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Global well-posedness for the 2D critical dissipative quasi-geostrophic equation

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Science china Mathematics 2007年第4期50卷 485-494页

作者： zhi-fei zhang school of mathematical sciences, peking university, Beijing 100871, china school of mathematical sciences Peking University Beijing 100871 China

We study the initial value problem for the 2D critical dissipative quasi-geostrophic equation. We prove the global existence for small data in the scale invariant Besov spaces ? p,1 2/p , 1 ? p ? ∞. In particular, for p = ∞, our result does not impose any regularity on the initial data. Our proofs are based on an exponential decay estimate of the semigroup $e^{{ - t\kappa ( - \Delta )}^{\alpha}} $ and the use of space-time Besov spaces.

关键词： quasi-geostrophic equation Besov space Littlewood-Paley decomposition well-posedness 3.Q3.

Self-assembly of perovskite nanocrystals:From driving forces to applications

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Journal of Energy Chemistry 2024年第1期88卷 561-578,I0013页

作者： Yi Li fei zhang school of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering(Tianjin) Tianjin 300072China

Self-assembly of metal halide perovskite nanocrystals(NCs)into superlattices can exhibit unique collective properties,which have significant application values in the display,detector,and solar cell *** review discusses the driving forces behind the self-assembly process of perovskite NCs,and the commonly used self-assembly methods and different self-assembly structures are ***,we summarize the collective optoelectronic properties and application areas of perovskite superlattice ***,we conclude with an outlook on the potential issues and future challenges in developing perovskite NCs.

关键词： Self-assembly Metal halide perovskite Nanocrystals Driving forces

The role of lipid metabolism in osteoporosis:Clinical implication and cellular mechanism

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Genes & Diseases 2024年第4期11卷 220-233页

作者： Jing zhang Wenhui Hu zhi Zou Yuheng Li fei Kang Jianmei Li Shiwu Dong College of Bioengineering Chongqing UniversityChongqing 400044China Department of Biomedical Materials Science College of Biomedical EngineeringArmy Medical University(Third Military Medical University)Chongqing 400038China State Key Laboratory of Trauma and Chemical Poisoning Army Medical University(Third Military Medical University)Chongqing 400038China

In recent years,researchers have become focused on the relationship between lipids and bone metabolism ***,many diseases related to lipid metabolism dis-orders,such as nonalcoholic fatty liver disease,atherosclerosis,obesity,and menopause,are associated with osteoporotic *** has been clinically observed in humans that these lipid metabolism disorders promote changes in osteoporosis-related indicators bone mineral density and bone ***,similar osteoporotic phenotype changes were observed in high-fat and high-cholesterol-induced animal *** lipid metabolism(such as increased oxidized lipids and elevated plasma cholesterol)affects bone microenvironment ho-meostasis via cross-organ communication,promoting differentiation of mesenchymal stem cells to adipocytes,and inhibiting commitment towards ***,disturbances in lipid metabolism affect the bone metabolism balance by promoting the secretion of cyto-kines such as receptor activator of nuclear factor-kappa B ligand by osteoblasts and stimulating the differentiation of ***,this review addresses the possible link be-tween lipid metabolism disorders and osteoporosis and elucidates the potential modulatory mechanisms and signaling pathways by which lipid metabolism affects bone metabolism *** also summarize the possible approaches and prospects of intervening lipid meta-bolismforosteoporosistreatment.

关键词： Bone homeostasis Cross-organ communication Lipid metabolism Osteoclast Osteoporosis

Correlative factors of poor prognosis and abnormal cellular immune function in patients with Alzheimer’s disease

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World Journal of Clinical Cases 2024年第6期12卷 1063-1075页

作者： Hua Bai Hong-Mei Zeng Qi-Fang zhang Yue-zhi Hu fei-fei Deng Department of Neurology The Third Affiliated Hospital of Guizhou Medical University in ChinaDuyun 558099Guizhou ProvinceChina Department of Neurology Guizhou Medical UniversityDuyun 558099Guizhou ProvinceChina Key Laboratory of Medical Molecular Biology Guizhou Medical UniversityGuiyang 550004Guizhou ProvinceChina

BACKGROUND Alzheimer’s disease(AD)is a serious disease causing human dementia and social *** quality of life and prognosis of AD patients have attracted much *** role of chronic immune inflammation in the pathogenesis of AD is becoming more and more *** To study the relationship among cognitive dysfunction,abnormal cellular immune function,neuroimaging results and poor prognostic factors in *** A retrospective analysis of 62 hospitalized patients clinical diagnosed with AD who were admitted to our hospital from November 2015 to November *** cognitive dysfunction performance characteristics,laboratory test data and neuroimaging data from medical records within 24 h of admission,including Mini Mental State Examination Scale score,drawing clock test,blood T lymphocyte subsets,and neutrophils and lymphocyte ratio(NLR),disturbance of consciousness,extrapyramidal symptoms,electroencephalogram(EEG)and head nucleus magnetic spectroscopy(MRS)and other *** logistic regression analysis was used to determine independent prog-nostic *** modified Rankin scale(mRS)was used to determine whether the prognosis was *** correlation between drug treatment and prognostic mRS score was tested by the rank sum *** Univariate analysis showed that abnormal cellular immune function,extrapyramidal symptoms,obvious disturbance of consciousness,abnormal EEG,increased NLR,abnormal MRS,and complicated pneumonia were related to the poor prognosis of AD *** logistic regression analysis showed that the decrease in the proportion of T lym-phocytes in the blood after abnormal cellular immune function(odd ratio:2.078,95%confidence interval:1.156-3.986,P<0.05)was an independent risk factor for predicting the poor prognosis of *** number of days of donepezil treatment to improve cognitive function was negatively correlated with mRS score(r=0.578,P<0.05).CONCLUSION The decrease in the proportion of T

关键词： Alzheimer’s disease Cellular immunity Prognosis T lymphocytes Magnetic resonance spectroscopy

3. robust anisotropic diffusion filtering algorithm for sparse view neutron computed tomography 3. image reconstruction

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Nuclear Science and Techniques 2024年第3期35卷 13-29页

作者： Yang Liu Teng-fei Zhu zhi Luo Xiao-Ping Ouyang school of Nuclear Science and Engineering North China Electric Power UniversityBeijing 102206China State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Xi’an 710024China

The most critical part of a neutron computed tomography(NCT) system is the image processing algorithm,which directly affects the quality and speed of the reconstructed *** types of noise in the system can degrade the quality of the reconstructed ***,to improve the quality of the reconstructed images of NCT systems,efficient image processing algorithms must be *** anisotropic diffusion filtering(ADF) algorithm can not only effectively suppress the noise in the projection data,but also preserve the image edge structure information by reducing the diffusion at the image ***,we propose the application of the ADF algorithm for NCT image *** compare the performance of different algorithms in NCT systems,we reconstructed images using the ordered subset simultaneous algebraic reconstruction technique(OS-SART) algorithm with different regular terms as image processing *** the iterative reconstruction,we selected two image processing algorithms,the Total Variation and split Bregman solved total variation algorithms,for comparison with the performance of the ADF ***,the filtered back-projection algorithm was used for comparison with an iterative *** reconstructing the projection data of the numerical and clock models,we compared and analyzed the effects of each algorithm applied in the NCT *** on the reconstruction results,OS-SART-ADF outperformed the other algorithms in terms of denoising,preserving the edge structure,and suppressing *** example,when the 3. Shepp–Logan was reconstructed at 25 views,the root mean square error of OS-SART-ADF was the smallest among the four iterative algorithms,at only *** universal quality index,mean structural similarity,and correlation coefficient of the reconstructed image were the largest among all algorithms,with values of 0.9877,0.9878,and 0.9887,respectively.

关键词： NCT OS-SART Sparse-view Anisotropic diffusion filtering

Maslov-type index and brake orbits in nonlinear Hamiltonian systems

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Science china Mathematics 2007年第6期50卷 761-772页

作者： Duan-zhi zhang school of {3. {3., peking university, Beijing 100871, china 1. school of mathematical sciences Peking University Beijing 100871 China

In this paper, we study the Maslov-type index theory for linear Hamiltonian systems with brake orbits boundary value conditions and its applications to the existence of multiple brake orbits of nonlinear Hamiltonian s... 详细信息

关键词： brake orbit Maslov-type index relative Morse index dual variational method 58E05 70H05 3.C25

P-symmetric Subharmonic Solutions for Nonlinear Hamiltonian Systems

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Acta Mathematica Sinica,English Series 2024年第6期40卷 1388-1408页

作者： Duan zhi zhang zhi Hao ZHAO school of mathematical sciences Nankai UniversityTianjin 300071P.R.China

In this paper,we prove that for each positive k≡1 mod m there exists a P-symmetric kmτ-periodic solution xk for asymptotically linear mτ-periodic Hamiltonian systems,which are nonautonomous and endowed with a *** the P-symmetric Hamiltonian function is semi-positive,one can prove,under a new iteration inequality of the Maslov-type P-index,that xk_(1) and xk_(2) are geometrically distinct for k_(1)/k_(2)≥(2n+1)m+1;and xk_(1),xk_(2) are geometrically distinct for k_(1)/k_(2)≥m+1 provided xk_(1) is non-degenerate.

关键词： P-symmetric subharmonic Hamiltonian systems Maslov-type index theory iteration inequality asymptotically linear

Elliptical encirclement control capable of reinforcing performances for UAVs around a dynamic target

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Defence Technology（防务技术） 2024年第2期32卷 104-119页

作者： fei zhang Xingling Shao Yi Xia Wendong zhang National Key Laboratory for Electronic Measurement Technology School of Instrument and ElectronicsNorth University of ChinaTaiyuan030051China

Most researches associated with target encircling control are focused on moving along a circular orbit under an ideal environment free from external ***,elliptical encirclement with a time-varying observation radius,may permit a more flexible and high-efficacy enclosing solution,whilst the non-orthogonal property between axial and tangential speed components,non-ignorable environmental perturbations,and strict assignment requirements empower elliptical encircling control to be more challenging,and the relevant investigations are still *** this line,an appointed-time elliptical encircling control rule capable of reinforcing circumnavigation performances is developed to enable Unmanned Aerial Vehicles(UAVs)to move along a specified elliptical path within a predetermined reaching *** remarkable merits of the designed strategy are that the relative distance controlling error can be guaranteed to evolve within specified regions with a designer-specified convergence ***,wind perturbations can be online counteracted based on an unknown system dynamics estimator(USDE)with only one regulating parameter and high computational *** tool demonstrates that all involved error variables are ultimately limited,and simulations are implemented to confirm the usability of the suggested control algorithm.

关键词： Elliptical encirclement Reinforced performances Wind perturbations UAVs

Synergistic effect between Er-doped MoS_(2)nanosheets and interfacial Mo-N coupling phases for enhanced electrocatalytic hydrogen evolution

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Rare Metals 2024年第3期43卷 1301-1308页

作者： Nian-Peng Li Lei zhang Hua zhang Fan-fei Min Lei Wang Sam Toan Xi-Jun Liu Guang-{3. Hu State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines School of Materials Science and EngineeringAnhui University of Science and TechnologyHuainan232001China Donghai Laboratory Zhoushan316021China Department of Chemical Engineering University of Minnesota-DuluthDuluthMN55812USA school of Ecology and Environmental Science Institute for Ecological Research and Pollution Control of Plateau LakesYunnan UniversityKunming650504China MOE Key Laboratory of New Processing Technology for Non-Ferrous Metals and Materials Guangxi Key Laboratory of Processing for Non-Ferrous Metals and Featured MaterialsGuangxi UniversityNanning530004China

Hydrogen production via electrochemical water splitting is a promising and green *** one of the most representative transition metal sulfides layered materials,Molybdenum disulfide(MoS_(2))has immense potential for the hydrogen evolution reaction(HER).We successfully prepared a nitrogen-doped carbon(NC)in situ-grown erbium-doped MoS_(2)polyhedral structure(Er-MoS_(2)/NC)that incorporates an interfacial Mo-N coupling phase.

关键词： hydrogen interfacial coupling