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The symmetric space,strong isotropy irreducibility and equigeodesic properties

Science China Mathematics 2024年第1期67卷 129-148页

作者： Ming xu Ju Tan School of Mathematical Sciences Capital Normal UniversityBeijing 100048China School of Microelectronics and Data Science Anhui University of TechnologyMa'anshan 243032China

A smooth curve on a homogeneous manifold G/H is called a Riemannian equigeodesic if it is a homogeneous geodesic for any G-invariant Riemannian metric.The homogeneous manifold G/H is called Riemannian equigeodesic,if for any x∈G/H and any nonzero y∈Tx(G/H),there exists a Riemannian equigeodesic c(t) with c(0)=x and ■(0)=y.These two notions can be naturally transferred to the Finsler setting,which provides the definitions for Finsler equigeodesics and Finsler equigeodesic spaces.We prove two classification theorems for Riemannian equigeodesic spaces and Finsler equigeodesic spaces,respectively.Firstly,a homogeneous manifold G/H with a connected simply connected quasi compact G and a connected H is Riemannian equigeodesic if and only if it can be decomposed as a product of Euclidean factors and compact strongly isotropy irreducible factors.Secondly,a homogeneous manifold G/H with a compact semisimple G is Finsler equigeodesic if and only if it can be locally decomposed as a product,in which each factor is Spin(7)/G2,G2/SU (3) or a symmetric space of compact type.These results imply that the symmetric space and the strongly isotropy irreducible space of compact type can be interpreted by equigeodesic properties.As an application,we classify the homogeneous manifold G/H with a compact semisimple G such that all the G-invariant Finsler metrics on G/H are Berwald.It suggests a new project in homogeneous Finsler geometry,i.e.,to systematically study the homogeneous manifold G/H on which all the G-invariant Finsler metrics satisfy a certain geometric property.

关键词： equigeodesic equigeodesic space flag manifold orbit type stratification symmetric space strongly isotropy irreducible space

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Design and Implementation of a High-Sensitivity Magnetic Sensing System Based on GMI Effect

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Journal of Beijing Institute of Technology 2024年第3期33卷 237-247页

作者： Wenzhu Wu Ming xu Changlin Han Junquan Tang Jia xu Lin xu mingxin Qin Department of Electronic Engineering Army Medical UniversityChongqing 400038China Chongqing Medical and Pharmaceutical College Chongqing 401331China Department of Intelligence Science and Technology National University of Defense TechnologyChangshaChangsha 410073China Intelligent Game and Decision Lab Beijing 100091China

A high-sensitivity magnetic sensing system based on giant magneto-impedance(GMI)effect is designed and fabricated.The system comprises a GMI sensor equipped with a gradient probe and an signal acquisition and processing module.A segmented superposition algorithm is used to increase target signal and reduce the random noise.The results show that under unshielded,room temperature conditions,the system achieves successful detection of weak magnetic fields down to 2 pT with a notable sensitivity of 1.84×108V/T(G=1000).By applying 17 overlays,the segmented superposition algorithm increases the power proportion of the target signal at 31 Hz from6.89%to 45.91%,surpassing the power proportion of the 2 Hz low-frequency interference signal.Simultaneously,it reduces the power proportion of the 20 Hz random noise.The segmented superposition process effectively cancels out certain random noise elements,leading to a reduction in their respective power proportions.This high-sensitivity magnetic sensing system features a simple structure,and is easy to operate,making it highly valuable for both practical applications and broader dissemination.

关键词： high-sensitivity magnetic field sensing system GMI effect segmented superposition algorithm

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Amino acids modified nanoscale zero-valent iron:Density functional theory calculations,experimental synthesis and application in the Fenton-like degradation of organic solvents

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Journal of Environmental Sciences 2024年第1期135卷 296-309页

作者： Xingchen Yang Fucheng ming Jianlong Wang Lejin xu Department of Nuclear Engineering and Technology School of Energy and Power EngineeringHuazhong University of Science and TechnologyWuhan 430074China China-EU Institute for Clean and Renewable Energy Huazhong University of Science and TechnologyWuhan 430074China Institute of Nuclear and New Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China Beijing Key Laboratory of Radioactive Wastes Treatment Tsinghua UniversityBeijing 100084China

To improve the adsorption and catalytic performance of heterogeneous Fenton-like catalysts for oil wastes,amino acids were used to modify nanoscale zero-valent iron(AA@Fe^(0)),which were applied in the Fenton-like degradation of organic solvents(tributyl phosphate and n-dodecane,named TBP and DD).Twelve amino acids,i.e.,glycine(Gly),alanine(Ala),leucine(Leu),proline(Pro),phenylalanine(Phe),methionine(Met),cysteine(Cys),asparagine(Asn),serine(Ser),glutamic acid(Glu),lysine(Lys)and arginine(Arg),were selected and calculated by density functional theory(DFT).The optimized structure,charge distribution,the highest occupied molecular orbital(HOMO),the lowest unoccupied molecular orbital(LUMO),interaction region indicator(IRI)isosurface map and adsorption energy of AA@Fe^(0),AA@Fe^(0)-TBP and AA@Fe^(0)-DD were studied,which indicated that Fe is more likely to approach and charge transfer with-COO and-NH_(3) on theα-carbon of amino acids.There is strong attraction between Fe and–COO,and Van der Waals force between Fe and-NH_(3),respectively.In the interaction of AA@Fe^(0)with TBP and DD,Van der Waal force plays an important role.AA@Fe^(0)was synthesized in laboratory and characterized to investigate physicochemical properties.In Fenton-like degradation of organic solvents,the change of COD in water phase during the degradation process as well as the volume of the organic phase after the reaction were investigated.The results of calculations combined with experiments showed that Ser-modified Fe^(0)performed the best in these amino acids,with 98%removal of organic solvents.A possible catalytic mechanism was proposed in which amino acids acted a linking role between Fe and organic solvents,activating H_(2)O_(2)to generate hydroxyl radicals for the degradation of organic solvents.

关键词： Amino acids Nanoscale zero-valent iron Density functional theory Organic solvents Fenton-like degradation

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Twisted Integration of Complex Oxide Magnetoelectric Heterostructures via Water‑Etching and Transfer Process

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Nano-Micro Letters 2024年第1期16卷 360-369页

作者： Guannan Yang Guohua Dong Butong Zhang xu xu Yanan Zhao Zhongqiang Hu ming Liu State Key Laboratory for Manufacturing Systems Engineering Electronic Materials Research LaboratoryKey Laboratory of the Ministry of EducationEngineering Research Center of Spin Quantum Sensor ChipsUniversities of Shaanxi ProvinceSchool of Electronic Science and EngineeringXi’an Jiaotong UniversityXi’an 710049People’s Republic of China

Manipulating strain mode and degree that can be applied to epitaxial complex oxide thin films have been a cornerstone of strain engineering.In recent years,lift-off and transfer technology of the epitaxial oxide thin films have been developed that enabled the integration of heterostructures without the limitation of material types and crystal orientations.Moreover,twisted integration would provide a more interesting strategy in artificial magnetoelectric heterostructures.A specific twist angle between the ferroelectric and ferromagnetic oxide layers corresponds to the distinct strain regulation modes in the magnetoelectric coupling process,which could provide some insight in to the physical phenomena.In this work,the La_(0.67)Sr_(0.33)MnO_(3)(001)/0.7Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.3PbTiO_(3)(011)(LSMO/PMN-PT)heterostructures with 45.and 0.twist angles were assembled via water-etching and transfer process.The transferred LSMO films exhibit a fourfold magnetic anisotropy with easy axis along LSMO.A coexistence of uniaxial and fourfold magnetic anisotropy with LSMO[110]easy axis is observed for the 45°Sample by applying a 7.2 kV cm^(−1)electrical field,significantly different from a uniaxial anisotropy with LSMO[100]easy axis for the 0°Sample.The fitting of the ferromagnetic resonance field reveals that the strain coupling generated by the 45°twist angle causes different lattice distortion of LSMO,thereby enhancing both the fourfold and uniaxial anisotropy.This work confirms the twisting degrees of freedom for magnetoelectric coupling and opens opportunities for fabricating artificial magnetoelectric heterostructures.

关键词： Magnetoelectric heterostructures Twist angle Epitaxial lift-off Magnetic anisotropy Ferromagnetic resonance

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Dual Frequency Transformer for Efficient SDR-to-HDR Translation

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Machine Intelligence Research 2024年第3期21卷 538-548页

作者： Gang xu Qibin Hou ming-ming Cheng Tianjin Media Computing Center College of Computer ScienceNankai UniversityTianjin300000China

The SDR-to-HDR translation technique can convert the abundant standard-dynamic-range (SDR) media resources to high-dynamic-range (HDR) ones, which can represent high-contrast scenes, providing more realistic visual experiences. While recent vision Transformers have achieved promising performance in many low-level vision tasks, there are few works attempting to leverage Transformers for SDR-to-HDR translation. In this paper, we are among the first to investigate the performance of Transformers for SDR-to-HDR translation. We find that directly using the self-attention mechanism may involve artifacts in the results due to the inappropriate way to model long-range dependencies between the low-frequency and high-frequency components. Taking this into account, we advance the self-attention mechanism and present a dual frequency attention (DFA), which leverages the self-attention mechanism to separately encode the low-frequency structural information and high-frequency detail information. Based on the proposed DFA, we further design a multi-scale feature fusion network, named dual frequency Transformer (DFT), for efficient SDR-to-HDR translation. Extensive experiments on the HDRTV1K dataset demonstrate that our DFT can achieve better quantitative and qualitative performance than the recent state-of-the-art methods. The code of our DFT is made publicly available at https://***/CS-Gangxu/DFT.

关键词： Standard-dynamic-range to high-dynamic-range(SDR-to-HDR)translation Transformer dual frequency attention(DFA) frequency-aware feature decomposition efficient model.

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Synthesis,Style Editing,and Animation of 3D Cartoon Face

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Tsinghua Science and Technology 2024年第2期29卷 506-516页

作者： ming Guo Feng xu Shunfei Wang Zhibo Wang ming Lu Xiufen Cui Xiao Ling School of Software and BNRist Tsinghua UniversityBeijing 100084China Department of Multimedia and Smart Guangdong OPPO Mobile Telecommunications Corp.Ltd.Dongguan 523860China Intel Labs IntelBeijing 100089China

As a popular kind of stylized face,cartoon faces have rich application scenarios.It is challenging to create personalized 3D cartoon faces directly from 2D real photos.Besides,in order to adapt to more application scenarios,automatic style editing,and animation of cartoon faces is also a crucial problem that is urgently needed to be solved in the industry,but has not yet had a perfect solution.To solve this problem,we first propose“3D face cartoonizer”,which can generate high-quality 3D cartoon faces with texture when fed into 2D facial images.We contribute the first 3D cartoon face hybrid dataset and a new training strategy which first pretrains our network with low-quality triplets in a reconstruction-then-generation manner,and then finetunes it with high-quality triplets in an adversarial manner to fully leverage the hybrid dataset.Besides,we implement style editing for 3D cartoon faces based on k-means,which can be easily achieved without retrain the neural network.In addition,we propose a new cartoon faces'blendshape generation method,and based on this,realize the expression animation of 3D cartoon faces,enabling more practical applications.Our dataset and code will be released for future research.

关键词： cartoon 3D face animation computer graphics

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Hybrid Network Model Based on Data Enhancement for Short-term Power Prediction of New PV Plants

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 77-88页

作者： Shangpeng Zhong Xiaoming Wang Bin xu Hongbin Wu ming Ding the Anhui Province Key Laboratory of Renewable Energy Utilization and Energy Saving Hefei University of TechnologyHefei 230009China the State Grid Anhui Electric Power Research Institute Hefei 230061China

This study proposes a hybrid network model based on data enhancement to address the problem of low accuracy in photovoltaic(PV)power prediction that arises due to insuffi cient data samples for new PV plants.First,a time-series gener ative adversarial network(TimeGAN)is used to learn the distri bution law of the original PV data samples and the temporal correlations between their features,and these are then used to generate new samples to enhance the training set.Subsequently,a hybrid network model that fuses bi-directional long-short term memory(BiLSTM)network with attention mechanism(AM)in the framework of deep&cross network(DCN)is con structed to effectively extract deep information from the origi nal features while enhancing the impact of important informa tion on the prediction results.Finally,the hyperparameters in the hybrid network model are optimized using the whale optimi zation algorithm(WOA),which prevents the network model from falling into a local optimum and gives the best prediction results.The simulation results show that after data enhance ment by TimeGAN,the hybrid prediction model proposed in this paper can effectively improve the accuracy of short-term PV power prediction and has wide applicability.

关键词： New photovoltaic(PV)plant short-term predic tion time-series generative adversarial network(TimeGAN) hy brid network hyperparameter

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Structure regulating of metal clusters in carbonized metallic organic frameworks for high-efficient microwave absorption via tuning interaction strength between metals and ligands

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Nano Research 2024年第3期17卷 1699-1709页

作者： Chang Sun Kun-Yan Zhao ming-Lu Huang Cheng-Long Luo xu-Dong Chen ming Wang School of Chemistry and Chemical Engineering Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function ManufacturingSouthwest UniversityChongqing 400715China Jieyang Branch of Chemistry and Chemical Engineering Guangdong Laboratory(Rongjiang Laboratory) Jieyang 515200China

Carbonized metallic organic frameworks(CMOF)have been attracting attention in microwave absorption(MA)research area because of their diverse structures,tunable compositions,and rich porosity.Herein,structure regulation on metal clusters in CMOF is achieved by tuning the interaction strength between metals and ligands to enhance microwave absorption performance.Due to relatively weak interaction among copper cations and ligands,copper nanoclusters(CuNC)can be uniformly formed and embedded within the cobalt/zinc(Co/Zn)CMOF.Firstly,copper cations are added to the Co/Zn bimetallic zeolitic imidazolate frameworks(ZIFs).Secondly,the CMOF composite particles with CuNCs(CuNCs/CoZn-CMOF)were developed by a pyrolysis process.The CuNCs/CoZn-CMOF with an appropriate amount of CuNCs can harmonize both dielectric and magnetic losses.As a result,the minimum reflection loss(RLmin)reaches–45.1 dB at a matching thickness of 2.30 mm and the effective absorption bandwidth(EAB)is 8.80 GHz at a thickness of 3.10 mm.The broadband response to electromagnetic waves is attributed to interfacial polarization at CuNCs surface and heterogeneous interfaces,impedance matching and multiple scattering of electromagnetic waves.This study provides a feasible method to develop CMOF microwave absorption materials with high EAB values.

关键词： heterogeneous interface carbonized metallic organic frameworks microwave absorption interfacial polarization

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Effect of drying-wetting cycles on pore characteristics and mechanical properties of enzyme-induced carbonate precipitation-reinforced sea sand

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 291-302页

作者： ming Huang Kai xu Zijian Liu Chaoshui xu mingjuan Cui College of Civil Engineering Fuzhou UniversityFuzhou350108China Xiamen Rail Transit Construction and Development Group Co. Ltd.Xiamen361000China School of Civil Environment and Mining EngineeringThe University of AdelaideAdelaide5005Australia

Enzyme-induced carbonate precipitation(EICP)is an emanating,eco-friendly and potentially sound technique that has presented promise in various geotechnical applications.However,the durability and microscopic characteristics of EICP-treated specimens against the impact of drying-wetting(D-W)cycles is under-explored yet.This study investigates the evolution of mechanical behavior and pore charac-teristics of EICP-treated sea sand subjected to D-W cycles.The uniaxial compressive strength(UCS)tests,synchrotron radiation micro-computed tomography(micro-CT),and three-dimensional(3D)recon-struction of CT images were performed to study the multiscale evolution characteristics of EICP-reinforced sea sand under the effect of D-W cycles.The potential correlations between microstructure characteristics and macro-mechanical property deterioration were investigated using gray relational analysis(GRA).Results showed that the UCS of EICP-treated specimens decreases by 63.7% after 15 D-W cycles.The proportion of mesopores gradually decreases whereas the proportion of macropores in-creases due to the exfoliated calcium carbonate with increasing number of D-W cycles.The micro-structure in EICP-reinforced sea sand was gradually disintegrated,resulting in increasing pore size and development of pore shape from ellipsoidal to columnar and branched.The gray relational degree suggested that the weight loss rate and UCS deterioration were attributed to the development of branched pores with a size of 100-1000 m m under the action of D-W cycles.Overall,the results in this study provide a useful guidancee for the long-term stability and evolution characteristics of EICP-reinforced sea sand under D-W weathering conditions.

关键词： Enzyme-induced carbonate precipitation(EICP) Plant-based urease Drying-wetting(D-W)cycles Microstructure

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Tighter sum uncertainty relations via(α,β,γ)weighted Wigner–Yanase–Dyson skew information

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Communications in Theoretical Physics 2024年第3期76卷 91-99页

作者： Cong xu Zhaoqi Wu Shao-ming Fei School of Mathematical Sciences Capital Normal UniversityBeijing 100048China Department of Mathematics Nanchang UniversityNanchang 330031China Max-Planck-Institute for Mathematics in the Sciences 04103 LeipzigGermany

We establish tighter uncertainty relations for arbitrary finite observables via(α,β,γ)weighted Wigner–Yanase–Dyson((α,β,γ)WWYD)skew information.The results are also applicable to the(α,γ)weighted Wigner–Yanase–Dyson((α,γ)WWYD)skew information and the weighted Wigner–Yanase–Dyson(WWYD)skew information.We also present tighter lower bounds for quantum channels and unitary channels via(α,β,γ)modified weighted Wigner–Yanase–Dyson((α,β,γ)MWWYD)skew information.Detailed examples are provided to illustrate the tightness of our uncertainty relations.

关键词： quantum channels (α,β,γ)WWYD skew information (α,β,γ)MWWYD skew information uncertainty relations

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