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Electromagnetic characteristic analysis and design of a linear motor used for ultra-high-speed EMS maglev train

Science China Technological Sciences 2024年第6期67卷 1957-1973页

作者： GAO Han SHI TingNa GAO XinMai LEI yanXiao yan dong GUO Liyan yan yan College of Electrical Engineering Zhejiang University Zhejiang University Advanced Electrical Equipment Innovation Center State Key Laboratory of High-speed Maglev Transportation Technology CRRC Qingdao Sifang Co.Ltd.

The operating speed of the commercial electromagnetic suspension(EMS) maglev train has been over 430 km/h, making it the fastest means of land transportation. With the increasing demands of people traveling, it is necessary to further improve the operating speed of maglev trains. Aiming to examine whether the existing EMS system can meet the requirements of ultra-highspeed operation(more than 600 km/h), the electromagnetic characteristics of an EMS linear motor under the operating speed of 600–1000 km/h fed by a square-wave voltage supply is investigated in this article. First, an electromagnetic field model of the EMS system under the square-wave voltage supply is established to investigate its electromagnetic performance, e.g., the characteristics of phase current, the magnetic flux density, and the electromagnetic force. Second, the relationship between the harmonic components of the air-gap magnetic flux density and electromagnetic force is investigated using the two-dimensional fast Fourier transform(2D-FFT) to reveal the mechanism of electromagnetic force ripple. Third, to address the issues of excessive armature current density and significant electromagnetic force ripple, the linear motor is re-designed by enlarging the stator slot area and reshaping the mover's main magnetic poles. Furthermore, the Taguchi method is used to further improve the electromagnetic characteristics of the linear electric motor. Finally, the effectiveness of the proposed optimal design is validated by the finite-element analysis(FEA) based co-simulation.

关键词： ultra-high-speed maglev transportation electromagnetic suspension (EMS) linear motor electromagnetic force ripple suppression

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A Hybrid Level Set Optimization Design Method of Functionally Graded Cellular Structures Considering Connectivity

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Computers, Materials & Continua 2024年第4期79卷 1-18页

作者： yan dong Kang Zhao Liang Gao Hao Li The State Key Lab of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan430074China Institute of Systems Engineering China Academy of Engineering PhysicsMianyang621900China

With the continuous advancement in topology optimization and additive manufacturing(AM)technology,the capability to fabricate functionally graded materials and intricate cellular structures with spatially varying microstructures has grown significantly.However,a critical challenge is encountered in the design of these structures–the absence of robust interface connections between adjacent microstructures,potentially resulting in diminished efficiency or macroscopic failure.A Hybrid Level Set Method(HLSM)is proposed,specifically designed to enhance connectivity among non-uniform microstructures,contributing to the design of functionally graded cellular structures.The HLSM introduces a pioneering algorithm for effectively blending heterogeneous microstructure interfaces.Initially,an interpolation algorithm is presented to construct transition microstructures seamlessly connected on both sides.Subsequently,the algorithm enables the morphing of non-uniform unit cells to seamlessly adapt to interconnected adjacent microstructures.The method,seamlessly integrated into a multi-scale topology optimization framework using the level set method,exhibits its efficacy through numerical examples,showcasing its prowess in optimizing 2D and 3D functionally graded materials(FGM)and multi-scale topology optimization.In essence,the pressing issue of interface connections in complex structure design is not only addressed but also a robust methodology is introduced,substantiated by numerical evidence,advancing optimization capabilities in the realm of functionally graded materials and cellular structures.

关键词： Hybrid level set method functionally graded cellular structure connectivity interpolated transition optimization design

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A benchmark-based method for evaluating hyperparameter optimization techniques of neural networks for surface water quality prediction

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Frontiers of Environmental Science & Engineering 2024年第5期18卷 13-27页

作者： Xuan Wang yan dong Jing yang Zhipeng Liu Jinsuo Lu School of Environmental and Municipal Engineering Xi’an University of Architecture and TechnologyXi’an710055China Shaanxi Key Laboratory of Environmental Engineering Xi’an University of Architecture and TechnologyXi’an710055China State Key Laboratory of Green Building in West China Xi’an University of Architecture and TechnologyXi’an710055China

Neural networks(NNs)have been used extensively in surface water prediction tasks due to computing algorithm improvements and data accumulation.An essential step in developing an NN is the hyperparameter selection.In practice,it is common to manually determine hyperparameters in the studies of NNs in water resources tasks.This may result in considerable randomness and require significant computation time;therefore,hyperparameter optimization(HPO)is essential.This study adopted five representatives of the HPO techniques in the surface water quality prediction tasks,including the grid sampling(GS),random search(RS),genetic algorithm(GA),Bayesian optimization(BO)based on the Gaussian process(GP),and the tree Parzen estimator(TPE).For the evaluation of these techniques,this study proposed a method:first,the optimal hyperparameter value sets achieved by GS were regarded as the benchmark;then,the other HPO techniques were evaluated and compared with the benchmark in convergence,optimization orientation,and consistency of the optimized values.The results indicated that the TPE-based BO algorithm was recommended because it yielded stable convergence,reasonable optimization orientation,and the highest consistency rates with the benchmark values.The optimization consistency rates via TPE for the hyperparameters hidden layers,hidden dimension,learning rate,and batch size were 86.7%,73.3%,73.3%,and 80.0%,respectively.Unlike the evaluation of HPO techniques directly based on the prediction performance of the optimized NN in a single HPO test,the proposed benchmark-based HPO evaluation approach is feasible and robust.

关键词： Neural networks Hyperparameter optimization Surface water quality prediction Bayes optimization Genetic algorithm

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The Research on Open Sharing of Higher Education Park Based on Intelligent Security System

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Journal of Computer and Communications 2024年第3期12卷 101-106页

作者： yan dong Security Department Central University of Finance and Economics Beijing China

The intelligent security system is a series of systems that use modern information technology means such as artificial intelligence, cloud computing, big data, face recognition to carry out comprehensive monitoring, early warning, prevention and control, disposal, etc, for security protection. It is the development trend of security system in the future, and it is also the basis for open sharing between higher education parks and universities. By using content analysis, unstructured interviews and other research methods, this paper deeply studies the feasibility and basic ideas of the construction of intelligent security system in Shahe Higher Education Park, and forms basic experience and typical practices through the project construction, which further promotes the more intelligent, standardized and scientific safety management in colleges and universities. It really provides an important theoretical basis and practical guidance for the opening and sharing between higher education parks and universities.

关键词： Intelligent Security System Higher Education Park Open Sharing

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MicroR-9c-5p and novel-mir50 co-target Akt to regulate Lasioderma serricorne reproduction

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Insect Science 2024年第1期31卷 106-118页

作者： Yi yan dong-dong Qin Hong yang Kang-Kang Xu Can Li Wen-Jia yang Provincial Key Laboratory for Agricultural Pest Management of Mountainous Region Institute of EntomologyGuizhou UniversityGuiyangChina Guizhou Provincial Key Laboratory for Rare Animal and Economic Insect of the Mountainous Region College of Biology and Environmental EngineeringGuiyang UniversityGuiyangChina

High fecundity is a common characteristic of insect pests which increases the difficulty of population control.Serine/threonine kinase Akt is an indispensable component of the insulin signaling pathway.Silencing of LsAkt severely hinders reproduction in Lasioderma serricorne,a stored product insect pest.However,the post-transcriptional pathway of LsAkt in L.serricorne remains unknown.This study identified 2 binding sites of miR-9c-5p and novel-mir50 in the coding sequences of LsAkt.The expression profiles of 2 microRNAs(miRNAs)and LsAkt displayed an opposite pattern during the adult stages.Luciferase reporter assay showed that novel-mir50 and miR-9c-5p could downregulate the expression of LsAkt.Overexpression of miR-9c-5p and novel-mir50 by injection of mimics inhibited the expression of LsAkt and reduced oviposition,decreased egg hatchability,and blocked ovarian development.It also decreased the expression of genes involved in ovarian development(LsVg and LsVgR)and the nutritional signaling pathway(LsTOR,LsS6K,and Ls4EBP),and reduced the phosphorylation of Akt.Conversely,injection of miR-9c-5p and novel-mir50 inhibitors induced the expressions of LsAkt,LsVg,LsVgR,LsTOR,LsS6K,and Ls4EBP,enhanced Akt phosphorylation level,and accelerated ovarian development.Injection of bovine insulin downregulated the expression of miR-9c-5p and novel-mir50 and upregulated the LsAkt expression.It also rescued the reproductive development defects associated with miR-9c-5p/novel-mir50 overexpression,forming a positive regulatory loop of insulin signaling.These results indicate that miR-9c-5p/novel-mir50 regulates the female reproduction of L.serricorne by targeting Akt in response to insulin signaling.The data also demonstrate the effects of the insulin/miRNA/Akt regulatory axis in insect reproduction.

关键词： Akt insulin Lasioderma serricorne microRNA reproduction

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Miniaturized, Wide Stopband Filter Based on Shielded Capacitively Loaded SIW Resonators

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Chinese Journal of Electronics 2024年第2期33卷 456-462页

作者： yan ZHENG Hanyu TIAN Yuandan dong University of Electronic Science and Technology of China (UESTC)

Based on the full-mode capacitively loaded substrate integrated waveguide（SIW） resonator and the miniaturized shielded half-mode capacitively loaded SIW（S-HMCSIW） cavities, a novel compact high-performance filter is proposed. The footprint of the half-mode SIW（HMSIW） is further reduced due to the application of the capacitive-loading technique. By applying cross coupling, the proposed SIW filter's transmission zero enhances the stopband rejection and shows excellent selectivity. For the bandpass filter, the measured |S21| and |S11| are better than 1.09 d B and-14 d B, respectively. And a 3-d B fractional bandwidth（FBW） of 9.14–10.76 GHz（FBW=16.2%）is also observed. The filter achieves a wide stopband with a-20 d B out-of-band rejection up to 2.69f0（f0= 10 GHz）,with a size of 0.39λg× 0.51λgonly. Good agreement between measurement and simulation is obtained.

关键词： Bandpass filter Capacitively loaded Compact filter Shielded cavity Substrate integrated waveguide (SIW)

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Nanocrystalline WSe_(2)excels at high-performance anode for Na storage via a facile one-pot hydrothermal method

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Tungsten 2024年第1期6卷 248-258页

作者： Hai-yan Zou Lei Fang Gang Yu dong Wang State Key Laboratory of Chem/Bio-Sensing and Chemometrics Provincial Hunan Key Laboratory for Graphene Materials and DevicesCollege of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082China Changxing County Quality and Technology Supervision and Testing Center Huzhou 313100China

For the next large-scale energy storage systems,sodium-ion batteries(SIBs)with excellent electrochemical performance are promising.However,the exploration of anode materials with high specific capacity,fascinating cycling stability and rate capability is still restricted.Among transition metal dichalcogenides(TMDs),tungsten diselenide(WSe_(2))has been regarded as an effective anode material for SIBs and has been extensively studied,due to high theoretical capacity and unique twodimensional layered structure.Herein,nanocrystalline WSe_(2)is prepared by a facile one-pot hydrothermal method.Compared with the micro-scale WSe_(2),benefiting from the high specific surface area of highly ordered nano-flake structures and short ion/electron transport paths,nanocrystalline WSe_(2)shows excellent electrochemical performance in Na storage.After 1000 cycles at a current density of 2 A·g^(-1),a high specific capacity of 264.4 mA·h·g^(-1)is still maintained.The full cell matched with the Na_(3)V_(2)(PO_(4))_(3) cathode can deliver an excellent reversible specific capacity of 196.5 mA·h·g^(-1)after 100 cycles at 0.5 A·g^(-1).

关键词： Tungsten diselenide Transition metal dichalcogenides Hydrothermal Sodium-ion batteries Layered structure

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Fine-grained grid computing model for Wi-Fi indoor localization in complex environments

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Journal of Electronic Science and Technology 2024年第1期22卷 42-52页

作者： yan Liang Song Chen Xin dong Tu Liu School of Computer Engineering Chengdu Technological UniversityChengdu611730China HAN Networks Corporation Limited Beijing100094China

The fingerprinting-based approach using the wireless local area network(WLAN)is widely used for indoor localization.However,the construction of the fingerprint database is quite time-consuming.Especially when the position of the access point(AP)or wall changes,updating the fingerprint database in real-time is difficult.An appropriate indoor localization approach,which has a low implementation cost,excellent real-time performance,and high localization accuracy and fully considers complex indoor environment factors,is preferred in location-based services(LBSs)applications.In this paper,we proposed a fine-grained grid computing(FGGC)model to achieve decimeter-level localization accuracy.Reference points(RPs)are generated in the grid by the FGGC model.Then,the received signal strength(RSS)values at each RP are calculated with the attenuation factors,such as the frequency band,three-dimensional propagation distance,and walls in complex environments.As a result,the fingerprint database can be established automatically without manual measurement,and the efficiency and cost that the FGGC model takes for the fingerprint database are superior to previous methods.The proposed indoor localization approach,which estimates the position step by step from the approximate grid location to the fine-grained location,can achieve higher real-time performance and localization accuracy simultaneously.The mean error of the proposed model is 0.36 m,far lower than that of previous approaches.Thus,the proposed model is feasible to improve the efficiency and accuracy of Wi-Fi indoor localization.It also shows high-accuracy performance with a fast running speed even under a large-size grid.The results indicate that the proposed method can also be suitable for precise marketing,indoor navigation,and emergency rescue.

关键词： Fine-grained grid computing (FGGC) Indoor localization Path loss Random forest Reference points(RPs)

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Multiple Nanoparticles Coupling Strategy for Enhancing Optical Filter Performance of Spectral Splitter Used in Photovoltaic/Thermal System

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Journal of Thermal Science 2024年第1期33卷 368-382页

作者： LIANG Huaxu HUANG Xin WANG Fuqiang CHENG Ziming dong yan School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of New Energy Harbin Institute of Technology at WeihaiWeihai 264209China School of Materials Science and Engineering Nanyang Technological UniversitySingapore 639798Singapore

Selective absorptive nanofluid can pre-absorb certain sunlight wavelength that cannot be used by PV and transmits remaining sunlight to the surface of PV,which can decouple PV from the thermal receiver spatially.In order to improve the harvesting of electricity and high-temperature thermal nanofluid,it is important to design an optimal optical filter window(transmit sunlight with wavelengths of 732-1067 nm to the surface of the photovoltaic cell and absorb the remaining sunlight).However,designing optimal optical filter is facing following challenges:(1) inherently narrow selective absorptivity property of single nanoparticle;(2) simplified numerical calculation method calculating transmittance;(3) ignoring the shape of the nanoparticle.In this study,the idea of using multiple nanoparticles coupling effect to design an optical filter is proposed,which can superimpose the narrow absorption bandwidth of different nanoparticles to obtain a wide absorption bandwidth of the whole system.In addition,an improved transmission method considering light-matter interaction at air/vessel and liquid/vessel interfaces is adopted to compute the transmittance.The results calculated by improved transmission method are more accurate than widely used traditional Lambert-Beer law,which is verified by experimental test.Furthermore,the effect of nanoparticle shape on spectral transmittance is also investigated,which shows that spiny Ag can approximately extend absorbance from 400 nm to 600 nm compared to nanosphere silver.Finally,the results show that optical filter efficiency of nanofluids with multiple nanoparticles coupling(Ag,spiny Ag,ZnO,ITO) can reached up to 35%.

关键词： solar energy PV/T nanofluid optimal optical filter radiative transfer spectral splitting

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Transient elastography with controlled attenuation parameter for the diagnosis of colorectal polyps in patients with nonalcoholic fatty liver disease

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World Journal of Clinical Cases 2024年第12期12卷 2050-2055页

作者： Lan Wang yan-Fei Li Li-Feng dong Department of Gastroenterology Beijing Chuiyangliu HospitalBeijing 100022China

BACKGROUND The severity of nonalcoholic fatty liver disease(NAFLD)and lipid metabolism are related to the occurrence of colorectal polyps.Liver-controlled attenuation parameters(liver-CAPs)have been established to predict the prognosis of hepatic steatosis patients.AIM To explore the risk factors associated with colorectal polyps in patients with NAFLD by analyzing liver-CAPs and establishing a diagnostic model.METHODS Patients who were diagnosed with colorectal polyps in the Department of Gastroenterology of our hospital between June 2021 and April 2022 composed the case group,and those with no important abnormalities composed the control group.The area under the receiver operating characteristic curve was used to predict the diagnostic efficiency.Differences were considered statistically significant when P0.05).When the liver-CAP was greater than 291 dB/m,colorectal polyps were more likely to occur.CONCLUSION The levels of TG and liver-CAP in patients with colorectal polyps are significantly greater than those patients without polyps.Liver-CAP alone can be used to diagnose NAFLD with colorectal polyps.

关键词： Colorectal polyps Nonalcoholic fatty liver disease Liver-controlled attenuation parameter Liver fibroscan Diagnostic model

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