Ma Shoukun Dong College of Agriculture Northeast Agricultural UniversityHarbin150030China

Soybeans are one of the most important grain crops *** deficit,which seriously affects the yield and quality of soybeans,is the main abiotic stress factor in soybean *** a follow-up study,the droughttolerant soybean variant Heinong 44 was analyzed via proteome *** was exposed to water deficit for 0,8,and 24 h,and protein samples were extracted for detection of differentially expressed *** sequencing of leaf tissues under water stress yielded a total of 549 differentially expressed proteins:75 and 320 upregulated proteins as well as 70 and 84 downregulated proteins were obtained after 8 and 24 h of water deficit,*** Ontology analysis revealed that most of the differentially expressed proteins(DEPs)were involved in catalytic activity,molecular function,and metabolic processes,whereas some of them were involved in photosynthesis,carbon metabolism,and energy *** also identified some differentially expressed proteins that may be involved in the regulation of water deficit *** study provides a theoretical basis for the breeding of drought-resistant soybean varieties.

关键词： Soybean water deficit proteomics stress time