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Geometric Constraints for Global Regularity of 3D Shear Thickening Fluids

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 205-210页

作者： Jia-qi Yang Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen518063China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing100190China

We consider the relation between the direction of the vorticity and the global regularity of 3D shear thickening *** is showed that a weak solution to the non-Newtonian incompressible fluid in the whole space is stron... 详细信息

关键词： direction of the vorticity non-Newtonian fluid global regularity

Electrochemical synthesis of trimetallic nickel-iron-copper nanoparticles via potential-cycling for high current density anion exchange membrane water-splitting applications

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Journal of Energy Chemistry 2024年第2期89卷 535-542,I0012页

作者： Ziqi Zhang Sheng Wan Hanbo Wang Jinghan he Ruige Zhang Yuhang qi Haiyan Lu State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012JilinChina

Hydrogen is known for its elevated energy density and environmental compatibility and is a promising alternative to fossil *** water electrolysis utilizing renewable energy sources has emerged as a means to obtain high-purity ***,electrocatalysts used in the process are fabricated using conventional wet chemical synthesis methods,such as sol-gel,hydrothermal,or surfactantassisted approaches,which often necessitate intricate pretreatment procedures and are vulnerable to post-treatment ***,this study introduces a streamlined and environmentally conscious one-step potential-cycling approach to generate a highly efficient trimetallic nickel-iron-copper electrocatalyst in situ on nickel *** synthesized material exhibited remarkable performance,requiring a mere 476 mV to drive electrochemical water splitting at 100 mA cm^(-2)current density in alkaline ***,this material was integrated into an anion exchange membrane watersplitting device and achieved an exceptionally high current density of 1 A cm^(-2)at a low cell voltage of2.13 V,outperforming the noble-metal benchmark(2.51 V).Additionally,ex situ characterizations were employed to detect transformations in the active sites during the catalytic process,revealing the structural transformations and providing inspiration for further design of electrocatalysts.

关键词： Electrocatalytic water splitting Hydrogen evolution reaction Oxygen evolution reaction Electrochemical synthesis Anion exchange membrane

The Orthogonal Bases of Exponential Functions Based on Moran-Sierpinski Measures

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1804-1824页

作者： qi Rong DENG Xing Gang he Ming Tian LI Yuan Ling YE School of Mathematics and Statistics Center for Applied Mathematics of Fujian Province&Key Laboratory of Analytical Mathematics and Applications(Ministry of Education)Fujian Normal UniversityFuzhou350117P.R.China School of Mathematics and Statistics Key Lab NAA-MOE and Hubei Key Lab-Math.Sci.Central China Normal UniversityWuhan430079P.R.China School of Mathematical Sciences&South China Research Center for Applied Mathematics and Interdisciplinary Studies South China Normal UniversityGuangzhou510631P.R.China

Let An∈M2(ℤ)be integral matrices such that the infinite convolution of Dirac measures with equal weightsμ{A_(n),n≥1}δA_(1)^(-1)D*δA_(1)^(-1)A_(2)^(-2)D*…is a probability measure with compact support,where D={(0,0)^(t),(1,0)^(t),(0,1)^(t)}is the Sierpinski *** prove that there exists a setΛ⊂ℝ2 such that the family{e2πi〈λ,x〉:λ∈Λ} is an orthonormal basis of L^(2)(μ{A_(n),n≥1})if and only if 1/3(1,-1)A_(n)∈Z^(2)for n≥2 under some metric conditions on A_(n).

关键词： Moran-Sierpinski measures orthonormal basis of exponential functions self-affine measures spectral measures

Understanding the spatial interaction of ultrasounds based on three-dimensional dual-frequency ultrasonic field numerical simulation

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China Foundry 2024年第1期21卷 29-43页

作者： Zhao-yang Yin qi-chi Le Yan-chao Jiang Da-zhi Zhao qi-yu Liao qi Zou Key Lab of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China

A transient 3D model was established to investigate the effect of spatial interaction of ultrasounds on the dual-frequency ultrasonic field in magnesium alloy *** effects of insertion depth and tip shape of the ultrasonic rods,input pressures and their ratio on the acoustic field distribution were discussed in ***,the spacing,angle,and insertion depth of two ultrasonic rods significantly affect the interaction between distinct *** a result,various acoustic pressure distributions and cavitation regions are *** spherical rods mitigate the longitudinal and transversal attenuation of acoustic pressure and expand the cavitation volume by 53.7%and 31.7%,respectively,compared to the plate and conical *** the input pressure will enlarge the cavitation region but has no effect on the acoustic pressure distribution *** acoustic pressure ratio significantly affects the pressure distribution and the cavitation region,and the best cavitation effect is obtained at the ratio of 2:1(P15:P20).

关键词： dual-frequency ultrasonic numerical model acoustic pressure spatial interaction magnesium alloy

Towards Semi-supervised Classification of Abnormal Spectrum Signals Based on Deep Learning

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Chinese Journal of Electronics 2024年第3期33卷 721-731页

作者： Tao JIANG Wanqing CheN Hangping ZHOU Jinyang he Peihan qi School of Cyber Engineering Xidian University State Key Laboratory of Integrate Service Networks Xidian University Guangzhou Institute of Technology Xidian University

In order to cope with the heavy labor cost challenge of the manual abnormal spectrum classification and improve the effectiveness of existing machine learning schemes for spectral datasets with interference-to-signal ratios,we proposes a semi-supervised classification of abnormal spectrum signals(SSC-ASS),aimed at addressing some of the challenges in abnormal spectrum signal(ASS) classification tasks.A significant advantage of SSC-ASS is that it does not require manual labeling of every abnormal data,but instead achieves high-precision classification of ASSs using only a small number of labeled ***,the method can to some extent avoid the introduction of erroneous information resulting from the complex and variable nature of abnormal signals,thereby improving classification ***,SSC-ASS uses a memory AutoEncoder module to efficiently extract features from abnormal spectrum signals by learning from the reconstruction ***,SSC-ASS combines convolutional neural network and the K-means using a DeepCluster framework to fully utilize the unlabeled ***,SSC-ASS also utilizes pre-training,category mean memory module and replaces pseudo-labels to further improve the classification accuracy of *** we verify the classification effectiveness of SSC-ASS on synthetic spectrum datasets and real on-air spectrum dataset.

关键词： Deep learning Costs Memory management Memory modules Manuals Feature extraction Labeling

Ordered Bicontinuous Network Structures Regulated by Orientational Interactions in a Rod-Coil Block Copolymer

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Chinese Journal of Polymer Science 2024年第5期42卷 636-642,I0008页

作者： Xiao-Lin Lyu Shi-Chu Yang An-qi Xiao Ping-Ping Hou Wei Zhang Hong-Bing Pan Zhi-Hao Shen Xing-he Fan qi-Feng Zhou Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China Key Laboratory of Advanced Materials Technologies International(HongKong Macao and Taiwan)Joint Laboratory on Advanced Materials TechnologiesCollege of Materials Science and EngineeringFuzhou UniversityFuzhou350108China

The rich phase behavior of block copolymers(BCPs)has drawn great attention in recent ***,the double diamond(DD)phase is rarely obtained because of the competition between the minimization of interfacial energy and packing ***,a rod-coil BCP containing mesogen-jacketed liquid crystalline polymer is designed to acquire ordered bicontinuous network *** reduction of internal energy originating from the orientational interaction among the rod blocks can compensate for the free energy penalty of packing frustration to stabilize the DD *** resulting BCP can also experience lamellae-to-DD and double gyroid-to-lamellae transitions by changing the annealing *** results make the rod-coil BCP an excellent candidate for the self-assembly of ordered network structures,demonstrating great potential in nanopatterning and metamaterials.

关键词： Block copolymer Rod-coil Ordered bicontinuous phase Double diamond Double gyroid

Cosmological Constraints on Neutrino Masses in Light of JWST Red and Massive Candidate Galaxies

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Research in Astronomy and Astrophysics 2024年第4期24卷 7-12页

作者： Jian-qi Liu Zhi-qi Huang Yan Su School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China CSST Science Center for the Guangdong-Hong Kong-Macao Greater Bay Area Zhuhai 519082China

The overabundance of the red and massive candidate galaxies observed by the James Webb Space Telescope(JWST)implies efficient structure formation or large star formation efficiency at high redshift z~*** the scenario of a low or moderate star formation efficiency,because massive neutrinos tend to suppress the growth of structure of the universe,the JWST observation tightens the upper bound of the neutrino *** A cold dark matter cosmology and a star formation efficiency∈[0.05,0.3](flat prior),we perform joint analyses of Planck+JWST and Planck+BAO+JWST,and obtain improved constraints∑m_(ν)he above assumptions,the inverted mass ordering,which implies ∑m_(ν)≥0.1 eV,is excluded by Planck+BAO+JWST at 92.7% confidence level.

关键词： (cosmology:)cosmological parameters galaxies:abundances galaxies:formation neutrinos

General multi-attack detection for continuous-variable quantum key distribution with local local oscillator

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Chinese Physics B 2024年第5期33卷 255-262页

作者：康茁刘维琪齐锦贺晨 School of Information Science and Technology Northwest UniversityXi'an 710127China

Continuous-variable quantum key distribution with a local local oscillator(LLO CVQKD)has been extensively researched due to its simplicity and *** practical security of an LLO CVQKD system,there are two main attack modes referred to as reference pulse attack and polarization attack ***,there is currently no general defense strategy against such attacks,and the security of the system needs further ***,we employ a deep learning framework called generative adversarial networks(GANs)to detect both *** first analyze the data in different cases,derive a feature vector as input to a GAN model,and then show the training and testing process of the GAN model for attack *** proposed model has two parts,a discriminator and a generator,both of which employ a convolutional neural network(CNN)to improve *** results show that the proposed scheme can detect and classify attacks without reducing the secret key rate and the maximum transmission *** only establishes a detection model by monitoring features of the pulse without adding additional devices.

关键词： CVQKD generative adversarial network attack classification

Prediction of bedload transport inside vegetation canopies with natural morphology

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Journal of Hydrodynamics 2024年第3期36卷 556-569页

作者： Li he Yu-qi Shan Chao Liu Hui Cao Xing-nian Liu Yakun Guo State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu610065China Institute for Disaster Management and Reconstruction Sichuan UniversityChengdu610065China China Yangtze Power Co. Ltd.Yichang443002China Hubei Key Laboratory of Intelligent Yangtze and Hydroelectric Science Yichang443002China Faculty of Engineering and Informatics University of BradfordBradfordUK

Due to vegetation drag and vegetation-generated turbulence,bedload transport in vegetated channels is more complicated than that in nonvegetated *** is challenging to obtain accurate predictions of bedload transport in vegetated *** studies generally used rigid circular cylinders to simulate vegetation,and the impact of plant morphology on bedload transport was typically ignored;these methods deviate from natural scenarios,resulting in prediction errors in transport rates of more than an order of *** study measured bedload transport rates inside ***,*** and *** canopies and in arrays of rigid cylinders for *** impact of plant morphology on bedload transport in vegetated channels was *** the canopies of natural morphology,the primary factor driving bedload transport is the near-bed turbulent kinetic energy(TKE),which consists of both bed-generated and vegetation-generated turbulence.A method was proposed to predict the near-bed TKE inside canopies with natural *** the same solid volume fraction of plants,the transport rate inside canopies with a natural morphology is greater than or equal to that within an array of rigid cylinders,depending on the plant *** finding indicates that plant morphology has a significant impact on transport rates in vegetated regions and cannot be ignored,which is typical in *** classic bedload transport equations(the Meyer-Peter-Müller,Einstein,Engelund and Dou equations),which are suitable for bare channels(no vegetation),were modified in terms of the near-bed *** predicted near-bed TKE was inserted into these four equations to predict the transport rate in canopies with natural morphology.A comparison of the predictions indicated that the Meyer-Peter-Müller equation had the highest accuracy in predicting the transport rate in vegetated landscapes.

关键词： Vegetated landscapes turbulent kinetic energy(TKE) bedload transport plant morphology predictive methods