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Journal of Rare Earths 2024年第9期42卷 1629-1645,I0001页

作者： lianjie Bi Hua Yan Peilei Zhang Haichuan Shi zhiyuan li Ruidi li School of Materials Science and Engineering Shanghai University of Engineering ScienceShanghai201620China College of Agricultural Science and Engineering Hohai UniversityNanjing211100China Department of Mechanics and Maritime Science Chalmers University of TechnologyGothenburSE41296Sweden State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083China

In this paper,the effects of rare earth oxides on the micro structure and mechanical properties of nickelbased superalloys prepared by high-energy beam processing technology were critically *** focus is on the optimal amount of rare earth oxides that can produce ideal *** attention was paid to their main strengthening mechanisms,including solid solution strengthening mainly in the form of solid solution dissolved in the nickel-based alloy and improving the microstructure of the alloy by grain refinement or fine grain strengthening produced by homogenizing the distribution phase.Y_(2)O_(3),La_(2)O_(3) and CeO_(2) rare earth oxides can also improve the fluidity of the alloy molten pool and reduce the segregation of alloying *** advantages can significantly improve the mechanical properties of the ***,this paper outlines the future research directions of rare earth oxides,aiming to expand their application potential.

关键词： Rare earths High energy beam Nickel-based superalloys Microstructure Mechanical properties

A novel interpretable multilevel wavelet decomposition deep network for actual heartbeat classification

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Science China(Technological Sciences) 2024年第6期67卷 1842-1854页

作者： JIN YanRui li zhiyuan TIAN YuanYuan WEI XiaoYang liU Chengliang School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai200240China

Arrhythmias may lead to sudden cardiac death if not detected and treated in time.A supraventricular premature beat(SPB)and premature ventricular contraction(PVC)are important categories of arrhythmia ***,deep learning methods have been applied to the PVC/SPB heartbeats ***,most researchers have focused on time-domain information of the electrocardiogram and there has been a lack of exploration of the interpretability of the *** this study,we design an interpretable and accurate PVC/SPB recognition algorithm,called the interpretable multilevel wavelet decomposition deep network(IMWDDN).Wavelet decomposition is introduced into the deep network and the squeeze and excitation(SE)-Residual block is designed for extracting time-domain and frequency-domain ***,inspired by the idea of residual learning,we construct a novel loss function for the constant updating of the multilevel wavelet decomposition ***,the IMWDDN is evaluated on the Third China Physiological Signal Challenge Dataset and the MIT-BIH Arrhythmia *** comparison results show IMWDDN has better detection performance with 98.51%accuracy and a 93.75%F1-macro on average,and its areas of concern are similar to those of an expert diagnosis to a certain ***,the IMWDDN has good application value in the clinical screening of PVC/SPB heartbeats.

关键词： actual heartbeat classification electrocardiogram interpretable deep network multilevel discrete wavelet decomposition layer SE-Residual block

A STRONG POSITIVITY PROPERTY AND A RELATED INVERSE SOURCE PROBLEM FOR MULTI-TERM TIME-FRACTIONAL DIFFUSION EQUATIONS

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Acta Mathematica Scientia 2024年第5期44卷 2019-2040页

作者： li HU zhiyuan li Xiaona YANG School of Mathematics and Statistics Ningbo UniversityNingbo315211China School of Mathematical Sciences Xiamen UniversityXiamen361005China

In this article,we consider the diffusion equation with multi-term time-fractional *** first derive,by a subordination principle for the solution,that the solution is positive when the initial value is *** an application,we prove the uniqueness of solution to an inverse problem of determination of the temporally varying source term by integral type information in a ***,several numerical experiments are presented to show the accuracy and efficiency of the algorithm.

关键词： fractional diffusion equation inverse source problem nonlocal observation observation uniqueness Tikhonov regularization

Arginine promotes seed energy metabolism,increasing wheat seed germination at low temperature

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The Crop Journal 2024年第4期12卷 1185-1195页

作者： Jiayu li zhiyuan li Yangyang Tang Jianke Xiao Vinay Nangia Yang liu College of Agronomy Northwest A&F UniversityYangling 712100ShaanxiChina International Center for Agricultural Research in the Dry Areas Rabat 999055Morocco

Low temperatures during germination inhibit seed growth,lead to small and weak seedlings,and significantly reduce the wheat *** the adverse effects of low temperature on wheat seed germination is highly important for achieving high and stable wheat *** this study,Tongmai 6(insensitive)and Zhengmai 113(sensitive),which have different low-temperature sensitivities during germination were treated with low temperature during *** transcriptome,metabolome and physiological data revealed that low temperature decreased the germination rate,downregulated the expression of a large number of genes involved in regulating glycometabolism,and inhibited carbon,nitrogen(especially amino acids)and energy metabolism in the *** content increased at low temperature,and its increase in the low-temperature-tolerant variety was significantly greater than that in the sensitive *** priming experiment showed that treatment with an appropriate concentration of arginine improved the seed germination *** conversion of starch to soluble sugar significantly increased under exogenous arginine conditions,the content of key metabolites in energy metabolism increased,and the utilization of ATP in the seeds *** together,arginine priming increased seed germination at low temperature by relieving inhibition of seed carbon and nitrogen metabolism and improving seed energy metabolism.

关键词： Low temperature Seed germination Arginine Energy metabolism Wheat

MnO-pillared graphene blocks enabling the ultrastable and ultrafast aqueous zinc ion batteries

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Science China Chemistry 2024年第9期67卷 2930-2940页

作者： Zheng liu Zhipeng Qiu zhiyuan li Tong Wei Zhuangjun Fan Huan Pang School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225002China School of Materials Science and Engineering China University of PetroleumQingdao 266580China

Due to the low cost,high theoretical capacity,and environmental friendliness,manganese-based cathodes are regarded as promising alternatives for aqueous zinc ion batteries(AZIBs).However,the practicality of the zinc-manganese system is faced with great challenges,such as the inevitable structural collapse of the cathode and controversial energy storage ***,we propose a novel concept of spatial deposition mechanism through the addition of MnSO_(4) additives in the Mn O-pillared graphene blocks(G-MnO).The covalent interface between MnO nanoparticles and multilayered graphene nanosheets can construct an in-built micro-electric field,which is beneficial for consecutive electron transfer(in both horizontal and vertical directions).On this basis,the surficial activity of MnO confined in the interlayered nano-space is greatly enhanced and provides enough spatial deposition and subsequent reaction site for MnSO_(4) additives,thus firstly extending the surficial controlled process to stereoscopic space,effectively improving the electrochemical performance of ***,the assembled Zn//G-Mn O battery exhibits an excellent rate capability of 281.5 mAhg^(-1)at 0.1 A g^(-1)and 106 mAhg^(-1)at 20 Ag^(-1),and impressive cycling stability(93 mAhg^(-1)remaining after 5,000 cycles).This finding may provide a new opportunity for the rational design of surficial controlled energy storage and conversion devices.

关键词： zinc-ion battery manganese monoxide laminated constructure ultrahigh rate performance graphene

Comparative study on the hydrogen storage performance of as-milled MgRENi rapid quenched alloy catalyzed by metal sulfides

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Journal of Magnesium and Alloys 2024年第5期12卷 2010-2023页

作者： Xiaoping Dong Zhaoqing Zhang liying Yang Shenghai Xin Dandan Su zhiyuan li Department of Mechanical Design and Manufacture and Automation Hebei UniversityBaoding 071000PR China Baoding New Energy Vehicle Power Engineering Technology Research Center Hebei UniversityBaoding 071002PR China Hebei Technology Innovation Center for lightweight of New Energy Vehicle Power System(Preparation) Hebei UniversityBaoding 071002PR China

The composites of Mg_(20)Pr_(1)Sm_(3)Y_(1)Ni_(10)as-quenched alloy and 3 wt.%M(M=CoS,CoS_(2),MoS_(2))catalyst were prepared by high-speed vibration ball *** effects of metal sulfides on the hydrogenation and dehydrogenation dynamics of alloys were *** results show that the as-milled composites contain a large number of amorphous embedded by a small amount of nanocrystals,and there are many point *** ball milling,the crystal grain size in the composites containing CoS is relatively larger,followed by CoS_(2)and MoS_(2)*** hydrogenation,the amorphous phase is crystallized to form Mg_(2)NiH_(4),YH_(3),Pr_(8)H_(18.96),Sm_(3)H_7,Mg,Co or Mo phases,however,Mg_(2)Ni,YH_(2),PrH_(2)and Ni_(3)Y phases appeared after *** maximum hydrogenation capacity of the composites containing CoS,CoS_(2)and MoS_(2)are 3.939,4.265 and 4.507 wt.%,*** hydrogenation saturation ratio of composite containing MoS_(2)is higher than that of the composites containing CoS and CoS_(2).The dehydrogenation activation energy of the composites containing CoS,CoS_(2)and MoS_(2)is 107.76,68.43 and 63.28 ***^(-1).H_(2).On the improvement of hydrogen storage performance of Mg_(20)Pr_(1)Sm_(3)Y_(1)Ni_(10)alloy,the catalytic effect of MoS_(2)sulfide is better than that of CoS_(2)sulfide,and which is better than CoS sulfide.

关键词： Mg_(20)Pr_(1)Sm_(3)Y_(1)Ni_(10)as-quenched alloy CoS CoS_(2)and MoS_(2)sulfide Milling Activation energy Hydrogen storage dynamics

Lead-free(Ba,Sr)TiO_(3)-based ceramics with superior tunable properties by the semi-solution method

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Journal of Advanced Ceramics 2024年第6期13卷 746-756页

作者： Yi Zhao Wenfeng liu Dongsheng Ran Yihang Jin zhiyuan li Chengzhi Zhong Fanyi Kong Shengtao li State Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiaotong UniversityXi’an 710049China Jiaxing Electric Power Company State Grid Zhejiang Electric Power Co. Ltd.Jiaxing 314000China

High-performance dielectric tunable materials with both high dielectric tunability and low dielectric loss are urgently needed for new-generation electronic tunable *** the present study,a new system,(Ba_(0.675)Sr_(0.325))_(1−x)La_(x)Ti_(1−x)MnxO_(3)(x=0.25%,0.5%,0.75%,and 1.0%),was *** acceptor dopant Mn was added to lower dielectric loss,while the donor dopant La was introduced to enhance dielectric *** samples were prepared using the conventional solid-state(CS)reaction method and the semi-solution(SS)*** experimental results showed that the morphology of the ceramics was optimized by further improving the processing *** microstructures,homogeneous grains,and uniform dopant distributions could be achieved successfully by the semi-solution ***,a significant enhancement in the tunable properties was realized owing to the improved microstructure mentioned *** optimum tunable properties occurred in the samples prepared by the semi-solution method at x=0.75%,with a high dielectric tunability of 85.0%,a low dielectric loss of 0.0011,and an excellent figure of merit(FOM)of *** tunable properties of(Ba,Sr)TiO_(3)(BST)ceramics were even superior to those of lead-based materials,with an FOM of approximately *** the results suggested that the semi-solution method rendered BST ceramics more promising for applications in tunable devices.

关键词： microstructure tunable properties (Ba,Sr)TiO_(3)(BST)ceramics semi-solution(SS)method

Foreign Ownership and International Trade Performance in China

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China & World Economy 2024年第2期32卷 42-72页

作者： zhiyuan li Yichun lin Mingyao Xu School of Economics Fudan University Shanghai Institute of International Finance and Economics China School of Economics Fudan UniversityChina

We investigate the causal relationship between foreign ownership and international trade performance by comparing foreign-acquired firms with similar domestic-acquired firms in China with regard to changes in their post-acquisition international trade *** findings indicate that foreign ownership significantly enhanced the probability of both exporting and importing,and strongly increased trade *** ownership took effect from the year of the acquisition and persisted for at least 2 *** stimulated both processing trade and ordinary trade,and expanded products and trading ***-acquisition trade performance also exhibited heterogeneity based on the different pre-acquisition and post-acquisition *** for the underlying mechanisms,we show that firms experienced significant output expansion,increased export dependence,and eased financial constraints after foreign acquisition.

关键词： domestic acquisition foreign acquisition foreign ownership international trade performance

A review of in-situ high-temperature characterizations for understanding the processes in metallurgical engineering

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International Journal of Minerals,Metallurgy and Materials 2024年第11期31卷 2327-2344页

作者： Yifan Zhao zhiyuan li Shijie li Weili Song Shuqiang Jiao Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijing 100081China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

For the rational manipulation of the production quality of high-temperature metallurgical engineering,there are many challenges in understanding the processes involved because of the black box chemical/electrochemical *** overcome this issue,various in-situ characterization methods have been recently developed to analyze the interactions between the composition,microstructure,and solid-liquid interface of high-temperature electrochemical electrodes and molten *** this review,recent progress of in-situ hightemperature characterization techniques is discussed to summarize the advances in understanding the processes in metallurgical ***-situ high-temperature technologies and analytical methods mainly include synchrotron X-ray diffraction(s-XRD),laser scanning confocal microscopy,and X-ray computed microtomography(X-rayμ-CT),which are important platforms for analyzing the structure and morphology of the electrodes to reveal the complexity and variability of their *** addition,laser-induced breakdown spectroscopy,high-temperature Raman spectroscopy,and ultraviolet-visible absorption spectroscopy provide microscale characterizations of the composition and structure of molten *** importantly,the combination of X-rayμ-CT and s-XRD techniques enables the investigation of the chemical reaction mechanisms at the two-phase ***,these in-situ methods are essential for analyzing the chemical/electrochemical kinetics of high-temperature reaction processes and establishing the theoretical principles for the efficient and stable operation of chemical/electrochemical metallurgical processes.

关键词： in-situ characterization methods high-temperature electrochemistry electrodes molten salts interfacial reaction

A novel lightweight computerized ECG interpretation approach based on clinical 12-lead data

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Science China(Technological Sciences) 2024年第2期67卷 449-463页

作者： liU YunQing QIN ChengJin liU JinLei JIN YanRui li zhiyuan ZHAO liQun liU Chengliang School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Key Labof Artificial Intelligence(Ministryof Education) AI InstituteShanghai Jiao Tong UniversityShanghai 200240China Department of Cardiology Shanghai First Peoples Hospital Affiliated to Shanghai Jiao Tong UniversityShanghai 200080China

Although 12-lead electrocardiograms(ECGs)provide a wide range of spatiotemporal characteristics,interpreting them for arrhythmia detection is difficult due to a lack of reliable large-scale clinical ***,we proposed an innovative lightweight computerized ECG interpretation approach based on 12-lead *** model was trained,validated,and tested on 53845 standard 12-lead ECG records collected at Shanghai First People’s Hospital in affiliation with Shanghai Jiao Tong *** experiments revealed that our approach had a classification accuracy of 94.41%in the classification task of seven types of rhythms,which was markedly superior to related single-lead and 12-lead ECG classification ***,the average receiver operating characteristic area under the curve reached a value of 0.940,and the precision values for sinus tachycardia and sinus bradycardia were 0.945 and 0.91,respectively,with specificity values of 0.996 and *** employing our boosting method,we were able to improve the accuracy to 94.85%.To investigate the performance degradation of the proposed neural network in some classes,an ECG cardiologist was enlisted to review questionable ECGs;this process provides a promising direction for network performance ***,the proposed computerized ECG interpretation approach has practical significance because it could help professional physicians analyze patients’heart conditions based on real-time 12-lead ECG or grade their disease severity in advance.

关键词： computerized ECG interpretation large-scale 12-lead clinical ECG database lightweight neural network