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Splitting of Operators and Operator Equations

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Acta Mathematica Sinica,English Series 2023年第6期39卷 1085-1100页

作者： Chun Yuan Deng Wan Yu ZHANG School of Mathematics Science South China Normal UniversityGuangzhou 510631P.R.China

In this paper,we consider the splitting operators into the product of two positive operators.For given operators A and T∈B(H)with A≥0 and R(A)=R(T),if T can be splitted as T=AX for some positive operator X,then the existence of X and the properties of T are studied.The related research are the solutions of operator equations T=XAX and TX=XAX,which have some particular properties and broad applications in many fields.The conditions for the existence of solutions or idempotent solutions of these kinds of equations are studied and new representations of the general solutions are given.

关键词： Projection positive operator operator equation Moore-Penrose inverse

Combinatorial screening via high-throughput preparation:Thermoelectric performance optimization for n-type Bi-Te-Se film with high average zT>1

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Journal of Materials Science & Technology 2023年第29期160卷 18-27页

作者： Guangyu Han Wei Zhu Siming Guo Jie Zhou Yutong Liu Yuan Deng School of Materials Science and Engineering Beihang UniversityBeijing 100083China Research Institute for Frontier Science Beihang UniversityBeijing 100083China Key Laboratory of Intelligent Sensing Materials and Chip Integration Technology of Zhejiang Province(2021E10022) Hangzhou Innovation Institute of Beihang UniversityHangzhou 310052China

Thermoelectric materials have drawn extensive interest due to the direct conversion between electricity and heat,however,it is usually a time-consuming process for applying traditional“sequential”meth-ods to grow materials and investigate their properties,especially for thermoelectric films that typically require fine microstructure control.High-throughput experimental approaches can effectively accelerate materials development,but the methods for high-throughput screening of the microstructures require further study.In this work,a combinatorial high-throughput optimization solution of material properties is proposed for the parallel screening and optimizing of composition and microstructure,which involves two distinctive types of high-throughput fabrication approaches for thin films,along with a new portable multiple discrete masks based high-throughput preparation platform.Thus,Bi_(2)Te_(3-x)Se_(x)thin film library with 196 throughputs for locating the optimized composition is obtained in one growth cycle.In addition,another thin film library composed of 31 materials with traceable process parameters is built to further investigate the relationship between microstructure,process,and thermoelectric performance.Through high-throughput screening,the Bi_(2)Te_(2.9)Se_(0.1)film with(00l)orientation is prepared with a peak zT value of 1.303 at 353 K along with a high average zT value of 1.047 in the interval from 313 to 523 K.This method can be also extended to the discovery of other functional thin films with a rapid combinatorial screening of the composition and structure to accelerate material optimization.

关键词： High-throughput preparation Thermoelectric performance Bi-Te-Se film Combinatorial screening

Development and Tests of ZW-126/D2000-40 Vacuum Circuit Breakers with Controlled Switching Technology

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CSEE Journal of Power and Energy Systems 2022年第1期8卷 249-257页

作者： Yu Tian Jiayuan Xu Yuan Deng Yongxing Wang Enyuan Dong Jiyan Zou Dalian University of Technology Dalian 116024China State Grid Pinggao Group Pingdingshan 467001China

A ZW-126/D2000-40 type single-break vacuum circuit breaker(VCB)with controlled switching technology is designed and produced in this paper.The results of type tests based on IEC and GB standards are presented.A 126 kV singlebreak vacuum interrupter(VI)with 3/4 coil axial magnetic field(AMF)contacts is used in the VCB,which can interrupt short currents of 40 kA.The external insulation of the VI is provided by SF_(6) at 0.1 MPa.In order to match the 126 kV single-break VI and controlled switching device,a long-stroke electro-magnetic force actuator(EMFA)with 16 kN closing holding force and 3.5 m/s average opening speed is designed.Moreover,a position tracking controlled switching device based on closed-loop control using the technology of a fuzzy control algorithm and pulse width modulation is applied to the controlled switching device.This device is applied to control the coil current of EMFA and the electromagnetic force,so as to control the EMFA to follow the ideal position curve.The type tests of 126 kV VCB are all passed according to the IEC62271-100 and GB1984-2014,including dielectric tests,basic short-circuit tests,shortline fault tests,out-of-phase tests,etc.The strong capacitive current breaking capacity and mechanical strength of the VCB are proved by the capacitive current switching test of class C2,electrical endurance test of class E2 and mechanical endurance test of class M2.The electromagnetic compatibility(EMC)tests are passed according to the IEC61000-4.The controlled switching test of capacitive current was successful according to IEC62271-302 and GB/T30846-2014,and the controlled switching accuracy is less than±0.5 ms.The test results show that the VCB has excellent performance,which has broad application prospects in special occasions at a 126 kV voltage level,such as a switching capacitor and no-load transformer,etc.

关键词： Controlled switching electro-magnetic force actuator(EMFA) single-break type test vacuum circuit breaker(VCB)

Continuous synthesis of ultra-fine fiber for wearable mechanoluminescent textile

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Nano Research 2023年第7期16卷 9379-9386页

作者： Shulong Chang Yuan Deng Na Li Lijun Wang Chong-Xin Shan Lin Dong Key Laboratory of Material Physics Ministry of EducationSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450052China State Key Laboratory of Luminescence and Applications Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China

Continuous mechanoluminescence(ML)fibers and fiber-woven textiles have the potential to serve as new wearable devices for sensors,healthcare,human-computer interfacing,and Internet of Things.Considering the demands on wearability and adaptability for the ML textiles,it is essential to realize the continuous synthesis of fiber,while maintaining a desired small diameter.Here,we develop a novel adhere-coating method to fabricate ML composite fiber,consisting of a thin polyurethane(PU)core and ZnS:Cu/polydimethylsiloxane(PDMS)shell,with the outer diameter of 120μm.By diluting PDMS to tune the thickness of liquid coating layer,droplets formation has been effectively prevented.The composite fiber exhibits a smooth surface structure and superior ML performances,including high brightness,excellent flexibility,and stability.In addition,a weft knitting textile fabricated by the continuous ML fiber can be easily delighted by manually stretching,and the ML fibers can emit visible signals upon human motion stimuli when woven into commercial cloth.Such continuous ultra-fine ML fibers are promising as wearable sensing devices for human motion detection and human-machine interactions.

关键词： mechanoluminescence fiber continuous synthesis wearable textile

Immobilization of antimony in soil and groundwater using ferro-magnesium bimetallic organic frameworks

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Journal of Environmental Sciences 2023年第3期125卷 194-204页

作者： Le yuan JianleWang Zuqi Zhong Jiguang Li Hong deng School of Environment and Energy Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Resource RecyclingSouth China University of TechnologyGuangzhou 510006China Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation Beibu Gulf UniversityQinzhou 535000China Guangdong Engineering and Technology Research Center for Environmental Nanomaterials South China University of TechnologyGuangzhou 510006China

Sb(Ⅲ) is often detected in contaminated soil and groundwater. Hence, high-efficiency technology is needed. In this study, bimetallic organic frameworks were used for the first time to immobilize Sb(Ⅲ) from contaminated soil and groundwater. The materials were synthesized by the hydrothermal method. Both ends of the prepared material were hexagonal tip rods,and the length became shorter as the ratio of Fe/Mg decreased. The bimetallic organic framework with a Fe/Mg feeding ratio of 0.5 was the optimum material for Sb(Ⅲ) removal, which could effectively immobilize Sb(Ⅲ). The adsorption isotherm was fitted well with the Freundlich model, and the optimal adsorption capacity can reach 106.97 mg/g. The adsorption capacity of 84% can be completed in 10 min, which conformed to the pseudo-second-order kinetics. The Fe^(3+)could enhance the stability of the material, and the Mg^(2+)was conducive to freeing up adsorption sites for binding Sb(Ⅲ) and forming stable chemical adsorption. Ion exchange is the predominant mechanism to remove Sb(Ⅲ). After 14 days of remediation of Sb(Ⅲ) contaminated soil, the Toxicity Characteristic Leaching Procedure(TCLP)-leached concentrations of Sb(Ⅲ) were reduced by 86%, 91% and 94% when the material dosages were1%, 2% and 3%, respectively. Immobilization of Sb(Ⅲ) in soil resulted in a conversion of antimony speciation from more easily bioavailable species to less bioavailable species, further contributing to reduce the environmental risk of antimony. The results indicate that ferromagnesium bimetallic organic frameworks may serve as a kind of promising materials for the immobilization of Sb(Ⅲ) in contaminated soil and groundwater.

关键词： Antimony Ferro-magnesium bimetallic organic frameworks(MOFs) Soil Groundwater

Metarelation2vec:A Metapath-Free Scalable Representation Learning Model for Heterogeneous Networks

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Tsinghua Science and Technology 2024年第2期29卷 553-575页

作者： Lei Chen yuan Li Yong Lei Xingye deng School of Information and Electrical Engineering Hunan University of Science and TechnologyXiangtan 411201China School of Computer Science and Engineering Hunan University of Science and TechnologyXiangtan 411201China

Metapaths with specific complex semantics are critical to learning diverse semantic and structural information of heterogeneous networks(HNs)for most of the existing representation learning models.However,any metapaths consisting of multiple,simple metarelations must be driven by domain experts.These sensitive,expensive,and limited metapaths severely reduce the flexibility and scalability of the existing models.A metapath-free,scalable representation learning model,called Metarelation2vec,is proposed for HNs with biased joint learning of all metarelations in a bid to address this problem.Specifically,a metarelation-aware,biased walk strategy is first designed to obtain better training samples by using autogenerating cooperation probabilities for all metarelations rather than using expert-given metapaths.Thereafter,grouped nodes by the type,a common and shallow skip-gram model is used to separately learn structural proximity for each node type.Next,grouped links by the type,a novel and shallow model is used to separately learn the semantic proximity for each link type.Finally,supervised by the cooperation probabilities of all meta-words,the biased training samples are thrown into the shallow models to jointly learn the structural and semantic information in the HNs,ensuring the accuracy and scalability of the models.Extensive experimental results on three tasks and four open datasets demonstrate the advantages of our proposed model.

关键词： metarelation random walk heterogeneous network metapath representation learning

Distributed game strategy for unmanned aerial vehicle formation with external disturbances and obstacles

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Frontiers of Information Technology & Electronic Engineering 2022年第7期23卷 1020-1031页

作者： Yang yuan Yimin deng Sida LUO Haibin DUAN State Key Laboratory of Virtual Reality Technology and Systems School of Autonomous Science and Electrical EngineeringBeihang UniversityBeijing 100083China School of Mechanical Engineering&Automation Beihang UniversityBeijing 100191China Peng Cheng Laboratory Shenzhen 518000China

We investigate a distributed game strategy for unmanned aerial vehicle(UAV)formations with external disturbances and obstacles.The strategy is based on a distributed model predictive control(MPC)framework and Levy flight based pigeon inspired optimization(LFPIO).First,we propose a non-singular fast terminal sliding mode observer(NFTSMO)to estimate the influence of a disturbance,and prove that the observer converges in fixed time using a Lyapunov function.Second,we design an obstacle avoidance strategy based on topology reconstruction,by which the UAV can save energy and safely pass obstacles.Third,we establish a distributed MPC framework where each UAV exchanges messages only with its neighbors.Further,the cost function of each UAV is designed,by which the UAV formation problem is transformed into a game problem.Finally,we develop LFPIO and use it to solve the Nash equilibrium.Numerical simulations are conducted,and the efficiency of LFPIO based distributed MPC is verified through comparative simulations.

关键词： Distributed game strategy Unmanned aerial vehicle(UAV) Distributed model predictive control(MPC) Levy flight based pigeon inspired optimization(LFPIO) Non-singular fast terminal sliding mode observer(NFTSMO) Obstacle avoidance strategy

Synergistic creation of highly stable strain-insensitive pressure sensors by in-plane strain modulation and quasi-homogenous interfacial design

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Journal of Materials Science & Technology 2023年第28期159卷 72-80页

作者： Xuyang Feng Shaoxiong Hu Jiajie Yu Zhanpeng Guo Rui Wang Wei Zhu Yuan Deng School of Materials Science and Engineering Beihang UniversityBeijing 100191China Key Laboratory of Intelligent Sensing Materials and Chip Integration Technology of Zhejiang Province Hangzhou Innovation Institute of Beihang UniversityHangzhou 310052China Research Institute for Frontier Science Beihang UniversityBeijing 100083China

The urgent requirement of electronic skin conformably attached to nonplanar surfaces to provide sta-ble monitoring in areas of healthcare,prosthetics,and robotics promotes the development of strain-insensitive/unperturbed pressure sensors.The main challenges lie in:(1)stretchability and conduc-tive stability of flexible electrodes and(2)mechanical stability of heterogeneous interfaces.This study presents a highly stable strain-insensitive pressure sensor achieved by in-plane strain modulation and quasi-homogenous interfacial design.Strain modulation of stretchable electrodes by both periodic mi-crostructured engineering and pre-stretching strategies(called“island-ripple”)was employed to suppress microcracks propagation.The improvement in stretchability and cyclic conductive stability of electrodes was identified by finite element analysis and experimental verification.The pre-stretched microconed stretchable electrode with a low sheet resistance of 0.546sq^(−1) shows a maximum deformation of up to 80%and excellent cyclic conductive stability over 10000 times under 30%strain.Quasi-homogenous interface strategy by the CNTs/PDMS system was employed to enhance the mechanical and electrical sta-bility of the electrode-active materials interface,demonstrating a strong peel strength and shear strength of>40.9 N/m and>124.8 kPa,respectively.The as-prepared strain-insensitive pressure sensor provides constant sensing performance over 5000 stretching-releasing cycles within 20%stretching.In addition,a 4×4 pixel strain-insensitive pressure sensor array with reduced cross-talk circuit design was further integrated to identify the shape and weight of different objects under strains.The stretchability and sta-bility of our sensor enable it to be applied in stretchable electronics with great potential.

关键词： Strain-insensitive/unperturbed pressure sensor Stretchable electrode Finite element analysis Quasi-homogenous design

Effect of wall-disruption on nutrient composition and in vitro digestion of camellia and lotus bee pollens

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Food Science and Human Wellness 2024年第3期13卷 1567-1577页

作者： yuan yuan Shun Zhong ZeYuan Deng Guangyan Li Jinwu Zhang Hongyan Li State Key Laboratory of Food Science and Resources Nanchang UniversityNanchang 330047China Nanchang Tongxin Zichao Biological Engineering Co. Ltd.Nanchang 330052China

The nutrient digestion,absorption and biological activity of bee pollen may be limited due to the complex pollen wall.Here,the effect of superfine grinding technology on the release of nutrients from bee pollen were investigated,and their antioxidant activities and in vitro digestion were explored in this study.Results showed that the content of nutrients in bee pollen increased after wall disruption.Among them,fat content increased by 22.55%-8.31%,protein content increased by 0.54%-4.91%,starch content increased by 36.31%-48.64%,soluble sugar content increased by 20.57%-29.67%,total phenolic acid content increased by 11.73%-86.98%and total flavonoids content increased by 14.29%-24.79%.At the same time,the antioxidant activity increased by 14.84%-46.00%.Furthermore,the active components such as phenolic compounds in the wall-disruption bee pollen were more readily to be released during the in vitro digestion,and easier to be absorbed because of their higher bioaccessibility.Antioxidant activities during in vitro digestion were also improved in walldisruption bee pollen.These findings provide evidence that bee pollen wall disruption was suggested,thus,it is more conducive to exerting the value of bee pollen in functional foods.

关键词： Bee pollen Nutrients Wall disruption Phenolic compounds In vitro digestion